SpaceX rocket landing attempt

  • #1
GiantSheeps
83
7
So SpaceX is going to try to land a rocketship on a boat... That's pretty amazing, if you ask me. Does anyone know of a TV station that will be broadcasting the event live? I know I could watch it here http://www.spacex.com/webcast/ , but it would be nice to be able to see it on the big screen with the whole fam
 
  • Like
Likes Greg Bernhardt

Answers and Replies

  • #2
phinds
Science Advisor
Insights Author
Gold Member
2021 Award
18,018
10,513
Geez ... that IS amazing. Very surprising that they are even going to try it and even more surprising that they put the odds of success at 50% (at best). Still, they know its capabilities a lot better than we do and wouldn't be trying it if there were not at least some reasonably chance of success.

Seems that landing leads to another problem though ... say it works. THEN what ? How do they get it back onto land?
 
  • Like
Likes GiantSheeps
  • #3
GiantSheeps
83
7
Seems that landing leads to another problem though ... say it works. THEN what ? How do they get it back onto land?

Ooh I hadn't thought of that. That whole process might actually be as exciting as the landing (if the landing is actually a success of course). That would be horrible if the landing was successful and they damage the rocket when they are trying to bring it back onto land
 
  • #4
enorbet
481
85
Actually it seems they have accounted for that by recognizing this is a process and that there are bound to be failures along the way, but that also we often learn more from failures than successes. People can say whatever they want to about Elon Musk but I like his cool blend of dreamer and practical "hands on". He sees Problem - Booster stages are where much of the money goes and we throw it away because it is difficult to not throw it away Solution - Find out just how difficult that really is and see what that reveals for a 2nd step and narrow down. The payoff is quite literally astronomical.
 
  • Like
Likes GiantSheeps
  • #5
Garth
Science Advisor
Gold Member
3,579
107
we often learn more from failures than successes.

Thanks! That makes me the cleverest man in the world...
Garth
 
  • Like
Likes Mike1220 and Dr.Physics
  • #7
enorbet
481
85
Despite the crash ( or RUD, if you prefer :P ) it appears a simple problem to repair. As anyone could see there was a problem with attitude as it was at nearly a 45 degree angle rather than perpendicular. Apparently a simple hydraulic system or it's controls failed to do it's job at fin guidance. Redundancy caused the engines to attempt to compensate but it was too little, too late. It is praiseworthy that they hit the barge on target. I doubt it will take much to fix this last wrinkle. Overall as experiments go, quite successful as it lends credibility to the idea that it is by no means an insurmountable problem even with present technology.

Here's the link -> http://www.popularmechanics.com/how-to/blog/spacex-falcon-9-reusable-rocket-failed-landing
 
  • Like
Likes mheslep and GiantSheeps
  • #8
GiantSheeps
83
7
Yeah, and from what I understand they're going to make another landing attempt on the 29th, it seems like the chances of success on this one are wayyyy higher than they were before.

I might have misread that though and I don't remember where... Can anyone verify that they are in fact going to attempt another landing on the 29th? I know that they do have a launch scheduled for that day...
 
  • #9
mheslep
Gold Member
360
728
it appears a simple problem to repair.
Musk identified the problem as a 10% shortage of hydraulic fluid. If this was a simply problem to fix, then why wasn't it identified earlier, i.e. add an ample margin of fluid, unless the vehicle mass margin is too tight allow such? If that's the case, then adding more fluid won't be simple.
 
  • #10
cjl
Science Advisor
1,967
551
They probably thought they did have an ample margin, and more control effort was required than expected. They'll probably just add more for the next flight.
 
  • #11
mheslep
Gold Member
360
728
They probably thought they did have an ample margin, and more control effort was required than expected.

I could see that being the case if the control profile left expectations; that is, PID control degenerated into some kind of bang-bang oscillation. If that's the case, then fluid store is not the fundamental problem.
 
  • #12
cjl
Science Advisor
1,967
551
It's also possible if their plant or dynamic models were a bit off. It doesn't require a dramatic oscillation to eat into aerospace-style margins.
 
  • #14
mheslep
Gold Member
360
728
13 mins 35 34 33 ...
 
  • #16
36,167
13,154
And liftoff!

The first stage separated, the second stage is firing, they will try to land the first stage again in a few minutes.

Edit: Second stage engine cutoff and separation.
Dragon has unfolded its solar arrays.
 
Last edited:
  • #17
berkeman
Mentor
63,603
14,722
Ack, they stopped the live feed and said to check social media for the live landing site action. Facebook is not showing me an obvious live feed. Anybody got a link to a live landing site feed?
 
  • #20
mheslep
Gold Member
360
728
Arg. Wind responsible for "excess" velocity? A 10 m/s wind places more than a half ton of force on that cylinder (~3.7mx30m), meaning it might have to come in with a tilt into the wind. I don't recall any indication of wind velocity on those multiple ground landing tests in Texas.

Barge drift with current/wind? Though barge station keeping is routine.
 
  • #21
mheslep
Gold Member
360
728
The vehicle appears to have incurred a ~20deg tilt from vertical with a single vehicle height remaning above the platform. Last moment positioning correction, or wind forcing? I see white caps on the water so there was at least 10 m/s wind on the surface, higher a couple hundred meters up. I can't see how they avoid some maneuvering thrusters (couple hundred N) at the top of the lander if wind is the problem, as gimballing the engine has against the rotational moment of that lander must be too slow? Only minimal thruster fuel required, in the last few hundred meters before landing. I suppose the mass of the thrusters (minimum two?) would be no trivial matter when every kilo of payload means 98 kilos of rocket.

Descent velocity also seems a bit faster than the Texas tests. Looks like ~30 m/s at 30 m if the video is real time. Descent velocity did zero (apparently) by the time it hit the pad, but that velocity at 30 m also means almost no time to correct lateral velocity - which Musk noted was high. Lateral velocity correction means a vehicle rotation with this scheme, which per above is not quick.

blob:https%3A//vine.co/b77664ce-5826-4c4f-b694-4fe24a0ac215
 
Last edited:
  • #24
Dotini
Gold Member
635
231
Space X has exploded a few minutes after launch.

Watching the press conference, I gleaned the following:


- They have a serious problem. They have 4 months of supplies left on ISS. The crew will be returned when they are down to 45 days.

- Water and water filtration and provisions are probably the biggest loss to the ISS. And the docking adapter and radio system. Russian Progress and Soyuz flights are pending, as is one from Japan later in the summer.

- The ISS water processor is reaching its limits.

- All three commercial vehicles to ISS (Orbital, Progress and Space-X ) were lost in a one year time frame.

- Stand-down of Musk's rocket until problems are understood.

- FAA will have oversight of the investigation which will be conducted by Space-X, which operates on an FAA license.

- Commercial crewed vehicles are paused and under scrutiny, as are budgets. But they want to continue with the concept. Boeing is working on one.

- The Russian Progress launch which adds crew to the ISS is still on for next month.
 
Last edited:
  • #26
Dotini
Gold Member
635
231
Damn !
No kidding.

I was watching very carefully on a 27" HD screen. At about 2:19, the 2nd stage appeared to ignite while the 1st stage was still thrusting. I could be wrong about that, but the ensuing explosion filled my screen, and the sky filled with smoke and debris. Musk identified a 2nd stage oxygen tank overpressure, but not as the root cause.
 
  • #27
36,167
13,154
SpaceX had such a good track record :(. The first stage landing looked like a problematic part, but I didn't expect that.

One failure out of 19 launches is still the average ratio, but it will certainly delay several things significantly (including the idea of manned launches).
 
  • #28
tom aaron
124
38
SpaceX had such a good track record :(. The first stage landing looked like a problematic part, but I didn't expect that.

One failure out of 19 launches is still the average ratio, but it will certainly delay several things significantly (including the idea of manned launches).

It's 2015.

There are 3 humans in LEO on the ISS. Another rocket failure.

A much needed reality check as people talk about a successful Mars mission by 2040. Our technology is nowhere near any such time line for a trip to Mars. We can barely service 3 astronauts in LEO.

The Shuttle was touted as the most advanced machine ever made. Buzz Aldrin criticized it for exactly that reason. The ISS, the Shuttle, the JWST...victims of technologies that have frenzied and eaten up resources far beyond what they were designed for.
 
Last edited:
  • #29
rootone
3,393
946
... the 2nd stage appeared to ignite while the 1st stage was still thrusting.
It looked like that to me as well, but it could be just 'appearance of'.
If that actually happened, it's hard to believe. That is that something as simple as an incorrect timing of scheduled events could explain it.
 
Last edited by a moderator:
  • #30
36,167
13,154
A much needed reality check as people talk about a successful Mars mission by 2040.
You can stop progress completely with reality checks that are pessimistic enough.
2040 is 25 years away. 25 years before Apollo 11, the first unmanned V2 rockets reached space (but not orbits).
We can barely service 3 astronauts in LEO.
3 to 6. We can, but sometimes we might have to send more rockets than planned because no technology is 100% reliable.
 
  • #31
tom aaron
124
38
You can stop progress completely with reality checks that are pessimistic enough.
2040 is 25 years away. 25 years before Apollo 11, the first unmanned V2 rockets reached space (but not orbits).
3 to 6. We can, but sometimes we might have to send more rockets than planned because no technology is 100% reliable.

Man on Mars maybe by 2075 or so.

Apollo is peanuts next to a Mars mission. Also, there is not a technological infrastructure ready to take on such a mission. There are not warehouses full of engineers and other warehouses full of piles of money all ready to start churning away if the President and Congress gave the green light.

We are at stage zero. No launch vehicles, no spacecraft , no habitation, no anything. Stage zero. We are grasping at straws trying to just find a reliable means of servicing an orbiting ISS.
 
  • #32
phinds
Science Advisor
Insights Author
Gold Member
2021 Award
18,018
10,513
Tom,

The whole Mars landing thing has been totally beaten to a pulp on this forum. Try a forum search. I think the consensus agrees w/ you. I certainly do. There are a few Pollyannas who still think it may happen in the next couple of decades but I'd like to have some of what they're smoking.
 
  • Like
Likes Dotini
  • #33
36,167
13,154
Apollo is peanuts next to a Mars mission.
So is a suborbital rocket compared to Apollo.
No anything is the situation of 1944. Now we have things. We launched missions to Mars - we even set up a communication infrastructure there for the rovers. We launched humans into space. We assembled things in orbit. We had humans living in space for more than a year at a time.
Mars is heavier and much farther away than the Moon, sure. But we have much more than the Apollo program had in 1944. It would need a strong political will, for sure. Not necessarily from the US.

I'm not saying it will happen, but I cannot rule it out. In the same way you probably would have claimed in 1944 that a manned mission to moon within 25 years is completely impossible.
 
  • Like
Likes mheslep
  • #34
tom aaron
124
38
So is a suborbital rocket compared to Apollo.
No anything is the situation of 1944. Now we have things. We launched missions to Mars - we even set up a communication infrastructure there for the rovers. We launched humans into space. We assembled things in orbit. We had humans living in space for more than a year at a time.
Mars is heavier and much further away than the Moon, sure. But we have much more than the Apollo program had in 1944. It would need a strong political will, for sure. Not necessarily from the US.

I'm not saying it will happen, but I cannot rule it out. In the same way you probably would have claimed in 1944 that a manned mission to moon within 25 years is completely impossible.

I don't know why anyone in 1944 would have said a manned mission to the Moon was impossible. It was within the engineering capabilities of known rocketry at the time. Engineering is not magic but rational application of technology.

Rovers are machines. Not organic human beings. There is no technology to send a man to Mars, get him there in a healthy state, sustain him for a stay and then return him to Earth. There are not teams of researchers available to do the basic science, develop the necessary technologies. We can barely recirculate water in the ISS for a few months without resupply...there is no room for error on a Mars mission. You don't need one water processing back up system but 5...and they all need to be tested in Martian conditions. Multiple pre human landers would be necessary, redundancies...pre mission non manned flights. None of which we have a scrap of technology to do.

In the 1960's there was an infrastructure of 'dirty hand' engineers who emerged from WW2. This is why the advances in nuclear energy and delivery systems was even more phenomenal than the Space missions. This type of infrastructure does not exist today. There are thousands of pieces of a puzzle that need to be developed and brought together...by who?

The JWST is minuscule in technological needs compared to a manned mission to Mars. It's a decade behind schedule and multiple times over budget. Multiply this a hundred times for what is needed to sustain a manned mission with zero room for error.
 
  • #35
mheslep
Gold Member
360
728
... We are grasping at straws trying to just find a reliable means of servicing an orbiting ISS.

That assertion doesn't really survive a reality check given the ISS has continuously occupied for the last 14 years. One might as well resurrect "man was not meant to fly" come the next canceled plane flight.
 
  • Like
Likes clope023 and mfb

Suggested for: SpaceX rocket landing attempt

Replies
32
Views
2K
Replies
11
Views
960
  • Last Post
Replies
11
Views
2K
  • Last Post
Replies
15
Views
4K
  • Last Post
Replies
9
Views
1K
  • Last Post
2
Replies
42
Views
3K
  • Last Post
3
Replies
85
Views
11K
Replies
2
Views
2K
Replies
12
Views
2K
  • Last Post
Replies
13
Views
813
Top