Tuesday, December 08, 2009

Fate of the Blue Ball....

The Blue ball has minimal development value for where I want to go with Urocket.
I was going to donate it to the Xprize to hang in their lobby. I talked to my accountant today and learned that I can't have an increase in basis for a self created asset, that's CPA for I won't get any kind of deduction if I donate it. Its basically intact, it would be 100% ready to fly with less than 8 hours of work so next time I'm out at FAR I will bring it home and fix it. Then I will fly it.

Without doing any paperwork I can fly it to 1199 ft AGL and back. To go higher than that I'll need an FAA waiver. So in the next few days I'll do a detailed model of what it can do and write a waiver request. I'll probably fly it in 60 to 90 days to max altitude (more than 10K less than 30Kft) and back to the pad. If anyone wants to fly an experiment on it when I fly it let me know.

  • less than 5Kg,
  • self powered ,
  • 100% open public results

I'll probably let people on the blog vote for their favorite if I get more than one request.

Wednesday, December 02, 2009

Tiger, Jaycee Dugard ,Me ,darwin, and motivation.

(Stick with this it will really end up almost on topic)
The current fascination people have with the Tiger Woods is interesting because the image he projects is perfect, he is a gifted athlete, smart, well spoken, respected, rich, married to a super model, his life is perfect in every way. Yet we learn that at some level he is not satisfied with what he has.

Jaycee Dugard is captured as a little girl raped and held captive for 18 years, yet we read that she had adjusted to her life and even felt some attachment to the monster that did this to her.

Un-happiness in the perfect life and happiness in the horrible life, whats going on?

I think its human nature to adjust your expectations to your situation. Last year my business had the best year ever, I had the time and budget to pursue the LLC dream and work on a really interesting project, I was truly fortunate to have that. It was a great year. In the Month after the contest I've not yet come to grips with the fact that the economy is in the pits and I really can't afford to work on the rockets for awhile. I've got to go work really hard to maintain the business in this climate rather than seeing it grow. (We're down 36% year to date yet we have not laid anyone off) My personal setpoint had adjusted to the thrill and success and its really depressing to try and adjust it back. The vast majority of humanity would be ecstatic to trade places with me, yet I'm depressed about it. 5 years ago I'd be ecstatic, I think we really only react to the changes, not the absolute level of things in our life.

When I stop and ponder this I come it an interesting question. What is the natural state of humans? From an evolutionary standpoint I can see that sit in the corner depressed is not effective and would be selected out of the gene pool. However I can also see that a slight unease or paranoia could have benefits. If one group of humans is satisfied and happy and settles in for the winter, they would be at a disadvantage to another group the was just a little bit uneasy and focused that energy at being more productive and gathering a few more nuts and animal skins for the winter. So what is the natural state of the most productive humans?

What drives productive motivation? Is motivation bordering on obsession good or bad for production? Should I just rest and relax for awhile, or shoudl I try and get fired up to work on the things I can actually do, like clean the workshop, develop a simulator, do a peper design for a nanosat vehicle? What purpose does recharge and satisfaction setpoint "reset" have in the process? My wife has studyied a lot of Buddhist philosophy, IE live in the now and be happy with what you have. Any really productive Buddhist scientists and engineers? Is society better served by the hedonist pursuing things in the free market where he is driven to create value so he can have pleasure? I've always though Maslow's hierarchy of needs was a better gage that pure hedonism. The happiest times in my life have been associated with creating something , or bringing an idea to realization. I've posed a lot of hard questions all much less clear than the rocket equation, yet more important when trying to accomplish things in the world.

Monday, November 23, 2009

Cleaning the workshop.....

My Son and I spent the better part of Saturday trying to clean up the workshop.
On Sunday I took 180lbs of scrap metal to the recyclers.

It was hard to scrap things I'd put hundreds of hours of work into, but that is what is needed.

The stuff I did for LLC is larger than the scale I intend to work on going forward so very little of it is presently useful.

Trying to return to a normal life, but I still find the end of the LLC leaves a big hole.

I'm putting some focus and effort into work to try an make up for the last few months of neglect and to rebuild the rocket fund.

I'll be the guest on the Space Show this Friday the 27th.

Wednesday, November 11, 2009

Its a bird, its a plane its a drag!

The LLC vehicles have had almost no aerodynamic constraints. The Rocket Racers of Armadillo and Xcor used off the shelf airframes with established functional aerodynamics. Not even spacex has yet dealt with aerodynamics in any complciated way. The Spacex falcon 1 did have aerodyanmic Max Q issues, and probably aerothermal issues, but there were no aerodynamic controls and aerodyamics does not get much simpler than a long round tube with a pointy end.
(The recovery parachutes of the F1 first stage either were not included or failed)

Spacex is about to fly the dragon capsule with hypersonic aerodynamics, aero thermal, and stable parachute deployment and recovery issues. Armadillo is starting to fly to higher altitudes, Masten hopes to soon follow and or surpass what Armadillo has been doing.
Xcor is planing their next rocket vehicle where the aerodynamics include transonic and some aero thermal issues.

From a rocketry stand point the smaller New Space organizations (Masten ,Armadillo and Xcor) are nearing the level of rocketry sophistication reached by the Germans at the end of WWII. Please note that the Germans never flew a supersonic aircraft. (Yes the V2 was supersonic) Get in your time machine fly back to 1946 and ask Chuck Yeager if supersonic is a big deal?

If an LLC L2 vehicle was flown on an airless earth with zero drag and maintained a steady state 4G acceleration (3 g net) it would run out of propellant near 30Km and coast to 119Km before falling back to earth. Using my really simple aerodynamic model... assuming a Masten Glow of 900 lbs, and 25" diameter with very good aerodyamics removing the 25Kg payload and flying the same 4G flight Mastens L2 vehicle would reach about 116Kf or 35Km. Now in practice you would probably have to throttle back to reduce max Q if you picked 300Knots as max Q equivalent then you would have your velocity limited by maxQ until at least 40Kft and one would trade more gravity loss for reduced aerodynamic losses and get to about the same place just over 115K ft.

This not an up and soft land simulation, this is a up up and away simulation with a crash landing at the end. So given the stated goals of both armadillo and Masten to fly payloads to space they will need vehicles that are both higher performing and more aerodynamic than what they presently have.
(A max Q of 300 knots equivalent may not seem like very fast in a world with 500knot airliners, but a skydiver released into a 300 knot airstream would experience more than 8 g of deceleration.)

I vaguely remember Henry Spencer making a comment that the Apollo command module heat shield had an eqiuivalent ISP of 7000. If your going to build reusable vehicles that fly to space and come back its never going to make sense to kill your velocity via propulsion as long as we are using chemical fuels. So when reusable suborbital vehicles start flying to 100km they will need to use aerodynamics to scrub off the energy from the gravitational potential.

Will this look like the space ship 2 shuttle cock? will it look like NASA's hypersonic ring slot parachutes developed for viking and used on every mars landing since? Will it be airplane like?
I think this is going to be a harder problem than many think. Mr Musk of spacex has been quoted as saying that a fly back first stage booster would be a really useful thing to reduce space access costs, but it would cost > $1B to develop. Some solutions look simple like the rocket becomes winged vehicle as shown in Charles Pooley's Microlauncher presentation. I don't think that an easily fabricated simple wing will function well with supersonic shocks, flutter stiffness etc... One wants a shape that can give you decelerating lift at high altitude, does not provide much drag on the way up and is structurally stable at all points in between. This is a you pick any two sort of problem. The U2 had very long thin wings to get get lift at high altitude. Yet it it was a subsonic aircraft and as a result operated in a very narrow box where a few knots faster and it hit Mach buffet and a few knots slower and it stalled.

One can work around these issues by using a combination, like a hypersonic parachute to decelerate you to subsonic followed by rotate open wings to glide back to base.

Whatever features will be used they will require testing. With the exception of xcor all of these vehicles are unmanned. The regulatory environment for testing rockets under the amateur or experimental permit rules are now well defined and reasonable friendly. If one is developing a glide back system one would like to test the basic aero controls, flight, landing etc in an incremental manner. Just try getting the FAA to give you permission to fly such an unmanned vehicle in their airspace? The Aircraft side of the FAA is significantly less understanding than the AST. (Just ask John Carmack) So from a regulatory standpoint one is going to have to fly it as a rocket under AST's jurisdiction. This is not testing that can easily be done under tether, or even at the locations that Armadillo and Masten are currently flying from.

None of this is impossible, its just another layer of problems to be tackled. Anyone have any good recommendations for a good book on supersonic aerodynamics ?

Monday, November 09, 2009

Crystal ball gazing....

Its clear that Armadillo and Masten are going to take their lander technology and pursue scientific and other payloads to the ignoreasphere. (IE the space between 100Kft and 150Km). If we had won any LLC $ at all our plans would be similar. This by itself is not going to change the world. (Masten article in AV week)

In an optimistic scenario it allows both Masten and Armadillo to become cash flow positive and continue to develop. From a pure business stand point one can count the number of heads in the masten shop make some educated guesses about rent and insurance etc.. and one would come up with a burn rate some where between 500K and 1.5M a year. So the new found prize money buys them another year of operation. Today's masten press release had a figure of about 100K per flight. Assuming they have good gross margins and get 20 or so customers a year they have an on-going growing business.

Beyond the scientific payloads to the ignorasphere you will have people like scaled/virgin providing man tended flights to this region for prices double what Masten is quoting for a "Brick" When that starts happening Mastens prices are going to have to plummet to compete.

The next big step is some sort of orbital capability. I don't see a clear revenue path for incremental improvements from high suborbital to orbital. The Technology shown by armadillo and Masten (hover for ~200 sec iat 9.8m/sec) give a DV of 1962m/sec. To reach orbit with a small high drag vehicle (small == high drag) one needs at least 8000 m/sec dv. Giving some credit for vac ISP gains and calling the present vehicles the 2nd of three stages one could probably put a 5 lb "brick" in orbit with a gross lift off on the order of 10000 lb. Is there a market?

Clearly spacex has demonstrated there is a potential market for 200Kg payloads, but 50 to 100 times smaller? Can either Masten or Armadillo grow into this spot without significant outside capital? Only time will tell.

I'm a real fan of simple dumb booster. The series LEO on the cheap has a lot going for it. As I've said before I really liked the Beal Aerospace approach, big simple pressure fed. I just think he aimed too high for the first vehicle. Something 10 times smaller would have been a good start.
Even starting there its hard to rough out a plan that does not take $50M+ to get to cash flow positive and profitable. Virgin recently got investments on that order and maybe they can grow into this space.

I've often thought about writing a detailed business plan to seek funding, but I have major personal resistance to becoming another one on the long list of people that say "just write me a really large check and trust me I'll build a spacecraft that owns the market." To properly assemble a plan that could realistically get funding is a lot of work with low probablity of success.

The engineering is not really even a big part of the problem, one has to also build a functioning organization with Management, recruiting, HR, legal, government liaison, etc.... It would be hard to just bring forth such an organization in a timely manner given infinite funds. Space lauunch is such a broad problem covering so many disciplines It would be really hard to find someone to
organize the business part if you had the perfect engineering team already in place. How many people have a sset up a brand new manufacturing facility on that scale in the U.S. in the last 20 years? Not many.

Where do I go from here? The question is a lot broader than the technical topics discussion I wrote last week. Do I want Unreasonable to be a slightly profitable side business?? Do I want to compete against Masten/Armadillo as a the lowest cost provider? Can I contribute something technically to this 'space'? Do I have the chutzpa to try creating a externally funded start up?
I've worked at funded start ups and my current business that was started with zero outside $ in 1998 was a lot simpler to start and has done well. How far outside of my personal comfort zone would I like to stretch?

I've even contemplated sending a resume to Spacex, but I have not figured out where we could live within driving distance to Hawthorne without a reduction in our standard of living.

On a personal level its been a hard week watching the LLC awards ceremony and having tons of people tell me our accomplishments were amazing. Feels a lot like I think 4th place at the Olympics would feel. Amazing results, just not as amazing as gold,silver and bronze. Its really frustrating at some level.

Over the last year my schedule was up at 5am work on Unreasonable til 8:30 take a shower go to work, come home at 6pm work on unreasonable. This last week I've been getting to work before 7 and leaving around 4:30. Coming home and feeling lost. I still have not gotten up the motivation to tackle the entropy in the workshop.

I'm gathering up some data on the technical performance of Masten, Armadillo, unreasonable and several other interesting ideas and some time in the two weeks I'm going to do an ideas with supporting "numbers" post.

Wednesday, November 04, 2009

On Discovery Channel....

We were on the daily planet show on the discovery channel in Canada last night.
You can see the show.

Tuesday, November 03, 2009

16 hrs of sleep (in a single night!) is helpful....

I slept 16 hours last night and I am feeling much better.
Thanks to everyone for the kind words.

Over the next month or two I'll take some time and describe some of the projects on the
"want to do next" list. I'm going to have to pick one or two off the list. The list is large enough that it will have to undergo significant triage. A smattering of ideas:

Do I work on guidance and controls? (I have a magazine that wants me to publish a seires on the helicopter guidance and controls) I'd like to build a full up system to go on existing airframes that duplicates most of the capabilties of the dragon fly

Do I work to build a hardware in the loop simulator tailored to become an open toolkit for others? I have some really good ideas in this realm ,but I really need to find someone that can help with the core math and transforms part of this. I can do all the basic physics simulation in 2D, but when I try to model things like what a 25 lb gimbaled engine deflection does to to the vehicle in 3D IE accouting for the 3D rotational intetias of both the motor and the rest of the vehicle when the momentum transfers between the two peices are constrained to 2 axis by the gimbal joint, add to this that the deflection changes the rotational inertia of the system in the roll axis my head explodes. As the gimbaled mass is more than 15% of the vehicle weight I don't think you can just ignore the effect. My rocket parts bin does not have any spherical frictionless cows so I can't make thoose assumptions. (If that makes no sense to you you probaly had a different college physics class than I did)

Do I finish my electric pumped hi pressure rocket demonstrator.

Do I do work on better catalysts. I got a really good download of information on Beal's catalyst development and would like to pursue this but the basic equipment to do or hire the flame spray metal application is outside the present budget.

Do I go back to permangenate and static mixing tubes to skip the whole catalyst. (I have all the parts on hand for this experiment so the necessary budget is close to zero)

Do I go back to Lox and ignitors? (The helium cost is a killer)

I really like the small pump work done at LLNL I'd like to duplicate that.

The low cost turbo pump ideas described on Charles Micro Launchers site are of interest.

I have a hankering to build a 10K lb tube wall motor that would be usefull as the first stage in a
reusable booster.

Glide back airframes and or parachutes are of interest.

Do I work on full up vehicles?
This is the most expensive option if I do this I think I will use Wellmate WM35WB for peroxide and WM-6LP for fuel as the WM-6 I used for a fuel tank on silver worked really well.
Using a derivative of silvers propulsion system this could go to 50K ft and then soft land, or well over 100Kt and parachute back.

Any customer(s) with $ to spend could push any one of these items to the top of the list....

Monday, November 02, 2009

After Action Report.

We destroyed silver and badly damaged blue. The root cause was not enough time and budget to do the necessary testing. Primary lesson only work on one vehicle at a time.

In Early September we flew multiple long flights, as long as 106 seconds. We then parked the vehicle. On Thursday I merged the navigation code I'd flown on the helicopter with the hover code on blue. I picked the wrong code branch and it did not have the wiggle correction in it, so it wasted too much thrust wiggling and did not have sufficent thrust to lift off. After sitting with what must have been an in inadequate purge the cat pack was badly corroded. On Saturday I changed the cat pack and added the gain scheduling to correct the wiggles. I was worried based on Friday that it might not get off the ground so I loaded what I calculated to be the minimum necessary propellant+ 2% , it flew for 85 Seconds then crashed on the 2nd pad. See: You Tube from on board and Video looking out. It looks like my code slicing and dicing also missed the roll or yaw control fix I put in the blue ball as yaw seemed largely uncontrolled. Based on the takeoff acceleration we could have put a lot more propellant into the vehicle and done the full 90 seconds.

I was really happy with the way silver turned out. It was very clean , light and capable. I just could not get io hover stably. It looked like a control loop integral wind up issue. From a sportsman ship stand point both Ben and Ian of Masten asked suggested that was the problem. I had turned off the Integral Gain on position hold as one of my first steps, alas the strange mix of code from three sources had a cut and paste error so there was still an integral term inplay even after I thought I'd turned it off. I'm 90 % sure that with 2 extra hours to slow down and review I'd have fixed it. We came very close: Silver ball hover.

The eventual fault that killed it was a bit subtle. On the blue ball when I hit the command abort it shuts the motor off cleanly it just closes the main valve. On the silver we purge on shutdown, and we purge hard, this causes a shut down thrust transient as residual propellants are forced through the motor. Couple that with the choice to center the motor and kill active attitude control when aborting and one gets wild gyrations on abort. Yes can see Ben's video of its final flight.

On a personal level I'm really glad I got the one 94% successful flight out of the blue ball. It at least shows we were close. It also shows what a small team can accomplish. On the flip side we walk away from the contest with nothing tangible to show for the effort. This project has been a really big part of my life for the last year and it leaves a big hole. At the end it became an unhealthy all consuming obsession as the clock wound down and we ran out of time and budget. From a financial stand point it also means no playing with rockets for at least 6 months to a year as I try to rebuild the rocket fund.

Only time will tell if I eventually see the overall project as a positive thing. It does not seem that way this morning.

Thursday, October 29, 2009

Last Post before contest...

I'm waiting for the last batch of Cat screens to heat up in the toaster oven before dipping in the secret sauce. So I have a few minutes. The rest of the day is going to be crazy so I won't post again until after the contest.

Nominally this is a two person team, Myself and My son, but in reality there is a large array of people that help out.

First and foremost is my wife Mariellen, without her support and assistance in a million ways both big and small this would not be possible.

My son. Without his help and countless hours this would not be possible. It has been a real joy to spend three years working with my son on a big project.

Bob our Welder. In the past week he has put in as many hours as we have. Without his assistance we could not possibly have been ready.

Charles Pooley of Microlaunchers. Charles has spent countless days and nights out at FAR helping us test.

Carl Tedesco of Flometrics. Carl has been a help both here iin San Diego and out at the FAR site.
He has offered help with both technical, fabrication and just being there to lend a hand.

Steve Harrington of Flometrics if you need to solve a fulids, flow, valving, heat transfer, or aerodynamics problem Steve is the goto guy. His assitance with figuring out the flow and flluid " science part of the rockets has been invaluable. So if you need anyhting done in this area give Steve a call.

Kevin Baxter. President of the FAR organization. Keven has been the driving force in creating a world class rocket test facility from scratch at FAR.

Mark and Ted of FAR. The other two principals in FAR have been invaluable in their help and assistance.

Michael Carden of XL Space systems. He has been my propellant supplier and peroxide guru for all things related.

Tom and all the guys at NetBurner that have been understanding of the CTO vanishing for every increasing amounts of time.

John Carmack and all the guys at Armadillo for being open, kind and helpful to a competitor.

All the guys at Masten, they have all been supportive and helpful.

Wynn Aung and all the people at the FAA that have been helpful and professional throughout the whole process.

Will ,Nicole Bill, and all the Xprize people that have organized the event for 4 years.

All the neighbors who think I'm crazy, but are still supportive anyway.

All the readers of this blog that have offer encouragement and kind words.

Wednesday, October 28, 2009

Good news...

I went to bed certain that our 180 second vehicle was dead. We split the tank over 20 inches of the main seam. My son and our welder Bob would not give up they got up at 6 am and spent the day grinding bending and otherwise beating the tank back into shape. They then re-welded the bad seam. At 2:30pm this afternoon it passed Hydro. Its clear that we are real close with little margin, but we do not pressurize in the presence of humans so even if it failed we would not hurt anyone. This was a 12 hr detour that we did not need. Its still a Hail Mary to be ready for the 180, but we are not yet dead.

As a result we are probably not going to be ready Friday Morning, its more likely we will try a Friday Afternoon flight and one or more Saturday Flights. I'm a bit hesitant to post the FAR map as we have had some theft problems, but I am going to post it for the next 24 hours.

If you want to come watch the earliest possible start is a Friday Noon safety briefing.
The Saturday Safety briefing will be at 7 am Saturday Morning. If you want to Camp at FAR you can. If yotu are not Xprize or Judges you will need to sign a FAR liabiliy waiver. You must be at the briefing to attend the event. It is very possible that Friday will be canceled entirely.

Far is a good 45 minutes from Mojave, and the road is rough. You may find the map here.

The ball is dropped in the end zone.

The tank failure we had last night is not recoverable in three days. We are not going to fly the 180 second L2 silver ball this year. If Masten continues their recent rapid progress and finishes the L2 180 second flights we will probably never fly the silver ball again. Its basically scrap metal.

At a personal level I've worked on this project for 3 years and spent enough $ to buy a nice house anywhere but CA. . We came oh so very close to fielding two vehicles, a tiny bit less corrosion in a weld and we would have two vehicles ready to fly.(Proof the Silver flew) As a team of two we built and flew two complete vehicles, but the odds are now that we will walk away with nothing to show for our efforts. Its a really really bitter pill.

I'm now going to get a long stream of comments saying you were two guys in a garage up against teams with multimillion dollar budgets. This is true, but there is no junior varsity contest, just the one contest. I started this to compete and hopefully win, its not to be.

My current task is to scrape myself off the floor and try to get the Blue Ball ready to fly. We have a legitimate shot of tying Masten for the L1 2nd prize.

Tuesday, October 27, 2009

Progress ,...

We ground off all the mounting tabs we were not using.
We welded the Safety Vent to the vehicle instead of using a heavy Stainless sanitary clamp.
We shortened the legs etc.... So we need to re-hydro the main tank. We got a pin hole leak where we ground off unused tabs. Argh!!! Weld a plate over and try again.. We needed to get to 425 PSI. The Tank Failed at 350 on the main seam. . We had hydro-ed it to 400 in the spring, so over the last 6 months it lost 50 PSI. Probably means we are done for the 180.

We patched the tank on the blue ball after a hydro failure, we will look at patching this tank in the AM, but 95% sure it means no 180 for us.

Monday, October 26, 2009


I have a theory as to why the cat pack suddenly died. (80% confidence) and I know how to avoid the issue. It was not my cost saving short cut. The old cat pack is being nitric acid stripped and re-plated. I've got all the material for a new no shortcuts CAT pack arriving at 8am Tuesday, with the Waterjet and Plateing house lined up to get a new one made. This should be ready Wednesday Afternoon.

We spent the day removing 40 lbs form the silver ball (Stainless fuel tanks and plumbing and misc unused fittings and bits. We then added back back 20lbs including a New higher capacity composite fuel tank and pressure bottles for external pressurization. The whole vehicle should be back together late Tuesday or Early Wednesday. It could hold double the propellant and it weighs 20 lbs less. The takeoff limitation will now be engine thrust, not propellant capacity.

If I can duplicate my in flight measured ratio of theoretical to actual performance I'll have 200 seconds of hover.

The LLC judges inspected our lunar pad and it passed.

Someone asked me today when I last had 8 hrs of sleep I asked if they meant in a single week?

Going to sleep UPS promises to arrive before 8 am.

Sunday, October 25, 2009

6 Days

Our 90 Second Vehicle is Ready.
Our RTK GPS tests with the helicopter say we have a chance to tie Masten in the 90 sec contest, but beating them outright would require some significant luck.

Our 180 Second vehicle is going to go down to the last minute. I disassembled the Motor and it looks good inside, the screens just look like they all got too hot. I think I need to change my warmup purge sequence. The sad part is that I really don't need to do a Cat pack warmup for normal ops, only for Tether ops as I need finer control of the in initial altitude on tether.

The vehicle flies at least as well as the blue ball, but we need to add a pressurization tank and
make weight reduction modifications to have any margin at all on the 180 second flight. Motor pressure drops are high so we need to hydro to a higher pressure and if the tank fails there we are done. I have parts of a spare Catalyst, but I took a cost reduction short cut on the last batch and they did not last as long as the previous batch. So I need to next day air some screen material and beg the waterjet and plating house to perform a miracle. It is all going to come down to the wire.

As one of the recent Masten posts commented about recent progress "we have had multiple consecutive miracles. " We will need similar to do 180. If we can fly for 180 seconds we can beat Armadillos accuracy, so it becomes a risk reward game.... IE On Saturday morning if we have a vehicle that would cost 50K to reproduce that has a 10% chance of success and a 90 % chance of destruction do we make the attempt? (0.9 * -$50K) vs (0.1 *$1M ) The calculus changes a little bit depending on Masten's result.

Are recently discussed on Twitter, Bon Nova is not going to fly this year.
I know exactly where they are in the process and its a really hard place to be in .
so close, but no realistic chance of completion, we were there last year.

Tuesday, October 20, 2009

Plans Update

We are going to go out to the site On Wedensday Morning set up and work on non-rocket flight things. RTK GPS base, Helicopter testing etc....(Can't fly the rocket on Wedensday, I forgot to Fax my FAA notification)
We will be flight testing Thursday and Friday and I think I have help for those days.
Its really hard to plan more than a day or two in advance but its really likely that I'll need some help during the week next week. So if you were so inclined check in on the blog or unrocket on twitter.

The current flight plans are to attempt the 90 second flight Friday Morning the 30th and the 180 second flight Saturday the 31st. If you want to come out and watch you will need to attend the safety briefing TBD some time late next week in Mojave. You will also need to sign the FAR liability waiver, I'll bring copies to the safety briefing.

The FAR site is about 45 minutes from Mojave out route 14. I'll provide a detailed map at the safety briefing.

The trip includes 10 miles of somewhat rough dirt road. (My wife drives her Honda civic out the road so its not too terrible.) Its actually really fun in my STI.

If you want to attend both days and can be 100% self sufficent you can probably camp on site Thursday Night and Friday. We will be camping on site and we will need our sleep so I'd really appreciate no 3am arrivals.

You can find my E-mail address phonetically in the comments of the previous blog thread.

Sunday, October 18, 2009

A quick update...

Currently in the passenger seat of the car on the way home.
Just spent 4 days at FAR camping. Worked on three things...

1)Navigating Pad to Pad flying the exact desired LLC profile with the helicopter, and new GPS system. This work went very well, many exactly repeatable flights, only one scare the GPS needs more voltage for proper operation than all the other electronics, so one flight the system battery was low and even tired, sun burnt and sleep deprived at dusk I mangaged to save the helicopter by taking over.

2)We had a very poorly timed large project for a customer. It was the largest rocket ever fired at FAR and the test went really well. Can't really say more.

3)We tyried to hover the silver ball. We got the altitude stuff under controll, but never managed a stable hover. Nothing we did in the way of loop tuning seemd to help. Got up before sunrise this morning to carefully look at everything in the system. I did some sweeps of the gimbal actuators trying to precisely measure dead band and hystersis. Came up with a sequience where the actuator moved OPPOSITE of the commanded direction. This jives with observations and as we would hover then just all of a sudden flip over to the abort limit. Seems to come and go depending on how I press on the PCB, I had no replacement with me so it means going home.

My son is in the middle of starting a new business and has other commitments for most of this week. I've got business commitments Monday and Tuesday, but I hope to go out to the site
Tuesday night for more testing. We will be short handed so if you are in the So cal area and don't mind hard work in the sun at a site with no good shelter and no running water we could really use some help.

Monday, October 12, 2009

Definition of Insanity....

Definition of insanity: Doing the same thing over and over and expecting different results.

Clearly we don't think we are doping the same thing, but the results are really similar....

Drive 4 hours, camp, setup test, fly abort, break the vehicle, driver home 4 hours, fix vehicle, lather rinse repeat.

We should have the vehicle back together tonight. We have fabricated a new version of the the part in the gimbal mount we broke, but we still need to fabricate a brace so it won't break again.

We failed to record data on the last flight, so almost no useful information from the test.
(The error was a tired operator error, not a fundamental problem)
I've spent the morning changing software so data will be recorded automagically without any operator intervention, in 3 places, on the ground station PC, on the telemetry box, on an SD card in the vehicle, just to be redundant.

Looking at what data I do have, several things are clear.... proportionally it looks like the gimbal system needs a lot more differential correction than the vanes did.

The system seems to be a lot more sensitive to every thing being level to start with, the vane system just plain ignores tilts of up to 15 degrees, does not even cause a noticeable start up transient. This gimbal vehicle seems to want to start out with a large transient.

On a spherical vehicle its actually really hard to be sure that everything is lined up level.
The IMU is level, the motor is dead level vertically, but I'm sure I have a center of mass offset for the partially full fuel tank. Again the vanes vehicle just ignored the center of mass offset when flying with the permanganate tank.

I'm not a big believer in software only simulations, I like to build real world analogs and test those, this may change my mind. For a long time my todo list has had a hardware in the loop simulator on the list, ie simulate IMU and GPS inputs to the computer, measure the actual valve and motor positions and use these to run the simulation. This will probably be my winter project.

Thursday, October 08, 2009

Off by a factor of 57.295779513.....

I've been playing with the high accuracy RTK GPS on the helicopter.
The software reports stunningly consistent positions etc....
But visually the helicopter wanders all over the world.

I've jsut solved it.
The Old GPS reports position in degrees, new GPS reports position in Radians!
Arghhhhh! Since I never actually looked at the lat lon positions I just told the vehicle to remember where "here" is and report distances from that reference point I never noticed.

I like using the binary records from the GPS's as parsing NEMA style text is a conversion that is not needed. If the binary record reports IEEE double format just use them. Alas The two GPS have different byte orders as well one is big endian one little endian, one reports velocity as heading and speed, one reports as vnorth and veast. I got all of these conversions working, but missed the radians/degrees difference. I'm tired and in a hurry, not the best situation for quality software. If NASA can make these kind of errors I guess I'm in good company. (Remember Mars Climate Orbiter?)

Wednesday, October 07, 2009


I've been working on the Vertical issue, so I have not really gotten to work on the position hold and overall horizontal stability. In viewing the Masten Video Several things are clear,

1)Their motor movement is a lot smaller than mine, I think I probably have the gross actuator gain turned up too far.

2)Its real clear that they switch modes on the descent, IE the vehicle it goes into tight position hold mode, the engine then starts moving a lot more.

In any case its cool to watch the videos.

Congradulations to Masten.

Congratulations to Masten. They did as good a job as is likely possible.

Their preliminary average landing accuracy was 15cm so based on my understanding of the rules we would have to have an average accuracy of 4.9 cm to beat them The vehicle reference point can move 5 cm just depending on how it settles on the gear. That is impressive.

To Tie and split the purse
we would need an accuracy of 25.9 cm or better.

On Monday I stopped by their shop and got a look at their L2 vehicle (I think I can now say this publicly as they have now published a picture of it) it's very light and looks largely complete. They probably just have to bolt the engine and electronics from xombie on it and they have a real good shot at Level 2.

All in all a very discouraging week.

Tuesday, October 06, 2009

Monday, October 05, 2009

Testing 1..2.. smack

We flew twice today. We smacked the forklift again, we are climbing too high , its now jumping off the ground going to the proper altitude sitting there for awhile then slowly ever so slowly climbing up up and away. I need to spend some time reviewing data and trying to understand whats going on.

On the last abort we smacked the forklift and tore off a landing gear.
We were really hoping to get some in flight performance measurements.
No such luck. About all we know is that its performance is better than the blue ball.
Is it enough better to do 180 seconds? That's the $1M question.

We will probably go out again Wednesday night or Thursday morning.

We were testing some new wide angle video and while the picture is not perfect (Its facing the sun) we got some really spectacular smack the forklift video. (The HD stuff takes to long to process on the computer I just don't have time.) This post was written in the car so the MiFi is working while enroute, and the laptop just does not have the cajones to edit video.

I'm really looking forward to Nov 1st.

Saturday, October 03, 2009

Testing again...

All tested and ready to go. Were on the way to FAR once more.

In reviewing the video of the last flight I was not really happy with it,
it was stable, but did wallow around more than I'd like. So I did a through review of the code and the adjustable variable settings. I found an error in my integral position gain. In my loop code I'd transitioned from having the displayed integral constant be the proper value or a percent value.
I'd set the value like a percent and used it as a normal so the itnegral gain was 100x too high.
This makes me much happier as the flight visually looked like an earlier blue ball flight that had the same problem. The code set started on the helicopter and transitioned to the blue ball and from there to the silver. I've tried to put all the vehicle specific stuff in a separate compilation modules, but the code has now drifted so I have three similar but not identical code sets.

I Started out with everything under CVS on my main computer with updates from the laptop. Then the laptop died and code was moved to the backup laptop in the field and the CVS stuff has not caught up. The project always has the dilemma, stop and fix a systematic problem where it effects your productivity, but not the actual flight vehicle. 6 months ago these decisions were easier, now it's will the time taken to fix "This" have a payback in the next 27 days.

I'ts pretty clear that the "2nd" gneration is better than the first. The Blue ball is our 2nd gen vehicle, the silver is gen 2.5. We have lots of things we know we would do different on gen 3, yet the current plans for gen 3 add the whole aerodynamics aspect that is missing from the LLC vehicles.

Thursday, October 01, 2009

Driving home again...

We tried one hover test this morning about 11:45 am. The vehicle was stable, but we continue to have vertical throttle control issues, as it climbed above the fork lift then aborted when the ropes jerked on it hard enough to exceed the tether tilt abort limits. This happened simultaneously with my hitting abort. Luckily we missed the forklift and did no physical damage. The pressure readings were being erratic all morning and after the flight we did some debugging and one of the transducers shorted, taking out the A/D converter and letting out the electronic magic smoke. Putting short protection on the 4-20 ma transducers has been on my "I really should do that some time list". I guess it will be friday. So if all goes well we will be doing the 4 hour drive again on Friday night.

After determining that the vehicle was not fixable in the desert, we also received a delivery of propellant and decanted that from drums to smaller poly totes. Right before sunset we flew the helicoipter with the full RTK gps stuff running. Much more accurate, Seems to be more stable, but we ran out of light so we will test that more this weekend.

Its 9:30 PM we are 2:45 min from home (my son is driving), I'm on the web with the new MiFi wireless access point. It does not work at the FAR site, but works on the road to and from. In the past its always been that both my son and I wanted to drive as being passenger was really boring,with live internet access now the other eway around as the passenger can surf,,,, I think I'm going to go read the Firday XKCD.

Wednesday, September 30, 2009

Going to try again...

We are leaving for the Desert/FAR about 6pm tonight.
We hope to hover the silver ball and get some performance measurements.
We will tweet results, we may post from the site in the evenings if our new MiFi works from there.


Monday, September 28, 2009


It is very possible that there will be prizes determined by accuracy this year. I've spent the weekend working with the high precision RTK GPS and the helicopter.

If we can do the 180 seconds (big if) then I'm pretty comfortable beating the rumored 0.8m accuracy of Armadillo, beating the rumored 10cm accuracy of Masten is going to be a lot harder.

I still have a fair bit of work to do, but it looks promising. I'm not going to say much more about this as I don't want to give to much away. The chalange is in the vehicle dynamics, not the GPS.

Any sufficiently advanced technology is indistinguishable from Magic. Multifrequency RTK GPS stuff is sufficiently advanced. When you realize your making sub 1 cm scale measurements over a 20000km distance in real time at many Hz it is stunning. That is 0.00000005 percent. or 0.0005 ppm.

Thursday, September 24, 2009

Testing Results, mostly good...

For the next 36 days Updates will be short and probably not include much video or pictures, they just take to long to edit and prepare and I'm out of time.

We static tested the silver ball today, on the first static test we were expecting bright orange hydrocarbon flames(We were running gasoline as the fuel) . The exhaust was clear loud and steady. We though the fuel valve did not open and made some minor changes to the static test software refilled with peroxide and ran it again....

During the second run again clear loud steady rocket exhaust, but again no expected orange,
although about 10 seconds from the end of the run there was a noticeable change in the exhaust note.

On closer inspection the fuel tank was empty and there were signs of light soot on the thermal coating in the motor. Based on the run time and amount of fuel we loaded the pitch change at 10 seconds from shutdown would have been when we ran out of fuel. This is the first gasoline fueled motor we've ever seen fired so its possible the only thing wrong was our expectations.

We switched from kero to gas for more volatile fuel and slightly better (1 or 2 sec) ISP.

Given that we then prepared to try a tethered hover with the gimbals, and we ot bitten by small details. On the blue ball the only vent is the emergency vent we fill through the vent and have never had problems. On the silver ball during fueling for the two static tests the purge vent had been open from the main tank utalage to the motor. Before fueling for the potential tethered hover we closed that vent so we could slightly pressurize the vehicle, hang it and see if the roll control thrusters were working correctly. (They were) this caused us to leave the purge vent closed. Since the blue ball has no such vent we did not think it was an issue.
We put the fill tube down the vent with lots of clearance and started pumping.... a minute or so into the fill the hose comes flying back out and sprays everything with peroxide. We immediatly douse the vehicle, and perople with the standby water. This water deluge prevented any real damage, but also caused some of the electronics to be glitchy. So we called it a day and brought the vehicle home to dryout and test the wet parts.

The reason this happened is subtle, the main vent attaches to the tank with a 1.5" Sanitary fitting. A 1.5 inch sanitary fitting is very similar to a 1" sanitary fitting, ie they are identical other than the hole in the middle of the gasket. We had put a 1" gasket on the 1.5" vent. So when the 1" fill tube is shoved down into the vent it seals with this gasket.

Now that I'm home I will review the data in detail and look at the video.

Wednesday, September 23, 2009

Leaving for Test Site within the hour...

We are going out to static test and maybe over the silver ball.
News when we return.

Tuesday, September 22, 2009

Unreasonable Souvenir.

Garage Space is always at a premium. We usually take broken parts to the scrap metal dealer once a month. Since the rocket and camera died in such a fun way we thought we'd sell the pair on e-bay as a souvenir.

Also here is the promised picture of the silver ball in all its glory....

Silver Status...

I finished the integration testing on the Silver ball last night.
the GPS cable turned out to be an intermittent antenna problem.
Swapped out the antenna and all is well.

We ended up about 30lbs over the target weight, at least 10 of these pounds are in the new stainless motor. In the present condition using carefully calculated ISPs adjusted for under over expansion we get a hover time of 182 seconds. we never ever get theoretical ISP, so we will need to do something. Most likely a careful weight diet and the addition of some external pressurization so we can fill past 50% point. If we fill the tanks till we have a takeoff Thrust to weight of 1.2 I get a hover time (using our historically achieved ISP fudge factor) on the order of 200 seconds. Some Parts like the Motor are really massive,....

Some parts like the roll control thrusters are as light as I can imagine...

We hope to test this coming weekend.
If I get home before its dark today, I'll drag it out in front of the garage and try to take an overall picture of the beast.

With the blue ball the "vector" point for the vanes is on the bottom of the motor so that there is always an offset from this point to the center of gravity ie CG. With the silver ball this point is the gimbals hinge and with the heavy motor we were worried abut the this getting too close to the CG, so we mounted the payload up high, since we mounted it up high. The (easily removable) leg weights we use on the blue ball won't work. The silver payload are steel blocks bolted to the top of the vehicle. This combined with the increased weight makes the silver ball a lot harder to move around. My son and I can still carry it, but we cant lift it 3 feet in the air to put it in the truck without assistance.

I've done some thinking and calculating. If I leave the system as blow down and do all the weight reduction things I can think of its still pretty marginal. If I put a pressurization system on the vehicle I can add 30 more pounds and get 75% of theoretical ISP (This is 0.75 * the number beyond already accounting for over/under expansion etc...) and still do the task.
If this weekends test goes well it looks like engineering a pressurization system gives me the most bang for the time invested. It has the side effect of almost doubling my propellant usage and that makes my propellant supply look tighter than I'd want for through testing, but it still looks like the best path.

A side note on calculating ISP for over or under expansion...

For under expansion I just use the ISP I calculate when the chamber pressure is exactly right for proper expansion, thus I get no ISP credit for the actual higher chamber pressure.

For over expansion I take the theoretical ISP for perfect expansion at this pressure, then calculate the area difference between the actual expansion cone and the perfect one. I then calculate this difference in area as a thrust equal to the (ambient pressure * this area).. in the wrong direction and use tht as a reduction in ISP.

I have some C code that will run propep as a sub process and can make these calculations automatically. So as an excercise I varied the actual expansion ratio up and down searching for the flight performance maximum. It turns out the simplifying assumptions I made in January 09 blog post of using the average flight chamber pressure was withing 1% of the more rigorious method, well withing the uncertanty in all these numbers.

Sunday, September 20, 2009

Beaten by a cable...

I expected to take the silver Ball to FAR on Friday.
I've worked for 18 hrs a day for three days and I'm still 3 hours away from being ready.
I think I have everything working except the GPS.

On The Blue Ball the GPS antenna sticks up and we've broken it off three times. So on the Silver ball I machined a real light aluminum dome that sits on top of the computer cover and the GPS antenna sits on that. It all lines up so it goes directly into the RF tight box the GPS lives in.

Nothing sticking out to break off.... alas every time you open or close the computer box you must unplug and replug the GPS cable. After opening the box 6 million times over the last few days the cable died. If I replace it with a different cable everything works, alas the mechanical fit is such that I can't assemble things with the different cable. We've passed all our integration tests except the last one a simulated takeoff, we can't do that without a GPS lock and no antenna == no lock. I could go and do a static test, but I think I'll wait a day or two and try again. I've been pushing too hard and I'm too tired to think clearly not the right state to be in testing a new system.

One of these days I will learn how long it takes to do vehicle integration.
When you have a pile of individually tested and roughly rocket looking parts you think you have 4 hours of work, alas its days or weeks of work, not hours.

Tuesday, September 15, 2009

Congradulations to AA and good luck to Masten.

AA flew the 180 last week, and Masten is going to attempt the 90 second flight tomorrow.

I think that the 180 second event will be a stretch for both Masten and Unreasonable.
The 90 second event may come down to who has the best GPS equipment.

Toward that end I've recently purchased a pair of Trimble BD960 L1-L2 Glossnass RTK Rover and Base GPS units with all the accuracy enhancing options. I also got what I consider to be a very favorable ruling on from the judges on what can be counted as payload weight.

I've been flying with a very light L1 GPS from Crescent, its a nice GPS, and flies well,but as a L1 GPS its just not accurate enoough if the prize will be won or lost on GPS accuracy.

So I asked the judges the following question:
If a camera is carried and used to enhance landing accuracy, can it be counted as payload?
(The history here is yes it can be payload)
Since a GPS position reporting is also part of the required payload can I carry a 2nd really accurate GPS report its position for the payload requirements and manually use the information to correct my posiition, just like a camera. I expected them to rule that cameras used for landing accuracy could not be counted as payload, instead The answer I got back kind of suprised me, yes the 2nd GPS can be payload as long as it is not required for flight, and it does not matter how the data is communicated to the vehicle. So it can even be automatic. you might think that this is a lot of fuss over a few ounces of electronics, but to get really really accurate GPS you need a good survey grade choke ring antenna, a good one can weigh as much as 12 pounds or more.
Now I can count that as payload!!!!! This should give me accuracy in the 2cm range, if only I could control the vehicle that tightly. I've started working on that with the helicopter a so far I'm consistently better than what armadillo reported for accuracy on their flights. how much better I won't reveal until the end of October.(The Helicopter can't carry the weight of my really good antenna, so I'm using a lesser antenna hence the vehicle should be at least as good.)

A sobering though is that it would be possible to accomplish both the 90 and 180 second tasks and still walk away from the competition empty handed. If Masten,Unreasonable both accomplish their goals, its very likely that one of the three teams will get nothing.
For example:
Masten, Unreasonable and Armadillo all do the 180.
Masten and unreasonable are more accurate, Armadillo gets nothing. That is clearly the least likely scenario, but anything is possible.

Two years ago there was one team attempting and no winners.
This year its a real possibility that all the prizes will be won with more successes than winners.

Also today was the last possible day to register for the event, so we should also hear from Xprize in the next few days to learn if there are any surprise teams registering at the last minute.

Sunday, September 13, 2009

106 Second Hover

We did a 106 second stable hover with the blue ball.
We also started working on the PAD forms for the LLC pads.
More info later...

Also started tweeting as unrocket

Will probably keep that up until the contest....
47 days and 6 testing weekends left.

Wednesday, September 09, 2009

Working on Rockets...

I've taken the week off from the day job to be Unreasonable. I finished the last of the machining on the new stainless motor, I picked up the chamber liner from flame spray and now all the parts are at the welder. I received all the turned stainless parts today, so I have spares.

To finish my earlier discussion about sending parts out I talked to the vendor and he actually did not have any scrap. All his problems or issues were found in dry runing the programs on his CAM software, so no scrap generated.

The Blue Ball software is ready to test again, we may do so this weekend.
I've still got to get the video working correctly.

51 days and 7 testing weekends to go.....

Sunday, September 06, 2009

Mixed Results....

Good news:
The goal for this weekend was to resolve the "heavy wiggles" and fly a clean 90 second tethered flight. We resolved the wiggles and we flew a flight somewhere between 89 and 91 seconds.
We had significant takeoff throttle margin so I can add some more propellant and I'm sould be able to get to 95 or 100 seconds.

Bad News:
Our wireless video system did not work, it looks like the cable coming out of the video camera was intermittent. We did not have wiggle problems, but we had roll, or yaw problems holding a consistent heading. We actually "spun" to the point of the tethers winding up and forcing an abort on a flight. We tried to fix this 4 times and nothing we did had any effect.

After we got home and I reviewed te code, I learned it had no effect be cause the variable set up to be "Rudder" gain was not connected to the loop controlling the "Rudder" (Remember this software was developed on a helicopter and hence has helicopter type coordinates rather than more typical rocket names for the axis.) so I could turn it up to infinity and it would still do nothing.
So we need to try the test again next weekend.

Scary News:
We have 7 more testing weekends and 53 total days before the event .

Friday, September 04, 2009

FAR FAR Away again...

I just finished packing for a trip to FAR on Saturday, we will be attempting a 90 second tethered hover with the blue ball. This includes the live video so all the rules requirements for the vehicle are complete. Other than resolve the heavy weight stability issues we have no more fabrication
to do on the blue ball.

On the Silver ball I finished slotting the stainless chamber and machining the injector plate. Both parts were dropped off to be flame sprayed with a thermal barrier coating today.
(Last time I went by the flame spray shop the gave me a quick shop tour and it looked like there were a bunch of merlin sized chambers in there to be sprayed.

I also dropped the next set of catalyst screens off to be plated.

Next week if all goes well the silver ball will be hardware complete.

Tuesday, September 01, 2009

My weekend with the Stainless Bully...

Team Phoneicia's blog had a quote Aluminum is your friend stainless is the sadistic bully from third grade. The part above has not been cleaned up yet, but its basically done it started out as a 1" thick 8" diameter 316 stainless. The back side is taped for the nozzles, all I have to do is clean up and drill the holes coming in from the stubs sticking out.

Tuesday, August 25, 2009

Flight Dates...

I can finally be public about our flight attempt dates.
We will be flying the last two days of the contest.
October 30 and October 31st at FAR. This gives us the maximum time to prepare and guarantees that we know what we are aiming for for given any tie breakers.

You can see the Xprize press release here
(I could not find it on the xpf site so I linked to Space transport news instead.)

Some notes on the other dates:

Masten has reserved October 28,29 so that means any not-yet registered teams could
fly on the 26t/27th in the Mojave area or earlier else where.

This in effect moves the registration deadline for any other teams up to
September 9th or September 12th

If Armadillo fails on the 12th-13th they can register to try again and just sneak in under the time window. In talking to others it somewhat clear that Armadillo choose the latest date that would allow them to try again.

Thursday, August 20, 2009

Rocket parts and fruit

In spite of the whimsical picture and title this is a serious post.
I can make rocket parts, or I can buy rocket parts. I can grow my own fruit or I can go buy fruit.

I design embedded electronics as my primary profession. When I first started I built elaborate breadboards and test circuits, I even played with etching my own PCB's. Now I order pcb's from the prototype PCB vendor for everything. Even test circuits. What changed?
I'm much more experienced and my designs have a lot more experience behind them. I've learned what works and what does nott I can read a data sheet (including what is not in the data sheet, often the most important part.) I've also learned that spending the money getting a proper prototype PCBs and assembly is a more cost effective use of my time.

At home we have a peach tree, it grows wonderful peaches to the point that we are all tired of peach pie by the time it drops the last peach. There is a sense of satisfaction from growing your own. All the rest of our food we purchase.

When I started working on rockets it my attitude was more hobby and satisfaction from doing oriented. You can see from the old blog posts we built valves, gearoxes and even weird tanks.
As the project has matured and we've started actually doing work for customers I'm starting to realize the value in off the shelf stuff. My attitude is becoming more business like.

For a number of years now we have been sending drawings and material to thunderbird waterjet here in San Diego and having them cut out parts. We had the hemispheres for our tanks spun by AMS industries. Yet the vast majority of our parts have been fabricated by us for us. We don't generate elaborate 3D models and then fabricate the parts, we build a little, scratch our head and build some more. If we did not have in house machinging capabilities it would significantlyy impede our progress, having to wait for an outside vendor to fabricate every bracket and doodah would take forever. I think this lack of inhouse capabilities is one of the things that has slowed Masten down. Yet fabricating everything in house does not make sense either . Some things like the regen rocket motor I documented on this bblog were fabricated in house from detailed drawings. I think that was an error. I'm in the process of fabricating a new regen motor from stainless. I sent the drawings out for quote on MFG quote and was astonished at the price quote I got. The stainless part among the fruit is the first signifcant custom part we have not fabricated in house. Several more parts of that assembly are due soon. I can't imagine the nightmare of machining that part out of solid stainless, yet the vendor did a really good job for a very fair price. (I'll talk more about the vendor and ordering process when I get the full set of parts, so far I'm pleased.) One of the down sides is that our welder is going on vacation for 10 days and the ordered parts are going to just miss his departure, so we won't be testing much for about two more weeks.

Its not always easy to know what to build and what to contract out, I think its really important to have in house fabrication skills and equipment, but I also think we have erred in not sending more work out.

A final question for the peanut gallery, I'm 90% sure the vendor making these parts underbid the job. They had a couple of programming problems and probably scrapped more metal than their profit margin. As a business man I feel strongly in win win arrangements with vendors.
If the business is not win win then eventually the vendor won't be there next time you need him. Would you bring this up with the vendor and offer to cover some of their loss?
(Clearly by the terms of the quote I don't have to)

Saturday, August 15, 2009

Another Long Day.

The Day Started at 5:30 I spent the first hour planning my weekend. the next hour I laid out the parts and peices for the days and figured out what I was missing. Then I was at Marshals Industrial hardware store at 8:am and the IMS Metal supply at 8:30.
... Its 10:30 PM I'm done for the day.

I Fabricated two beefy bearing holders and gearbox adapters for to the ball screws that will be the gimbal actuators on the silver beast. I also machined the ball screw ends and made a planetary spider to ball screw adapter. Its going to be a light, strong, fast and brush less gimbal actuator.
They are about 1/2 the weight and cost of the bug actuators everyone else is using. (assuming my time is worth zero, any realistic valuation of time and there insanely expensive.)

I also spent about 4 hours at Flometrics testing injector concepts for the Bi-prop and Steve an I built a flow visulization test setup. Many thanks to Steve! We used Flometrics Pistonless Rocket Pump as the drive the injectors, we could dial up any pressure from 50 to 400PSI and it just worked. It was flawless. Some of the misting spray nozzles have a maximum pressure, we discovered that one of the tested spray heads had unstable flow above its rated pressure. It was a swirl nozzle and it had cavitaion where the flow was really erattic. That was about the only real supprise everything else tested as one would expect it to.

I'll post some pictures of the tests. Sunday I hope to turn what I learned from the testing into a set of drawings to Fabricate the injector. I also ope to compeltly finish my actuators.
It was nive to spend the weekend making stuff rather than driving out to the desert/FAR.

Thursday, August 13, 2009

Why Space Matters

Why does space matter?

I'm lucky in that I was born in the united States. Our family has multiple cars, a house to our selves, more food than we should eat. Our standard of living by any real measure is better than any group in history. The United States has about 5% of the world population and consumes about 30% of its resources. Personally our family is probably above average in resource consumption even for US citizens. So I'm going to ask and answer a series of questions.

1)Are citizens of China, or Sub Saharan Africa inherently inferior to my family?
NO they are not,I believe all humans are born with certain inherent value.

2)Do they have a right to aspire to what I have.
Yes they do.

3)Do we think that global terrestrial resource production can be increased 6 fold from what it is now?
No I don't think that is reasonable outcome.

4)Is there any process where U.S citizens will voluntarily reduce there standard of living by a factor of 6. No I don't think that will happen.

5)Do we the U.S have the right to use force to prevent others from having what we have?
No we do not.

6)Will some combination of conservation and increased production create a factor of 6 when adjusted for the ongoing population growth in the world?
This is the option that all the traditional "Greens" or environmentalists are betting on. They naturally feel that if we just cut back a little bit everything will be better. I just don't see it. It is such a violation of natural human striving tendencies I can't see getting to a factor of 6.

So unless you want to change the answer to one of the 6 questions above "we" the population of the world are in a no win scenario. Some things like good batteries and low cost fusion power could help significantly, but its not enough. Just imagine how much steel it would take to give every family on earth 2 cars? (Recent studies have shown that mass transit when fully accounted over the life cycle of the system are just as resource intensive as a small Car. )

Where will the additional resources come from?
Where can we do dirty industrial process where we don't soil the environment?
Where can we find unlimited energy?
Unlimited expansion space?
Unlimited metals?
Unlimited Organics?
(Don't nit pick Unlimited in this context means several orders of magnitude more than we have now)

The only two answers are a 6 fold reduction in earth's population or expansion into space.

We are spending trillions on the assumed option in question 6 and simple math shows its not possible. Where are the trillions helping us expand in a way that can work?

Just something to think about....

Sunday, August 09, 2009

Thats why we test...

We tested again Saturday. This was the first time I was responsible for the FAA notification and not just piggy-backing on the FAR standard waivers. The Airspace at FAR is interesting. From ground from ground level to 1200 feet AGL we are in uncontrolled airspace. From 1200 ft AGL l to 18000 ft MSL we are under the FAA jurisdiction, from 18000fto to 50K ft we are under the jurisdiction of the Edwards 2508 restricted area. Since I’m under 1200 ft AGL for tethered (or free) flights I don’t need a waiver or authorization to enter controlled airspace. Since I’m not entering controlled airspace. Yet the new FAR 101.27 requires I notify the nearest ATC facility between 24 and 72 hours before the event. A lot of the stuff flown at FAR goes above the 18K limit so when I asked FARS primary Pyro op who to notify I was given the 2508CCB contact. They did not want the notification because we aren’t in their airspace. When I called the loacal High Desert ATC facility

ATC: how high,
ME: 45ft
ATC: Why are you telling me this.
ME:Can I have your Fax number.
ATC:Here it is xxx.xxx.xxxx
ATC:What am I supposed to do with the document your faxing?
ME:I don’t really know I just know I have to send it to you. It does not effect your airspace were chained to a 10000lb forklift.
ME: FAR 101.27 says I have to tell someone. I’m crossing my t’s and dotting my i’s.
ATC I see.

So I faxed the notification required of 101.27 to the High desert ATC facility.

A few weeks ago our FAA representative asked if he could come out a watch us fly so Wynn came out to observe our flights and flight preparation. We were all setup by 9 am and were attempting to do a 90 second Tethered hover. We had never successfully flown at that weight. We didn’t do it on Saturday either. You can see the heavy takeoff video here our vehicle is VERY light without payload or propellant we weight less than 100 lbs. Since we are using a low performance propellant so we need a lot of it so our weight with payload and full fuel is about 400lbs. This means that we have a 3:1 weight change in flight. From the video its obvious that with a 3:1 weight change we need to do some gain scheduling as we had plenty of thrust, plenty of control authority we just weren’t stable. We continued to do short hops until we had dissipated enough propellant to fly stably. We eventually got an absolutely perfect 65 second flight but that happened after the one remaining video camera ran out of battery. So no video. We will try again soon.

I think that Wynn (our FAA rep) was impressed with how remote the FAR site is. You just can’t get a feel for how remote things are by looking at google earth. Standing on site and seeing the total desolation in every direction gives you a better feel. I think Wynn enjoyed the show, I’m glad we got at least one successful flight off for him.

Thoughts on the stability issue: With a gimbals system the forces generated by the thrust vector scale directly with the motor thrust. With vanes the relationship is not so clear as one increases thrust one increases the density of the gasses within the cone that the vanes act in. So its not clear if the vector forces are linear with thrust (thrust is a good stand in for weight and a marginally good stand in for rotational inertia) or if they increase or decrease? Looking at the video this looks a lot like earlier problems where the differential gain was too high. I don't really know if I should just lower all the attitude gains or if I should vary the P,D terms differently.

I have not yet reviewed the data, I hope to do so this week.

I also added another wiggles video from onboard.

Saturday, August 01, 2009


Friday was propellant day, I was out at FAR all day.

  • I received an order of 85% from XL Space.
  • I built the forms for the base of the generator that will complete my processing facility.
  • I fixed a leaky valve on the safety water supply pump.
  • I built a frame to hold the Refrigerated air dryer up on a shelf off the ground to give more floor space.
  • I cleaned up around the site a little bit.

One more long day to finish my processing facility and I’ll have three sources of propellant.

180 second status: I’ve put together both an order and a RFQ for stainless versions of the regen biprop motor to replace the dead aluminum one. After examining the dead motor its really clear that something bad happened in the region of the pressure port. It was more than a a bad weld. We either had the port through the wall leak fuel rich stuff into the cooling jacket or we have some kind of contamination there. On the next motor this is going The new motor will have an uncooled section thats identical to the top of the blue ball motor and will weld to a cooled lower section. There will be no joints through the cooling jacket wall.

Realistically we get one more shot at the 180 second motor and the way rockets go that has to be considered a hail mary.

Tuesday, July 28, 2009

Observations from the fireing

As shown in the camera death video we ran the H2O2 Kerosene motor last weekend. The chamber pressure port failed causing local loss of coolant and subsequent failure.

Even with the short run it answered several questions I've had about H2O2 Kerosene motors.

The Motor was built around 3 1"x  7" metal monolith platinum coated catalysts.

This gives it a large contraction ratio 7" to 1.9" . It was also designed with an L* of 60.

Test conditions:
~200 PSI chamber pressure.
~ 6:1 O:F by weight
90% H2O2


From the previous mono-prop runs its clear the cat pack is not working very well The metal monolith seems like it needs finer channels.

Even with a partially working cat pack ignition was almost instant. Reading the available literature ignition seems to be a strong function of  contraction ratio.

One of my personal questions was can you run an H2O2 motor like a traditional bi-prop where the peroxide is thermally decomposed in the chamber?  With a generous L* of 60 and contraction ratio of  almost 4 at a chamber pressure of 200 psi the answer is no.  There was clearly undecomposed peroxide in the plume.

Sunday, July 26, 2009


This camera gave its life to provide you with this video.

Monday, July 20, 2009

3 Months to go and beyond.

The 2009 NG-LLC ends on October 31st, just over three months from now. Seems like a long time but it will go by in a flash. This week I’m cleaning up the blue ball  removing some excess wiring, freshening the cat pack etc. If all goes well we will try a 90 second Tethered hover on Saturday.

I think we can be ready for the 90 second flight before the deadline. getting ready for the 180 second flight will be harder. If the current silver ball does not have the necessary performance we are basically done for the year.

What happens after 2009? If the any of the 180 second prizes are un-won we will obviously attempt that. Beyond that we want to work toward a reusable sub-orbital vehicle.  Anything that can do the 180 second flight should be able to get to over 100K ft with just a tiny bit of Aerodynamic cleanup. Or success of failure at claiming the prize $ will set the pace on that effort.

Looking forward low cost access to space is a civilization changing event. Today you have a few well funded efforts in that direction SpaceX Blue Origin , Virgin Galactic/Scaled. You have a bunch of bootstrap organizations, Armadillo, Masten, Xcor, JP Aerospace etc... You have a few that failed along the way, Kistler, Beal(I really like Beals technical approach), and some that were absorbed into the edges of traditional aerospace such as  orbital.

  As a somewhat successful business man  with a passion for space I’ve burned a lot of hours thinking about how to build a space company that makes business sense.  It is a significant chicken and the egg problem. No matter how well thought out my business plan is no one is going to hand me a 100M blank check to go chase after spacex.  Yet without real commercial market driven, bare knuckle no holds bared competition in space access we are all stuck on this rock.

  It may be possible to slowly build up and bootstrap a company from marginally profitable sub-orbital to something orbital, but it will take tens of years and I’m just not sure I have the energy to put 200% into this for that long.  On the flip side I don’t see anything else that is really worth doing. That dilemma, understanding the magnitude of the task and at the same time seeing it as a truly worthy task actually has me a bit depressed.

Some days I see the people sitting on the beach with a beer in hand and ’m jealous, other days I see that as a waste of human potential. My wife thinks this whole project has driven me over the edge from committed to obsessed. What can I say, I’m an unreasonable man.







Monday, July 13, 2009

No Strings Attached

(Thanks to Kevin Baxter for the Photo)
The Landing was perfect, more later in the week once I recover from the 111F days in Mojave.
Video onboard
A Video from Ben Brockert
VideoFrom the ground.

Thursday, July 09, 2009

Going to FAR

Just finished packing for an early AM departure. I started the day at 4:45 its 11:21 I plan to leave at 4:00 am 18+ hours, . I’m tired.

We have four major projects for this trip in order of importance.

  • Large Customer Project that dwarfs the other three.

  • Static fire H2O2/Kerosene silver ball.

  • Tether fly blue ball. (If this goes really well might try first free flight)

  • Work on Propellant Production.

There will be a TV crew on site Saturday and all the FAR regulars have been asked to bring their best “show and tell.”






Monday, July 06, 2009

The ... is connected to the ...

My basic control loop is as follows:

  • 1)I have an actual and  desired position.-> I use that to generate a desired velocity.

  • 2a)I transform the desired velocity into a desired right and forward velocity with current yaw/heading.

  • 2b)Transform the actual velocity into right and forward velocity with current heading.

  • 3a)I use  actual and desired right /left velocity to set desired roll* angle.

  • 3b)I use actual and desired forward/back velocity to set desired pitch angle.

  • 4a)I use the actual and desired roll angle to set the aileron or actuator position to cause roll.

  • 4b)I use the actual and desired pitch angle to set the elevator  or actuator position to cause pitch change.

I reality steps 1,3 and 4 are PID loops(proportional integral differential) , I’ve been running for a while with  Step 1 P,I step 3 p and step 4 pd. For hovering this works just fine as what I really care about is holding position. Any bias in the system is taken out with the integral term in the position hold. When I start navigation from place to place that does not work so well. It’s beginning to look like I need properly distributed I and D terms on each loop. For example a helicopter does not hover with the frame level, my current helicopter hovers with a 12 degree to the right and 5 degree nose up from its resting position on the skids. I could carefully tune the centers of all the loops so these biases don’t effect the control laws, but they seem to vary with somewhat randomly.

I’m in the process of trying to change to 1:PI,3:PI,4:PID as I get each loop under control I have to turn down the gain in the outer most loops as the gain was cranked up there to handle the biases not taken into account with the integral terms.   I have a simple utility that runs on the laptop and allows me to tweak gain constants without recompiling things in the field. It also allows me to assign one constant to a trim lever on the RC transmitter for tuning. I’ve flown  about 30 times in the last week trying to get all this sorted out on the helicopter.  I’m going to have to tune the rocket as well, but hopefully I’ll be more efficient with that after learning on the copter.

I started with 10 variable slots, and have now moved to 16 variable slots. I was having a hard time making sense of it all until I discovered today that when I did a cut copy and paste on the UI that sets gains, the channel being assigned to the “trim” lever was the wrong one, olny  if I was trying to set one of the 6 new channels, so the trim lever made things change, but not what I though it was making change so it was all very confusing arghhhh…

I’ve fixed that tonight and I’ll try again after work on Tuesday, or maybe not, I’ve been reading some David Weber snipits aka “book crack” and amazon tells me the book in question has been shipped and I will get it on Tuesday. no more rushing to the site to see the latest installment on Mon,Wed,Fri ;-)


*Since I started on a helicopter I’m using that coordinate convention, where what is typically done for rockets is to call “roll” rotation around the nominally vertical actuator.

Sunday, July 05, 2009

NGLLC news etc...

Several items of interest in the NGLLC news. Masten Space has announced they are  planning both a Level 1 and Level 2 attempt, and Armadillo flew the super Mod for 178 seconds. It looks like there are presently three teams with flyable vehicles in active testing. It should be interesting.

I’ve spent the last week working on navigation and control with the helicopter. I’ve been chasing things like the natural frequency of the rotor interacts badly with the Z axis accelerometer for some interesting aliasing. (The vibration on the rocket looks like white noise, the vibes on the helicopter don’t.) I’m also working to improve the navigation accuracy as that will be key to winning if there are multiple successful LLC teams this year.

This coming weekend the 11th we will be out at FAR and hope to fly the blue ball and static test the silver ball again. I think this will be a big FAR weekend with a number of interesting things going on.


Saturday, June 27, 2009

Propellant Progress..

It looks like we have secured another source of 50% peroxide.

The process of turning 50% food grade into 85–90% rocket grade is as follows:

1)Filter the peroxide through ion exchange resin to remove stabilizers.

2)Sparge from 50 to 70%

3)Sparge from 70 to 85%

Step 1 needs to be conducted with the bulk temperature below 70F or the resin tends to catch fire. The low temp at FAR is presently >70F with a high > 100. This leaves the bulk peroxide temperature too hot.  So we took a dewar of Lquid nitrogen out to the desert and cooled and then filtered about 1500lbs of peroxide. We cooled the ulk peroxide by bubblin Ln2 throu from the bottom. We started at 11PM and finished about 6:30 am just as ths sun was comming up. Everything worked exactly as desined and according to the TDS meter we removed the bulk of the stabilizers.  We got back home at about 11:30 am this morning. Its just after 6pm and I just woke up. This all nighter thing worked so much better 25 years ago in college.

We have about 30 minutes more work and we are ready to try step 2. We will proably do this next weekend. I can’t do the final step until the generator I ordered arrives. The 50 to 70% step can be done with filtered “desert” dry air, the 70 to 90 step needs the air to be dryer than that and our big oiless compressor and -100F due-point airdryer system needs more power than we presently have on site.

Saturday, June 20, 2009

Wind blown and dried out

Just got back from the desert. I spent two days on site at FAR, I went out Thursday night, I was there to help unload some deliveries of steel and concrete block Friday Morning.  The deliveries are for new viewing bunkers as the existing viewing bunker has been over full and crowded for a couple of recent launches.

I also got 3000 lbs of 50% peroxide delivered. I think I’ve resolved my propellant supply.

I spent most of the day Friday working on our refining equipment. Saturday was a general FAR work party.  I’d hoped to run the first de-ionization steps on the new propellant, alas it was really hot and the temperatures were just too high to do this safely.  I’d also hoped to fly the blue ball under tether but it was too windy. I did fly the helicopter in 25+ MPH gusty winds and it did just fine.

I spent two full days working hard and accomplished one of my three primary goals for the trip. There are always lots of secondary goals to accomplish. Often simple things like: we now have 5 large  bottles of compressed nitrogen on site and I had no way to tie them all down properly. I’d been laying the bottles on their sides. Now the bottles are standing up and properly restrained  to the container wall.


Monday, June 15, 2009

Things that work are important.

This project is a big project and its important to have some success along the way.  Its easy to get mired in a bunch of problems such that you experience no successes that you can celebrate.

So in a project this large its important to schedule small successes to keep the motivation up while you slog through the details of 10K things.

I went out and flew the helicopter again tonight. For the first time I turned on the integral term in the gps position hold. It made a huge difference. A helicopter flies with a slight tilt, the tilt is such that with purely proportional position gains it has to build up some error to stop moving. Then it also moves around as the wind changes and the proportional error grows to the point to counter the wind.  I’d been doing: Start where you are, climb vertically, hover for awhile and land.  I also like to be behind the helicopter when playing safety pilot as its easier to stay oriented and try a save if needed.  Well it just so happens that in proportional mode every time you do one of these cycles the helicopter backs up and to the left about 2m. Do it 5 times and you have  moved off the edge of the field and over the embankment. With the integral gains turned on I flew it 6 times and the final flight landed within 8 inches of the original take off point.

Its cool when everything works. I also fired up the helicopter flight data review system and it just reminds me how much detail work has gone into this project:  (The position hold accuracy plot is uninteresting as the errors are so small the lines look straight, so here I show the auto takeoff.)

Click on the picture for a bigger view  and you can figure out where I test ;-)


Sunday, June 14, 2009

Some updates

When I started this project it was really fun. Its now been almost three years and its gotten a bit more serious and not as fun.  I’ve got the perpetual internal battle about do I lighten up a bit and have more fun, or do I drive to completion with the thought that I may eventually be able to monetize what we have done. I don’t have an answer, but the struggle is still there.  One runs a risk turning something you enjoy doing into a business. Will you still enjoy it when its a have to?

Long time followers know that we started our software development with an RC Helicopter. Then we ported the software over to the blue ball and did some hovering. While a hovering rocket is cool the LLC task requires more than hovering. We need to navigate and sequence through the 3D way points with time delays etc… We also need to be be able to soft abort  allow some manual steering to try and hit the exact target. Its much easier to develop this stuff on the helicopter that does not require a 4 hour trip to test. So Today I spent the day putting the helicopter back together and checking it out. This entailed putting a new processor board on the helicopter and installing  a new GPS as I’d stolen the originals for the silver ball. I just returned from flying it about 20 times. Its currently set up to takeoff, hover for 15 seconds at 2m then land.  Here is a picture I took tonight of it sitting in the back of the truck after the flights.



We also are now using a new tool that was first tested with last weeks blue ball flight. The FAR desert is really hard on things like laptops. So when we setup the vehicle and then cycle valves, read voltages, check out the GPS and telemetry links we had been brining a laptop out to the vehicle. The Laptops are hard to read in the Sun and the sand gets every where. So I built a little box that had a daylight readable 4x20 reflective LCD two twist and push knobs and allows us to do all the checkout. Its about 1/3 the size of a normal laptop  and has enough battery in it to run for 48 hours. Its in a solid aluminum case and is pretty rugged. It also worked tonight with the helicopter, we did all the heli flights without setting up the main telemetry station and the computer.

Here is a picture: (Its about 8” long)



I also upgraded the laptop when the spare laptop died.  Ebay is your friend, I picked up a semi rugged Dell for 25% of what a new rugged dell would cost:


All the damage on the Silver ball from the eventful truck ride has been repaired and it should be back together for more static firing next weekend hers a picture of the motor and the ball.


This coming weekend we are going to have a busy weekend, we hope to:

  • Tether hover the blue ball.

  • Static test the silver ball.

  • Fly the full LLC profile from the pads with the Helicopter.

  • Do the first steps of the peroxide processing with the 1 55 gal drum of 50% food grade we got months ago.

This will probably take two full days. I’ll keep you all posted.

Saturday, June 06, 2009

Business ethics and cuts by a thousand lawyers.

A long time ago a normal mortal  could buy rocket grade peroxide. Then someone crashed their rocket pack and sued the  peroxide supplier.They won and the supplier lost more on that suit than they had erver made on the small rocket grade perxode sales. So they did the smart thing and stopped selling rocket grade peroxide to anyone that did not have a government contract.

Three or four months ago I was very worried about peroxide availibility as peroxide propulsion was not running and xlspace systems had stopped producing. So I set about to refine my own. Stabilized 50% hydrogen peroxide is a widely used industrial chemical, and seemed to be generally availible.  I consulted with an expert that had been in the usiness of refining rocket grade perixude and decided to follow his reccomended process.

I got a sample 55 gal drum of 50% food grade from the local chemical supplier and built the plant to do the process. If you can get 70% semiconductor grade you cut out two steps from the process.  There are only two chemical suppliers doing bulk proixde distribution in the U.S. One got burned as described above and will not sell to anyone that is doing “rocketry”. the other suppleir does not produce rocket grade peroxide, they do produce 70% semi. so we started the process of having them review our facility and procedures so they would sell us 70%, rather than the commonly availible 50%. After a number of weeks and many exchanges we got the following response:

First thank you for your time and patience as XXXXX reviewed your request to purchase hydrogen peroxide.  As outlined in your information, your process would concentrate the material to 85-90% for use in rocketry.  You forecast an ongoing use of ~ 10K lbs per year of 70% product.

Our review involved the technical aspects of your work, product stewardship, regulatory affairs, and a legal & liability review.Everyone was impressed with your facility and apparent knowledge of hydrogen peroxide handling.

We have made the decision not to supply Unreasonable Rocket directly or through distribution.  Our decision was really made based on our perceived risk of exposure for a very small volume of business.   We will also communicate this to XXXXXX(the distributor we were buying 50% food grade from.)

We wish you well in your future endeavors and look forward to reading about your successes.

So if I had hidden what I do, or been dishonest about where the peroxide was going I could have continued to buy the 50% food grade. Now niether peroxide supplier will knowling sell even the 50% food grade if it is going to Unreasonable Rocket.  I know of others using peroxide for rockets that have set up shell companies “bozos chemical safety systems” or the like, buy peroxide under an assumed use and then refine for their rocket belts, drag cars or whatever. Others have “friend companies” buy it for them etc.. My personal business ethics don’t feel comfortable with that. As a result of being honest and upfront about what I’m doing the  door is closed.

No discussion of what insurance do you carry, what sort of liability release will you sign etc… Just no. People should be allowed to take risks. My familiy knows that if something happend to me it was my choice. They also know how strongly I feel that lawsuit lottery is destroying the fabric of what made the USA  great. Americans were once risk takers.  

What we are doing is far enough outside the normal industrial processes that any one doing business with us is not following their carefully coregraphed ISO9000 script. As a result the system is not perfect. That is why when I get a valve that supposed to have compatible materials in it I TEST IT. If I asked for viton and they sent buna-n then they screwed up, in the normal  events that sort of screw up would cause a leak. With 90% peroxide it could cause an explosion.  This is my responsiility, a larger  organization would have a detailed incomming inspection for anything that critical, I don’t so its my responsibility.  Its why we test things at FAR were we have a bunker to hide in. Its whey we presurize and fly the vehicle remotely, its why we make people at FAR seek shelter in the viewing bunker when we are trying something untested.  What we do is risky, but we try not to take stupid risks.  When I started going to FAR I looked around  and saw a bunch of 40+ year old guys that normally drive a desk out in the hot desert sun doing hard physical lablor. One of my very first donations to the place was an AED automatic defibulator and a breathing  oxygen bottle. At the time it was the largest check I had yet written for my new rocketry hobby. 

If I screw up amd blow my self up, it was my choice to take the risk, its not the fault of whatever other things happened in the chain of cauasality, I knowlingly put myself in that position.

Damm the lawyers.

BTW we flew the blue ball tethered in high winds today and got mixed results, no damage, but control problems in the winds. more later.