SpaceX Successfully Lands Reusable Rocket

Dec 22, 2015

After two previous failed attempts, SpaceX has finally managed to land one of its 15-storey tall Falcon 9 rocket boosters back on earth. Watch the video below of the launch and landing (and a bit of SpaceX staff cheering).

22 comments on “SpaceX Successfully Lands Reusable Rocket

  • Yes, every science fiction movie I saw as a kid had rockets landing like this. This will make space travel far cheaper, not throwing the equipment away every time you fly. You’ve got to take your hat off to Elon, like with Tesla, has had loads of knockers but works out how he thinks it should work then does that. Very little in the way of compromise. Remarkable bloke.



    Report abuse

  • The private developers are building on some of the technologies which were abandoned or put on hold, when the US moved over to use the space shuttle to dominate launch systems.

    Computer control systems have also greatly moved forward since those times.



    Report abuse

  • 4
    rocket888 says:

    Now that we have a Buck Rogers landing vehicle from the ’40s maybe now, we’re ready for a spinning wheel space station (circa ’60 in AC’s 2001) so people don’t have to work in zero g.

    But I’m really happy to see private developers doing work in space. Maybe with artificial gravity, we’ll see a space Hilton some day soon.



    Report abuse

  • Yes, didn’t mean to take the line I’ve seen particularly with some of the competitors that only private enterprise can do space efficiently. I remember watching a talk given by Burt Rutan who won the prize for spaceship 1. He was shooting his mouth off at how great they were for being this little company and making all sorts of comparisons between them and NASA and while I am a tremendous fan of Rutan going way back into my teenage years for his R&D in planes and I also know he would not have been able to do so without NASA having gone there first. The amount of accumulated, freely available information gained from what went before them, they can only do these things because of who an what went before. I would think even more highly of Rutan if he could acknowledge this fact but apparently his ego doesn’t allow him to go there (at least not in the talk I saw).

    There is a point in that often government funded projects fall under certain pressures such as developing your spacecraft in several different states to please senators who you need to please, or the shuttle for example being compromised by having to fit greater sized payloads than originally intended to get funding at all. So commercial companies can often come up with great stuff cheaply but often not until a lot of work has gone before, often freely provided ultimately by the tax payer in the form of basic research. Elon I believe isn’t patenting his technology with this on the basis he said that how effective is a patent when realistically your major competitors are governments like China and Russia. So sort of making his rockets open source, I think we could see much of this technology and innovation bleeding into all the space programs, particularly now they know it can be done.



    Report abuse

  • Hi Phil,

    They are obviously going to have to carry enough fuel to slow the descent from about 2000 ft if I remember correctly from the video I saw at an earlier stage. However the atmosphere will do most of the slowing it would be falling at terminal velocity (whatever that is for a rocket) by the time he is in the lower atmosphere it will have slowed significantly. Of course it’ll be a lot lighter going down with most of the fuel burnt on the way up. Every kilo of fuel carried is a kilo of payload they cannot carry. But you can afford to do that if you are not throwing out your 50 million dollar rocket on every launch, I imagine payload loss becomes insignificant compared to that cost. If he needed to lift a greater load they could always join a few rockets together. He’s also saving money in other ways, he’s using basically the same rocket motors on all his rockets scaled up and down and 3D printing them in one piece, so he’s keeping thinks as simple as possible from what I understand, a lot of this will come down to very good software and sensors controlling the descent.



    Report abuse

  • rocket888
    Dec 23, 2015 at 7:43 pm

    maybe now, we’re ready for a spinning wheel space station (circa ’60 in AC’s 2001) so people don’t have to work in zero g.

    I think the earlier versions are likely to be 2 habitation capsules on the end of a long boom or a power unit on one end and a habitation capsule on the other.

    These would be rotated end over end, and would not need to be as massive as a wheel.

    The could also be used for inter planetary flight with a habitation unit on one end, and an engine on the other. It would have to be de-spun before firing the engine. A clever addition would be a 1G thrust engine.

    The might even get away with an attachment cable between the two units while coasting.
    Alternatively an interplanetary craft could have two balanced ends on a boom rotating at 90 degrees to the flight path, with an electric drive ion engine in the middle of the boom providing steady thrust.



    Report abuse

  • Does this take much from the orbital payload capacity?

    Not very much Phil, as Reckless Monkey has already explained. This particular mission was the first to use superchilled oxygen, permitting about 20% more densified oxygen to enhance performance. Usually oxygen is chilled to -298F degrees but this latest iteration is -340F degrees and the kero is also chilled slightly. Also this version is slightly taller too, further adding to the amount of propellant.

    Returning the first stage from its 200km apogee requires three burns using only three of its nine engines. The first is known as a boostback burn to reverse the trajectory back towards the landing site, which is close to the launch site. This involves reorienting from about 6000 km/hr and roughly 20 or 30 miles downrange, to head back.
    Next event is the re-entry burn to slow the rocket and prevent it being damaged by the extreme frictional heat associated with hypersonic re-entry. Finally the landing burn is a single engine event from about 2000 ft which decelerates from terminal velocity to achieve a pinpoint landing. Very impressive stuff.



    Report abuse

  • Reckless, Len,

    Many thanks for this info. I recall the 3D printed engines….a perfect application for technology fusing high strength from from structural detail and perfect flow forms straight off the simulations.

    Getting such landing finesse from single engine control is indeed a real achievement.



    Report abuse

  • phil rimmer
    Dec 24, 2015 at 12:30 pm

    Many thanks for this info. I recall the 3D printed engines….a perfect application for technology fusing high strength from from structural detail and perfect flow forms straight off the simulations.

    I recall that discussion on 3D printed rocket engine components.

    NASA is continuing to work on research in association with industry.

    http://www.nasa.gov/centers/marshall/news/news/releases/2015/piece-by-piece-nasa-team-moves-closer-to-building-a-3-d-printed-rocket-engine.html
    Piece by Piece: NASA Team Moves Closer to Building a 3-D Printed Rocket Engine



    Report abuse

  • Hi Phil,

    I was under the impression it was a number of engines but of the same design and different motors being used in different stages, adding to the complexity. One of the complications with some of the other rocket designs is they often use more than one type of motor. Essentially my understanding is Musk has where ever possible used the same motor design and not mixed and matched different components. The small motors he used for the pilot capsule he’s designed are essentially the same also just scaled down. But I could be wrong when I read up about all this they were still doing early testing launching it a couple of thousand feet up then landing again. Hopefully someone here has looked into it a little more. Regardless it’s an impressive demonstration of application of maths and science to do something that for so long has been put in the too hard basket, too hard no longer it would seem.

    A lot of what he is doing with the Tesla cars follows the same logical approach. For example his design of the cars and power systems allows for many different technologies to be applied as they come up, currently lithium battery banks but could easily use fuel cells or supe caps whatever he isn’t having to completely re-tool or re-design the car, so the technology he is developing doesn’t tie him to any particular outcome. These things give you hope for humanity.



    Report abuse

  • Hi Alan4Discussion, Phil,

    I’m going away for a few days so probably won’t get this reply for a bit, but I’ve been wondering about the laser sintered metal 3D printers in terms of heat treating. You and Phil are much better read than I, I though you might have heard something.

    I know from my flying days the 6061t6 aluminum’s strength is greatly effected by the temper of the metal. So the t6 in this case was the designation for the type of heat treatment. I also know that mig was was not allowed to be used on aircraft only tig and oxy due to the instant local heat and fast local cooling causing different crystallization near the weld and making the join more brittle near the weld whereas due to the more gradual heating a cooling down of the oxy process causing less of an issue in this regard.

    I wonder about the 3D printing with powered metals and lasers, do they require further heat treating (do they need to be heated up and cooled down of does the application of heat from layers above the transfer down and gradually like oxy or are the parts restricted to uses where flexibility is not an issue? Though you might have an idea, being much better read than me. I know that cooling on the plastic 3d printers is an issue depending on the material being used, we use heated beds on the ABS printers to keep the parts from warping die to the difference between the layers added still hot compared the layers below cool they tend to lift and warp. Sometimes cool breezes can quickly cool a top layer causing it to split. I don’t know how this goes with the metal printers, they tend to be enclosed and end up surrounded by the power around them. Any ideas? Thanks in anticipation of any answer.



    Report abuse

  • I was under the impression it was a number of engines but of the same design and different motors being used in different stages, adding to the complexity.

    Assuming interest I’ll continue. Tom Mueller designed the Merlin engine used by SpaceX and the same engine is used throughout, excepting the nitrogen reaction control thrusters for fine control and those used by the launch abort system, known as SuperDraco.

    All models and each stage of the Falcon rocket employ the same engine. Initial boost uses either 9 or 27 Merlins, while the second stage has just one vacuum Merlin, optimised for use beyond the atmosphere with a larger nozzle.

    Phil’s reference to a single engine was in response to the news that merely one engine was needed for a precise landing. The boostback and the hypersonic re-entry burn use 3 engines.

    This video shows their aspirations for Falcon Heavy.
    https://www.youtube.com/watch?v=4Ca6x4QbpoM&feature=youtu.be

    Musk said the payload hit for RTLS (Return To Launch Site) is 30% vs a 15% payload hit for landing on a downrange ocean platform.
    More powerful engines are being developed using methane in lieu of kerosene.

    The turbopump and the injectors are the only components manufactured using 3D printing to date.



    Report abuse

  • These things give you hope for humanity.

    Agreed Reckless.

    As with Tesla, Musk hasn’t sought patent protection for any of this. His detractors claimed recoverable rockets were impossible. His super-chilled oxygen system was also considered to be impossible.

    Anyone can replicate his automotive or rocketry breakthroughs, and Musk often says that he hopes that they will do.



    Report abuse

  • I recall that discussion on 3D printed rocket engine components.

    https://www.richarddawkins.net/2015/09/mit-invents-breakthrough-3d-printer-that-can-print-10-different-materials-simultaneously/

    Reckless Monkey
    Dec 24, 2015 at 7:04 pm

    Hi Alan4Discussion, Phil,

    Any ideas? Thanks in anticipation of any answer.

    I’m not sure, but there should be some scope for adjustments by adjusting the mix of elements in the alloys, to give a gradation of properties



    Report abuse

Leave a Reply

View our comment policy.