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Size: 6781
Comment:
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Size: 7239
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 14: | Line 14: |
| $ \mu = 3.98600448e14 {m^3}/{s^2} = ? \omega^2 a^3 $ | $ \mu = 3.98600448e14 {m^3}/{s^2} ~ \buildrel{?}\over{=} ~ \omega^2 a^3 = 3.988154435e14 = 1.000539376 \mu $ |
| Line 16: | Line 16: |
| The difference is probably due to J2 causing both perigee and the mean motion to get dragged forward. However, because LAGEOS is in a highly inclined orbit, the equations I have (from Piscane, page 113) suggests it should get dragged backwards. Meanwhile, those same equations suggest that M288 must be about 3.4 kilometers higher to counteract the extra acceleration due to $ J_2 $ MORE LATER |
The Lageos measurement satellites
Two passive satellites are used for laser geodesy. These are 60 centimeter, 400 kilogram solid metal spheres covered with retroreflectors, used for precisely measuring the geometry of the Earth's surface and the Earth's gravitational field.
m288 is 1200km above LAGEOS 1. Server sky orbits should stay above LAGEOS!
These satellites are interesting because their orbits are very precisely defined, and we can use them to verify both our orbital math and learn about drag at those extreme altitudes.
\mu = 3.98600448e14 {m^3}/{s^2} ~ \buildrel{?}\over{=} ~ \omega^2 a^3 = 3.988154435e14 = 1.000539376 \mu
The difference is probably due to J2 causing both perigee and the mean motion to get dragged forward. However, because LAGEOS is in a highly inclined orbit, the equations I have (from Piscane, page 113) suggests it should get dragged backwards. Meanwhile, those same equations suggest that M288 must be about 3.4 kilometers higher to counteract the extra acceleration due to J_2
MORE LATER
Orbital elements from various sources
|
LAGEOS 1 |
LAGEOS 2 |
- nyo |
||
NORAD ID |
8820 |
22195 |
Int'l Code |
1976-039A |
1992-070B |
Perigee |
5,845.9 km |
5,622.3 km |
Apogee |
5,954.4 km |
5,959.4 km |
Inclination |
109.8° |
52.6° |
Period |
225.5 min |
222.5 min |
Semi major axis |
12,271.2 km |
12,161.9 km |
Launch date |
May 4, 1976 |
October 22, 1992 |
Source |
United States |
Italy |
- JPL |
||
mass |
411kg |
405kg |
diameter |
0.6m |
0.6m |
eccentricity |
0.0045 |
|
- NSSDC |
||
periapsis |
5837.0 km |
5900.0 km |
apoapsis |
5946.0 km |
5900.0 km |
period |
225.41000366210938 min |
225.0 min |
Inclination |
109.80000305175781° |
54.0° |
eccentricity |
0.00443999981507659 |
0.009999999776482582 |
- springerlink |
||
decay |
1.1mm/day 1.5V |
|
- Innovateus |
||
mass |
406.965 |
405.38 |
|
||
spin |
0.61s |
0.906s |
|
||
period( sec ) |
13246.002197265628 |
|
\large\omega |
4.743457847e-4 |
Two Line Elements
LAGEOS1 TLE:
- 1 08820U 76039A 11094.82079485 +.00000016 +00000-0 +10000-3 0 01141
- 2 08820 109.8462 077.3556 0044210 050.5232 309.9115 06.38664784558975
LAGEOS2 TLE:
- 1 22195U 92070B 11095.53472161 -.00000009 00000-0 10000-3 0 3192
- 2 22195 052.6462 175.4139 0138581 279.8295 078.6642 06.47294193436229
# |
chars |
description |
LAGEOS 1 |
LAGEOS 2 |
1 |
01-01 |
Line number |
1 |
1 |
2 |
03-07 |
Satellite number |
08820 |
22195 |
3 |
08-08 |
Classification (U=Unclassified) |
U |
U |
4 |
10-11 |
International Designator (Last two digits of launch year) |
76 |
92 |
5 |
12-14 |
International Designator (Launch number of the year) |
039 |
070 |
6 |
15-17 |
International Designator (Piece of the launch) |
A |
B |
7 |
19-20 |
Epoch Year (Last two digits of year) |
11 |
11 |
8 |
21-32 |
Epoch (Day of the year and fractional portion of the day) |
094.82079485 |
095.53472161 |
9 |
34-43 |
First Time Derivative of the Mean Motion divided by two |
+.00000016 |
-.00000009 |
10 |
45-52 |
Second Time Derivative of Mean Motion |
+00000-0 |
00000-0 |
11 |
54-61 |
BSTAR drag term (decimal point assumed) |
+10000-3 |
10000-3 |
12 |
63-63 |
The number 0 (formerly "Ephemeris type") |
0 |
0 |
13 |
65-68 |
Element number |
0114 |
319 |
14 |
69-69 |
Checksum (Modulo 10) |
1 |
2 |
|
||||
1 |
01-01 |
Line number |
2 |
2 |
2 |
03-07 |
Satellite number |
08820 |
22195 |
3 |
09-16 |
Inclination [Degrees] |
109.8462 |
052.6462 |
4 |
18-25 |
Right Ascension of the Ascending Node [Degrees] |
077.3556 |
175.4139 |
5 |
27-33 |
Eccentricity (decimal point assumed) |
0044210 |
0138581 |
6 |
35-42 |
Argument of Perigee [Degrees] |
050.5232 |
279.8295 |
7 |
44-51 |
Mean Anomaly [Degrees] |
309.9115 |
078.6642 |
8 |
53-63 |
Mean Motion [Revs per day] |
06.386647845 |
06.472941934 |
9 |
64-68 |
Revolution number at epoch [Revs] |
58975 |
36229 |
10 |
69-69 |
Checksum (Modulo 10) |
5 |
9 |
. . . 11094 = April 4, 2011 . . . 11095 = April 5, 2011
References: