STS-31

Key takeaways

STS-31 belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect STS-31 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of STS-31 from memory before moving on to harder problems.

Reference excerpt

STS-31 was the 35th mission of NASA's Space Shuttle program and the tenth flight of the Space Shuttle Discovery. The primary purpose of this mission was the deployment of the Hubble Space Telescope (HST) into low Earth orbit. Discovery lifted off from Launch Complex 39B on April 24, 1990, from Kennedy Space Center, Florida. Following the Challenger accident clarification was required on mission numbering. As STS-51-L was also designated STS-33, future flights with the previous STS-26 through STS-33 designators would require the R in their documentation to avoid conflicts in tracking data from one mission to another. Discovery's crew deployed the Hubble Space Telescope on April 25, 1990, and then spent the rest of the mission tending to various scientific experiments in the Shuttle's payload bay as well as operating a set of IMAX cameras to record the mission. Discovery's launch marked the first time since January 1986 that two Space Shuttles had been on the launch pad at the same time – Discovery on 39B and Columbia on 39A.

Crew

Crew seat assignments

Crew notes This mission was originally to be flown in August 1986 as STS-61-J using Atlantis, but was postponed due to the Challenger disaster. John W. Young was originally assigned to command this mission, which would have been his seventh spaceflight, but was reassigned to an administrative position and was replaced by Loren J. Shriver in 1988.

Mission highlights

STS-31 was launched on April 24, 1990, at 12:33:51 UTC (8:33:51 am EDT, local time at the launch site). A launch attempt on April 10, 1990, was scrubbed at T−4 minutes for a faulty valve in auxiliary power unit (APU) number one. The APU was eventually replaced, and the Hubble Space Telescope's batteries were recharged. On launch day, the countdown was briefly halted at T−31 seconds when Discovery's computers failed to shut down a fuel valve line on ground support equipment. Engineers manually commanded the valve to close and the countdown continued. The main purpose of this mission was to deploy Hubble. It was designed to operate above the Earth's turbulent and obscuring atmosphere to observe celestial objects at ultraviolet, visible and near-infrared wavelengths. The Hubble mission was a joint NASA-ESA (European Space Agency) effort going back to the late 1970s. The rest of the mission was devoted to photography and onboard experiments. To launch HST into an orbit that guaranteed longevity, Discovery entered an orbit of around 613 × 615 km (381 × 382 mi). At one point during the mission, Discovery briefly reached an apogee of 621 km (386 mi), the highest altitude ever reached by a Shuttle orbiter. The record height also permitted the crew to photograph Earth's large-scale geographic features not apparent from lower orbits. Motion pictures were recorded by two IMAX cameras, and the results appeared in the 1994 IMAX film Destiny in Space. Experiments on the mission included a biomedical technology study, advanced materials research, particle contamination and ionizing radiation measurements, and a student science project studying zero-gravity effects on electronic arcs. Discovery's reentry from its higher-than-usual orbit required a deorbit burn of 4 minutes and 58 seconds, the longest in Shuttle history up to that time. Discovery orbited the Earth 80 times during the mission. During the deployment of Hubble, one of the observatory's solar arrays stopped as it unfurled. While ground controllers searched for a way to command HST to unreel the solar array, Mission Specialists McCandless and Sullivan began preparing for a contingency spacewalk in the event that the array could not be deployed through ground control. The array eventually came free and unfurled through ground control while McCandless and Sullivan were pre-breathing inside the partially depressurized airlock. Secondary payloads included the IMAX Cargo Bay Camera (ICBC) to document operations outside the crew cabin and a handheld IMAX camera for use inside the orbiter. Also included were the Ascent Particle Monitor (APM) to detect particulate matter in the payload bay; a Protein Crystal Growth (PCG) experiment to provide data on growing protein crystals in microgravity, Radiation Monitoring Equipment III (RME III) to measure gamma ray levels in the crew cabin; Investigations into Polymer Membrane Processing (IPMP) to determine porosity control in the microgravity environment, and an Air Force Maui Optical Site (AMOS) experiment. The mission marked the flight of an 5 kg (11 lb) human skull, which served as the primary element of "Detailed Secondary Objective 469", also known as the In-flight Radiation Dose Distribution (IDRD) experiment. This joint NASA/DoD experiment was designed to examine the penetration of radiation into the human cranium during spaceflight. The female skull was seated in a plastic matrix, representative of tissue, and sliced into ten layers. Hundreds of thermo-luminescent dosimeters were mounted in the skull's layers to record radiation levels at multiple depths. This experiment, which also flew on STS-28 and STS-36, was located in the shuttle's mid-deck lockers on all three flights, recording radiation levels at different orbital inclinations. Discovery landed on Runway 22 at Edwards Air Force Base in California on April 29, 1990, at 13:49:57 UTC (6:49:57 am PDT, local time at the landing site). The landing had a rollout distance of 2,705 m (8,875 ft), took 61 seconds, and marked the first use of carbon brakes on a shuttle. Discovery was returned to Kennedy Space Center after STS-31 on May 7, 1990.

Wake-up calls NASA began a tradition of playing music to astronauts during the Project Gemini, which was first used to wake up a flight crew during Apollo 15. Each track is specially chosen, often by their families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.

Gallery

Illustrations

Worked examples

Example 1 — a first encounter with STS-31

Start with the simplest possible case. Write down what STS-31 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, 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-31 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-31 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-31

In research: STS-31 appears in physics 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-31 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-31 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Edwards Air Force Base, Hubble Space Telescope, Space Shuttle missions, so understanding it makes those chapters shorter.
In everyday life: Look for STS-31 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-31 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what STS-31 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-31 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is STS-31 in simple terms?

STS-31 was the 35th mission of NASA's Space Shuttle program and the tenth flight of the Space Shuttle Discovery. The primary purpose of this mission was the deployment of the Hubble Space Telescope (HST) into low Earth orbit.

Why does STS-31 matter?

Because it connects several physics 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-31?

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-31.