Satellites move in orbit at speeds of thousands of kilometers per hour, and without precise information about it, there is a high probability of collisions, or at least a constant expectation of collisions, which could be even worse. Measuring this value is achieved in various ways, all of which are quite complex. Scientists from the United States have come up with a simple and reliable speedometer for spacecraft, which will be especially useful in missions to other planets in the system.
Image source: Los Alamos National Laboratory
Today, the speeds and orbits of spacecraft near the Earth and other planets are calculated using radar observation data. In Earth orbit, it is possible to measure the speed using onboard GPS devices using atomic clocks. All of these methods require complex calculations and constant observation data, which is not always possible depending on the complexity of the orbit and the location of the tracking stations. Therefore, a simple onboard device for measuring the speed of a specific device, regardless of the presence of an observer and communication channels, is very good and will certainly facilitate navigation in the future.
The space speedometer was developed by specialists from the Los Alamos National Laboratory and the United States Air Force Academy. These are two identical plasma sensors in the form of multilayer plasma spectrometers. One sensor is installed forward along the ship’s course, and the second is placed in the back of the satellite and oriented in the opposite direction.
As the satellite moves along the Earth’s orbit or around other planets, it will encounter many plasma particles – ions of atmospheric atoms. These ions will also bombard the front sensor, which will be able to record the density and energy of the ions. The rear sensor, directed in the opposite direction, will obviously be bombarded by ions with lower energies and in a significantly smaller volume – only those that catch up with the satellite or hit the sensor from the side. By calibrating both sensors, it is possible to obtain an accurate reading of the satellite’s speed.
«[“A spacecraft speedometer can provide critical measurements of the spacecraft’s speed on board in real time,” said Carlos Maldonado of Los Alamos, the project’s principal investigator. “These measurements are essential to improving our ability to accurately predict the satellites’ locations so we can maneuver and avoid other active satellites and debris.”
The developed device has been tested in space on the ISS. Currently, commercial partners are being sought to launch the device into production.