Abstracts:
Prof. em. Dr. Gerhard Beutler / Prof. Dr. Adrian Jäggi (AIUB): Recent and current research at AIUB
Fundamental astronomy, the research domain of the AIUB, deals with the definition and realization of reference systems in the sky and on Earth, and with the orbital and rotational motion of the Earth, other planets, our Moon and artificial Earth satellites. Prior to the advent of the space age "only" the direction from an "Earth-fixed" telescope to objects in the sky could be measured. With the launch of artificial Earth satellites distances and distance differences to such objects and between them are accessible to measurement, as well. Here we report on "recent" activities after about 1960 and on "current" research, which includes gravity field determination of a non-rigid Earth, of the Moon, and of other planets.
Prof. Dr. Oliver Montenbruck (DLR): The Art and Science of Precise Orbit Determination
Precise orbit determination is a fundamental pillar of numerous space missions that require utmost knowledge of a spacecraft’s position in space. This applies likewise for global navigation satellite systems (GNSS) supporting terrestrial navigation and space geodesy, as well as remote sensing missions in low Earth orbit (LEO). The presentation describes the state-of-the-art and key problems faced in the precise orbit determination of GNSS satellites and LEO science missions using GNSS signals. Significant contributions made in this field by the Astronomical Institute are highlighted, and future challenges are identified.
Dr. Elmar Brockmann (swisstopo): Satellite Geodesy in Swiss Federal Surveying and related disciplines
The modern satellite geodesy completely changed the Federal Surveying in Switzerland since the 1990 years. Surveying is no longer limited to the national borders and the accuracies and speed of surveying is considerably improved. Today, surveying bases on an international collaboration and requires global data exchange of reference stations and derived global products. Since then a new reference frame for Switzerland was implemented and is made available to the users even in real-time.
The permanent networks are considered as the backbone of the geodetic infrastructure in Switzerland and proved to generate interesting results also in related disciplines, such as meteorology and tectonics.
Dr. Tim Flohrer (ESA): Space Debris – Why worry? What do we know? And how can we continue?
A total of 36,000 man-made objects larger than the size of a tennis ball are orbiting Earth, of which only about 15% are actively operated. At average impact velocities of 40,000 km/h that growing population of non-controlled objects poses a constant threat to our space infrastructure. Despite of internationally recognised space debris mitigation guidelines, technical standards, and national space regulations in place, the disposal of space systems from protected regions and the prevention of in-orbit break-ups still have a too low success rate. The risk of more collisions in space will grow further as we observe accelerating launch rates and further break-ups creating more fragments in orbit. Today, space debris is already a major issue for the design and operation of spacecraft, and while societies are becoming ever more dependent on satellites – for mobile internet, personal navigation and autonomous driving – it comes with further economic risks.
This presentation will present a short history of space debris and detail today’s challenges. Special attention will be on the contributions from AIUB and the Zimmerwald Observatory during decades of highly successful collaboration with ESA. We will introduce ESA’s goal to proceed in driving space sustainability forward through a Zero Debris approach for ESA missions by 2030.
Prof. Dr. Claude Nicollier (EPFL): Sustainability on Earth and in near-Earth space
This lecture will present the state of knowledge and current developments in the area of sustainability on Earth and in near-Earth space. It will address the issues of sustainability specifically related to the space environment, essentially because of the large amount of space debris in LEO, and of the very rapid increase in the number of satellites placed in the same region of space. The possible impact of asteroids or comet nuclei on the Earth surface will also be addressed because is clearly a sustainability issue. A significant effort is underway to insure early detection of a potential intruder, and various deflection techniques are envisioned if a probable impact on Earth is predicted. Alternatively, the estimated impact location on Earth will have to be determined early enough to organize evacuations in the area of concern.
