A Touchdown On An Asteroid

Oct 27, 2020 By Christina K.
Airaphta's picture

While we’re all familiar with spacecraft landings on the moon and Mars, when was the last time you heard of a spacecraft land on an asteroid? Probably never, since it has not happened… until now. 

On October 20, 2020, NASA scientists celebrated the successful landing of spacecraft Osiris-Rex on asteroid Bennu.

It will take at least a week for scientists to know what kinds of samples or how much was collected, and whether they will need to try again. If everything goes as planned OSIRIS-REx will bring back space samples in 2023. 

The Landing

The program to launch the OSIRIS-REx started in 2016. After a two-month delay caused by the COVID-19 epidemic, NASA scientists began OSIRIS-REx’s landing. 

The NASA team behind the landing refers to the sample collection mission as Touch-and-Go (TAG). Osiris-Rex had to make a brief landing on the Nightingale crater, a landing spot the spacecraft found after two years of orbiting Bennu. The team hopes to bring back at least 60 g of samples.

The event was 4.5 hours of anxiety for the NASA team. OSIRIS-REx was more than 200 million miles away. This meant there was a communication delay of 18.5 minutes, making live commands from Earth near-impossible. OSIRIS-REx had to land, collect samples, and leave all by itself. And asteroid Bennu, being just 1,670 ft wide, did not have enough gravity for the spacecraft to make a proper landing.

Instead, OSIRIS-REx used its 11 ft long robot arm (known as the Touch-And-Go Sample Acquisition Mechanism, or TAGSAM). After reaching Bennu’s surface, TAGSAM released a burst of nitrogen gas to disturb the dust. Then, the TAGASM sucked up the stirred-up sediment, and the spacecraft carefully made its way off of the asteroid.

The Significance of Bennu

While it is not impressive in size, Bennu’s age is what makes it interesting to NASA. It is 4.5 billion years old. Because Bennu is so old, it may contain molecules present during the formation of the solar system and Earth. This makes Bennu significant in retelling the history of our planet and solar system. 

Bennu is important not just for the past, but for our future, as well. The asteroid has a 1-in-2700 chance of hitting Earth. OSIRIS-REx’s observations will allow scientists to better predict Bennu's path.

On the bright side, scientists can study Bennu to decide if it is possible to mine the asteroid’s surface during space explorations. Bennu, among other asteroids, is rich in rare metals and, surprisingly, water. While space jewelry sounds interesting, NASA scientists are more interested in collecting water. If astronauts can extract water for drinking or making breathable air, they can make space more accessible to humans.

OSIRIS-REx’s landing is a major event that will pave the way for more deep space exploration. To continue studying space and asteroids, NASA plans to launch three more asteroid trips within the next two years.

Sources: Guardian, NYTimes, CNN, NASA