will Space X land rocket cells today?

Will Space X land rocket cells today?

  • Yes, landing will be textbook!

    Votes: 4 25.0%

  • No, landing will be a loss

    Votes: 5 31.3%

  • weather will scrub the launch again today

    Votes: 7 43.8%
  • Total voters
    16
  • Poll closed .
Jim Logajan said:
They tried it that way. Didn't work.

Extracted the following from this article from 2001:
http://www.newscientist.com/blogs/shortsharpscience/2011/09/falcon-rockets-to-land-on-thei.html
"SpaceX's original concept for first-stage recovery and reuse didn't work and apparently is being abandoned. The original concept seemed simple: the spent first stage would parachute down to a splashdown offshore, where it would be recovered by boat and hauled back to shore for refurbishment and reuse. There were some obvious questions about how well a rocket stage would survive being soaked in seawater, which is quite corrosive; perhaps only selected components would be reusable, not the whole stage. (Yes, NASA recovered the shuttle SRBs the same way, but their refurbishment process was so labour-intensive that it's not clear it ever really saved them any money.)
Overall, the idea seemed like a clumsy makeshift, and some doubted that there would be much real benefit, but it didn't seem ridiculous – just challenging.
The only problem was, it didn't work. At the Space Access conference in April, Gwynne Shotwell, SpaceX's president, admitted: "We have recovered pieces of the first stages." The first stages weren't even getting as far as deploying their parachutes – they were breaking up during atmospheric re-entry.
So it was back to the drawing board for SpaceX. And the new plan actually seems much more promising. After the upper stages separate from it, the nearly-empty first stage will reignite some of its engines to turn around and come back to its launch site, and will then land vertically on rocket power, like the experimental DC-X and the private rockets competing in NASA's Lunar Lander Challenge. In due time, SpaceX aims to have the second stage also re-enter behind a heat shield on its nose, and do the same vertical rocket landing."

​
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Hmmmmm...

If they propose a vertical landing and they are hell bent on pushing that theory then they will discredit any other option...:rolleyes::rolleyes:..

So... if the first stage was breaking up during re entry with the chutes... How in the hell are they gonna bring it back under power..:dunno::dunno::dunno::confused:....:confused:
 
For those who don't want to click the Vine:

DyOjqkt.gif
 
Clark1961 said:
can you imagine coordinating two moving powered targets....not a pretty thing

I believe some folks got pretty good a snatching targets descending under parachute but trying to catch a descending rocket would be just a tad different.
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Happens all the time in deep water offshore operations, the rig is DPing off the satellite and the boat is fine tune laser DPing the rig. One time Schlumberger sent out new coveralls to their rig hands with those super cool reflective arm bands sewn on. I've got a diver with a riser over the side working within 2M of this rig, and all of a sudden the the boat starts driving forward. I looked out, as I was taking it back and saw the laser had captured a guy's armband and was following him.:eek: All the new coveralls got modified after that.:lol:

I don't think it could "catch the rocket" but it could increase the landing parameter with the same type of technology we use in heave suppression on dynamic crane lifts, only in the horizontal rather than vertical planes. Probably need big jet pumps for that type of reaction level/speed though.
 
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Henning said:
Happens all the time in deep water offshore operations, the rig is DPing off the satellite and the boat is fine tune laser DPing the rig. One time Schlumberger sent out new coveralls to their rig hands with those super cool reflective arm bands sewn on. I've got a diver with a riser over the side working within 2M of this rig, and all of a sudden the the boat starts driving forward. I looked out, as I was taking it back and saw the laser had captured a guy's armband and was following him.:eek: All the new coveralls got modified after that.:lol:

I don't think it could "catch the rocket" but it could increase the landing parameter with the same type of technology we use in heave suppression on dynamic crane lifts, only in the horizontal rather than vertical planes. Probably need big jet pumps for that type of reaction level/speed though.
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Somebody misunderstands here. I'm sure Read The Instructions was DPing to a very small radius. It's pretty common and doesn't take a laser. We were doing it with sat and pinger data in 91/92 timeframe.

What I thought you were suggesting was trying to "catch" the rocket with the barge and that is pretty much a non-starter because of the horsepower required and mass of the system without even considering the control of two powered objects.
 
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There are three primary ways to locate with DP, Satelite, laser, or taught wire to the bottom; radar location systems are also available, but I have never seen them outside training. DP is often used to hold a small location yes, but is not really restricted to that roll. There are multiple modes that the system can be used to run autonomous search patterns or any other control manipulations. What it will allow the vessel to do depends on how much power is involved. It is Dynamic Positioning after all, not Fixed Positioning. It can deal with whatever.
 
Henning said:
There are three primary ways to locate with DP, Satelite, laser, or taught wire to the bottom; radar location systems are also available, but I have never seen them outside training. DP is often used to hold a small location yes, but is not really restricted to that roll. There are multiple modes that the system can be used to run autonomous search patterns or any other control manipulations. What it will allow the vessel to do depends on how much power is involved. It is Dynamic Positioning after all, not Fixed Positioning. It can deal with whatever.
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Taught wire lasted about 10 minutes in service. Sonic systems had a long run prior to GPS. The short baseline systems used hydrophones on the ends of the vessel and a pinger on the stack for target location. Long baseline systems used a single hydrophone location on the vessel and an array of pingers on the seafloor around the vessel. Now GPS makes it cheap and easy to fix location. Satellite was just coming on the stage in the early 90's. Now GPS is the way to go but I'm no longer involved in that stuff.

All that said, you're not going to drive a barge under a rocket.

Watch the video. SpaceX's control is way out of whack, they're over-controlling which tells me their dynamic model needs work, lot's of work.
 
Clark1961 said:
they're over-controlling which tells me their dynamic model needs work, lot's of work.
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Really? Tell us more. :rolleyes:
You're certain, based on your in-depth analysis that it couldn't have been a fairly simple nonlinearity in the system that shouldn't have been there?

Nauga,
who is both robust and adaptive ;)
 
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nauga said:
Really? Tell us more. :rolleyes:

Nauga,
who is both robust and adaptive ;)
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So you believe their model is robust and adaptive? or do you just want to shoot at me because we've had a disagreement?
 
Clark1961 said:
So you believe their model is robust and adaptive? or do you just want to shoot at me because we've had a disagreement?
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It would be their controls that would be robust and adaptive, not their model, and I'm not at liberty to say but given what Musk says was the cause the answer should be apparent. I'm "shoot[ing] at [you]" because I don't think you have a clue as to the root cause but want to sound like you do.

What disagreement have we had?

Nauga,
and his peer reviewers
 
Clark1961 said:
So you believe their model is robust and adaptive? or do you just want to shoot at me because we've had a disagreement?
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I believe the system is robust and adaptive, and properly applied may make the difference in being able to land it reliably or not. I think with some 'thinking outside the box' they can dramatically increase the error tolerance by using the barge to counter lateral energy.
 
nauga said:
It would be their controls that would be robust and adaptive, not their model, and I'm not at liberty to say but given what Musk says was the cause the answer should be apparent. I'm "shoot[ing] at [you]" because I don't think you have a clue as to the root cause but want to sound like you do.

What disagreement have we had?

Nauga,
and his peer reviewers
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It is obvious that their controls weren't up to the task. If you don't recognize an overshoot, well, I can't help you there. Do I know exactly where the problem is? no but it's quite clear they haven't solved the problem and had some wild excursions near the barge. That's enough to tell me that their control model is wrong.

On another note, I'm happy to disagree with people. I'm a little unhappy when the other party refuses to be a gentleperson about it and wants to denigrate. I don't assume anyone is correct simply because they say so and this is just another case in point "Oh, I'm a peer reviewer and I know" doesn't do much for me since I am a reviewer in my profession too. What people claim in papers and what people can prove are nearly always two very different things.
 
Henning said:
I believe the system is robust and adaptive, and properly applied may make the difference in being able to land it reliably or not. I think with some 'thinking outside the box' they can dramatically increase the error tolerance by using the barge to counter lateral energy.
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Lateral energy wasn't the problem, the rocket over-corrected twice and didn't quite get back to vertical before impact. My initial reaction is that the control system needs some work. Thinking outside the box is nice and all but changing from one maneuvering system to two maneuvering systems is just going to make control more difficult. Maybe they need better wind profiling or something along those lines but giving the rocket a moving target would be a bad idea IMNSHO.
 
Clark1961 said:
Lateral energy wasn't the problem, the rocket over-corrected twice and didn't quite get back to vertical before impact. My initial reaction is that the control system needs some work. Thinking outside the box is nice and all but changing from one maneuvering system to two maneuvering systems is just going to make control more difficult. Maybe they need better wind profiling or something along those lines but giving the rocket a moving target would be a bad idea IMNSHO.
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That's just it, the corrections can be reduced by the barge. I'm just saying there are aspects of DP that can be combined into the program that can produce an advantage.
 
Henning said:
That's just it, the corrections can be reduced by the barge. I'm just saying there are aspects of DP that can be combined into the program that can produce an advantage.
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But the rocket and the barge are going to have to be datalinked without lag. Sorta tough with a plume of hot gas under the rocket. In other words, really bad idea.
 
N801BH said:
I commend SpaceX for their noble attempt at vertical landings...

BUT....

They need to follow the business model of the Thiokol SRB's from the shuttle....
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If you divide the old cost of the space shuttle program annually by # of launches per year I don't think the cost was ever less than $400 million per launch, and usually it was higher.

That appears to be a failed business model if the goal is to reduce cost.
 
Datadriver said:
If you divide the old cost of the space shuttle program annually by # of launches per year I don't think the cost was ever less than $400 million per launch, and usually it was higher.

That appears to be a failed business model if the goal is to reduce cost.
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My point was the refurb costs to the SRB's alone.... Not the entire shuttle turnaround costs...
 
N801BH said:
My point was the refurb costs to the SRB's alone.... Not the entire shuttle turnaround costs...
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As was mentioned, they are wholly different units, you just gave the reason why, they were SRBs, this is a liquid fuel rocket. One is bottle rocket, the other is Lamborghini inside a bottle rocket. Lamborghinis don't respond well to going under water either.:nono:
 
Henning said:
That's not new, that technique dates back to the early days of high atmosphere and space research. Then there was the rig to snatch people tethered to a balloon off the ground with an airplane.:eek:
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I'm familiar with the Fulton recovery system but jeez, that thing is a bit heavy even empty on fuel
 
Henning said:
As was mentioned, they are wholly different units, you just gave the reason why, they were SRBs, this is a liquid fuel rocket. One is bottle rocket, the other is Lamborghini inside a bottle rocket. Lamborghinis don't respond well to going under water either.:nono:
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99% of the space inside the liquid fueled rocket is for fuel storage.... The rest is steerage and comm stuff.... They are easily refurbed......

I guess the question is... Are they trying to save /salvage the entire 1st stage rocket body so they can use it again...:dunno::confused::confused::confused:
 
N801BH said:
99% of the space inside the liquid fueled rocket is for fuel storage.... The rest is steerage and comm stuff.... They are easily refurbed......

I guess the question is... Are they trying to save /salvage the entire 1st stage rocket body so they can use it again...:dunno::confused::confused::confused:
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Obviously that is the intent. The motors and pumps are expensive, high precision units under extreme conditions. If they can spare them going under water they are much better off, then there is cleaning the salt out of everything....
 
Henning said:
Obviously that is the intent. The motors and pumps are expensive, high precision units under extreme conditions. If they can spare them going under water they are much better off, then there is cleaning the salt out of everything....
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Geez Henning..... What do you think they will do for a turnaround if it stays out of the water.. just refill and relight ??:dunno::dunno:...

Or dissemble, repair /replace so it works perfect again ?
 
N801BH said:
Geez Henning..... What do you think they will do for a turnaround if it stays out of the water.. just refill and relight ??:dunno::dunno:...

Or dissemble, repair /replace so it works perfect again ?
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They don't have to deal with the consequences of being salt water soaked. It adds a huge level of PITA to the refurb.
 
I wonder how many FPM that rocket is approaching the barge at? It looks really fast from the rough video I saw. Slower would give more time for the adjustment controls to be effective/stabilize?
 
Oh, and by the way. The paying customer is almost certainly going to get his packages delivered on time.

I'm sure the Italian astronaut will be happy to take his new espresso machine out of the box with the smile on it.
 
N801BH said:
Geez Henning..... What do you think they will do for a turnaround if it stays out of the water.. just refill and relight ??:dunno::dunno:...

Or dissemble, repair /replace so it works perfect again ?
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I have heard that SpaceX engineers believe that they can launch a second rocket with the same first stage back to back, then refurbish afterwards.
 
N801BH said:
99% of the space inside the liquid fueled rocket is for fuel storage.... The rest is steerage and comm stuff.... They are easily refurbed......

I guess the question is... Are they trying to save /salvage the entire 1st stage rocket body so they can use it again...:dunno::confused::confused::confused:
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Well... the only really valuable bit is the motor itself. Fuel tankage (the 99% of the volume) and the electronics are easily and cheaply replaceable. But a big liquid-fueled motor is a complex and fiddly bit of hardware. As Hemming has said, they don't take kindly to salt water.

The Space Shuttle main engines and Orbital Maneuvering engines were returned and re-used... after refurbishment and a test-stand run.

So, obviously, the main goal is to recover the engines for re-use rather than the big empty tube and a glorified PC. Shuttle engines weighed a bit less than four tons each. Falcon engines weigh about 1400 pounds, but there *are* nine of them in the first stage.

The US did used to recover stuff via airplane, but the stuff was coming down on a parachute. So the "power pack" would need to be jettisonable from the main body and deploy its own parachute(s). Storing that 'chute a few feet from a rocket engine should be an interesting problem.

Ron Wanttaja
 
Badger said:
I wonder how many FPM that rocket is approaching the barge at? It looks really fast from the rough video I saw. Slower would give more time for the adjustment controls to be effective/stabilize?
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It would also require more fuel, which is more weight which is more inertia... The most efficient way is with a timed max thrust burst that ends the deceleration on touch down. Anything other than that adds more complications than it reduces.
 
JimNtexas said:
Just Read The Instructions uses the Thrustmaster Dynamic Positioning System. There are unconfirmed reports that SpaceX installed larger thrusters for this week's launch after the sea state issues they had which canceled the last scheduled landing attempt.
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The issue is the thrust vectoring....and the amount of authority they provide for making a stable landing. This was an issue for the Delta clipper DC-X....and that was landing on stable ground, not a moving target.

I suspect they'll drop back and punt after a few more failed attempts.
 
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