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By MARCIA DUNN, writer for aerospace
CAPE CANAVERAL, Fla. (AP) – A pair of tiny experimental satellites tracing NASA's InSight satellite to Mars is facing its biggest test so far.
Their mission: to spread immediate information, good or bad, on InSight diving in the Martian atmosphere on Monday.
Named WALL-E and EVE after the main characters of the 2008 animated film, the twin CubeSats will pass a few thousand kilometers from Mars when the LG will attempt his touchdown.
If these pipsqueaks manage to relay the InSight radio signals to the ground controllers to about 160 million kilometers, we will know in a few minutes if the spacecraft has landed safely.
A glance at the fantastic companions of InSight:
Hitchchiders
From the size of a briefcase, WALL-E and EVE have mounted the same rocket that launched InSight to Mars in May. CubeSats still share rockets; they are too small and inexpensive to guarantee their own launch. The Mars Cube One project, or MarCO, built and managed by NASA's Jet Propulsion Laboratory, cost $ 18.5 million.
FLIGHT TRAINING
NASA kept the CubeSats about 10,000 kilometers from InSight on the 300-mile journey to Mars to prevent collisions or close calls. Mini-satellites were as far apart from each other for the same reason. The room for maneuver in this "very loose training", as described by Chief Engineer Andy Klesh, has varied over the course of the mission and is shrinking as the spacecraft approaches Mars.
BETTER BEHAVIOR
For the record, EVE performed better than WALL-E during the 6 ½ month trip to Mars. Each CubeSat uses the same type of cold gas propulsion used in fire extinguishers to spray foam. In the movie, WALL-E uses a fire extinguisher to propel itself into space. In fact, WALL-E loses fuel almost since take-off. The flight controllers have solved the problem. Meanwhile, "EVE seems to follow his name and has been flying very well throughout the mission," Klesh said.
DRY RUN
In June, WALL-E and EVE performed a series of radio relay tests using signals from a large satellite dish located near Palo Alto, California. Klesh said it gave engineers confidence in the CubeSats' ability to do the same with InSight signals on the day of landing. Last month, the pair returned photos of Mars to 13 million kilometers. Mars was just a clarification, but the team said CubeSat was a first.
ALL OUIE
It takes eight minutes and seven seconds for a radio signal to pass from Mars to Earth, in a sense. It should take less than a minute to get an InSight message, if the mini-satellites cooperate. This means that NASA could know the fate of InSight almost in real time. If WALL-E and EVE are the moms, the confirmation will come directly from the LG or, a few hours later, from the space probe circling Mars.
GOAL FUTURE
As NASA explores new worlds, it would be useful to have outposts for retransmitting downhill and landing updates. Spacecraft already in orbit around Mars serve this purpose every time NASA sends a lander. But where there are no satellites – think of asteroids or dwarf planets on the periphery of our solar system – CubeSats could intervene, with little overhead and low cost.
BEYOND MARCH
Whether or not they provide information about InSight, WALL-E and EVE will fly over Mars and stay in an elliptical orbit around the sun. Engineers expect that they will continue to work a few weeks after March, depending on how long the fuel is stored and electronics.
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The Associated Press Science & Science Department is supported by the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.
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