CHAMP Mission 5 Years in Orbit

Abstract

Summary. In the summer of 2000 the geo-research satellite CHAMP was launched into orbit. Its innovative payload arrangement and its low injection altitude allow CHAMP to simultaneously collect almost uninterrupted measurement series relating to the Earth gravity and magnetic fields at low altitude. In addition, CHAMP sounds the neutral atmosphere and ionosphere using GPS observations onboard. After 60 months in orbit one arrives at a very positive conclusion for the CHAMP mission. The CHAMP satellite and its instruments have been operated almost uninterruptedly since launch. The great performance of the satellite subsystems and of the mission operation specialists has made it possible to keep CHAMP in the science operation mode for most of the time and in addition to lift its orbit two times. After a series of calibration and validation activities in the course of the mission, which included a number of onboard software updates and parameter adjustments, CHAMP has been providing excellent measurements from its state of the art instruments for now more than 4 years. The effective and steadily functioning of the CHAMP Science Data System and the supporting tracking networks has made it possible to provide large quantities of pre-processed data, precision data products and auxiliary information to hundreds of registered users in an almost uninterrupted manner. This was only possible due to the funding of the project DACH (CHAMP Data Acquisition and Data Use) within the 'GEOTECHNOLOGIEN' R+D programme of the BMBF. With the orbit altitude being presently about 60 km higher than originally planned for mid 2005, CHAMP will very likely orbit the Earth for another 3 years at quite low altitude. This mission extension at low altitude will make CHAMP a pioneering long-duration mission for geo-potential research and sounding of the atmosphere.

Post-processing scheme for modelling the lithospheric magnetic field

“…To the authors' knowledge, such techniques have never been applied to magnetic models, although we should note the attempt to estimate the model covariance matrix in Lowes and Olsen (2004). In this manuscript we present and apply such a post-processing scheme for a model of the magnetic lithospheric field derived from ten years of CHAMP satellite data (Reigber et al, 2005). Although we are presenting this work from its application side, it has deeper roots: We investigated how typical noise correlated patterns leak, through a least squares fitting process, inside a magnetic model of the lithospheric field.…”

Evaluation of the DTM-2009 thermosphere model for benchmarking purposes

“…The total density data 2.1.1. Total density inferred from accelerometer measurements on CHAMP, GRACE, and AE-C/E Total neutral densities are derived from accelerometer measurements on the Challenging Mini-Satellite Payload (CHAMP; Reigber et al 1996) in the altitude range 450-250 km, and the Gravity Recovery and Climate Experiment (GRACE; Tapley et al 2004) near 490 km altitude using the methodology described in Bruinsma et al (2004). The CHAMP data set used in this study covers the period 20/05/2001 through 2/9/2010, i.e.…”

“…Specifically, model bias and precision as a function of altitude, latitude, local solar time, season, and solar-and geomagnetic activity are currently only approximately known. A detailed evaluation can actually be performed only recently thanks to the high-resolution total density data inferred from CHAMP (Reigber et al 1996) and GRACE (Tapley et al 2004) accelerometer measurements over almost a full solar cycle. These density data sets only allow the fine analysis of the latitudinal structure per-orbit (about 95 min) basis, and from pole-to-pole.…”

Constraint on Intermediate-Range Gravity From Earth–satellite and Lunar Orbiter Measurements, and Lunar Laser Ranging

“…According to (15), for a given λ in the range 1.2 × 10 7 m − 3.8 × 10 8 m, the α parameter of the α − µ model is constrained as in Fig. 3.…”