science

Primary Atomic Reference Clock in Space

Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space rather than just read about it. In short: The Primary Atomic Reference Clock in Space or PARCS was an atomic-clock mission scheduled to fly on the International Space Station (ISS) in 2008, but cancelled to make way for the Vision for Space Exploration. The mission, to have been funded by NASA, involved a laser-cooled caesium atomic clock, and a time-transfer system using Global Positioning System (GPS) satellites.

Key takeaways

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

Reference excerpt

The Primary Atomic Reference Clock in Space or PARCS was an atomic-clock mission scheduled to fly on the International Space Station (ISS) in 2008, but cancelled to make way for the Vision for Space Exploration. The mission, to have been funded by NASA, involved a laser-cooled caesium atomic clock, and a time-transfer system using Global Positioning System (GPS) satellites. PARCS was to fly concurrently with the Superconducting Microwave Oscillator (SUMO) a different type of clock that was to be compared against the PARCS clock to test certain theories. The objectives of the mission were to have been:

Test gravitational theory Study laser-cooled atoms in microgravity Improve the accuracy of timekeeping on earth

Experiment location The proposed ISS location for the experiment was on the External Facility of the Japanese Experimental Module (JEM). This location afforded good views of the GPS constellation of satellites, needed for comparing space and ground clocks. In addition, the volume, available power, and coolant system were well matched to the mission requirements.

Goals The microgravity environment of space allows slowing of atoms to speeds well below those used in terrestrial atomic clocks, providing for substantial improvement in clock accuracy. This very accurate space clock will be compared continuously to the SUMO oscillator, and these two clocks (being fundamentally different) will provide a test of "local position invariance." Comparisons between the space and earth clocks will yield a related, but important measurement of the gravitational frequency shift. Finally, the signals conveyed to the ground through the GPS time-transfer system will serve as a truly international time standard available to anyone on earth.

Institutions and people PARCS is a cooperative effort between the following organizations:

Jet Propulsion Laboratory (JPL), which contributed Flight Hardware Development National Institute of Standards and Technology (NIST), which contributed Concept/Development Testing University of Colorado, which contributed Gravitational Testing

Staff Bill Klipstein of JPL was the Project Scientist, and Dave Seidel of JPL was the Project Manager. The Co-Principal Investigators were Don Sullivan and Bill Phillips of NIST, and Neil Ashby of the University of Colorado. John Lipa of Stanford University was the Principal Investigator for SUMO and John Dick of JPL was the Project Scientist for that program.

References

External links National Institute of Standards and Technology

Worked examples

Example 1 — a first encounter with Primary Atomic Reference Clock in Space

Start with the simplest possible case. Write down what Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space

In research: Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space 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: Primary Atomic Reference Clock in Space is common in secondary-school and first-year university syllabi. It links to neighbouring topics Atomic clocks, so understanding it makes those chapters shorter.
In everyday life: Look for Primary Atomic Reference Clock in Space 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Primary Atomic Reference Clock in Space” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Primary Atomic Reference Clock in Space in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Primary Atomic Reference Clock in Space in simple terms?

Why does Primary Atomic Reference Clock in Space 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 Primary Atomic Reference Clock in Space?

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 Primary Atomic Reference Clock in Space.