Quote from: mlorrey on 09/07/2011 08:50 amJim cannot leave Earth, if he did, the NSF forums would become overrun by naive dreamers and overoptimistic people with can-do attitudes.And what have you done lately that involves actual hardware getting into space?I just point out that modifying launch vehicles is not the same as car mods/conversions.
Jim cannot leave Earth, if he did, the NSF forums would become overrun by naive dreamers and overoptimistic people with can-do attitudes.
For the first FH launch it is adding risk and complexity for the payload to be anything other than an oversized Sputnik that returns TV pictures.If SpaceX use a high orbit they will have to add a means of de-orbiting the satellite.
The fact is that FH's real use is going to be either fuel depots in orbit or sending large loads BEO.
{snip}The fact is that FH's real use is going to be either fuel depots in orbit or sending large loads BEO.
Quote from: grr on 09/07/2011 07:01 pm{snip}The fact is that FH's real use is going to be either fuel depots in orbit or sending large loads BEO.If SpaceX wants to start off the fuel depots they could launch a tank containing about 45 mT of propellant, a docking port, the same docking aids used by the ISS and station keeping thrusters. Sun shields etc. can wait for a later version.They would have to use a fuel that neither freezes nor boils in LEO.
Has Jim ever agreed with anything Swallow has said?
Quote from: Jason1701 on 09/07/2011 11:11 pmHas Jim ever agreed with anything Swallow has said?I've been watching for just that. Though, TBH, if God and jim disagreed, I feel God would have some serious explaining to do.{snip}
Quote from: Diagoras on 09/08/2011 12:34 amQuote from: Jason1701 on 09/07/2011 11:11 pmHas Jim ever agreed with anything Swallow has said?I've been watching for just that. Though, TBH, if God and jim disagreed, I feel God would have some serious explaining to do.{snip}On the demo flight it would be nice for the fuel to be used but is not necessary. SpaceX just needs to prove that they can lift the mass.For a demo of the launch vehicle the dummy payload needs the absolute minimum that can go wrong. The limits on the propellant come from our current technology, zero boil-off technology has not reached TRL 9. That rules out hydrogen.
The real question will should be: What will the dummy mass weight? What will the final orbit be?Will they go for a max capacity mass, or a fraction of the max mass? LEO? HEO? Transfer Orbit?An argument can be made for going for max mass. If the vehicle under performs, the dummy sat will not make the desired orbit ( and depending on the orbit, may not even make orbit). From a PR stand point it is safer to go with a smaller mass. My WAG, since this is Vandenberg, a large, but not max mass to a short lived LEO Polar orbit.
Something like drop the mass simulator off in one orbit then reignite the upper stage a few more times after some loiter periods.
Quote from: A_M_Swallow on 09/08/2011 12:44 pmOn the demo flight it would be nice for the fuel to be used but is not necessary. SpaceX just needs to prove that they can lift the mass.For a demo of the launch vehicle the dummy payload needs the absolute minimum that can go wrong. The limits on the propellant come from our current technology, zero boil-off technology has not reached TRL 9. That rules out hydrogen.It rules out anything but a dummy mass. Jeesh
On the demo flight it would be nice for the fuel to be used but is not necessary. SpaceX just needs to prove that they can lift the mass.For a demo of the launch vehicle the dummy payload needs the absolute minimum that can go wrong. The limits on the propellant come from our current technology, zero boil-off technology has not reached TRL 9. That rules out hydrogen.
A dummy mass would probably get the rocket men fired for gross professional incompetence. Without the ability to manoeuvre the payload is immediate space debris. Parts of 53 ton space objects re-entering LEO can impact the Earth at unplanned locations.
Jim, the payload on the first Falcon 9 (Dragon test article) was a bit more complicated/instrumented than the Boeing's dummy masses. It's thus not unreasonable to expect the test payload to be more complicated than giant lumps of inert metal.