Venus Express Data To Bring ‘Fresh European Perspective’

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  Space News Business

Venus Express Data To Bring ‘Fresh European Perspective’

By PETER B. de SELDING
Space News Staff Writer
posted: 17 April 2006
01:21 pm ET


The European Space Agency (ESA) plans to begin making observations with its Venus Express satellite almost immediately to take advantage of the probe’s current temporary position, ESA officials said.

The early viewing time will occur before the satellite reaches its final operating orbit and before a full checkout of its suite of observing instruments.

Launched in November, Venus Express arrived in its initial orbit around Venus April 11 following a 50-minute firing of its main engine that enabled the satellite to slow down and be captured by the planet’s gravitational force.

If the engine had not fired on schedule, or if its burn had stopped too far short of 50 minutes, “we basically would just fly past the planet,” said Don McCoy, Venus Express project manager at ESA.

The maneuver, which had been programmed into the satellite’s computers several days earlier, went without a hitch, according to ESA officials here at the agency’s Esoc mission control center.

The satellite currently orbits Venus every nine days at an altitude ranging from 350,000 kilometers to less than 400 kilometers. Further firings of the main engine and the satellite’s maneuvering thrusters in the coming weeks will result in a final 24-hour orbit of 66,000 kilometers by 250 kilometers, expected to be reached by May 7.

A fresh series of instrument tests over four weeks should result in the satellite beginning full scientific operations with its seven observing instruments in early June.

But Manfred Warhaut, Venus Express flight operations director, said scientists have asked that they make at least partial use of the satellite in its current position to profit from the more-distant vantage point.

“They can take advantage of the nine-day orbit to use the payload from large distances to make observations of Venus, which they would not be in a position to do later on,” Warhaut said here after the satellite’s successful orbital insertion.

Venus Express was built by EADS Astrium in an unusually short period of time for a science spacecraft — three years from contract to launch — because the company proposed the mission in a reversal of the normal roles played by industry and scientists.

The satellite’s skeletal structure and payload borrow heavily from work done on ESA’s EADS Astrium-built Mars Express spacecraft, which is currently in orbit around the red planet, and from the payload on board ESA’s Rosetta comet-chaser satellite.

Reusing elements of these spacecraft permitted Venus Express to be managed inside a total budget of 220 million euros ($266 million), including the satellite’s construction, launch and about 16 months of science operations.

“It cost us far less than it would have if we had built the mission from scratch — we saved on the order of 100 million euros just by building Venus Express in the slipstream of Mars Express, which was built in the slipstream of Rosetta,” ESA Science Director David Southwood said.

As he has done in past ESA missions, Southwood said that while U.S. and Russian satellites have visited Venus before — some 20 missions starting in the early 1960s — Venus Express brings a fresh European perspective.

“We Europeans look at things differently, we come from a different culture,” Southwood said. “It’s important for us to do our own planetary exploration.”

Hakan Svedhem, ESA’s Venus Express project scientist, said the satellite’s instruments will deliver more data on Venus than all previous missions combined, with the possible exception of the NASA Magellan satellite, whose radar instrument returned a wealth of data.

In the 12 years since Magellan ended its four-year mission, global warming and the greenhouse effect here on Earth have taken center stage among environmental concerns. ESA officials said Venus Express may find clues useful on Earth from a planet at which the greenhouse effect has gone to extremes.

Venus and Earth share similarities of size, mass and age. But for reasons not yet understood, Venus’ atmosphere built up huge amounts of carbon dioxide that have trapped the sun’s heat and driven surface temperatures to around 477 degrees Celsius.

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