Space flight instruments headed to Mars, Saturn to detect rock, soil composition

Thanasis Economou

Thanasis Economou’s to-do list extends hundreds of millions of miles into space.

Economou, a Senior Scientist in the Enrico Fermi Institute, is involved in the operation of two scientific instruments en route to Saturn and the comet Wild-2, three instruments that will be launched to Mars later this year and next year, and another instrument now under development that would detect water in the planetary bodies and may be headed for the moon to search for meteorites from Earth.

One of the instruments that Economou is operating is the University’s dust detector, which was aboard NASA’s Stardust space probe. The detector is coming off a successful Nov. 4, 2002, test during its encounter with asteroid Annefrank.

NASA is scheduled to launch in May the first of two Mars rovers carrying Chicago-invented chemical sensors. Another will follow in June. The APXS instruments are similar to one that Economou provided for the rover that explored the Mars Pathfinder landing site in 1996.

“One of the issues that came up on Pathfinder was that the rocks we analyzed were partially covered by soil and dust. You don’t know exactly what you are measuring, the soil or the rock,” Economou said.

This time the rover will measure the composition of the rocks, then scratch the dust and soil away with a special tool and measure the rocks again. “This way we will see the difference between the first analysis and the subsequent analysis,” he said.

Addressing NASA’s future in light of the crash of Space Shuttle Columbia, Economou said, “The Columbia tragedy is very unfortunate, and I am sure it will have a big impact on the entire NASA program. It will affect mostly the manned part of NASA’s program, and I hope it will not indirectly affect negatively the rest of the space program,” he added. “Definitely, it will not change the schedule for the next two launches to Mars.”

Economou also will participate in the European Space Agency’s Mars Express mission, which will be launched in June. Mars Express, an orbiter, includes the British-led Beagle 2 lander, which will carry a chemical analysis instrument.

Economou became a consultant to Beagle 2 after NASA withdrew from the Japanese MUSES-C mission to an asteroid. Economou had provided a miniature version of the APXS, called the Alpha X-ray Spectrometer, for the mission’s nanorover.

“I ended up with a flight instrument that I developed for that mission, which was very suitable for Beagle 2, so I offered this instrument to the British,” he said. The British decided to develop their own instrument, but they invited Economou to serve as an adviser to their X-ray Spectrometer science team.

During the Stardust flyby of asteroid Annefrank, Chicago’s Dust Flux Monitor was turned on and tested for nearly 28 minutes. The instrument had been turned off since May 2000, when it had been previously tested. “We were anxious to see if it would perform as expected, and it did perform as expected,” Economou said.

The instrument will measure the dust density around Wild-2 when Stardust flies within 93 miles of the comet in 2004. “The project used this opportunity for a dry run before the real run on the comet,” Economou said. “The more you practice, the better things will go when it counts.”

A similar instrument, the Cassini space probe’s High Rate Detector, will collect data on dust particles as the spacecraft crosses Saturn’s famous rings. The Chicago instruments for Stardust and Cassini were designed, developed and built by the principal investigator Anthony Tuzzolino, Senior Scientist in the Enrico Fermi Institute, and the late John Simpson, the Arthur Holly Compton Distinguished Service Professor Emeritus in Physics and the College.

Cassini is scheduled to enter Saturn’s orbit in July 2004.

“We’re hoping to see lots of activity during the Saturn orbit insertion and ring crossings,” Economou said.

Looking even farther into the future, Economou is developing an improved version of his APXS that also would detect water on any planetary body with a $200,000 NASA grant. Finding life in other planets is one of the most important goals in NASA’s space exploration, said Economou, and water is essential for life to exist.

“It’s far from the flight instrument, but the feasibility has been demonstrated,” he said. “One other idea is to go back to the moon and look for Earth meteorites.”

Finding Earth meteorites on the moon would be scientifically significant because some of them could be older than the oldest terrestrial rocks, which geologic processes systematically alter or destroy. The geologically inactive moon might have preserved relics from Earth’s early history, Economou said.