Maryland-made space probe to Mercury is set for launch

August 01, 2004|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

Preparations were on schedule in Cape Canaveral, Fla., for tomorrow's planned launch of the Maryland-built Messenger spacecraft on a 6 1/2 -year voyage to the planet Mercury.

Everything seemed ready, too, at the mission operations center at the Johns Hopkins University's Applied Physics Laboratory, near Laurel, where Messenger was designed and built.

"We've been practicing the launch-day procedures. ... We've done that a number of times already," said Andrew Santo, APL's deputy project manager for Messenger. "I think we're just ready to see it happen."

The only clouds on the mission's horizon were rain storms off the Florida coast.

"We don't think it's going to be a factor, but we're watching to see if it develops circulation or intensifies or moves in a direction not favorable to us," said George Diller, a spokesman at NASA's Kennedy Space Center.

Liftoff for the $426 million mission was set for 2:16 a.m. tomorrow, with a launch window just 12 seconds long. If bad weather or some other problem arises, the launch could be delayed each night through Aug. 14.

Final preparations over the weekend included fueling and the removal of protective covers on some of Messenger's instruments and thruster engine.

At the APL, everyone seemed ready. "There's not a lot of rushing around ... no last-minute heroics," Santo said.

Fingers may be crossed tomorrow anyway. The lab's $159 million Contour spacecraft, built for NASA, was lost in August 2002, six weeks after its launch, when a solid-fuel rocket motor blew apart at the end of a critical firing. Messenger officials said their craft has a liquid-fuel thruster and no systems in common with Contour.

In December 1998, a liquid-fuel thruster misfired on the APL's NEAR spacecraft en route to the asteroid Eros. Flight controllers at APL recovered quickly, however. They got their craft to Eros a year later despite a major fuel loss. It orbited for a year, sending back a wealth of data. Controllers even dropped NEAR onto the asteroid's surface at the mission's end.

If all goes well tomorrow, Messenger will rise into the night sky over Pad 17-B at the Cape Canaveral Air Force Station atop its Delta II rocket. The rocket's third stage will hurl the spacecraft out of Earth orbit, on a circuitous, 4.9 billion-mile journey to Mercury.

About 20 controllers will man the APL operations center 24 hours a day for the first week after launch, Santo said. They'll monitor the first data from the spacecraft, expected about an hour after launch, to assure that Messenger's solar panels have opened and all its systems are working.

Tracking data will also be assessed to plan any course corrections that may be needed in the first weeks of the flight.

After about a month, Messenger will slip into "hibernation," waking for just eight hours every three days to report its status to APL controllers and to receive any new commands.

After a series of five rocket firings and swings past Earth, Venus (twice) and Mercury (three times), Messenger will slip into orbit around the sun's nearest neighbor in March 2011.

The only other spacecraft ever to visit Mercury was NASA's Mariner 10 mission. Mariner buzzed the planet three times in 1973 and 1974.

For an updated article on the Messenger launch, go to baltimoresun.com/messenger.

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