In 1996 Robert Zubrin proposed a new version of a manned Mars flyby mission, dubbed Athena. Unlike previous fly-by concepts, Athena would remain in the vicinity of Mars for a year while the crew remotely operated probes of the Martian surface and atmosphere. This would eliminate the round-trip radio time lag of ten to forty minutes in trying to operate such probes from the earth.
Athena would follow a low-energy earth-Mars trajectory. At Mars encounter the planet's gravity would be used to change the spacecraft's orbit to one similar to but inclined 9.5 degrees from that of Mars. The spacecraft would spend a year 'shadowing' the planet and operating four remote-controlled rovers delivered separately to the surface. At the end of that period Athena's orbit would again bring it to Mars. The flyby would send it on a slow nine month trajectory back towards earth. On approach to earth the crew would an ISS ACRV-derived re-entry vehicle to renter the earth's atmosphere. The 2.5 year mission would finish with splashdown in the ocean for recovery by the US Navy.
Athena would have a crew of two. The spacecraft and its trans-Mars injection stage would be assembled in low earth orbit using two shuttle launches and four Proton launches. The Mars probes (four rovers) would be launched separately by Delta 7925 or Molniya launch vehicles. Other possible probes would include subsonic remotely piloted drones or controlled balloons equipped with imaging systems and deployable/recoverable rovers.
The Athena spacecraft would be 5 m in diameter and 15 m long. It would be spun to generate artificial gravity, with fixed solar panels generating 5 to 10 kilowatts of power. Total mass would be 25.9 tonnes, broken down as follows:
Three mission trajectories were calculated:
The total estimated cost of $ 2.148 billion broke down as follows:
Zubrin advocated Athena as an 'icebreaker' mission - a quick and cheap way to demonstrate once and for all the possibility of long-duration manned interplanetary flight. He contrasted this to NASA's 30 year Mars plan that would spend vast sums and time in an attempt to eliminate all risk and solve the problem of long-duration zero-gravity flight.
Unit Price $ : 500.00 million. Craft.Crew Size: 2. Design Life: 2.5 years. Total Length: 15.0 m. Maximum Diameter: 5.0 m.
Unlike previous fly-by concepts, Robert Zubrin's Athena would remain in the vicinity of Mars for a year while the crew remotely operated probes of the Martian surface and atmosphere.