As Ars Technica noted, the FY 2017 NASA budget proposal from the White House contains funding for the asteroid redirect mission (ARM) but delays the start of it from 2019 to 2023. ARM is a very strange proposed mission that has evolved over time and for which no one can find a sound purpose, even in the asteroid science community.
The asteroid mission started in April 2010 when, during his now infamous speech at the Kennedy #Space Center, President Barack Obama proposed that astronauts visit an Earth-approaching asteroid before the ultimate mission to Mars. The asteroid mission would have taken astronauts on a voyage of some weeks through millions of miles of deep space, a feat that would have tested a number of technologies that would then be used for the Journey to Mars.
By 2012, thanks to a study by the Keck Institute for Space Studies, the mission to an asteroid became the asteroid redirect mission. Instead of sending astronauts to an asteroid, NASA would send a robot probe to a small asteroid and would divert it into lunar orbit. Then astronauts, riding an Orion spacecraft launched by a heavy-lift Space Launch System rocket, would visit the diverted asteroid. Later, the mission morphed again into snatching a small boulder from an asteroid and moving it into lunar orbit.
Richard Binzel, an MIT scientist and one of the world’s leading experts on asteroids and other small celestial bodies, denounced the ARM as a “multimillion dollar stunt.” Dr. Binzel suggested that NASA return to the idea of visiting an asteroid in its “native orbit” as a proper stepping stone to Mars. Binzel also urges NASA to step up the hunt for Earth-approaching asteroids, some of which may threaten the Earth.
Other scientists suggest abandoning the ARM altogether and sending the robot that would have snagged the boulder to and from a moon of Mars, perhaps as a sample return mission.
How long ARM will survive is open to question. Despite its lack of support, Congress has been reluctant to cancel it altogether. On the other hand, the next president is likely to revisit the mission and much else NASA is undertaking upon assuming office.