Earth_Magazine_October_2017

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for reuse, and during those landing tests, it had also

reportedly conducted retropropulsion experiments

at high altitude, where Earth’s atmosphere is similar

in density to Mars’. A successful trial of supersonic

retropropulsion on Mars would be “a huge step,”

proving we can deliver the heavy equipment needed

for settlements to the surface, Hecht says. And before

that, the technology could be used to help carry “a

small load of bricks off the surface and bring it home

so we can study Mars in laboratories.”

However, unless SpaceX reinstates the thrust-

er-equipped Red Dragon mission soon, it appears

that the trial will have to wait, and perhaps be led by

someone else. Supersonic retropropulsion has long

been a goal for NASA, and an information-sharing

agreement with SpaceX provided the agency with

valuable flight-test data in recent years. It remains

to be seen if NASA will accelerate its own pro-

gram to develop the technology, or if other options

are available.

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With missions taking years to plan and fac-

ing limited launch opportunities, frequent delays

and a historically high rate of failure, milestones

in Mars exploration are difficult to predict. The

failure of NASA’s Mars Climate Orbiter and Mars

Polar Lander upon arrival at the planet in 1999,

for example, was a major setback for the agency’s

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