How to bring asteroids to Earth?

Published: 20/5/2021

Author: Javier Pantoja

Our solar system is full of mysteries, how did it form? What is in it? How can we take advantage of its resources? How did life form? Asteroids found in our solar system may be the key to answering some of these questions, and a NASA mission launched 5 years ago aims to bring us closer to the answers.

The OSIRIS-REx mission

The OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security - Regolith Explorer) mission consists of a small spacecraft that has the objective of traveling to a near-Earth asteroid called Bennu and collecting samples to bring them back from back to Earth and be able to study them.

The name of the mission comes from its objectives, which are:

• Origins: bring back and analyze a sample from an ancient, virgin, carbon-rich asteroid
• Spectral Interpretation: provide direct observations for telescopic asteroid data
• Resource Identification: studying the chemistry and mineralogy of a primitive carbon-rich asteroid
• Safety: measuring the effect of sunlight on the orbit of a small asteroid, known as the Yarkovsky effect - the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat
• Regolith Explorer: document the regolith (loose outer material layer) at the sampling site on sub-centimeter scales.

How was it done?

The more than 7 m long, 2 m wide and 880 kg spacecraft, OSIRIS-REx, was launched from Cape Canaveral with an Atlas V 411 rocket in September 2016 and orbited the Sun for a year to recieve gravitational assistance from Earth and reach the asteroid Bennu.

In 2018 the spacecraft hit the asteroid and began a scan of its surface to identify potential sample collection sites. This process lasted a year, until it finally approached the asteroid to collect the samples using the TAGSAM.

The TAGSAM (Touch-And-Go Sample Acquisition Mechanism) is an articulated robotic arm specifically designed for this task. Confirmation was obtained in October 2020 that the samples had been successfully collected. At least 60g of the material was collected and placed in the capsule, the maximum capacity of the capsule is 2000g.

In addition to the TAGSAM, OSIRIS-REx also had several cameras, a telescope, thermal, visible light, infrared and x-ray spectrometers, and other measurement instruments that allowed it to study the surface of the asteroid.

On May 10, 2021, OSIRIS-REx changed its course, it will orbit the Sun twice and reach Earth in September 2023. The capsule, which contains the samples and has a heat shield and parachute, will separate from the spacecraft and enter the atmosphere so that it can be recovered.

After completing its main mission, OSIRIS-REx may be heading to another asteroid, as it still has plenty of fuel on board. The extent to which this extended mission is possible will be investigated this summer.

What will be done with the samples?

When the samples are received, some will be sent to laboratories in other parts of the world, but most will be studied at NASA in order to meet the mission objectives. The scientific team will catalog the sample and carry out analyzes for two years.

Not all of the sample will be analyzed in the near future, at least 75% of the sample will be saved for future research around the world and even for future generations of scientists.

It is hoped that the results of the mission can (among other things): improve theoretical models and predictions about the orbits of asteroids, helping to monitor near-Earth objects and improving our understanding of asteroids that could collide with the Earth; confirm and refute observation techniques, one of those confirmed is one that could predict the composition and presence of water in Bennu; and help scientists investigate how planets formed and how life arose.

References

https://www.nasa.gov/content/osiris-rex-mission-operations

https://www.nasa.gov/mission_pages/osiris-rex/about

https://www.nasa.gov/osiris-rex

https://www.nasa.gov/press-release/nasa-s-osiris-rex-spacecraft-heads-for-earth-with-asteroid-sample

https://www.nasa.gov/sites/default/files/atoms/files/osiris_rex_factsheet5-9.pdf

https://www.youtube.com/watch?v=DFciiHC-Faw