View source for PAS-22

{{Short description|PanAmSat communications satellite}}
{{Use American English|date=May 2021}}
{{Use dmy dates|date=May 2021}}
{{Infobox spaceflight
| name              = AsiaSat 3 → HGS-1 → PAS-22
| names_list        = AsiaSat 3<br/>HGS-1<br/>PAS-22
| image             = Asiasat-3.gif
| image_caption     = 
| image_size        = 300px

| mission_type      = [[Communications satellite|Communications]]
| operator          = [[AsiaSat]] (1997–1998)<br/>[[Hughes Space and Communications|Hughes]] (1998–1999)<br/>[[PanAmSat]] (1999–2002)
| COSPAR_ID         = 1997-086A 
| SATCAT            = 25126
| mission_duration  = 15 years (planned) <ref>{{cite web|url=http://space.skyrocket.de/doc_sdat/asiasat-3.htm|title=AsiaSat-3, -3S / HGS-1 / PAS-22|publisher=Gunter's Space Page|access-date=15 May 2010}}</ref>
<br/>4 years (achieved)

| spacecraft        = AsiaSat 3
| spacecraft_type   = [[Boeing 601]]
| spacecraft_bus    = [[Boeing 601|HS-601HP]]
| manufacturer      = [[Hughes Space and Communications]]
| launch_mass       = 3,465 kg<ref>{{cite web|url=https://solarsystem.nasa.gov/missions/asiasat-3-hgs-1/in-depth/ |title=AsiaSat 3 → HGS-1 → PAS-22 |publisher=NASA's Solar System Exploration website |access-date=December 1, 2022}}</ref>
| dry_mass          = {{cvt|2500|kg}}
| dimensions        = 3.4 m x 3.5 m x 5.8 m<br/>Span: 26.2 m on orbit
| power             = 9.9 [[Watt|kW]]

| launch_date       = 24 December 1997,<br/>23:19:00 [[Coordinated Universal Time|UTC]]<ref>{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|publisher=Jonathan's Space Report |date=14 March 2021|access-date=3 May 2021}}</ref>
| launch_rocket     = [[Proton-K]] / [[Blok D|DM-2M]]
| launch_site       = [[Baikonur Cosmodrome|Baikonur]], [[Baikonur Cosmodrome Site 81|Site 81/23]]
| launch_contractor = [[Khrunichev State Research and Production Space Center]]

| entered_service   = July 1998
| disposal_type     = [[Graveyard orbit]]
| deactivated       = July 2002
| last_contact      =

| orbit_reference   = [[Geocentric orbit]]
| orbit_regime      = [[Geostationary orbit]]
| orbit_longitude   = 105.5° East (intended)<br/>158° West (1998-1999)<br/>62° West (1999–2002) <ref name="TSE"/>
| apsis             = gee

|interplanetary     = 
 {{Infobox spaceflight/IP
   | type           = flyby
   | object         = [[Moon]]
   | arrival_date   = 13 May 1998, 19:00 UTC <ref name="flybys">{{cite web|url=http://www.xs4all.nl/~carlkop/asiasat.html|title=AsiaSat 3|access-date=15 May 2010}}</ref>
   | distance       = {{cvt|6200|km}}
}} 
 {{Infobox spaceflight/IP
   | type           = flyby
   | object         = Moon
   | arrival_date   = 6 June 1998, 16:30 UTC
   | distance       = {{cvt|34300|km}}
}}

| trans_band        = 44 [[Transponder (satellite communications)|transponders]]:<br/>28 [[C band (IEEE)|C-band]]<br/>16 [[Ku band|Ku-band]]
| trans_frequency   = 
| trans_bandwidth   = 
| trans_capacity    = 
| trans_coverage    = [[Asia]]

| programme         = [[AsiaSat|AsiaSat constellation]]
| previous_mission  = [[AsiaSat 2]]
| next_mission      = [[AsiaSat 3S]]

| programme2        = [[AsiaSat|PanAmSat constellation]]
| previous_mission2 = [[PAS 6B]]
| next_mission2     = [[PAS 9]]
}}

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

== Launch of AsiaSat 3 ==
AsiaSat 3 was launched for [[AsiaSat]] of [[Hong Kong]] to provide communications and television services in Asia by a [[Proton-K]] / [[Blok D|DM-2M]] [[launch vehicle]] on 24 December 1997, destined for an orbital position at 105.5° East. However, a failure of the Blok DM-2M fourth stage left it stranded in a highly inclined (51.6°) and elliptical orbit, although still fully functional. It was declared a total loss by its insurers.

== HGS-1 ==
[[File:Animation of PAS-22 trajectory around Earth.gif|thumb|upright=1.0|left|Animation of AsiaSat 3 / HGS-1 trajectory around [[Earth]] from 24 December 1997 to 30 June 1998<br/>{{legend2|magenta|AsiaSat 3 / HGS-1}}<br/>{{legend2|Lime|[[Moon]]}}<br/>{{legend2|RoyalBlue|[[Earth]]}}]]

The satellite was transferred to Hughes Global Services Inc., which was then a subsidiary of [[Hughes Aircraft Company#Hughes Space and Communications Group|Hughes Space and Communications]], with an agreement to share any profits with the consortium of 27 insurers.<ref name="hughes"/>

[[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 considered this trajectory concept unworkable. Instead, Hughes used an [[Apollo program|Apollo]]-style [[free-return trajectory]] that required only a few days to complete, a trajectory designed and subsequently patented <ref>Salvatore, Jeremiah O., and Ocampo Cesar A. (Assignee: Hughes Electronics Corporation) U.S. Patent 6,116,545, "Free return lunar flyby transfer method for geosynchronous satellites", Filed April 9, 1998.</ref><ref>Salvatore, Jeremiah O. and Ocampo, Cesar A. (Assignee: Hughes Electronics Corporation) U.S. Patent 6,149,103, "Free return lunar flyby transfer method for geosynchronous satellites having multiple perilune stages", filed May 15, 1998</ref> by Hughes Chief Technologist Jerry Salvatore.<ref name="Hughes1">J. Fisher, [http://www.hughesscgheritage.com/asiasat-rescue-the-real-story-part-1/ "AsiaSat Rescue: The Real Story, Part 1"] Hughes, July 8, 2013 (accessed 10 December 2014)</ref> This maneuver removed only 40° of [[orbital inclination]] and left the satellite in a [[geosynchronous]] orbit, whereas the Belbruno maneuver would have removed all 51° of inclination and left it in [[geostationary]] orbit.<ref name="hughes">{{cite web|url=http://sse.jpl.nasa.gov/news/display.cfm?News_ID=33835|title=HGS-1 Arrives in Earth Orbit: First Commercial Lunar Mission|publisher=NASA|date=17 June 1998|access-date=4 May 2021|url-status=dead|archive-url=https://web.archive.org/web/20100730230641/http://sse.jpl.nasa.gov/news/display.cfm?News_ID=33835|archive-date=30 July 2010}} {{PD-notice}}</ref>

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. According to Cesar Ocampo, Hughes had not considered this option until it was contacted by Ridenoure,<ref name="ocampo">{{cite web|url=http://www.spacedaily.com/news/Book_Reveals_How_Hughes_Saved_ComSat_In_1997.html|title=New Book Reveals How Engineers Saved Hughes Satellite on Christmas Day 1997|newspaper=Space Daily|date=11 January 2006}}</ref> although the Hughes engineers involved in the lunar flyby operations have stated that they were already working on the lunar swingby mission design before being contacted by him.<ref name="Hughes1"/>

=== Rescue of satellite ===
Using on-board propellant and lunar gravity, the orbit's [[Apsis|apogee]] was gradually increased with several manoeuvres at [[Apsis|perigee]] until it flew by the Moon <ref name="ocampo"/> at a distance of 6,200&nbsp;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 (6 June 1998) at a distance of 34,300&nbsp;km to further improve the [[orbital inclination]].<ref name="hughes"/>

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 158° West.<ref name="hughes"/>

Once the satellite was in a stable orbit, it was commanded to release its [[Solar panels on spacecraft|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 engineers attributed to heating and cooling cycles due to the satellite operating outside its design range while traveling to its final orbit.<ref name="hughes"/>

== PAS-22 ==
In April 1999, Hughes filled to request authorization to operate the satellite at 60° West in C-band and in Ku-band. In 1999, HGS-1 was acquired by [[PanAmSat]], and renamed as '''PAS-22''', and moved to 60° West. It was deactivated in July 2002 and moved to a [[graveyard orbit]].<ref name="TSE">{{cite web|url=http://www.tbs-satellite.com/tse/online/sat_asiasat_3.html|title=Asiasat 3|publisher=The Satellite Encyclopedia|access-date=15 May 2010}}</ref>

== See also ==
{{Portal|Spaceflight}}
* [[AMC-14]]

== References ==
{{Reflist|30em}}

== External links ==
* {{cite web|url=http://space.skyrocket.de/doc_sdat/asiasat-3.htm|title=AsiaSat 3, 3S / HGS 1 / PAS 22|publisher=Gunter's Space Page|date=22 March 2013|access-date=May 14, 2013}}
* {{cite web|url=http://www.thespacereview.com/article/2295/1|title=Beyond GEO, commercially: 15 years... and counting|last=Ridenoure|first=Rex|publisher=The Space Review|date=13 May 2013|access-date=May 14, 2013}}
* {{cite web|url=http://www.thespacereview.com/article/2329/1|title=The Chief Technologist's view of the HGS-1 mission|last=Salvatore|first=Jerry|publisher=The Space Review|date=15 July 2013|access-date=July 15, 2013}}
* {{cite web|url=http://www.thespacereview.com/article/2325/1|title=An alternative view of the HGS-1 salvage mission|last=Skidmore|first=Mark|publisher=The Space Review|date=8 July 2013|access-date=July 8, 2013}}
* {{cite web|url=http://www.xs4all.nl/~carlkop/asiasat.html|title=AsiaSat 3: Collection of related press releases|publisher=Astronet|access-date=May 14, 2013}}
* {{cite web|url=http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Asiasat&Display=ReadMore|title=Asiasat 3/HGS 1 Mission to Moon|publisher=NASA|date=19 December 2011|access-date=4 May 2021|archive-url=https://web.archive.org/web/20121007154147/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Asiasat&Display=ReadMore|archive-date=7 October 2012|url-status=dead}}

{{AsiaSat}}
{{Chinese satellites}}
{{Moon spacecraft}}
{{Orbital launches in 1997}}

[[Category:Satellites using the BSS-601 bus]]
[[Category:Communications satellites in geostationary orbit]]
[[Category:Missions to the Moon]]
[[Category:Satellite launch anomalies]]
[[Category:Spacecraft launched in 1997]]
[[Category:AsiaSat satellites]]
[[Category:Spacecraft launched by Proton rockets]]