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Tracy's Rock

Tracy's Rock is a biology 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 Tracy's Rock rather than just read about it. In short: Tracy's Rock, known as Split Rock or the Station 6 Boulder in the scientific literature, is a large boulder on the Moon which was visited by the Apollo 17 crew on December 13, 1972, at their Taurus-Littrow landing site. "Tracy's Rock" is its popular name. Geologically it is impact melt breccia, having broken off from the North Massif.

Tracy's Rock — main illustration
Tracy's Rock — illustration

Key takeaways

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

Reference excerpt

Tracy's Rock, known as Split Rock or the Station 6 Boulder in the scientific literature, is a large boulder on the Moon which was visited by the Apollo 17 crew on December 13, 1972, at their Taurus-Littrow landing site. "Tracy's Rock" is its popular name. Geologically it is impact melt breccia, having broken off from the North Massif.

Examination Geologist-astronaut Harrison Schmitt and mission commander Gene Cernan spent considerable time studying the rock and its vicinity at station 6 during their third Extravehicular Activity (EVA-3).

"Gene stepped to the northeast corner of fragment 1, put his left hand on the dust-covered shelf to support himself, and reached out as far as possible toward the center of the dusted area and swept the bag twice from his right to his left, leaving furrows and, at the lefthand end of each furrow, a small mound of dust where he stopped... A labeled detail from frame AS17-140-21496 shows the sample location, the area on the shelf probably disturbed by his left hand, and the area on the ground between fragment 1 and the foreground rock that he disturbed while taking the sample and earlier, at about 165:25:48, in the flightline." At about 165:33:38, Cernan took a series of photos from higher up the hill. In this photomontage, Schmitt is standing to the left of the rock and the Lunar Roving Vehicle (LRV) is parked to the right.

"Cernan - 'I haven't seen the rock from this perspective in nearly nineteen years. My hand print really shows you how big the rock is and, in 21482, you can see across to the South Massif and the Scarp. The Scarp looks small in this photo, but I remember how big it was (80 meters) because we went up it.'" The Tracy's Rock/Station 6 panorama is also featured in David Harland's "Geology 101 Field Trip" on the Apollo Lunar Surface Journal's "Fun Images" page.

Naming The patch of dirt on the north face of the boulder is the subject of a 1984 painting by Apollo 12 astronaut Alan Bean. Bean took up a career as a professional artist after he left the Astronaut Corps and developed a considerable reputation as a space artist. As a result of the painting, those who know the story call the Station 6 boulder "Tracy's Rock". Tracy is Gene Cernan's daughter, who was nine years old at the time of the mission.

"Cernan - 'It was on this part of the rock that Al Bean wrote "Tracy", my daughter's name, in one of his paintings. After we came home I started to see a picture of the boulder in lots of places. It was the picture of Jack going past the corner of the rock (21496), one of the pictures from my pan. It became very popular. One day Al Bean came by and said he was doing a painting of it. And it was a big painting, six feet by three feet or something like that. "Al likes to have stories in his paintings and he wanted to talk about it. So we talked about the slope and how hard it was to climb up there and I said that, if I'd known the picture was going to get so much notoriety, I wished I would have done something that I hadn't even thought of at the time. And that is to have printed Tracy's name in the dust. "Al's daughter Amy and Tracy had grown up together and he asked 'How would you have done it'. So I wrote it out on a piece of paper and, some time later, he called and wanted me to come over and look at what he'd done. He had erased the place where I'd taken the sample and had put in Tracy's name, instead. "And in the little story he put with the picture, he said that he'd done it to save me the trouble of going back to do it myself, and to save the taxpayers the expense of sending me back."

See also List of individual rocks

References

Alan Bean Gallery - Tracy's Boulder Archived 2006-04-30 at the Wayback Machine, 1984 NASA Human Spaceflight Gallery

Illustrations

Tracy's Rock: Astronaut Harrison Schmitt working next to Tracy's Rock in the Taurus–Littrow valley on the Apollo 17 mission in 1972. The South massif is visible to the right.
Astronaut Harrison Schmitt working next to Tracy's Rock in the Taurus–Littrow valley on the Apollo 17 mission in 1972. The South massif is visible to the right.

Worked examples

Example 1 — a first encounter with Tracy's Rock

Start with the simplest possible case. Write down what Tracy's Rock claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Tracy's Rock 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 Tracy's Rock 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 Tracy's Rock

In research
Tracy's Rock appears in biology 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 Tracy's Rock 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
Tracy's Rock is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alan Bean, Apollo 17, Gene Cernan, so understanding it makes those chapters shorter.
In everyday life
Look for Tracy's Rock 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 Tracy's Rock in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Tracy's Rock means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Tracy's Rock out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tracy's Rock in simple terms?

Tracy's Rock, known as Split Rock or the Station 6 Boulder in the scientific literature, is a large boulder on the Moon which was visited by the Apollo 17 crew on December 13, 1972, at their Taurus-Littrow landing site. "Tracy's Rock" is its popular name. Geologically it is impact melt breccia, hav…

Why does Tracy's Rock matter?

Because it connects several biology 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 Tracy's Rock?

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 Tracy's Rock.

Tags

  • Alan Bean
  • Apollo 17
  • Gene Cernan
  • Harrison Schmitt
  • Surface features of the Moon

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