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 Posted:   Jan 10, 2015 - 3:27 PM   
 By:   Grecchus   (Member)

I'm a little surprised the subject of the SpaceX project which plans to launch AND land the main body of a payload carrier so as to render it re-useable does not seem to have garnered much interest on the board. This is nothing less than a kind of breakthrough in rocket design, manufacture and conceivably - maintenance.

I have to admit the idea of a made in Hollywood, Flash Gordon, Destination Moon styled actual rocketship breaks free with what has been my former notions of what the capabilities of a launch vehicle should be. The SpaceX concept of efficiency leaves the whole of launch vehicle history well and truly behind.

Yesterday's launch went as planned but there was an attempt to bring back the vehicle, not only intact, but for it to make a controlled landing on a platform at sea! Is this a hoax or has SpaceX come close to solving what seems to me to be an impossible problem?

http://www.bbc.co.uk/news/science-environment-30752515

 
 Posted:   Jan 10, 2015 - 4:03 PM   
 By:   solium   (Member)

I follow NASA a lot more than the private companies. So I'm not in the know with all they are doing.

I found this interesting:

Didn't get good landing/impact video. Pitch dark and foggy. Will piece it together from telemetry and... actual pieces.

So they spend hundreds of millions on this, but don't have footage of the parts of the test that failed? Yeah right!

This is why I'm leery of moving science exploration into the private market. It's gonna be PR BS.

 
 Posted:   Jan 10, 2015 - 4:18 PM   
 By:   Grecchus   (Member)

So we're more or less thinking along the same lines, Sol. The thing I don't understand is they have a perfectly workable launch and orbital delivery configuration. They've made the grade. What possible use is there in generating controversy over something like this, unless it's a smokescreen to trounce competitors?

If they really have got a design that takes the first stage to an altitude from where it can be recovered, improbable though it may seem, then they've cracked an operational research problem that will be a game-changer. Of course, the solution is one in which the staging altitude is not too high for the first stage and not too low for the second.

 
 Posted:   Jan 10, 2015 - 4:40 PM   
 By:   solium   (Member)

I'm not saying it won't work and perhaps they will crack the nut and develop the technology for such a system. But two things to remember. NASA does science for the public, SpaceX does science for the CEO's and stockholders of said corporation.

Also what most ppl don't realize is they don't go to the bank and take out a loan to develop their system. They get multi millions in tax payer dollars. They have a vested interested in bragging about the successes, and hiding the failures.

 
 Posted:   Jan 13, 2015 - 5:06 PM   
 By:   Grecchus   (Member)

Update:

http://www.bbc.co.uk/news/science-environment-30779781

 
 Posted:   Jan 14, 2015 - 7:03 AM   
 By:   solium   (Member)

I'm not quite sure why they tried to land on a floating platform in the middle of the ocean. (in the dark no less) Unless they wanted to hide a potential failure.

 
 Posted:   Jan 14, 2015 - 10:55 AM   
 By:   Grecchus   (Member)

The most important thing was to re-supply the crew on the ISS. It seems the american module has had an ammonia leak. It's like the old age problems of Mir are now besetting the ISS. Hope they resolve the problem asap.

The launch had been postponed. At the time I was half-listening in and the American controller was suggesting the sensors were accounting for some kind of drift while the launch vehicle was stationary on the pad. They'd planted the idea something was wrong with the stabilizer gyros on the rocket's instrumentation because it was audible and not too hard to relate.

Then, when the launch finally goes ahead it's in the dark. The gyros don't seem to have had a problem getting the payload into orbit, at least from the 2nd stage instrumentation sensory apparatus. The problem was with the 1st stage section which spread it's legs, then plonked itself down hard on the crosshairs (we are told) a considerable distance off the coast of Florida. The implication is it would have worked but for some measly hydraulic fluid needed to manipulate the aerofoils for controlled flight, located somewhere on the landing stage.

What I find extraordinary is that the space shuttle's SRBs were always recovered after parachutes were deployed to soft-land them into the sea. Why on earth can't SpaceX use that tried and tested method? You see, when a launcher lifts off, it's under constant, never-ending acceleration until it meets its target altitude either in the atmosphere or in orbit. That's one of the physical principles that allowed the extremely complex Saturn V rocket to keep together on it's way up. All the joins between stages were being compressed together due to the acceleration. The point being they are designed to go faster and faster, not slower and slower. The only instance I can think of when a vehicle used rocket engines to land was when the LEM met with moondust in zero atmosphere. That is to say with no wind currents to buffet it all the way down.

The problems of trying to keep a long cylindrical mass upright most of the way down within the atmosphere imply that a considerable fuel reserve is required to decelerate and cushion the landing. We've all seen failed rocket launches where they've exploded on the pad - it's a difficult proposition at best for a long limbed rocket to maintain stability at slow speed close to the ground. But as I've pointed out, launch vehicles aren't called "rockets" for nothing. Sure, I'm no rocket scientist, but I've been following the technology as it's been developed over decades and the idea of landing an oversize missile with pinpoint accuracy on it's arse seems just a little bit strange.

Don’t get me wrong. I'm really enthusiastic about any practical method being perfected to re-use hardware, it's just that my sense of the possible is sorely tested by the technique SpaceX is touting as it's claim to fame. I've always thought that each launch requires a new build. The trick is to employ the simplest tried, tested and proven assembly line there is. And I truly believe that is as cheap as it can get (this obviously applies to the 2nd stage, which needs renewal for all launches.)

 
 Posted:   Jan 14, 2015 - 11:45 AM   
 By:   solium   (Member)

Well I think you sound like a rocket scientist! wink Maybe they are letting their imagination get the best of themselves and can't escape the nostalgia of Buck Rogers science. (fiction)

As you said not only does it have to work, it has to be practical. The amount of fuel needed for re-entry, the stress on motors, etc. Also it's easier to shoot a cylinder straight up into the air and maintain it's vertical alignment. It's not an aerodynamically sound design for going in reverse. Heck even the Space Shuttle glided back to Earth! The idea of recovery, like the SRB's makes a lot of sense. Though I suppose you can greatly cut down on recovery costs if the thing can soft-land anywhere you want it too.

I still don't get why they are doing it out at sea. Unless they fear the rocket could vear way off target (into a populated area) for a Cape Kennedy landing. But hey, the Shuttles glided across the entire length of the country from West to East, made a slight U-Turn and then landed on a ground based runway.

 
 Posted:   Jan 14, 2015 - 11:55 AM   
 By:   Grecchus   (Member)

I still don't get why they are doing it out at sea. Unless they fear the rocket could vear way off target (into a populated area) for a Cape Kennedy landing. But hey, the Shuttles glided across the entire length of the country from West to East, made a slight U-Turn and then landed on a ground based runway.

Yes, it has to be safety first. There must be a fair bit riding on this method of recovery - reputation probably being the single most important factor. As you say, Sol, a private company has been handed considerable responsibility for providing a launch service as and when required. The SpaceX vehicle is meant only for delivering payloads to low earth orbit, meaning ISS - a milk run. If they can simplify the process with a major component that is re-usable, they will then be able to say it took the foresight of the private sector to do it and a pat on the back would have been well-earned for the ingenuity and resolve to get the job done. When I see it done, then I'll hoot and clap with the rest (as long as the fat lady DOESN'T sink.) wink

This helps show the principles behind the Falcon 9 rocketship:

http://www.space.com/28167-spacex-risky-reusable-rocket-landing-infographic.html

http://www.spacelaunchreport.com/falcon9.html

 
 Posted:   Jan 17, 2015 - 5:57 AM   
 By:   Grecchus   (Member)

It does look like the landing came close.

http://www.bbc.co.uk/news/science-environment-30860258

I'd really like to see the 1st stage hit the deck, although not quite so hard or fast next time round. I'm not going to wish them luck for next time, because luck should have nothing to do with it. The hardware either has the capability, or it doesn't.

 
 Posted:   Jan 17, 2015 - 8:43 AM   
 By:   solium   (Member)

That was a spectacularly cool failure! Surprised they released this footage after all.

 
 Posted:   Jan 17, 2015 - 9:25 AM   
 By:   Grecchus   (Member)

I think it's because the 1st stage found it's way to mama, even if it head-butted the front door.

Why didn't I think of this before! The excellent Orbiter space flight simulator I mentioned some time ago has a user interface that allows talented users to build their own spacecraft as well as the virtual systems that would work the same way in real life.

So here is a YouTube reconstruction someone has helpfully downloaded of what the Falcon 9 is meant to be capable of - sometime in the near future:

https://www.youtube.com/watch?v=4Xdij_9t0z8

Having been trawling through YouTube, I came across this wonderful exchange between Elon Musk and Newsnight:

https://www.youtube.com/watch?v=K-uLAFb7GOg

 
 Posted:   Jan 17, 2015 - 10:39 AM   
 By:   solium   (Member)

That's pretty cool! I still want to see things glide back to Earth on wheels. Rocket power decent seems so archaic. But if it works and really cuts down costs you can't argue the technology.

 
 Posted:   Feb 2, 2015 - 3:05 PM   
 By:   Grecchus   (Member)

Straight from the horses mouth, although it's always great on paper:

http://www.dailymail.co.uk/sciencetech/article-2929743/The-world-s-powerful-rocket-SpaceX-animation-shows-Falcon-Heavy-lift-one-day-send-humans-Mars.html

There's also this article which is interesting from an orbital mechanics pov:

http://www.dailymail.co.uk/sciencetech/article-2931725/ISS-moves-closer-home-Space-station-lowers-orbit-make-commute-Earth-space-shorter.html

 
 Posted:   Feb 3, 2015 - 7:13 AM   
 By:   solium   (Member)

Straight from the horses mouth, although it's always great on paper:

There's also this article which is interesting from an orbital mechanics pov:


Two great articles!

I can't believe they spun the space station around and then lowered its orbit! Wozsers!

As far as reusable rockets. Will be cool if it works. I would like to see cost analysis. Fuel is usually one of the most expensive parts of launching rockets and here you need enough fuel for launch and landing. I would also like to know the stress of the engine parts and motors doing double duty.

 
 Posted:   Feb 3, 2015 - 1:02 PM   
 By:   Grecchus   (Member)

They can always raise the ISS orbit when that suits. What doesn't make sense is that the russian Progress is a tried and tested vehicle. Maybe if the ISS orbit is a little less eccentric then rendezvous is less tricky? Playing catch-up in orbit is an interesting 'game.' The higher you are, the less orbital velocity is required. The lower you are, the faster you will go - these are the laws of physics at play. Rendezvous is dependant on precise thruster vectoring at the point of closest contact, and has to be continuous until station keeping means the vehicle is "merged" with the station. Hohman transfers are usually good enough to do the job.

Actually, now that I'm in the groove, going back to Apollo, the most interesting part of the entire experience (for me) was blasting off from the base of the lander whilst on the moon (using it as a launch platform), followed by the ascent to the point at which the LM's upper stage turned off it's single rocket engine, which couldn't be throttled or reignited once turned off. It was either full "on" or "off." That rocket engine and the vernier thrusters were the only "tether" the two guys had to the CM - and hence, to life itself. Now, if you really think about it, that is freaking incredible. That rendezvous is out of this world in the conception and the execution! My admiration for the 12 men who performed that feat is unlimited. Without doubt the single most incredible accomplishment of flight and navigation ever to be performed by man. Of course, the entire journey is one monumental feat of scientific precision. Though when you break it down into the various segments, that ascent takes the biscuit. Now, you might think the landing itself is the greater feat (especially 15's mountian hugging all the way down to Hadley Rille,) but that dash for an intitial parking slot between the moon and the CM is tops for me!

As for SpaceX, I think the Falcon 9 is expected to be reliable for at least 40 launches. In the animation from SpaceX, the rocket engine bells are bearing the brunt of heating on reaching denser air, so they must be very strong to absorb so much "punishment." Some components will be prone to differences in mtbf and will need replacement according to inspection, I should think.

 
 Posted:   Apr 14, 2015 - 2:04 PM   
 By:   Grecchus   (Member)

A ringside seat has been provided for the next attempt, which is imminent.

http://www.space.com/17933-nasa-television-webcasts-live-space-tv.html

Will SpaceX bag a first - care to place your bets?

 
 Posted:   Apr 14, 2015 - 2:57 PM   
 By:   solium   (Member)

A ringside seat has been provided for the next attempt, which is imminent.

http://www.space.com/17933-nasa-television-webcasts-live-space-tv.html

Will SpaceX bag a first - care to place your bets?


I saw the launch. But it didn't successfully land. Maybe thirds time the charm?

 
 Posted:   Apr 14, 2015 - 3:12 PM   
 By:   Grecchus   (Member)

That's a shame. Did the stage get anywhere near again, or was it wide of the mark?

Edit: I've just read it hit hard again and maybe tipped over. They need to rethink something. Maybe the rocket engines need to hover the stage before touchdown while the barge is about to roll through the horizonal. The barge platform surface needs to talk to the stage guidance software - a sort of "meatball" for vertical landings. Of course, they must have already considered this important point, but, maybe they need to "soften" the edges.

 
 Posted:   Apr 14, 2015 - 3:32 PM   
 By:   solium   (Member)

That's a shame. Did the stage get anywhere near again, or was it wide of the mark?

My understanding from a still pic (didn't see the landing live) it got close to soft landing on the platform then tipped over on the platform.

 
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