Page 1 of 163 1231151101 ... LastLast
Results 1 to 30 of 4931

Thread: SpaceX

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Aug 2013
    Posts
    324

    Smile SpaceX

    Hello. I find the 'SpaceX' story an interesting one. They seem to be using landing legs to return the first stage of the rocket to hopefully be re-used.

    Question: Why has this not been done before?

    #2. I don't see other rocket builders doing the same thing. Why? Could it be that they cannot afford to do so?

    Bye
    SC

  2. #2
    Join Date
    Sep 2009
    Posts
    4,468
    Quote Originally Posted by Gorn View Post
    Hello. I find the 'SpaceX' story an interesting one. They seem to be using landing legs to return the first stage of the rocket to hopefully be re-used.

    Question: Why has this not been done before?

    #2. I don't see other rocket builders doing the same thing. Why? Could it be that they cannot afford to do so?

    Bye
    SC
    It's been worked on but some of the projects ran into various issues to do with mission profiles and budgets. DC-X successfully made landings but was hampered by political infighting and possibly being over ambitious in that the long term aim of the project was a Single Stage To Orbit(SSTO) vehicle. Details are here. DC-X did apparently provide an inspiration for the current work being done by Blue Origin. Japan had the RVT program that was successful but so far hasn't led to any further developments.

    SpaceX are limiting their work at the moment to a reusable first stage, which somewhat simplifies things. Added to which they can do testing using existing hardware and working it into other programs; i.e. testing the landing legs on the next CRS flight.

  3. #3
    Join Date
    Feb 2009
    Posts
    511
    NASA is struggling to even have a rocket and is heavily hamstrung by political concerns, so is ESA but for different reasons, and ULA (Lockheed/Boeing) are more interested in lobbying for a monopoly so they can keep selling their current expensive launchers forever. The Russian space program has relatively little money but there's been rumblings of their budget going up, so that might change things. India has talked about reusable rockets but it's something still firmly in the future. China I don't really know about - do they have any plans?

    Basically, due to various reasons SpaceX are the only ones with the will and means to do it. They've demonstrated that any number of organizations could have done it with a modest investment, they've just chosen not to. It's kinda sad but I'm happy at least someone is trying.

  4. #4
    Join Date
    Mar 2004
    Posts
    19,980
    Quote Originally Posted by Gorn View Post
    Hello. I find the 'SpaceX' story an interesting one. They seem to be using landing legs to return the first stage of the rocket to hopefully be re-used.

    Question: Why has this not been done before?
    For one thing, it's hard. Musk has made that clear himself. He has stated he wasn't sure reusable was practical, though lately he has said he's become much more confident that it is.

    When you get down to it, you're dealing with a small margin that represents the payload, so extra mass that's going to trajectory requirements, a landing system, and the fuel for landing could use up the margin. Then too, you want a rocket that's fairly robust, so it is practical to reuse it. Incidentally, this makes more sense with a larger rocket, since the payload fraction is small.

    In early plans, the Space Shuttle was supposed to be something like this, with a fly back first stage. That got lost to budget compromises, and the whole thing became extremely expensive. And compare the development of the Space Shuttle, where they finally were going to do an engine upgrade (which would have stopped the need to rebuild the engines after each flight) right about the time it was taken out of service, to SpaceX where they've already had a major engine upgrade and are now working on a methane fuel rocket. The space shuttle should have been through at least two major design generations with more upgrades during the flight of those generations to resolve the high maintenance and high operating cost aspects. But as a government program, operating cost wasn't anywhere near their top priority, so it didn't happen.

    #2. I don't see other rocket builders doing the same thing. Why? Could it be that they cannot afford to do so?
    The most important thing has always been to get the spacecraft to orbit. The traditional aerospace companies have been getting paid plenty for military and NASA work, and don't want to rock the boat. They will only work on something new if they're getting paid for it (like various X programs). Also, there is a strong tendency by engineers to keep using what works, especially for these highly critical systems. It took somebody from outside the system to rock the boat. Musk isn't the first to try - there have been some other commercial attempts, but this is a hugely expensive and difficult market to break into. Part of the reason Musk has a chance is because the conditions are changing.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." ó Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  5. #5
    Join Date
    Sep 2009
    Posts
    4,468
    Quote Originally Posted by Van Rijn View Post
    The most important thing has always been to get the spacecraft to orbit. The traditional aerospace companies have been getting paid plenty for military and NASA work, and don't want to rock the boat. They will only work on something new if they're getting paid for it (like various X programs). Also, there is a strong tendency by engineers to keep using what works, especially for these highly critical systems. It took somebody from outside the system to rock the boat. Musk isn't the first to try - there have been some other commercial attempts, but this is a hugely expensive and difficult market to break into. Part of the reason Musk has a chance is because the conditions are changing.
    That has been the problem; the market in space launchers has been pretty stagnant and until COTS efforts to stir it up hadn't really succeeded.

  6. #6
    Join Date
    Feb 2011
    Posts
    2,080
    Musk's fortune from Solar City, and especially Tesla, has grown to the point where he can self-finance many projects. Almost $12 billion according to Bloomberg, more according to others.

    This also lets him borrow against stock to finance projects or upgrades. Gives him other funding options as well.

    It's good to be rich.
    Last edited by docmordrid; 2014-Mar-10 at 11:07 AM.

  7. #7
    Join Date
    Sep 2009
    Posts
    4,468
    Quote Originally Posted by docmordrid View Post
    Musk's fortune from Solar City, and especially Tesla, has grown to the point where he can self-finance many projects. Almost $12 billion according to Bloomberg, more according to others.

    This also lets him borrow against stock to finance projects or upgrades. Gives him other funding options as well.

    It's good to be rich.
    And don't forget SpaceX has a very healthy order book as well.

  8. #8
    Join Date
    Dec 2007
    Posts
    1,664
    It's great that at least some folk with visions beyond 'make myself richer tomorrow' are able to get rich.

  9. #9
    Join Date
    Sep 2009
    Posts
    4,468
    Quote Originally Posted by marsbug View Post
    It's great that at least some folk with visions beyond 'make myself richer tomorrow' are able to get rich.
    I think there are two kinds of rich people basically; those who look at their big pile of money and simply want to keep that pile or make it bigger. Then you have the ones who look at it and think; 'probably should find something useful to do with that'.

  10. #10
    Glom's Avatar
    Glom is offline Insert awesome title here
    Join Date
    Sep 2002
    Posts
    11,357
    The guy is quite inspiring.