astronomy

STS-61

STS-61 is a astronomy 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-61 rather than just read about it. In short: STS-61 was NASA's first Hubble Space Telescope servicing mission, and the fifth flight of the Space Shuttle Endeavour. The mission launched on December 2, 1993, from Kennedy Space Center (KSC) in Florida.

Key takeaways

STS-61 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect STS-61 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of STS-61 from memory before moving on to harder problems.

Reference excerpt

STS-61 was NASA's first Hubble Space Telescope servicing mission, and the fifth flight of the Space Shuttle Endeavour. The mission launched on December 2, 1993, from Kennedy Space Center (KSC) in Florida. The mission restored the spaceborne observatory's vision (marred by spherical aberration in its mirror) with the installation of a new main camera and a corrective optics package (COSTAR). This correction occurred more than three and a half years after the Hubble was launched aboard STS-31 in April 1990. The flight also brought instrument upgrades and new solar arrays to the telescope. With its very heavy workload, the STS-61 mission was one of the most complex in the Shuttle's history. STS-61 lasted almost 11 days, and crew members made five spacewalks (extravehicular activities (EVAs)), an all-time record; even the re-positioning of Intelsat VI on STS-49 in May 1992 required only four. The flight plan allowed for two additional EVAs, which could have raised the total number to seven; the final two contingency EVAs were not made. In order to complete the mission without too much fatigue, the five EVAs were shared between two pairs of different astronauts alternating their shifts. During the flight, mission specialist Jeffrey A. Hoffman also spun a dreidel for the holiday of Hanukkah to a live audience watching via satellite.

Crew

Backup crew

Spacewalks Musgrave and Hoffman – EVA 1 EVA 1 Start: December 5, 1993 – 03:44 UTC EVA 1 End: December 5, 1993 – 11:38 UTC Duration: 7 hours, 54 minutes Thornton and Akers – EVA 2 EVA 2 Start: December 6, 1993 – 03:29 UTC EVA 2 End: December 6, 1993 – 10:05 UTC Duration: 6 hours, 36 minutes Musgrave and Hoffman – EVA 3 EVA 3 Start: December 7, 1993 – 03:35 UTC EVA 3 End: December 7, 1993 – 10:22 UTC Duration: 6 hours, 47 minutes Thornton and Akers – EVA 4 EVA 4 Start: December 8, 1993 – 03:13 UTC EVA 4 End: December 8, 1993 – 10:03 UTC Duration: 6 hours, 50 minutes Musgrave and Hoffman – EVA 5 EVA 5 Start: December 9, 1993 – 03:30 UTC EVA 5 End: December 9, 1993 – 10:51 UTC Duration: 7 hours, 21 minutes

Crew seat assignments

Mission highlights

Launch

Endeavour was switched from Pad 39A to Pad 39B due to contamination of the Payload Changeout Room after a windstorm on October 30, 1993. The internal HST payload package was not affected because it was tightly sealed, and the contamination appeared to have been caused by sandblasting grit from recent Pad A modifications. On November 18, 1993, Endeavour experienced a failure of a transducer on the elevon hydraulic actuator. To replace the actuator would have required a rollback to the Orbiter Processing Facility (OPF) because access to the actuator was only through the Main Landing Gear wheel well. Since there were 4 delta-P transducers and the Launch commit criteria (LCC) required only 3 of 4, the transducer was depinned and would not be consulted during flight. The flight crew arrived at the KSC Shuttle Landing Facility (SLF) on November 27, 1993, and the payload bay doors were closed at 20:20 UTC on November 28, 1993. The first launch attempt on December 1, 1993, was scrubbed due to weather constraint violations at the Shuttle Landing Facility. Just before the scrub the range was also in a no-go situation due to an 240 m (790 ft) long ship in the restricted sea zone. A 24‑hour scrub turnaround was put into effect with a launch window extending from 09:26 to 10:38 UTC on December 2, 1993. Launch mass was 113,541 kg (250,315 lb). Payload mass was 8,011 kg (17,661 lb). After launch, the astronauts carried out a series of checks on the vehicle and went to sleep seven and a half hours after liftoff.

Flight Day 2 Endeavour performed a series of burns that allowed the shuttle to close in on the Hubble Space Telescope at a rate of 110 km (68 mi) per 95-minute orbit. The crew made a detailed inspection of the payload and checked out both the robot arm (Canadarm) and the spacesuits. All of Endeavour's systems functioned well as the crew got a full day's sleep in preparation for the evening's rendezvous. At the end of Flight Day 2, Endeavour was 350 km (220 mi) behind HST and closing.

Flight Day 3

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with STS-61

Start with the simplest possible case. Write down what STS-61 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, 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-61 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-61 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-61

In research: STS-61 appears in astronomy 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-61 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-61 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hubble Space Telescope servicing missions, Space Shuttle missions, Spacecraft launched in 1993, so understanding it makes those chapters shorter.
In everyday life: Look for STS-61 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-61 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what STS-61 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-61 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is STS-61 in simple terms?

Why does STS-61 matter?

Because it connects several astronomy 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-61?

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-61.