| Date: | 2000-06-30 01:19:00 | |
| Sender: | Mike Pearlman, Secretary, ILRS Central Bureau <Mike Pearlman <mpearlman@cfa.harvard.edu>> | |
| Subject: | [SLR-Mail] No. 624: CHAMP Launch 7/15/00 - Get Ready | |
| Author: | Mike Pearlman, Secretary, ILRS Central Bureau | |
| Content: | ******************************************************************************** SLR Electronic Mail 2000-06-30 01:19:00 UTC Message No. 624 ******************************************************************************** Author: Mike Pearlman, Secretary, ILRS Central Bureau Subject: CHAMP Launch 7/15/00 - Get Ready Dear Colleagues: The launch of the new satellite, the CHAllenging Mini-Satellite Payload for geoscience and application (CHAMP) is planned for July 15, 2000 at 12:00 GMT. The ILRS Governing Board has approved tracking support for this satellite and requests the cooperation of the Global SLR Network. A detailed description of the CHAMP satellite and mission is available at the GFZ web site: http://op.gfz-potsdam.de/champ/ CHAMP is a German small satellite mission for geoscientific and atmospheric research and applications, managed by GFZ. With its multifunctional and complementary payload components (magnetometer, accelerometer, star sensor, GPS receiver, laser retroreflector, ion drift meter) and its orbit characteristics (near polar, low altitude, long duration), CHAMP will generate for the first time precise, simultaneous gravity and magnetic field measurements over a 5 year period. This will allow us to detect both the spatial and temporal components in both fields. We anticipate that the CHAMP mission will open a new era in geopotential research and will become a significant contributor to the Decade of Geopotentials. CHAMP will also perform radio occultation measurements using onboard instruments and infrastructure on the ground. This will be a pilot mission for the use of space-borne GPS observations for atmospheric and ionospheric research and applications in weather prediction and space weather monitoring. Key mission parameters include: Sponsor: GeoForschungs Zentrum (GFZ) Potsdam, Germany Expected Life: 5 years SLR Application: precision orbit determination and geodesy COSPAR ID: 0099999 (temporary, until assignment after launch) SIC: 8002 NORAD SSC Code: to be assigned after launch Launch Date: July 15, 2000 at 12:00:00 GMT Launch Vehicle: Russian COSMOS Orbit: circular Inclination: 87.3 degrees Eccentricity: 0.001 Altitude: 460 km Period: 99 minutes Array Diameter: 5 cm Array Shape: rectangular Reflectors: 4 corner cubes Normal Point Bin Size: 5 sec The laser retroreflector array consists of 4 prisms, but only one prism should be visible to an SLR ground station at a time. The SLR data will be used for: * Precise orbit determination in connection with GPS for gravity field recovery * Calibration of the on-board microwave orbit determination system (GPS) * Technological experiments (two-color ranging) The ILRS will coordinate the global SLR station scheduling and support during all critical phases of the CHAMP mission. Prior to launch, preliminary orbit predictions will be made available by GFZ. Inter-range Vectors (IRVs), Smithsonian Astrophysical Observatory (SAO) elements and two line elements (TLEs) will be the primary orbit determination products available to the SLR community. These predictions will be distributed to the EDC and the CDDIS for global access. Following orbital deployment of CHAMP, GFZ will generate and distribute acquisition data twice per day through the EDC and the CDDIS. The times of these distributions will depend on the flow of GPS data to the Data Centers. The standard acquisition data will be Tuned Inter-Range Vectors (TIV) and drag functions. The rapid flow of data to the Data Centers and the frequent updating of orbital solutions will support the generation of high accuracy predictions required for the daylight tracking of CHAMP. I. Launch and Early Orbit Phase Immediately following orbital deployment on July 15, 2000, a one month intensive tracking phase will commence. The on-board GPS will be inactive during this phase, so it is essential that we capture the maximum possible number of CHAMP passes with SLR. SLR data will provide the only tracking data to generate precise orbits during this critical phase. The ILRS Network will place CHAMP at the highest satellite scheduling priority during this two-week period. II. Commissioning Phase For the next 8 months following launch, CHAMP will remain at very high ILRS tracking priority. During this period the onboard GPS, payload instrumentation, and all other satellite functions will be reviewed, calibrated and validated. III. Nominal Operation Phase Upon the verification of the onboard systems, CHAMP will be prioritized as an active mission on the ILRS tracking priority list. With its very low orbital altitude, it will continue at very high priority throughout its lifetime. IV. Orbit Maneuver Phase To maintain the correct orbit for CHAMP, a series of intermittent satellite maneuvers will be required. Advanced electronic notification of all anticipated maneuvers will be provided by the GFZ and disseminated to the EDC, CDDIS and the ILRS. This is a very important mission and it depends upon the support of our tracking network. We need heavy tracking support and the data must be submitted as soon as possible to the Data Centers. PLEASE MAKE EVERY EFFORT TO MAKE THIS A SUCCESS. If you have any questions or comments, regarding the SLR support of the CHAMP mission, please contact the ILRS Central Bureau. Very best regards, Mike Pearlman Dr. Michael R. Pearlman Harvard-Smithsonian Center for Astrophysics 60 Garden St. Cambridge MA 02138 tel. (617) 495-7481 fax. (617) 495-7105 e-mail. mpearlman@cfa.harvard.edu From: ”Mike Pearlman” ******************************************************************************** |