Page 1 of 2 12 LastLast
Results 1 to 15 of 26

Thread: Spacex Reusable Booster Tests Getting Serious

  1. #1
    Senior Member shuredgefan's Avatar
    Join Date
    Apr 2009
    Location
    Teegeeack-awaiting the triumphal return of Mighty Xenu
    Posts
    1,709

    Default Spacex Reusable Booster Tests Getting Serious

    After two relatively small test hops Spacex's reusable booster test-bed climbs to 40 meters, hovers for about 10 seconds and lands safely.



    A multi-camera video:



    Spacex is trying to greatly reduce the cost of boost stuff into orbit by creating reusable rockets, here's a video on the concept:

  2. #2
    Junior Member
    Join Date
    May 2011
    Location
    UK
    Posts
    11

    Default

    I would be curious to see their ideas of fuel requirements for an actual payload. As far as i understand it the plan has always been to eschew chutes completely.

    Think of the quantity of fuel used in current rockets just to put something up, now add on the fuel required to bring your stuff from terminal velocity, remember that's free-fall from orbit, to a soft landing!? And remember to add on the extra fuel to lift the extra fuel up.

    And all that extra fuel means a smaller payload or larger vehicle.

    I can see the benefit of retrieval systems for liquid rockets along the soyuz profile as being worthwhile, parachutes with retro rockets. This?

    Meh, I'm not that read up on their mission or specs at the moment. Always seen this round of development as sort of proof of concept more than producing a (economically) viable launcher. I will be watching SpaceX though. They seem to have a pretty good operations and design setup.

    Still looks awesome though and that's what matters Cheers for the vids.
    I love the mix of interests here, I tend to catch things I would never usually look up myself.

    Different field by the by so im no expert on launch vehicles

  3. #3
    Senior Member custodes's Avatar
    Join Date
    Jul 2008
    Location
    Save the world, off a shrink.
    Posts
    11,495

    Default

    And non-government space launches interest me.

  4. #4
    Senior Member shuredgefan's Avatar
    Join Date
    Apr 2009
    Location
    Teegeeack-awaiting the triumphal return of Mighty Xenu
    Posts
    1,709

    Default

    [*******#000000][FONT=Arial]Despite the dangers, Musk is clearly a fan of the rocket-powered approach. He told PM that SpaceX has come up with a solution to make both the lower and upper stages of the Falcon 9 reusable. (The Dragon capsule that will fly atop the rocket has already demonstrated that it can be recovered in the ocean after it splash-lands with a parachute, though SpaceX is building vertical-landing capability into that as well.) [/FONT][/COLOR]

    [*******#000000][FONT=Arial]The key, at least for the first stage, is the difference in speed. "It really comes down to what the staging Mach number would be," Musk says, referencing the speed the rocket would be traveling at separation. "For an expendable Falcon 9 rocket, that is around Mach 10. For a reusable Falcon 9, it is around Mach 6, depending on the mission." For the reusable version, the rocket must be traveling at a slower speed at separation because the burn must end early, preserving enough propellant to let the rocket fly back and land vertically. This also makes recovery easier because entry velocities are slower. [/FONT][/COLOR]

    [*******#000000][FONT=Arial]However, the slower speed also means that the upper stage of the Falcon rocket must supply more of the velocity needed to get to orbit, and that significantly reduces how much payload the rocket can lift into orbit. "The payload penalty for full and fast reusability versus an expendable version is roughly 40 percent," Musk says. "[But] propellant cost is less than 0.4 percent of the total flight cost. Even taking into account the payload reduction for reusability, the improvement is therefore theoretically over a hundred times." [/FONT][/COLOR][*******#000000][FONT=Arial]

    Read more: Elon Musk on SpaceX’s Reusable Rocket Plans - Popular Mechanics[/FONT][/COLOR]
    I bet they did a lot computer modeling before they started on this road

  5. #5
    Senior Member Roebuck's Avatar
    Join Date
    Oct 2011
    Posts
    1,123

    Default

    As an Aviator, and an Engineering student. this interests me greatly.

  6. #6
    Senior Member
    Join Date
    Jul 2003
    Location
    Australia
    Age
    34
    Posts
    3,414

    Default

    Very cool stuff. The concepts coming out of SpaceX are pretty awesome.

    A 40% penalty to payload is rather hefty though.

  7. #7
    How's that Hopey Changey thing workin'? C.Puffs's Avatar
    Join Date
    May 2010
    Location
    Leading maxima10 around by the nose.
    Posts
    23,837

    Default

    Quote Originally Posted by skiplicker View Post
    I would be curious to see their ideas of fuel requirements for an actual payload. As far as i understand it the plan has always been to eschew chutes completely.

    Think of the quantity of fuel used in current rockets just to put something up, now add on the fuel required to bring your stuff from terminal velocity, remember that's free-fall from orbit, to a soft landing!? And remember to add on the extra fuel to lift the extra fuel up.

    And all that extra fuel means a smaller payload or larger vehicle.

    I can see the benefit of retrieval systems for liquid rockets along the soyuz profile as being worthwhile, parachutes with retro rockets. This?

    Meh, I'm not that read up on their mission or specs at the moment. Always seen this round of development as sort of proof of concept more than producing a (economically) viable launcher. I will be watching SpaceX though. They seem to have a pretty good operations and design setup.

    Still looks awesome though and that's what matters Cheers for the vids.
    I love the mix of interests here, I tend to catch things I would never usually look up myself.

    Different field by the by so im no expert on launch vehicles
    The Space Shuttle wasted something like 172,000lbs of payload every flight (for the Orbiter itself). That's why the Shuttle's payload was always listed as 65,000lbs despite the fact that it was throwing a Saturn V's payload into orbit every flight.

  8. #8
    Member _GDS_'s Avatar
    Join Date
    Aug 2005
    Location
    Lithuania, Vilnius
    Age
    28
    Posts
    625

    Default

    reusable sounds great, but fuel requirement for the job is just enormous(i think)!
    the other problem might be more serious, reusable, don't you think after that returning heat it may become 1 use only (i'm talking not about heat shield), all parts will get stress on them.

  9. #9
    Senior Member shuredgefan's Avatar
    Join Date
    Apr 2009
    Location
    Teegeeack-awaiting the triumphal return of Mighty Xenu
    Posts
    1,709

    Default

    Quote Originally Posted by Ballistic View Post
    Very cool stuff. The concepts coming out of SpaceX are pretty awesome.

    A 40% penalty to payload is rather hefty though.

    Yeah, but remember that after the next launch, they're going to the F9 ver 1.1 with 13 tons (metric) to LEO. 60% of 13 is 7.8, which is still pretty respectable. (1)

    Also, the payload penalty for the Falcon Heavy would probably be slightly less because the cross-feeding side cores will separate at a slower velocity and lower altitude than the Falcon 9 booster, although the middle core will also be almost orbital (or even orbital) so recovering that one may be too problematical.


    (1) http://www.spacex.com/Falcon9UsersGuide_2009.pdf


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


    Why is making a reusable rocket so difficult:




    Quote Originally Posted by _GDS_
    [*******#333333]reusable sounds great, but fuel requirement for the job is just enormous(i think)![/COLOR]
    [*******#333333]the other problem might be more serious, reusable, don't you think after that returning heat it may become 1 use only (i'm talking not about heat shield), all parts will get stress on them.[/COLOR]
    I saw an interview with Mr Musk where he said that the initial retro burn on the booster was to slow it down enough that frictional heating wouldn't necessitate an extensive heat shield and that almost all of the return trip to the launch site would be accomplished aerodynamically.
    Last edited by shuredgefan; 12-25-2012 at 04:59 PM.

  10. #10

    Default

    Quote Originally Posted by skiplicker View Post
    I would be curious to see their ideas of fuel requirements for an actual payload. As far as i understand it the plan has always been to eschew chutes completely.

    Think of the quantity of fuel used in current rockets just to put something up, now add on the fuel required to bring your stuff from terminal velocity, remember that's free-fall from orbit, to a soft landing!? And remember to add on the extra fuel to lift the extra fuel up.

    And all that extra fuel means a smaller payload or larger vehicle.

    I can see the benefit of retrieval systems for liquid rockets along the soyuz profile as being worthwhile, parachutes with retro rockets. This?

    Meh, I'm not that read up on their mission or specs at the moment. Always seen this round of development as sort of proof of concept more than producing a (economically) viable launcher. I will be watching SpaceX though. They seem to have a pretty good operations and design setup.

    Still looks awesome though and that's what matters Cheers for the vids.
    I love the mix of interests here, I tend to catch things I would never usually look up myself.

    Different field by the by so im no expert on launch vehicles
    It's not about a slow down from orbit...LOL...it's about recovering the first stage of the rocket. Man ... that's something what the Zenith was designed for 30 years ago, with a different principle but basicaly the same purpose. And yes it's very much worht it, rocket engines of the first stage, and the stage/tank it self make quite a fine percent in launch price. So may I recommend a quick read on Energia launcher (I hope you know that Zenith was used as a booster stage on Energia and that todays USA space workhorse the Atlas rocket is using Zeniths engines) and some highschool textbooks on physics, cheers.

  11. #11

    Default

    not seeing this going anywhere unless they can reduce the penalty to less than 15%
    semi powered glide is the best bet so far.

  12. #12
    Senior Member shuredgefan's Avatar
    Join Date
    Apr 2009
    Location
    Teegeeack-awaiting the triumphal return of Mighty Xenu
    Posts
    1,709

    Default

    Quote Originally Posted by tadeus View Post
    It's not about a slow down from orbit...LOL...it's about recovering the first stage of the rocket. Man . And yes it's very much worht it, rocket engines of the first stage, and the stage/tank it self make quite a fine percent in launch price.
    Quote Originally Posted by Revive View Post
    not seeing this going anywhere unless they can reduce the penalty to less than 15%
    semi powered glide is the best bet so far.

    The main problem of space flight is now cost, a 40% payload penalty makes the reusable rocket highly in​efficient in all measures except the most important, cost.

  13. #13

    Default

    Quote Originally Posted by shuredgefan View Post
    The main problem of space flight is now cost, a 40% payload penalty makes the reusable rocket highly in​efficient in all measures except the most important, cost.
    The debate is similar to cost per sit or cost per miles.
    today the industry measures by cost per weight, this idea brings down the cost of the rocket by what? The net profit will almost certainly less than 40%. But on other hand payload drops 40%. Put this into an excel, you will see the denominator affects the result far greater than numerator.

  14. #14
    How's that Hopey Changey thing workin'? C.Puffs's Avatar
    Join Date
    May 2010
    Location
    Leading maxima10 around by the nose.
    Posts
    23,837

    Default

    Quote Originally Posted by tadeus View Post
    So may I recommend a quick read on Energia launcher (I hope you know that Zenith was used as a booster stage on Energia and that todays USA space workhorse the Atlas rocket is using Zeniths engines) and some highschool textbooks on physics, cheers.
    Do they actually recover those engines? I'd think if they were reusable the Soviets back in the day would have done like the US shuttle and mounted the engines on the orbiter.
    Last edited by C.Puffs; 12-25-2012 at 09:24 PM.

  15. #15
    Senior Member shuredgefan's Avatar
    Join Date
    Apr 2009
    Location
    Teegeeack-awaiting the triumphal return of Mighty Xenu
    Posts
    1,709

    Default

    Quote Originally Posted by Revive View Post
    The debate is similar to cost per sit or cost per miles.
    today the industry measures by cost per weight, this idea brings down the cost of the rocket by what? The net profit will almost certainly less than 40%. But on other hand payload drops 40%. Put this into an excel, you will see the denominator affects the result far greater than numerator.
    Um, you know that reusable rocket production capital costs are divided by the number of times you can use them, while expendable rocket costs are divided by the number one. Fuel being about 0.5% of launch cost.


    Here's the full speech to the NPC, it's pretty good:


    Talks about the reusable program around 16:00 and the economies at 20:45.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •