Sunday, May 31, 2015

Quick tank update...

The goal for the composite tanks are 250PSI operating 500 psi design burst and 375psi qualification.
Today the tank I tested failed at 375psi.  When I blew one end out, I did not re-bond the opposite end, the opposie end then failed. (Sort of expected)  When it failed it also split lengthwise.

John is gong to make me some new tubes to test.. with a peel ply layer at the bonding ends and an additional layer on the ends for additional strength on the end caps.
We may add enough material to have bolted ends as that allows you to disassemble and inspect etc...

I also need to slightly rework my seals as the tank seeped until the pressure came up and the seals seated hard. (IE it seeped at 50psi, but stopped at 125 or so)

The current conceptual launcher uses bundles of 4" tanks so the next tube samples will be 4" The current sample is 3"

Thursday, May 28, 2015

hardware again...

My  current concept for a flight weight tank is a carbon tube with a poly liner inside.
I machined some end caps and John Newman gave me a flight weight carbon tube.
The first test failed because the retainer plug on the end had the glue fail, so I sanded the area better and I'm waiting for the glue to dry to try again.

Thats hardware project #1.   hardware project #2 was my idea, but the majority of the work was done by Monroe King.  its the spectra operated valve concept I posted about a week or two ago.  Monroe machined a beautiful valve and I then proceeded to make it ugly. First I just used a 1/4 20 bolt with a slot cut in the head and  filed smooth for the retaining rod.   Second I needed 8 fittings to get from the 1" diameter valve body to the right fitting for my hydro tester. I also did not have any nicrome wire so I used some 0.032 stainless safety wire instead. Attached is a you tube video of the successful valve test...

Wednesday, May 27, 2015

What follows below is a "mind map" I put together 2 weeks ago to think about how to get to orbit.
Not every leaf of every branch needs to be evaluated. On some branches I only need one leaf to work the other can be abandoned.
The currently Active leaf's are Red

Decision Tree
Tank Technology:
Welded Aluminum
Irrigation Tube
HP 6061
Rolled Sheet
Electroformed Sphere
Wellmate Stock (Acquired samples)
Wellmate Re-wound
PET Stock/Reblown (acquired large PET bottles)
Pet Reblown inside Shell
RotoMolded in shell
Poly Bag Liner Test hardware has been fabricated

3D printed Regen
Aluminm A motor design was quickly done and sent out for quote. 3D printed price was acceptable. More than 3:1 variance in differnt vendors.
Fabricated Regen
Plated close
Saddle Jacket
Poly Heat Shring
Poly Cast
AL Tube?
HP Solid for Last stage Asked one of my solid friends to look at this.
GPS Selection
Piksi If we have a GPS it will likely be this.
Fiber  (ordered surplus fiber gyro from ebay wil use to evaluate different mems sensors.)

Presurization System
Blowdown with one intermediate valve
Liquid nitrous
       Presurized bottle and regulator.(If our composite tank ideas work as well as they seem to then this is not really a win as the blowdown tank tech from a mass standpoint is almost as good as hightech carbon wound presurant bottle.

PayLoad  (Cubesats have used CC1100 based radios to communicate so its a reasonable choice)
CC1100 based Custom
BigRedBee I have one of their 70cm tranmitters in hand, payload < 50gms possible.

Architecture trades
Custom C++
Trajectory Design
Custom C++
JSBSim (I think I've secured some help here that is very familiar with JSBSim) 
Control Laws higher fidelity sim
Hardware in Loop Testing
Mission Design
Wild Ideas
  Jet Lifter
Propellant Selection
Pressurant Burining?
Launch Location (Within in a month when the archetectures starts to shake out its time to go to FAA and start discussing this)
On a Boat?
On a Plane?
Traditional Range?
NM Space Port?
Space Fl?
Intermediate Testing
Limits to what can be tested at FAR?

Monday, May 18, 2015

Rocket Motors...

In an ideal world I'd just have the rocket motors 3D printed.
I believe (I've sent out a sample file to be quoted) that they will be prohibitively expensive.

If I could figure out how to make shapeways 3D printed metal parts work that might be affordable.
(Long time followers will recall that the shapeways process does not work for internal cooling passages, so the inner and outer need to be assembled from separate parts, and if you then weld them together they get porous as the high welding temperature drives out the brass used to infuse the stainless powder.)

So one of the tests that I might do is to see if I could  make a 3D printed rocket design that Shapways could make, then I would solder or low temp braze the outer shell over the motor.
Another possibility might be to plate the resultant leaky welded motor ... a number of things to try...

One could always build saddle jacket motors.

Friday, May 15, 2015

Another way....

Low cost access to space.....
Many believe that reusable vehicles will ultimately give us  low cost access to space. The Shuttle was supposed to do this.  Spacex is rapidly approaching this goal with the first stage. I  assume that once the 1st stage is recovered they will soon try to recover 2nd stages, capsules, solar panels, trunks, payload fairings, all the way down to minutiae like GSE cables and dust covers. The eventual goal being airline like reuse. This will eventually lead to a beautifully refined optimized jewel like perfectly executed complex space launch system.  Every component will be reusable, repairable, refurbishable .

Right now if a vacuum Merlin has a bad day you loose the whole mission. In the airline industry engine failures are a regular occurrence, but since they have robust intact abort capability and procedures we don't hear about it. If a rocket is going to achieve airline like  operations it will need this capability as well.   Once the value of the reusable vehicle is as great or  greater than the payload intact abort gets even more compelling.

Some large helicopter systems may require 60 hrs of maintenance for  every flight hour.
How much maintenance will a reusable space craft require?

Amortizing the cost of developing the reusable space craft will need to be recovered, fixed and variable operations costs, rebuild and overhaul costs etc.... etc... etc... all of this will need to be covered.  Suppose spacex does 100 flights a year and the rocket is 100% reusable and propellant is free....  They currently have ~4000  employees this means with all other costs at zero the standing army at 100 launches a year will cost $4M a launch if everything else was free.

Even with this best case scenario this is a long path and with chemical propulsion the gravity well is deep.

I can buy any number of Rolex watches (lowest cost on on the page is $31K) .  I expect it to be a fine example of swiss craftsmanship. If it ever breaks or misbehaves it will be delicately repaired by a skilled artisan.  It will be a family heirloom for generations to come. If I go on amazon I can find digital watches starting at $3. By my estimation the $3 digital watch probably keeps time as well as the very best all mechanical Rolex. (For an apples to apples comparison the lowest cost mechanical watch I could find is $20.00)
No one is going to repair a $3 watch, you just throw it out and get another. Even if you think throwing it out is wasteful, is it really more wasteful than the standing army of rolex dealers and repair centers that stand behind the use forever rolex?

With the early microcomputer , all of the chips, and boards were replaceable. If a ram chip died it would be individually replaced.  Now the fabrication is so cheap dead motherboards go to scrap. No one seriously considers repairing them.  (Amazon lists 28,000 motherboards under $25.00)

What if space craft were so cheap that if one failed it wasn't a big deal? You just launched another one...My guess is that if there is a production failure on the $3 digitial watch they do no rework.
For some kinds of cargo this is not acceptable (Humans for instance)

My friend Joe Caroll has a saying to reduce the cost of space we need reusable rockets, or reusable rocket factories.  Without reuse things just get simpler. At some point if you can build them cheap enough in an automated way, expendable is cheaper than reusable.(How may of you gray hairs remember TV repair shops?)

A rocket is a complex item with first, second,  third stages, different engines,tanks, fittings etc...Each one optimized, a reusable rocket factory will need a flight rate high enough to justify this factory. If your only building 10 a year does it make sense to build a fully automated factory? How about 640?  You will use a lot more automation building 640 than you will building 10.

This brings me to my favorite rocket that almost was, OTRAG See here, here and here. Each 1 Ton rocket had 64 identical Common Rocket Propulsion Units  (CRPU) . Each otrag CRPU had one moving element a single ganged on-off throttle valve.

One of the concepts I've personally explored for a small launcher is an  otrag launcher sized to launch a 3U cube sat.    Instead of having to design 3 stages with 3 different  tanks, valves, motors,  fill ports, testing procedures and handling and transport I only need to design one. I can spend three times as much in optimizing each  element and still be ahead. To be fair they are not identical, you would probably have to hack saw off the nozzle on the "First" stage, and the pressure to do additional lightening on the upper stage would be extreme Some ways this could shake out, a common blowmold liner for tanks with upper stages wound with carbon and lower stages wound with glass....

Also the increased drag and many of the square/cube scaling issues that are bad for Otrag are much worse for a nano-otrag.

Monday, May 11, 2015

Concept for a light weight clean electrically actuated valve.

Pyro valves have(an article written my Tom Mueller on amateur pyro valves) a long history in rocketry. The problem is they are not very reusable and for the amateur testing them and maintaining the system cleanliness necessary for a peroxide oxidizer are challenges.

One of the strongest man made fibers is Spectra or Dyema. One problem with spectra is that is very weak at elevated temperatures.   Here is my concept on using this to make an electrically actuated valve:

The golden thread is a Spectra loop with some nicrome wire wound in it.  Hit the nicrome with a electrical current it gets hot and the spectra fails.

Here is a split view of the closed valve:

When the spectra fails the purple plunger is released and the blue piston moves down the fitting. The purple plunger guides the piston to keep is from cocking while it moves down. When it hits bottom the purple piston falls away.  Here is a split view of the open valve. 

Not sure if this will work, but some time in the next few weeks I will fabricate a test article.

Friday, May 08, 2015

Waking up from a long slumber.

A Story in many parts...

I've been searching for a good rocketry project. The one I really want to do is start up a nano sat launcher business.  Every person I presented my business plan to had the same response, no way you can build a successful  orbital launcher for lest than $XX million dollars. Everyone's XX was different but they were all  at least two digits.

I was not planning to go to SpaceAccess this year.  I had nothing to present and I felt I know what most of the people presenting were going to present and felt the whole thing would be somewhat depressing watching power point after power point saying we are going to fly real hardware "real soon" With the exception of the few groups building real hardware (all of which I have personal friends on the inside) One sees same slides every year with different logos on it, and dam little real hardware.   My wife was visiting her sister in Canada and I woke up Friday morning feeling like maybe I should go to SA15 after all.   The hotel still had rooms for Firday night so after work I borrowed by friend Jeff's Mooney and flew myself to Space Access. (all of my airplanes were rented ).  A lot of people were really happy to see me. After 5 years it still amazes me the impact that my little garage project called "unreasonable rocket" has had on people.  One of the people I was looking forward to seeing at Space Access was Charles Pooley... he did not attend, more on that later.
I did not watch many space access presentations, I spent far more time sitting outside talking to people. One subject of discussion was what I call amateur sputnik, ie what would it take for an "amateur" group to orbit the equivalent of sputnik, ie  the smallest radio transmitter that can be easily detected on the ground.

After returning to San Diego several of us were worried about why Charles had not come to Space Access and why he did not answer his phone. On Monday we learned that he had died in his apartment.  Charles was in his mid seventies and had spent countless hours helping my son and I on the unreasonable rocket project.   He had a vision for small launchers that he and Ed Labouthiller turned into a book (MicroLaunchers). While I disagree with some of his technical designs  (I felt they were too complicated) and disagreed with reluctance to use computers, I did agree with most of the big concepts in Charles microlauncher concept.

I'm I'll be 53 this year, not young, not old, sort of in that neither region were I can see both camps and hints of inevitable entropy introduce themselves to you most mornings.  In the past past three years I've lost my Dad, My Step Mom and my Step Grandmother.  Seeing Charles dream extinguished without a real shot at doing it was just another sign pointing at the impermanence of life.

Building an orbital vehicle is om my bucket list, so all of this adds up to the inevitable question if   not now when. So I guess its now.  In the last week I've started several balls rolling, I have 4 or 5 concepts for composite flight weight tanks.

  1. Our previous flight weight tanks had liner leakage problems dues to bad resin, the trial batch of resin worked the 55gal special order did not. . One of my new  concepts is to build unlined tanks, then take them to a roto-molder and have the insides coated with polyethylene. 
  2. We tried to re-blow a large PET bottle and then cover it in carbon. The fact that we did this as two seperate steps made the resulting tank too heavy as there were fillers and excess to match the carbon support to the liner.  So the current concept is to make a flight weight high temperature composite cover for the PET bottle and then blow the bottel into the flight weight shell in a single step.
  3. I've had the concept of a long composite tubes lined with polyethelene heat sealing bag and high quality machined aluminum end caps.
  4. For a vacuum stage the pet bottle is almost good enough all by itself. So one concept is to just provide a tiny bit of carbon enforcement to the stock pet bottle around its girth and use that as a 100 psi tank.
I've restarted my tank project so that in the next few months I should have at least one of each of these concepts to test.

Additionally if these don't work I have two more concepts to try:

  1. Take a aluminum an tank form. Have it powder coated with thick clear powder coat.Wind a carbon shell over that. Use Lye do dissolve out the inner aluminum shell leaving a carbon shell with thin uniform poly liner.
  2. Wellmate makes really light poly lined fiberglass water tanks for residential use. I used one of their tanks as the fuel tank on silver.  They are almost flight weight as a stock COTS item.  One coudl do much development work with the stock tanks and for the final flight weight version one could aquire the un wrapped liners and wind carbon instead of eglass over them and.

In addition to restarting the airframe tank work I've started the ball rolling to get some fresh propellant delivered to FAR.

In the very short term I need to get my Garage cleaned up, I'm just going to pack and remove anything not rocket related and put it in storage.

Over the next month I will formulate a plan, a rough schedule and list of tasks.  Many people have offered to help, some have almost begged me to organize an effort they can participate in. 
I'm not good at delegation I like to get in there and do it myself, if this is going to work I will need to work on that. At the same time having the project turn into a free for all doesn't work either.

Some things I know I will need help with:

  • I need the smallest transmitter that can be detected on the ground and last for at least a week with batteries, it can have solar panels if they are lighter.
  • The current notional concept has a guided 2nd (or 2rd) stage that points, spins up and ignites an unguided solid final stage that puts the  transmitter in orbit. I think I need someone that can build a final stage high mass fraction solid to be the final stage, I think I have someone for this, but if this is your area of expertise I'm open for talks.
  • I need someone to help me put together a good simulation  ie to simulate the rocket getting to orbit. And hopefully to eventually do hardware in the loop simulation...
  • I'll need help on GNC, I can do GNC hardware and understand the concepts, but my GNC stuff was not great.
  • I need someone local to help video,photograph and blog things.
  • I will need help at FAR (two people) twice a month starting in September for at least a year.
  • I need someone that likes data, I gathered lots of test data in my last effort, I just never found the time to take this gathered data and put into presentable form, ie I'll provide a file of raw sensor data... it would be nice if this could be calibrated, trimmed to show the interesting parts and put in nice graphical form....
  • I need someone that likes to fabricate things.... to help with some of the development. For example I have some concepts for really light robust actuated valves, I could spend three weekends fabricating several sets, or I could spend an hour or two describing the concept to someone and let them fabricate and test. 
  • If someone wants to own the FAA part of this project I'm not sure its possible to deligate this, but I'm open to suggestions...
  • I'm open for someone that might want to help raise social media funds, ie kickstarter, indigogo, subscription access to the progress blog two weeks early etc... so anyone with ideas or a desire to do this would be helpful.
If you see anything on this list you want to help with, or other ideas you think you can help with 
I'm more than willing to entertain the idea.  At this point this is an amateur not for profit project to get something tiny in orbit. When that succeeds I will want to turn it into a proper business, how to give the volunteers involved with this project a share and value in the follow on potential company is something to be worked out upfront and I'm open to ideas.

In the next few weeks I'll do follow on posts with an outline of the notional vehicle,  and a number of the detail concepts that I am in the process of fleshing out.