Tim Furniss/LONDON
The Boeing Delta IV's cryogenic first stage engine, the Rocketdyne RS-68, completed the last in a series of four "hot" test firings on 6 May. Attached to the Common Core Booster (CCB) at NASA's Stennis Space Center, Mississippi, the firing included a 303s burn.
The Delta IV will be launched on its maiden flight from Pad 37 at Cape Canaveral next March, and will mark the first mission by a US Air Force Evolved Expendable Launch Vehicle (EELV). Boeing is hoping that the flight will carry a commercial payload, an announcement about which is expected this month, says the company.
The second Delta IV is due to carry a US Air Force Defense Space Communications System satellite in May next year.
Four RS-68 hot-firings, lasting a total of 553s, simulated the launch of the Delta IV and tested propulsion, hydraulics and avionics.
The first firing in March lasted 15s. A test on 3 April burned for 145s, with the engine on full power and gimballed to the extreme. A third test ran for 90s, ending when the hydraulic system reached the test limit and an automatic shutdown was commanded.
Another RS-68 engine, not attached to the CCB, is also being tested at Stennis and will continue to be fired for 2,000s each month through to final qualification. The RS-68 has undergone 12,000s of testing so far.
The RS-68 programme was delayed when a fuel turbopump blade failed last year and a small redesign was required.
Source: Flight International