The Dassault Falcon 20E (registration D-CMET) has been extensively modified for use in research by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). The DLR flight facility in Oberpfaffenhofen primarily uses it for atmospheric research. International research teams measure trace gases and aerosols directly from on board the aircraft, and they collect air samples for subsequent laboratory analysis. This twin-engine jet is based on a business aircraft produced by French company Dassault. It can fly at altitudes of up to 12 800 metres.

The research aircraft has been in use since 1976. Over this period, it has become one of the most important German and European airborne research platforms for observing the Earth and its atmosphere. In over 30 years of deployment in environmental and climate research, the aeroplane has acquired a leading position among European research aircraft. The Falcon 20E therefore also plays an important role in the EUropean Fleet for Airborne Research, (EUFAR), an initiative bringing together 28 leading European institutions and companies in the field of airborne research.

A flying laboratory for environmental and climate research

The Falcon can fly at higher altitudes than most airliners. It is extremely robust and versatile, so that measurements can even be performed in the proximity of thunderstorms or at a distance of just 30 metres behind the engines of an airliner. The Falcon's flight ceiling is sufficiently high for it to reach the lower stratosphere at mid-latitudes, which in recent years has become a focal point for research into ozone depletion.

Over the Norwegian mountains, for instance, measurements were performed on polar stratospheric clouds. During cold winters, these clouds significantly contribute to ozone depletion. Over the past few years, the Falcon has been one of DLR's most important research facilities for exploring the effects of aircraft emissions on the composition of the atmosphere. Its unique modifications and features make it a true multipurpose platform for research applications, and one which can be configured to meet individual needs.

Modifications

In its current form, the Falcon can accommodate a payload of up to 1 100 kilogram of scientific instruments. The instruments are mounted inside the cabin and underneath it, as well as under the wings.

Among other things, they include a flow measuring device, the so-called nose boom and antennas which can be mounted on the exterior of the aircraft.

In the top and the bottom of the fuselage, the Falcon has special optical windows for cameras and LIDAR systems (Light Detection And Ranging) used for atmospheric measurements. A LIDAR emits a laser pulse and then captures the signal as it is scattered back by the atmosphere. This allows the deduction of concentration profiles of water vapour, ozone or aerosol particles above or below the aircraft's flight altitude. For radar antennas, a side window can be replaced by a special disk.

The Falcon's avionics systems are continuously adapted to the meet the increasing requirements of scientific experimentation and of flight safety. This enables precision navigation and allows the unrestricted global deployment of the aircraft.

The following modifications and additions have been made to the Dassault Falcon 20E D-CMET's aircraft structure:

• Nose boom with integrated flow probe for measuring inflow velocity and direction of inflow
• A total of three special windows in the roof and the floor of the fuselage which can for instance be used for the deployment of LIDAR instruments for atmospheric measurements. The lower special windows can be protected against debris damage during take-off and landing by a roller door.
• New engines with additional power generators for supplying power to experiments (2x300 ampere at 28 volt)
• four small openings (with a diameter of eight centimetres) in the top of the fuselage
• four underwing hardpoints for carrying particle measurement systems (PMS)
• Central hardpoint on the bottom of the fuselage for carrying various measuring containers
• Side windows for infrared and radar antennas, so-called microwave measuring equipment
• Hardpoints on the lower aft section of the fuselage for carrying radiometers

Missions - Research focus

Measuring the formation and structure of arctic storms

In connection with the International Polar Year (IPY) 2007/2008, scientists of the DLR Institute for Atmospheric Physics (DLR-Institut für Physik der Atmosphäre) measured the formation and structure of arctic storms over the Norwegian Barents Sea in February 2008. These activities were part of the IPY-THORPEX project, supported by the University of Oslo (Norway), EUFAR and DLR.

The Falcon was equipped with modern remote sensing instruments; a newly developed LIDAR, the first capable of measuring aerosol and water vapour profiles with all four wavelengths, and the Doppler LIDAR which provided the scientists with wind profiles below the aircraft. The water vapour LIDAR that was used functions as a prototype for future space missions.

In a total of 13 missions, the life cycle of polar low-pressure systems, arctic fronts and orographically modified flows in northern Norway and Spitsbergen was investigated. Such measurements are performed only very rarely in the Arctic, a region especially badly affected by climate change. The unique nature of the data obtained will present scientists with fascinating challenges in the years to come.

SCOUT campaign - measuring climate change

How will the composition of the atmosphere and the climate develop in the future?

Within the framework of the five-year EU project SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere), researchers of the DLR Institute for Atmospheric Physics, staff of the DLR flight facility, and 60 European research institutes and universities will examine these questions in great detail. Working with its international partners, DLR performed extensive measurements with the Falcon during field research in Australia in November 2005.

One of the aims of this campaign was to provide evidence that in tropical thunderstorms aerosols are transported up from air layers close to the ground into the stratosphere, reaching altitudes of more than 18 kilometres. These trace substances stay there for many years. They are distributed around the globe and they influence the ozone layer.