Phobos and Mars 96, 1988-1996

After a long run of very successful Venus missions beginning in 1967. including the highly successful Vega mission in 1985, and the clear lack of American follow-up to the Viking Mars orbiter/landers, the Soviets took the opportunity in the late 1980s to resume Mars missions. A new Universal Mars Venus Luna (UMVL) spacecraft was developed based on the highly successful Fro ton-launched Venera series. Two such spacecraft were built for the 1988 Mars opportunity, for a mission that would focus on the Martian moon Phobos. Once a spacecraft was in orbit around the planet, it would make a series of close encounters with Phobos, coming ever closer. When the geometry was just right, active remote sensing experiments would blast material off the surface of Phobos and two small landers would be deployed, one stationary and the other mobile. It was to be a very ambitious mission, including instruments from many international partners.

The Phobos 1 spacecraft w? as lost to a command error during the interplanetary cruise. Its partner achieved Mars orbit and returned very useful remote sensing data on Mars as it trimmed its orbit to approach Phobos. Unfortunately, communica­tions with Phobos 2 w^ere lost just days before its first planned rendezvous, and only very limited remote sensing data on this target were transmitted.

Encouraged by the Phobos effort, a Mars orbiter and ambitious surface mission w’as planned. This w’as originally scheduled for launch in 1992 using a new’ version of the IJM VL spacecraft but budget constraints led to it being descoped and slipped to

1994, and then further delayed to 1996. In addition to a large orbital science payload, the orbitcr had two small soft-landers similar to the previous Mars landers and two penetrators. This project involved even more international cooperation than the Phobos effort. However, this time only a single spacecraft wras built, and when it was launched on November 16, 1996. failures in the control system between the spacecraft and the Block D upper stage resulted in the escape burn causing re-entry. Having lost Mars-96 so embarrassingly, the Russian planetary exploration program entered a hiatus which continued through the end of the 20th Century. It is scheduled for renewal with the planned launch of the Phobos-Grunt sample return spacecraft in late 2011.