Page 2 of 2 FirstFirst 12
Results 16 to 25 of 25

Thread: Spacex Reusable Booster Tests Getting Serious

  1. #16

    Default

    Quote Originally Posted by shuredgefan View Post
    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.
    I know what exactly I am talking about, but I failed to make you understand my point.
    The situation here is too much idealized talk but still struggling in fixing the math problem. With as much as 40% penalty you pretty much looking at firing a Saturn 5V for every Soyuz delivery. While on other hand, powered glide use aerodynamic forces to deliver the vehicle, involving a much greater efficiency in using fuel thus has a better chance in this direction.
    For example two equivalent reusable design. Case 1, equals in cost per launch, Grasshopper $50k/1.3tonne vs Glider $50k/(1.3*1.4)tonne. Case 2, equals in payload per launch, Grasshopper $50k*1.05/1.3 vs Glider $50*C/1.3. Which C is always smaller than 1.05 as long as T/W is not equals to 1. In any case, Grasshopper losses.

  2. #17
    Senior Member Xaito's Avatar
    Join Date
    Sep 2004
    Age
    28
    Posts
    13,769

    Default

    I would not have expected somebody to put research into rockets these days. If we really want to breathe new life into space travel, we should be looking at new ways to do that instead of trying to squeeze out a few more percent out of available tech. Personally I find space elevators / space tethers and mass drivers / space guns most interesting.

  3. #18
    Junior Member
    Join Date
    May 2011
    Location
    UK
    Posts
    11

    Default

    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.
    Easy tiger http://www.hw.ac.uk/ I got my BEng there.

    It's been some time since I actually used orbital mechanics. Rocket science is, funnily enough, actually quite easy. The energies involved not so.
    Turbomachinery does not last forever. Yes it's expensive to design and build but if the recovery costs are low enough it becomes viable to retrieve them. At higher launch prices the cost of recovery versus the benefit of overhauling the engines (or rather the associated systems) can become, ahem, prohibitive.

    I tried for an overall supportive tone, I do find the field interesting, just not my day job.
    Last edited by skiplicker; 12-27-2012 at 07:13 PM. Reason: clarity

  4. #19
    Senior Member
    Join Date
    Oct 2005
    Posts
    1,996

    Default

    Quick question could this technology be created for use on ”asteroids” or places where gravity differs from earth’s gravity for instance Moon or Mars as part of some other system.

    Considering Elon Musk is involved in spacex and seeing that he usually aims a bit further down the road than what he usually publicly states could it be for use in something else than “reusable rockets on earth” or is this his “Spruce goose” http://en.wikipedia.org/wiki/Hughes_H-4_Hercules

  5. #20
    Senior Member Martel's Avatar
    Join Date
    Feb 2007
    Location
    Paris, France
    Posts
    2,056

    Default

    Quote Originally Posted by tadeus View Post
    (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)
    FYI, Zenith uses RD-171 [SIZE=1](non-steerable RD-170 as Energia booster)[/SIZE] which is a four combustion chambers engine, Atlas uses RD-180 which is a two chambers version of the RD-170/171

  6. #21

    Default

    Quote Originally Posted by Martel View Post
    FYI, Zenith uses RD-171 [SIZE=1](non-steerable RD-170 as Energia booster)[/SIZE] which is a four combustion chambers engine, Atlas uses RD-180 which is a two chambers version of the RD-170/171
    Yes, I know all that, I was trying to point to something else. I have been following the SpeceX's advance and development for some time. It's really pleasing to see them advance so well. In my opinion the key of their sucess lies in (beside a very prominent and competent CEO) engineering and development of unique technologies.

    But have you noticed a new feature of the Dragon vehicle that was shown on the animations. I didn't find or noticed anything writen on the subject and If we assume it's not just for easier animation sequence it looks like the Dragon will soon get an automated rendezvous and docking capability. So far only Soyuz has it , also Chinese copy and the ESA vehicles are using Russian build systems. I'm look forward to see the SpaceX designed system in real action.

  7. #22
    Senior Member Einhander's Avatar
    Join Date
    Jun 2011
    Location
    SPb
    Age
    34
    Posts
    3,270

    Default

    The whole Uragan idea was about saving costs - each booster involved would return on its own, automatically gliding back to airfield.




    SpaceX variant, however, could provide proven technologies to make a completely "returnable" rocket to visit lowgrav bodies like the Moon or Mars.

  8. #23

    Default

    Quote Originally Posted by Einhander View Post
    The whole Uragan idea was about saving costs - each booster involved would return on its own, automatically gliding back to airfield.




    SpaceX variant, however, could provide proven technologies to make a completely "returnable" rocket to visit lowgrav bodies like the Moon or Mars.
    I think we have to call it almost completely "returnable" rocket since the service and engine compartment of the Dragon or any other cargo that actualy reaches orbit is not returnable. Anyway SpaceX is on the right track. Wish them space free of any debris.
    And on the topic in the animation we can see that only rocket engines are used for deceleration. Why not combine it with parachutes like on the Zenith boosters? I must guess that they have already run all the cost-weight simulations on that in SpaceX, did they?

  9. #24
    Senior Member Martel's Avatar
    Join Date
    Feb 2007
    Location
    Paris, France
    Posts
    2,056

    Default

    Quote Originally Posted by tadeus View Post
    But have you noticed a new feature of the Dragon vehicle that was shown on the animations. I didn't find or noticed anything writen on the subject and If we assume it's not just for easier animation sequence it looks like the Dragon will soon get an automated rendezvous and docking capability.
    The manned version will have it, the cargo version doesn't have it because it uses the "big" CBM which can't be "hard-docked". That's why Dragon and Japanese HTV are captured and berthed to the ISS.

    Quote Originally Posted by tadeus View Post
    So far only Soyuz has it , also Chinese copy and the ESA vehicles are using Russian build systems. I'm look forward to see the SpaceX designed system in real action.
    ATV uses the mechanical Russian probe & drogue design, but the automated RDV system is European and not Russian. It uses LIDAR, but KURS is still used as informational only system.

  10. #25
    Senior Member Martel's Avatar
    Join Date
    Feb 2007
    Location
    Paris, France
    Posts
    2,056

    Default

    Getting higher ...


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
  •