• SOFIA – NASA and DLR's unique airborne observatory – will be based at Cologne Bonn Airport from 4 February to 16 March 2021.
• Prior to arriving at Cologne Bonn Airport, the Boeing 747SP, which has been converted into a stratospheric observatory for infrared astronomy, underwent a C check at Lufthansa Technik in Hamburg.
• The six-week research campaign in Germany is a first; SOFIA's usual location is the NASA base in Palmdale, California.
• Focus: Space

+++ SOFIA landed at Cologne Bonn Airport on 4 February 2021 at 15:33 +++

On 4 February 2021 at 15:40 CET, the airborne observatory of the German Space Agency at DLR and the US space agency, NASA, is due to land at Cologne Bonn Airport. From there, it will explore the night sky over Europe until 16 March.

"The SOFIA infrared observatory is one of the largest German-American projects for space exploration and underlines how important the cooperation with NASA is for us," explains Walther Pelzer, DLR Executive Board Member and Head of the German Space Agency at DLR. "We are enormously pleased that a full scientific flight campaign is now taking place from Germany for the first time since science operations began. SOFIA is scheduled to complete 20 flights with the German instrument GREAT, a high-resolution spectrometer, by mid-March, operating primarily over Western Europe."

"We are taking advantage of SOFIA's ability to observe from almost anywhere in the world to conduct compelling astronomical investigations," said Paul Hertz, Director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters in Washington D.C. "This observing campaign from Germany is an excellent example of the cooperation between NASA and DLR that has been the strength of the SOFIA programme for over 25 years."

"We are very proud that NASA and DLR have chosen Cologne Bonn Airport as the base for SOFIA's first German scientific flight campaign. This underlines the international importance of Cologne Bonn," said Johan Vanneste, CEO of Flughafen Köln/Bonn GmbH. "A 40-member project team, together with many external contributors, has meticulously prepared the campaign over the past weeks and months. A heartfelt thank you to all those involved – I am looking forward to a very exciting six weeks with an international team."

SOFIA reached full operation capabilities in 2014 and is used by about 50 international research groups. A unique component is the 2.7-metre telescope integrated into the fuselage of the aircraft for astronomical observations in the infrared and submillimetre wavelength range. These wavelengths are not visible from the ground due to being absorbed by water vapour in the troposphere; this is why SOFIA flies above an altitude of 12 kilometres. The telescope was developed and built by German engineers and scientists, and NASA brings the aircraft into the cooperation project.

SOFIA investigates the evolution of galaxies and how stars and planetary systems are formed from interstellar molecular dust clouds. The airborne observatory also regularly hosts two German far-infrared instruments, the German REceiver for Astronomy at Terahertz Frequencies (GREAT), a high-resolution heterodyne spectrometer, and the Far Infrared Field-Imaging Line Spectrometer (FIFI-LS).

During its time at Cologne Bonn Airport, an international team of German scientists and engineers will carry out astronomical observations with GREAT. The focus will be on the origin of cosmic rays and insights into the processes involved in the formation of massive young stars. Before the start of the campaign, SOFIA successfully completed a routine check at Lufthansa Technik in Hamburg that lasted several months. The telescope itself was also put through its paces.

20 scientific flights with the German instrument GREAT
SOFIA, the world's only airborne infrared observatory, will be stationed at Konrad Adenauer Airport located between Cologne and Bonn for about six weeks. During this time, the observatory will complete a total of 20 research flights with the GREAT instrument from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn and the I. Physics Institute at the University of Cologne. The flight routes go from Germany to the Atlantic, via Scandinavia to the Mediterranean.

GREAT explores the Universe
"We plan to fly four times a week, which will allow us to conduct a significantly higher number of investigations and thus deliver additional scientific results," explains Alessandra Roy, SOFIA Project Scientist at the German Space Agency at DLR. "Among the investigations are two large legacy projects. These are designed to provide large datasets on topics of current relevance and leave a legacy for years to come." The first of these legacy projects involves searching for gases in which a hydrogen atom has combined with another element, such as argon or oxygen, to form simple molecules called hydrides. The project aims to provide clues about density fluctuations in cosmic rays, high-energy charged particles that flow through the Milky Way. The second legacy project is dedicated to studying the interaction of massive stars with their environment. In doing so, scientists hope to understand how massive young stars destroy the clouds in which they are born.

The base for the SOFIA campaign will be Cologne Bonn Airport
"For me, as I was born in Cologne, it is particularly nice to have SOFIA 'on our own doorstep', so to speak," says Heinz Hammes, SOFIA Project Manager at the German Space Agency at DLR. "Cologne Bonn Airport was chosen because the necessary infrastructure is available there and the usually mild winter weather in the region around Cologne is very likely to allow undisturbed flight operations." The current significantly lower utilisation of the airport due to COVID-19 has made it possible to meet all the requirements of the German-American SOFIA team – from work and laboratory space to the necessary official night flight permit.

On the afternoon of 4 February 2021, SOFIA will take off from Hamburg, where the aircraft has been undergoing a C check at Lufthansa Technik since the end of September. This major maintenance takes place approximately every three years. During this check, the structure, technical systems, cabin and outer skin undergo a detailed inspection and are repaired if necessary. In addition to the routine testing and maintenance work, the performance of the air conditioning system was also increased to optimise the ambient temperatures for the sensitive research instruments. "We are very satisfied with the progress of the work and are now eagerly awaiting the scientific flights," says Heinz Hammes. At the end of the campaign, SOFIA will return to California, where preparations are already underway for the next flight campaign.

SOFIA
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a globally unique airborne observatory that investigates the Universe in the infrared spectrum. For example, the observatory investigates how galaxies develop and how stars and planetary systems are formed from interstellar molecular dust clouds. This is made possible by a 17-tonne telescope with a mirror diameter of 2.7 metres, developed and manufactured in Germany. SOFIA has six different scientific instruments available; three of these are from Germany – two observing far-infrared wavelengths and one observing optical wavelengths.

SOFIA is a joint project of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and the US National Aeronautics and Space Administration (NASA). The German contribution to the project is managed by the German Space Agency, using funds provided by the Federal Ministry for Economic Affairs and Energy (Bundesministerium für Wirtschaft und Energie, BMWi), the State of Baden-Württemberg and the University of Stuttgart. Development of the German instruments is funded by the Max Planck Society (Max-Planck-Gesellschaft; MPG), the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG) and DLR. German scientific operations are coordinated by the German SOFIA Institute (Deutsche SOFIA Institut; DSI) at the University of Stuttgart, and US scientific operations are coordinated by the Universities Space Research Association (USRA).

GREAT
The German REceiver for Astronomy at Terahertz Frequencies (GREAT) is an instrument for spectroscopic observations in the far infrared, at frequencies between 1.25 and five terahertz (wavelengths between 60 and 240 micrometres). These wavelengths are not accessible with ground-based observatories due to the lack of atmospheric transparency. GREAT is a first-generation instrument on board the SOFIA airborne observatory. It was developed and built by the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn and the I. Physics Institute at the University of Cologne in collaboration with the DLR Institute of Optical Sensor Systems in Berlin. The development of the instrument was financed with funds from the participating institutes, the Max Planck Society (Max-Planck-Gesellschaft; MPG) and the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG).