physics

Sodern

Sodern is a physics 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 Sodern rather than just read about it. In short: Sodern is a French company based in Limeil-Brévannes, near Paris in Ile-de-France, specialized in space instrumentation, optics and neutron analyzers. Its shareholders are ArianeGroup (90%) and the French Alternative Energies and Atomic Energy Commission (10%).

Key takeaways

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

Reference excerpt

Sodern is a French company based in Limeil-Brévannes, near Paris in Ile-de-France, specialized in space instrumentation, optics and neutron analyzers. Its shareholders are ArianeGroup (90%) and the French Alternative Energies and Atomic Energy Commission (10%). Sodern develops and produces instruments for space exploration missions or scientific programmes; satellite equipment; neutron generators and neutron interrogation tools. Since the 2000s, Sodern has participated in space exploration missions to Mars (NASA InSight, India Mars Orbiter, etc.), the moons of Jupiter (NASA Europa Clipper, ESA JUICE, etc.), Venus ( Japanese Mission "Planet C"), Ceres (NASA Dawn), the Moon, etc. It has developed high-tech scientific instruments including the heart of the PHARAO atomic clock, which should deviate by no more than one second every 300 million years, and will verify the effects predicted by the theory of general relativity. Sodern is one of the world leaders in the development and production of star trackers, instruments that allow satellites to position themselves in space, and neutron tubes. Called a "key actor" of national defense by French minister Jean-Yves Le Drian, Sodern develops and produces the neutron sources for the French nuclear force, part of the payloads of the French military satellites dedicated to Earth observation, GPS-free positioning systems, etc. Franck Poirrier, CEO of Sodern, is the representative of the space equipment manufacturers within COSPACE (French Ministerial Committee of Space Coordination).

History

Sodern was created in 1962 in the Philips' Laboratory of Electronics and Applied Physics (LEP) to launch a first generation of external neutron sources. In the late sixties, Sodern began to diversify its activities towards optical and high-tech space sensors, for which it is today the global leader. In the early 70s, on CNES demand, Sodern realized the first European Earth sensors, sensors dedicated to the attitude control of the experimental telecommunication satellite Symphonie (satellite). In 1975, the European Space Agency (ESA) subcontracted the manufacturing of multiple instruments for the Spacelab. Sodern created a high-precision system for measuring the spacecraft's attitude (orientation) and for fine-tuning its inertial reference. Sodern also delivered SED04 stars trackers for the Instrument Pointing System (IPS) of the Spacelab observatory. These sensors had a precision of 0.75 seconds of arc, thus the precision needed to see "a golf ball from a 10 km [6.2-mile] distance". Meanwhile, in the mid-1990s, Sodern enhanced its optical instrumentation activity dedicated to Space.

Activity Although Sodern activity started in the neutron area, by designing neutron sources for the French deterrent force, it began to diversify into optical sensors and advanced spacecraft instrumentation in the late 1960s.

Spatial Instrumentation Nowadays, its activities cover several ranges of space instruments. - Instruments for satellite attitude control: Earth and Solar sensors and stars trackers, equipping among others Spot, Helios, Eurostar satellites and M51 missile. The first Earth sensor was created in 1977 and boarded on Meteosat I. - Instruments for Earth observation (cameras, optical and optronic instruments for Spot satellites, Helios, Envisat, etc.). - Advanced optical instruments for the nuclear industry, the French deterrence force and scientific research, for example Astrium ATV videometers, that can guide its automatic docking to the International Space Station (ISS), and the Infrared Atmospheric Sounding Interferometer (IASI) instrument for MetOp. - Unique scientific instruments created on demand and integrated aboard satellites, space stations and space vehicles, such as PHARAO atomic clock (developed from the work of the Nobel Laureate Claude Cohen-Tannoudji), critical liquids on DECLIC orbit study instruments, some of the main components of the camera seeking for exoplanets aboard COROT satellite, etc.

Stars Trackers As a Star trackers worldwide leader, Sodern takes in 75% of the global market with two other European leaders, Galileo (Italy) and Jena Optronik (Germany). SED16 sensor has been the first to be used to replace gyroscopes in satellites. It was launched for the first time in May 2002 aboard Spot 5. It has since flown with numerous satellites, including the US communication satellite AMC 12 in February 2005. SED26, his almost similar successor, was launched in April 2005 aboard the satellite Apstar VI. The U.S. probe Dawn, that was made to visit two asteroids Vesta and Ceres, locates itself thanks to SED16 sensors. Those sensors are, within all Sodern's supplied equipment, those farthest from Earth in deep Space. The SED26 sensor guides, among others, the European Automated Transfer Vehicle ATV, the satellites Helios 2, Orbview 3 and 4, Sorce (from the American manufacturer Orbital), and more than a dozen satellites of the Russian manufacturer ISS-Reshetnev.

In June 2005, Sodern announced the development and production of Hydra sensors, more accurate, more compact and lighter than the SED. Development of the sensor was funded by the European Space Agency (ESA) and The French Space Agency (CNES), and resulted in a radiation-resistant sensor, about half as heavy as the SED (which had a mass of 3 Kg), which consumes only one Watt while operating and which has a precision of one arc second on each of its three axes. Sodern has sold more than a hundred of Hydra sensors so far, the first of which was launched in September 2012, aboard the French satellite Spot 6.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Sodern

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

In research: Sodern appears in physics 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 Sodern 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: Sodern is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aerospace companies of France, ArianeGroup, Companies based in Île-de-France, so understanding it makes those chapters shorter.
In everyday life: Look for Sodern 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 Sodern in 20 minutes

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

Frequently asked questions

What is Sodern in simple terms?

Why does Sodern matter?

Because it connects several physics 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 Sodern?

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 Sodern.