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'''Note''' Launch altitude may increase to 100 km to reduce drag.

Launch Loop Destinations

Launch at 80 km altitude, 6458 km radius. GM is 3.986e14 m3/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.

Note Launch altitude may increase to 100 km to reduce drag.

radius km


launch V

orbit V

kick V

plane change V from loop latitude


6780 km

6615 km

7480 m/s

7668 m/s

94 m/s

134 m/s/°

altitude only, ISS incl. 51.65°, inaccessable


12789 km

8580 km

8586 m/s

5583 m/s

1009 m/s

97 m/s/°


42164 km

11200 km

9875 m/s

3075 m/s

1490 m/s

54 m/s/°


384400 km

12700 km

10547 m/s

1018 m/s

833 m/s

487 m/s max

Moon's orbit inclined compared to Earth's axial tilt


12920 km

11002 m/s

5630 m/s

eff. escape + 2.86 m/s, kick= Mars landing

libreoffice spreadsheet destinations.ods

If the launch loop is placed south of the equator, to avoid January thunderstorms in the intertropical convergence zone (ITCZ), extra delta V will be needed after apogee kick to change orbit inclination into a circular equatorial orbit. The Moon is a special case; since its inclination varies from the Earth's equatorial plane by 23.44±5.14°, the plane change relative to the equator (and relative to a southerly offset loop) will vary. The number given for the Moon is relative to the maximum 28.58°; by launching at the right time of day and month, the loop latitude inclination reduces this.

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)