ASIM is being transported to ISS in a SpaceX Dragon spacecraft launched by a SpaceX Falcon 9 rocket from Cape Canaveral in Florida. (Photo: SpaceX)

ASIM background information, facts and partners

The ASIM mission is well under way to be send off to the International Space Station to investigate lightning and thunderstorms from space. Here you will find a lot of information about the ASIM-mission and its background. Each part can be read separately, so you can just zap around. There are also links to more in-depth information on ASIM.

Launch of ASIM:

ASIM was launched 2. April 2018 at 22.30 CET (UTC/GMT + 1). ASIM was being transported in a SpaceX Dragon spacecraft launched by a SpaceX Falcon 9 rocket from Cape Canaveral at NASA's Kennedy Space Center in Florida, USA, onboard the SpaceX CRS-14 Cargo Mission to International Space Station, ISS.

The mission in short:

ASIM is an international mission of the European Space Agency, ESA, that will observe gigantic lightning flashes and high-energy radiation from severe thunderstorms in unprecedented detail.  From the vantage point of the ISS, the advanced ASIM instruments will look down towards the Earth, observing what happens in the atmosphere above thunderstorms from the top of clouds up to 100 km above Earth. 

The instruments will record optical images of lightning, count photons and measure X- and Gamma-radiation associated with the thunderstorms. They will also observe water vapor, clouds and aerosols, and their interaction in the atmosphere and possible impact on climate processes. ASIM will also detect meteors that enter the Earth’s atmosphere.

The measurements will both provide new insight in phenomena connected to thunderstorms as well as knowledge that might improve future climate models. The new understanding of electrical discharges will contribute to development of improved lightning safety systems and new technologies for industrial production.

The main industrial contractor is the Danish aerospace company, Terma, and the scientific leadership is at the Technical University of Denmark, DTU Space.  Terma has developed the optical cameras  and DTU Space the MMIA photomultipliers and the instrument computers. DTU Space also leads the X- and Gamma-ray instrument consortium of University of Valencia, Spain, University of Bergen, Norway, and Space Research Center, Poland. OHB-Italia, Italy, delivered the platform computer.

The Danish Ministry of Higher Education and Science has also supported the ASIM project.

The mission duration is minimum 2 years.


ISS is an ideal place to observe the thunderstorms from:

ASIM is now mounted outside the ESA Columbus module of ISS looking down at the Earth. The ISS is the best space platform for thunderstorm observations because the orbit at about 400 km altitude is close to the Earth. It also covers +/- 51.6 degree in latitude and therefore all of the major thunderstorm regions.


Red lightning were seen as omens in the past:

Thunder and lightning has probably always fascinated human beings. The Etruscans in ancient Italy are said to have known of ’red lightning’ and considered them as 'omens’. That could have been a ‘red sprite’ observed and documented scientifically only in the 1990s.

The first to study electricity was the English physicist William Gilbert in the 1500s. In the 1920s British scientist and Nobel laureate C.T.R. Wilson predicted that electrical discharges can occur above thunderstorms in the mesosphere, and that thunderstorm electrical fields can accelerate electrons to relativistic energies.

Wilsons work sparked many experiments to measure X- and Gamma-rays from thunderstorms. But the instruments were not sensitive enough to measure the radiation. And the lightning on top of the clouds moving upwards are difficult to distinguish from the more common known ones that moves downwards against the Earth.


There are different types of lightning:

In 1990, everything changed, when the first observation of a discharge  in the mesosphere was described by scientists. The phenomenon was documented first on video tape in 1989 and then described in Science 1990 by Dr. Robert Franz - who filmed what is now known as a red sprite - and colleagues from University of Minnesota. From then a wealth of new types of discharges above thunderstorms have been discovered from ground and aircraft observations. And X- and Gamma-radiation has been observed from spacecraft in low orbit. The first sprite observations over European thunderstorms were taken in 2000 from Observatoire Midi Pyrenees and the first from space in 2001 by the LSO instrument on the ISS.

Now we know that there are different types of these lightning in space 20-100 km above Earth. Apart from red sprites we have discovered blue jets and the very large gigantic jets that reaches up to the ionosphere at the edge of Space 90-100 km above the Earth. These phenomena are called Transient Luminous Emissions (TLEs).

X- and Gamma-radiation have been observed during thunderstorms from satellites in low orbit and aircraft. This radiation is called Terrestial Gamma-ray Flashes (TGFs). 
The new discoveries, some predicted by Wilson, are at the core of the ASIM mission. The project were initiated after the sprite discoveries in 2000.


ESA astronaut involvement:

As a pretext for the ASIM-mission the Danish ESA astronaut Andreas Mogensen took part in DTU’s project THOR during his mission to ISS in 2015. Here he documented unique lightning with his optical camera. From the ground control centre in the US he has also been involved in the mounting of ASIM on the outside of ISS.


The ASIM instruments:

The instruments on ASIM (The Atmosphere-Space Interactions Monitor) are designed to measure bursts of Gamma-rays from thunderstorms. These are called Terrestrial Gamma-ray Flashes (TGFs) and are of millisecond duration. It is the first time that a sensor designed to observe TGFs is flown in space. Optical instruments observe lightning and high-altitude lightning such as red sprites, blue jets and gigantic jets. The common name for these are Transient Luminous Emissions (TLEs). They are of millisecond-to-second duration.

The instruments are;

MXGS (Modular X- and Gamma-ray Sensor). The 2 sensors measures the energy and time of arrival of photons with energies from 20 keV to 20 MeV. The instrument can also identify the angle of arrival of photon bursts (TGFs) and hence pinpoint the region of the thunderstorm that has generated them.

MMIA (Modular Multispectral Imaging Array) measures optical emissions. This is done by 2 cameras at 337nm and 777nm wavelength, with 5nm bandwidth (at 1 Mpixel, 12 frames per second, 400m spatial resolution at the surface of the Earth. Both cameras have light sensitive CCDs and can only operate at night.

There are also 3 photometers (non-imaging photon counters) working at 180-777 nm. They count photons 100,000 times a second. The instruments run continuously and the instrument computers detect sudden increases in the photon flux. If the increase is above a predefined level, data from all sensors from a period before and after the event are saved and sent down to Earth for analysis. 

More details on the science:

High-energy radiation and high-altitude lightning.
X- and Gamma-radiation comes from electrons that are accelerated to high energies by electric fields of thunderstorms as they zip through the atmosphere. ASIM gives measurements that allow us to understand how electrons are accelerated to such energies, and in such numbers that the radiation can be observed from satellites at 4-500 km altitude. This is still unknown.

The discharges of the stratosphere and mesosphere take many forms. ASIM helps us to understand what determines their type and structure. We can then begin to understand the influence of local conditions in the stratosphere and mesosphere, where the discharges occur, relative to the electrical properties of the thunderstorm battery, which power them. If we understand the difference, we can learn more about thunderstorms, clouds and the fine-structure of the stratosphere and mesosphere, of which little is known.


X- and Gamma-radiation represent a new window into the inner workings of lightning, which are difficult to measure. High-altitude lightning allow us to study lightning without the obscuring clouds. With ASIM we will better understand the complex processes of lightning. This can improve lightning detection technologies and lightning protection strategies.

Atmosphere and climate.

Lightning and high-altitude lightning affect the concentration of atmospheric gasses that are important for the climate processes. By understanding lightning better, we can improve models of chemical changes and ultimately reduce uncertainties in the global influences of thunderstorm activity on the gas concentrations.

Interactions with the space environment.

The instruments of ASIM also detect meteors that enter the Earth’s atmosphere. The measurements give a global and seasonal characterization of the influx helping understand their origin and their interactions with the atmosphere, and will assist in the recovery of meteors that reach the Earth’s surface as meteorites. Meteors are messengers from outer space. Analysis of samples help us understand the formation of our planetary system.

How the data get useable for scientists.

The Belgian User Support and Operations Centre, B.USOC, in Brussels is the control and command centre for ASIM. It receives ASIM data from the ISS, check them for instrument anomalies and pass them on to the ASDC based at DTU Space in Denmark. ASDC conducts the scientific data processing and evaluates the instrument performance. In addition to data processing, ASDC distributes data to the scientific community. The Birkeland Space Science Centre of the University of Bergen provides the software for MXGS calibration. The Image Processing Laboratory at the University of Valencia provides software to identify the angle of arrival of TGFs.


Partners and collaboration:

ASIM is developed by ESA within the Directorate for Human Spaceflight and Operations.

The main industrial contractor is Terma, Denmark, leading the industrial consortium. The main partners and responsibilities are: DTU Space, Denmark; Scientific leader. Leader of the MXGS consortium. Responsible for the MMIA photomultipliers and the MXGS and MMIA computers.Terma, Denmark; Responsible for the MMIA cameras. University of Valencia, Spain; MXGS mechanical structure and instrument application software. University of Bergen, Norway; The MXGS detectors. Space Research Center, Poland; the MXGS power supply. OHB-Italia, Italy; the ASIM payload computer.

The Danish Meteorological Institute (DMI) provides global meteorological data for the project and assist in intrepret them scientifically.

The Danish Ministry of Higher Education and Science  has supported the ASIM project through different funding initiatives - among them a special contribution through 'globaliseringspuljen' in 2009-2012 for climate research activities through the European Space Agency, ESA. This initiative made it possible to strengthen both the development and implementation of Danish front edge technology as well as the cooperation between universities and private entreprises.

The ASIM Facility Science Team (FST) advises ESA on issues related to science, technical requirements and observations. The FST members are:

Dr. Torsten Neubert, DTU Space (Chair).
Professor Nikolai Østgaard, University of Bergen.
Professor Victor Reglero, University of Valencia.
Dr. Elisabeth Blanc, CEA, France.

In total some 80 research groups from 30 countries are involved in the scientific exploitation of the data generated by ASIM. ESA supports the ASIM Topical Team, a collaboration of groups primarily in ESA member states.


Find out more about the science in the ASIM project:

Climate processes 

Earth's surface and the atmosphere

Interactions of space processes with the atmosphere

Testing new concepts and technologies related to ASIM 



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


Morten Garly Andersen
Responsible for Communication
DTU Space
+45 45 25 97 69


Carol Anne Oxborrow
Special Consultant
DTU Space
+45 45 25 97 33