Raising TRMM's orbit was delayed to avoid a collision with debris and also because TRMM went@into Sun Acquisition Mode at an altitude of 383km. All processes for raising TRMM's orbit were completed. TRMM is presently performing normally in a 402.5km orbit.
Standard algorithms require several modifications for operation at 400 km altitude, and TRMM standard products are unavailable during the modifications. Standard products during this term will be processed after the data release. The current boost plan and data delivery schedule are shown below.
[ Schedule of orbit raising ]
August 7, 2001 Start raising the satellite altitude
August 24, 2001 Finish raising the satellite altitude
[ Scheduled data release ]
| | Near Real-Time Product |
Standard Product |
| PR | September 3, 2001 |
February 2002 |
| TMI, VIRS | Continuous |
November 2001 |
| LIS | |
November 2001 |
[ Scheduled data release for TRMM PI* ]
| | Standard Product |
| PR | September 18, 2001 |
| TMI, VIRS, LIS | Continuous |
* : Researchers selected in the 3rd TRMM Research Announcement.
[ Impacts of raising the satellite altitude ]
- Satellite bus, TRMM Microwave Imager (TMI), Visible Infrared Scanner (VIRS), and Lightning Imaging Sensor (LIS)**
NASA confirmed the satellite and above listed sensors would be reliable after the change of orbit altitude.
** : The Clouds and the Earth's Radiant Energy System (CERES) ceased observation in June 2001.
- Impacts of raising the satellite altitude for Precipitation Radar (PR) are;
- Degradation of received power,
- Possible noise interference in the data by mismatch of transmit-to-receive pulse,
- Possible degradation of observable echo top height.
NASDA concluded that these impacts will not serious by influence research using PR data.
Please see the following documents for further information.