Delta III Launch Vehicle |
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Delta
III Status
A Delta III
successfully launched a
data-gathering payload — DM-F3 — on August
23, 2000.
Vehicle
Description
Boeing developed
the Delta III to fulfill growing customer needs
for a higher capacity commercial launch service. With a payload
delivery capacity to geosynchronous transfer orbit (GTO) of 3,810
kg (8,400 lb), Delta III effectively doubled the performance
of the Delta II.
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| Commonality
of Components
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Delta III is
derived from the Delta II, which has set a world standard for
reliability. Delta III shares a production line and many common
systems with Delta II, while adding elements to increase performance.
Propulsion
The Delta
III first stage is powered by the Boeing RS-27A main engine with
two vernier engines used to control roll during main engine burn,
as well as attitude between main engine cutoff and first-stage
separation. The RS-27A main engine also has been used on Delta
II for more than 10 years.
Boeing increased
the diameter of the first-stage fuel tank from Delta II to reduce
the overall length of the vehicle and improve control margins.
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To
add to Delta III first-stage performance, Boeing uses nine 1.17-m
(46-in) diameter Alliant Techsystems-built graphite-epoxy motors
(GEMs), which are derived from those on Delta II, but are larger
and produce 25 percent more thrust. Three of the new GEMs are
equipped with thrust-vector control to further improve vehicle
maneuverability
and control. |
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The new Delta
III second-stage Pratt & Whitney RL10B-2 engine is derived from
the RL10 power plant flown for more than three decades. This
second stage carries more propellant than Delta II and burns
cryogenic (cold) fuels, which produce more energy, allowing lift
of heavier payloads.
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 RL10B-2
Engine |
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Guidance
and Control
Delta III incorporates
the redundant inertial flight control assembly (RIFCA) avionics system
produced by L-3 Communications Space & Navigation
(formerly AlliedSignal Aerospace). The RIFCA uses ring-laser gyros and
accelerometers to provide redundant three-axis attitude and velocity
data. Flight software includes the standard flight program and a mission-constants
database specifically designed to meet the customer's requirements.
New
Composite Fairing
After developing a 3-m (10-ft) diameter composite fairing for
Delta II, Boeing adapted the technology to produce a new Delta III composite
fairing,
which is 4 m (13.1 ft) in diameter. In response to industry requirements,
Boeing encloses Delta III payloads within the fairing at the payload
processing facility before transporting the encapsulated payload
to the launch pad for launch vehicle integration.
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Typical
Delta III Mission Profile |
