 Qualification tests were completed in 1983 and this upgraded variant was designated HM7B.It was also used on the Ariane 4 vehicle's upper stage where the burn time was further increased to 780 seconds, and since 12 February 2005 it's also used on the upper stage of Ariane 5 ECA.The HM7B is a regeneratively cooled gas generator rocket engine fed with liquid oxygen and liquid hydrogen.