THIS is the year of the Red Planet. Three robot spacecraft - two American, one Russian - are on track for autumn launches to begin a new era of intensified Mars exploration, studying everything from the soil and air to the weather.
The National Aeronautics and Space Administration (NASA) has even chosen to portray its coming missions to Mars as a search for extraterrestrial life, which the agency now calls the focus of future planetary exploration.
If nothing else, NASA hopes 1996 will bring a quick recovery from the embarrassing loss of the $790 million Mars Observer, which fell silent Aug. 21, 1993, three days before entering Martian orbit. As Congress continues cutting budgets this year, NASA officials are taking pains to cite their own cost-cutting zeal. They point to the Mars Surveyor program, scheduled to launch six of Mars Observer's eight instruments this November and to enter Martian orbit in September 1997, which costs a "mere" $154 million.
The 10-year Mars Surveyor program will have an American accent for a while, as it sends both an orbiter and a landing craft every time Earth and Mars are favorably aligned for the voyage. Those opportunities occur in 1996, 1998, 2001, 2003, and 2005. Yet NASA hopes other nations will join the fun either as partners in joint missions or with missions of their own - as in the case of Russia's Mars '96 venture.
"International participation, collaboration, and coordination will be a cornerstone of all new missions to Mars," according to the California Institute of Technology's Jet Propulsion Laboratory (JPL), which manages NASA's Mars programs from Pasadena, Calif.
THE final form of this collaboration is uncertain. The grand vision of a "Mars Together" partnership between Russia and the United States is dimmed by Russia's ongoing financial crisis. Russia had planned missions for both 1994 and '96 launch opportunities, but budget woes forced it to cancel the original '96 mission and delay the '94 plans for two years. Now the Russian Space Agency is struggling to keep that delayed mission on schedule for a November '96 launch. It involves a spacecraft that will send two soil penetrators and two small landers to the surface as it orbits Mars.
Russia also has postponed future "Mars Together" missions until the next century. Instead, Russia is supplying hardware and a co-investigator for an infrared radiometer to measure temperature, water vapor, and dust in the Martian atmosphere, which will fly on NASA's Mars Surveyor '98 orbiter.
For its part, the 14-member European Space Agency is considering a joint project with NASA for the 2003 launch opportunity. This could place an instrument network on Mars. The one firm commitment by another nation is Japan's Planet B project to send a Mars orbiter in 1998 to study upper atmospheric physics.
Meanwhile, NASA is pressing on with its own ambitious program, subject to continued funding support. The orbiting Global Surveyor is to provide planet-wide maps of Martian topography and mineral distribution and to monitor the weather. After completing this two-year mission, the orbiter will be available as a radio relay for future missions, partly as an inducement for future international projects.
One project, the 1996 Pathfinder lander, is not part of the Mars Surveyor program. It is scouting the way for that program's landers. But Pathfinder itself is the first of NASA's low-cost Discovery missions - the only one targeted on Mars. Low-cost means spend no more than $150 million and finish the job in three years. Pathfinder will test hardware and techniques for sending landers directly from Earth to the Martian surface. It will also release a small rover vehicle called Sojourner.
In 1998, NASA's smaller, lighter, cheaper approach fully kicks in. Both the orbiter and lander will be half the mass of the 1996 craft. They will travel into space on a new medium light launch rocket that is limited to payloads of no more than 992 pounds. The orbiter-lander pair are designed to continue exploration of Mars's climate and to search for water. The lander - the first to land in a polar region - has "a particularly interesting and exciting" mission, according to Wesley Huntress Jr., NASA's associate administrator for space science. The south polar region where it is to land is one of the areas that "probably holds the key to understanding ... climate fluctuations on the planet over thousands or even hundreds of thousands of years," he says. He adds that "the nature of the orbit of Mars makes this our only opportunity to send a mission to a pole during the next decade."
Like its predecessor, the 1996 Mars Global Surveyor, '98 orbiter will continue to operate after it has finished its primary two-year assignment, acting as a radio relay for future NASA or international missions.