David F. Everett
NASA/Goddard Space Flight Center, Code 730, Greenbelt, MD 20771
(301) 286-1596, David.F.Everett.1@gsfc.nasa.gov
Thomas E. Correll
NASA/Goddard Space Flight Center, Code 573, Greenbelt, MD 20771
(301) 286-6047, Thomas.E.Correll.1@gsfc.nasa.gov
Scott Schick
Space Dynamics Laboratory, Logan, UT
(435) 797-4426, sschick@sdl.usu.edu
Kimberly D. Brown
NASA/Goddard Space Flight Center, Code 545, Greenbelt, MD 20771
(301) 286-2627, Kimberly.D.Brown.1@gsfc.nasa.gov
Abstract
The Wide Field Infrared Explorer was developed to perform astronomy using a cryogenically cooled infrared telescope. Shortly after launch, rapid venting of the cryogen, caused by an untimely cover removal, sent the spacecraft into an uncontrollable spin which exceeded 60 revolutions per minute. Over the next week, the WIRE team developed a plan and successfully executed the procedures necessary to de-spin the spacecraft and gain attitude control, but the cryogen for cooling the instrument was depleted. The recovery of the spacecraft enabled a thorough checkout of most of the subsystems, including the validation of several new technologies. Although the primary science mission was lost, WIRE is making breakthrough astroseismology measurements using its star tracker. This paper describes the recovery of the WIRE spacecraft and the performance of its key technologies, including the two-stage solid-hydrogen cryostat, an all-bonded graphite-composite structure with K-1100 radiator panels, composite support struts, a dual-junction gallium arsenide solar array module, a concentrator solar array module, and a 300 Mbyte solid-state recorder.
Table of Contents
I. Introduction
II. Mishap Related Operations
A. Launch
B. De-spin and RecoveryIII. Performance of Key/New Technologies
A. Cryostat
1. Ground Testing
2. Launch Site Operations
3. On-Orbit Performance
4. Cryostat SummaryB. Thermal System
1. Overview WIRE Thermal Model
2. Flight Validation
3. Thermal System SummaryC. Composite Structure
D. Power System
E. Earth Sensor
F. Data System
G. Ground SystemIV. Science and Experiments
A. Astroseismology
B. WIRE Test BedV. Summary
List of Figures
Figure 1. The WIRE spacecraft as seen from the anti-sun side.
Figure 2. Decrease in Spin Rate During Recovery
Figure 3. WIRE Instrument Showing Telescope and Two-Stage Cryostat
Figure 4. Hydrogen Vapor Pressure
Figure 5. Flight Temperatures Showing Primary and Focal Plane Cooling Below 15 Kelvin
Figure 6. WIRE TSS Internal Geometric Model
Figure 7. WIRE TSS External Geometric Model
Figure 8. Qualification, Prediction, and Actual Temperature Extremes for WIRE Components
Figure 9. Mass History
Figure 10. Sun-side View of WIRE Prior to the Installation of Silver-Teflon Outer Blanket Layer
Figure 11. Plot of solar array current vs. sun angle at 31 V, on day 159.
Figure 12. Power History
List of Tables
Table 1. Flight Heater Power Predictions
Table 2. Simulated On-Orbit Conditions
Table 3. Flight Model Correlation
Table 4. Flight Power Dissipations for Orbit Day 82 (In Watts)
Table 5. Measured Mass Distribution in Launch Configuration
Table 6. WIRE Inertia Matrix, On-Orbit Configuration with Tanks Empty (k-m2)
Table 7. Solar Array On-Orbit Performance
Table 8. Measured Power Consumption
Summary
The Wide-Field Infrared Explorer did not take a single infrared exposure. But WIRE's robust attitude control system enabled the team to recover the satellite after the tragic mishap. Subsequent operations successfully demonstrated the superior performance of nearly all of WIRE's subsystems. The mission clearly demonstrated the viability of a hydrogen cryostat on a Pegasus vehicle. Now, in addition to advancing space flight technology, WIRE is advancing science through novel use of its star tracker. The positive results from WIRE will have a lasting impact on space science.
Home
Last Revised: January 09, 2002
Digital Engineering Institute
Web Grunt: Richard Katz