science

STS-51-D

STS-51-D is a science 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-51-D rather than just read about it. In short: STS-51-D was the 16th flight of NASA's Space Shuttle program, and the fourth flight of Space Shuttle Discovery. The launch of STS-51-D from Kennedy Space Center (KSC), Florida, on April 12, 1985, was delayed by 55 minutes, after a boat strayed into the restricted Solid Rocket Booster (SRB) recovery zone.

Key takeaways

STS-51-D 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-51-D to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of STS-51-D from memory before moving on to harder problems.

Reference excerpt

STS-51-D was the 16th flight of NASA's Space Shuttle program, and the fourth flight of Space Shuttle Discovery. The launch of STS-51-D from Kennedy Space Center (KSC), Florida, on April 12, 1985, was delayed by 55 minutes, after a boat strayed into the restricted Solid Rocket Booster (SRB) recovery zone. STS-51-D was the third shuttle mission to be extended. On April 19, 1985, after a week-long flight, Discovery conducted the fifth shuttle landing at KSC. The shuttle suffered extensive brake damage and a ruptured tire during landing. This forced shuttle landings to be done at Edwards Air Force Base, California for the next five years until the development and implementation of nose wheel steering made landings at KSC more feasible.

Crew

Spacewalk Personnel: Hoffman and Griggs Date: April 16, 1985 (≈12:30–15:30 UTC) Duration: 3 hours, 6 minutes

Crew seat assignments

Mission summary During STS-51-D, the shuttle crew deployed two communications satellites: Telesat-I (Anik C1) and Syncom IV-3 (also known as Leasat-3); both were Hughes-built satellites. Telesat-I was attached to a Payload Assist Module (PAM-D) motor and successfully deployed. Syncom IV-3, however, failed to initiate antenna deployment and spin-up, or ignite its perigee kick motor upon deployment. The mission was consequently extended by two days to ensure that the satellite's spacecraft sequencer start lever was in its proper position. Griggs and Hoffman performed an unscheduled Extravehicular Activity (EVA) to attach homemade "Flyswatter" devices to the shuttle's Remote Manipulator System (Canadarm). Seddon then engaged the satellite's start lever using the RMS, but again the post-deployment sequence did not begin. The satellite was subsequently retrieved, repaired and successfully redeployed during the STS-51-I mission later that year. Discovery's other mission payloads included the Continuous Flow Electrophoresis System III (CFES-III), which was flying for the sixth time; two Shuttle Student Involvement Program (SSIP) experiments; the American Flight Echo-cardiograph (AFE); two Getaway specials (GASs); a set of Phase Partitioning Experiments (PPE); an astronomical photography verification test; various medical experiments; and "Toys in Space", an informal study of the behavior of simple toys in a microgravity environment, with the results being made available to school students upon the shuttle's return. Discovery landed on Runway 33 of the Shuttle Landing Facility at Kennedy Space Center at 13:54:28 UTC (8:54:28 am EST local time at the landing site). As the orbiter approached the runway, it was buffeted by a 10-mile-per-hour (16 km/h; 8.7 kn) crosswind from the right, which pushed the orbiter 19 feet (5.8 m) left of the runway's center line as the rear landing gear touched down. As the orbiter rolled out, the crosswind continued to push it towards the left, causing it to drift 65 feet (20 m) from the center line of the 300-foot-wide (91 m) runway. At this point, Commander Bobko began to counteract the drift by applying more pressure to the right-wheel brakes, a technique called differential steering, which brought the orbiter back to the center of the runway. However, he had to apply twice as much force to the right brakes and about 134 feet (41 m) before stopping the brakes on the right-side inboard tire locked up and 5 feet (1.5 m) before stopping the brakes on the right-side outboard tire locked up and the inboard tire blew. The incident prompted NASA to add nose wheel steering to the orbiters, which was complete by late 1985. Until that work was completed, NASA would land the orbiters at the Edwards Air Force Base which offered the option of landing on a long and wide dry lake bed from more directions. Nose wheel steering was also implemented shortly before the Challenger disaster, which would ground the shuttle program for a time. Ultimately, it would be five years until a mission would again land at the SLF, when STS-38 had to divert there due to bad weather at Edwards.

Wake-up calls NASA began a tradition of playing music to astronauts during the Project Gemini, and first used music to wake up a flight crew during Apollo 15. Each track is specially chosen, often by the astronauts' 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-51-D

Start with the simplest possible case. Write down what STS-51-D 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-51-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-51-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-51-D

In research: STS-51-D 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-51-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-51-D is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1985 in spaceflight, 1985 in the United States, Space Shuttle missions, so understanding it makes those chapters shorter.
In everyday life: Look for STS-51-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-51-D in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what STS-51-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-51-D out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is STS-51-D in simple terms?

Why does STS-51-D 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-51-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-51-D.