astronomy

Picard (satellite)

Picard (satellite) 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 Picard (satellite) rather than just read about it. In short: PICARD is a satellite dedicated to the simultaneous measurement of the absolute total and spectral solar irradiance, the diameter and solar shape, and to the Sun's interior probing by the helioseismology method. These measurements obtained throughout the mission allow study of their variations as a function of solar activity.

Key takeaways

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

Reference excerpt

PICARD is a satellite dedicated to the simultaneous measurement of the absolute total and spectral solar irradiance, the diameter and solar shape, and to the Sun's interior probing by the helioseismology method. These measurements obtained throughout the mission allow study of their variations as a function of solar activity. It launched, along with the Prisma spacecraft, on 15 June 2010 on a Dnepr launcher from Dombarovskiy Cosmodrome, near Yasny, Russia. The mission, originally planned for two years, ended on 4 April 2014.

Objectives The objectives of the PICARD mission are to improve humanity's knowledge of:

the functioning of our star through new observations, the influence of the solar activity on the climate of the Earth.

History The PICARD mission was named after the French astronomer of the 17th century Jean Picard (1620–1682) who achieved the first accurate measurements of the solar diameter. These measurements are especially important as they were made during a period when the solar activity was minimum characterized by a sun nearly without sunspots between 1645 and 1710. This period was found by Gustav Spörer using sunspots observations gathered in Europe and this period is now named Maunder minimum. By comparing the diameter during the Maunder minimum and the diameter when the sun was active a variation has been found, leading to the still-unanswered question, "Are diameter and activity linked?" During this period in Europe, there was an unusually cold climate.

Platform PICARD used the Myriade microsatellite platform, developed by CNES to use as much as possible common equipment. This platform was designed for a total mass of about 120 kg mass at launch. Its attitude in space is maintained by using a star sensor, solar sensors, a magnetometer, gyrometers, several magnetic rods and reaction wheels. If an orbit control and orbit manoeuvres are needed, a hydrazine system may be used. The on-board management is centralised, and uses a 10 MIPS microprocessor T805. A mass memory is available for the data storage. The telemetry and telecommand used the CCSDS standard.

Payload The PICARD payload is composed of the following instruments:

SOVAP (SOlar VAriability PICARD): composed of a differential radiometer and a bolometric sensor to measure the total solar irradiance (previously called solar constant), PREMOS (PREcision MOnitor Sensor): a set of 3 photometers to study the ozone formation and destruction, and to perform helioseismologic observations, and a differential radiometer to measure the total solar irradiance, SODISM (SOlar Diameter Imager and Surface Mapper): an imaging telescope accurately pointed and a CCD which allows measuring the solar diameter and shape with an accuracy of a few milliarc second, and to perform helioseismologic observations to probe the solar interior.

References

External links PICARD mission website cnes.fr

Worked examples

Example 1 — a first encounter with Picard (satellite)

Start with the simplest possible case. Write down what Picard (satellite) 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 Picard (satellite) 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 Picard (satellite) 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 Picard (satellite)

In research: Picard (satellite) 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 Picard (satellite) 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: Picard (satellite) is common in secondary-school and first-year university syllabi. It links to neighbouring topics CNES satellites, Derelict satellites orbiting Earth, June 2010 in Russia, so understanding it makes those chapters shorter.
In everyday life: Look for Picard (satellite) 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 Picard (satellite) in 20 minutes

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

Frequently asked questions

What is Picard (satellite) in simple terms?

Why does Picard (satellite) 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 Picard (satellite)?

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 Picard (satellite).