CAPE CANAVERAL, Fla. -- Europe's first science probe to the Moon successfully test fired its ion thruster this week and all other systems are checking out fine, program officials reported Wednesday.
The Small Missions for Advanced Research and Technology (SMART-1) lunar probe was lofted into Earth orbit on Sept. 27 by an Ariane 5 rocket launched from the Guiana Space Center in South America.
Along with two communications satellites, SMART-1 was sent into a very high parking orbit over Earth. From there it will use its ion engine to adjust the shape and raise the altitude of its orbit until it reaches the Moon.
Not as powerful as the ion drives of science fiction, this ion thruster uses electricity from solar arrays to charge a stream of xenon gas. The resulting flow of ions from a nozzle gives the spacecraft a very gentle push through space. The benefit of the ion thruster over conventional chemical rocket engines is that an ion engine can be left on for days and weeks at a time, providing a constant acceleration to the spacecraft with much less energy.
With chemical rocket engines you get one big burst of thrust that lasts only a few minutes, sending the spacecraft coasting to its destination.
For SMART-1 the slow process of raising its orbit with its ion thruster will continue for some 18 months until it reaches a point in space where the Moon's gravity will capture the probe and slingshot it into a lunar orbit.
To prepare the Swedish-built spacecraft for that journey, SMART-1's ion thruster was test fired for one hour at 8:25 a.m. EDT (1225 GMT) on Tuesday. European Space Agency (ESA) officials say all went well.
"The data will now be analysed to see how much acceleration was achieved and how smoothly the spacecraft travelled. If the ion engine is performing to expectations, ESA engineers will regularly power up the (engine) to send SMART-1 on its way," program officials said in a statement today.
Shortly after arriving in lunar orbit in March 2005, SMART-1 will begin a six-month science mission.
Instruments aboard the spacecraft are to map the lunar surface in fine detail and work to find new evidence that will solve the mystery of how the Moon was formed more than four billion years ago.
The leading theory holds that a Mars-sized object once slammed into Earth and the resulting debris then combined in orbit to form the Moon. But more observations still are needed to prove the idea.
Other devices on the spacecraft might help confirm if there is water ice hiding in shadows within craters near the lunar poles, as some previous observations have hinted.
Finding water ice on the Moon would be a big deal because the hydrogen and oxygen atoms that make up molecules of water could provide a source of fuel and air for future explorers or colonists.
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