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SpaceX Attempting 1st Stage Landing After Rocket Launch (AKA Crazy Space Stuff)

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L

Lucky Forward

Member
falcon-9-barge-landing-kaboom-2015-01-16-01.jpg
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.
 
F

fallout

Member
jett said:
That's too bad, guess they miscalculated. Did someone at SpaceX use imperial instead of metric? :p
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Given that they're trying to reuse the rocket for the purposes of saving money, I imagine they're hoping to keep the amount of consumables down to the bare minimum. It's entirely possible that they would have had enough under different conditions.

I also think that their "ran out of fluid" explanation is probably a little light. There could be some logic errors or something that contributed as well.

Yeah I know, I guess the footage just makes it look like a horrific crash.
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It is a horrific crash. Basically, you either land it or you don't. I guess you could land it and it might tip over, but even then, that probably wouldn't be pretty.
 
L

lordxar

Member
Damn that was close. Haven't followed space related progress since the Shuttle was retired for more than a cursory glance at whatever failure the news showed. Need to keep an eye on SpaceX I guess, looks like their doing some good sciency stuff failure or no.
 
L

Lucky Forward

Member
^ lol

jett said:
"Close"? I guess it crashed where it was supposed to land, but that seems like a disaster to me. I wonder what happened. Was that really meant to land perfectly vertically? It almost looks like it was upside down...but isn't. It's going to be truly amazing when they manage to do this.
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They have already managed to land vertically during short test flights on land, and yes, it does look amazing.

https://www.youtube.com/watch?v=xh9wCq-RJ8U
 
J

jett

D-Member
fallout said:
Given that they're trying to reuse the rocket for the purposes of saving money, I imagine they're hoping to keep the amount of consumables down to the bare minimum. It's entirely possible that they would have had enough under different conditions.

I also think that they're "ran out of fluid" explanation is probably a little light. There could be some logic errors or something that contributed as well.

It is a horrific crash. Basically, you either land it or you don't. I guess you could land it and it might tip over, but even then, that probably wouldn't be pretty.
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I guess there are all sorts of variables involved, no doubt.

Lucky Forward said:
^ lol



They have already managed to land vertically during short test flights on land, and yes, it does look amazing.

https://www.youtube.com/watch?v=xh9wCq-RJ8U
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Yeah but I mean within a "full" mission.
 
W

Wreav

Banned
AA is kind of a joke, aren't they? Haven't heard a peep out of them for any developments, no big contracts...I feel like it's more John living out his fantasy hobby than Elon, who is pushing the industry forward.
 
M

Mindlog

Member
Wow. It has to be, but considering what happened that barge is pretty tough.
Wreav said:
AA is kind of a joke, aren't they? Haven't heard a peep out of them for any developments, no big contracts...I feel like it's more John living out his fantasy hobby than Elon, who is pushing the industry forward.
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AA had a big accident and I believe they took a hiatus of some sort after that. They don't have the same capital other private firms do.
 
D

DBT85

Member
Cool that they released the video and seem to think that the extra hydraulic fluid will help for the next launch. Looking forward to it!
 
F

Flo_Evans

Member
DBT85 said:
Cool that they released the video and seem to think that the extra hydraulic fluid will help for the next launch. Looking forward to it!
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Maybe I'm not understanding how the fins work but why would you run out of hydraulic fluid?

Should be a closed system no?
 
J

jotun?

Member
Flo_Evans said:
Maybe I'm not understanding how the fins work but why would you run out of hydraulic fluid?

Should be a closed system no?
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Elon Musk @elonmusk · Jan 10
@alankerlin Hydraulics are usually closed, but that adds mass vs short acting open systems. F9 fins only work for 4 mins. We were ~10% off.
 
B

Bowdz

Member
fallout said:
I also think that they're "ran out of fluid" explanation is probably a little light. There could be some logic errors or something that contributed as well.
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The hydraulic fluid really does explain the entire scenario though. The grid fins were intended to guide the stage towards the barge right up to when the engine did the final burn. Elon said the grid fins ran out of fluid with 1 minute remaining until touchdown meaning there was an entire minute of this stage going 200mph before the final burn took place. It doesn't take a lot of imagination to think that it being in a free fall WITHOUT the control of the grid fins wouldn't place it pretty far off target.

The fact that the final burn tried to divert the stage to the barge (and the fact that it nearly did!) is insane. They are going to nail the landing on the 31st with DISCOVR.
 
D

DrForester

Kills Photobucket
fallout said:
I also think that their "ran out of fluid" explanation is probably a little light. There could be some logic errors or something that contributed as well.
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I don't know. They were very open about they were expecting a 50/50 chance of success, and were very outspoken that this was a first, and it could go wrong.
 
F

Flo_Evans

Member
jotun? said:
Elon Musk @elonmusk · Jan 10
@alankerlin Hydraulics are usually closed, but that adds mass vs short acting open systems. F9 fins only work for 4 mins. We were ~10% off.
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Interesting. I guess that is why I am flying rc drones and not launching rockets. :p
 
J

jotun?

Member
Flo_Evans said:
Interesting. I guess that is why I am flying rc drones and not launching rockets. :p
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A more complete explanation that someone posted on Ars Technica:

longhornchris04 said:
Its an open hydraulic system. Traditional, closed systems have a low pressure reservoir and use a pump to pressurize the fluid for the high-pressure portion of the circuit. After going through the actuator, the low pressure fluid returns to the reservoir.

In an open system, the reservoir stores fluid at high pressure - typically using an accumulator or a pressurized gas system. Usually there is a pressure regulator so the tank provides an even pressure until it is depleted. The fluid goes through the actuator (just like the open system) and then dumps into a low pressure environment - typically (but not always) a second catch reservoir so it doesn't go everywhere.

Open systems are nice and simple for short duration applications. They avoid the necessity of having a pump and power source - the tank itself has stored mechanical energy. On a rocket, this also avoids the mass penalties for having the pumps and power source, or alternatively the plumbing needed to get the hydraulic fluid to/from the only power source on the vehicle - the engine turbopumps. The system is lightweight and self contained, but like a battery has limited life.

Its probably worth noting that Merlin engines use a partial-open hydraulic system that is separate from the fin-control. The gimbal hydraulics get their hydraulic pressure from tapping off the fuel pump - since RP1 makes a good hydraulic fluid and avoids the need for a second hydraulic pump. After use as hydraulic fluid, the low pressure fuel is looped back into the system. Also, running out of fluid isn't really a concern... since there's no need to gimbal an engine that is out of fuel.
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Also: http://www.gfycat.com/ExemplaryBeneficialAmericanlobster
 
F

fallout

Member
Bowdz said:
The hydraulic fluid really does explain the entire scenario though. The grid fins were intended to guide the stage towards the barge right up to when the engine did the final burn. Elon said the grid fins ran out of fluid with 1 minute remaining until touchdown meaning there was an entire minute of this stage going 200mph before the final burn took place. It doesn't take a lot of imagination to think that it being in a free fall WITHOUT the control of the grid fins wouldn't place it pretty far off target.

The fact that the final burn tried to divert the stage to the barge (and the fact that it nearly did!) is insane. They are going to nail the landing on the 31st with DISCOVR.
Click to expand...

DrForester said:
I don't know. They were very open about they were expecting a 50/50 chance of success, and were very outspoken that this was a first, and it could go wrong.
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For sure. I just said "a little light". It's not like I was making it out to be some grand conspiracy. Just thinking that there may have been other issues at play that they haven't said anything about. I have no doubt that they'll have a better attempt next time with a very high likelihood of success given how close they were this time.

I think what they're doing here is remarkable. And they can certainly joke about it a bit because really, if they weren't doing this, that first stage would have been at the bottom of the ocean, anyway.
 
L

lednerg

Member
New challenges await SpaceX’s next rocket landing attempt
[...]
“We had some adjustments after the last fairly hard landing on CRS-5,” Koenigsmann told reporters Saturday, referring to the fiery touchdown Jan. 10. “We fixed the problems.”

The crash destroyed the rocket, but the booster’s guidance system and engines apparently functioned as designed, steering the 14-story stage to the football field-sized barge before it ran out of hydraulic fluid to drive four aerodynamic stabilization fins in the final moments of the Falcon 9’s vertical descent.

SpaceX chief executive Elon Musk said the new launcher for Sunday’s flight carries “way more” hydraulic fluid to remedy the problem. At least it should explode for a different reason, Musk quipped on Twitter.
[...]
The particulars of Sunday’s launch mean SpaceX has to forego one of the three braking burns employed on the Falcon 9’s usual descent profile. Instead of re-firing a subset of the first stage’s nine kerosene-fueled Merlin engines three times, there will be two ignitions on the way back to Earth on Sunday.

“There are a couple of differences in the trajectory,” Koenigsmann said. “We will perform an entry burn and a landing burn. The speed of the stage coming in to entry is actually higher, and that … makes it a little less likely to succeed.”

The initial “boost-back” burn designed to drive the rocket back toward Florida has been omitted for Sunday’s mission.

“We had an early burn originally,” Koenigsmann said. “That burn is what we can’t do this time because all the propellant goes to the primary mission.

Sunday’s launch is set for 6:10:12 p.m. EST (2310:12 GMT) from Cape Canaveral’s Complex 40 launch pad. The timing of the blastoff two minutes after sunset could put on a sky show for spectators for hundreds of miles across Florida.
[...]
Koenigsmann stuck with Musk’s prediction of a 50 percent chance of sticking the landing before the Jan. 10 launch.

“To me, we fixed one problem that we had last time,” Koenigsmann said. “There might be issues ahead of us. Obviously, this is a difficult thing, and at the same time, the trajectory is more difficult (for this launch).”

He said the booster will encounter twice the aerodynamic pressure experienced during the Jan. 10 flight.
[...]
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The live stream will begin today at 5:50PM EST.
 
blu

blu

Wants the largest console games publisher to avoid Nintendo's platforms.
I won't be able to stay up for the livestream, but I sincerely wish SpaceX best of luck with this cornerstone endeavor.
 
blu

blu

Wants the largest console games publisher to avoid Nintendo's platforms.
T-1h.. And I need to get up early tomorrow.. Why does sending a space rocket to Earth get me so excited?
 
M

maquiladora

Member
Was just reading about the history of the satellite being launched. Fascinating stuff. Originally proposed in the late 90's, it was due to be launched on the disastrous Columbia mission in 2003 but was put into storage and remained there for the duration of the Bush administration.
 
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