Mars Express power glitch a minor annoyance, ESA says

Posted: July 8, 2003

Europe's Mars Express orbiter is now over one month into its marathon cruise to the Red Planet, and although the ground team has discovered a few of the probe's quirks in testing, project officials contend the spacecraft is performing well.

An artist's illustration of Mars Express. Credit: ESA
Launched aboard a Russian Soyuz rocket on June 2, the continent's first mission to Mars is less than one-fifth of the way through its long journey that will see it arrive in orbit around the planet around Christmas Day.

Once controllers established contact with Mars Express and affirmed its health status, they began checking out each of its systems and science instruments. In addition, tests of the Beagle 2 lander riding piggyback on Mars Express were to be carried out.

While testing one of the orbiter's instruments, the craft's solid state mass memory unit began sending error-filled messages for a short time before the problem suddenly disappeared. To allow time to understand the issue, officials rescheduled the checkout of Beagle 2's armada of experiments and systems until the first week of July.

That critical milestone came late last week, Mars Express project manager Rudi Schmidt said. The Beagle 2 checkout also marked the end of the initial commissioning phase of the mission -- meaning all systems had been switched on and evaluated.

Meanwhile, the attention of many in the project has been focused a few issues that arose as engineers methodically went through the innards of the probe one-by-one to make sure they were functioning as expected.

The momentary malfunction of the memory unit first appeared last month, but the flight support team soon found a solution. "The (memory unit) issue is largely understood and a software patch will cure it," Schmidt told Spaceflight Now.

Perhaps a more serious problem cropped up as controllers checked out the power production systems aboard Mars Express. The discovery of an interconnection anomaly between the electricity-producing solar arrays and the craft's power conditioning unit was well-publicized after a European Space Agency statement said the issue could cause operations to be reviewed for "certain short periods of the mission."

The consequence of the interconnection problem is believed to reduce the usable power from the solar panels to about 70 percent of the original plan. ESA says this has no impact on the spacecraft during the remaining six months of transit on the way to the Red Planet or during the make-or-break orbital injection maneuver to begin its mission.

Schmidt clarified the potential mission impact Monday in a response to written questions. "If we confirm the 70 percent number, there will hardly be any impact on the science mission due to higher margins and overdesign in the power system. Only during long eclipses (four periods of a few days during the mission) there could be a need to optimize the instrument operations."

It is too early to tell if the power production problem has a possibility of being resolved, Schmidt said. "We have no power problem until Christmas and therefore we take our time to understand the issue."

The most recent series of tests involved the British Beagle 2 lander that will deploy various scientific instruments once on the Martian surface to help look for past life there. All systems reportedly checked out perfectly, and scientists currently have no concerns with the small craft that will bounce to soft landing December 25.

With the initial phases of commissioning completed, the Mars Express team will continue preparations for arrival at the Red Planet over the coming months.

Star calibrations of some Mars Express instruments could come as early as mid-July, ESA said. Other tests will be performed as the probe nears Mars later this year.

"This checkout was a marvelous example of complete cooperation between ESA's Mars Express and the Beagle lander teams," Schmidt said. "Another major milestone has been achieved successfully. What a fantastic feeling!"

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