physics

STS-41-D

STS-41-D is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand STS-41-D rather than just read about it. In short: STS-41-D (formerly STS-14) was the 12th flight of NASA's Space Shuttle program, and the maiden flight of Space Shuttle Discovery. It was launched from Kennedy Space Center, Florida, on August 30, 1984, and landed at Edwards Air Force Base, California, on September 5, 1984.

Key takeaways

STS-41-D 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-41-D to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of STS-41-D from memory before moving on to harder problems.

Reference excerpt

STS-41-D (formerly STS-14) was the 12th flight of NASA's Space Shuttle program, and the maiden flight of Space Shuttle Discovery. It was launched from Kennedy Space Center, Florida, on August 30, 1984, and landed at Edwards Air Force Base, California, on September 5, 1984. Three commercial communications satellites were deployed into orbit during the six-day mission, and a number of scientific experiments were conducted, including a prototype extendable solar array that would eventually form the basis of the main solar arrays on the International Space Station (ISS). The mission was delayed by more than two months from its original planned launch date, having experienced the Space Shuttle program's first launch abort at T−4 seconds on June 26, 1984.

Crew

Crew seat assignments

Mission background The launch was originally planned for June 25, 1984, but because of a variety of technical problems, including rollback to the Vehicle Assembly Building (VAB) to replace a faulty Space Shuttle Main Engine (SSME), the launch was delayed by over two months. The June 26, 1984, launch attempt marked the first time since Gemini 6A that a crewed spacecraft had experienced a shutdown of its engines just prior to launch.

June 1984 launch attempt During the June 26, 1984, launch attempt, there was a launch abort at T−4 seconds, followed by a pad fire about ten minutes later. Because the center engine had not started when the abort was triggered, confusion ensued as the flight controllers were unable to verify its state:

Commentary: "We have a cut off". "NTD [NASA Test Director] we have a RSLS [Redundant Set Launch Sequencer] abort". Commentary: "We have an abort by the onboard computers of the orbiter Discovery". "Break break, break break, GLS [Ground Launch Sequencer] shows engine one not shut down". "OK, PLT [pilot]?" "CSME [Space Shuttle Main Engines] verify engine one". "You want me to shut down engine one?" "We do not show engine start on one". "OTC [Orbiter test conductor] I can verify shutdown on verify on engine one, we haven't start prepped engine one". "All engines shut down I can verify that". Commentary: "We can now verify all three engines have been shut down". "We have red lights on engines two and three in the cockpit, not on one". "All right, CSME verify engine one safe for APU [auxiliary power unit] shutdown". "If I can verify that?" "OTC GPC [General Purpose Computer] go for APU shutdown".

Mission Specialist Steve Hawley was reported as saying following the abort: "Gee, I thought we'd be a lot higher at MECO (Main Engine Cut-Off)!". About ten minutes later, the following was heard on live TV coverage:

"We have indication two of our fire detectors on the zero level; no response. They're side by side right next to the engine area. The engineer requested that we turn on the heat shield fire water which is what could be seen spraying up in the vicinity of the engine bells of Discovery's three main engines".

While evacuating the shuttle 20 minutes later, the crew was doused with water from the pad deluge system, which was activated due to a hydrogen fire on the launch pad caused by the free hydrogen (fuel) that had collected around the engine nozzles following the shutdown and engine anomaly. Because the fire was invisible to humans, had the astronauts used the normal emergency escape procedure across the service arm to the slidewire escape baskets, they would have run into the fire. Changes to procedures resulting from the abort included more practicing of "safing" the orbiter following aborts at various points, the use of the fire suppression system in all pad aborts, and the testing of the slidewire escape system with a real person (Charles F. Bolden Jr.). It emerged that launch controllers were reluctant to order the crew to evacuate during the STS-41-D abort, as the slidewire had not been ridden by a human. Examination of telemetry data indicated that the engine malfunction had been caused by a stuck valve that prevented proper flow of LOX into the combustion chamber.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with STS-41-D

Start with the simplest possible case. Write down what STS-41-D 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-41-D 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-41-D 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-41-D

In research: STS-41-D 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-41-D 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-41-D is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1984 in science, 1984 in spaceflight, 1984 in the United States, so understanding it makes those chapters shorter.
In everyday life: Look for STS-41-D 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.

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How to study STS-41-D in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what STS-41-D 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-41-D out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is STS-41-D in simple terms?

Why does STS-41-D 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-41-D?

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-41-D.