PAS-22

PAS-22
AsiaSat 3 → HGS-1 → PAS-22
Operator Hong Kong AsiaSat (1997–1998)
United States Hughes (1998–1999)
United States PanAmSat (1999–2002)
Major contractors Hughes
ILS (LSP)
Bus HS-601HP
Mission type Communications
Flyby of The Moon:[1]
#1: 13 May 1998, 19:00 UTC
#2: 6 June 1998, 16:30 UTC
Launch date 24 December 1997
23:19 UTC[2]
Carrier rocket Proton-M/DM3
Launch site Baikonur Site 81/23
Mission duration 15 years (planned)[3]
4 years (achieved)
COSPAR ID 1997-086A
Mass 3,400 kilograms (7,500 lb)
Orbital elements
Regime Highly elliptical (1997–1998)
Geosynchronous (1998–2002)
Graveyard (2002—)
Longitude 105.5° East (intended)
158° West (1998)
62° West (1999-2002)[4]
Transponders
Transponders 28 G/H band (IEEE C band)
16 J band (IEEE Ku band)

PAS-22, previously known as AsiaSat 3 and then HGS-1, was a geosynchronous communications satellite which was salvaged from an unusable geosynchronous transfer orbit by means of the Moon's gravity.

AsiaSat 3 was launched by AsiaSat Ltd of Hong Kong to provide communications and television services in Asia by a Proton booster on 24 December 1997, destined for an orbit slot at 105.5° E. However, a failure of the Blok DM3 fourth stage left it stranded in a highly inclined (51 degrees) and elliptical orbit, although still fully functional. It was declared a total loss by its insurers. The satellite was transferred to Hughes Global Services, Inc., with an agreement to share any profits with the insurers.

Edward Belbruno and Rex Ridenoure heard about the problem and proposed a 3-5 month low energy transfer trajectory that would swing past the moon and leave the satellite in geostationary orbit around the earth. Hughes had no ability to track the satellite at such a distance, and opted instead for an Apollo-style free return trajectory that required only a few days to complete. This maneuver removed only 40 degrees of orbital inclination and left the satellite in a geosynchronous orbit, whereas the Belbruno maneuver would have removed all 51 degrees of inclination and left it in geostationary orbit. [5]

Although Hughes did not end up using the low-energy transfer trajectory, the insight to use a lunar swingby was key to the spacecraft rescue. Hughes had not considered this option until it was contacted by Ridenoure. [6]

Rescue of satellite

Using on-board propellant and lunar gravity, the orbit's apogee was gradually increased with several manoeuvres at perigee until it flew by the Moon [6] at a distance of 6,200 km from its surface in May 1998, becoming in a sense the first commercial lunar spacecraft. Another lunar fly-by was performed later that month at a distance of 34,300 km to further improve the orbital inclination.

These operations consumed most of the satellite's propellant, but still much less than it would take to remove the inclination without the Moon assist manoeuvres. With the remaining fuel, the satellite could be controlled as a geosynchronous satellite, with half the life of a normal satellite - a huge gain, considering that it had been declared a total loss. The satellite was then maneuvered to geosynchronous orbit at 150–154° W.

After the satellite was in a stable orbit, the satellite was commanded to release its solar panels which had been stowed during takeoff and maneuvering. Of the satellite's two solar panels only one released, and it became apparent that a tether was not operating correctly on board, which scientists attributed to heating and cooling cycles during the satellites operating in ranges not designed to while traveling to orbit. In 1999, HGS-1 was acquired by PanAmSat, renamed to PAS 22, and moved to 60° W. It was deactivated in July 2002, and moved to a graveyard orbit.[4]

References


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • pas — pas …   Dictionnaire des rimes

  • pas — 1. (pâ ; l s se lie : un pâ z allongé) s. m. 1°   Action de mettre un pied devant l autre pour marcher. 2°   Pas, en termes d escrime. 3°   Les premiers pas. 4°   Faux pas. 5°   Pas, en termes de danse. 6°   Pas, en termes militaires. 7°   Pas,… …   Dictionnaire de la Langue Française d'Émile Littré

  • pas — Pas, Tantost est nom m. et signifie proprement ores une enjambée ou simple, contenant deux pieds et demy, ou Geometrique contenant cinq pieds, à quatre paulmes pour pied, Passus. Duquel mot il vient par apocope. Ores improprement quelconque… …   Thresor de la langue françoyse

  • pas — pȁs m <G psȁ, V psȅ/psȕ, N mn psȉ, G pásā> DEFINICIJA 1. zool. a. domaća životinja Canis canis, Canis familiaris [lovački pas; ovčarski pas; pas lutalica; policijski pas]; ćuko b. (u raznim usporedbama) [žedan kao pas, ljut kao pas, umoran… …   Hrvatski jezični portal

  • pas — I {{/stl 13}}{{stl 8}}rz. mnż I, D. a, Mc. passie {{/stl 8}}{{stl 20}} {{/stl 20}}{{stl 12}}1. {{/stl 12}}{{stl 7}} taśma z mocnego materiału lub skóry, zapinana lub (rzadziej) wiązana na ubraniu w talii : {{/stl 7}}{{stl 10}}Wąski, szeroki,… …   Langenscheidt Polski wyjaśnień

  • PAS 78 — PAS 78: Guide to good practice in commissioning accessible websites is a Publicly Available Specification published on March 8, 2006 by the British Standards Institution (BSI) in collaboration with the Disability Rights Commission (DRC). It… …   Wikipedia

  • PAS — steht als Abkürzung steht für: Paraaminosalicylsäure, ein Medikament zum Einsatz gegen Tuberkulose Paris Air Show Partidul Alianța Socialistă, eine rumänische Partei Parti Islam Se Malaysia, islamistische Partei in Malaysia parental alienation… …   Deutsch Wikipedia

  • PAS — or Pas may refer to: Contents 1 Automotive 2 Companies 3 Medicine 4 Organizations 5 Places …   Wikipedia

  • PAS 55 — Optimal management of physical assets is a Publicly Available Specification published by the British Standards Institution. This PAS gives guidance and a 28 point requirements checklist of good practices in physical asset management; typically… …   Wikipedia

  • păs — PĂS, păsuri, s.n. Durere (sufletească) greu de suportat; suferinţă, chin; necaz, supărare; grijă; împrejurare dificilă, impas. *. loc. adv. Fără păs = nepăsător; indiferent. – lat. pensum. Trimis de valeriu, 03.02.2004. Sursa: DEX 98  PĂS s. 1.… …   Dicționar Român

  • Pas — Porté dans le département du Nord, en Belgique et aux Pays Bas (également Van der Pas, Van de Pas), c est un toponyme évoquant un passage, le plus souvent un gué. Une commune du Pas de Calais s appelle Pas. Le nom est également présent dans le… …   Noms de famille

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”