OK. Not sure if you answered my question. What I had in mind is shuttle reaching ISS orbit at MECO. If this is possible, then it seems possible that shuttle could arrive at station vicinity within first orbit (retaining enough OMS/RCS prop for nominal docking/undocking maneuvers & landing). Just wondering if possible, not whether it's desirable.
I've always been curious about the 2 days it takes for the shuttle to reach ISS. Aside from the inspections that must be done, presumably the reason for a slow approach is to conserve fuel and thus maximize payload capacity.
Just out of curiosity, is it even possible for shuttle to reach ISS in its first orbit, even an empty shuttle?
Quote from: kyle_baron on 01/29/2010 03:41 pmQuote from: Jim on 01/29/2010 03:30 pmQuote from: kyle_baron on 01/29/2010 03:20 pmThe air traveling thru the scoops must be traveling at sonic speeds with in the boat tail. And could be directed downward to the RS-68 nozzles by short ducts. I disagree about the problem existing beyond the atmosphere, because we're talking about the 1st stage only. First stage does leave the sensible atmosphere Does a sensible atmosphere exist, before the SRB's fall away? I agree that there is a "point of diminishing returns" for the air scoops, as the rocket gains altitude.it is gone maybe 30 seconds before that
Quote from: Jim on 01/29/2010 03:30 pmQuote from: kyle_baron on 01/29/2010 03:20 pmThe air traveling thru the scoops must be traveling at sonic speeds with in the boat tail. And could be directed downward to the RS-68 nozzles by short ducts. I disagree about the problem existing beyond the atmosphere, because we're talking about the 1st stage only. First stage does leave the sensible atmosphere Does a sensible atmosphere exist, before the SRB's fall away? I agree that there is a "point of diminishing returns" for the air scoops, as the rocket gains altitude.
Quote from: kyle_baron on 01/29/2010 03:20 pmThe air traveling thru the scoops must be traveling at sonic speeds with in the boat tail. And could be directed downward to the RS-68 nozzles by short ducts. I disagree about the problem existing beyond the atmosphere, because we're talking about the 1st stage only. First stage does leave the sensible atmosphere
The air traveling thru the scoops must be traveling at sonic speeds with in the boat tail. And could be directed downward to the RS-68 nozzles by short ducts. I disagree about the problem existing beyond the atmosphere, because we're talking about the 1st stage only.
2. The boat tail completly covers the RS-68 nozzles (except at the bottom, of course).
Quote from: kyle_baron on 02/12/2010 04:05 pm2. The boat tail completly covers the RS-68 nozzles (except at the bottom, of course).Not that easy. The engine exhausts hot hydrogen from the heat exchanger and roll control nozzle (which is from the turbopump exhaust). Also the nozzles have to be able to move.http://www.tallgeorge.com/images/projectconstellation/Boeing%20Rocketdyne%20RS-68%20Engine.jpg
Quote from: kyle_baron on 02/12/2010 04:05 pm2. The boat tail completly covers the RS-68 nozzles (except at the bottom, of course).Uh, no. Almost the whole nozzle is outside the heat shield.
I have a question: How is the mass of a spacecraft supposed to scale with respect to the payload it is required to carry, assuming the overall volume of the spacecraft doesn't change much?I'm thinking specifically of lunar SSTO landers where the maximum g-force wouldn't exceed 0.5 g.
Volume has no bearing for a lunar SSTO, where there is no air.
It is often said that the velocity gain achieved by airlaunch is fairly trivial, and could be matched simply by a slightly larger first stage. It is also said that the velocity generated by a simple hop to 100 km is about 3 percent of that required for orbital.
I remember reading an interview with Elon Musk where he said that SpaceX had looked into air launching. I really wish I remember where that was that I saw it! However, If I remember correctly he stated that early on SpaceX had studied it and found in terms of cost that air launch was more expensive for what they wanted to do. That's cost though not performance.