Differences between revisions 24 and 30 (spanning 6 versions)

Earth Orbits

Orbits are complicated, because they involve both position and velocity in three spatial dimensions and time. Simple two-body "Kepler" orbits relate the position and velocity at one time to the position and velocity at other times. In reality, orbits are also complicated by drag, light pressure, and gravitational perturbations by other bodies, and in the extreme by relativistic effects. For this discussion, we will not consider the complications, so that we get closed-form algebraic solutions. Of course, in real life, we will need to include all the complications in our calculations of orbital properties. Server-sats are deployed in closely packed orbital families. One central orbit, perfectly circular and in the orbital plane, with a sidereal period of 14393 seconds and a radius of 12789 kilometers, surrounded by slightly inclined and slightly elliptical orbits that fill a toroidal region around that central orbit. By carefully assigning orbital parameters, this region can be filled with densely packed orbits and objects in them.

Describing Earth Orbits

Orbits are ellipses in a plane which also contains the center of the mass that defines the orbit.

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Earth Orbit Parameterms

system	status	number	planes	#/plane	perigee	apogee	inclination	period	uplink GHz	downlink GHz
Space Station	in use	1	1	1	6727	6736	51.6	5480	x	x
Iridium	in use	66	6	11	7158	7158	86.4	6027	Ka band	Ka band
Teledesic	bankrupt	288	12	24	7778	7778	98.2	6827	28.6-29.2	18.9-19.3
Globalstar	in use	48	x	x	7792	7792	52	6845	x	x
m288 core	empty	0	1	0	12789	12789	0	14393	x	x
m288 outer	empty	0	many	0	12739	12839	2.24	14393	x	x
Molniya	in use	3?	3?	1	7885	45683	63.4	43082	x	x
GPS	in use	31	6?	-	26600	26600	55	43082	x	x
GEO	in use	361	1	-	42164	42164	0 to 14.3	86164	-	-
Moon	natural	1	1	1	364397	406731	5.14	2360592	x	x

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M orbits

orbit	passes	radius	radius	altitude	sidereal	max	45N max	45N azim	45N	visible	rads
	/ day	km	RE	km	per secs	latitd	elevation	degrees	ping ms	fraction	/sec
m120	12	7639	1.2	1261	6645	33.5	-10.2	---	---	---	2e-4
m160	9	9099	1.4	2721	8638	45.6	0.6	22.5	43	0.04	6e-3
m240	6	11540	1.8	5162	12338	56.5	12.4	97.1	56	0.21	8e-3
m288	5	12789	2.0	6411	14393	60.1	16.5	109.9	63	0.25	2e-3
m360	4	14441	2.3	8063	17271	63.8	20.6	121.1	73	0.29	2e-3
m480	3	16756	2.6	10378	21585	67.7	24.8	131.5	87	0.32	2e-3
m720	2	20295	3.2	13917	28774	71.7	29.1	141.4	110	0.35	2e-2
m1440	1	26586	4.2	20208	43141	76.1	33.5	151.4	150	0.39	1e-2
GEO	0	42164	6.6	42164	86164	81.3	38.2	162.4	253	0.43	5e-4

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References

Wikipedia : Orbit

Wikipedia : Orbital Elements

Wikipedia : Two Line element description (with SGP4 fortran)

Ellipse Geometry Review (pdf)

OrbitSoftware

Notes on GPS satellite orbits

SaVi satellite constellation visualization

Encyclopedia Astronautica

Description of NORAD 2 line elements

NORAD Space Tracking Information requires account.

Celestrak

Real Time Satellite Tracking

NASA 3D Realtime Satellite Tracker (Java)

Geosynchronous Satellites

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-  ⇤ ← Revision 24 as of 2009-03-22 17:59:09 → 
  Size: 4796
  Editor: KeithLofstrom
  Comment:
+   ← Revision 30 as of 2009-10-06 03:25:12 → ⇥
  Size: 5605
  Editor: KeithLofstrom
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
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-=== Well Known Earth Orbits ===
+=== Earth Orbit Parameterms ===

||  system           || status   || number || planes || #/plane || perigee || apogee || inclination ||  period || uplink GHz || downlink GHz ||
|| Space Station     || in use   ||   1    ||    1   ||    1    ||   6727  ||   6736 ||    51.6     ||    5480 ||      x     ||      x       ||
|| Iridium           || in use   ||   66   ||    6   ||   11    ||   7158  ||   7158 ||    86.4     ||    6027 ||  Ka band   || Ka band    ||
|| Teledesic         || bankrupt ||  288   ||   12   ||   24    ||   7778  ||   7778 ||    98.2     ||    6827 ||  28.6-29.2 ||  18.9-19.3   ||
|| Globalstar        || in use   ||   48   ||    x   ||    x    ||   7792  ||   7792 ||    52       ||    6845 ||     x      ||      x       ||
|| '''m288 core'''   || empty    ||    0   ||    1   ||    0    ||  12789  ||  12789 ||     0       ||   14393 ||     x      ||      x       ||
|| '''m288 outer'''  || empty    ||    0   || many   ||    0    ||  12739  ||  12839 ||     2.24    ||   14393 ||     x      ||      x       ||
|| Molniya           || in use   ||    3?  ||    3?  ||    1    ||   7885  ||  45683 ||    63.4     ||   43082 ||     x      ||      x       ||
|| GPS               || in use   ||   31   ||    6?  ||    -    ||  26600  ||  26600 ||    55       ||   43082 ||     x      ||      x       ||
|| GEO               || in use   ||  361   ||    1   ||    -    ||  42164  ||  42164 ||  0 to 14.3  ||   86164 ||     -      ||      -       ||
|| Moon              || natural  ||    1   ||    1   ||    1    || 364397  || 406731 ||     5.14    || 2360592 ||     x      ||      x       ||

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-||  system           || status      || number || planes || #/plane ||  perigee || apogee || inclination || period       || uplink GHz || downlink GHz ||
|| Space Station || in use      ||     1       ||    1       ||      1      || 6727      ||   6736   ||   51.6        ||  5480        ||    x             ||       x               ||
|| Iridium             || in use      ||    66      ||     6    ||       11    ||  7158     ||    7158   ||     86.4      || 6027         ||  Ka band    ||   Ka band       ||
|| Teledesic        || bankrupt ||   288     ||    12     ||      24    ||   7778    ||   7778   ||    98.2       || 6827         ||  28.6-29.2  ||  18.9-19.3      ||
|| Globalstar       || in use     ||     48      ||     x     ||       x      ||   7792    ||    7792   ||      52        || 6845         ||    x              ||      x              ||
|| '''m288 core'''  ||  empty?   ||     0      ||     1     ||       0      ||  12789   ||  12789   ||       0         ||  14393      ||    x              ||      x             ||
|| '''m288 outer''' ||  empty?   ||     0      ||     1     ||       0      ||  12289   ||  13289   ||    2.24       ||  14393      ||    x              ||      x             ||
|| Molniya           || in use      ||    3?      ||     3?   ||       1     ||   7885    ||  45683    ||    63.4      || 43082      ||    x             ||      x               ||
|| GPS                || in use      ||    31     ||     6?    ||       -      || 26600   ||  26600   ||    55          ||    43082    ||    x             ||        x             ||
|| GEO               || in use      ||   361     ||     1     ||       -      ||  42164   ||  42164   ||  0 to 14.3  ||  86164      ||    -             ||       -             ||
|| Moon              || natural    ||    1        ||     1     ||       1      || 364397  || 406731  ||  5.14         ||  2360592  ||    x             ||      x               ||
+=== M orbits ===

|| orbit || passes || radius || radius || altitude || sidereal || max    ||  45N max  || 45N azim ||   45N   || visible  || rads ||
||       || / day  ||   km   ||   RE   ||    km    || per secs || latitd || elevation || degrees  || ping ms || fraction || /sec ||
|| m120  ||   12   ||   7639 ||   1.2  ||    1261  ||    6645  ||  33.5  ||   -10.2   ||   ---    ||   ---   ||   ---    || 2e-4 ||
|| m160  ||    9   ||   9099 ||   1.4  ||    2721  ||    8638  ||  45.6  ||     0.6   ||   22.5   ||   43    ||   0.04   || 6e-3 ||
|| m240  ||    6   ||  11540 ||   1.8  ||    5162  ||   12338  ||  56.5  ||    12.4   ||   97.1   ||   56    ||   0.21   || 8e-3 ||
|| m288  ||    5   ||  12789 ||   2.0  ||    6411  ||   14393  ||  60.1  ||    16.5   ||  109.9   ||   63    ||   0.25   || 2e-3 ||
|| m360  ||    4   ||  14441 ||   2.3  ||    8063  ||   17271  ||  63.8  ||    20.6   ||  121.1   ||   73    ||   0.29   || 2e-3 ||
|| m480  ||    3   ||  16756 ||   2.6  ||   10378  ||   21585  ||  67.7  ||    24.8   ||  131.5   ||   87    ||   0.32   || 2e-3 ||
|| m720  ||    2   ||  20295 ||   3.2  ||   13917  ||   28774  ||  71.7  ||    29.1   ||  141.4   ||  110    ||   0.35   || 2e-2 ||
|| m1440 ||    1   ||  26586 ||   4.2  ||   20208  ||   43141  ||  76.1  ||    33.5   ||  151.4   ||  150    ||   0.39   || 1e-2 ||
|| GEO   ||    0   ||  42164 ||   6.6  ||   42164  ||   86164  ||  81.3  ||    38.2   ||  162.4   ||  253    ||   0.43   || 5e-4 ||
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-{{{#!wiki caution
'''Volunteer Opportunity: Space Debris Orbits ''' The Norad Two Line Elements (TLEs) for all tracked satellites and space debris are available for individuals signing up at www.space-track.org (see references).  It would be very useful to build a program that can go through all the two line elements, and look for orbits that cross the equatorial plane in the vicinity of m288 .  How many are there?
}}}
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+[[ http://www.oc.nps.edu/~garfield/ellipse_app2.pdf | Ellipse Geometry Review (pdf) ]]

Diff for "EarthOrbits"

Earth Orbits

Describing Earth Orbits

Earth Orbit Parameterms

M orbits

References