NASA’s Asteroid Redirect Mission has always been a bit of an ugly duckling. It wasn’t out of love that the space agency came up with the plan to scoop a small boulder from the surface of an asteroid and return it to a location near the moon. Rather, after President Obama’s call for people to visit an asteroid in the mid-2020s, it was the only way NASA could afford to fulfill such a mandate.
Since the formulation of the mission, Congress has generally rejected sending astronauts to a small boulder formation around the moon as a stunt. Many planetary scientists, too, never really embraced the plan, unsure of its value when NASA was already flying a robotic sample return mission to an asteroid, OSIRIS-REx.
The aerospace community generally believes that the Trump administration will shelve the asteroid mission in the coming months. Further confirmation of this came in late November from House Science Committee chairman and Trump ally Lamar Smith (R-Tex.), who sent a letter to NASA Administrator Charles Bolden critical of the mission, claiming that it ” “forced on NASA” by the Obama administration and supported by “farcical studies.”
Even within NASA, support for the mission is mixed. During the years of the mission’s development, from 2012 to 2016, former astronaut John Grunsfeld led the space agency’s science missions directorate. While he was not overtly critical of the asteroid mission during his time at the space agency, since leaving NASA, the five-time astronaut has promoted a dramatic alternative that would align with the agency’s goal of eventually sending humans to Mars. The plan, which would likely use SpaceX’s Red Dragon spacecraft, would give NASA several new and powerful capabilities, including a map of all-water ice on Mars and a long-coveted return of Martian rocks to Earth.
Ratty Mars comm
Exploration of Mars depends on logistics, primarily overhead imaging capability and high-bandwidth communications. “This is exactly the problem our generals have in every theater they operate on Earth,” Grunsfeld explained in an interview with Ars. “If they go and plan an operation, they want to know what their resources are for communications and satellite reconnaissance.”
Right now, NASA relies on repurposing old science spacecraft, such as the Mars Reconnaissance Orbiter and Mars Odyssey, for communications, but the space agency can’t rely on these aging vehicles to survive into the early 2020s. Grunsfeld said the next step is for NASA to launch a communications spacecraft to Mars in 2022, the next available window after the launch of the Mars 2020 rover. “Right now, most of what happens on Mars stays on Mars because we don’t have the bandwidth to get the data back,” Grunsfeld said. Instead of megabits, scientists need gigabits to send back observations from rovers and orbiters.
In addition to communications, Grunsfeld believes the spacecraft launching in 2020 should include a high-resolution imaging sensor and ground-penetrating radar, which can map all accessible ice sources for science and for human exploration. The problem with such a mapping mission is that it would require large amounts of power for the radar and could therefore cost as much as $1 billion.
Power, you say?
While Congress hates the idea of sending a robotic spacecraft to retrieve a boulder from an asteroid, it supports some of the technology behind the mission, particularly solar-electric propulsion, which uses a solar-powered energy-powered ion propulsion used to propel a spacecraft. This propellant, while slower than a conventional rocket, is seen as a useful means of moving payloads around the solar system because it uses significantly less fuel. There is widespread support for a “demonstration” mission of solar electric propulsion (SEP), just not one to an asteroid, which appears to be a distraction from NASA’s plans to explore cislunar space and then Mars with humans.
NASA
Grunsfeld’s idea goes like this: Instead of sending the powerful SEP spacecraft to an asteroid, reconfigure it by adding a communications satellite, imager, and ground-penetrating radar. The SEP spacecraft could then go to Mars and provide all the power the radar needs to map the entire planet’s water resources over the course of a Martian year. Once the radar’s work was done, the SEP spacecraft could be detached, leaving NASA with an entirely new communications and imaging satellite.
Meanwhile, another spacecraft could launch to Mars in 2024 — perhaps one of SpaceX’s Red Dragons, Grunsfeld said — using a small rover and a Mars liftoff vehicle. This rover would have the primary purpose of collecting Martian rock samples cached on the Mars 2020 rover and then returning it to the ascent vehicle. After launching into Mars orbit, the liftoff vehicle would dock with the SEP spacecraft and return to Earth.
Consider the possible outcomes of this two-mission strategy. By 2025, NASA would have a new high-bandwidth communications and imaging satellite in orbit around Mars; find there all the water people need; demonstrate solar electric propulsion; prove it is possible to conduct a return flight to Mars before humans are sent and; finally, conduct a Mars monster return mission, the top priority of the planetary science community.
“A lot of people like this idea,” Grunsfeld said. But, he added with a shrug, “It’s not the current baseline.” That’s code for NASA being an agency of the White House. The president has designated NASA to visit an asteroid, and so the agency will continue to plan for it. For now. The mandate to visit an asteroid will evaporate in January.
SpaceX
When the Trump transition team and congressional aides review the asteroid mission, they will likely sink it. However, given the widespread interest in developing SEP technology, some kind of demonstration mission, a new baseline, will be needed.
The estimated cost of the asteroid retrieval mission, just the spacecraft and the boulder-grabbing mechanism, has already risen to $1.4 billion. With launch costs, this could add up to about $2 billion before it takes flight in early 2020. This estimated cost is not much less than it would cost to implement Grunsfeld’s two-mission Mars strategy and reap the significantly broader range of benefits.