Nachhaltigkeit: ein kulturelles, bisher aber chancenloses Wirtschaftsziel

"In dem Gegensatz von 'schwacher' und 'starker' Nachhaltigkeit geht die schwache nicht weit genug zum Schutz der Natur, die 'starke' hingegen zu weit, weil sie der Wirtschaft unnötig scharfe Grenzen setzen würde. Sinnvoller wäre das positive Ziel, die Wirtschaft zu rekultivieren. Dem steht allerdings das Dreisäulentheorem der Gleichgewichtigkeit ökologischer, sozialer und ökonomischer Ziele entgegen. Hierzu wird eine radikale Anhebung der Erbschaftssteuer vorgeschlagen." (Autorenreferat)"'Weak sustainability' is as clear as economics but cannot sustain nature and would lead us into a world of swimming pools instead of beaches and fitness centres instead of walking paths. 'Strong sustainability', on the other hand, is too strong a limitation and politically weak because it sets limits instead of conceiving better goals such as re-cultivating the economy. Cultural sustainability is pointed out as a positive orientation. This, however, is not compatible with giving equal weight so ecological, social, and economic goals because capital is not aging. A solution can be found in radical increased inheritance taxes." (author's abstract

Resistive-based micro-kelvin temperature resolution for ultra-stable space experiments

High precision temperature measurements are a transversal need in a wide area of physical experiments. Space-borne gravitational wave detectors are a particularly challenging case, requiring both high precision and high stability in temperature measurement. In this contribution, we present a design able to reach 1 µK/Hz---v in most of the measuring band down to 1 mHz, and reaching 20 µK/Hz---v at 0.1 mHz. The scheme is based on resistive sensors in a Wheatstone bridge configuration which is AC modulated to minimize the 1/f noise. As a part of our study, we include the design of a test bench able to guarantee the high stability environment required for measurements. We show experimental results characterising both the test bench and the read-out, and discuss potential noise sources that may limit our measurement.Peer ReviewedPostprint (published version

Resistive-Based Micro-Kelvin Temperature Resolution for Ultra-Stable Space Experiments

High precision temperature measurements are a transversal need in a wide area of physical experiments. Space-borne gravitational wave detectors are a particularly challenging case, requiring both high precision and high stability in temperature measurement. In this contribution, we present a design able to reach 1 μK/(squareroot of)Hz in most of the measuring band down to 1 mHz, and reaching 20 μK/(squarerooot of) Hz at 0.1 mHz. The scheme is based on resistive sensors in a Wheatstone bridge configuration which is AC modulated to minimize the 1/f noise. As a part of our study, we include the design of a test bench able to guarantee the high stability environment required for measurements. We show experimental results characterising both the test bench and the read-out, and discuss potential noise sources that may limit our measurement

COMPASSO mission and its iodine clock: outline of the clock design

One of the limiting factors for GNSS geolocation capabilities is the clock technology deployed on the satellites and the knowledge of the satellite position. Consequently, there are numerous ongoing efforts to improve the stability of space-deployable clocks for next-generation GNSS. The COMPASSO mission is a German Aerospace Center (DLR) project to demonstrate high-performance quantum optical technologies in space with two laser-based absolute frequency references, a frequency comb and a laser communication and ranging terminal establishing a link with the ground station located in Oberpfaffenhofen, Germany. A successful mission will strongly improve the timing stability of space-deployable clocks, demonstrate time transfer between different clocks and allow for ranging in the mm-range. Thus, the technology is a strong candidate for future GNSS satellite clocks and offers possibilities for novel satellite system architectures and can improve the performance of scientific instruments as well. The COMPASSO payload will be delivered to the international space station in 2025 for a mission time of 2 years. In this article, we will highlight the key systems and functionalities of COMPASSO, with the focus set to the absolute frequency references

In-Orbit Performance of the GRACE Follow-on Laser Ranging Interferometer

The Laser Ranging Interferometer (LRI) instrument on the Gravity Recovery and Climate Experiment (GRACE) Follow-On mission has provided the first laser interferometric range measurements between remote spacecraft, separated by approximately 220 km. Autonomous controls that lock the laser frequency to a cavity reference and establish the 5 degrees of freedom two-way laser link between remote spacecraft succeeded on the first attempt. Active beam pointing based on differential wave front sensing compensates spacecraft attitude fluctuations. The LRI has operated continuously without breaks in phase tracking for more than 50 days, and has shown biased range measurements similar to the primary ranging instrument based on microwaves, but with much less noise at a level of 1 nm/Hz at Fourier frequencies above 100 mHz. © 2019 authors. Published by the American Physical Society

Einheit der Natur – Entwurf der Geschichte. Begegnungen mit Carl Friedrich von Weizsäcker

Krohn W, Meyer-Abich K-M, eds. Einheit der Natur – Entwurf der Geschichte. Begegnungen mit Carl Friedrich von Weizsäcker. München: Carl Hanser Verlag; 1997