Summary
Starlette (Satellite de taille adaptée avec réflecteurs laser pour les études de la terre,[1][2] or lit. 'Satellite of suitable size with laser reflectors for studies of the earth') and Stella are nearly identical French geodetic and geophysical satellites. Starlette was launched on 6 February 1975 and Stella on 26 September 1993. Starlette was the first passive laser satellite developed.
| Names | Satellite de taille adaptée avec réflecteurs laser pour les études de la terre |
|---|---|
| Mission type | Scientific |
| Operator | CNES |
| Harvard designation | 1975-010A |
| COSPAR ID | 1975-010A |
| SATCAT no. | 7646 |
| Mission duration | Elasped: 49 years, 2 months and 4 days |
| Spacecraft properties | |
| Manufacturer | CNES |
| Launch mass | 47 kg (104 lb) |
| Start of mission | |
| Launch date | 6 February 1975, 16:35 UTC |
| Rocket | Diamant BP4 |
| Launch site | Guiana Space Centre |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.0206[1] |
| Perigee altitude | 812 km (505 mi) |
| Apogee altitude | 1,114 km (692 mi) |
| Inclination | 49.83 degrees |
| Period | 104 minutes |
| Mission type | Scientific |
|---|---|
| Operator | CNES |
| Harvard designation | 1993-061B |
| COSPAR ID | 1993-061B |
| SATCAT no. | 22824 |
| Mission duration | Elasped: 30 years, 6 months and 16 days |
| Spacecraft properties | |
| Manufacturer | CNES |
| Launch mass | 48 kg (106 lb) |
| Start of mission | |
| Launch date | 26 September 1993, 01:45:00 UTC |
| Rocket | Ariane 4 |
| Launch site | Guiana Space Centre |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.0206[1] |
| Perigee altitude | 804 km (500 mi) |
| Apogee altitude | 812 km (505 mi) |
| Inclination | 98.68 degrees |
| Period | 101 minutes |
Background edit
Starlette's development dates back to at least 1972, when scientists at the Centre national d'études spatiales (CNES) were trying to determine a payload for the upcoming first flight of the new Diamant BP4 rocket.[3] After consulting with the Smithsonian Astrophysical Observatory, CNES scientists decided to create a small geodetic satellite optimized for tracking by laser ranging.[3] The project was approved within a few months after a feasibility study by the French atomic agency CEA determined the dense uranium core could be made nearly non-radioactive by using depleted uranium.[3][4]
The Groupe de recherches en géodésie spatiale (GRGS; Space Geodesy Research Group) first proposed Stella to provide coverage for areas missed by Starlette.[5]
Spacecraft design edit
Starlette and Stella are nearly identical, small spherical spacecraft measuring 24 centimetres (9.4 in) in diameter.[2] With masses of 47 kilograms (104 lb) and 48 kilograms (106 lb) respectively, the satellites are quite dense.[2] This high-density spherical design reduced the drag effect of aerobraking on the satellites as they exited Earth's atmosphere. Both satellites are covered in 60 laser retroreflectors.[1][2]
Mission and results edit
Starlette was launched on 6 February 1975 at 16:35 UTC[6] by a Diamant BP4 rocket from the B launch pad at the Guiana Space Centre in Korou, French Guiana.[1][2][7] It was the first flight of a Diamant BP4 launch vehicle.[1][3]
Stella was launched on 26 September 1993 at 01:45:00 UTC[6] by an Ariane 4 (Ariane 40 H-10) rocket from the ELA-2 launch pad at the Guiana Space Centre as part of a payload also containing the satellites SPOT-3, KITSAT-2, Itamsat, Eyesat-1, PoSAT-1, and Healthsat-2.[1][2][8] The payload was located in the top part of the Ariane rocket's third stage.[1]
In the 1980s, data gathered by Starlette was used to develop a model of global ocean tides.
Legacy and status edit
Starlette was the first passive laser satellite developed.[3] The first of two American geodetic satellites called LAGEOS followed not long after in 1976.[3]
Both satellites were in orbit as of 2023.[1] They are expected to remain in orbit up to 2000 years and to remain trackable for many decades or centuries.[3][5]
See also edit
References edit
- ^ a b c d e f g h i Kramer, Herbert J. (2002). Observation of the Earth and its Environment: Survey of Missions and Sensors (4th ed.). Berlin: Springer Verlag. ISBN 3-540-42388-5. Retrieved 18 March 2021.
- ^ a b c d e f Krebs, Gunther. "Starlette / Stella". Gunther's Space Page. Retrieved 18 March 2021.
- ^ a b c d e f g Barlier, François; Lefebvre, Michel (2001). "A new look at planet Earth: Satellite geodesy and geosciences". In Bleeker, Johan A. M.; Geiss, Johannes; Huber, Martin C. E. (eds.). The Century of Space Science (PDF). Netherlands: Kluwer Academic Publishers. pp. 1623–1651. ISBN 978-94-010-0320-9. Retrieved 18 March 2021.
- ^ ILRS. "Starlette and Stella". Current Missions. International Association of Geodesy. Retrieved 3 July 2021.
- ^ a b "STELLA - The centimetre over centuries". Small Satellites Home Page (SSHP). 1995. Archived from the original on 28 April 2013.
- ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Report. Retrieved 18 March 2021.
- ^ Wade, Mark. "Starlette". Astronautix. Archived from the original on December 21, 2016. Retrieved 18 March 2021.
- ^ Wade, Mark. "STELLA". Astronautix. Archived from the original on December 28, 2016. Retrieved 18 March 2021.