The new robotic probes will be fueled by a new generation of rockets powered by a new class of atomic powerplants that will give the spacecraft unprecedented capabilities, agency officials told United Press International.
Based on NASA's latest roadmap that supports President Bush's space exploration vision, which was unveiled on Jan. 14, the new missions will begin in 2008 with a robotic craft orbiting the moon and imaging its surface features. But the hardiest space robots under design will set sail well beyond Earth's vicinity. They will follow the Voyager and Galileo spacecraft to continue studying the frozen worlds orbiting the planet Jupiter.
In the mid 1990s, the Galileo probe found evidence that oceans of liquid water lay beneath thick sheets of ice on Europa, Callisto and Ganymede -- three of the four largest moons orbiting Jupiter.
The new probe, called the Jupiter Icy Moons Orbiter, or JiMo, will be designed to bring 21st-century instruments and technology to examine the Galilean moons -- so named because they were discovered by Italian astronomer Galileo Galilei in 1610 -- ever more deeply.
NASA's current plan calls for the JiMo mission to be launched into high Earth orbit by a new version of today's Atlas or Delta space boosters. Once in orbit, JiMo then would unfold into a spacecraft more than 100 feet long. It would carry a new type of rocket motor and a powerful new nuclear reactor that would drive the probe's experiments and, in smaller versions, perhaps smaller, separate probes launched from the mothership.
The idea behind JiMo is to flight-test new technologies that eventually would be aimed at closer targets, such as moon landings. The mission is part of the NASA's new building-block strategy for space exploration, according to NASA space architect Gary Martin.
"Mars is not a stopping point," Martin said. "Some of our studies looked at what the next location past Mars would be."
NASA identified Jupiter's Galilean moons because they, as Mars once did, may harbor liquid water. Using its new powerplant, which is being developed under an effort called Project Prometheus, JiMo would be able to visit the frozen worlds for years at a time, changing orbits at will to investigate newly discovered and interesting features located by its onboard imaging systems.
The added capabilities offered by Prometheus also would make it possible for JiMo to send down space probes that could function as mini-submersibles, plunging into and burrowing through the frozen ice fields to dive deeply into the alien oceans. The space subs then would transmit back their discoveries -- possibly including images -- to JiMo in orbit, which would relay the data back to mission controllers on Earth.
"What are some promising scientifically driven exploration locations?" Martin asked. "You can change the whole way you do science because you can circle each of the icy moons of Jupiter, but you also have the power when you are done doing the science around one (moon) you can go on to the other."
Eventually, the Prometheus system that will be test-flown aboard JiMo will be used to help power astronauts' base camps while on the moon's surface.
"These are building blocks," Martin explained.
"In due course, human explorers will follow," said Sean O'Keefe, NASA's administrator.
Depending on what the robot explorers discover on Mars, or the moons of Jupiter, O'Keefe said, "this is a stepping stone approach, and we will adjust accordingly to be adaptive and flexible in our approach."
Frank Sietzen covers aerospace developments for UPI Science News. E-mail firstname.lastname@example.org