STS-75

Key takeaways

STS-75 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect STS-75 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of STS-75 from memory before moving on to harder problems.

Reference excerpt

STS-75 was a 1996 NASA Space Shuttle mission, the 19th mission of the Columbia orbiter.

Crew

Crew seat assignments

Mission objective

Tethered Satellite System The primary objective of STS-75 was to carry the Tethered Satellite System Reflight (TSS-1R) into orbit and to deploy it spaceward on a conducting tether. The mission also flew the United States Microgravity Payload (USMP-3) designed to investigate materials science and condensed matter physics. The TSS-1R mission was a reflight of TSS-1 which was flown onboard Space Shuttle Atlantis on STS-46 in July/August 1992. The Tether Satellite System circled the Earth at an altitude of 296 kilometers, placing the tether system within the rarefied electrically charged layer of the atmosphere known as the ionosphere. STS-75 mission scientists hoped to deploy the tether to a distance of 20.7 kilometers (12.9 mi; 11.2 nmi). Over 19 kilometers (12 mi; 10 nmi) of the tether was deployed (over a period of 5 hours) before the tether broke. Many pieces of floating debris were produced by the plasma discharge and rupture of the tether, and some collided with it. The satellite remained in orbit for a number of weeks and was easily visible from the ground.

The electric conductor of the tether was a copper braid wound around a nylon (Nomex) string. It was encased in teflon-like insulation, with an outer cover of kevlar, inside a nylon (Nomex) sheath. The culprit turned out to be the innermost core, made of a porous material which, during its manufacture, trapped many bubbles of air at atmospheric pressure. Later vacuum-chamber experiments suggested that the unwinding of the reel uncovered pinholes in the insulation. That in itself would not have caused a major problem, because the ionosphere around the tether, under normal circumstance, was too rarefied to divert much of the current. However, the air trapped in the insulation changed that. As air bubbled out of the pinholes, the high voltage of the nearby tether, about 3500 volts, converted it into a relatively dense plasma (similar to the ignition of a fluorescent tube), and therefore made the tether a much better conductor of electricity. This plasma diverted to the metal of the shuttle and from there to the ionospheric return circuit. That current was enough to melt the cable. The specific TSS-1R mission objectives were: characterize the current-voltage response of the TSS-orbiter system, characterize the satellite's high-voltage sheath structure and current collection process, demonstrate electric power generation, verify tether control laws and basic tether dynamics, demonstrate the effect of neutral gas on the plasma sheath and current collection, characterize the TSS radio frequency and plasma wave emissions and characterize the TSS dynamic-electrodynamic coupling. TSS-1R Science Investigations included: TSS Deployer Core Equipment and Satellite Core Equipment (DCORE/SCORE), Research on Orbital Plasma Electrodynamics (ROPE), Research on Electrodynamic Tether Effects (RETE), Magnetic Field Experiment for TSS Missions (TEMAG), Shuttle Electrodynamic Tether System (SETS), Shuttle Potential and Return Electron Experiment (SPREE), Tether Optical Phenomena Experiment (TOP), Investigation of Electromagnetic Emissions by the Electrodynamic Tether (EMET), Observations at the Earth's Surface of Electromagnetic Emissions by TSS (OESSE), Investigation and Measurement of Dynamic Noise in the TSS (IMDN), Theoretical and Experimental Investigation of TSS Dynamics (TEID) and the Theory and Modeling in Support of Tethered Satellite Applications (TMST).

Other mission objectives The USMP-3 payload consisted of four major experiments mounted on two Mission Peculiar Experiment Support Structures (MPESS) and three Shuttle Mid-deck experiments. The experiments were: Advanced Automated Directional Solidification Furnace (AADSF), Material pour l'Etude des Phenomenes Interessant la Solidification sur Terre et en Orbite (MEPHISTO), Space Acceleration Measurement System (SAMS), Orbital Acceleration Research Experiment (OARE), Critical Fluid Light Scattering Experiment (ZENO) and Isothermal Dendritic Growth Experiment (IDGE).

Alternating use of bunk bed Jewish astronauts Jeffrey A. Hoffman and Scott J. Horowitz alternated use of the same bunk bed. Upon Horowitz's request, Hoffman attached a mezuzah using Velcro.

Fictional STS-75 mission STS-75 was the shuttle mission described in the fictional NASA Document 12-571-3570, although this document was disseminated several years before STS-75 was launched. The document purports to report on experiments to determine effective sexual positions in microgravity. Astronomer and scientific writer Pierre Kohler mistook this document for fact and is responsible for a major increase in its redistribution in the early 21st century. Conspiracy theories first made in the early beginnings of the Shuttle era of sex in space were suddenly made rampant again, causing a minor press debacle among tabloids.

References

This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

Stern, David P.; Peredo, Mauricio. "The Exploration of the Earth's Magnetosphere: The Space Tether Experiment". NASA.

External links

Media related to STS-75 at Wikimedia Commons NASA mission summary Archived 2 June 2007 at the Wayback Machine STS-75 Video Highlights Archived 10 November 2013 at the Wayback Machine Evans, Ben (23 February 2014). "'The Tether Is Broken': The Second Flight of the Tethered Satellite (Part 2)". AmericaSpace. Archived from the original on 22 September 2015.

Illustrations

Worked examples

Example 1 — a first encounter with STS-75

Start with the simplest possible case. Write down what STS-75 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to STS-75 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about STS-75 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of STS-75

In research: STS-75 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses STS-75 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: STS-75 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Space Shuttle missions, Spacecraft launched in 1996, so understanding it makes those chapters shorter.
In everyday life: Look for STS-75 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study STS-75 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what STS-75 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain STS-75 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is STS-75 in simple terms?

STS-75 was a 1996 NASA Space Shuttle mission, the 19th mission of the Columbia orbiter. Crew Crew seat assignments Mission objective Tethered Satellite System The primary objective of STS-75 was to carry the Tethered Satellite System Reflight (TSS-1R) into orbit and to deploy it spaceward on a cond…

Why does STS-75 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study STS-75?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on STS-75.