Last Tuesday, NASA’s OSIRIS-REx spacecraft managed to touch the asteroid Bennu with its robotic arm in order to collect dust and pebbles from its surface and bring them to Earth in 2023. This new success from the US space agency is not only successful. for touching an asteroid for the first time, but also for offering experts new clues about the origin of life on Earth.
Javier Licandro, research coordinator of the Canary Islands Institute of Astrophysics (IAC) is part of the scientific team of OSIRIS-REx and he attended, together with his colleagues, telematically, the live meeting of the maneuver. Licandro has been part of the team since 2011, when the mission began to take shape.
What has been the contribution of the Instituto de Astrofísica de Canarias to the mission of the OSIRIS-REx spacecraft? The institute works on images from the ship’s cameras. We take the interpretation of the color images that the ship takes with the cameras called SamCam but we also collaborate with the interpretation of the images of the other cameras, called OCAMS, and in their calibration. In summary, we collaborate in the calibration of the images and in the elaboration of all the asteroid maps.
- Astrophysical researcher
What is the main objective of the OSIRIS mission? Take samples and bring them to earth from an asteroid of the primitive type, as in the asteroid Ryugu mission of the Japanese probe. Why this type of asteroids? Because they are composed of the most primitive material that we can find in asteroids.
— NASA’s OSIRIS-REx (@OSIRISREx) October 20, 2020
What characteristics do Bennu-type asteroids have that make them suitable for this mission and study? Asteroids have formed in the early stages of the Solar System, they have become larger and larger bodies from accumulating small grains of dust and then larger stones. Most of them ended up being part of the planets, that is why we usually say that asteroids are the ‘nails’ that survived their formation.
When the material accumulates in a very large volume, gravity itself exerts pressure on the materials that are there and they are transformed. The material squeezes, melts and many of its properties are lost, however, these asteroids have not had enough pressure for the material to transform too much. They are practically as the material was when the Sun was forming, in the early stages.
So is this material a window into the past of the Solar System? Bringing this material allows us to study very primitive material. We know the interest of these asteroids for pieces of them that have fallen to Earth called carbonaceous chondrites, which are meteorites that contain abundant amounts of mineral water and complex organic molecules, several dozen different amino acids have even been found. When these pieces of asteroids collide with the Earth, they first go through the atmosphere and there 95% of their composition is lost, they practically disarm. Right now what we have achieved was to collect a sample of a material that would not have survived entering the atmosphere, so if we have already found extremely interesting things in the meteorites of these asteroids, we hope to find even more interesting things in a material that otherwise it would not reach Earth.
So, is it already certain that the sample collection has been a success or do we have to wait to see more images to know if enough has been collected? From the images seen from the test shot, it is very likely that we have managed to gather the necessary material. The images show that the collector perfectly touches the surface, also goes a couple of centimeters deep, blows the nitrogen it was carrying and raises a lot of dust. Necessarily a lot of that powder must have entered the container, since this has a very simple operation, when there is pressure, a lid opens it allows the material to enter, once that pressure of the nitrogen blast stops, it closes. There is no strange mechanism, I would bet we did put it together.
The launch occurred in September 2016, arrived at Bennu in 2018, after collecting samples, what is the next phase of the mission? Right now we are going to see the amount that has been collected, if enough has been collected, 60 grams or more, we will not try to repeat the maneuver again. Anyway, we are going to continue studying Bennu for a few more months. In 2021 the return maneuver will begin and the spacecraft returns to Earth in 2023 and drops the sealed and vacuum capsule by parachute in the Utah desert where the team will be waiting.
The collection of samples in Bennu has been difficult due to the amount of craters and rocks it has, have there been any problems in the maneuver called ‘Touch and Go’ that you have had to perform? Yes, the maneuver has been extremely dangerous and it was more so than we thought before reaching the asteroid. The idea that people had of this type of object was that they were covered with fine dust, however, we have found the opposite, they are covered with stones on stones. You run a lot of risk, first because it is a safe system to collect in the sand on the beach so to speak and second because you run the risk of breaking the system with extreme ease. Hitting 300 million kilometers as it was hit, at the planned site, with just one meter where it was planned to land is an incredible milestone that was achieved with a lot of work to recognize the region by the team. The truth is that we originally designed it to hit a 50 meter diameter circle, and we didn’t find a single place of that size that wasn’t filled with stones. In this case, the one that was finally chosen was 16 meters in diameter, the maneuver was in a much smaller area than planned, however the programming could be adjusted perfectly.
As it is an asteroid so old that its surface has remained virtually unchanged for millions of years, how could your research help in the study of the origin of life on Earth? Well, it will give us information regarding the type of complex organics that we can find in this type of object. On the other hand, it can allow us to know how much water they must have had when the Earth was formed since there is a consensus that most of our planet’s water comes from the impacts of these asteroids and comets since our planet was an extremely dry and besides, the surface was very hot and there was no way there would be physical water on its surface. We want to see what else these asteroids contain that may have provided the essential material for our planet to develop the reality of life that it has today.
Undoubtedly it can solve doubts at the level of the origin of life, but on the other hand, can these asteroids be a danger to life on Earth? It is one of the potentially dangerous asteroids, the type that can collide with the Earth and cause a disaster of global proportions, so studying structurally how they are will allow us strategies to divert them in the future.