The people in charge of NASA’s human spaceflight program have it tough—tougher in many respects than their predecessors did in the 1960s, when the goal was just to land astronauts on the moon. Not only is today’s destination, Mars, hundreds of times farther away, the path ahead—and even the rationale for going—are far less clear. A briefing chart currently popular with NASA managers, meant to illustrate the “Journey to Mars,” looks more like a Gordian knot than a roadmap.
Seven years ago, President Barack Obama canceled his predecessor’s return-to-the-moon program, which was widely deemed unaffordable, in favor of a “flexible path” to space exploration. NASA would stockpile technologies that could be applied to several future missions, without committing to any one. Only a near-term moon landing was taken off the table: “We’ve been there before,” said Obama.
But the flexible path ran into criticism of its own: too aimless, not bold enough. So NASA picked a specific, affordable goal for the next decade: send a robotic spacecraft to capture a small asteroid and return it to the vicinity of Earth and the moon, where astronauts could study it up close and collect samples for further investigation on the ground.
This two-part Asteroid Redirect Mission (ARM) is still, officially, NASA’s next planned venture beyond Earth orbit. A robot spacecraft will launch in 2020 toward a nearby asteroid, where it will remain for months, studying the object and testing methods for slightly altering its course (insurance against future asteroid collisions with Earth). Instead of bringing back the whole asteroid, the robot spacecraft will grab a multi-ton boulder from its surface and return that to the Earth-moon neighborhood, where astronauts will meet up with it in 2025.
Much of the hardware needed for this mission is now in design or production. Work on the crew’s Orion spacecraft and the Space Launch System (SLS) rocket will continue this year and next, with a first (uncrewed) flight scheduled for 2018, followed by the first launch of Orion with astronauts onboard in 2023. Meanwhile, NASA’s Goddard Spaceflight Center in Maryland is working on the capture mechanism and robotic tools for grabbing and securing the boulder.
The asteroid mission has never been especially popular; it stirs little passion in Congress or in the asteroid research community, which generally prefers cheaper, all-robot options. If the project were canceled tomorrow, most of its technology could be redirected to some other mission. The Orion and SLS can be used for any voyage beyond Earth orbit. NASA hopes to procure a common spacecraft “bus” for the robotic mission that could also be used for servicing satellites in Earth orbit. And last April, NASA’s advisory council recommended using advanced solar electric propulsion—probably the most significant technology expected to come out of the asteroid project—for another purpose. “Instead of relocating a boulder from an asteroid,” the council wrote, “we suggest that a more important and exciting first use of this new SEP stage would be a round-trip mission to Mars, flying it to Mars orbit and then back to the Earth-Moon system and into a distant retrograde lunar orbit.”
Lately, NASA spaceflight managers have talked less about the asteroid mission as an end in itself, and more about a general strategy for using the Earth-moon neighborhood as a “proving ground” (a NASA buzzword as popular these days as #TheRealMartians) to gain experience for Mars. By the mid-2020s, astronauts will have the means to travel beyond Earth orbit for the first time in half a century. NASA sees a range of possibilities for what might be accomplished on these “shakedown” flights, from tele-operating robots on the moon (even landing astronauts there, briefly!) to—oh, right—meeting up with a space boulder. Outside NASA, the moon seems more popular than Mars these days. In a year when Europe expects to make its first landing on the Martian surface, European Space Agency Director Jan Woerner has been pushing his idea of a lunar “village” as the next big multinational project after the current International Space Station.
Even if it holds to the current schedule, the astronauts-to-an-asteroid mission won’t happen until 2025, after Obama’s successor leaves office. So don’t be surprised if November’s presidential election hits the reset button again on NASA’s long-term plans. Nor should we expect another “Kennedy moment” in which the space agency gets a bold new assignment and the money to pull it off. For the next year or so, NASA will be plotting its own course, while keeping its options open. The flexible path seems more flexible than ever.