Nasa’s space probe Osiris-Rex is returning to Earth with asteroid debris


In August 2023, Nasa conducted an exercise in which they dropped a capsule similar to the one from Osiris-Rex from a high altitude.

After just over seven years, the space probe Osiris-Rex is now returning to Earth. It carries with it material from the asteroid Bennu that hopefully contains answers to questions about the youth of the solar system.




Name: Osiris-Rex stands for “The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer”

Purpose: Collect soil samples from asteroid Bennu

Pulp: 2,110 kg

Launch: Osiris-Rex was launched on September 8, 2016 from Cape Canaveral

Source: NASA

Asteroids are made up of the material left over when the Sun and the planets formed – so they can provide details about the early days of the Solar System.

With that in mind, Nasa launched the Osiris-Rex space probe in 2016 with the goal of reaching the relatively nearby asteroid Bennu. After getting there, orbiting the asteroid for two years and then collecting a soil sample, the craft has now almost completed the journey home.

When the space probe is 102,000 kilometers from Earth, it will release a capsule containing the collected soil sample. The capsule will then enter the atmosphere to finally land using a parachute.

Nasa expects the asteroid debris to land within the US defense areas in a desert in Utah, USA, Sunday, September 24 at 16:55 Swedish time.

A composite of 12 images taken by the PolyCam camera on board Osiris-Rex shows the asteroid Bennu from 24 kilometers high.

A rocket launch

Osiris-Rex was launched by an Atlas V rocket in September 2016.

Third mission to retrieve material from an asteroid

If all goes according to plan, Osiris-Rex will be the third space probe to deliver material from an asteroid. Japan has previously managed to visit the asteroids Itokawa and Ryugu with the space probes Hayabusa 1 and 2.

But the hope, and the expectation, is that Nasa’s space probe has brought back more material than the Japanese managed to capture. The Hayabusa 1 delivered all around 1,500 dust particlesand the Hayabusa 2 brought more with it 5.4 grams. Osiris-Rex is believed to carry around with him 250 grams from Bennu.

The carbon-rich asteroid has been more or less untouched for 4.5 billion years and scientists hope that the sample will be able to say something about how the planets in the solar system developed. Due to its age, the asteroid sample may also consist of material with organic molecules that existed when life appeared on Earth.

Osiris-Rex collected material from Bennu and then quickly backed away from the asteroid again.

Psyche is NASA’s next asteroid mission


The scientific instruments on board Osiris-Rex:

Osiris-Rex has three cameras, PolyCam, MapCam, SamCam which together are called Ocams. The probe also has a laser altimeter called Ola and three different spectrometers called Ovirs, Otes and Rexis. Also on the trip to Bennu was the collection mechanism Tagsam (Touch-And-Go Sample Acquisition Mechanism).

Source: NASA

When the asteroid Bennu is closest to us in its orbit around the Sun, it is around 300,000 km away, which is closer than the Moon which is 384,400 km away. It comes this close once every six years. According to Nasa, the asteroid’s orbit may change, and they state that the risk is 1 in 2,700 that it may collide with Earth between the year 2175 and the year 2199.

In addition to possible organic molecules, the asteroid is also believed to be richer in platinum and gold compared to the Earth’s crust. Due to the fact that asteroids can consist of valuable metals, they are of interest for possible mining in the future.

An asteroid believed to be almost entirely metal is 16 Psyche, the sixteenth asteroid ever discovered. Nasa will investigate the asteroid more closely with a space probe of the same name, which will be launched in early October.


For Osiris-Rex, the space adventure is not over. After the package of material is released, the space probe is given a new name and a new target while it starts its engines to avoid being pulled in towards Earth. Osiris-Apex (Osiris-Apophis explorer) will in the future investigate the asteroid Apophis, a 370 meter diameter large object, which will pass 32,000 kilometers from Earth in 2029.

People in the desert and a capsule on the ground.

Nasa conducted an exercise in August 2023 ahead of this weekend’s gravel delivery.