 |
Vegetation Canopy Lidar (VCL) |  |
| - Current Status - | ||
| Updated January 26, 2001 |
|
Vegetation Canopy Lidar (VCL) | |
| - Current Status - | ||
| Updated January 26, 2001 |
The VCL mission team is working with NASA headquarters to obtain the funding necessary to complete the VCL mission. The launch will most likely be delayed until early 2003.
The flight spacecraft bus is currently located at the Orbital Sciences Corporation facility in Dulles, VA, and successfully completed an Integrated Systems Test (IST) in December 2000. The IST is a rigorous test of the satellite hardware and software. The satellite was fully populated with flight hardware except for the Mains Power Controllers (MPCs), star tracker, and Global Positioning System (GPS) receiver. Engineering model MPCs, which are fully functional, were used for the IST. MPC flight units will be completed and installed on the spacecraft in April. A spare star tracker from another GSFC program will be utilized, upon completion of an interface change. We are working with NASA's Jet Propulsion Laboratory (JPL) in Pasadena, CA to incorporate reliability enhancements into our existing GPS receiver.
Development of the Multi-Beam Laser Altimeter (MBLA) instrument making excellent progress. Being built by NASA's Goddard Space Flight Center (GSFC), significant portions of the MBLA (optical bench, detectors, radiators, primary reflector, and secondary reflector) are complete and available for Instrument Integration and Test (I&T). The greatest technical challenges of the VCL mission are the laser transmitters (LTs). The LT flight design has successfully completed performance characterization testing, followed by successful completion of a 50 hour (43.6E6 shots) performance "burn-in" test with no degradation in performance. The same unit will be used to complete environmental qualification this Spring. In the meantime, assembly has begun on three flight LTs and a flight spare. Design of radiation hardened Data Electronics (DE) has been completed and assembly of the flight hardware is underway.
Elements of the VCL Ground System to be developed include the VCL Control Center (VCC) and VCL Data Center (VDC), and are being built by Omitron, Inc. and Raytheon, respectively. Both of these will be located at the University of Maryland, and are well underway. Extensive command and telemetry database development has been completed. VCC hardware and software were successfully used to test the spacecraft during the IST.
VCL's Athena I launch vehicle was transferred to the Air Force in November 2000. Both a shared Delta II and a dedicated Taurus are under consideration as replacement launch vehicles. Technically, VCL can be launched by either of these. An assessment shows the Taurus having less impact on the satellite design. The Launch Readiness Date (LRD) under consideration is May 2003.