Microsatellites Formation Flying for In-Situ Space Debris Detection
Аuthors
1, 2, 2*, 2, 2, 2, 3, 21. La Sapienza, Rome, Italy
2. Sapienza, Italy
3. University of Bologna, Bologna, Italy
*e-mail: pfabrizio@fastwebnet.it
Abstract
Since nineties, the GAUSS (Group of Astrodynamics of the «Sapienza» University of Roma) has started UNISAT program with the aim to design, manufacture and launch University microsatellites, completely built and operated in orbit by students of the school of Aerospace engineering. In the framework of this program four satellites have been launched, two years apart one from the other, starting in 2000, and a fifth satellite is nowadays under construction.
In the same period, GAUSS has also been involved in optical space debris surveillance, participating to the IADC (Inter-Agency Space Debris Coordination Committee) observation joint campaign and, more recently, by manufacturing the first Italian observatory completely dedicated to space debris monitoring.
Combining these two experiences GAUSS students, researchers and professors are analysing the feasibility of a formation flight mission in order to detect space debris, taking advantage of an in situ observation above Earth’s atmosphere.
The paper deals with this space debris detection mission focussing on LEO orbital regime. As a matter of fact, these orbits are very crowded. Small (from 1 to 10 centimetres) debris in these orbits are difficult to detect and track by ground based optical systems. A constellation of satellites boarding optics and sensors sensible to infrared or visible radiation could monitor the LEO space debris environment through in-situ measurements. Moreover, a constellation of satellites flying in small formations permits to achieve not only debris detection but also preliminary orbit determination, thus simplifying follow-up ground base observations.
The paper gives an overview of the proposed constellation of satellites flying in small formations, highlighting main constraints, achievements and flaws of a few possible solutions.
The proposed mission configuration is made up of three satellites in a trailing formation. One satellite, the central one, will be responsible of detection and fast orbit determination of LEO objects. The other two smaller satellites will be able to track the object in order to allow a larger number of pictures and a better orbit determination.
Numerical simulations of these control strategies have been carried out taking into account different sensor accuracies; the results of some study cases are reported.
Two orbit control strategies are analyzed in order to keep the satellites within the formation constraints: the use of periodic maneuvers with chemical propulsion or a continuous counterbalance of the main perturbation (i.e. the aerodynamic one) with the use of Pulsed Plasma Thrusters.
In the end, sensors and optics feasible for this mission are analysed and two different image processing methods have been studied in order to achieve automatic in-orbit debris detection.
Download