Europe Observes Deep Impact in Preparation for Rosetta

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European scientists trained three orbiting satellites and one ground telescope on the Tempel 1 comet to catch the live action as NASA’s Deep Impact slammed into its target July 4.

The European Space Agency (ESA) oriented its XMM-Newton X-ray satellite and the narrow-angle camera aboard Europe’s own comet-chaser satellite, Rosetta, on Temple 1 to record before-and-after impact data.

In addition, the agency’s Optical Ground Telescope on Spain’s Canary Islands was used to measure the brightness of the dust being thrown off Tempel 1 before impact, and then again 15 hours after Deep Impact had hit home.

Sweden’s Odin satellite, launched in 2001 on a dual astronomy and atmospheric-research mission, measured water-vapor levels on and around Tempel-1 before and after impact, and will continue taking measurements every three days until mid-August, according to the Swedish Space Corp. of Solna, Sweden, which operates Odin.

ESA Science Director David Southwood said in a July 4 statement that the NASA mission “brought the world together in an excellent opportunity to make a new step into the advancement of cometary science.”

The coordinated activity and post-mission praise suggest scientists around the world working as a single, borderless team. But some European officials struck a much different tone in 2003 and 2004, before and just after the March 2004 launch of the billion-dollar Rosetta satellite.

In remarks that perhaps reflected the trans-Atlantic tensions resulting from the U.S.-led invasion of Iraq, several European scientists dismissed Deep Impact as an example of the brute-force mentality sometimes associated with the United States.

Marcello Coradini, ESA solar systems mission coordinator, in an address at the French space agency, CNES, invited his audience to contrast Deep Impact with Europe’s Philae lander on board Rosetta.

“Deep Impact is just going to smash into its target,” Coradini said. “This is the American approach. Philae is going to gently land on Churyumov-Gerasimenko [its target comet]. It’s obviously a very different approach that we are taking in Europe, a less violent one.”

One of Philae’s French mission designers, speaking informally at Europe’s Guiana Space Center spaceport while waiting for the Rosetta launch, dismissed Deep Impact as little more than a Hollywood-style spectacle with little scientific promise. It might be useful for the Pentagon, this official said.

Among the many differences between Rosetta/Philae and Deep Impact is the time delay between launch and scientific results. Deep Impact was launched in January and reached its destination six months later.

Rosetta and its attached Philae lander were launched in March 2004 and are scheduled to arrive at their selected comet sometime in 2014. After six months of reconnaissance around the 4-kilometer-diameter Churyumov-Gerasimenko to select a landing spot, Rosetta will eject the 100-kilogram Philae.

The lander is designed to perform a risky penetration maneuver to attach itself to the comet. Once attached, Philae will ride the comet as it heads to the center of the solar system, with Rosetta following.

Southwood said of Deep Impact: “The results are going to be a terrific help in planning Rosetta’s comet landing a decade from now.”

Don Yeomans, a Deep Impact mission co-investigator for NASA’s Jet Propulsion Laboratory in Pasadena, Calif., said July 4 that he hoped the success of Deep Impact would lead to more ambitious missions.

Rosetta is the next step, he said, “to actually rendezvous with a comet, orbit it, and then land and do surface analysis.”

Ultimately, Yeomans said, the most ambitious mission would be to land on a comet, take a sample and return it for study in Earth-based laboratories. “There have been proposals to do just that. Nothing funded,” he said. “But we’re thinking that way.”

Anthony Duignan-Cabrera contributed to this article from Pasadena, Calif.