dsmith@hplabsb.HP.COM (David Smith) (06/25/90)
In article <721@digi.lonestar.org> msissom@digi.lonestar.org (Marc Sissom) writes: >If a launch directly into a transfer was done, >there would be no need for an SSME restart. Also savings in fuel, since you don't have to raise perigee out of the atmosphere. However, the parking orbit allows more freedom in placement of the virtual launch pad. >Does the OMS have enough capacity to brake into a lunar orbit, >then transfer back into an earthbound trajectory? I hardly think so. The shuttle news clips mention delta-V from OMS around 300 mph (maybe double: 300 to get up, and 300 to get down). Firing into and out of lunar orbit takes about 2 x 3000 mph delta-V. That's pretty close to the amount needed for translunar injection from LEO. -- "Some fear that Newtonian physics | David R. Smith, HP Labs governs superpower relations: | dsmith@hplabs.hp.com What goes up must come down." | (415) 857-7898 Time Magazine, interviewing Gorbachev, June 4, 1990