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Armadillo Flies... Briefly
david.given writes "Armadillo Aerospace did their first untethered test flight last week, at the Oklahoma Spaceport, using their new tube-shaped rocket. Predicted height was fifteen hundred feet; unfortunately a computer failure caused the vehicle to tip over and dive into the ground from a hundred feet up, causing severe damage (i.e., it requires a rebuild, not a repair). See the report and the slightly depressing video footage."
Nuts
These guys are nuts
Slashdotted too. (Tastes like chicken)
unfortunately a computer failure caused the vehicle to tip over
What operating system were they running?
FoundNews.com - get paid to blog.,
computer malfunctions seem pretty common for these guys ;-)
unofficial reports also state that their webserver was being sent on the rocket as a guinea pig.
"It can only be attributable to human error. This sort of thing has gone on before, and it has always been viewed as human error."
Palaces, barricades, threats, meet promises
Think of it: id Software can be the first game company to be qualified advertise games with "Real Life Space Physics" if John Carmack comes back alive from one of his space flights.
Coming Soon: Doom VIII: Space Warfare
------
Amadaeus
The last bastion of Mathie-ism
Click here for the Google cache of the home page. Not much info, since the cache was made before the test flight.
Tuus crepidae innexilis sunt.
for some inexplicable reason, i'm suddenly in the mood for a game of lawn darts...
don't try to compile my kernel while flying a rocket.
The World's Worst Webcomic!
Does anyone see the humor in a bunch of rocketgeeks, led by a famous computer programmer having their maiden untethered test flight ruined by a computer failure?
Not a physics or engineering problem, but a computer problem.
Heh. Goes to show that computing really is rocket science. In fact, it's harder!
This is what happens when you name your vehicle after one of the dumbest animals alive...it acts like one.
...because if that had happened anywhere near my house, it would've been *much* uglier.
dan, n.j. resident since 1975
;)
cant even get onto the site...super /.ed
Information Technology White Papers and Research
Someone please G2 Shareaza the video before it gets totally slashdotted.
Seastead this.
Look like Jon should look at the Bot AI so it stops cratering.
Player 0
Bot -1
My ignorance is a perfect shield against your logic.
fucking insestive clod!!!! now all the spam harvesters will get those email addresses!!!!! that was nasty suicide!!!
M.C. Hawking? I thought you were dead...
Wow, /.ed after about a minute...kinda reminds me of the video footage actually...
(since it already seems to be slashdotted from here)
Perhaps Mr. Carmack should stick to shooting monsters in outer space instead of going there.
Sigpilot : I'm in the pipe, 5 by 5.
From reading post, it sounded like it went up 100 feet, tipped over, and smashed into the ground. The video shows a different story. That thing was going over right from liftoff. That's some pretty serious instability.
It's mod down time.
Ahem.. Aren't all rockets tube shaped?
Microsoft issues a statement calling the launch a "complete success" and promises 150 feet by "service pack 2"
Resistance is futile. Reactance buggers it up.
So a computer malfunction caused the rocket to tip over? To bad they didn't have a robot helper to fix the malfunction and send the rocket into space like in the 80's movie classic "Space Camp"
Flight Unsuccessful
f li ghtUnsuccessful.mpg
b un ker.mpg
November 12, 13, 15, and 16 (busy week!) meeting notes
Flight Unsuccessful
We prepared for and conducted our first remote flight test at the Oklahoma Spaceport facility in Burns Flat this week. Several lessons were learned.
We built a checklist for our flight operations, which was a very good idea. Going through it before setting off caught several things we almost forgot.
The five hour drive from Dallas to Burns Flat was rougher on the equipment than expected. The tarp we put over everything to keep people from staring was damaged by the wind in several places, and the wooden cradle we transport the vehicle on actually broke one of its 2x4 support bars. We are probably going to arrange some hoops for the trailer so we can tarp it like a covered wagon in the future. I may consider an enclosed trailer with a suspension in the future.
Everyone was extremely helpful in Oklahoma, and we set up in the middle of a service road well off from the main airport runway. Our expected altitude with only five gallons of peroxide was under 1500', and our parachute drift range with 13 mph winds was only about 2000', so we had plenty of room. Bill Kourie from OSIDA stayed with us to communicate with the air traffic control tower during our launch activities.
Our setup was a bit slower than we expected, but everything got done fairly smoothly. The VOX on the radios we brought was more trouble than it was worth, often triggering with wind noise, but this was our first time using radio communication.
We did a full water test, then loaded up five gallons of peroxide. The engines all warmed quickly, and ran perfectly clear, even though it was in the mid 50s.
When we were cleared for our launch, I smoothly throttled up the engine over a two second period. The vehicle tilted a little bit on liftoff, but seemed to straighten out, but it then continued tipping, eventually tipping all the way over and flipping into the ground from a hundred or so feet up.
There was still peroxide left in the vehicle tank, but all the pressure had drained out by the time we reached it. We tipped it up to allow the remaining peroxide to drain down into the main engine and slowly catalyze away, then we carried the vehicle back to the road to run some low pressure water through it to clean it up.
http://media.armadilloaerospace.com/2002_11_16/
We drove the remains to our bunker to strip off the good parts, and left the main body there.
http://media.armadilloaerospace.com/2002_11_16/
Analysis
The telemetry cut off only four seconds after throttle-up, indicating that the computer died, but there was very valuable data.
Immediately after liftoff, there was a +Z angle rate kick, probably caused by the funny takeoff aerodynamics underneath the tail flare. The piece of aluminum sheet metal we put under the rocket for ground protection was folded in half and crumpled up after liftoff, which was completely unexpected. You can briefly see that in one of the liftoff video frames. The rate peaked at 22 deg/s, with the opposite attitude engine full on, then it started coming back down. The liftoff test last week did not show this behavior, but the feet were changed, and the surface was different this time. It is also possible that the main engine mount was slightly distorted by the travel.
The Crossbow stopped updating 1.25 seconds before telemetry ceased.
The vertical acceleration was right at one G when the Crossbow stopped updating, and very smooth. This was slightly higher than expected, indicating about 600 pounds of thrust from the engine at 280 psi takeoff tank pressure. The plumbing on the test stand was definitely limiting performance compared to the straight shot on the vehicle. The welded catalyst pack continues to perform very well.
The battery voltage started dropping rapidly at this point, but the computer continued operating for another 1.25 seconds, until the battery voltage reached 9v, at which point telemetry ceased. The 15v power converter for the Crossbow probably suffered a voltage drop before the 5v power converter for the main computer. The main engine feedback potentiometer reading fell off as the 5v supply dropped below 5v, and the engine pressure transducer started falling off faster than it should as the supply voltage dropped below 10v. All of this points to a general power system failure, rather than just a computer power failure (which has triple redundant connections to the main power supply from the manned lander work).
During the last 1.25 seconds of operation, the computer continued using the last valid Crossbow data, which caused it to hold the same two attitude engines on, which built up momentum on all three axis. Presumably the attitude solenoids all closed when the computer died and stopped sending an active signal to the solid state relay boards, but quite a bit of momentum could be built up in that time. The main engine would remain in the full-open position. As the vehicle did its flip, you could see it slowing down while it was pointed upwards.
The flight control code has in the past had stop-all-engines behavior when the crossbow stops updating, but on this flight there was no cutoff checks, which was a mistake. If there had been, the rocket would have just dropped from about 20' in the air, and suffered much less damage. The exact timing for deciding the crossbow isn't working is a tough judgment call, but a quarter second should certainly be enough time to decide that the attitude engines should cut off. The decision to cut the main engine is harder, because the vehicle should be able to continue flying as an unguided, aerodynamically stabilized vehicle if it is going fast enough, but right-off-the-pad, it could turn into a land shark.
There was one GPS update after liftoff, showing it at three meters above the ground, but with only a small vertical velocity. The processing latency on GPS velocity and position may be different.
My initial thought was that something had shorted, perhaps in the motor drive feedback or pressure transducer, which have power running to them from the main bus. When we opened the electronics box, the cable to the battery positive terminal was not connected. The battery still had full voltage in it, so we believe that the terminal came off during the flight, causing the voltage drop that led to the failure, rather than during the crash. It is unfortunate that it seemed to work during the water test and warm-ups, but the drive from Texas probably loosened the connection to the point that it was barely hanging on. The batteries have slip-on connectors, which have bothered me for quite a while, but screw terminal batteries are not available until much larger sizes. We are going to drill our own screw terminals in the lugs of future batteries, and possibly solder them as well.
The Damage
The important thing is that the Crossbow IMU survived, because that costs more than everything else put together, and can have an 8 week lead time. I am going to buy a backup, in case we aren't so lucky next time. Crossbow is now offering (but not shipping yet) an improved fiber optic gyro IMU with half the drift rate, but they jacked up the price a few thousand dollars.
The main tank actually seems to be ok, but we are not going to trust pressurizing it again.
The fiberglass nose and tail cones were both broken.
The engines casings for the parachute tower still look OK, I guess they bent away before the body hit them.
The tower was mangled, of course.
The pressure transducer at the top of the tank was broken.
Our aluminum engine frame at the base was bent a fair amount.
One attitude engine broke the jet holder fitting off inside, but we can probably remove it.
The main engine servo valve had the half inch pipe fitting permanently bent in it, but we were able to swap that section of the valve with scrap from a valve broken in a different way, so it seems to have been saved, but we haven't leak checked it yet. The plastic connectors on the valve were very brittle from the cooking they took on our hover tests that stuck to the ground, and broke when disassembled. We are going to run Tefzel wire all the way to the valve motors in the future, instead of using the supplied pigtail connectors.
All the plumbing survived, except for the two fittings that jammed in engines.
All the engines look ok, but we will have to carefully check that the main engine hasn't bent its inlet connector.
The WinSystems SBC computer seems dead. The memory SIMM was ripped out of the socket, which also partially detached, and even after reseating everything, it won't boot. The flash drive still works fine in another system, which saves me the effort of building a new linux system from my last backup.
The antenna connector on the Esteem wireless unit is broken, but the unit looks OK. Taking the case apart showed that we can save a large amount of electronics area and several pounds by just mounting the guts and ditching the case.
Both batteries have cracked cases, although neither one spilled any acid gel in the box.
The fan over the power supplies was wrecked.
The A/D breakout board was smashed by the batteries.
New Vehicle Work
We are going to proceed with the next vehicle design, as if this test had succeeded, rather than rebuilding an identical vehicle. The major change is to move to four large engines that are differentially throttled, instead of the single large engine and four solenoid controlled attitude engines. This goes back to the control style of our very first lander, and is motivated by the fact that we are bumping up against vehicle size limits for being controlled by the thrust we can get from solenoid based attitude engines.
The vehicle will pay much more attention to streamlining, with the intention of being capable of supersonic flight. The nose will be 10 or 15 degrees, and we will be using a honeycomb composite constructed box fin arrangement for stability instead of the tail flare. There will be no external protrusions or loose cables along the sides. We are going to try a rear parachute ejection system, with an intentionally crushable top nose section
The propulsion system will have a master cutoff valve, run by a separate watchdog computer. We have talked about this for ages, but not yet implemented it. If implemented on the last vehicle, it would have dropped it from a much lower altitude.
We are going to make many changes in the electronics to improve reliability.
There will be a backup 9600 baud telemetry radio, in addition to the Esteem 802.11b.
No more solid core wire for DB connectors, move to 22 ga stranded Tefzel wire. All 18 gauge wire is already Tefzel, but I had been using solid wire for soldering serial cables, which is a known poor practice. I am moving to mil-spec double-crimp terminals for all flight hardware, instead of the single-crimp industrial terminals we have been using.
Mount all the electronics, except for the inertial unit, on a vibration isolated board.
New A/D breakout board
The breakout board that WinSystems sells for their A/D board takes up a lot more space than necessary, and uses bare wire screw terminals for input, so we are going to replace it with a custom board that is smaller and takes ring terminals.
16 signal inputs with #6 ring terminals, one ground is common to all signals measured.
The range is +/- 10V, so we need to cut the main battery voltage in half before sampling. It is a toss up if this should be done on the A/D breakout board, or on the power supply board. There should be a grid of holes for soldering in random resistors or capacitors to modify signals.
The grounds are common to all the signals, so I think all we need is a single ground ring terminal that we will run back to the power supply.
The connector going to the A/D board is a 26 pin ribbon cable with the following pinout:
1: ch0 2: ch8
3: ch1 4: ch9
5: gnd 6: gnd
7: ch2 8: ch10
9: gnd 10: gnd
11: ch3 12: ch11
13: gnd 14: gnd
15: ch4 16: ch12
17: gnd 18: gnd
19: ch5 20: ch13
21: gnd 22: gnd
23: ch6 24: ch14
25: ch7 26: ch15
Watchdog Board
Trivial microcontroller that watches a continuous signal from the main computer, and uses a private motor drive to open the master cutoff valve only when the main computer is healthy.
Input:
One optically isolated digital line from the main computer
Private +12v / GND
Output:
Two #6 ring terminals to control the master cutoff servo valve (the main computer will still read the pot feedback of that valve)
Power supply board
Multiple, diode isolated batteries for redundancy, with an additional port for running on external power
External charging ports for each battery, so the electronics don't need to be taken out of the vehicle for charging.
Short run from batteries to boards, no in-line power switch. Use the power pin on the DC/DC power converters for switch-on. Use redundant switches to prevent a switch glitch under vibration from turning everything off.
Run nothing from the unregulated power supply, except for the A/D line for current voltage level. We previously ran a couple things from the unregulated 12v supply, like the Esteem wireless unit, and the pressure transducer. It is possible we were losing telemetry momentarily earlier than the computer died, depending on the details of their power use.
Instead of running wires from the power supply board to jumpered barrier strips for distribution as we previously did, build plenty of terminals directly onto the power supply board. At a minimum:
Lots of grounds.
Unregulated +12v: Battery A/D line
+5v: computer (two lines)
+5v: 6 motor drive potentiometer feedbacks
+5v: several spares
+6v: laser altimeter
+12v: pressure transducer
+12v: GPS
+12v: Panel-PC LCD display
+12v: Several spares
-12v: Panel-PC LCD display
+15v: Crossbow IMU
We might want to use a higher voltage for the IMU, as the range is 15v-30v, and we have been warned by someone about running avionics at their minimum recommended voltages. Today's result seem to corroborate that it is closer to going out than the rest of the systems.
Current draw signal for telemetry? If we ever have a short somewhere, this would be helpful in diagnostics.
Isolated voltage signals for each battery? If we don't have that, telling when a battery has failed will be difficult.
Actuator Boards
Our current solid state relay board still has bare wire terminals (although they are high quality ones that haven't yet given problems), it still has the old power supply on it that we don't use, and one bit on the input connector is flaky, so it needs to be replaced.
Isolated voltage signal for A/D telemetry?
Isolated continuity checks for each actuator? The motor valves can be self-tested by watching the potentiometer feedback, but solenoids and pyro would need a low-current test signal. The actuator battery needs to be completely isolated from the main battery to avoid noise problems, so a continuity sensor would need to be isolated as well.
We have known needs for up to six solid state relays and six motor drives, so building for eight and eight is probably good planning.
Wonderfull. Great. I really don't care. Can y'all get back to working on Doom III now? Thanks.
Sig:
Barbeque is a noun. Not a verb.
Quake physics is nothing like real life physics. ;)
Too many users... blah blah blah
Probable cause: http://www.slashdot.org
Try again in a few seconds...
-xian@idsoftware.com
-- "Government is the great fiction through which everybody endeavors to live at the expense of everybody else."
Probable cause: http://www.slashdot.org
Try again in a few seconds...
-xian@idsoftware.com
Boy, that "from the lawn-dart dept." crack is painfully accurate. I just got the video (at ~12K/s), and that thing came almost straight down! (Yes, there was much tumbling involved, but at impact it was pointed pretty much 180 from the way it started.)
Also, if you look close, you'll see metal (?) plates flapping on the ground at launch. (Looks like a folding launch pad.) Did they interfere with the rocket and throw its' stabilization routines off? Who knows.
"...America's great minds of today, teaching America's great minds of tomorrow. Poor bastards." -- A Beautiful Min
+1 Technical
-1 Artistic
-1 Content
-1 Antisemitic
Score: -2 Lame
Predicted load of fifteen hundred users; unfortunately a web server failure caused the web site to tip over and dive into the ether from a hundred user load, causing severe damage (i.e., it requires a new server, not a new OS)
First Falcon-1 to orbit, then Falcon-9. Then I can die a happy man.
If my computer wasn't working, I couldn't get it up either. ;)
Replace PocketPC with working tape recorded.
You can't judge a book by the way it wears its hair.
linking directly to an mpeg from slashdot is pretty irresponsable.
I believe that you stated in your write-up that you are going to go on the assumption that this one test had been successful, and move to the next model which will be capable of supersonic flight. After that, the X-prize level vehicle.
It feels a bit like you are more actively trying to get to the X-prize level sooner rather than later; earlier entries seemed a bit more relaxed about timings.
How much pressure are you feeling as far as competing with the other teams? How far ahead or behind to do you perceive yourself compared to the other teams? How do you like your chances of winning it all?
(last silly question): Do you feel those competitive "deathmatch instincts" kicking in to win against the other teams?
Sometimes it's best to just let stupid people be stupid.
The filename is: Armadillo_Aerospace-flightUnsuccessful.mpeg
Hollow words will burn and hollow men will burn.
Armadillo Aerospace News Archive
n ker.mpg
Analysis
Flight Unsuccessful
November 12, 13, 15, and 16 (busy week!) meeting notes
We prepared for and conducted our first remote flight test at the Oklahoma Spaceport facility in Burns Flat this week. Several lessons were learned.
We built a checklist for our flight operations, which was a very good idea. Going through it before setting off caught several things we almost forgot.
The five hour drive from Dallas to Burns Flat was rougher on the equipment than expected. The tarp we put over everything to keep people from staring was damaged by the wind in several places, and the wooden cradle we transport the vehicle on actually broke one of its 2x4 support bars. We are probably going to arrange some hoops for the trailer so we can tarp it like a covered wagon in the future. I may consider an enclosed trailer with a suspension in the future.
Everyone was extremely helpful in Oklahoma, and we set up in the middle of a service road well off from the main airport runway. Our expected altitude with only five gallons of peroxide was under 1500', and our parachute drift range with 13 mph winds was only about 2000', so we had plenty of room. Bill Kourie from OSIDA stayed with us to communicate with the air traffic control tower during our launch activities.
Our setup was a bit slower than we expected, but everything got done fairly smoothly. The VOX on the radios we brought was more trouble than it was worth, often triggering with wind noise, but this was our first time using radio communication.
We did a full water test, then loaded up five gallons of peroxide. The engines all warmed quickly, and ran perfectly clear, even though it was in the mid 50s.
When we were cleared for our launch, I smoothly throttled up the engine over a two second period. The vehicle tilted a little bit on liftoff, but seemed to straighten out, but it then continued tipping, eventually tipping all the way over and flipping into the ground from a hundred or so feet up.
There was still peroxide left in the vehicle tank, but all the pressure had drained out by the time we reached it. We tipped it up to allow the remaining peroxide to drain down into the main engine and slowly catalyze away, then we carried the vehicle back to the road to run some low pressure water through it to clean it up.
flight video
We drove the remains to our bunker to strip off the good parts, and left the main body there.
http://media.armadilloaerospace.com/2002_11_16/bu
The telemetry cut off only four seconds after throttle-up, indicating that the computer died, but there was very valuable data.
Immediately after liftoff, there was a +Z angle rate kick, probably caused by the funny takeoff aerodynamics underneath the tail flare. The piece of aluminum sheet metal we put under the rocket for ground protection was folded in half and crumpled up after liftoff, which was completely unexpected. You can briefly see that in one of the liftoff video frames. The rate peaked at 22 deg/s, with the opposite attitude engine full on, then it started coming back down. The liftoff test last week did not show this behavior, but the feet were changed, and the surface was different this time. It is also possible that the main engine mount was slightly distorted by the travel.
The Crossbow stopped updating 1.25 seconds before telemetry ceased.
The vertical acceleration was right at one G when the Crossbow stopped updating, and very smooth. This was slightly higher than expected, indicating about 600 pounds of thrust from the engine at 280 psi takeoff tank pressure. The plumbing on the test stand was definitely limiting performance compared to the straight shot on the vehicle. The welded catalyst pack continues to perform very well.
The battery voltage started dropping rapidly at this point, but the computer continued operating for another 1.25 seconds, until the battery voltage reached 9v, at which point telemetry ceased. The 15v power converter for the Crossbow probably suffered a voltage drop before the 5v power converter for the main computer. The main engine feedback potentiometer reading fell off as the 5v supply dropped below 5v, and the engine pressure transducer started falling off faster than it should as the supply voltage dropped below 10v. All of this points to a general power system failure, rather than just a computer power failure (which has triple redundant connections to the main power supply from the manned lander work).
During the last 1.25 seconds of operation, the computer continued using the last valid Crossbow data, which caused it to hold the same two attitude engines on, which built up momentum on all three axis. Presumably the attitude solenoids all closed when the computer died and stopped sending an active signal to the solid state relay boards, but quite a bit of momentum could be built up in that time. The main engine would remain in the full-open position. As the vehicle did its flip, you could see it slowing down while it was pointed upwards.
The flight control code has in the past had stop-all-engines behavior when the crossbow stops updating, but on this flight there was no cutoff checks, which was a mistake. If there had been, the rocket would have just dropped from about 20' in the air, and suffered much less damage. The exact timing for deciding the crossbow isn't working is a tough judgment call, but a quarter second should certainly be enough time to decide that the attitude engines should cut off. The decision to cut the main engine is harder, because the vehicle should be able to continue flying as an unguided, aerodynamically stabilized vehicle if it is going fast enough, but right-off-the-pad, it could turn into a land shark.
There was one GPS update after liftoff, showing it at three meters above the ground, but with only a small vertical velocity. The processing latency on GPS velocity and position may be different.
My initial thought was that something had shorted, perhaps in the motor drive feedback or pressure transducer, which have power running to them from the main bus. When we opened the electronics box, the cable to the battery positive terminal was not connected. The battery still had full voltage in it, so we believe that the terminal came off during the flight, causing the voltage drop that led to the failure, rather than during the crash. It is unfortunate that it seemed to work during the water test and warm-ups, but the drive from Texas probably loosened the connection to the point that it was barely hanging on. The batteries have slip-on connectors, which have bothered me for quite a while, but screw terminal batteries are not available until much larger sizes. We are going to drill our own screw terminals in the lugs of future batteries, and possibly solder them as well.
The Damage
The important thing is that the Crossbow IMU survived, because that costs more than everything else put together, and can have an 8 week lead time. I am going to buy a backup, in case we aren't so lucky next time. Crossbow is now offering (but not shipping yet) an improved fiber optic gyro IMU with half the drift rate, but they jacked up the price a few thousand dollars.
The main tank actually seems to be ok, but we are not going to trust pressurizing it again.
The fiberglass nose and tail cones were both broken.
The engines casings for the parachute tower still look OK, I guess they bent away before the body hit them.
The tower was mangled, of course.
The pressure transducer at the top of the tank was broken.
Our aluminum engine frame at the base was bent a fair amount.
One attitude engine broke the jet holder fitting off inside, but we can probably remove it.
The main engine servo valve had the half inch pipe fitting permanently bent in it, but we were able to swap that section of the valve with scrap from a valve broken in a different way, so it seems to have been saved, but we haven't leak checked it yet. The plastic connectors on the valve were very brittle from the cooking they took on our hover tests that stuck to the ground, and broke when disassembled. We are going to run Tefzel wire all the way to the valve motors in the future, instead of using the supplied pigtail connectors.
All the plumbing survived, except for the two fittings that jammed in engines.
All the engines look ok, but we will have to carefully check that the main engine hasn't bent its inlet connector.
The WinSystems SBC computer seems dead. The memory SIMM was ripped out of the socket, which also partially detached, and even after reseating everything, it won't boot. The flash drive still works fine in another system, which saves me the effort of building a new linux system from my last backup.
The antenna connector on the Esteem wireless unit is broken, but the unit looks OK. Taking the case apart showed that we can save a large amount of electronics area and several pounds by just mounting the guts and ditching the case.
Both batteries have cracked cases, although neither one spilled any acid gel in the box.
The fan over the power supplies was wrecked.
The A/D breakout board was smashed by the batteries.
New Vehicle Work
We are going to proceed with the next vehicle design, as if this test had succeeded, rather than rebuilding an identical vehicle. The major change is to move to four large engines that are differentially throttled, instead of the single large engine and four solenoid controlled attitude engines. This goes back to the control style of our very first lander, and is motivated by the fact that we are bumping up against vehicle size limits for being controlled by the thrust we can get from solenoid based attitude engines.
The vehicle will pay much more attention to streamlining, with the intention of being capable of supersonic flight. The nose will be 10 or 15 degrees, and we will be using a honeycomb composite constructed box fin arrangement for stability instead of the tail flare. There will be no external protrusions or loose cables along the sides. We are going to try a rear parachute ejection system, with an intentionally crushable top nose section
The propulsion system will have a master cutoff valve, run by a separate watchdog computer. We have talked about this for ages, but not yet implemented it. If implemented on the last vehicle, it would have dropped it from a much lower altitude.
We are going to make many changes in the electronics to improve reliability.
There will be a backup 9600 baud telemetry radio, in addition to the Esteem 802.11b.
No more solid core wire for DB connectors, move to 22 ga stranded Tefzel wire. All 18 gauge wire is already Tefzel, but I had been using solid wire for soldering serial cables, which is a known poor practice. I am moving to mil-spec double-crimp terminals for all flight hardware, instead of the single-crimp industrial terminals we have been using.
Mount all the electronics, except for the inertial unit, on a vibration isolated board.
New A/D breakout board
The breakout board that WinSystems sells for their A/D board takes up a lot more space than necessary, and uses bare wire screw terminals for input, so we are going to replace it with a custom board that is smaller and takes ring terminals.
16 signal inputs with #6 ring terminals, one ground is common to all signals measured.
The range is +/- 10V, so we need to cut the main battery voltage in half before sampling. It is a toss up if this should be done on the A/D breakout board, or on the power supply board. There should be a grid of holes for soldering in random resistors or capacitors to modify signals.
The grounds are common to all the signals, so I think all we need is a single ground ring terminal that we will run back to the power supply.
The connector going to the A/D board is a 26 pin ribbon cable with the following pinout:
1: ch0 2: ch8 3: ch1 4: ch9 5: gnd 6: gnd 7: ch2 8: ch10 9: gnd 10: gnd 11: ch3 12: ch11 13: gnd 14: gnd 15: ch4 16: ch12 17: gnd 18: gnd 19: ch5 20: ch13 21: gnd 22: gnd 23: ch6 24: ch14 25: ch7 26: ch15
Watchdog Board
Trivial microcontroller that watches a continuous signal from the main computer, and uses a private motor drive to open the master cutoff valve only when the main computer is healthy.
Input:
One optically isolated digital line from the main computer
Private +12v / GND
Output:
Two #6 ring terminals to control the master cutoff servo valve (the main computer will still read the pot feedback of that valve)
Power supply board
Multiple, diode isolated batteries for redundancy, with an additional port for running on external power
External charging ports for each battery, so the electronics don't need to be taken out of the vehicle for charging.
Short run from batteries to boards, no in-line power switch. Use the power pin on the DC/DC power converters for switch-on. Use redundant switches to prevent a switch glitch under vibration from turning everything off.
Run nothing from the unregulated power supply, except for the A/D line for current voltage level. We previously ran a couple things from the unregulated 12v supply, like the Esteem wireless unit, and the pressure transducer. It is possible we were losing telemetry momentarily earlier than the computer died, depending on the details of their power use.
Instead of running wires from the power supply board to jumpered barrier strips for distribution as we previously did, build plenty of terminals directly onto the power supply board. At a minimum:
Lots of grounds.
Unregulated +12v: Battery A/D line
+5v: computer (two lines)
+5v: 6 motor drive potentiometer feedbacks
+5v: several spares
+6v: laser altimeter
+12v: pressure transducer
+12v: GPS
+12v: Panel-PC LCD display
+12v: Several spares
-12v: Panel-PC LCD display
+15v: Crossbow IMU
We might want to use a higher voltage for the IMU, as the range is 15v-30v, and we have been warned by someone about running avionics at their minimum recommended voltages. Today's result seem to corroborate that it is closer to going out than the rest of the systems.
Current draw signal for telemetry? If we ever have a short somewhere, this would be helpful in diagnostics.
Isolated voltage signals for each battery? If we don't have that, telling when a battery has failed will be difficult.
Actuator Boards
Our current solid state relay board still has bare wire terminals (although they are high quality ones that haven't yet given problems), it still has the old power supply on it that we don't use, and one bit on the input connector is flaky, so it needs to be replaced.
Isolated voltage signal for A/D telemetry?
Isolated continuity checks for each actuator? The motor valves can be self-tested by watching the potentiometer feedback, but solenoids and pyro would need a low-current test signal. The actuator battery needs to be completely isolated from the main battery to avoid noise problems, so a continuity sensor would need to be isolated as well.
We have known needs for up to six solid state relays and six motor drives, so building for eight and eight is probably good planning.
The World's Worst Webcomic!
Rumor has it that apparently ATI was to blame, they leaked/launched the rocket before it was truly debugged and optimized. Investigation to follow.
... by the fine folks at Acme, Inc.
There wasn't a coyote strapped to that rocket by any chance, was there?
Can't check now, but I recall reading they were using a PC104 stack. They really ought to use a platform more suited to a real time control system. For this sort of thing you need lots of interrupt lines, preferably level triggered.
http://www.angelfire.com/ca3/marlowe Better a smartass than a dumbass.
Carmack makes quite a few posts to this Amateur Rocketry Board. Makes pretty interesting reading about the technical aspects of his rocket launches.
Sometimes it's best to just let stupid people be stupid.
Some of us are forgetting mentioning that they suspect that the real cause was a total power failure which in turn caused the computer to loose power and cease functioning. In the article it explains that, for some stupid ass reason, they were using slip on battery connectors...come on guys, its a rocket, it vibrates, and it appeared that the terminals came loose before ground impact which would explain why the rocket behaved as it did.
Memories become legend, Legend fades to myth, and even myth is forgotten by the time that age comes again.-Robert Jordan
..."Oklahoma Spaceport" just cracks me up.
The lecture. "The missile knows where it is, because it knows where it isn't"
I Browse at +4 Flamebait
Open Source Sysadmin
The computer died because one of the battery wires wiggled itself loose. I wouldn't really call that a 'computer malfunction'.
The computer runs Linux, by the way.
Great games
link
-- john
With that type of success i would have thought that this was John Romero's project not John Carmack's.
- MOSKIE
It's heartening to see so much interest in this flight. I mean, I can't get to it -- and I've tried numerous times. Fortunately, I've been following their work for some time. So I will make a few general comments.
OK, the rocket didn't work as hoped for. That's what experiments are for. People do these things to learn things. From this experiment they found problems with software. Problems like that can be fixed. How many times have people here written even a simple program that failed more than once while debugging was going on?
It's good to see someone with some money striking out on their own in aerospace again. We need work like this to advance the field. We need independent work to try out new ideas and drop failed paradigms.
"Beer is proof God loves us and wants us to be happy." -- B. Franklin
Is that an armadillo in your rocket or are you just happy to see me?
Anything you can do, I can do meta.
When they get up to 10 miles they're going to need to pump more fuel than an electric pump or a pressure sphere can generate. They'll need to build a turbopump and run it at its bursting point. This will require an engine redesign to recirculate propellant through the turbopump and be hundreds of times harder than what they've been doing for the last 2 years.
When they get to 20 miles they're going to need to heat the fuel beyond the melting point of their engine casing and they'll need to circulate fuel in the engine casing to cool it. This will require yet another engine redesign. There are so many problems in getting altitude that if it took 2 years to get to 100 feet it'll take hundreds of years to get to 150 miles. Anything less than 150 miles for a spacecraft just isn't practical.
As opposed to the outdated cubical rockets?
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
..they invariably piss it away on stupid shit like building a rocketship to the moon, funding the segway, buying some baseball players homerun ball for millions, donating to stop the spread of aids in india, and other such lost causes?
I don't need no instructions to know how to rock!!!!
First Movie
and
Second Movie mirrored for your enjoyment.
Your hair look like poop, Bob! - Wanker.
Computers are dumb! YEAH!
It may take them quite some time to figure it out but, I have already done the research and know what the precise cause is.
Deceleration trauma was in fact, the cause of failure.
briefly until a computer error known as a ./ effect linked it mpeg to the main page..
The war with islam is a war on the beast
The war on terror is a war for peace
severe damage (i.e., it requires a rebuild, not a repair).
We can rebuild it, we have the technology.
*This page intentionally left pointless*
Weird...
Anyone wanna have a "shitsurprise" as in South Park?? It's fun to play with shit!!
Let me guess: it took a rocket scientist to come up with that newfangled idea.
As an experimental physcist in aerospace, I've got to say that this looks real familiar. A cable that comes off in flight? Sounds just like my latest balloon flight that lasted 5 minutes after launch before a power supply failed.
The reality is that with a complicated system, there is a lot that can go wrong. 99.99% reliability on a system with 100,000 connections still means that 10 connections break in flight. This flight was unlucky in that the connection that broke was the main power cable. Next time, they'll have the watchdog on board, killing the engines when the power dies.
Good luck guys, I know how it feels. Experience is a hard teacher, but it's sometimes the only ones.
P.S.: the "Crossbow" the post talks about is an inertial guidance device. I've used those before (the cheapies, not an expensive one like this).
It doesn't really matter what OS you use if the powersupply lead shakes off at takeoff ;-(
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Posting an mpeg on the front page of /. How cruel is that?! A lot more than their rocket is going to crash.
And so is BSD, Mac, Linux, Amiga.....
You zap the moderators with a wand of humor! The moderators resist!
Die, AC.
Looks like their web server went up a hundred feet, tipped over and crashed to the ground :) All thanks to slashdot
Pull this story immediately! If someone sees it and tells Justin Timberlake, we'll never get him on one of those things!
Am I the only one who heard Roxette to sing "I'm gonna get blitzed for some sex"?
Good luck, and count me in for a ticket when the bugs are out of the system!
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
...mount the scratch monkey.
Doesn't an armadillo burrow into the ground? If so, why are they surprised that their rocket attempted the same thing? It probably developed an AI and decieded "fuck space - I'm gonna dig myself a nice little hole in the ground!"
We do not live in the 21st century. We live in the 20 second century.
The video was pretty funny not depressing as stated :) A nice fireball was missing though. Guess it's still an alpha and it'll be in the beta version.
This one. Yeah, its not Penny Arcade, Dilbert or User Friendly. Shocking, huh?
Mod me down and I will become more powerful than you can possibly imagine!
This stuff is of great interest to me, and appearantly a lot of other people who read /.
My issue is in the fact that we keep destroying these interesting sites before they can be visited by all.
There should be something done by the site maintainers to provide as little fluff as possible, while making the details interesting enough for us to read. Why waste all your alloted monthly bandwidth to put videos up when a nicely written briefing would do just as well?
I really hate the innerweb. All this wonderfull information inundated in a flood of ignorant pictures, sounds, and videos, only because its not convenient to read... oh no, we need moving pictures and sound to take us someplace that we don't have the damned gumption to go on our own.
What a sick society of Ark-B passengers we have become.
I don't sm^Hpell so good.
That sucker's been Slashdotted! All I'm getting is a message saying:
Too many users... blah blah blah
Probable cause: http://www.slashdot.org
Try again in a few seconds...
-xian@idsoftware.com
Looks like more than one thing crashed over there...
"We demand rigidly defined areas of doubt and uncertainty!" - Vroomfondel, H2G2
Did the 'computer failure' kill the hard disk?
Was there something wrong with his copy of real life?
Or is it, as I personally have long suspected, that real life is in fact different to Quake?
Hmmm... That would certainly explain my inability to get a working BFG-9000 from ebay...
I saw "untethered test flight" and immediatly tried to picture a "tethered" test flight using some sort of rope to the ground. Not that different a trajectory from this flight.
Do they really call ground mounted engine fires tethered flights?
Or does tethered flight mean under wing or pull along flights?
What is a tethered flight?
He was going to use the NGLM (Nail-Gun Launch Mechanism) but it's still in development..
-- jimmycarter
"NOVEMBER SKY" doesn't translate into anything nearly as cool as "ROCKET BOYS."
I mean, according to anagram science, Carmack should have been asking his girl to "SERVE MY KNOB."
"And like that
This is what happens when you miss the timing on a rocketjump.
We built a checklist for our flight operations, which was a very good idea. Going through it before setting off caught several things we almost forgot.
Except the one thing that you did forget.
Haing a checklist is one thing. Having a complete checklist is evidently something else.
Comment removed based on user account deletion
http://mi6hq.dyndns.org/bunker.mpgd yndns.org/flightUnsuccessful.mpg
.. my server maybe @rr.com .. but on a commercial account it should be able to take it.
http://mi6hq.
Enjoy
Is that thing suppose to actually be able to fly? Whats with the base of that thing? There's no fins, just a big skirt.
It brought back memories of the Junkyard Wars Christmas Tree rocket. It also reminded me of an 8th grade science project in which a fellow classmate built a rocket according to Wylie Coyote specifications with an nose cone that was significantly larger than the fuselage - it went about 20 feet and landed on the roof.
After carefull debugging of the code and scripts used for controll of the rocket motors it was discovered that Carmak used the script for the landing pod in Quake 2 .. hence it's crash ...
Comment removed based on user account deletion
You're lagging out tons of people on id Software's game servers by /.'ing armadilloaerospace.
Oh the humanity.
probably not the best behaviour for a space ship.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
second
-- john
Who forgot to carry the 1 in the calculation this time?
We built a checklist for our flight operations, which was a very good idea. Going through it before setting off caught several things we almost forgot.
Hello? Do you think so? Why do you think pilots who have been flying for 30+ years go through a checklist before every single takeoff? Seems like the notion of a checklist would be so self-evident from the start -- saying "hey, we thought it would be a nifty idea to create a checklist" makes me wonder about this operation.
It also sounds like the checklist ought to be updated to include things like "check all connections thoroughly after long and rougher-than-anticipated transport of vehicle."
Does anyone remember seeing footage of early attempts at launches from the '50s (Vanguard etc...)?
Many of them did the same thing. Went up. Arced over. Went Down.
Fascism starts when the efficiency of the government becomes more important than the rights of the people.
Bunker.mpg (mi6hq.com) flight Unsuccessful.mpg (mi6hq.com) My second try for posting mirrors of mpg files. now with html tages (Because it's so hard to copy and paste or highlight and middle click)
estes!
Just raise the taxes on crack.
It's given that they're using a computer for control. So they should use the right computer.
http://www.angelfire.com/ca3/marlowe Better a smartass than a dumbass.
Where Reid Malenfant builds his rockets and decides to exploit the solar system ressources with a pregnant octopus driving the shuttle. In the story, NASA is completely oppose to malenfant's venture.
I wonder how far the book really is from reality after seeing the story.
But any how, it might not be a bad thing to see independant minds leaning on such a problem, especially without any government involved.
Pressure fed rockets can achieve significant altitudes, just look at the Scorpius and Beal efforts. France developed and launched a pressure fed orbital launcher years ago. No turbopumps are required at all.
Even if pumps are decided to be used, there are a couple low-tech alternatives to turbopumps that have been demonstrated in the past ten years, the ASTRID piston pump and the Flowmetrics Pistonless Pump come immediately to mind.
There's also the gas generator to be considered, basically pressurizing the propellants with a specially designed slow-burning solid rocket motor or a slow peroxide feed on a catalyst pack connected to the main propellant tanks.
Turbopumps are old tech!
...and I can prove it!
1. There are no exhaust flames.
2. There is no exhaust crater.
3. The shadows are all wrong.
This proves they never went to Oklahoma!
I like the way it flies neatly over the guy in blue jeans. You can see him just at the end of the clip. I can't tell looking at the clip if he's mission control or just some guy having a barbeque. My compliments to the Oklahoma Spaceport's range safety officer.
Equine Mammals Are Considerably Smaller
... they should've waited for the point release!
(Score:-1, Wrong)
"Rocket Flight DOOMed, But Not Due to Leak."
I love their current default overflow page Too many users... blah blah blah Probable cause: http://www.slashdot.org Try again in a few seconds... -xian@idsoftware.com
When MOD PARENT UP isn't good enough.
Their site is getting slooowww, here's a mirror of the report itself (not the movies).
Excellent job boys, call up those investors and get us another few million to blow on parties!
which is about 30 miles away from the launch site. I know the gentleman making the rocket engines - he is based in OK, and a second generation engine has already been designed. If you really are interested in asking him about the design, his name is Doug Schones, and his e-mail is "dynaturn@iltnet.net" I am following the developments of this space port very closely ( hopefully I can land a job out there someday), but IMHO this area will never develop the way our legislators would like. This Amarillo guy is so essentric that common sense doesn't speak to him, God Bless Him.
It was due to a design failure.
The rocket appears to be unstable, which is to say that the center of gravity is behind the center of pressure. Looking at the pictures, it's not too surprising. The vehicle is too short vs. it's diameter, and the flared base isn't big enough to stabilize it (i.e. not big enough to push the Cp back behind the Cg of the vehicle).
I imagine that Carmack etc. knew that it was aerodynamically unstable and counted on active feedback controls to compensate, which was their primary mistake. By doing so, they greatly increased the critical complexity of the system, which is to say they increased the number of things that would kill the vehicle if any one of them failed.
It would have been far better to design for simplicity and graceful failure by building a vehicle that is aerodynamically stable. Someone forgot KISS.
I guess I shouldn't be surprised -- this is what happens when you let programmers design rockets.
"Research is what I am doing when I don't know what I am doing." -- Wernher von Braun
I'm sure I can rocket jump higher than this!
The test vehicle got a few hundred feet up before turning into the ground. That's a few hundred feet higher than the X-33 got with about $1 billion of funding.
Rocket engineering should be like that. 'Crash and learn' is a much more productive use of time and money than 'here are the viewgraphs that your last billion dollars bought.'
The other thing that scared me was the use of slip-on battery terminals and the like. I don't even install stuff in my car without soldering the connections. WTF are these guys thinking, using Radio Shack-grade interconnect hardware in a fucking ROCKET?!?
:) Based on his report of this launch attempt, he's got some expensive lessons ahead.
You can tell that Carmack's just spending his way up the same learning curve that a bunch of the rest of us po' kids climbed the hard way.
They should have used a ATI VPU (or NVIDIA GPU).
Carmack realy knows how to program those things!
16,777,216 comments ought to be enough for any forum!
I hope Im not the only one who caught the real genius reference....
"Would you classify that as a design problem or a launch problem?"
Just think of all the crazy stuff that'd be happening now if they were called Donkey.
Smooth, guys. Way to slashdot the website of the entire State of Oklahoma.
Free messageboards and more! Your girlfriend's seen myWang
YES a windows xp rocket, if only we could have 256 megs of ram in it.
"Its defense mechanism is to jump straight up when frightened, and adults can jump three to four feet into the air. "...
So the rocket is named after an animal that can launch itself in the air, up to a few times its own height, then crashes back to earth, possibly causing massive destruction and carnage.
Guess they picked the right animal after all.
when I read the title I thought, "Cool! Flying armadillos!" and then I read on and I read the word cannon, and I damn near shouted "SWEET! They're shooting armadillos into the sky!" -- it wasn't until I read the article that I was totally disappointed...
I feel guilty every time I boot Windows
Luck (and yes I *mean* luck as in the fortuitous random gift ot fools) has gone to this guy's head--he now thinks he can conquer anything. His failure here shoudl be a wake up call: beign a good programmer doesn't make him an ace at everything just as being a good actor doesn't make Robert Redford an expert on the environment nor Jane Fonda an expert in political science. Learn some humilty man before you really make an a*s of yourself.
I used to hate computers, but then a server went down on me.
They should have waited for the Point Release.
that's what I use
yeah and nasa never had a rocket crash in the early days?
Puh-leeze. The whole point of Armadillo's design is to use computer-controlled active feedback . Their goal is VTVL with goodies like auto-hover and sideways crabbing. At this stage, they couldn't care less about aerodynamics. That's for the next vehicle.
I concur, this design should be fixed to make it stable for moderate angular deviations. They can still fly it unstable, but only if they have the control power necessary to correct for reasonable deviations from vertical. It looks like the thing went completely unstable due to the small deviation on liftoff.
Presuming that they did plan enough control power to correct for these instabilities, the other alternative could be that one corner nozzle was damaged on lift-off.
Four large fins off of the bottom flange should be enough to remove the instability I think. They have to be really large for that squat a body though. Why not lengthen the rocket guys?
---- Luke "To boldly go where no one has gone before..."
Oklahoma, Louisiana, and New Mexico the only states remaining that allow legalized cockfighting. Who says Okies have no culture. Why not televised cockfighting in space to raise money for the Okie space program. Yeah! Go Sooners!
Christ Carmack, stop fucking around. Slip on battery connectors fer chrissake?! Jesus.
I have been following these guys for quite some time and have been frustrated by their slipshod approach to quality. It seems to be borrowed from the software world, were a failure neccessitates nothing more costly than a recompile. I have seen Carmack, time after time, subject thousands of dollars of equipment to risk because of cheap equipment and lack of thorough/rigorous testing.
This is not the first time they've had problems with computer equipment. Last time there was some overheating - because guess what - rockets get hot. Apparently this was just a messy implementation detail that Carmack overlooked.
They've also had problems with an 'altimeter' which was designed for hand held distance measurment (a la a laser speed-gun) - never designed to operate on a hot accelerating rocket. The thing has caused innumerable problems for Carmack due to it's flaky behavior. As far as I know he is still using it, even though it's caused crashes in the past. Why? The real thing is too expensive.
Additionally their testing is erratic and has insufficient controls. Often times between tests Carmack will change serveral variables, run a test - get weird results, and be left scratching his head as to what caused the change. In the real world you try to change as much as possible between tests - that way if it breaks, you know what caused it, without additional testing.
And no, I am not saying I could do it better. Most of these guys are far smarter than I. But it doesn't take smarts to implement some simple practices from the real world of engineering. I hate to see their time, effort, and intelligence wasted on wholly preventable failures like a computer cut-off caused by 'slip-on' battery connectors.
-josh
You realize that all current rockets are inherently unstable in the way you describe? I.e. the thrust is all at one end and has to be carefully controlled to keep it pushing through the Cg. If anything, this rocket is substantially
more stable than the Saturn V precisely because the Cp is at least close to the Cg (and so small errors in thrust direction act on a small moment arm and induce a correspondingly small rotation).
Tug-type rockets (think two thrusters on a frame at the top of the payload with their exhausts directed down past the payload, just like James Bond's jetpack) will be practical and enormously easier to control when they operate entirely in outer space. The need to be aerodynamic puts a kink in their use as a lift vehicle (don't think NASA didn't consider it).
Regards,
Ross
I don't mean to sound like a Carmack fanboy or that he's above criticism, but when you've actually built something that lifts a man off the ground, hovers, and then gently goes back to the ground on a shoestring budget, then I might give a shit about what you say.
From the video, the rocket looked extremely stable until the computer malfunction.
Carmack is generally recognized as a genius. What are your credentials?
I'm not 100% sure that's true. Rockets are only aerodynamically stable, if at all, above some certain speed. It sounds as though this one may never have reached that speed, and much of the electronics seems to have failed very early on.
The guy, whatever his name is, seems to specifically allude to the rocket being stable because he says that in the event of an IMU failure, the main engine can continue to fire provided that the rocket is in the air and on an upward trajectory.
I wasn't able to watch the video, but I did read the post that reproduced the failure analysis.
MM
--
By including this sig, the copyright holders of this work or collection unreservedly place it in the public domain.
+++ath0
Soldering a wire directly to the battery terminal is not a "Good Thing". When the solder hardens, it creates a point between the hardened solder soaked wire and the solder free wire. This, under vibration/stress leads to a clean fracture/break.
Mill specs require you _not_ to solder directly to this type of connection. Instead double crimp (but don't over crimp) the wire to a mechanically fastened connector.
so anyhow mister smarty pants, your dry humor was inaccurate and thereby makes me laugh at you, and not with you.
-malakai
-Malakai
A Dragon Lives in my Garage
Black Electrical Tape
So, could we assume that the project was DOOMED from the start. yuck, yuck :-)
but when you've actually built something that lifts a man off the ground, hovers, and then gently goes back to the ground on a shoestring budget
They *didn't* do that. I could probably never do that. All they did do was make a 4 foot unmanned rocket that got off the ground, did a flip and fell over. Granted they did this with shitloads of machinery to correct aerodynamic problems, but hell I can do that on a shoestring budget and NO fancy machinery.
That's a spaceport? It looks like the soccer field behind my middle school.
Yes, they did. Look at some of the earlier successes.
That's not true. Almost every programmer has produced at least one, usually dozens.
Many of them say "Hello World!"
That what was all this school was for... to teach us how to solve our own problems. -- janeowit
requires a good mechanical connection before attempting to solder. The general rule is that it should work without the solder. Of course this isn't always practical, in fact surface mount is just held on by the solder. Rules are made to be broken! lol
and
They obviously know about where the center of gravity should be relative to the center of pressure, but how do you generate pressure when your rocket is just lifting off?
I think I saw that one.. They were using standard solid fuel model rocket engines. Those things just tend to work (unless you make them yourself!). They also have a high initial impulse which gets them traveling in the right direction quickly making the tail fins functional. Basically, they just built big toy rockets. This beasty is an early prototype for a rocket that will fly into space. There is quite a diffrence.
Nah. I think they where just going for the "Rocket Jump". But as everyone knows, Rocket Jumps are fun, but get ya burnt
Excuse the Unicode crap in my posts. That's an apostrophe, and slashdot is busted.
Your just mad because he's smarter than you are.
This isn't a scaled up Estes rocket; analyzing it
as one is a mistake.
As other replies have pointed out, "real" rocket
launch vehicles are aerodynamically unstable
or only stable over limited ranges of flight.
Even if this sized rocket could have been made
aerodynamically stable, they are building towards
larger vehicles and in particular, vertical
takeoff vertical landing which absolutely requires
full 3 axis stabilization and control authority.
Think the DC-X VTVL experimental test rocket.
Carmack has alluded repeatedly to it being
a dynamics and flight operations precursor to
what he's trying to do.
Also, the instability was probably due to a long list of things, possibly most important being the failure of the flight control computer.
However - some aero stability work would only help the control system do it's job, and the current design just looks highly unstable. Even large angular deviations would be immensely helped by fins, and unless you need huge roll _rates_, which come with commensurately huge control power requirements, why fly without the fins?
BTW - I'm a big fan of this effort, my armchair quarterbacking comes purely from a desire to help. In fact, If I get time I'd like to do some gratuitous CFD work for them...
---- Luke "To boldly go where no one has gone before..."
I'm not with Xcor any more.
"Research is what I am doing when I don't know what I am doing." -- Wernher von Braun
Not to be an asshole, but there are lots of CalTech graduates around, as well as lots of former aerospace engineers (presuming you're an engineer, which you don't even claim).
If you had claimed to be "the principle designer of the XX rocket" or something along those lines, then it would mean something. As it stands, you're just another voice bagging from the sidelines.
I mean, did it ever occur to you that they intentionally made it somewhat unstable to be a better test of the flight control hardware? Did it ever occur to you that this was a TEST vehicle?
If they wanted to launch a model rocket with better guarantees of reliability, I'm sure they would have designed it differently.
Like I said, I don't want to seem like a Carmack fanboy or that he's above criticism. But snide little posts from people who could never get within a light year of what Carmack's already accomplished really irritate me.
As a aside, I think it will be really amusing when Carmack's small, low-funded venture beats XCor's well-funded mongolian-hoard venture to the X-Prize. :)
If you had claimed to be "the principle designer of the XX rocket" or something along those lines, then it would mean something. As it stands, you're just another voice bagging from the sidelines.
I have done injector and combustion chamber design for rocket engines up to 2400 PSI chamber pressure. Furthermore, my designs were built and test-fired, which is something that few aerospace engineers under the age of fifty can claim.
Really, though, my qualifications are irrelevant to my original point, which was basically that they did not observe the KISS principle. Keep It Simple, Stupid is the first principle of good engineering design, regardless of the field in question.
As a aside, I think it will be really amusing when Carmack's small, low-funded venture beats XCor's well-funded mongolian-hoard venture to the X-Prize.
This is funny as hell to me. Xcor has done everything they have done (including the first privately-built rocket powered, piloted airplane) with something on the order of a million in funding over the last four years. They are the small, low-funded venture.
Oh, and by the way, it's Caltech, not CalTech.
"Research is what I am doing when I don't know what I am doing." -- Wernher von Braun
Systems have sub-systems and sub-systems have sub-systems and so on ad
infinitum -- which is why we're always starting over.
-- Epigrams in Programming, ACM SIGPLAN Sept. 1982
- this post brought to you by the Automated Last Post Generator...