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Space travel

Eagle Eye in Orbit

© NASA

07. April 2021

The International Space Station (ISS) races around the globe at 28,800 km/h at an altitude of 408 kilometres. Its mission: to explore the Earth, life on Earth, and the universe. Since June 2020, a special camera is in use on the station, taking some extremely high-resolution images of our planet. The SATLANTIS ISIM-170, which was developed in Spain, was put through its paces with the support of TÜV NORD subsidiary Alter Technology (ATN). For good reason, because conditions in space are harsh. In this interview, Innovation Manager Demetrio López explains what the project is all about and why the camera is helping us to understand life on Earth better  – yes, maybe even to make it that little bit better.

#explore: Mr López, what is so special about the ISIM-170?

It is a high-resolution multispectral camera for Earth observation microsatellites that weighs only 15 kilogrammes and has a very favourable mass/performance ratio. This means that it’s comparatively small and efficient and comes at a fraction of the costs of other instruments for Earth observation. The resolution, at less than one metre, is unique for space application domain.

But the conditions to which it is exposed are quite hostile, aren't they?

Yes, on board the ISS the camera has a lot to cope with. As well as the microgravity generated on the station, it’s exposed to extreme heat and cold cycles, vacuum, atomic oxygen and also high-energy radiation from the sun.

Which parts of the camera need to be exceptionally robust?

Its critical components include the optical front end, the semiconductor elements and an electronic subsystem for managing and controlling the payload. In view of the extreme environmental conditions, the electronics have been designed to work across the entire temperature and vacuum range. The overall design, by the way, is based on components from series production and we came up with suitable design and test requirements for it. The system must be designed to reduce potential mechanical and thermal stresses.

How did the tests go?

The components and modules were put through their paces in our laboratories in Seville and Tres Cantos. Under real operating conditions – that is, we simulated the actual environment you would find in space.

“To test the components and modules under real operating conditions, we simulate the actual space environment.”

Demetrio López, Innovation Manager at Alter Technology

All the tests were based on a special scheme that we developed ourselves and it is also applicable to equipment and small satellites.

Can you go into a little more detail?

The tests are specifically about all the stresses to which the camera components are exposed. These include, in particular, electromagnetic radiation, vibrations, sudden temperature fluctuations and the vacuum of space. We simulate all these in a lot of systematic test runs. The conditions are also important: The test environment must be very clean, like you get in a cleanroom, for the results to be valid. Incidentally, we were the first independent laboratory to be qualified by the European Space Agency.

And was it worth it, did the camera work as hoped?

The primary mission lasted three months, from June to September 2020. During this time, the camera orbited the Earth 1,400 times and covered more than 60 million kilometres. The calibration of the hardware at the start of the project went smoothly, and things carried on going well after that. In total, the camera took around 64,000 photos, which corresponds to a data volume of just over 450 gigabytes.

In other words, the technology works?

Yes, I would even say it works really well. We have gained a number of valuable insights for the production of durable and reliable components. It doesn't matter if you use them on Earth or in satellites or spaceships.

What’s the story with the photos? What use are they to us humans on Earth?

The camera took 20 pictures per second, for instance, of major cities, borders, coasts, nature reserves and the oceans. These photos make it easier to observe the seas and to spot, for example, oil pollution from ships, the spread of algal blooms or floating plastic. We can also track progress or delays in the growth of crops or the spread of fires. The bottom line is that the photos are making the analysis of the environment and the climate sounder and more comprehensive. In other words, the high resolution of the images is supporting the development of a fact-based environmental policy. The more we see, the more we know and the more wisely we can act.

About Demetrio López:

He is Innovation Manager at Alter Technology. The Spanish subsidiary of TÜV NORD is involved in numerous international space missions - currently, for example, in the Mars missions of ESA and NSA.