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DerekL1963

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Everything posted by DerekL1963

  1. DerekL1963
    The federal government is not allowed to compete with private industry.
  2. DerekL1963
    o.0 It's trivial to imagine a simpler, safer, and more reliable system - just replace the Draco thrusters with solid fuel motors. You've eliminated all the moving parts, all the pressurized components, and the corrosive, carcinogenic, and toxic propellants in one fell swoop.
  3. DerekL1963
    Given that space fanbois can't seem to get and keep the difference straight, I seriously doubt the American public will be able to either. Doubly so given their general lack of ability to discern the difference between Congress having their thumb on the scales and effing up the result and screw ups or inefficiency on the part of the actual organization. With very few rare exceptions, it's the organization (like NASA or the National Park Service) that get the blame.
  4. DerekL1963
    Which is still (it seems to me, no offense) somewhat wide of the mark. Developing SLS wasn't NASA's idea, and it's not their screwup that they got the order reversed - Congress ordered NASA to develop SLS, and dictated it's basic design. NASA is truly between a rock and a hard place - it's an agency of the Executive Branch, but the Executive has almost totally ceeded authority over it to the Legislative Branch.
  5. DerekL1963
    Boeing is a private company, not a government agency. Boeing making unsolicited proposals means Boeing is looking for business, not that the Moon is on the table. Nobody (with any authority to do so) has established any requirements for an actual mission for either SLS or Orion. Nor is anyone likely to do so any time soon (read: at the earliest, after ISS deorbit) because of the sharp rise in NASA budget that will be required. *sigh* Do folks not actually grasp that the Senate Launch System is nothing more than a vehicle to deliver pork to key Congressional districts and contractors? Please, stop treating as if it's something NASA developed on it's own hook and is now a screwup because NASA doesn't have any payloads for it.
  6. DerekL1963
    It's not so much inclination as orbital period and inclination. A relatively low polar orbit might bring you in range of your target only every twenty four hours or so.
  7. DerekL1963
    There's more to it than just "the N1 had too many engines". The Saturn V first stage was test fired as a stage - the N1 was test fired as individual engines which were then assembled into a stage and launched. Given that the N1 was a rush job that skipped an important step, I think that's an unproven assertion. We simply don't know if there is an upper bound for a properly designed and tested booster.
  8. DerekL1963
    Folks who haven't been away from fresh vegetables cannot possibly appreciate how incredibly welcome this will be. I served on an SSBN (which launched the test missile in my userpic), and at the end of patrol the inspection teams would traditionally bring a couple of cases of tomatoes and a couple of cases of lettuce onboard with them. A couple of times I was on the crew loading them, and we'd open a case and bite into a tomato or a head of lettuce like it was an apple. Sliders (hamburgers) were traditionally lunch that day, and a lot of guys would skip the meat and just make a lettuce and tomato sandwich. This is way more important for morale than a 'patch of green'.
  9. DerekL1963
    Not really, because unless you're really lucky it'll almost always be at least hours away from being into a position to be deorbited onto target. If you're playing Global Thermonuclear War, a weapon that's unpredictable as to availability and won't be for hours or days might as well not exist.
  10. DerekL1963
    That's pretty much only true of the Saturns and the Shuttle.
  11. DerekL1963
    I'm was waiting for someone to figure out that you're being trolled rather expertly.
  12. DerekL1963
    o.0 That's exactly how NASA has procured rockets for decades.
  13. DerekL1963
    Apollo 6, the second (unmanned) Saturn V/CSM test. And mind you, being saved by engine out was a bit of a fluke. It wasn't supposed to have engine out capability in the first place because it was thought that the gimbals and the flight control system wouldn't be able to compensate. (Also keep in mind that even though it was trying to, the cause of the engine out didn't lead to unplanned disassembly.) And saving is perhaps a bit of an overstatement, they had to use the CSM's SPS to circularize and as a result didn't have enough delta-V to accelerate the CSM enough to meet the re-entry parameters. (It was supposed to simulate a lunar re-entry by using the SPS to accelerate the stack before SM jettison.) In fact, AFAIK, none of the "saved from engine out" flights to date (the Shuttle had two ATO due to insufficient thrust) actually saved the entire mission.
  14. DerekL1963
    Found a clever use for KAC... I'm testing the thermal design of a new LV-N powered craft, and need to know what the heat levels are if it doesn't blow up. I fire up the engines and set a raw time alarm tied to the vehicle, set to pause at completion. That way, even if I wander off during the 15 minute burn, the status of the vehicle is 'frozen' until I come back.
  15. DerekL1963
    From your own link: "Motive power is going to come from surplus Peacekeeper ICBM 1st stage motors." Peacekeeper motors aren't new, not by a long shot. No, Peacekeeper motors aren't 5m in diameter. It's as Nibb and Hannu2 say - an relatively cheap refurbished motor in a fairly cheap adapter. No doubt much cheaper than a Delta IV. Not to mention the tests are taking place at White Sands, where there is neither a Delta IV launch pad nor the infrastructure for handling the amount of cryogenics a Delta IV requires. (Which is the real answer as to why they're developing a new launcher at modest cost.)
  16. DerekL1963
    Delta IV.
  17. DerekL1963
    The Merlin is being heavily and rapidly upgraded because SpaceX started from the bottom from scratch with an engine designed for the misbegotten Falcon I. It has to evolve or they'd be bankrupt and the bits sold off to the highest bidder at auction. It's not like there was some huge revolution in rocket technology over the last forty years that ULA is missing out on.
  18. DerekL1963
    No, that's not a real world example because NASA's budget doesn't work that way. NASA doesn't have any of it's "own" money to spend, it all comes from Congress. If Congress funds payloads, then there are payloads. If Congress doesn't fund payloads there are no payloads. It's just about as simple as that.
  19. DerekL1963
    Read DBowman's post above - you need a model of your RCS system and it's performance.
  20. DerekL1963
    Yes. Yup. And before you get to that there's also going to be a longish period during which 'normal' oil extraction will yield a product that's too expensive to use for cars or Happy Meal toys, but not too expensive for specialized uses (like rockets). Even with reusables and price reductions, the hydrocarbons would have to increase in price considerably (more than tenfold, less than a hundred fold) before they become a cost driver.
  21. DerekL1963
    You can't calculate it, not directly anyhow. You need to work through your reference mission plan, measuring the RCS fuel required at each step, and then sum up those amounts and add in a bit for reserves. If the results are significantly different from those you used to generate your mission plan, you need to rework your weights and mission plan and start over again. Spacecraft design (even at the theoretical level) is an iterative process. This is one of the reasons why NASA has spent such effort coming up with reference mission designs for Mars missions - they're the foundation that underlies everything else. The other reason is that it's cheap and makes them look busy. An awful lot of NASA studies and "planning" are conducted for this reason - and who knows, maybe they'll get funded.
  22. DerekL1963
    o.0 The Soviets had some important and showy 'firsts', but by middle of the Gemini program (when we had mastered rendezvous and docking and were starting to get a handle on EVA and the Soviets had neither) the US had pulled ahead and remained there to the end of the Space Race era (the Lunar landing). They wouldn't even break the "longest total time in space" as well as "longest single time in space" we established during Skylab until 1977 - and it took eleven missions and (IIRC) four or five different stations to accomplish that.
  23. DerekL1963
    There are explosives on the rocket itself. Usually some kind of linear charge to cut holes in the fuel tank and disperse the fuel.
  24. DerekL1963
    No, we don't. We have a proposal that's not actually on a bar napkin because Robert Zubrin translated his handwaving into the formal language of a scientific paper. And that's pretty much where the matter rests, there's been no analysis or simulation done at any significant level. Nobody knows if the thing will actually work or not. And to answer the OP's original question, no, it's not possible.
  25. DerekL1963
    AIUI, propulsive landings are really only possible with relatively modern computing and inertial technology. Also, the effects if the Shuttle's engine plume on the first stage are going to be... interesting. Also, also, developing a throttleable F-1A is going to be a very, very expensive and difficult challenge. Big motors like that have impressive amounts of response lag. I've been meaning to say that for a couple of days now... In all these discussions of extending the I/Ib, folks are forgetting why it was abandoned in the first place.
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