Why does a geostationary satellite need to be moved?

Satellites are launched via rocket and very quickly placed into a geosynchronous transfer orbit or geostationary transfer orbit (GTO). A GTO is highly elliptic. Its perigee (closest point to Earth) is typically as high as low Earth orbit (LEO), while its apogee (furthest point from Earth) is as high as a geostationary (or equally, a geosynchronous) orbit. That makes it a Hohmann transfer orbit between LEO and GSO.

Achieving Geostationary Orbit

Using onboard spacecraft thrusters, the satellite is placed into its intended orbit longitude. where they normally stay for many years. As time passes and needs change, it can be helpful to move satellites to new orbit longitude positions. This is usually done through a process known as “Drifting”.

How do you DRIFT a Satellite???

Let’s start with the basics using the GOES 17 move as our example. On January 10th, 2023, GOES-17 will begin moving east from the orbital longitude position of 137.3° West to its new orbital longitude position of 104° West. Normally, a geosynchronous satellite like GOES-17 remains in a fixed position in the sky relative to Earth’s rotation. This won’t be the case once the drift process gets underway. During its relocation, GOES-17’s five main instruments (ABI, GLM, SUVI, SEISS, and EXIS) will be turned off and placed in safe or diagnostic mode.

Normally, satellites maintain the same distance from Earth while operational (i.e. transmitting data). When required to initiate an orbit repositioning to a further east longitude orbit position, the orbital position is gradually changed, easterly, typically over a few days or weeks till the new position is reached. (All the while avoiding all the other geostationary satellites, some of which at only 10’s of km apart!***)

To accomplish this during the drift period, GOES-17’s altitude will actually be lowered slightly (by about 60 miles). This maneuver uses the resulting increase in gravity on GOES-17 to help nudge the satellite to begin moving into its new orbital position. This actually changes the geostationary orbit to a slightly elliptical orbit. Around February 8th, as GOES-17 gets close to its new orbital position, NOAA’s operations team raises the satellite back to its normal operating altitude, which will be on February 10th, 2023.

The drift maneuver must also take into account relevant harmonics of the gravity field at the altitude of geostationary orbits, as well as solar radiation pressure and third-body perturbations caused by the Moon and the Sun.

The total distance to be traveled is 33.03 degrees. This can be calculated by subtracting the starting position (137.2) from the desired ending position (104.17). To calculate the speed, we need to divide the total distance to be traveled (33.03) by the total time available for the repositioning (36 days). This gives us a speed of 0.91 degrees per day, or 0.04 degrees per hour. Therefore, to reposition the satellite from 137.2 to 104.17, it needs to travel 33.03 degrees at a speed of 0.04 degrees per hour, starting on January 10 2023 and ending on February 15th 2023. This, of course does not take into account the orbit lowering/raising manuevers.

NOAA’s missions operations division uses this lowering and raising process any time its geosynchronous satellites need to change orbital positions.

Geostationary orbit
Altitude = 35,786 km from equator
Speed = 11,052 km/hr
Period = 23 Hours, 56 Minutes

Science Fiction writer Arthur C. Clarke first suggested the idea of communications satellites in geosynchronous orbit in the October 1945 issue of Wireless World. in a paper called “Extra-terrestrial Relays — Can Rocket Stations Give World-wide Radio Coverage?” Clarke realized that a radio relay station in space could serve a huge area of the earth’s surface, like a radio tower thousands of miles high. The area of space these satellites use is sometimes referred to as the Clarke Belt.

All Geostationary Satellites also perform station-keeping navigation. In a year, relative to the center of the Earth, a geostationary satellite travels 80 million km. A drift of only 0.01% would result in 8000 km of drift in a year if allowed to go uncorrected. Since the velocity is 2500 meters per second, an annual budget of 50 meters per second is 2% of the total velocity. This is corrected with GOES with small thrusters when needed.

Thrusters used on GOES-R Series Sats

The delta-v at apogee is provided by a high-performance 450 N (101 lbf) hypergolic Liquid Apogee Engine (LAE) using hydrazine as a fuel and MON-3 (3% nitric oxide) as an oxidizer.

>Two 22 N (5 lbf) hypergolic hydrazine bipropellant thrusters (HBTs) are used for relocation, decommissioning, and as a backup to the LAE and use the same propellants as the LAE.

>Eight 22 N (5 lbf) monopropellant hydrazine reaction engine assemblies (REAs), configured in half systems, are used for settling burns prior to LAE ignition, attitude control during LAE firings, and relocations.

>Sixteen 90 mN (20 mlbf) monopropellant hydrazine LTRs, configured in half systems, are used for momentum management and station-keeping.

>Four 225 mN (50 mlbf) arcjets are used for station-keeping. The low thrust, highly predictable, stable Liquid Apogee Engine, Hydrazine Bipropellant Thruster and Hydrazine REA and arcjets allows the payload to continually operate through thruster use.

N = Newtons, mN = Micro Newtons, lbf = Pound of force

North to South perturbations would occur if the satellite did not perform routine navigation changes.
This graphic is exaggerated to show the movement of the satellite, this, of course, would not be this great in reality

But, you may ask, what if I want to drift a satellite westward?

If there is a need to move a satellite westwards, the above procedure is modified to raise it temporarily to a higher orbit, so it gradually goes backwards in longitude.


Orbital Dynamics in action.

The graphics above and below I created using ANSYS Software Tool Kit Pro using current TLE’s (Two Line Element sets) from Celestrak.

The two mp4 graphics below, both use the same timeline (January 1st to January 7th 2023) and orbital elements, the first one is rendered in 3D, and the second is in 2D. I have included the geostationary satellites with the ‘sensors’ displayed to show the coverages as they travel in relation to the earth. I have also included Polar Orbiting Satellites such as NOAA 15,18,19 and others with their sensors shown to give you an idea of how they scan the planet from an LEO (Low Earth Orbit).

3D Rendering of both LEO Polar Orbiting Satellites and selected Geostationary Satellites

As mentioned in the article above, note the North to South perturbations of the Russian Electro L2 geostationary weather satellite and GOES-13 (EWS-G1) as they wobble up and down. Many geosats do this such as Inmarsats. In the case of satellites such as this, the ground station receiver has to track relative to the movement of the satellite. Relative to the ground station this roughly translates to a slanted figure “8”

***Note that some of these satellites are separated from each other by as little as one tenth of a degree longitude. While that may seem like very little separation, and it is, at geosatellite altitudes (nearly 36,000 km), this corresponds to an inter-satellite spacing of approximately 73 km (some are much closer together, 10 km, or just 4 seconds apart!). The major consideration for spacing of geostationary satellites is the beamwidth at-orbit of uplink transmitters, which is primarily a factor of the size and stability of the uplink dish, as well as what frequencies the satellite’s transponders receive; satellites with discontiguous frequency allocations can be much closer together.
To be thourough, one must also understand that this does not account for the majority of The GEO Belt clutter. Far bigger concern are misbehaving satellites like the Galaxy 15 “Zombiesat” and other orbital debris. 

See my article on The Kessler Syndrome

As of January 2023, there are 539 Geostationary satellites in orbit.

Name    Common name            Orbit  Inc  
                                      
 00001A  USA 148                -179.9  9.6
 12061B  YAMAL 300K             -177.1  0.0
 13036A  MUOS-2                 -177.0  2.7
 09008A  NSS-9                  -177.0  0.0
 13004A  TDRS 11                -174.3  2.9
 99046A  ABS-7                  -171.5  2.9
 02055A  TDRS 10                -171.2  8.3
 02057A  NSS-6                  -169.6  1.8
 91054B  TDRS 5                 -167.7 14.2
 00024A  USA 149 (DSP 20)       -165.5 12.1
 17004A  SBIRS GEO-4 (USA 273)  -159.5  2.2
 13050A  AEHF-3 (USA 246)       -155.0  1.8
 04008A  EUTELSAT 7A            -139.3  2.3
 00067A  AMC-6 (GE-6)           -139.1  0.0
 05046B  SPACEWAY 2             -139.0  2.0
 18022A  GOES 17                -137.4  0.1
 22021A  GOES 18                -137.0  0.0
 13041A  WGS F6 (USA 244)       -135.3  0.0
 00081B  AMC-8 (GE-8)           -135.0  2.6
 99060A  AMC-4 (GE-4)           -135.0  1.7
 05041A  GALAXY 15 (G-15)       -133.0  0.0
 01011A  EUTELSAT 133 WEST A    -132.9  3.9
 04017A  AMC-11 (GE-11)         -131.1  0.1
 96054A  AMC-1 (GE-1)           -131.0  5.8
 03008A  USA 167                -130.2  8.2
 17026A  SES-15                 -129.2  0.0
 03013B  GALAXY 12 (G-12)       -129.1  3.4
 08063A  CIEL-2                 -128.9  0.0
 10008A  GOES 15                -128.1  0.4
 03044A  GALAXY 13 (HORIZONS-1) -127.1  0.0
 20056C  GALAXY 30 (G-30)       -125.1  0.0
 08038B  AMC-21                 -125.0  0.1
 01009A  USA 157 (MILSTAR-2 2)  -124.3 10.1
 08024A  GALAXY 18 (G-18)       -123.1  0.0
 03034A  GALAXY 23 (G-23)       -121.0  0.1
 95060A  USA 115 (MILSTAR-1 2)  -120.1 13.5
 05019A  DIRECTV 8              -119.1  0.0
 10010A  ECHOSTAR 14            -119.0  0.0
 07009A  ANIK F3                -118.8  0.0
 16038B  EUTELSAT 117 WEST B    -117.1  0.0
 13012A  EUTELSAT 117 WEST A    -116.9  0.0
 13058A  FM-6                   -116.2  0.1
 96020A  INMARSAT 3-F1          -116.0  7.7
 20096A  SXM-7                  -115.4  0.0
 10053A  XM-5                   -115.3  0.0
 11059A  VIASAT-1               -115.2  0.0
 15010B  EUTELSAT 115 WEST B    -115.0  0.0
 12075B  MEXSAT 3               -114.9  0.0
 15056A  MORELOS 3              -113.2  3.6
 06020A  EUTELSAT 113 WEST A    -113.0  0.0
 97065A  USA 134                -112.4 11.1
 21118A  STPSAT-6               -111.7  0.0
 06054A  WILDBLUE-1             -111.2  0.0
 04027A  ANIK F2                -111.2  0.0
 09035A  TERRESTAR-1            -111.1  3.3
 06003A  ECHOSTAR 10            -110.2  0.0
 02023A  DIRECTV 5 (TEMPO 1)    -110.2  1.3
 08035A  ECHOSTAR 11            -110.1  0.0
 17014A  ECHOSTAR 23            -110.0  0.0
 00076A  ANIK F1                -109.3  1.6
 02062A  NIMIQ 2                -109.3  6.1
 95019A  AMSC 1                 -107.5 12.0
 05036A  ANIK F1R               -107.4  0.7
 13014A  ANIK G1                -107.4  0.0
 12035A  ECHOSTAR 17            -107.2  0.0
 16041A  MUOS-5                 -105.1  5.5
 04041A  AMC-15                 -105.1  0.1
 17063A  SES-11 (ECHOSTAR 105)  -105.0  0.0
 09033A  GOES 14                -104.6  0.5
 11035A  SES-3                  -103.1  0.1
 15026A  DIRECTV 15             -102.9  0.0
 07032A  DIRECTV 10             -102.9  0.0
 09075A  DIRECTV 12             -102.8  0.0
 10005A  SDO                    -102.2 31.8
 10061A  SKYTERRA 1             -101.4  2.5
 06043A  DIRECTV 9S             -101.3  0.0
 10016A  SES-1                  -101.1  0.0
 19034A  AT&T T-16              -100.9  0.0
 12009A  MUOS-1                 -100.0  3.0
 14078B  DIRECTV 14              -99.3  0.0
 08013A  DIRECTV 11              -99.3  0.0
 06023A  GALAXY 16 (G-16)        -99.1  0.1
 08039A  INMARSAT 4-F3           -98.0  3.3
 16079A  ECHOSTAR 19             -97.2  0.0
 08045A  GALAXY 19 (G-19)        -97.1  0.1
 94084A  USA 107 (DSP 17)        -96.6 14.6
 16035A  INTELSAT 31 (IS-31)     -95.1  0.0
 14062A  INTELSAT 30 (IS-30)     -95.1  0.0
 07036A  SPACEWAY 3              -95.0  0.4
 02030A  GALAXY 3C (G-3C)        -94.9  0.1
 12019A  AEHF-2 (USA 235)        -94.3  3.5
 99071A  GALAXY 11 (G-11)        -93.2  3.2
 08016A  ICO G1                  -92.9  4.1
 12026A  NIMIQ 6                 -91.2  0.0
 07016B  GALAXY 17 (G-17)        -91.1  0.0
 94009A  USA 99 (MILSTAR-1 1)    -90.0 15.4
 05022A  GALAXY 28 (G-28)        -89.1  0.0
 13075A  TKSAT-1 (TUPAC KATARI)  -87.3  0.0
 11049A  SES-2                   -87.1  0.1
 02015B  ASTRA 3A                -86.8  7.5
 09034A  FM-5                    -86.2  0.0
 21049A  SXM-8                   -85.3  0.0
 06049A  XM-4 (BLUES)            -85.2  0.1
 05008A  XM-3 (RHYTHM)           -85.2  0.0
 16082B  STAR ONE D1             -84.1  0.0
 06054B  AMC-18                  -83.1  0.1
 08044A  NIMIQ 4                 -82.0  0.0
 15054B  ARSAT 2                 -81.1  0.0
 10065A  HYLAS 1                 -79.1  2.1
 15026B  SKY MEXICO-1            -78.8  0.0
 11054A  QUETZSAT 1              -77.1  0.0
 10006A  INTELSAT 16 (IS-16)     -76.3  0.0
 16071A  GOES 16                 -75.3  0.1
 12062A  STAR ONE C3             -75.1  0.0
 17023B  SGDC                    -74.9  0.0
 14011A  AMAZONAS 4A             -74.0  0.0
 09050A  NIMIQ 5                 -72.8  0.1
 01025A  ASTRA 2C                -72.5  4.7
 97050A  AMC-3 (GE-3)            -72.1  4.7
 14062B  ARSAT 1                 -71.9  0.0
 15034B  STAR ONE C4             -70.1  0.0
 21069A  STAR ONE D2             -70.1  0.0
 17029A  VIASAT-2                -70.0  0.0
 18079A  AEHF-4 (USA 288)        -67.5  2.4
 17017A  SES-10                  -67.0  0.0
 16014A  EUTELSAT 65 WEST A      -65.3  0.1
 08018B  STAR ONE C2             -65.1  0.1
 11021A  TELSTAR 14R             -63.1  0.0
 18059A  TELSTAR 19V             -63.1  0.0
 02011A  TDRS 9                  -62.3  9.1
 10034A  ECHOSTAR 15             -61.7  0.0
 12065A  ECHOSTAR 16             -61.6  0.0
 16039B  ECHOSTAR 18             -61.4  0.0
 17053A  AMAZONAS 5              -61.1  0.0
 09054A  AMAZONAS 2              -61.1  0.0
 13006A  AMAZONAS 3              -61.1  0.0
 12045A  INTELSAT 21 (IS-21)     -58.1  0.0
 15039A  INTELSAT 34 (IS-34)     -55.5  0.0
 15005A  INMARSAT 5-F2           -55.0  0.0
 98006B  INMARSAT 3-F5           -54.0  6.5
 12057A  INTELSAT 23 (IS-23)     -53.1  0.0
 13024A  WGS F5 (USA 243)        -52.6  0.0
 01039A  INTELSAT 902 (IS-902)   -50.1  2.6
 00043A  INTELSAT 9 (IS-9)       -50.0  7.3
 01033A  USA 159 (DSP 21)        -49.1 11.5
 88091B  TDRS 3                  -48.9 13.7
 18012B  SES-14                  -47.6  0.0
 93003B  TDRS 6                  -45.8 14.1
 09064A  INTELSAT 14 (IS-14)     -45.0  0.0
 17007B  INTELSAT 32E (IS-32E)   -43.2  0.0
 07044B  INTELSAT 11 (IS-11)     -43.1  0.0
 03040A  USA 170                 -42.5  7.5
 14004A  TDRS 12                 -41.0  3.8
 13026A  SES-6                   -40.6  0.1
 13011A  SBIRS GEO-2 (USA 241)   -38.1  2.0
 09009A  TELSTAR 11N             -37.6  0.0
 05003A  NSS-10 (AMC-12)         -37.5  2.9
 17006A  HISPASAT 36W-1          -36.1  0.0
 17041A  INTELSAT 35E (IS-35E)   -34.6  0.0
 18033B  HYLAS 4                 -33.6  0.1
 08034A  INTELSAT 25 (IS-25)     -31.6  0.0
 06007A  SPAINSAT                -30.1  0.1
 10070A  HISPASAT 30W-5          -30.1  0.0
 18023A  HISPASAT 30W-6          -30.0  0.0
 02007A  INTELSAT 904 (IS-904)   -29.6  3.4
 01024A  INTELSAT 901 (IS-901)   -27.6  0.0
 19067B  MEV-1                   -27.6  0.0
 17078A  ALCOMSAT 1              -24.9  0.0
 02027A  INTELSAT 905 (IS-905)   -24.5  3.2
 99063A  UFO 10 (USA 146)        -22.9  8.8
 12007A  SES-4                   -22.1  0.0
 18012A  AL YAH 3                -20.2  0.1
 02019A  NSS-7                   -20.0  6.0
 17059A  INTELSAT 37E (IS-37E)   -18.1  0.0
 08030A  SKYNET 5C               -17.9  0.2
 12061A  LUCH 5B                 -16.3  7.4
 15002A  MUOS-3                  -15.5  2.6
 15068A  TELSTAR 12V             -15.1  0.0
 15074A  ELEKTRO-L 2             -14.5  3.1
 15048A  EXPRESS-AM8             -14.1  0.0
 22006A  USA 324                 -12.9  0.2
 08065B  EUTELSAT 48D            -12.6  1.6
 17016A  WGS F9 (USA 275)        -12.1  0.0
 17047A  TDRS 13                 -11.5  4.4
 08003A  EXPRESS-AM33            -11.2  1.2
 09007A  EXPRESS-AM44            -11.1  0.0
 03020A  HELLAS-SAT 2            -10.1  3.8
 02006A  ECHOSTAR 7               -8.2  0.4
 15039B  EUTELSAT 8 WEST B        -8.1  0.1
 11051A  EUTELSAT 7 WEST A        -7.4  0.1
 10037A  NILESAT 201              -7.1  0.0
 22006B  USA 325                  -6.9  0.1
 06033B  SYRACUSE 3B              -5.3  0.0
 02035A  EUTELSAT 5 WEST A        -5.1  2.5
 19067A  EUTELSAT 5 WEST B        -5.1  0.1
 08022A  AMOS-3                   -4.2  0.0
 14046A  ASIASAT 8 (AMOS-7)       -4.0  0.0
 14058A  LUCH (OLYMP)             -3.8  0.0
 15010A  ABS-3A                   -3.1  0.0
 07063B  HORIZONS-2               -1.6  0.0
 99009B  SKYNET 4E                -1.3 11.3
 04022A  INTELSAT 10-02           -1.1  0.0
 20056B  MEV-2                    -1.0  0.0
 09058B  THOR 6                   -0.9  0.0
 08006A  THOR 5                   -0.8  0.0
 15022A  THOR 7                   -0.7  0.0
 15034A  METEOSAT-11 (MSG-4)      -0.3  0.4
 17038A  BULGARIASAT-1             1.8  0.0
 10037B  RASCOM-QAF 1R             2.8  0.0
 14030A  EUTELSAT 3B               3.0  0.1
 10039A  AEHF-1 (USA 214)          4.1  4.7
 07057A  ASTRA 4A (SIRIUS 4)       4.7  0.0
 12036A  SES-5                     4.9  0.1
 07046A  WGS F1 (USA 195)          5.9  0.0
 13022A  EUTELSAT 7B               6.9  0.1
 19034B  EUTELSAT 7C               6.9  0.1
 20005B  EUTELSAT KONNECT          7.1  0.1
 16005A  EUTELSAT 9B               8.9  0.0
 10069A  EUTELSAT KA-SAT 9A        8.9  0.1
 12035B  METEOSAT-10 (MSG-3)       9.1  1.6
 96070A  INMARSAT 3-F3             9.6  7.3
 09016A  EUTELSAT 10A             10.0  0.0
 17032A  ECHOSTAR 21              10.2  3.9
 19080B  INMARSAT GX5             11.0  0.0
 19048A  COSMOS 2539              11.9  0.0
 06032A  EUTELSAT HOTBIRD 13B     12.9  0.1
 08065A  EUTELSAT HOTBIRD 13C     12.9  0.1
 06007B  EUTELSAT HOTBIRD 13E     12.9  0.0
 10021B  COMSATBW-2               13.1  0.0
 11057A  EUTELSAT 16A             15.9  0.1
 21063A  TIANLIAN 1-05            16.7  2.0
 21129A  SHIYAN 12 01 (SY-12 01)  16.8  0.1
 19050A  AMOS-17                  16.9  0.0
 08011A  AMC-14                   17.4 22.2
 02001A  USA 164 (MILSTAR-2 3)    19.0  9.6
 07016A  ASTRA 1L                 19.1  0.1
 11041A  ASTRA 1N                 19.1  0.0
 06012A  ASTRA 1KR                19.1  0.1
 08057A  ASTRA 1M                 19.2  0.0
 97076A  ASTRA 1G                 19.3  6.4
 11049B  ARABSAT-5C               19.9  0.1
 12040A  TIANLIAN 1-03            20.4  2.2
 21042A  SBIRS GEO-5 (USA 315)    20.8  7.3
 12062B  EUTELSAT 21B             21.5  0.1
 10021A  ASTRA 3B                 23.4  0.1
 00081A  ASTRA 2D                 23.6  7.4
 13038A  ALPHASAT                 24.8  2.7
 07056B  SKYNET 5B                25.1  1.7
 13044A  ES'HAIL 1                25.5  0.1
 18090A  ES'HAIL 2                25.7  0.0
 10025A  BADR-5                   25.9  0.0
 08034B  BADR-6                   25.9  0.1
 15065B  BADR-7 (ARABSAT-6B)      25.9  0.0
 06051A  BADR-4                   25.9  0.0
 12051A  ASTRA 2F                 28.1  0.1
 14089A  ASTRA 2G                 28.1  0.0
 13056A  ASTRA 2E                 28.4  0.1
 93056A  UFO 2 (USA 95)           28.8 11.5
 05005A  XTAR-EUR                 28.9  0.7
 10032B  ARABSAT-5A               30.4  0.1
 19021A  ARABSAT-6A               30.5  0.0
 21001A  TURKSAT 5A               30.9  0.0
 12043B  HYLAS 2                  31.0  0.0
 19049A  EDRS-C                   31.1  0.1
 14011B  ASTRA 5B                 31.4  0.0
 16015A  IRNSS-1F                 32.5  2.3
 11016A  INTELSAT NEW DAWN        32.7  0.0
 05030A  GALAXY 14 (G-14)         32.8  1.4
 09008B  EUTELSAT 33E             33.0  0.1
 19097A  SHIJIAN-20 (SJ-20)       33.4  1.3
 90079A  SKYNET 4C                33.4 13.8
 13062A  RADUGA-1M 3              34.9  2.4
 19080A  TIBA-1                   35.4  0.1
 09065A  EUTELSAT 36B             35.8  0.1
 15082A  EXPRESS-AMU1             36.0  0.0
 14006B  ATHENA-FIDUS             37.7  0.0
 11042A  PAKSAT-1R                37.9  0.0
 17040A  HELLAS-SAT 3             38.9  0.1
 19007A  HELLAS-SAT 4 & SGS-1     38.9  0.1
 15012A  EXPRESS-AM7              39.9  0.0
 02040B  METEOSAT-8 (MSG-1)       41.4  8.1
 08030B  TURKSAT 3A               41.9  0.0
 21126A  TURKSAT 5B               41.9  0.1
 14007A  TURKSAT 4A               41.9  0.1
 11077A  NIGCOMSAT 1R             42.4  0.0
 03026A  THURAYA-2                44.0  6.8
 17046A  COSMOS 2520              45.0  0.0
 18074A  AZERSPACE 2 (IS-38)      45.0  0.0
 21095B  SYRACUSE 4A              45.4  0.0
 05049B  METEOSAT-9 (MSG-2)       45.7  6.2
 13006B  AZERSPACE 1              45.9  0.0
 05041B  SYRACUSE 3A              47.0  1.3
 12016A  YAHSAT 1B                47.5  0.0
 21069B  EUTELSAT QUANTUM         47.7  0.0
 19007B  GSAT-31                  47.8  0.1
 17031A  GSAT-19                  47.8  0.1
 11034A  GSAT-12                  47.9  1.5
 19031A  YAMAL 601                48.9  0.0
 15060A  TURKSAT 4B               49.9  0.0
 16001A  BELINTERSAT-1            51.5  0.0
 15023A  TURKMENALEM52E/MONACOSA  51.9  0.0
 11016B  YAHSAT 1A                52.4  0.0
 12075A  SKYNET 5D                52.7  0.1
 14064A  EXPRESS-AM6              52.9  0.0
 19051A  AEHF-5 (USA 292)         54.4  4.2
 12070A  YAMAL 402                54.8  0.0
 13034A  IRNSS-1A                 54.9 32.6
 18089A  GSAT-29                  55.0  0.1
 14078A  GSAT-16                  55.0  0.1
 14017A  IRNSS-1B                 55.0 28.6
 11022A  GSAT-8                   55.0  0.0
 18035A  IRNSS-1I                 55.0 29.2
 14010A  EXPRESS-AT1              55.9  0.0
 17025A  INMARSAT 5-F4            56.4  0.0
 09058A  NSS-12                   56.9  0.0
 98050A  ASTRA 2A                 57.1  3.6
 09017A  WGS F2 (USA 204)         57.5  0.0
 14023B  KAZSAT-3                 58.4  0.0
 12008A  BEIDOU 11                58.7  1.7
 16053B  INTELSAT 33E (IS-33E)    59.9  0.0
 19014A  WGS 10 (USA 291)         60.3  0.0
 16052B  USA 271                  60.9  0.6
 04007A  ABS-4 (MOBISAT-1)        60.9  2.5
 06018A  EWS-G1 (GOES 13)         61.3  0.7
 19049B  INTELSAT 39 (IS-39)      61.9  0.0
 13073A  INMARSAT 5-F1            62.5  0.0
 18105A  GSAT-7A                  62.7  0.1
 09054B  COMSATBW-1               62.9  0.1
 05044A  INMARSAT 4-F2            63.8  3.5
 02041A  INTELSAT 906 (IS-906)    64.1  2.2
 13045A  AMOS-4                   64.9  0.0
 10065B  INTELSAT 17 (IS-17)      65.9  0.0
 97026A  GALAXY 25 (G-25)         66.1  3.8
 11019A  SBIRS GEO-1 (USA 230)    66.1  2.0
 17001A  TJS-2                    66.4  0.3
 16053A  INTELSAT 36 (IS-36)      68.4  0.0
 12043A  INTELSAT 20 (IS-20)      68.4  0.0
 18107A  COSMOS 2533              69.9  0.0
 18110A  TJS-3                    70.2  0.0
 12069A  EUTELSAT 70B             70.4  0.1
 89077A  FLTSATCOM 8 (USA 46)     71.9 12.8
 12011A  INTELSAT 22 (IS-22)      72.0  0.0
 18100B  GSAT-11                  73.9  0.1
 16060A  GSAT-18                  73.9  0.0
 14001A  GSAT-14                  73.9  0.0
 13044B  GSAT-7                   73.9  0.0
 16054A  INSAT-3DR                74.0  0.1
 03057A  UFO 11 (USA 174)         74.4  7.1
 16038A  ABS-2A (MONGOLSAT-1)     74.6  0.0
 14006A  ABS-2                    74.8  0.0
 15044A  MUOS-4                   75.0  2.6
 19095A  ELEKTRO-L 3              76.0  0.1
 12013A  APSTAR 7                 76.4  0.0
 09068A  WGS F3 (USA 211)         78.0  0.2
 14002A  THAICOM 6                78.4  0.0
 16031A  THAICOM 8                78.5  0.1
 18050A  FENGYUN 2H               79.1  1.3
 20053B  EXPRESS 80               80.0  0.0
 19017A  TIANLIAN 2-01            80.0  0.1
 20017A  BEIDOU-3 G2              80.0  2.0
 15075A  COSMOS 2513              80.2  0.0
 15073A  CHINASAT 1C (ZX 1C)      81.3  3.5
 21003A  TIANTONG-1 3             81.5  4.3
 13038B  INSAT-3D                 82.1  0.1
 15041A  GSAT-6                   82.5  0.1
 20099A  CMS-01                   82.9  0.1
 20005A  GSAT-30                  82.9  0.0
 12051B  GSAT-10                  83.0  0.0
 14061A  IRNSS-1C                 83.0  3.1
 19070A  TJS-4                    83.5  0.0
 12059A  BEIDOU 16                84.0  2.1
 95035B  TDRS 7                   84.8 14.0
 10002A  RADUGA-1M 2              84.9  0.0
 09067A  INTELSAT 15 (IS-15)      85.1  0.0
 11035B  KAZSAT-2                 86.4  0.0
 08066A  FENGYUN 2E               86.6  6.0
 04004A  USA 176 (DSP 22)         87.3 10.2
 12067A  CHINASAT 12 (ZX 12)      87.4  0.0
 11022B  ST-2                     87.9  0.0
 12003A  WGS F4 (USA 233)         88.3  0.0
 00034A  TDRS 8                   89.2 10.5
 14082A  YAMAL 401                89.9  0.0
 20089A  LUCAS (JDRS-1)           90.7  0.0
 14054B  MEASAT-3B                91.4  0.0
 09032A  MEASAT-3A                91.4  0.1
 08028A  CHINASAT 9 (ZX 9)        92.1  0.0
 16050A  JCSAT-16                 92.9  0.0
 17040B  GSAT-17                  93.4  0.1
 15065A  GSAT-15                  93.4  0.0
 14023A  LUCH 5V                  94.6  1.6
 18049A  SES-12                   94.9  0.0
 13071A  SES-8                    94.9  0.1
 07007B  SKYNET 5A                95.1  2.0
 15019A  BEIDOU 17                95.2 51.8
 11038A  BEIDOU 9                 95.4 54.5
 11073A  BEIDOU 10                95.9 50.2
 16021A  BEIDOU IGSO-6            95.9 58.2
 15053A  BEIDOU 20                96.4 51.4
 20053A  EXPRESS 103              96.4  0.0
 17024A  GSAT-9                   97.4  0.1
 13020A  CHINASAT 11 (ZX 11)      97.8  0.0
 21071A  CHINASAT 2E (ZX 2E)      98.0  0.1
 12028A  CHINASAT 2A (ZX 2A)      98.2  0.0
 08001A  THURAYA-3                98.4  4.1
 14090A  FENGYUN 2G               99.6  2.1
 09042A  ASIASAT 5               100.4  0.1
 21080A  CHINASAT 9B             101.3  0.1
 16048A  TIANTONG-1 1            101.3  2.3
 21123B  EXPRESS AMU-3           102.9  0.1
 16065A  SHIJIAN-17 (SJ-17)      103.1  2.2
 15063A  CHINASAT 2C (ZX 2C)     103.4  0.1
 95038A  USA 113                 103.7 12.1
 16077A  FENGYUN 4A              104.5  0.1
 00016A  ASIASTAR                104.9  5.8
 11069A  ASIASAT 7               105.4  0.0
 15083A  GAOFEN 4                105.7  0.1
 11013A  BEIDOU 8                106.9 60.4
 10068A  BEIDOU 7                107.2 50.1
 20002A  TJS-5                   107.5  0.3
 10036A  BEIDOU 5                107.7 54.2
 18064A  TELKOM 4 (MERAH PUTIH)  107.9  0.0
 09027A  SES-7 (PROTOSTAR 2)     108.2  0.0
 16013A  SES-9                   108.2  0.0
 20056A  BSAT-4B                 109.8  0.0
 17059B  BSAT-4A                 109.8  0.0
 10056B  BSAT-3B                 109.8  0.1
 07036B  BSAT-3A                 109.8  0.1
 11041B  BSAT-3C (JCSAT-110R)    109.9  0.0
 16082A  JCSAT-110A (JCSAT-15)   110.0  0.0
 17018A  CHINASAT 16 (SJ-13)     110.4  0.1
 16037A  BEIDOU-2 G7             110.4  1.5
 11026A  CHINASAT 10 (ZX 10)     110.4  0.1
 20040A  BEIDOU-3 G3             110.5  1.3
 15018A  IRNSS-1D                111.6 28.9
 16003A  IRNSS-1E                111.7 30.1
 12002A  FENGYUN 2F              112.1  3.9
 18057A  BEIDOU IGSO-7           112.6 55.1
 10064A  ZHONGXING-20A           112.8  2.8
 06034A  KOREASAT 5 (MUGUNGWHA 5 113.0  0.0
 17067A  KOREASAT 5A             113.1  0.0
 07031A  ZHONGXING-6B            115.5  0.0
 17023A  KOREASAT 7              115.8  0.0
 10070B  KOREASAT 6              115.9  0.0
 20048A  KOREASAT 116            116.1  0.0
 20071A  GAOFEN 13               117.7  0.3
 17007A  TELKOM 3S               117.9  0.0
 19023A  BEIDOU-3 IGSO-1         118.3 56.6
 19073A  BEIDOU-3 IGSO-3         118.8 57.2
 19035A  BEIDOU-3 IGSO-2         118.9 55.1
 18044A  BANGABANDHUSAT-1        119.0  0.0
 05028A  THAICOM 4               119.4  0.0
 14052A  ASIASAT 6               119.8  0.0
 17057A  ASIASAT 9               122.0  0.0
 12023A  JCSAT-13                123.9  0.0
 20082A  TIANTONG-1 2            124.8  4.0
 22038A  CHINASAT 6D             125.0  0.0
 16052A  USA 270                 126.0  0.6
 17048A  QZS-3 (MICHIBIKI-3)     127.0  0.1
 06033A  JCSAT-3A                127.9  0.0
 96053A  INMARSAT 3-F2           128.0  6.6
 18037A  COSMOS 2526             128.0  0.0
 10032A  COMS 1                  128.1  1.2
 20013B  GEO-KOMPSAT-2B          128.2  0.0
 18100A  GEO-KOMPSAT-2A          128.2  0.0
 21094A  SHIJIAN-21 (SJ-21)      128.3  8.6
 15067A  LAOSAT 1                128.4  0.0
 21096A  QZS-1R                  129.0 34.6
 16027A  IRNSS-1G                129.5  2.2
 11047A  CHINASAT 1A (ZX 1A)     129.8  0.1
 19012A  CHINASAT 6C (ZX 6C)     130.0  0.1
 19001A  CHINASAT 2D (ZX 2D)     130.0  0.0
 21114A  CHINASAT 1D (ZX 1D)     130.1  1.3
 12023B  VINASAT-2               131.8  0.0
 08018A  VINASAT-1               131.9  0.0
 06010A  JCSAT-5A                132.0  0.1
 09044A  JCSAT-12 (JCSAT-RA)     132.0  0.0
 21047A  FENGYUN 4B              133.1  0.1
 21129B  SHIYAN 12 02 (SY-12 02) 133.5  0.1
 18041A  APSTAR 6C               133.9  0.0
 20045A  APSTAR 6D               133.9  0.0
 18036A  USA 283                 134.0  0.0
 00065A  USA 153                 134.3  9.2
 20013A  JCSAT-17                135.9  6.1
 10045A  QZS-1 (MICHIBIKI-1)     136.8 42.4
 21135A  TJS-9                   137.2  0.1
 17062A  QZS-4 (MICHIBIKI-4)     137.4 40.8
 20022B  AEHF-6 (USA 298)        137.7  5.8
 18069A  TELSTAR 18V (APSTAR 5C) 137.9  0.0
 18009A  SBIRS GEO-3 (USA 282)   138.9  3.4
 14010B  EXPRESS-AT2             139.8  0.0
 13077A  EXPRESS-AM5             140.0  0.1
 18085A  BEIDOU-3 G1             140.0  1.0
 15054A  SKY MUSTER 1 (NBN1A)    140.2  0.0
 10001A  BEIDOU 3                140.4  2.0
 14060A  HIMAWARI-8              140.6  0.0
 16064A  HIMAWARI-9              140.7  0.0
 17028A  QZS-2 (MICHIBIKI-2)     141.1 41.7
 15059A  APSTAR 9                142.0  0.0
 05009A  INMARSAT 4-F1           143.5  3.7
 08038A  SUPERBIRD-C2            143.9  0.0
 19027A  BEIDOU-2 G8             144.4  1.0
 16060B  SKY MUSTER 2 (NBN1B)    144.7  0.0
 21123A  EXPRESS AMU-7           144.9  0.1
 19009A  NUSANTARA SATU          145.9  0.0
 21077A  TJS-7                   146.5  0.2
 03014A  ASIASAT 4               147.5  1.1
 16075A  WGS F8 (USA 272)        149.8  0.0
 19091A  JCSAT-18 (KACIFIC 1)    149.9  0.0
 16039A  BRISAT                  150.4  0.0
 07044A  OPTUS D2                151.9  0.1
 03012A  USA 169 (MILSTAR-2 4)   152.1 10.2
 16028A  JCSAT-2B                153.9  0.0
 15046A  TJS-1                   154.9  0.0
 03028B  OPTUS C1                155.6  3.4
 09044B  OPTUS D3                155.9  0.0
 14054A  OPTUS 10                155.9  0.0
 00072A  INTELSAT 1R (IS-1R)     157.0  4.6
 21118B  LDPE-1                  157.9  0.5
 99053A  ABS-6                   159.0  0.1
 06043B  OPTUS D1                159.9  0.1
 10057A  BEIDOU 6                160.0  1.0
 18033A  SUPERBIRD-B3            161.9  0.0
 03053A  YAMAL 202               163.4  2.8
 12030A  INTELSAT 19 (IS-19)     165.9  0.0
 97046A  INTELSAT 5 (IS-5)       166.1  7.4
 11074B  LUCH 5A                 166.9  5.2
 11032A  TIANLIAN 1-02           166.9  2.5
 18074B  HORIZONS-3E             168.9  0.0
 21124A  TIANLIAN 2-02           171.0  2.4
 17029B  EUTELSAT 172B           171.9  0.0
 95003A  UFO 4 (USA 108)         172.2  9.8
 05052A  EUTELSAT 174A           173.9  0.7
 15036A  WGS F7 (USA 263)        174.9  0.0
 00059A  NSS-11 (AAP-1)          175.9  0.1
 16072A  TIANLIAN 1-04           176.8  0.2
 98016A  UFO 8 (USA 138)         177.0  9.5
 01019A  INTELSAT 10 (IS-10)     177.7  5.7
 21010A  TJS-6                   178.6  0.5
 15042A  INMARSAT 5-F3           179.5  0.0
 11056A  INTELSAT 18 (IS-18)     179.9  0.0

Congrats, if you made it this far, you must be a space geek!

Concerning the art of prediction, Clarke formulated the following three laws:

  1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
  2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
  3. Any sufficiently advanced technology is indistinguishable from magic.

It may be said that the legacy of Sir Arthur C. Clarke is to point the way for scientists and engineers toward that “magic” future.