The HALO (High Altitude and LOng Range) research aircraft is based on the ultra-long-range G 550 business jet produced by Gulfstream Aerospace. With a range of more than 8000 kilometres, measurements on the scale of continents are possible; the research aircraft can reach all regions, from the poles to the tropics and remote areas of the Pacific Ocean. Its maximum flight altitude of about 15 kilometres also allows for measurements in the lower stratosphere, outside the tropics.