Just a few days ago, the American OSIRIS-REx probe hit the surface of the Bennu asteroid with a special boom and took a sample of matter from its surface to deliver it to Earth. However, not everything went according to plan.
The main goal of the OSIRIS-REx mission was to study a small 550-meter asteroid orbiting the Sun between the orbits of Venus and Mars. After the probe reached the asteroid, researchers discovered that, contrary to expectations, Determining it is not covered only with shallow regolith, but is dotted with boulders several dozen meters in size.
For this reason, astronomers have spent a lot of time looking for a suitable place from which it is relatively safe to sample matter from the surface. In the end, it was decided that the best place would be a small crater among many tall boulders.
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Probe the size of a van it had to hit a surface roughly the size of five standard parking spaces. At the moment of contact with the surface, the probe released a stream of compressed nitrogen, thus disturbing the regolith lying on the surface, and then tried to catch some of the debris raised above the surface in a special container, which then returned to Earth. At least that was the plan.
Sample too small planetoidy – wrong. Too big – also bad
The primary goal of the probe was to collect at least 60 g of material from the surface of the asteroid. However, a maximum of 2 kg of matter could fit in the container. After the first attempt to collect matter and the spacecraft moving away from the asteroid, the engineers planned to make a few rotations of the probe around its axis to determine how much matter was collected. Should the sample be too small, there are two additional nitrogen accumulators on board the probe, allowing for two additional tests. However, this will not happen anymore.
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After taking the sample the engineers took pictures of the material bin from the surface and noticed that the collected dust was escaping from it. The photos show that one of the debris created at the moment of impact or picked up from the surface blocked the bin cover, making it impossible to close it completely. Although the probe took several hundred grams of material samples from the surface, some of it escaped back from the probe.
For this reason, engineers do not intend to measure the mass of collected matter, as even more matter could escape from the reservoir during rotation. Instead, the controllers plan to place the unlocked container in a capsule as soon as possible, in which it will be sent towards the Earth. This maneuver will take place on Tuesday.
Thus, how much matter has actually been collected from the surface of the asteroid, we will find out only in 2023, when the capsule with samples will land on a training ground in Utah. Until then, it would remain a mystery. It does not change the fact that if several hundred grams were actually collected, it would be the largest sample taken from any other celestial body since the lunar times of the Apollo missions in the late 1960s and early 1970s.
It’s time to go back to Earth
Currently, the probe has started moving away from the probe at a speed of 40 cm / s. In March 2021, the engines will be launched to direct the spacecraft on its way back to Earth. The capsule with a container and samples collected on Wednesday will land on Earth in 2023.
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