AT 50,000 kilometres per hour, even minuscule pieces of space junk can tear a
satellite to pieces. But simplified software should help satellites dodge this
orbital shrapnel.
Right now, only the International Space Station and the space shuttle make a
point of getting out of the way of junk, says Nick Johnson, an orbital debris
expert at NASA in Houston. They plan their collision-avoidance manoeuvres via a
detailed computer model鈥攂ut the calculations are complex and take hours to
run.
But by stripping down the detailed model to a simple equation, Russell Patera
of the Aerospace Corporation in Los Angeles says satellites can work out their
manoeuvres in a fraction of the time. 鈥淵ou forget about the Sun鈥檚 gravity, the
Moon鈥檚 gravity, the solar wind and so on,鈥� he says. 鈥淵ou just take the Earth鈥檚
gravitational field into account.鈥� Because this reduces the calculation time to
seconds, Patera says satellite operators could test a number of different moves
to work out the most efficient manoeuvre, saving them fuel.
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