#sts-75

STS-75 - Columbia clears the tower at launch, 22 February 1996.

Crew portrait. Left to right, seated: Pilot Scott Horowitz; Commander Andrew Allen; Mission Specialist Franklin Chang-Diaz. Standing: Mission Specialist Maurizio Cheli (ESA); Mission Specialist Umberto Guidoni (ESA); Mission Specialist Jeffrey Hoffman; Mission Specialist Claude Nicollier (ESA).

STS-75's primary mission was the deployment of the Tethered Satellite System (TSS-1R), a joint NASA and Italian Space Agency venture meant to verify gravity gradient stabilization (a passive method of satellite attitude control) and to provide a research facility for the investigation of space physics and plasma electrodynamics. This was a reflight of the system, after the first test on the Space Shuttle Atlantis in 1992, known as TSS-1, resulted in the tether getting stuck during deployment and the mission objectives were not achieved.

Deployment of TSS-1R.

Ultimately, the tether broke during deployment as a result of electrical discharge through a damaged section of insulation. However, several scientific hypotheses were confirmed during TSS-1R operations, so the mission was not a total loss.

Columbia would return to Earth on 9 March 1996 at the Shuttle Landing Facility in Florida.

"Onboard Space Shuttle Columbia (STS-75) the vertical stabilizer appears to point to the four stars of the Southern Cross. The scene was captured with a 35mm camera just prior to a sunrise."

Date: February 22, 1996

"Microgravity

Onboard photo of Space Shuttle Columbia's (STS-75) open cargo bay carrying the United States Microgravity Payload-3 (USMP-3) at night."

Date: February 22, 1996

"CAPE CANAVERAL, Fla. -- This orbiter tribute of space shuttle Columbia, or OV-102, hangs in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. The tribute features Columbia, the “first of the fleet," rising above Earth at the dawn of the Space Shuttle Program. Columbia's accomplishments include the launch and deployment of NASA's Chandra X-ray Observatory on STS-93, the first shuttle landing at White Sands Space Harbor in New Mexico on STS-3, the first deployment of commercial satellites and the first four-member crew during STS-5, the first Spacelab mission and first six-member crew on STS-9, the first female commander, Eileen Collins, on STS-93, as well as several laboratory missions with international partners. Crew-designed patches for each of Columbia’s missions lead from Earth toward a remembrance of the STS-107 crew, which was lost during re-entry on Feb. 1, 2003. Five orbiter tributes are on display in the firing room, representing Atlantis, Challenger, Columbia, Endeavour and Discovery."

Date: July 29, 2010

Footage from STS-75 and STS-80, 1996

Source: NASA/JSC

The TSS-1R as seen from Columbia during STS-75 in 1996.

The TSS-1R, or Tethered Satellite System, was a NASA/Italian Space Agency joint mission to investigate tethered satellite systems.

TSS-1R was originally flown on board Atlantis during STS-46 as TSS-1 in 1992, where it was deployed out to a length of around 256m before a protruding bolt prevented the tether to be deployed any further. It was then chosen to refly on STS-75 after the bolt had been taken care of, to continue its investigation of electrical generation from tethered systems 123.

NASA TSS-1 seen being prepped on the ground before STS-46

The tether was a 20.7km long strand of a 2.54mm thin combination of Nomex, Kevlar, Teflon and copper wire and was electrically connected to the 1.6m spherical satellite and the space shuttle. Inside of the satellite were 6 scientific experiments, their supporting hardware and batteries and some cold-gas Nitrogen thrusters to assist in the deployment and control of the satellite.

NASA TSS-1 being deployed during STS-46.

During the deployment the tether snapped after around 19.7km had been deployed, causing the satellite to fly off into a higher orbit, where it remained for several weeks before reentering the atmosphere4.

The effect of the tether/satellite passing through earth's magnetic field would cause it to generate electricity through the principle of electromagnetic induction5. Although the tether was broken, the batteries onboard the satellite allowed it to continue transmitting scientific data for about 3 days after that, and during the time the tether was extended, reports showed that the root-square of the voltage generated could be as high as 1200 volts 6.

The neat thing about space tethers is that not only can they be used for electrical generation, they can also be used to keep a satellite or other orbital outpost in orbit, by applying current to the tether, causing it to act like a motor and push the satellite away from the Earths magnetic field. They can also be used to help stabilize systems or be used to do a controlled release of small payloads into earths atmosphere without the need to complete a deorbit burn7.

NASA TSS-1R Seen during deployment on STS-75

http://science.nasa.gov/missions/tss/ ↩︎

http://en.wikipedia.org/wiki/STS-46 ↩︎

http://en.wikipedia.org/wiki/STS-75 ↩︎

http://spinoff.nasa.gov/spinoff1996/6.html ↩︎

http://en.wikipedia.org/wiki/Electrodynamic_tether#Tethers_as_generators ↩︎

http://onlinelibrary.wiley.com/doi/10.1029/97GL02958/abstract ↩︎