SpaceX Tuesday...

SpaceX Tuesday...

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Discussion

Eric Mc

114,733 posts

229 months

Tuesday 6th January 2015
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Not going today.

Eric Mc

114,733 posts

229 months

Tuesday 6th January 2015
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Looks like the gimballing system for the rocket motors did not function in line with the desired range of movements. The motors gimbal (swivel) to keep the rocket on course and stable during launch. The gimbal system on the 1st stage will also be crucial to keep the 1st stage pointing in the right direction when descending towards that barge.

Edit - turns out it was a problem with the second stage, not the first.

Edited by Eric Mc on Tuesday 6th January 11:34

scubadude

2,617 posts

161 months

Tuesday 6th January 2015
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Better safe than sorry- lets not forget the priority is the capsule going the the ISS the landing attempt is a reward if they loft NASA's stuff :-)

Whats the altitude, speed and downrange distance the 1st stage is trying to return from, I couldn't see it in SpaceX's blurb?


Eric Mc

114,733 posts

229 months

Tuesday 6th January 2015
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The recovery point is 200 miles offshore. It's quite a bit North East of Cape Canaveral and opposite the cost of Virginia. That's because the launch track is aiming for the orbital path of the ISS, which has a high inclination.

I think the 1st stage drops off at an altitude of about 30 miles but will continue on up in a parabolic arc until it starts descending again. It's also travelling supersonic for a good part of its fall.

MartG

17,631 posts

168 months

Tuesday 6th January 2015
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A couple of infographics




vescaegg

24,977 posts

131 months

Tuesday 6th January 2015
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MartG said:
A couple of infographics



This will be remarkable if it works.

MartG

17,631 posts

168 months

Tuesday 6th January 2015
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Well they've already managed to do every part of it bar the precision landing onto the barge - and they've been working on the landing part with their experimental Grasshopper rocket

Eric Mc

114,733 posts

229 months

Tuesday 6th January 2015
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It's joining the whole set of events into one smooth operation that is the hard part.

The SpaceX spokesman at the press conference last night was very entertaining.

When he was asked various questions along the lines of "What happens if.....", the answer was on every occasion - "We crash" - which he said with a smile.

The recovery process has to work 100% perfectly, or they will lose the booster.

Mojocvh

Original Poster:

16,837 posts

226 months

Tuesday 6th January 2015
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Oh bugger.

Simpo Two

74,922 posts

229 months

Tuesday 6th January 2015
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Hmmph, nothing between last post at 11.42GMT and 'spaceflight now' over a testcard. Didn't they put any cameras on the rocket?

Salgar

3,282 posts

148 months

Tuesday 6th January 2015
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Simpo Two said:
Hmmph, nothing between last post at 11.42GMT and 'spaceflight now' over a testcard. Didn't they put any cameras on the rocket?
I imagine they're not going to continuously broadcast until Friday?

Eric Mc

114,733 posts

229 months

Tuesday 6th January 2015
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There's not much to see to be honest.

The first thing they have to do is make sure that everything is "safed" i.e. all pyrotechnics and other armed devices are turned off and made safe.
Once that is all done, the next step is start detanking the fuel and oxidiser from the rocket. Most of this is done remotely because getting too close to a fully fueled rocket that was seconds ago primed to unleash 1.3 million lbs of thrust is not advisable.

As a result, there is nothing visibly happening in and around the rocket for a few hours. About the only evidence of action you see is the return of the "strong back" support to its pre-launch position and the gradual disappearance of the wisps of venting liquid oxygen as the tanks empty.

Simpo Two

74,922 posts

229 months

Tuesday 6th January 2015
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Thanks Eric. I stupidly assumed that a caption saying 'spaceflight now' meant that it was in spaceflight now, ie launched. If they don't want to keep a live feed then 'still on launchpad, come back Friday' might have been better!

Eric Mc

114,733 posts

229 months

Tuesday 6th January 2015
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I think you might be interpreting their site name a bit too literally.

Maybe they should a number of sub-sites called -

Spaceflight Then
Spaceflight Now
Spaceflight Next

and perhaps

Spaceflight Maybe But Not Likely

That should cover all bases.

MartG

17,631 posts

168 months

Tuesday 6th January 2015
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Eric Mc said:
I think you might be interpreting their site name a bit too literally.

Maybe they should a number of sub-sites called -

Spaceflight Then
Spaceflight Now
Spaceflight Next

and perhaps

Spaceflight Maybe But Not Likely

That should cover all bases.
rofl

Simpo Two

74,922 posts

229 months

Tuesday 6th January 2015
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Eric Mc said:
I think you might be interpreting their site name a bit too literally.

Maybe they should a number of sub-sites called -

Spaceflight Then
Spaceflight Now
Spaceflight Next

and perhaps

Spaceflight Maybe But Not Likely

That should cover all bases.
Oh yeah, I just realised that's the name of the site...

Well it's a jolly silly name for a site that doesn't always cover something flying in space. Bah.

Not that you can really 'fly' in space anyway, you just get punted along by exhaust gas.

'Exhaust Gassing Maybe But Not Likely' dot com. There you go, nice and accurate smile

SpeedyDave

417 posts

190 months

Wednesday 7th January 2015
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Eric Mc said:
What is the problem with gentle plop into the ocean?

I am sure they could get the accuracy to within a couple of hundred yards of a recovery vessel. If the vessel had a bespoke lifting device on it, they could have it out of the water in less than an hour.

I expect they are probably concerned about the issue of the effect of salt water on the rocket motors - and to be honest - that was the main reason why NASA

a) gave up on the idea of recovering the 1st stages of Saturn IBs and Saturn Vs

b) chose Solid Rockets for the Shuttle programme
Musk has said many times a core objective of SpaceX is to develop the tech to get to & from Mars, the Moon, etc. There is no water to plop down on if you're going anywhere other than Earth so accurate propulsive landing is essential.

I also suspect that when you're talking about a sophisticated object taller than a 12 story building no 'plop' is gentle enough. This isn't a simple solid fuel canister, its high pressure liquid fuel storage plus the engines and all the supporting systems.

Perhaps it could be done at the cost of ??? added weight for strengthening etc but even if successful its still a long long way from the complete & rapid reuse goal. I can't imagine flying it again without a lot of work to check, clean, refurb, & probably replace a *lot* of the bits.

Their goal is to be able do not much more than just refuel & then fly again.

From what we've seen so far I really think they're going to get there. SpaceX is already massively undercutting the cost of other systems, imagine when they start recovering the 70% vehicle cost that the first stage represents.

Total game changer.


Eric Mc

114,733 posts

229 months

Wednesday 7th January 2015
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I agree.

As mentioned, soft landing using braking rockets on the moon and Mars has been done quite a few times. The problem is that it hasn't been done with a tall thin object on earth before and I think the dynamics are quite different.

However, I think they will get there in the end and I am looking forward to Friday.

SpeedyDave

417 posts

190 months

Wednesday 7th January 2015
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MartG said:
A couple of infographics



The graphic gives the impression the legs are deployed quite late and essentially just for the touchdown. Actually they're an important part of the aero braking solution and cut the terminal velocity of the falling vehicle in half.

Anyone know what altitude they deploy?

MartG

17,631 posts

168 months

Wednesday 7th January 2015
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"SpaceX has chosen Saturday, Jan. 10 to launch its next commercial resupply services mission to the International Space Station. Launch of the Falcon 9 rocket and Dragon spacecraft is targeted for 4:47 a.m. EST from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. The previous launch attempt on Tuesday was halted with one minute, 21 seconds left on the countdown clock. Engineers observed drift on one of two thrust vector control actuators for the Falcon 9’s second stage and stopped the countdown.
For a launch on Saturday, NASA Television coverage will begin at 3:30 a.m. A Saturday launch will result in the Dragon spacecraft arriving at the space station on Monday, Jan. 12."