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Starlette and Stella

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Starlette
NamesSatellite de taille adaptée avec réflecteurs laser pour les études de la terre
Mission typeScientific
OperatorCNES
Harvard designation1975-010A
COSPAR ID1975-010A Edit this at Wikidata
SATCAT no.7646
Mission durationElasped: 49 years, 10 months and 13 days
Spacecraft properties
ManufacturerCNES
Launch mass47 kg (104 lb)
Start of mission
Launch date6 February 1975, 16:35 (1975-02-06UTC16:35Z) UTC
RocketDiamant BP4
Launch siteGuiana Space Centre
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Eccentricity0.0206[1]
Perigee altitude812 km (505 mi)
Apogee altitude1,114 km (692 mi)
Inclination49.83 degrees
Period104 minutes
Stella
Mission typeScientific
OperatorCNES
Harvard designation1993-061B
COSPAR ID1993-061B
SATCAT no.22824
Mission durationElasped: 31 years, 2 months and 23 days
Spacecraft properties
ManufacturerCNES
Launch mass48 kg (106 lb)
Start of mission
Launch date26 September 1993, 01:45:00 (1993-09-26UTC01:45Z) UTC
RocketAriane 4
Launch siteGuiana Space Centre
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Eccentricity0.0006[2]
Perigee altitude804 km (500 mi)
Apogee altitude812 km (505 mi)
Inclination98.68 degrees
Period101 minutes

Starlette (Satellite de taille adaptée avec réflecteurs laser pour les études de la terre,[1][3] 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

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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.[4] After consulting with the Smithsonian Astrophysical Observatory, CNES scientists decided to create a small geodetic satellite optimized for tracking by laser ranging.[4] 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.[4][5]

The Groupe de recherches en géodésie spatiale (GRGS; Space Geodesy Research Group) first proposed Stella to provide coverage for areas missed by Starlette.[6]

Spacecraft design

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Starlette and Stella are nearly identical, small spherical spacecraft measuring 24 centimetres (9.4 in) in diameter.[3] With masses of 47 kilograms (104 lb) and 48 kilograms (106 lb) respectively, the satellites are quite dense.[3] 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][3]

Mission and results

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Starlette was launched on 6 February 1975 at 16:35 UTC[7] by a Diamant BP4 rocket from the B launch pad at the Guiana Space Centre in Korou, French Guiana.[1][3][8] It was the first flight of a Diamant BP4 launch vehicle.[1][4]

Stella was launched on 26 September 1993 at 01:45:00 UTC[7] 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][3][9] 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

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Starlette was the first passive laser satellite developed.[4] The first of two American geodetic satellites called LAGEOS followed not long after in 1976.[4]

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.[4][6]

See also

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References

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  1. ^ a b c d e f g h 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.
  2. ^ "Stella TLE". n2yo.com. Retrieved 2024-06-07.
  3. ^ a b c d e f Krebs, Gunther. "Starlette / Stella". Gunther's Space Page. Retrieved 18 March 2021.
  4. ^ 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.
  5. ^ ILRS. "Starlette and Stella". Current Missions. International Association of Geodesy. Retrieved 3 July 2021.
  6. ^ a b "STELLA - The centimetre over centuries". Small Satellites Home Page (SSHP). 1995. Archived from the original on 28 April 2013.
  7. ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Report. Retrieved 18 March 2021.
  8. ^ Wade, Mark. "Starlette". Astronautix. Archived from the original on December 21, 2016. Retrieved 18 March 2021.
  9. ^ Wade, Mark. "STELLA". Astronautix. Archived from the original on December 28, 2016. Retrieved 18 March 2021.