This artist’s concept shows the OSIRIS-REx spacecraft approaching the asteroid Bennu. Image: NASA
It has been another moment of success for NASA as its OSIRIS-REx robotic explorer arrives at the asteroid Bennu.
Just a few years ago, the European Space Agency (ESA) achieved a major first in space exploration by landing a spacecraft on the surface of a comet, albeit it with a bit of a bump.
Now, NASA is one step closer towards achieving another first, by using a spacecraft called OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) to collect a sample of an asteroid and return it to Earth. The asteroid, dubbed Bennu, is no piece of space junk, as its predicted trajectory shows it coming within a close shave of Earth 150 years from now.
Launched two years ago, OSIRIS-REx yesterday evening (3 December) announced its arrival approximately 19km from the large car-sized object, as it slowly begins edging closer until it enters the object’s orbit on New Year’s Eve. According to The Guardian, this will make it the smallest object ever orbited by a spacecraft.
Once it enters orbit, it will spend close to a year surveying the asteroid with five scientific instruments, with the goal of selecting a location that is safe and scientifically interesting to collect the sample. It will then begin the 122m km journey home with the collected sample to eventually reach Earth in September 2023.
To mark the arrival, NASA has now released a GIF of its gradual approach of the asteroid, growing from a small dot to the large diamond-shaped object we see today.
OSIRIS-REx’s view of Bennu during the final phase of its journey to the asteroid. From 17 August through 27 November, the spacecraft’s camera imaged Bennu almost daily as the spacecraft travelled 2.2m km toward the asteroid. Image: NASA’s Goddard Space Flight Center/University of Arizona
Major space haul
With the aim of bringing back 60g of dust and gravel to Earth, it would represent the biggest haul of material from space since the Apollo astronauts returned with moon samples decades ago. NASA’s aim is to analyse the samples to learn more about the source of water in the universe and origins of organic molecules.
It will also be a major fact-finding mission for our efforts to better understand the Yarkovsky effect, a non-gravitational force that could change an asteroid’s orbit. By measuring Bennu, we could help predict whether it could indeed collide with Earth, leaving a big crater in its wake.
In the meantime, the Japanese space agency JAXA aims to beat NASA to the punch after the arrival of its own spacecraft last June to another asteroid called Ryugu. While expected to return an asteroid sample far smaller than what OSIRIS-REx will bring back, it will arrive almost three years earlier, in December 2020.
