This paper documents a series of estimates of the orbital lifetime of the SEDS-2 flight configuration made prior to the mission. These estimates were made with program LTIME, which has been in use at MSFC for a number of years. Because of the unusual configuration of upper-stage/tether/endmass flown on this mission, and the type of assumptions and inputs used in LTIME, the effective area used in the drag calculation had to be estimated in an unusual way. The final pre-flight predicted lifetime was 28.35 days. In the actual flight, the tether was cut approximately 5 days into the mission. The instrumented endmass plus about 12 km of tether rapidly reentered the atmosphere, and the Delta II Second Stage plus the remaining 8 km of tether reentered on mission day 60. Tracking data was used to reconstruct reentry sequences for the two parts of the configuration after the cut. The predicted lifetimes for the endmass plus tether-fragment were in the range of 0.2 to 2.8 days, depending on the perigee altitudes assumed. The predicted lifetime of the upper-stage plus tether was 56.4 days, which corresponds to reentry on mission day 61, in good agreement with the actual reentry on day 60.
Comparison of Predicted and Actual Orbital Lifetimes for the SEDS-2 Mission
1994
10 pages
Report
Keine Angabe
Englisch
Astronautics , Spacecraft Trajectories & Flight Mechanics , Data correlation , Data processing , Drag measurement , Estimates , Orbital lifetime , Performance prediction , Spaceborne experiments , Tethered satellites , Altitude , Applications programs (Computers) , Nasa space programs , Perigees , Sequencing , Tethering
Post Deployment Recontact Issues for the SEDS/SEDSAT Mission
British Library Conference Proceedings | 1996
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