NASA: Volcano on Io producing lava flows, tubes

A high-resolution image of part of Prometheus, an active volcano on Jupiter's volcanic moon Io

November 5, 1999
Web posted at: 12:08 p.m. EST (1708 GMT)

(CNN) -- New high-resolution images of a volcanic crater on Jupiter's moon Io suggest it's remarkably similar to craters of the Kilauea volcano in Hawaii, only several times larger, NASA said Thursday.

Both Io's Prometheus volcano and Hawaii's Kilauea have long-lived eruptions, with flows that apparently travel through lava tubes and produce plumes when they interact with cooler materials, said Dr. Laszlo Keszthelyi, a Galileo spacecraft research associate at the University of Arizona, Tuscon.

The sharp images of Prometheus released this week were taken during the close fly-by of Io by Galileo on October 10, 1999, and are part of a large batch of data currently being transmitted to Earth.

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"We've been having a feast looking at the material from Io," said Dr. Rosaly Lopes-Gautier NASA's Jet Propulsion Laboratory, Pasadena, California. "We have been waiting for such high-resolution images of Io for more than 10 years.

Scientists will present an assortment of new images and describe their latest discoveries at a news briefing scheduled for November 19 at NASA Headquarters in Washington, D.C.

Prometheus, the "Old Faithful" of Io's many volcanoes, has been active during every observation over the past 20 years by NASA's Voyager and Galileo spacecraft and the Hubble Space Telescope.

New spectrometer images show two distinct hot spots at Prometheus -- a large one to the west and a fainter, cooler one to the east. The images reveal numerous lava flows near the western hot spot and enable scientists to identify a crater, or caldera, 28 kilometers (17 miles) long and 14 kilometers (9 miles) wide near the hot spot to the east.

Another Io fly-by, this time at an altitude of 300 kilometers (186 miles), is planned for November 25. The Io fly-bys are challenging and risky, because Io lies in an area of intense radiation from Jupiter's radiation belts, and that radiation can harm spacecraft components.

The main mission for Galileo ended two years ago. Since then the orbiter has been conducting a two-year extended study of Jupiter's largest moons -- Ganymede, Callisto, Europa and Io.

That funding, about $30 million, will run out at the end of the year, but NASA managers are working on another possible extension, Johnson said.

With more funding, Galileo could return observations of Jupiter simultaneously with NASA's Saturn-bound Cassini spacecraft during its jovian fly-by in December 2000.