Boeing's made its first successful launch on August 21 , 2000 . Of its three flights, two have been failures, and the third - which succeeded - carried the only dummy (inert) payload of any Delta Rocket . Delta III has the capability to deliver 8,400 pounds (3,800 kilograms) of cargo to Geostationary Transfer Orbit , twice the payload of the Delta II.
A Delta III has the kerosene/oxygen first stage of a Delta II. However, the complex and less-efficient stack of upper stages has been replaced with a more advanced hydrogen/oxygen stage. The boosters are noticeably larger. The new fairing fits the larger payloads possible; the first stage has been modified to accommodate the larger stack.
- The upper stage burns high-performance Cryogenic Fuel in a proven Pratt & Whitney RL10 engine design. The liquid-hydrogen tank is 4 meters in diameter, covered in insulation derived from that of the Space Shuttle External Tank , and built by Mitsubishi Heavy Industries. The separate liquid-oxygen tank retains the 2.4 m diameter of previous Deltas. Both are structurally stable. The RL10 engine, from the Centaur upper stage, is in the new RL10B-2 configuration, with an extending nozzle. The nozzle fits in the vehicle stack for launch, then extends in space to increase expansion ratio and improve efficiency. The extending segments are uncooled carbon composites, made by SEP of France.
- The solid rocket boosters are Alliant GEM-46s, sometimes referred to as GEM LDXL (Large Diameter Extended Length). These are 14.7 meters length and 46 inches diameter, versus 13 meters and 40 inches for the GEMs on Delta II. Six are ignited on the launch pad, three are lit in midair. To maintain enough steering authority, three of the boosters have Vectoring Nozzles .
- The payload fairing is a new design in composite materials, matching the upper stage hydrogen tank at 4 meters diameter.
- To keep the vehicle at a reasonable length and avoid steering problems in high-altitude crosswinds, the first stage is shortened. The kerosene (RP-1) fuel tank, formerly 8 feet in diameter like the liquid oxygen tank, is now a squat 4 meters, like the hydrogen tank. It too is made by Mitsubishi Heavy Industries. The new length also minimizes changes to the launch tower.
In keeping with the 4-digit designation system from the Delta II , the Delta III is technically referred to as the 8930.
Overall, payload to GTO (Geostationary-Transfer Orbit) has doubled versus a Delta II, with reasonable program costs and streamlined operations. Technologies and components from the Delta III also contribute to the Delta IV. However, the consecutive failures of the initial Delta IIIs, the more-advanced Delta IV program, and successful Sea Launch venture, left the Delta III as an interim vehicle only.
- The inaugural launch on 27 August 1998 from Cape Canaveral Air Force Station ended in failure, when software adapted from the Delta II caused a guidance failure during first-stage flight. The failure and subsequent vehicle motion depleted the hydraulic fluid used for steering. Upon loss of control, the vehicle was destroyed. The Galaxy X satellite ( Hughes HS601 HP type) crashed in the Atlantic Ocean.
- The second launch on 4 May 1999, also from Cape Canaveral, also ended in failure. The second stage engine experienced a pressure anomaly and rupture, and shut down while its second burn was underway. The Orion 3 satellite (Hughes HS601 model) was stranded in a useless orbit.
- The third flight on 23 August 2000, launched the DM-F3 payload. This was a dummy designed to mimic an HS601 communications satellite, and equipped with sensors to monitor vehicle characteristics. Final orbit was slightly low (20,600 km instead of 26,000), but was within margins and considered a success.
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