NASA provides update on Asteroid Redirect Mission
NASA provided an update on their Asteroid Redirect Mission (ARM) during a series of internet-streamed events on Sept. 14, 2016, from the agency’s Goddard Space Flight Center. Long a mission with lukewarm support in many sectors, NASA provided subject matter experts, as well as agency leaders and governmental advisors, giving them the chance to feature some mission hardware and outline the key benefits to be gained from ARM.
The early panel discussion featured Dr. John P. Holdren (Assistant to the President for Science and Technology), NASA Administrator Charles Bolden, and Dr. Michelle Gates (NASA’s ARM Program Director). Dr. Holdren was quick to assure the current administration’s support of the program.
“I wanted to put the ARM mission in context of the President’s and NASA’s vision for expanding the human exploration of space,” Holdren said. “That vision is ambitious, it’s coherent, it’s systematic, it has four major pieces.”
First among those pieces that Holdren outlined is the intent to work with private industry in order to develop the most cost-effective mission design and hardware possible. He also noted that developing new technologies in support of a crewed mission to Mars – such as in-space refueling, crew habitation modules, life support, planetary protection, and advanced propulsion – is a cornerstone of ARM.
Dr. Holdren noted that the International Space Station (ISS) can be a vital player in ARM, and extending its life into the mid-2020s will allow it to be used as a technology testbed, as well as providing an important science and diplomatic platform as the agency works to support increasingly ambitious missions.
The mission itself has a projected launch date of December 2021 for the robotic component and some time in the mid-2020s for the crewed mission. NASA has given the program the go-ahead to proceed to Phase B, culminating in a preliminary design review and baseline of the robotic spacecraft in late 2017. The crewed mission is still in the very early discussion phase.
Administrator Bolden expanded on some of Dr. Holdren’s points, noting that it is NASA’s intent to develop technology and techniques that can later be used by private industry.
All three panelists were advocates of ARM being a necessary component of the agency’s Journey to Mars. Fitting into the “proving ground” area between low-Earth orbit (LEO) and Earth-independent deep space missions, ARM provides the opportunity for NASA to test key hardware, such as advanced solar electric propulsion, in a region only days away from Earth rather than months as would be the case for a Mars mission.
Indeed, advanced solar electric propulsion (SEP) has been touted as a critical need for travel to the Red Planet in order to minimize vehicle mass while keeping mission duration within reasonable limits. SEP is not a new technology and has been a core propulsion component of many Earth-centric satellites, as well as notable deep space robotic explorers like NASA’s Dawn spacecraft.
However, SEP will need to be a couple orders of magnitude more powerful than the 2 kilowatt unit on Dawn if it is to be used for a crewed mission. Working toward the goal of a human-rated 200–500 kilowatt SEP unit for a Mars transit, ARM mission designs call for a 50 kilowatt SEP engine for the spacecraft.
Rather than using traditional chemical propellant, which can be heavy and, in some cases, difficult to store for the long periods of time necessary on extended missions, SEP works by accelerating charged particles of a gas – such as xenon or argon – through an electrically-charged grid, producing a small amount of thrust. ARM will be used to demonstrate the feasibility of using SEP to maneuver large masses in space, a critical need for sending cargo to Mars.
Scientific study is another pillar of the mission. Though the agency recently launched the OSIRIS-REx mission to the asteroid Bennu, with the hopes of recovering up to 4.4 pounds (2 kilograms) of material from the planetoid, it has an entirely different set of science objectives than does ARM. A goal of the crewed component of ARM is to retrieve up to 220 pounds (100 kilograms) of pristine material and return it to Earth, with the goal of determining the asteroid’s makeup and suitability for resource exploitation.
Though mission designers have yet to formally select a target, asteroid 2008 EV5 is being used as a reference body in simulations. Scientists estimate that water – highly sought for both life support needs and for conversion into propellant – may comprise up to 20 percent of the asteroid’s mass.
Dr. Gates echoed her panelists’ affirmation of the mission’s ultimate goal, stating: “The Asteroid Redirect Mission really is a vital step in our Journey to Mars.” Noting that the crewed component of the mission will launch in ten years, many of the skills necessary for ARM will also be needed on a future trip to the Martian system.
While hardware advancement, science, and exploration are all worthy goals, they may not necessarily resonate with the public. However, having the ability to protect Earth from a possible catastrophic asteroid strike is a tangible project, easily understandable to many as being a necessary skill for humanity to possess.
Planetary protection supporters have touted the ability of ARM to demonstrate a method of altering an incoming planetoid’s path by means of a “gravity tractor” technique – using the mass of the spacecraft and a sizable boulder collected from the asteroid to create a gravitational field sufficient to ‘tug’ the asteroid. Simulations suggest that it is possible to deflect an incoming body without the need to use a more direct, and potentially less effective, means of diversion – such as a nuclear detonation or an impactor.
Given enough time in close proximity with the asteroid, the “gravity tractor” will slowly nudge the body away, potentially averting a planetary disaster.
“This is a hazard that, 65 million years ago, the dinosaurs succumbed to,” noted Dr. Holdren. “We have to be smarter than the dinosaurs.”
Video courtesy of NASA
Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.