Starlette and Stella
| 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 |
| 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 |
| 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 |
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.
Background
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
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
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
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 2021.[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
References
- ^ 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.