Rocketdyne worked with DaimlerChrysler Aerospace in developing the Aestus-2 storable-propellant, restartable upper-stage engine, which began test firings at Lampoldshausen (Germany) early in February 2000 and was subjected to a second six-week test series run by Rocketdyne in March/April of the same year at White Sands (USA). Aestus-2 was being developed with private funding by the two companies, allowing it to be marketed to all potential users. Its principal potential use was in Ariane-5’s new Versatile upper stage. At 60 kN, Aestus-2 has twice the thrust of the current Aestus upper-stage engine of Ariane-5. When used with the new Versatile upper stage, Aestus-2 could boost the advanced Ariane-5’s payload to geostationary orbit from 8,000 kg to 8,600 kg, in addition to providing the mission flexibility offered by a restartable engine.