2021-08-02

BepiColombo Optical Observation: Can help find potentially threatening asteroids

By yqqlm yqqlm

The main goal is to calculate and compare the observed flyover orbit attributes with the values ​​provided by the mission control center. The method we designed can be improved in future observation activities for natural objects that may collide with the earth.

BepiColombo Optical Observation: Can help find potentially threatening asteroids

The probe’s entry orbit is restricted The observability of the ground is only a few hours, which is about the time it is closest to the earth. The telescope network we use was developed by ESA’s Near-Earth Object Coordination Center (NEOCC), and because of its ability to quickly observe upcoming impactors, it can present a similar orbit. Our team used various instruments to successfully capture targets such as the 6ROADS Chile Telescope, the 1.0-meter Zadko Telescope in Australia, the ISON Telescope Network and the 1.2-meter Kryoneri Telescope in Corinthia, Greece.

Due to the extremely fast angular motion of the object in the sky, observation is very difficult. At a certain moment, the telescope saw the probe covering the sky twice the size of the moon every minute. This poses a challenge to the tracking ability and timing accuracy of the telescope. When taking images, each telescope moves and “tracks” the spacecraft at the predicted instantaneous speed of the target. Field stars appear in the form of trajectories, and BepiColombo itself is a point source, but only if the observation starts at the right moment. Since the detector moves very fast, any date error in the telescope image will be converted into a position error of the detector. In order to achieve an accurate measurement of 0.1 meters, the date of the image needs to have an accuracy of 100 milliseconds.

The final result is compressed into two measurable quantities, which can be directly compared with the mission control (Mission Control) quantity, the perigee distance and the time the probe is closest to the earth. If these two numbers match exactly, then our method has been proved to be successful for a long time: it calculates a more accurate prediction of the orbit of BepiColombo, and it also provides valuable insights for future observations of objects colliding with the earth:

Pure optical observation activities can provide sub-kilometer and sub-second flight trajectory information;

Similar motions will make the time and position accuracy of any colliding object into the atmosphere reach sub-km and sub-second;

Timing accuracy below 100 milliseconds is essential for recent observations;

It is possible to organize astrometric activities covering almost every continent.