Sensoris

Abstract

Satellite gravimetry missions allow to track mass transport on global scales. The main satellite constellations for the gravity recovery are the GRACE and GRACE Follow-On missions. Typically, they provide monthly gravity field solutions which at times is suf-fering from data gaps. The future MAGIC constellation shall continue the time series and improve especially the spatial sampling with a possible improvement of the temporal sampling to 5 days. For higher temporal resolutions, new mission concepts are required.

The SENSORIS constellation is being developed by the Institute of Aerospace Tech-nology (IAT) of the City University of Applied Sciences Bremen, the Centre of Applied Space Technology and Microgravity (ZARM) of the University of Bremen and is sup-ported by the DLR Institute for Satellite Geodesy and Inertial Sensing, Hanover. The purpose of the constellation is to measure the Earth's gravity field using a NewSpace approach for faster, cheaper and more flexible data acquisition for research, security and resource management. The advantage of SENSORIS lies in the ability to increase the capabilities by adding additional spacecraft at low costs; the more spacecraft make up the constellation, the more frequent data can be generated. This allows an adjustment of the size of the constellation to the prevailing economic conditions while guaranteeing that the areas of interest receive up-to-date data. It is also complementary to the MAG-IC constellation as it tackles the prevailing problem of the background modelling by providing direct observations of daily mass variations, though initially at low spatial resolution.

For the initial proof of concept, two 3U CubeSats, which are an evolution of VIBES Pioneer, will be launched, demonstrating the operational functionality. The CubeSats will be equipped with GNSS-receivers allowing the derivation of the gravity field in the high-low satellite-to-satellite tracking mode. For a fully operational constellation, at least 16 spacecraft are expected to be launched allowing to derive gravity field solutions with low spatial (approx. degree 10-15) but with high temporal resolution, e.g. daily or half-daily. We will discuss the expected performance of such a constellation in terms of grav-ity field recovery. In the future and by implementing a GRACE follow-on-like laser ranging interferometer (LRI), changing to the low-low satellite-to-satellite tracking scheme is possible and, consequently, increasing the spatial resolution, for which the development of compact LRI instruments is required.