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.
Monday, November 23, 2009
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 ?
(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.
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.
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....
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.
Blue:
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.
Silver:
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.
Blue:
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.
Silver:
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.
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