Earth_Magazine_October_2017

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A Diverse Group of Missions Takes Aim at the Red Planet

Timothy Oleson

A

bout every 26 months, the positions

of Earth and Mars in their respective

orbits align for a few weeks such that

spacecraft can take the shortest possible

route to the Red Planet. A shorter trip means less

fuel — and consequently less mass — to carry, as well

as less time for mishaps to occur in transit. These are

compelling factors for cost- and weight-conscious

mission planners, so it’s during these brief, roughly

biennial launch windows that space agencies have

typically sent spacecraft to Mars.

Recent launch windows have seen, on average, just

one to two missions depart for Mars (see table, page

28 ). This coming spring, NASA will send another

two, both aboard the same rocket: the Mars interi-

or-scanning InSight lander, as well as Mars Cube One,

which consists of a pair of briefcase-sized cubesats

designed to relay data about InSight’s landing as they

fly by Mars.

In contrast to the modest pace of late, as many

as five or six Mars missions might launch in late

July or early August 2020. These missions include

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