Differences between revisions 1 and 3 (spanning 2 versions)

Earth To Orbit

A table of launch information.

Destination	Launch V	2000km	2000km	10 gee	10 gee	transit	Arrival	altitude	radius
	V m/s	gees	time s	dist km	time s	hrs	∆V m/s	km	km
LEO	7451	1.41	537	283	76	0.74	65	300	6678
m288	8586	1.88	466	376	88	1.30	1009	6411	12789
GEO	9875	2.49	405	497	101	5.24	1490	35786	42164
Moon	10547	2.84	379	567	108	119.42	833	378022	384400
Slingshot Moon to m288	10547	2.84	379	567	108	241.74	-2184	6411	12789
Slingshot Moon to GEO	10547	2.84	379	567	108	255.56	-1053	35786	42164

Note that the slingshot orbits show negative arrival ∆V. With some kind of rotating or linear tether system at the arrival orbit, the positive ∆V from ground launch payloads and the negative ∆V from a slingshot payloads can be averaged. This greatly reduces the size of the orbital insertion kick motors needed to inject payloads into these orbits. By sending 30% of m288 payloads the long way around the moon, for example, the cost of delivering payloads to m288 could be halved.

Rotating Tether orbits

Apogee can be circularized without big rocket motors by using rotating tethers. Assume 3 gees centifugal force on the tether ends, 5 ton payloads (150kN), with some sort of magic that briefly reduces the attach shock. There will probably be a fairly large counterweight in the middle, or else the tether will be much more massive than necessary for one payload, so less added velocity is needed to make up for payload deltaV reduction. The added velocity may come from returning payloads, or from loop-launched mass passing tangentially by the rotating tether in a fast orbit from above or below, possibly with lunar slingshot assist. Mad handwaving here.

Destination	Circular	Delta V	Perigee	Perigee	Apogee	Apogee	Length	Period	Tether
	m/s	m/s	V m/s	R km	V m/s	R km	km	sec	Mass kg
LEO	7726	65	7825	6566	7693	6678	0.07	3.4
m288	5583	1009	7206	9006	5078	12780	17.97	52.8
GEO	3075	1490	5788	16966	2330	42146	37.00	78.0
Moon	1018	833	2662	90975	603	384394	11.56	43.6

-  ⇤ ← Revision 1 as of 2009-07-21 15:52:11 → 
  Size: 35
  Editor: pool-71-117-189-35
  Comment:
+   ← Revision 3 as of 2009-08-24 04:47:35 → ⇥
  Size: 2980
  Editor: KeithLofstrom
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 3:
-A table of
+A table of launch information.

|| Destination            || Launch V || 2000km || 2000km || 10 gee  || 10 gee || transit || Arrival || altitude || radius ||
||                        || V m/s    || gees   || time s || dist km || time s || hrs     || ∆V m/s  || km       || km     ||
|| LEO                    || 7451     || 1.41   || 537    || 283     || 76     || 0.74    || 65      || 300      || 6678   ||
|| m288                   || 8586     || 1.88   || 466    || 376     || 88     || 1.30    || 1009    || 6411     || 12789  ||
|| GEO                    || 9875     || 2.49   || 405    || 497     || 101    || 5.24    || 1490    || 35786    || 42164  ||
|| Moon                   || 10547    || 2.84   || 379    || 567     || 108    || 119.42  || 833     || 378022   || 384400 ||
|| Slingshot Moon to m288 || 10547    || 2.84   || 379    || 567     || 108    || 241.74  || -2184   || 6411     || 12789  ||
|| Slingshot Moon to GEO  || 10547    || 2.84   || 379    || 567     || 108    || 255.56  || -1053   || 35786    || 42164  ||

Note that the slingshot orbits show negative arrival ∆V.  With some kind of rotating or linear tether system at the arrival orbit, the positive ∆V from ground launch payloads and the negative ∆V from a slingshot payloads can be averaged.  This greatly reduces the size of the orbital insertion kick motors needed to inject payloads into these orbits.  By sending 30% of m288 payloads the long way around the moon, for example, the cost of delivering payloads to m288 could be halved. 

=== Rotating Tether orbits ===

Apogee can be circularized without big rocket motors by using rotating tethers.  Assume 3 gees centifugal force on the tether ends, 5 ton payloads (150kN), with some sort of magic that briefly reduces the attach shock.   There will probably be a fairly large counterweight in the middle, or else the tether will be much more massive than necessary for one payload, so less added velocity is needed to make up for payload deltaV reduction.   The added velocity may come from returning payloads, or from loop-launched mass passing tangentially by the rotating tether in a fast orbit from above or below, possibly with lunar slingshot assist.  Mad handwaving here.
            
|| Destination || Circular || Delta V || Perigee  || Perigee || Apogee || Apogee || Length || Period || Tether  ||
||             ||  m/s     || m/s     || V m/s    || R km    || V m/s  || R km   || km     || sec    || Mass kg ||
|| LEO         ||  7726    ||   65    ||  7825    ||   6566  ||  7693  ||   6678 ||  0.07  ||   3.4  ||         ||
|| m288        ||  5583    || 1009    ||  7206    ||   9006  ||  5078  ||  12780 || 17.97  ||  52.8  ||         ||
|| GEO         ||  3075    || 1490    ||  5788    ||  16966  ||  2330  ||  42146 || 37.00  ||  78.0  ||         ||
|| Moon        ||  1018    ||  833    ||  2662    ||  90975  ||   603  || 384394 || 11.56  ||  43.6  ||         ||

Diff for "EarthToOrbit"

Earth To Orbit

Rotating Tether orbits