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from the recycling-is-good-for-the-planet dept.
http://arstechnica.com/science/2017/01/spacex-may-be-about-to-launch-its-final-expendable-rocket/
After successfully returning to flight on January 14, SpaceX will make its next launch from Cape Canaveral no earlier than January 30. With this mission from a new pad at Launch Complex 39A, SpaceX will loft the EchoStar 23 communications satellite to geostationary transfer orbit. This is a heavy satellite, weighing 5.5 metric tons, and getting it out to about 40,000 kilometers from the surface of the Earth will require pretty much all of the lift capacity of SpaceX's Falcon 9 rocket. This would leave almost no propellant for the Falcon 9 rocket to fire its engines to slow down, make a controlled descent through the Earth's atmosphere, and attempt a difficult landing on a drone ship.
On Saturday, in response to a question on Twitter, SpaceX founder and chief executive Elon Musk confirmed that the upcoming EchoStar launch will therefore indeed be expendable. "Future flights will go on Falcon Heavy or the upgraded Falcon 9," he added. In other words, in the future such heavy payloads will either be launched on the more powerful Falcon Heavy (consisting of three Falcon 9 cores, designed for return), or a slightly more powerful variant of the Falcon 9 rocket. Although SpaceX may launch one or two more expendable rockets, Musk is saying the plan here onward is to try and launch everything on reusable boosters.
(Score: 2) by VLM on Monday January 23 2017, @04:51PM
This would leave almost no propellant for the Falcon 9 rocket to fire its engines to slow down, make a controlled descent through the Earth's atmosphere, and attempt a difficult landing on a drone ship.
They should try it anyway, aiming for land or very shallow water, not the ship. Maybe shallow water would be ideal, although the waves from impact might be a problem.
Its hard to get specs on how much the first stage weighs. Lets say the overall rocket is a million pounds which is pretty close. Of which maybe the first stage is half that, and at least 90% of that is fuel, so a first stage weighs 50 kilopounds to one or fewer sig figs. Scrap aluminum maybe 50 cents per pound. That's $25K. Now if it holed and sunk the barge, that would not be economically profitable, but if it decelerated enough to be bulldozeable someone would spend less than $25K to haul the bits to a scrapyard, get $25K from the yard, net result a small profit for someone, just for loading code that makes it hit a landmass instead of the ocean, even if its not reusable in the aerospace sense it is reusable in the recycling sense.
As an alternative solution what about a shallow water landing for fish habitat and cave diving training? I mean given a choice of deep water impact where it'll help no marine creatures or shallow water where it can provide nesting habitat for fish, may as well burn the last couple kilograms of propellant for a good purpose.
(Score: 0) by Anonymous Coward on Monday January 23 2017, @05:01PM
I'm pretty sure that rockets are not things that fish enjoy. They contain toxic fuels (hydrazine maybe?) and materials. Marlin and Dory will not enjoy the rocket's initial impact and the burning sensations that accompany its re-entry, nor will survivors from nearby maritime habitats enjoy the toxic waste wafting through the sea, nor will generations of fish make Mr. Rocket a happy place for singing about the glorious contributions to the environment made by the mysterious humans who sent Mr. Rocket crashing down from heaven into the shallows.
(Score: 3, Touché) by takyon on Monday January 23 2017, @06:09PM
So if they don't try to land it intact, where does it go? Heaven?
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1) by khallow on Monday January 23 2017, @06:55PM
(Score: 3, Informative) by khallow on Monday January 23 2017, @06:37PM
They contain toxic fuels (hydrazine maybe?) and materials.
Traces of kerosene and probably some sort of lubricates are probably the extent of the toxic materials. SpaceX routinely launches payloads with hydrazine fuel, but first stage fuel is LOX and kerosene. I think a bigger problem is that most of the remaining mass of the rocket is fairly reactive metal. Not so much that it'll be toxic, but that it'll corrode a lot faster than steel will in contact with sea water.
(Score: 2) by frojack on Monday January 23 2017, @07:28PM
ut that it'll corrode a lot faster than steel will in contact with sea water.
Exactly.
Although its not instantaneous, and one dunking won't kill the metal, salt warer is definitely hard on some aviation metals. That being said, there are a lot of aircraft that are exposed to salt water all the time (float planes, anfibs, etc) without significant degradation from exposure. One has to assume the particular formulation of the aluminum is specifically chosen for this.
But the other consideration of water exposure is that is the electronics and wiring need not be water proof just to fly in space. Water would seep into all sorts of wire terminations and components.
Also, water is not the softest landing surface, and splashdown would not be delicate.
No, you are mistaken. I've always had this sig.
(Score: 1) by khallow on Monday January 23 2017, @07:39PM
Also, water is not the softest landing surface, and splashdown would not be delicate.
Even air is not a soft enough landing surface, if you hit it hard enough at a steep enough angle.
(Score: 2) by bob_super on Monday January 23 2017, @08:00PM
Angle is actually the key: Rockets are designed to take some really impressive loads longitudinally.
If you're gonna splash one, and it has the SpaceX fins (even without propellant, or just the tiny bit they have as margin for various launch conditions), you might have a bigger piece left if you try to hit the water along the right axis.
NASA has found old boosters in the water before, so the impact is career-ending, but not necessarily a blown-to-pieces moment.