science

Heat Capacity Mapping Mission

Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission rather than just read about it. In short: The Heat Capacity Mapping Mission (HCMM) spacecraft was the first of a series of Applications Explorer Mission (AEM) of the Explorer program. Mission The objective of the HCMM was to provide comprehensive, accurate, high-spatial-resolution thermal surveys of the surface of the Earth.

Key takeaways

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

Reference excerpt

The Heat Capacity Mapping Mission (HCMM) spacecraft was the first of a series of Applications Explorer Mission (AEM) of the Explorer program.

Mission The objective of the HCMM was to provide comprehensive, accurate, high-spatial-resolution thermal surveys of the surface of the Earth.

Spacecraft The HCMM spacecraft was made of two distinct modules: (1) an instrument module, containing the heat capacity mapping radiometer and its supporting gear, and (2) a base module, containing the data handling, power, communications, command, and attitude control subsystems required to support the instrument module. The spacecraft was spin stabilized at a rate of 14 rpm. The HCMM circular Sun-synchronous orbit allowed the spacecraft to sense surface temperatures near the maximum and minimum of the diurnal cycle. The orbit had a daylight ascending node with a nominal equatorial crossing time of 14:00 hours. Since there was no inclination adjustment capacity, the spacecraft drifted from this crossing time by about 1 hour earlier per year. There was no onboard data storage capability, so only real-time data were transmitted when the satellite came within the reception range of seven ground stations. The repeat cycle of the spacecraft was 16 days. Day/night coverage over a given area between the latitudes of 85°N and 85°S occurred at intervals ranging from 12 to 36 hours (once every 16 days).

Experiment

Heat Capacity Mapping Radiometer (HCMR) The objectives of the Heat Capacity Mapping Radiometer (HCMR) were (1) to produce thermal maps at the optimum times for making thermal-inertia studies for discrimination of rock types and mineral resources location, (2) to measure plant-canopy temperatures at frequent intervals to determine the transpiration of water and plant life, (3) to measure soil-moisture effects by observing the temperature cycle of soils, (4) to map thermal effluents, both natural and man-made, (5) to investigate the feasibility of geothermal source location by remote sensing, and (6) to provide frequent coverage of snow fields for water runoff prediction. The HCMR transmitted analog data in real-time to selected receiving stations. The radiometer was similar to the surface composition mapping radiometer (SCMR) of Nimbus 5 (1972-097A). The HCMR had a small instantaneous geometric field of view of 0.83 mrad, high radiometric accuracy, and a wide 716 km (445 mi) swath coverage on the ground so that selected areas were covered within the 12-hour period corresponding to the maximum and minimum of temperature observed. The instrument operated in two channels, 10.5 to 12.5 micrometers (IR) and 0.55 to 1.1 micrometers (visible). The spatial resolution was approximately 600 m (2,000 ft) at nadir for the Infrared (IR) channel, and 500 m (1,600 ft) for the visible channel. The instrument utilized a radiation cooler to cool the two Mercury cadmium telluride (|Hg-Cd-Te) detectors to 115 K. The experiment included an analog multiplexer that accepted the analog outputs of the detectors and multiplexed them in a form suitable for transmission by the spacecraft S-band transmitter. The instrument performed satisfactorily until the spacecraft operations terminated on 30 September 1980.

Launch HCMM was launched from Vandenberg Air Force Base on 26 April 1978 by a Scout D-1 launch vehicle. Its mass was 117 kg (258 lb).

End of mission and entry During 21-23 February 1980, the HCMM orbital altitude was lowered from 620 km (390 mi) to 540 km (340 mi) to stop the drift of the orbit plane to unfavorable Sun angles which in turn reduced the power collection capability of the solar panels. The operations of the spacecraft were terminated on 30 September 1980. HCMM re-entered in the Earth's atmosphere on 22 December 1981.

Illustrations

Worked examples

Example 1 — a first encounter with Heat Capacity Mapping Mission

Start with the simplest possible case. Write down what Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission

In research: Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission 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: Heat Capacity Mapping Mission is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1978 in spaceflight, Applications Explorer Mission, Explorers Program, so understanding it makes those chapters shorter.
In everyday life: Look for Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission in 20 minutes

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

Frequently asked questions

What is Heat Capacity Mapping Mission in simple terms?

The Heat Capacity Mapping Mission (HCMM) spacecraft was the first of a series of Applications Explorer Mission (AEM) of the Explorer program. Mission The objective of the HCMM was to provide comprehensive, accurate, high-spatial-resolution thermal surveys of the surface of the Earth.

Why does Heat Capacity Mapping Mission 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 Heat Capacity Mapping Mission?

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 Heat Capacity Mapping Mission.