Thor: Space Viking Meets Thunder God

Thor, the pre-cursor of the ASIM project, is a lightning monitoring experiment carried out by astronauts onboard the International Space Station (ISS). The project was initiated by the Danish ESA-astronaut, Andreas Mogensen, and has already delivered valuable data for climate research.

Denmark has long been an internationally recognised space-faring nation. The Danish geomagnetism satellite, Oersted, was launched in 1998, and the Danish x-ray space telescope JEM-X has been sending astrophysics data back to DTU Space from ESAs INTEGRAL satellite since 2002 - to mention just two Danish space missions. But one milestone was still lacking, until September 2nd 2015: a dane in space.

Space Viking

 Danish aeronautics engineer and spacecraft landing-systems researcher, Andreas Mogensen was chosen to train as part of ESA's astronaut corps in 2009, when the European Space Agency decided to take in a new batch of raw recruits - six in all, from France, Italy, Germany, England and Denmark. The aspiring astronaut had to wait until 2013 to get a mission assignment and has been in training for his 10-day mission ever since.

Short duration missions like Andreas' are a necessary part of the ISS programme of ultra-long duration missions, a year in length. Until this year the standard ISS mission lasted 6 months, with crews of 3 sent up in staggered shifts in the 3-person Russian Soyuz capsule which remained docked for the duration of their stay, both as lifeboat in an emergency, and transport on the way home again. However, Soyuz spacecraft can only tolerate about 6 months in space, thanks to the tough environment outside the Earth's atmosphere. So when ISS planners started talking about 1-year missions, a schedule of Soyuz flights to replace aging capsules had to be factored into the new programme.

Textbook Launch and National Jubilation

Andreas and his crewmates, a second generation kosmonaut Sergei Volkov and a Kazahk kosmonaut Aidyn Aimbetov, were sent to ISS in a textbook-perfect launch from Kazahkstan early on 2nd September, with Soyuz flight 18-M. Ten days later they braved the rapid return to Earth, in Soyuz flight 16-M, the old capsule that in March had taken two ultra-long duration astronauts to ISS. Scott Kelly and Mikhail Kornienko who have already been living and working on ISS for 6 months will continue on the space station for another 6 months, returning in capsule 18-M in 2016.

The launch, docking, hatch opening, live video interviews and return to Earth were all watched with enormous interest in Denmark, that can only be compared to the excitement and national pride last seen for the wedding of Denmark's crown prince and princess in 2004.

Thor: a Danish Experiment on ISS

Life on ISS however, does not include idleness, and with the 18-M capsule safely docked, the visiting astronauts had to settle down to an intense schedule of scientific experiments. Andreas was assigned a number of Danish experiments as well as other European projects, including testing a new form of water filtration system from Danish company, Aquaporin. But his biggest success came with DTU Space's Thor project.

Thor is a precursor of Denmarks hitherto largest space mission, ASIM. Andreas' brief consisted of photographing giant lightning strikes, in the hope of capturing the illusive flashes that travel upwards from the most violent thunderstorms to the edge of space itself. It sounds easy enough, but getting an astronaut to take pictures requires sending lists of target storms three days in advance of the photography session. Initially, Torsten Neubert, the scientific leader of the Thor project at DTU Space, saw Andreas' work simply as a way of checking the procedures, filters, exposure times and prediction system needed to ensure good pictures of likely storms. However, Andreas was so captivated by the project that he took the camera with him on breaks and continued filming on his free time.

Beyond All Expectations

There was much jubilation amongst DTU Space researchers when stills from Andreas' spare-time video were sent to the institute, because the industrious astronaut has managed to capture two beautiful examples of the giant lightning the group was hoping to see: a collection of red sprites, and a blue jet. These results far exceeded the group's expectations, and must be entirely credited to Andreas Mogensen's patience and enthusiasm.

Future ISS astronauts will continue the Thor project, notably frenchman Thomas Pesquet who starts a long-duration mission to ISS in 2016. But Thor is just the beginning of DTU Space's lightning research from the ISS. In February 2017 the Danish lightning recording system, ASIM, will be fixed to the underside of ISS to start 2 years of continuous monitoring of thunderstorms in both optical light and x-rays. The ASIM x-ray instrument builds on DTU Space's experience constructing x-ray cameras for astronomical purposes, such as the JEM-X space telescope on ESA's INTEGRAL satellite.

Adding Pieces to the Climate Puzzle

The giant lightning flashes being studied by the Thor and ASIM projects were discovered only 20 years ago, but hold the key to understanding the Earth's complex electrical circuitry that drives the storms and currents that churn up the atmosphere. As such they are very important for understanding and modelling the Earth's weather and climate. The Thor and ASIM projects are just two projects in DTU Space's extensive and varied research into the processes that drive the Earth's weather systems and mechanisms that are affected by climate change.

Related Links

 ESA blog for the iriss mission, about Thor and chasing storms


Torsten Neubert
Chief Consultant
DTU Space
+45 45 25 97 31


Olivier Chanrion
Special Consultant
DTU Space
+45 45 25 97 81