The High Altitude and LOng Range (HALO) Research Aircraft (based on a Gulfstream G550) is the research aircraft for atmospheric research and earth observation of the German science community. HALO was funded by the Federal Ministry of Education and Research, the Helmholtz-Gemeinschaft and the Max-Planck-Gesellschaft. The aircraft is operated by the Flight Experiments (FX) facility of DLR (Deutsches Zentrum für Luft- und Raumfahrt; German Aerospace Center) in Oberpfaffenhofen, near Munich. The concept behind HALO is to provide an optimal platform for airborne atmospheric science and Earth observation. A large set of jet aircraft candidates was investigated for its suitability. Finally the Gulfstream G550 was found to meet best the essential requirements of the future HALO users. The operational standby costs are shared by six German research centers and the DFG (Deutsche Forschungsgemeinschaft), which represents the German universities, together forming the HALO consortium. The HALO consortium partners are the main scientific users of the aircraft, but it is in principle also open to other users. 

In January 2001 the proposal for HALO was submitted to the Federal Ministry of Education and Research. On September 13, 2004 the German Ministry of Education and Research approved the construction and modification of the high-performance research aircraft. On February 16, 2005 the contract for the new aircraft was awarded to Gulfstream Aerospace Corporation. After a system review meeting with GAC in Savannah (April 19-20) completion of the green aircraft was in November of the same year. The HALO green aircraft was first flown on November 3, 2005 and the Certificate of Airworthiness was issued on November 7 for G550, c/n: 5093 (which was registered N593GA, January 2005). Wing modification took place in Savannah (GA) in 2006 with delivery of the green aircraft to RUAG at Oberpfaffenhofen (April 25, 2006) for modifications during 2006 and 2007. The Preliminary Design Review for HALO took place from May 8 to May 12, 2006 at the Gulfstream Facility in Savannah, a technical interface meeting from October 16 to 20. On December 8, 2007 the G550 was ferried back to GAC in Savannah (GA) for flight testing (June, July 2008), interior installation (July to September) exterior painting (September to October 2008), FAA / LBA inspection in November and acceptance at Savannah from December 2008 until January 2009.

Some HALO development pictures!

In January 2009 the aircraft was transferred back to DLR at Oberpfaffenhofen, fully painted and registered as D-ADLR. After a ground test period the first successful flight testing of the Basic Halo Measurement and Sensor System, including tower fly by and wing by wing flight with the DLR Falcon, took place on November 12 and 13. At the end of 2009 and beginning of 2010 (November 26 to January 30, 2010) the G550 was back in Savannah for maintenance and warranty works. Finally, on 28 October 2010, the first HALO flight with operational scientific instruments took place. Aboard HALO were instruments from the Forschungszentrum Jülich, the universities Leipzig, Mainz and Wuppertal and the DLR Oberpfaffenhofen. The years after the HALO G550 flew a lot of various missions all over the world for example for the POLSTRACC/GW-LCYCLE/SALSA mission.

Every year the 'DLR' (Deutsches Zentrum für Luft- und Raumfahrt; German Aerospace Center) organizes an open day for everyone interested in modern space exploration. The DLR has facilities in Cologne and Oberpfaffenhofen and this year the open day was held in the facility near Munich, which is known as the home of the European Galileo satellite navigation system control center. As the DLR HALO G550 research aircraft is also based in Oberpfaffenhofen this was the perfect opportunity to see this special mission aircraft up close. HALO was funded by the Federal Ministry of Education and Research, the Helmholtz-Gemeinschaft and the Max-Planck-Gesellschaft.