General

Tonight CHAMP goes into its 100th revolution. The commissioning will be continued in order to start routine operation in calendar week 31. Because of the positive overall situation, there won't be a CHAMP Bulletin during the week-end.

Satellite bus systems

Power: The battery charge level is stable.

Thermal system: All temperatures are within the designed range and stable over the orbit.

Attitude and orbit control: Attitude control and gas consumption show nominal values. Into the investigation of the error leading to the failure of the coarse earth/sun sensors (see Bulletin No. 2) the examination of possible overheating phenomena is included.

Onboard data handling system: The onboard processor and software run correctly.

Telemetric system: A stable transmission from/to the satellite is secured.

Scientific instruments

More detailed analyses of the magnetic field measurements confirm the excellent magnetic cleanliness of the CHAMP satellite. Recordings of the laser ranging station Graz confirm a surprisingly low measurement uncertainty (caused by the laser reflector) of less then 5 mm.

Flight operations

Flight operations run nominally. NASA generously continues its satellite control support.

Satellite orbit

The CHAMP orbit is intensively tracked and with very high accuracy being recovered.

The most important average orbit paramerters are:

• Semi-major axis = 6824.287 km
• Eccentricity = 0.004
• Inclination = 87.275 degrees
• Perigee Height = 418.23 km
• Apogee Height = 474.05 km
• Sec. Motion Perigee = -3.88 degrees/day
• Sec. Motion Node = -0.37 degrees/day
• Kepler Period = 93.51 minutes

signed:
Christoph Reigber
CHAMP Project Director
GeoForschungsZentrum Potsdam

signed:
Peter Mühlbauer
CHAMP Mission Operations Director
German Space Operations Center of the DLR