How NASA Plans to Capture Life From an Asteroid
The most exciting space sample retrieval mission since the Apollo program.
NASA’s OSIRIS-REx mission may have a strange name, but it certainly hasn’t received as much public attention as a SpaceX launch does every month. That’s a shame, because the mission will attempt to retrieve organic material from an asteroid and bring it back to Earth.
If all goes well, astrophysicists and astrobiologists could use the sample to uncover insights about the origins of the solar system and life in the universe.
All NASA has to do is launch the robotic OSIRIS-REx spacecraft on September 8, send it to a near-Earth asteroid called Bennu, land it on the surface of the hurtling hunk of space rock, collect a sample, and come back to Earth in one piece.
“Make no mistake: This is not an easy mission,” said Jim Green, director of the Planetary Science Division at NASA, at a press conference on Wednesday.
The mission has many other implications in the realms of robotics, commercial asteroid mining, and asteroid impact avoidance. But by and large, the single most audacious part about this mission is the potential to learn whether the precursor compounds necessary for life to evolve and grow do indeed exist on rocks that are over four billion years old — essentially witnesses to the “dawn of the solar system,” said OSIRIS-REx principal investigator Dante Lauretta from the University of Arizona.
Lauretta explained that when a star system is in its infancy, asteroids in the vicinity begin to come together to form bigger bodies like planets and moons. These bigger rocks themselves are pummeled with other asteroids, which can do two major things: Seed those planets with precursor organic compounds that could one day lead to the evolution of primitive life, or hit the planet so hard so as to sterilize it and leave in inhabitable.
Bringing back an asteroid sample for analysis here on Earth means the ability to identify those organic molecules that haven’t been burned up or degraded when they’re hitching rides on meteorites that end up crashing into the surface of the earth. “With OSIRIS-REx,” said Lauretta, “we will have control of the evidence from the time it’s collected on the asteroid to the time it’s in our laboratories.”
The asteroid OSIRIS-REx will rendezvous with is called 101955 Bennu. Says to Christina Richey, OSIRIS-REx program scientist, Bennu was chosen based on three major criteria. In the first case, the asteroid orbits the sun at about 0.8 to 1.3 astronomical units (1 AU = the distance of the sun to the Earth), and passes by our planet every six years, so it’s pretty easily accessible. It’s about 1,614 feet in diameter — not too small such that the spacecraft will have to match an extremely high rotational speed, and not too big that it would be an unwieldy rock to map and study. Lastly, preliminary studies of Bennu over the last decade indicate “there’s a potential for organic molecules to be there,” said Richey.
The task at hand for the $800 million dollar mission is to launch OSIRIS-REx to launch next month, fly around Earth next year and use the planet’s gravity to slingshot it at a higher velocity toward Bennu, approach and insert itself into the asteroid’s orbit by late 2018, map and study the rock from a distance, and take a nominal sample by around July 2020.
OSIRIS-REx won’t technically land on Bennu, but will basically make contact with its surface for about five seconds, when the spacecraft will release a compressed gas to agitate enough material and collect it into the sample retrieval capsule. The goal is to acquire about 60 grams of rock, but it could be as much as several hundred grams.
After that, the idea is to have the spacecraft make its way back home to Earth by September 2023. OSIRIS-REx will jettison the sample capsule into the Earth’s atmosphere for landing in the New Mexico desert, while the spacecraft goes into a parking orbit around the sun.
NASA anticipates that Bennu’s material will be studied for several generations afterward, just as the lunar samples brought back from Apollo were and still are researched. “Sample return is the gift that keeps on giving,” said Lauretta.
What those scientists find could transform what we know about the birth of the solar system and Earth, and how habitable planets form. “We’re going to a new world with Bennu,” said Lauretta. “We really are going out into the unknown.”