Delta II 7920 10c
The Industry Workhorse
The Delta II program has a rich history. Over 29 years, the rocket
launched 155 times with 100 consecutive successful missions,
culminating in the final ICESat-2 flight for NASA.
Delta II has launched many memorable missions including
NASA’s rovers Spirit and Opportunity, the Phoenix Mars
Lander, all operational GPS missions through the constellation of
21 GPS II-R missions for the Air Force, and commercial missions
for Iridium, Globalstar and three DigitalGlobe satellites. This
tremendous achievement is a tribute to the dedicated ULA employees
and supplier teammates that ensure mission success is the focus of
each and every launch.
Payload Fairing
The Delta II launch vehicle offers the user a choice of three
fairings: a 2.9-m (9.5-ft)-diameter skin-and-stringer center
section fairing (bisector), and two versions of a 3-m
(10-ft)-diameter (bisector) composite fairing with two different
lengths. Each of these fairings can be used on either two-stage or
three-stage missions. The stretched-length 3.0-m (10-ft) composite
fairing, designated 10L, offers more payload volume. The stretched
3-m (10-ft)-diameter composite fairing has a reshaped nose cone
and a cylindrical section 0.91 m (3 ft) longer than the standard
3-m (10-ft) version.
Main Engine
A pillar of the American aerospace industry for more than four
decades, the RS-27A is second to none in its class featuring a
mature engine design and demonstrated manufacturing processes. The
RS-27A is a single-start, fixed thrust liquid bi-propellant gas
generator cycle main engine and two vernier engines. In addition
to providing vehicle roll control during flight, the vernier
engines each contribute more than 1,000 pounds of thrust to the
main engine.
Graphite Epoxy Motors (GEMs)
The Delta II 792X vehicle configuration includes nine Orbital ATK
solid rocket GEMs to augment first-stage performance. Six GEMs are
ignited at liftoff; the remaining three GEMs, with extended
nozzles, are ignited in flight after burnout of the first six.
Ordnance for the motor ignition and separation systems is fully
redundant.
Upper Stages
The second stage is powered by the flight-proven Aerojet AJ10-118K
engine. The simple, reliable start and restart operation requires
only the actuation of a bipropellant valve to release the
pressure-fed hypergolic propellants, with no need for a turbopump
or an ignition system. Typical two- and three-stage missions use
two second-stage starts, but the restart capability has been used
as many as six times on a single mission, for a total of seven
burns. During powered flight, the second-stage hydraulic system
gimbals the engine for pitch and yaw control. A redundant attitude
control system (RACS) using nitrogen gas provides roll control.
The RACS also provides pitch, yaw and roll control during
unpowered flight. The guidance system is installed in the forward
section of the second stage.
Depending on payload requirements, the Delta II series of launch
vehicles offers an optional spin-stabilized third-stage motor. The
flight-proven long nozzle Star 48B motor is produced by Alliant
Techsystems and uses a high-energy, solid propellant and
high-strength titanium cases featuring forward and aft mounting
flanges and multiple tabs for attaching external hardware. The
submerged nozzle uses a carbon-phenolic exit cone and a 3D
carbon-carbon throat. A spin table, containing small rockets,
mounts the third stage to the second stage and is used to spin up
the third stage prior to separation. The third-stage payload
attach fitting mates the third stage with the spacecraft.
United Launch Alliance
With more than a century of combined heritage, ULA has
successfully delivered 140 missions to orbit that aid
meteorologists in tracking severe weather, unlock the mysteries of
our solar system, provide critical capabilities for troops in the
field, deliver cutting-edge commercial services and enable GPS
navigation.