In reply to Jed Rothwell's message of Fri, 16 Jan 2015 23:08:00 -0500: Hi, [snip] ><[email protected]> wrote: > > >> One would think that it ought to be possible to significantly reduce the >> weight >> of the first stage of a rocket by using jet engines iso rocket engines. >> That way >> you save the weight of the Oxygen (by far the heaviest component), by using >> environmental air. > > >Yup. That's called an air-launched rocket. The SpaceShipOne is an example.
Actually what I had in mind was more something with just jet engines iso rocket engines, not something carried into the air on the back of a jet. (This should be possible, because the Harrier jump jet is capable of vertical takeoff, on jet exhaust alone.) Though maybe air-launched turns out to be more efficient &/or cheaper? > >I guess the first air-launched rocket was the X-1, launched from a B-29 >bomber. They also managed to take off from the ground once, but it was >designed to be air-launched. > >A space elevator would have many advantages but with the early models it >would take a long time to reach the geosynchronous terminal. Days or weeks. >It might be possible to slowly send a small rocket up a few hundred >kilometers, well above the atmosphere, drop it, and have it space-launch >from there to make a quick trip to the terminal, in a few hours. I think >this would take less fuel than going through the atmosphere. I wouldn't >want to ride in it! > >- Jed Space elevators should never be built. Far too dangerous (read "Red Mars"?) and unstable (wind problems). Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
