SEDS (Small Expendable-tether Deployer System)
Two SEDS missions have been flown to date. Each involved the deployment of a 20-km tether at the downward end of which was the de-orbit. The principle is that the tether acts as a thruster causing the lower satellite to hover at an altitude below that which the orbital angular rate would allow, thus causing the orbit to decay. SEDS-1 and SEDS-2 were both successful, although the SEDS-2 tether was severed after five days by a micrometeroid or piece of space debris.
NASA has successfully deployed three SEDS Class (Small Expendable Deployer System) probes: SEDS-1 and -2 were 20 km missions and PMG (Plasma Motor Generator) was a 500 m mission. All tethered systems were attached to a spent Delta second stage. Not only were tether models verified, it was demonstrated that a probe can be downwardly deployed from a very long tether.
See also TSS (Tethered Satellite System) and ProSEDS (Propulsive Small Expendable Deployer System.
Related category SATELLITES AND SPACE PROBES
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