Faced with tight budgets and uncertainty over new missions, space experts are learning to squeeze as much scientific data as possible from current projects. This means continuing to operate space probes beyond their expected termination dates, and finding uses for spacecraft beyond what was originally planned. For example:

• Lunar Prospector, a probe designed to orbit the moon, was crashed deliberately near the lunar South Pole on July 31. The probe was destined to crash somewhere on the moon. But aiming it at a permanently shadowed region allowed new research into whether there's ice on the moon. (Astronomers are now analyzing the impact data to see if water vapor was released.)
• Deep Space 1, a probe designed to test new technologies, increasingly has functioned as a scientific mission. It recently did a flyby of asteroid Braille and is now on course for a possible 2001 rendezvous with two comets. NASA has requested that Congress provide funding to keep the probe operational.
• Pioneer 10, now almost 7 billion miles from Earth, continues to gather data long past its expected life span. The probe was the first to explore the outer planets and leave the solar system. Pioneer 10 served as a "training mission" in recent years for the (soon-to-be-disbanded) Lunar Prospector team, and the old probe may continue to operate as controllers check in on it in their spare time.
• The Wide Field Infrared Explorer (WIRE), an orbiting observatory, was considered a total loss because its telescope was damaged shortly after the spacecraft's launch in March. But astronomers are now gathering scientific data with WIRE's "star camera," a smaller telescope whose original function was to keep the spacecraft pointed in the correct direction.
• The Voyager space probes completed their primary mission -- flybys of the outer planets -- a decade ago, and are now embarked on the Voyager Interstellar Mission, which will bring them past the outer reaches of the sun's influence. Both Voyager 1 and Voyager 2 have adequate electrical power to continue gathering data until around 2020.
• The Galileo spacecraft, which is orbiting Jupiter and its moons, is nearing the end of a 2-year extension of its mission, and may continue operating beyond that. The probe will conduct flybys of the volcanic moon Io in October and November, and might perform joint observations with the Cassini space probe when the latter passes Jupiter late next year.

There will, doubtless, be more examples of this kind of "mission recycling" in the future. You can keep track of these and other missions by using space.com's Exploratory Missions database.