TiPS

Tether Physics and Survivability Experiment

TiPS was a short-fuse experiment, with only 6 months between initial discussions and TAI delivery of tether and deployer to the Naval Research Lab. Instead of deploying tether from an actively-stabilized host vehicle as SEDS and PMG did, TiPS involved a small spin-stabilized assembly that separated into two endmasses. The endmasses were ejected apart energetically enough to deploy 4 km of 2mm diameter SEDS tether between them. The tether used Spectra fiber for impact tolerance, braided around an acrylic sweater-yarn core to expand the tether diameter after deployment. The diameter increase also decreased the average tether density. Both factors may have contributed to an improved robustness against debris and micrometeoroid impact, compared to the all-Spectra SEDS-2 tether.

Deployment rates were monitored by on-board optical turn-count detectors, as on SEDS-1 and -2. Part of deployment was also imaged by ground-based telescope. Thereafter, occasional laser ranging allowed measurement of libration. This decayed substantially on a timescale of months.

TiPS started out in a 1020 km 63 degree inclination circular orbit in June 1996. Orbit perturbations cause a steady eccentricity increase of 0.0033/year. This should cause reentry ~25 years after launch, by dropping the perigee low enough for aerodynamic drag to become significant.