HALO ("High Altitude and Long Range Research Aircraft") was handed over to DLR in January 2009. Since then it has been the newest member of the DLR aircraft fleet and one of the most advanced research aircraft in the world.
HALO is based on a Gulfstream G550 business jet. Its combination of long range, maximum flight altitude (up to 15 km), payload and flexibility makes HALO to a worldwide unique research aircraft. With its operating range of more than 8000 km HALO is capable of performing missions on a global scale. Any region from the poles to the tropics and remote areas of the Pacific Ocean can be reached with HALO. Outside the tropics measurements can be performed in the transition region between stratosphere and troposphere.
The scientific payload of HALO is up to 3000 kg. Due to numerous modifications HALO is a real flying laboratory. There are more than 20 apertures in the fuselage for mounting of inlets. Openings with a diameter of about 50 cm are designed for optical windows. Hard points below the wings and the lower fuselage can carry scientific instruments outside the cabin, e.g. particle measuring probes.
The Institute of Atmospheric Physics is one of the most important scientific users of HALO. Here numerous instruments for the in-situ measurement of trace gas concentrations; aerosol and cloud properties have been developed for the operation on board of HALO. Remote sensing instruments like LIDAR can determine the concentrations of traces gases, water vapour and aerosol particles below and above the aircraft, respectively.
In cooperation with partners from universities, the Helmholtz-Association, the Max-Planck-Society and the Leibniz Association, the Institute of Atmospheric Physics investigates important scientific questions. In autumn 2010 HALO performed its maiden scientific flight during the so-called Techno-Mission. Further missions have been coordinated by the Institute of Atmospheric Physics. In 2012 during the ESMVal mission HALO was used for observations between the Arctic and Antarctic region to obtain data for the validation of Earth System Models. In 2014 ML-CIRRUS aimed at the investigation of ice clouds in the tropopause region. Further missions coordinated by partners like ACRIDICON were performed over the Brazilian rain forest and during NARVAL over the Caribbean.