Asiasat 3 / HGS-1
This lunar flyby was a clever rescue operation to fix the orbit of a stranded commercial communications satellite.It was the first commercial spacecraft to reach the vicinity of the Moon.
| Nation | None (Private Company) |
| Objective(s) | Geostationary Orbit, Circumlunar Mission |
| Spacecraft | Asiasat 1 |
| Spacecraft Mass | 7,640 pounds (3,465 kilograms) |
| Mission Design and Management | Asiasat (Operator) + Hughes (Design and Manufacture) |
| Launch Vehicle | Proton-K + Blok DM3 (8K82K no. 394-01 / Blok DM3 no. 5L) |
| Launch Date and Time | Dec. 24,1997 / 23:19 UT |
| Launch Site | Baikonur Cosmodrome, Kazakhstan |
| Scientific Instruments | None |
Firsts
This was the first commercial spacecraft to reach the vicinity of the Moon.
Results
The lunar flyby accomplished by Asiasat 3 was not part of a science mission but rather the end result of a rescue mission of a satellite that had been stranded in an incorrect orbit.
Asiasat 3 was a communications satellite, based on the Hughes HS-601HP bus, launched by the Russians for Asia Satellite Telecommunications Company (AsiaSat).
Because of the improper second firing of the Blok DM3 upper stage, the satellite ended up in a useless 125 x 22,370-mile (203 × 36,000-kilometer) orbit around the Earth and was written off as a loss by AsiaSat.
Insurance underwriters subsequently signed an agreement with Hughes Global Systems who built the satellite to salvage the vehicle and bring it to its originally intended geostationary orbit by using as little propellant as possible.
Using 11 carefully planned burns beginning April 12, 1998, controllers raised the orbit’s apogee to 199,460 miles (321,000 kilometers). Then, with the 12th firing on May 7, 1998, the spacecraft was sent on a nine-day round trip around the Moon, approaching as close as about 3,850 miles (6,200 kilometers) to the surface on May 13.
Using this gravity assist, Asiasat 3 hurled back into a usable orbit. By May 16, 1998, perigee had been raised to about 26,000 miles (42,000 kilometers) and the inclination reduced from 51 degrees to 18 degrees.
A second circumlunar mission began June 1 that culminated in a 21,300-mile (34,300-kilometer) flyby of the Moon on June 6, a distance closer than the Soviet Luna 3.
After four more engine firings, the satellite was finally in a 24-hour geosynchronous orbit by June 17, 1998, above 153 degrees.
The satellite, now owned by Hughes, was renamed HGS 1. In 1999, HGS-1 was bought by PanAmSat and renamed PAS 22 and moved to 60 degrees west longitude. In July 2002, it was deactivated and moved to a graveyard orbit.
Source
Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.
