ESA PROBA-2: Five Years in Space: One Satellite, Three Missions

This artist's view shows Proba-2 fully operational in its final orbit. Its front side is continuously oriented toward the Sun, displaying instruments used for solar observation. 

LYRA (LYman alpha Radiometer) can be seen as the three vertical circles on the right. 

Just below it is SWAP (Sun Watcher using Active pixel system detector and image Processing), the grey surface in the right bottom corner.

In the center of the white panel, we can see the SPC (Solar Panel Concentrator), the two vertical triangle mirrors, and below it, the DSS (Digital Sun Sensor), the yellow grey box with a circular hole.


On the satellite's left side can be seen one of its three TPMUs (Thermal Plasma Measurement Units), the circular shape behind the solar panel, and the two extended DSLP (Dual Segmented Langmuir Probe) antennas extending from each corner of the solar array to study the space environment.

Credit: ESA

ESA's Proba-2 celebrates five years in orbit today. From technology demonstrator to solar observatory and now space weather platform, the mission has provided triple value to European scientists.

The second PRoject for OnBoard Autonomy (PROBA) mission was launched in 2009 as part of ESA’s programme for proving new technology in space.

Orbiting at about 725 km, this minisatellite, smaller than a cubic metre, carries four solar and space weather experiments and supports 17 technology demonstrations, providing companies with the flight experience that is essential for European industry to remain competitive.

In the first phase of its life, into early 2010, Proba-2 was extremely successful in verifying, under harsh space conditions, new technologies that will make future European missions more capable and efficient.

These included a new type of lithium-ion battery, an advanced data and power management system, combined carbon-fibre and aluminium structural panels, and new models of reaction wheels.

ESA’s Sun-watching Proba-2 minisatellite shows the aftermath of 18 February’s ‘coronal mass ejection’. 

Acquired at 0445 GMT, a little more than three hours after the initial eruption, the image demonstrates the Sun’s magnetic field reconnecting in the form of loops. 

Look down and left of the centre of the solar disc to clearly see this distinctive belt of loops.

Credit: ESA


Afterwards, Proba-2 continued as a solar observatory, a science mission studying the Sun and the plasma environment surrounding the satellite.

Information from the four solar and space weather sensors are helping scientists to understand our star’s corona and magnetic fields and the mechanisms responsible for solar eruptions.

This information is crucial to understanding ‘space weather,’ the conditions above Earth that can affect spaceborne and ground-based systems and services, or even endanger property and human health.

The importance of Proba-2 data for European space weather services meant that ESA’s Space Situational Awareness programme has been managing the mission since July 2013.

This programme is developing precursor space weather services. In particular, the solar data are used by the Solar Weather Expert Service Centre coordinated by the Royal Observatory of Belgium in Brussels.

This centre generates solar weather data products and services for various users throughout Europe, including industry, satellite operators and owners of sensitive ground infrastructure, such as power grids.

European Space Agency (ESA) sets a path for big space science

Europe has fixed a broad plan for the big space science missions it will launch over the next two decades.

It will likely lead to a large X-ray telescope being launched in 2028, and to an orbiting observatory to detect gravitational waves going up in 2034.

Together, these two ventures will cost in excess of 2bn euros (£1.7bn).

They join a mission already approved known as Juice, which will see a big satellite sent to observe Jupiter and its icy moons in 2022.

The path ahead was set by the Science Policy Committee (SPC) of the European Space Agency (Esa), which is meeting in Paris, France.

The committee's decision should now give clear direction and certainty to Europe's research and industrial base.

Fabio Favata

"These big missions take a long time to put together - of the order of 20 years," said Dr Fabio Favata, head of Esa's Science Planning and Community Coordination Office.

"Of course, when you fix things you trade flexibility for stability, but this gives the community the opportunity to plan. They now understand what will be the 'pillars', what will be the 'cornerstones'," he told reporters.

The SPC gathering was asked to approve a set of scientific "themes" that will guide the selection of Esa's next Large Class mission opportunities.

The agency tries to launch one of these flagship endeavours every six years.

The themes are titled the "hot and energetic Universe", and the "gravitational Universe".

And although these themes do not endorse a specific X-ray telescope or gravitational wave detection concept, their prescription is so tight that only two candidates can have real confidence of making it through the forthcoming selection process.

These are the two consortia that narrowly lost out to the Juice team in the last L-Class competition in 2012.

The Athena+ science instruments. Left: Design drawing of the X-IFU showing the Dewar and a zoom on the focal plane assembly. Right: Design drawing of the WFI.

The X-ray telescope proposal currently goes by the name of Athena+. It would be roughly four tonnes in mass and have a 12m focal length.

With a survey capability and sensitivity a hundred times better than today's best space telescopes, Athena+ would be used to study the origin of the monstrous black holes that reside at the centres of galaxies, among other objectives.

A Lisa-like observatory would detect gravitational waves using lasers fired across millions of km of space

It would fire lasers across millions of km of space to try to measure the disturbance in the fabric of space-time resulting from exploding stars and merging black holes.

The gravitational wave observatory, Laser Interferometer Space Antennagoes, (Lisa).

It is a concept that has been studied for the better part of 20 years already.

Indeed, ESA is about to fly a small satellite called Lisa Pathfinder to demonstrate some of the key technologies.

The agency will call for proposals to take the 2028 launch opportunity early next year. There will then be a design phase with various technical reviews before a formal adoption of a mission in about 2018.

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