Pluto mission revived -- barely
Artist's concept of the Pluto Express spacecraft near Pluto and its moon Charon
(CNN) -- NASA announced Wednesday it was reconsidering a mission
to Pluto, the only planet that has not been visited by
Earth-launched space probes. Just three months ago, the agency had said it was canceling the project.
The proposed Pluto-Kuiper Express would also fly by Pluto's moon
Charon and the Kuiper Belt, a ring of icy objects beyond the
planets that may hold clues about how the solar system formed.
Citing cost overruns and technical delays, NASA
stopped work on the mission in September. Planetary scientists immediately protested the cancellation, saying indispensable science would be lost unless a Pluto probe was launched as scheduled in 2004.
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"It is the last opportunity for the spacecraft to take advantage
of a Jupiter gravity assist to give it the boost it needs to
reach Pluto in reasonable flight times," Louis Friedman,
director of the Planetary Society, said in a statement.
Timing is critical. Pluto, which has a highly
elliptical and inclined orbit, is currently heading away from the
"A later launch pushes the arrival date so far in the future that
most of Pluto's tenuous atmosphere might freeze out by the time
the spacecraft gets there," Friedman said.
But the revived Pluto Express could easily die again. To cut costs, NASA has decided to accept outside bids to develop the project. Unless the agency finds an acceptable proposal by next autumn with a
total price under $500 million, it will drop the mission
"We are not making a commitment to doing a Pluto mission. We are
just looking at proposals," NASA Associate Administrator Ed
Weiler told reporters Wednesday.
Improved technology might allow a probe to launch later than 2004
and forgo a Jupiter gravity assist. "The arrival time at Pluto
would be a key factor, not a launch date," Weiler said.
Bids for the Pluto mission are due in March.
NASA's Jet Propulsion Laboratory will continue with current plans to develop an orbiter slated to visit Europa, an ice-encrusted moon of Jupiter. Scientists speculate that the large satellite contains a warm salty ocean, a favorable condition for the search for life.
But budget and technology constraints could prevent both the Pluto
Express and the Europa Orbiter from launching this decade,
according to NASA.
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October 24, 2000
Planet lovers campaign to save Pluto Express
July 28, 2000
Pluto may be stripped of planetary status
January 20, 1999
The Planetary Society
NASA Jet Propulsion Laboratory
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