Differences between revisions 1 and 2
 ⇤ ← Revision 1 as of 2016-07-25 05:24:21 → Size: 1389 Editor: KeithLofstrom Comment: ← Revision 2 as of 2016-07-25 05:26:49 → ⇥ Size: 1541 Editor: KeithLofstrom Comment: Deletions are marked like this. Additions are marked like this. Line 5: Line 5: || || radius km || launch V || kick V || || || radius km || launch V || kick V || Line 13: Line 13: Saving perhaps 200 m/s of delta V on a Mars rocket launch is significant. Not for a launch loop. It is more important to save delta V for the kick.

# Launch Loop Destinations

Launch at 80 km altitude, 6458 km radius. GM is 3.986e14 m2/s2, day is 86164 seconds, escape velocity is 11111 m/s. rotation velocity 471 m/s, effective escape 10640 m/s . Not including air drag on the way out, which will be significant.

 radius km launch V kick V ISS 6780 km 7480 m/s 94 m/s inclination 51.65°, inaccessable from equatorial plane launch M288 12789 km 8586 m/s 1009 m/s GEO 42164 km 9875 m/s 1490 m/s Moon 384400 km 10547 m/s 833 m/s Moon's orbit inclined compared to Earth's axial tilt Mars 11002 m/s 5630 m/s sum of squares, eff. escape + 2.86 m/s

Note that gravity assist from the Moon reduce the Mars launch velocity a tiny bit - but not much, because the vehicle must leave the Moon at precisely the right direction (tangential to Earth's orbit) and velocity ( 2860 m/s added to the Earth's 29,800 m/s solar orbital velocity to be in a Hohmann orbit to Mars, and this must happen at precisely the right window to reach Mars when it gets there. These windows happen every 780 days, and the Moon will be in the wrong place most of those days. The vehicle can take a faster orbit than a Hohmann (with a higher delta V at each end) and accomodate some "wrongness") but not much.

Saving perhaps 200 m/s of delta V on a Mars rocket launch is significant. Not for a launch loop. It is more important to save delta V for the kick.

Destinations (last edited 2017-03-01 01:46:47 by KeithLofstrom)