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 |
sem.lat. |
launch V |
orbit V |
kick V |
plane change V from loop latitude |
|
ISS |
6780 km |
6615 km |
7480 m/s |
7668 m/s |
94 m/s |
134 m/s/° |
altitude only, ISS incl. 51.65°, inaccessable |
M288 |
12789 km |
8580 km |
8586 m/s |
5583 m/s |
1009 m/s |
97 m/s/° |
|
GEO |
42164 km |
11200 km |
9875 m/s |
3075 m/s |
1490 m/s |
54 m/s/° |
|
Moon |
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 |
Mars |
|
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.