NASA’s first spacecraft to travel to an asteroid will get a boost from Earth tomorrow, Sept. 22.
Earth’s gravity is going to slingshot OSIRIS-REx toward its target, an asteroid named Bennu.
Asteroids are relatively small, inactive, rocky bodies that orbit around the Sun. Scientists think asteroids like Bennu may have collided with Earth a long time ago, seeding our planet with the organic compounds that made life possible. That means that there’s a good chance Bennu contains answers to fundamental questions about the origins of life and how our solar system came to be. We sent OSIRIS-REx on a journey to investigate.
One of the best ways to change the trajectory of a spacecraft is by using the gravity of a planet or large moon to catapult it. It sounds like science fiction, but this type of maneuver, called a gravity assist, is a fuel-efficient way of traveling through space.
We’re not using the slingshot to speed the spacecraft, we’re doing it to change its direction. That’s because the asteroid’s orbit is tilted six degrees in comparison to Earth’s orbit. When OSIRIS-REx swings by, Earth’s gravity will lift it up and sling it toward Bennu.
Spot the spacecraft
Because at its closest approach OSIRIS-REx will only be 11,000 miles above Earth, you can see it with a backyard telescope. For most observers, the spacecraft will appear between the constellations Cetus and Pisces, but its exact position in the sky will vary by location.
After its closest approach, OSIRIS-REx flip around and look back at Earth, so here’s your chance to say hello! Take a picture of yourself or your group waving to OSIRIS-REx. Then share your photo using the hashtag #HelloOSIRISREx and tag the mission account on Twitter @OSIRISREx or Instagram @OSIRIS_REx.
To Bennu and back
In about a year from now, OSIRIS-REx will arrive at asteroid Bennu.
After it surveys and maps Bennu, OSIRIS-REx will “high-five” the asteroid with its robotic arm to collect a sample, which it will send to Earth. This asteroid sample will be the largest amount of space material transported to Earth since we brought back rocks from the Moon. High-fives all around!
If everything goes according to plan, on Sept. 24, 2023, the capsule containing the asteroid sample will make a soft landing in the Utah desert. That’s the end of the spacecraft’s seven-year-long journey to Bennu and back.
But the mission doesn’t stop there. On Earth, the sample material collected by OSIRIS-REx will be analyzed to determine the asteroid’s chemical composition. Scientists will look for organic compounds like amino acids and sugars — the building blocks for life.
Bennu is approximately 4.5 billion years old. Our solar system is 4.6 billion years old. That means that Bennu is made up of some of the oldest stuff in our solar system. So samples from Bennu could tell us more about how our solar system evolved and possibly even how life began on Earth! Learn more about asteroid Bennu, the OSIRIS-REx mission and the Earth gravity assist.
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