The flight team for NASA’s Jupiter-orbiting Galileo spacecraft will cease operations on Friday, Feb. 28 after a final playback of scientific data from the robotic explorer’s tape recorder. On Nov. 5, 2002, the orbiter passed closer to Jupiter than it had ever ventured before, flying near an inner moon named Amalthea and through part of Jupiter’s gossamer ring to begin its 35th and last orbit around the giant planet. Galileo will coast for the next seven months before transmitting a few hours of science measurements in real time, leading up to a Sept. 21 plunge into Jupiter’s atmosphere just like the science probe the Galileo orbiter released years ago. “After this month, we have no further activities planned until the day of impact,” Theilig said.

Galileo’s onboard supply of propellant is nearly depleted. Without propellant, the spacecraft would not be able to point its antenna toward Earth nor adjust its trajectory, so controlling the spacecraft would no longer be possible. Before that could happen, the flight team last year put Galileo on course for disposal by a dive into the crushing pressure of Jupiter’s atmosphere. This strategy eliminates any possibility of an unwanted impact between the spacecraft and the moon Europa. Galileo’s own discovery of a likely subsurface ocean on Europa has raised interest in the possibility of life there and concern about protecting it. Future NASA exploration of Jupiter hinged on the Europa Orbiter which was cancelled from the NASA 2003 budget and replaced by the nuclear-powered Jupiter Icy Moons Orbiter which will only become a reality if the new Project Prometheus does.