http://www.aviationnow.com/avnow/new...s/08094wna.xml


The flight marks only the third mission for the Delta II Heavy
configuration, which features nine ATK solid rocket boosters substantially
larger than those on the standard Delta II. The mission had only a 12-sec.
launch window, but notched Delta's 60th consecutive launch success (see
photo p. 20).

The Delta II/Messenger vehicle lifted off at 2:15 a.m. EDT on 1-million-lb.
thrust from its six ground-lit solids and its Rocketdyne RS-27
oxygen/kerosene first stage core, followed by ignition of the three air-lit
solids.

Its second stage 10,000-lb.-thrust Aerojet AJ10 engine then ignited at Mach
21 to propel the vehicle to 17,500 mph. and an initial 104-mi. parking
orbit for a 37-min. coast across the Atlantic and southern Africa.

This set up the launcher for a twin-burn Earth-escape maneuver which
started over the Indian Ocean west of Australia where the Aerojet engine
was ignited for a second time.

The 3-min. firing placed the vehicle into a temporary high-energy
elliptical orbit to provide much of the escape velocity. The burn was
monitored by a special portable U.S. Air Force tracking station on a
commercial ship off Australia.

IMMEDIATELY after second stage shutdown and separation, six 500-lb. thrust
Atlantic Research spin rockets were fired to rotate the third stage and
Messenger to just over 60 rpm. for guidance stabilization.

With the vehicle both spinning and accelerating upward, the 15,000-lb.
thrust third stage ATK Star 48 motor was ignited for 75 sec. to increase
speed to 25,000 mph.

At shutdown, the third stage then ejected two fist-sized weights attached
to long cables. Much like a spinning ice-skater extends her arms to slow
down, this yo-yo de-spin system transferred the angular momentum of the
spinning vehicle to the weights, reducing the spin to under 2 rpm. within 5
sec.

These events were monitored by a commercial Universal Space Network station
at Dongara and another USAF portable station at Exmouth, both on the
western Australian coast. The 2,424-lb. Messenger spacecraft was then
separated from the third stage over eastern Indonesia.




Herm
Astropics http://home.att.net/~hermperez