Due to the rapidly increasing technological progress in the last decades, satellite-based infrastructure is essential for our everyday lives. This includes for instance satellite-based navigation, meteorology, and communication systems. Hence, a deterioration of the familiar services becomes immediately apparent to anybody. Since the beginning of space age in the earlier 1960s the evolution of objects in space is steadily increasing. The European Space Agency (ESA) currently counts more than 20000 objects larger than 10 cm at low Earth altitudes. This implies that, a highly accurate position of the different space objects is mandatory to reduce the number of maneuvers that must be performed by active satellites to prevent collisions with space debris.
The aim of the proposed project AROSA is to make a sustainable and innovative contribution to the space weather and space debris research areas by attempting to deal on both focal points not only individually but also in combination. Particularly during high solar activity phases, there are strong variations in the Earth's upper atmosphere that influence the orbit of satellites. In the FFG projects SWEETS (881427) and CASPER (900588) it was shown that solar eruptions like coronal mass ejections have the capability to trigger altitude losses of low Earth orbiting satellites in the order of 50 to 100 m. In this context, an extensive knowledge base regarding space weather effects on satellites has been created. However, this database is based exclusively on measurements to active satellites. This restriction shall now be removed by means of laser ranging observations to passive satellites and space debris. As a result, the higher number of observable space objects (at different altitudes) will enable an improved resolution of atmospheric variations during geomagnetic storms and lead to a better understanding of events like the Starlink event in February 2022 in which 38 satellites crashed due to a solar storm.
Another goal, that is closely related to this, is the improvement of space debris positioning. Both objectives are linked to the extent that a better orbit solution allows an improvement in density determination. Conversely, an extended knowledge about the behavior of the upper atmosphere will result in an even more accurate orbit determination process, as this strongly depends on the available force modelling capabilities. For the improvement of space debris positioning, we propose to combine laser ranging and pointing measurements. The basis for this is plate solving - a technique which uses the position of stars to allow the determination of the pointing direction of the image on the sky. The findings are intended to demonstrate other scientific laser stations that an improvement of space debris observations can be cost-effectively implemented. This would be helpful to support the highly precise but also very expensive and complex laser ranging measurements and to jointly achieve an increased accuracy in determining the position of space debris by combining the observations.
With that in mind, the project AROSA is intended to make a significant contribution to the serious issues of space safety and to intensify the collaboration between the Graz University of Technology and the Space Research Institute. This in turn would strengthen Graz as a scientific location as well as the Austrian activities regarding sustainable behavior and responsibility for the subject’s space debris and space weather.