In the Shadow of the Moon
In the Shadow of the Moon, extra footage
Posted on 04/19/2015 2:52:20 PM PDT by BenLurkin
Billionaire biz baron Elon Musk has revealed a few more details about why SpaceX's latest attempt to land a rocket in one piece at sea had failed.
The Register reported on the drama as it unfolded on Tuesday. Once again, Falcon 9 successfully launched the capsule payload to 'nauts on the International Space Station, only for the rocket to hit the "just read the instructions" deck hard on its shaky return to Earth.
(Excerpt) Read more at theregister.co.uk ...
Bump
I’ve watched some videos from SpaceX, including the Dragon2 roll-out. In there he shows one of the capsule’s RCS thrusters. They are very small - wouldn’t take much space or weight to put them at the top of the booster. That would give the control system some much needed moment to stabilize the vehicle.
“The software that controls that rocket has to bring the solutions of five or six differential equations all to zero at exactly the same instant in time. “
Like Neil Armstrong did when he landed Apollo 11 with a watch’s worth of computer helping him?
Willing to give them more time but gotta admit I’m not impressed by Falcon.
Having done a lot of RC model helicopter flying, I agree with you.
Except add these challenges: the COG of the helicopter is about fifty feet above the skids, and the helicopter’s moment of inertia is about twenty times more than what you’re used to.
A larger pad would cut down on the need for lateral positioning. Seems like they missed the pad, had to juke to one side, and lost control in the process. If the barge/landing area was larger, maybe they could have saved it.
Willing to give them more time but gotta admit I’m not impressed by Falcon.
I take a back seat to no one in my admiration of Neil Armstrong and the job he did landing Eagle on the surface of the moon.
Neil Armstrong was almost literally a superman. He was the product of a rigorous selection program. Among test pilots he was superstar, similar in talent level to an Olympic athlete or a Carnegie Hall level musician.
That said, Cdr. Armstrong didn't have to deal with wind as he approach the moon, and the lunar surface wasn't pitching and rolling as he did so. Also, the center of gravity of Eagle was much closer to the spacecraft's landing plane than was the SpaceX rocket.
But no doubt in my mound that Neil Armstrong was an amazing pilot, an amazingly good master of man-in-the-loop control systems, of which he had been a designer if I'm not mistaken.
Also, in the SpaceX case, they had to bring yaw and pitch angles and yaw and pitch angular velocities to zero at the same time that they got velocity and vertical rate of decent to zero, with fuel running out at the rate of pounds per second.
I do not understand how this will save any money. Swapping payload weight for return fuel weight does not help the launch vehicle company make a profit. “We got our first stage back safely but we were not able to put enough payload into orbit to make a profit.” That is why the traditional launch vehicle companies do not try to save their boosters.
Isn‘t Elon Musk an aftershave lotion from the 1970s?
Well, I think we both agree he’d have handled all that too... and arm wrestled his co-pilot at the same time.
I assume it’s cheaper to lose the vehicle than to test components thoroughly enough. I mean adding, say, a grand in testing to the cost of every hundred dollar part is something only human life justifies.
Yes. I switched to that from Hai Karate.
Lol. Did you need to learn how to fend off the ladies with those karate chops?
Here is one of Neil's training flights before he landed on the moon:
Apollo 11: Neil Armstrong Lunar Landing Test Vehicle (LLTV) Crash (May 6, 1968)
Thanks.
That’s one weird bird.
That was “The Flying Bedstead.”
It had controls similar to what they had planned for the lunar lander.
It also had a big jet engine on a gimbal; the jet engine was sized to overcome Earth’s gravity in the vertical direction. Its thrust vector was aimed by slaving it to a gyro-stabilized platform.
Then there were a bunch of thrusters that were laid out in a manner similar to that planned for the lunar lander. The whole system was tuned to have a dynamic response similar to that of the actual lander.
The idea was that Apollo lander pilots could practice on Earth. The whole thing was a kind of simulator, built long before computer power was sufficient to build a software-only simulator.
It would appear (from that video) that one of the control loops didn’t respond well to a transient. It looked like when the pilot (Armstrong?) “gunned it” to try another approach, the main engine control loop slowly “walked” off vertical. I’d like to know what actually happened. Perhaps the documentation is on the internet.
Oh, the answer is much simpler than I thought.
The investigation board determined that the fuel for the attitude rockets ran out, which is what caused the crash.
Perhaps the pilot realized he was out of thruster fuel and hit the throttle to gain altitude before ejecting.
It started to flip on him, he bailed out one second from death, was unhurt upon landing, and went back to the office and started his report. “Heard you bailed out.” “Yup.” ;’) There’s a reason he was picked for the first lunar landing. :’)
This landing butt-first technique is crucial to saving money, mostly for later models of rocket. Musk’s goal is recycling a much heavier booster for Mars missions. SpaceX changed its engine development for the next-gen Merlin from RP-1 to methane, because RP-1 isn’t available on Mars, but methane is. Mars also has no infrastructure, so perfecting the fin-tip landing will pay off when the colony ships start going to Mars — they’ll be oriented for launch, merely requiring refueling from local resources. In order to perfect this technique, they have to practice it until they can stick the landing every single time. So far they’ve only tried it twice or three times, and scrubbed it for their previous launch for some reason or other.
It’s remarkable that SpaceX has gone from a glint in his eye to the state it’s in today, but each time they hit some milestone believed to be difficult at best, it shows what singleminded, intelligent leadership can do in a company. I was among those who shook heads when the early launches from some flyspeck Pacific island had to be scrubbed, or the rockets exploded and whatnot. The company has been around 12 years, as in *only* 12 years. I was impressed back when Beal went from drawing board to the second-largest liquid-fueled engine in history in maybe five years, and in a way Beal’s experience helped pave the way for Musk et al, but it is a bit devil-may-care to doubt that Musk knows what he’s doing.
A couple years ago, an article about SpaceX recounted how, early on, they were going to subcontract for parts to the small aerospace feeder companies with deep experience. When those companies gave them quotes, they changed their minds. Then as the launch business slapped everyone around a bit, those feeder companies approached SpaceX with lower bids. “Oh, we went ahead and built it ourselves.” Buh-bye.
SpaceX is using engines fabricated on a 3D printer.
In the Shadow of the Moon
In the Shadow of the Moon, extra footage
Plus it looked really cool in the old sci/fi movies from the 50's and 60's.
Sorry, couldn't resist and it's late :)
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