OSIRIS-REx returns samples to Earth, starts APEX mission

OSIRIS-REx return capsule and its parachute. Credit: NASA/Keegan Barber

Today on September 24, 2023, NASA returned its first samples from an asteroid. In 2016, OSIRIS-REx launched to visit the asteroid Bennu. However, upon closer inspection, Bennu was going to be much harder to obtain a sample from than first thought.

Bennu was thought to be mostly solid rock, with some large boulders strewn about. In reality, it was a loose conglomeration of rocks held together by mutual gravity. After reanalyzing the situation, and sending new commands to the spacecraft, OSIRIS-REx was able to obtain a sample from the asteroid

OSIRIS-REx collecting a surface sample. Credit: NASA/Goddard/University of Arizona

Because Bennu wasn't a solid object, the spacecraft sunk in as it was grabbing the sample. Using its thrusters, OSIRIS-REx was able to escape being swallowed by the asteroid. In 2021, OSIRIS-REx departed with its precious cargo.

After 2 years of travelling, OSIRIS-REx released its capsule on September 24, 2023. The spaccraft itself used its thrusters to alter its trajectory 20 minutes after releasing the capsule, so it wouldn't burn up in Earth's atmosphere. The capsule landed 2 minutes ahead of schedule, and made the most perfect landing I've ever seen. 

The OSIRIS-REx return capsule safely back on Earth. Credit: NASA

The day before, rain made the ground in the landing area slightly muddy, which helped the capsule land softly, and prevent any bouncing or skidding. The capsule was wrapped in teflon bags, and transported by helicopter to a temporary clean room. 

Right now, the capsule is being taken apart to get access to the sample arm. Once this is done, the sample head will be transported to NASA's Johnson Space Center in Texas to be opened. Initial science results will be announced on October 11.

Meanwhile, OSIRIS-REx is departing Earth on its new mission to visit the asteroid Apophis. Now known as the OSIRIS APophis EXplorer (OSIRIS-APEX), the spacecraft will visit the asteroid shortly after its close 2029 flyby of Earth.

Apophis during its 2021 flyby of Earth. Credit: NASA/JPL-Caltech and NSF/AUI/GBO

When Apophis was discovered, it was believed to have a hich chance of colliding with Earth in 2029. More data revised its orbit, and Earth is likely safe from the asteroid for a century or more. Apophis is even smaller than Bennu, and is also believed to be a rubble pile asteroid.

The Target

Mosaic of Bennu. Credit: NASA/Goddard/University of Arizona

• Date Discovered: September 11, 1999
• Designation: 101955 Bennu (1999 RQ36)
• Class: Apollo [NEO]
• Radius: 241 Meters
• Rotational Period: 4.3 Hours
• Orbital Period: 436.65 Days (1.2 Years)