The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

supply 25% more thrust, and three of the boosters are
equipped with thrust vector control for better maneuverability.
A new 4-m-diameter payload fairing tops the
assembly. The first Delta III was launched in August
1998 and, like the very first Delta, carried a real payload—the
Hughes Galaxy-X communications satellite—
rather than a test article. Unfortunately, it also suffered
the same fate, as a directional control problem doomed
the flight. The second Delta III launch, in May 1999,
also failed due to a rupture in the thrust chamber of the
RL10 engine. The third flight, on August 23, 2000, was
successful but carried only a test payload.
Although the Delta III has a backlog of about 20
launches, its manufacturer, Boeing, already has plans
Sample Delta Launch Vehicles
to phase it out in favor of the Delta IV. This latest
extension of the Delta dynasty, which uses a new liquid
oxygen/liquid hydrogen common core booster powered
by a single RS68 engine, is being developed under
the Air Force EELV contract. Delta IV comes in five
variants, ranging from the Delta IVM (medium), which
will replace the Delta II, to the top-of-the-line Delta IV
“heavy,” which combines three common core boosters
with a large Delta III-type LOX/LH2 second stage and
a new 5-m fairing to place up to 13,130 kg into GTO.
Together, the Delta IV variants are capable of replacing
not only the current Delta IIs and IIIs but also the
more powerful Titan IV. The maiden flight of the Delta
IV was scheduled for November 2002. (See table.)
Diameter First-Stage Payload (kg)
Length (m) Max. (m) Thrust (N)* LEO GTO
Original Delta 27.4 2.4 670,000 270 45
Delta A 27.4 2.4 760,000 320 68
Delta B 28.3 2.4 760,000 375 68
Delta C 28.3 2.4 760,000 410 80
Delta D 28.3 2.4 1,725,000 580 105
Delta E 29.2 2.4 1,644,000 725 150
Delta L 32.4 2.4 1,725,000 n/a —
Delta M-6 32.4 2.4 2,421,000 1,300 450
Delta 904 32.4 2.4 3,236,000 — 640
Delta 1914 32.4 2.4 3,362,000 — 680
Delta 2914
Delta 3000
32.4 2.4 3,362,000 2,000 720
Original 3000 32.4 2.4 4,321,000 — 950
With PAM-D 32.4 2.4 4,632,000 — 1,270
Delta 4914 39.0 2.4 5,337,000 3,400 1,360
Delta II 6925
Delta II 7000
39.0 2.4 5,339,000 3,980 1,450
7320 40.5 3.0 2,387,000 2,730 900
7925H-10L 40.5 3.0 5,382,000 5,090 1,830
Delta III
Delta IV
41.0 4.0 6,540,000 8,290 3,810
Medium 63.0 5.0 2,891,000 6,760 3,900
Medium-plus (4,2) 63.0 4.0 4,103,000 9,070 5,850
Medium-plus (5,2) 69.0 5.0 4,103,000 7,850 4,640
Medium-plus (5,4) 69.0 5.0 5,315,000 10,300 6,570
Heavy 70.7 5.0 8,673,000 20,500 13,130
*Includes any ground-lit or air-lit strap-ons.
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