Jump to content

DDE

Members
 View Profile  See their activity

  • Posts

    5,873

  • Joined

  • Last visited

 Content Type 

Everything posted by DDE

  1. DDE
    TBH it's only about as bad as Interstellar. Those guys too had two Tokomaks in a tiny SSTO with no rad shielding in sight. @Dave Angel, due to radiation issues, you simply can't beat the classic tailsitter rocket. But instead of using a tiny radiation shadow shield (see image), you decided to wrap your habitat around the reactor, ballooning your shielding mass a hundredfold at least, with no benefit at all. And that's assuming an atmospheric-capable craft would be taken out of LEO and thus need a-grav.
  2. DDE
    Expect hate. I'm about to start. Shawyer DOESN'T KNOW A FLYING **** about how his own "drive" works, or spacecraft engineering. It's the same person who thinks that a propulsion system with TWR in the nanodigits would allow flying cars, and that it's inherently stealthy - despite requiring ginormous amounts of electricity and rejecting most of the energy input as heat. You might as well use a Kuat Drive Yards motor from a Star Destroyer. Called it. Add millions of square meters of high-performance radiators, along with, say, a couple thousand tons of shielding for the high-energy neutrons. Not to mention that practical energy generation systems for fusion reactors have not been developed, and would likely add another ten thousand tons.
  3. DDE
    Oi! @OlivierRevilo, you necroed a really old thread. On a really old topic. The only two combat spacecraft ever flown looked like this:
  4. DDE
    Yep, we're set back about twenty years unless the standard Angara manages to get a life.
  5. DDE
    I do happen to have a calculator for Falcon 9R first stage with Dragon 2 right on top of it, along with a dV calculator for suborbital hops. Anyone interested?
  6. DDE
    https://kommersant.ru/doc/3310777 So, a whole bunch of announcements. Angara-A5P man-rated heavy booster is cancelled. Federatsiya's inaugural flight is to take place from Baikonur in 2022. It will be integrated with Feniks/Baiterek/fat Zenit with a 4.1 m RD-170M first stage. Vostochnyi will not receive a manned flight infrastructure until 2025, when a pad for a yet-undetermined Moonshot superheavy is to enter service.
  7. DDE
    ...is hydrolox the right propellant combo to tie yourself to? Containing the stuff seems nightmarish compared to methane, it looks like no cooling is enough because the damned thing still diffuses through the holes between the atoms of the tank. Also, I'll admit I find LEO propellant caches that are replenished by additional missions from Earth, especially with non-reusable tankers, quite dubious.
  8. DDE
    @sevenperforce, 17D15 maneuver thruster, syntin-gaseous O2 bipropellant, 4 kN thrust, 275-295 sec ISP (top value for prograde thrusters with extended nozzles), up to 2000 pulses of 0.06-1200 sec at 8 Hz with 90% nominal thrust achieved in 0.06 sec; electric inductive ignition, mixed regenerative-radiative cooling. Vernier RCS - 200 N, 265 sec ISP, 5000 pulses of 0.06 to 0.12 sec, with an oxidizer-rich mixture ratio of 3.5-4.
  9. DDE
    Or you can have regular liquid oxygen for even slightly higher ISP. 30 days orbital life is good enough for a crew-cargo ferry, and I imagine there are good reasons why HTP as an oxidizer has been largely ditched. Looks fast enough. I'm going to go look for actual tech specs. And that was apparently regular gasoline.
  10. DDE
    Variable-geometry wings appear to be a dead end. They were popular back before the deployment of fourth-generation fighters with their advanced aerodynamics and fly-by-wire. I think a lot can be saved by using a kerolox system for boost, OMS and RCS. It's not unprecedented.
  11. DDE
    They are parachute-equipped.
  12. DDE
    Ahem...
  13. DDE
    OK, why hasn't anyone mentioned the Rombus? To jump back on my Russian high horse, I do wonder what such a vehicle would come out looking like if it used tripropellant motors, with the drop tanks carrying kerolox while the center stage is hydrolox.
  14. DDE
    My own idea for am Evolved Energiya includes two stage sizes - 4.1 Baiterek core, rail-transportable, and 8 m Energiya core, air-transportable. The system covers everything from upper-medium to the superheavy class, by using one-to-three 4.1 m or an 8 m with two-to-six 4.1 m strap-ons as the first stage, possibly with propellant crossfeed, and 4.1 or 8 m upper stages. It would of course put the ULA range out of business; no reusability decreases initial costs. The big idea is using methalox on all stages. First stage engine would be the RD-0141, derived from RS-25E-equivalent RD-0120; four for an 8 m and one per each 4.1 m. Upper stage motors would either be two or four RD-190s (heavily upgraded RD-120s) with telescoping nozzle extenders. Evolved upper stages would use RD-0140s, a new member of the RD-4xx solid-core fission thermal rockets family, or the coveted RD-600 vortex-confined gas-core nuclear thermal motor, but that is way over budget. The old Energiya pads were rated for Vulkan's eight RD-170 strap-ons, so they should be usable considering they've survived N-1 "launches". Methane/LNG infrastructure is quite affordable. I don't have any math for it.
  15. DDE
    I know that one and it's not what I mean. NERVA was constrained by the choice of pressure vessel and fuel assembly design and materials; even within the constraints of a solid-core design higher Isp and thermal output (thrust) could be achieved.
  16. DDE
    NERVA is significantly constrained by its design. There may be hotter equivalents that might achieve a TWR of 4.
  17. DDE
    I haven't ever heard of an actual design that combined an airbreather an a NERVA, though.
  18. DDE
    To spare the ugly translation: this is a proposed upgraded version of the TKS spacecraft and its return vehicle. It has a hatch right through the heatshield, like the Blue Gemini. Just a broad variety of trunks and main propulsion units; the front mounts a combination of a regular LES mast and a retrorocket and extra life support package.
  19. DDE
    @magnemoe, chill, it's just the PPTK Federatsiya in the PPTK-Z variant, which stores a very familiar-looking OM in the aft interstage, requiring an even more familiar transposition, docking, and extraction.
  20. DDE
    Do I smell a Dragon-Soyuz?
  21. DDE
    BBC is being stupid again, and I'm not sure Yuzhnoi can get anywhere close to building a MAKS replica. But otherwise it's a well-worked concept.
  22. DDE
    Gleb Evgeniyevich Lozino-Lozinskiy
  23. DDE
    Well, all we got is proof of NASA warp drive research.
  24. DDE
    What would you do without the Association for subordinate officials of the head office management of the Danube steamboat electrical services?
  25. DDE
    No love for the Grundstücksverkehrsgenehmigungszuständigkeitsübertragungsverordnung or the Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft?
×
×
  • Create New...