by Ed Kyle
Atlas SLV-3D Centaur D1AR AC-51 Launched Pioneer 13
to Venus from Cape Canaveral LC 36A in 1978.
Atlas was the first U.S. intercontinental ballistic
missile, but its ICBM service was short-lived. Atlas served longer as an orbital
launcher stage. It was best known for powering NASA's original Mercury orbital
missions, but it far more often launched unmanned missions with Agena or Centaur or other
Atlas, built by San Diego's Convair (later General
Dynamics) was the "balloon tank" missile. Its stainless steel propellant tank
walls were as thin as a dime in some areas and had no internal structural support.
Instead, the walls were supported by internal pressure, much like an unopened carbonated
beverage can. Atlas was powered by a unique stage-and-a-half propulsion system that
consisted of a jettisonable "booster package" with two powerful Rocketdyne
(Y)LR89-NA5(7) engines positioned on each side of a less-powerful, but more fuel efficient
and light weight, Rocketdyne (Y)LR-105-NA5(7) sustainer engine. Two small verniers,
mounted on opposite sides of the vehicle above the booster package, provided roll control
and trajectory tuning. All five engines ignited on the pad.
Numerous Atlas and Atlas-based variants flew during the
program's nearly 50 years duration. A total of 576 launch attempts were made with
Rocketdyne-powered Atlases, not including a couple of vehicles destroyed in pre-launch
propellant loading accidents. Atlas launched the first U.S. manned orbital flights,
the first spacecraft to fly by another planet, the first to orbit another planet, the
first to fly past the outer gas giant planets, and the first U.S. spacecraft to impact,
land on, and orbit the Moon. Centaur, which flew atop Atlas in 1962 with a first success
in 1963, was the world's first liquid hydrogen-fueled upper stage. Atlas-Agena D was
the launch vehicle for numerous Gambit KH-7, a USAF reconnaissance program that was as
large or larger than the U.S. Gemini program.
Atlas 2/2A/2AS were the final Rocketdyne powered
Atlases, by the end produced by Lockheed Martin in Waterton Canyon, Colorado.
AC-164, launched December 2, 2003, was the last heritage Atlas of 284 launched from
Vandenberg AFB/Point Arguello since 1959. On May 14, 2004, Lockheed Martin rolled
rolled out AC-167, the final Atlas 2AS, shipping it to Cape Canaveral on May 16. On August
31, AC-167 closed out the heritage Atlas program with a successful launch from Space
Launch Complex 36A with a National Reconnaissance Office satellite.
Six Atlas 3 launch vehicles finished
the balloon tank Atlas era. They dispensed with the stage-and-a-half design, using a
"Single Stage Atlas" powered by a single dual chamber RD-180 engine built in
Moscow by Energomash. The final Atlas 3 flew on February 5, 2005.
Atlas 5, which used an all-new structurally stable first
stage, was for all practical purposes an "Atlas" in name only.
"Baseball Card" type details of most of the
flown Atlas variants are provided in the following links, listed in approximate
1. Atlas ICBMs (Atlas
Atlas in its original ICBM form. Atlas D was the first operational version, fitted with Mk
2 and Mk 3 reentry vehicles (RVs). Atlas E and F with Mk 4 RVs and inertial guidance
were the ultimate ICBM variants. Atlas E was based in above ground horizontal
"coffin" shelters with retractable roofs. Altas F was based in vertical
silos fitted with an elevator that lifted Atlas to the surface for propellant loading.
Note that the intertank was moved for Atlas C and later, enlarging the LOX tank and
shrinking the RP-1 tank compared to the original design. Atlas D served as the starting
point for subsequent space launch vehicle variants.
2. Atlas 10B
SCORE (Signal Communications by Orbiting Relay
Equipment) was famously launched by Atlas 10B from Cape Canaveral LC 11 on December 18,
1958. The entire Atlas sustainer stage boosted itself to a 159 x 1,187 km x 32.29 deg
orbit. The usual 1.5-ish tonne RV was replaced by a lightweight nose fairing. The
sustainer and 68 kg of additional SCORE hardware weighed 3,969 kg. It was the first
orbital Atlas, and only the fifth U.S. orbital success. It was also the very first U.S.
Air Force orbital success.
10B got to orbit in a hurry, and endured some high-g forces before SECO to get there.
It played the very first human voice (from a recording) ever sent from an American
satellite to the ground. SCORE demonstrated a basic store and forward capability.
Recordings could be uplinked to a tape recorder, and then played back down. SCORE's most
famous transmission was a pre-recorded holiday message to the world from U.S. President
Atlas-Able was the "least successful" U.S.
launch vehicle. NASA, formed in October 1958, needed interim launch vehicles
immediately. Atlas-Able was created by adding the already developed Vanguard
("Able") second stage. Schedule slips thwarted plans for it to launch
Pioneer to Venus in June of 1959. The Agency settled on a lunar orbit plan instead.
The intricate STL Pioneer P satellites that resulted were advanced for their time, with
built-in thrusters to insert themselves into lunar orbit.
The first Atlas Able (Atlas 9C) was destroyed in an FRF attempt at LC 12 on September 24,
1959. Helium improperly injected into the sustainer fuel pump line due to a configuration
error caused cavitation, overspeed, shutdown after 2 seconds, and a sustainer propellant
duct failure that fed a fire in the Atlas engine section. The tanks soon failed and
the vehicle exploded. No satellite was on-board.
Atlas 20D Able 4B launched from LC 14 two months later, but the payload fairing failed 45
seconds after liftoff. The design neglected to provide a means of equalizing air pressure
inside the fairing. Atlas 80D Able 5A came nearest success on September 25, 1960,
when Atlas burned out and Able ignited its AJ10-103 engine. Unfortunately Able failed
after 67 seconds due to an oxidizer system problem in the pressure fed stage. Atlas
91D Able 5B failed on December 15, 1960 when the Able stage ignited early, at T+70
seconds, while the Atlas booster burn was still underway.
4. Atlas LV-3B
Atlas LV-3B Mercury put John Glenn, Scott Carpenter, Walter Schirra, and Gordon Cooper
into orbit, not to mention chimpanzee Enos. LV-3B was an Atlas D modified with an Abort
Sensing & Instrumentation (ASIS) failure detection system and, after the MA-1 failure,
with a beefed up tank section near the spacecraft adapter. Other changes included
simultaneous SECO/VECO, lightweight telemetry, and redundant autopilot.
Three of the first four launches, including the precursor Big Joe flight, suffered some
type of failure. Atlas itself was still only succeeding during a little more than half of
its flights. Still Glenn and the others climbed aboard without hesitation. Crazy? Maybe a
little. Brave? Absolutely. National heroes? They gave astronauts ticker tape parades and
medals back then.
5. Atlas LV-3A
Atlas LV-3A Agena A only flew four times during 1960-61.
It was a stop-gap measure until the larger Agena B stage came on line. Agena A, also
flying on Thor at the time, was troubled at this stage. Lockheed was still climbing the
spaceflight learning curve. Two launches with MIDAS payloads (precursor IR missile sensing
satellites) took place from the Cape. Atlas and Agena collided at staging on the first
attempt. The second launch made it to orbit, but Agena soon tumbled out of control. Two
subsequent launches carried SAMOS payloads from Vandenberg AFB PA 1-1 (today's mothballed
SLC 3W). Agena failed on the first try. The second made it to near polar orbit. SAMOS took
photographs, then scanned the photos and transmitted them by radio. Image quality turned
out to be insufficient for reconnaissance.
6. Atlas LV-3A
When it began flying in mid-1961, Atlas LV-3A Agena B
was the heaviest, most-capable rocket the United States had launched up to that time. The
stretched Agena had, for the first time, a restartable engine. LV-3A Agena B worked for
both the U.S. Air Force and NASA from the outset, launching MIDAS and SAMOS from
Vandenberg and Ranger and Mariner from Cape Canaveral for a 28 launch total. SAMOS turned
into a frustrating program failure. MIDAS did better, though with many early setbacks,
setting the stage for later missile warning satellites. Both used Agena as a spacecraft
bus. Ranger failed stubbornly for two years until No. 7 finally photographed the Moon
before impact in mid-1964. Mariner 2 was a major early success. Agena B restarted
successfully to send the little JPL satellite toward mankind's first successful flyby of
another planet (Venus) in 1962.
7. Atlas LV-3C
LV-3C/Centaur was the original "Atlas Centaur"
with the world's first liquid hydrogen fueled orbital stage. Twelve were launched between
1962 and 1967, during a tortuous development program. The first launch failed on May 8,
1962 when Centaur's insulation panels failed during the first minute of flight. Four more
failures would follow (a total of three orbit fails and two RL10 restart fails). One of
them, AC-5, ended in the biggest on-pad explosion yet seen in Florida. The first real
payload, Surveyor 1, wasn't launched until May 30, 1966 by AC-10 (the 8th flight).
Surveyors 2-4 followed before the more capable SLV 3C/Centaur D vehicle took over.
The program was saved (after a Congressional investigation) by wresting it from MSFC and
placing it in the hands of Lewis Center's Abe Silverstein. Program development costs
increased by nearly a factor of six from original plans. In hindsight, with Centaur still
serving the nation, it was worth every penny.
There were four insulation panels that separated using "flexible, linear, shaped
charges" along their "forward, aft, and longitudinal seams".
Hinge arms at the bottom of the panels caused them to rotate away from the vehicle. A
helium purge between the tank wall and the insulation panel used ground source helium that
ended at liftoff, requiring careful venting during the flight. Jettisoning the
insulation shed 552 kg of dry mass from the stage on the way up, adding hundreds of kg of
8. Atlas NIKE
In 1962, Atlas D began its first non-ICBM suborbital
mission - launching targets for Nike Zeus ABM test intercepts. Nike launches from
Kwajalein attempted to "intercept" the RVs upon reentry (a few hundred meters
distance counted because operational Nike would use nuclear warheads for ABM intercepts).
The program effort was remarkably robust compared to today's infrequent test attempts for
the current ABM system.
The RVs looked vaguely similar to Avco RVs that ended up on Minuteman missiles. There were
16 launches, including one by an Atlas E, during the initial "Nike Target Missile (or
Measurements) Program". Some were only launched to be tracked by the Nike radar
systems. Four were Atlas failures. Some saw the Nike aim for the disintegrating Atlas tank
rather than the RV. One intercepted a decoy rather than the RV. Four were outright
successful "intercepts" of the RV itself. A variety of RVs were used, and decoys
were part of the mix.
Nike Zeus was cancelled in favor of Nike-X, and 20 more Atlas launches were performed
during 1964-66 as part of the "Nike-X Reentry Measurements Program". These
featured a new cylindrical section named "HIRS" that housed a pair of retro
rockets to push Atlas further away from the RV after separation. HIRS was also used
by ABRES. Many were launched only to be tracked. Others may have been intercept attempts,
but information is vague. Four were Atlas failures. A variety of RV types appear to have
flown. Two examples are shown.
9. Atlas ABRES
ABRES (Advanced Ballistic Reentry Systems) was a long
running program that encompassed about 70 Atlas launches. These were used to develop new
ICBM reentry vehicles and decoys, and to continue ABM testing, including tracking system
testing. Launches began from Cape Canaveral, but soon settled on the Vandenberg AFB 576 A
and B complexes, which included six launch pads. During the mid 1960s these were among the
busiest launch pads in the U.S.. The program was substantial. Most launches aimed toward
Kwajalein, but a few went toward Johnston or Wake Islands.
The Narwhal-like SBGRV vehicles were distinctive, topped by long, 2,000 pound RVs built by
Douglas that used flaps and gas jets to maneuver. Ford-Philco developed the Trident
post-boost bus, which used dual-thrust solid motors, to launch numerous RMP-B (Reentry
Measurements Program) missions and which apparently tested MIRV techniques. HIRS was used
on some missions. Maneuverable RVs were tested. Some of this stuff is still cloaked in
mystery, since it developed pointy-nosed, stealthy RVs for Minuteman and Trident and other
10. Atlas LV-3A
Atlas LV-3A/Agena D flew 15 times during 1963 to 1965,
before being supplanted by the standardized Atlas SLV-3. Agena D was a first step in
that standardization, since it was designed to fly on Thor, Atlas, and Titan. Atlas Agena
D was developed primarily to orbit NRO's Gambit-1 from Vandenberg AFB. Ten of the 15
LV-3A/Agena D flights did exactly that. Gambit-1 was the first seriously impressive U.S.
imaging spysat. It likely cost more than NASA's Gemini program.
LV-3A/Agena D also launched three pairs Vela satellites from Cape Canaveral LC 13 into
deep orbits beyond the GEO belt, where they monitored for signs of nuclear explosions
following the signing of the nuclear limited test ban treaty.
Public awareness of LV-3A/Agena D was limited to the Mariner 3 and Mariner 4 launches in
November, 1964. Both JPL spacecraft were processed simultaneously. Mariner 3 flew from LC
13 and Mariner 4 from LC 12. Both made it to solar orbit, but Mariner 3 died in its
never-ejected shroud. Mariner 4 performed the first successful flyby of Mars, returning
the first close photographs of its surface.
11. Atlas SLV-3
SLV-3 Agena D flew 47 times during 1964-1967. A lone
SLV-3 Agena B flew for NASA in 1966.
Gambit-1 accounted for 28 launches including 2 failures. GATV flew 6 times, suffering two
frustrating launch failures but also scoring the first orbital docking missions with
Gemini. Five highly successful Lunar Orbiters were launched for NASA without a hitch.
Midas/RTS-1 flew three times, advancing missile detection technology despite one ending up
in an unplanned elliptical orbit. Three ATS launches were performed for NASA, with one
falling short of a full GTO due to an Agena failure. Mariner 5 was successfully launched
toward Venus on the final Mariner/Agena flight.
Snapshot is an attention grabber. Launched in March 1964 from Vandenberg AFB PALC 2-4
(today's SLC 4E used by Falcon 9), Snapshot remains the only nuclear reactor ever orbited
by the United States. Its SNAP-10A reactor, loaded with 1.35 kg of U-235 fuel rods, went
critical as planned soon after reaching its 1,300 km x 90 deg orbit. It operated 45 days
before a power system failure caused it to automatically shut down. Years later, the inert
satellite (which includes the attached Agena) began shedding debris. No one knows if
radioactive material is involved, but it is all still up there.
12. Atlas D FIRE
After Project Mercury, and straddling the beginning of
Project Gemini, NASA launched two Atlas D rockets with a mini-Apollo capsule on top within
a shroud to test it at 11,300 m/s reentry velocity. This was Project FIRE (Flight
Investigation of Reentry Environment). Atlas launched the FIRE payload, which included an
Antares IIA solid motor, on a high apogee suborbital trajectory. After coasting past
apogee, the spin-stabilized Antares IIA motor fired to accelerate the 87 kg "Reentry
Package" toward the atmosphere. The successful launches took place from Cape
Canaveral LC 12. The capsules, not designed to be recovered, impacted near the Ascension
Islands some 8,250 km downrange after transmitting a wealth of data.
13. Atlas D/F OV-1
"Orbiting Vehicle satellites were conceived
by the Air Force as a low-cost way to piggyback small satellites onto suborbital ABRES
Atlas flights. They consisted of a Propulsion Module built around an Altair 2 or 3 solid
motor with cold-gas 3-axis control added, topped by a torpedo-like satellite. The vehicle
would be ejected about five minutes after liftoff and coast to apogee before firing its
motor to acheive orbital velocity.
The first two OV-1 attempts in 1965 rode as initially conceived in side-mounted pods. The
first Atlas almost succeeded, but suffered an early sustainer shutdown and the OV-1 1
payload failed to separate. The Avco MTV-1 reentry vehicle apparently failed to meet its
objectives due to the Atlas sustainer issue. The second Atlas, topped by a Mk 3 RV, failed
The program then switched to dedicated Atlas D vehicles with pairs of nose-mounted OV-1
payloads housed in odd hammerhead shark-like fairings. Five launch successes followed,
with eight OV-1 successes and two OV-1 payloads that failed to separate or failed to reach
orbit after separating. One OV-1 was a dummysat. The first three were flown down the
Western Test Range, producing retrograde orbits with 144 deg inclinations. The last two
Atlas D OV-1 missions flew to near-polar orbits, with the final launch in 1967 carrying
two nose-mounted and one side-mounted OV-1 payloads.
OV-1 then moved to Atlas F, where the 84 inch diameter Trident program interstage was used
along with a payload fairing to house up to three vehicles. More powerful Altair 3 motors
were employed. Seventeen total payloads were orbited, including ten that had OV-1
designations. All went to near-polar orbits. It must have been interesting to track these
missions with their multiple motor firings all in close order.
14. Atlas SLV-3B
When it flew from Cape Kennedy's LC 12 in 1966, NASA's
Orbiting Astronomical Observatory (OAO 1) was called "the largest, heaviest and most
electronically complex unmanned spacecraft ever developed by the United States".
The big payload required a 3.048 meter diameter shroud that covered both OAO 1 and
the Agena stage that inserted it into orbit. Thus was born SLV-3B Agena D, an Atlas
configuration that only flew once.
SLV-3B basically married an LV-3C Atlas Centaur first stage with an Agena second stage.
General Dynamics/Convair developed the three-piece shroud, which had a fixed part and two
bisector jettisonable parts. A special interstage adapter was also developed to hold Agena
inside the shroud. The shroud separated after SECO but before VECO. Agena fired first to
reach a roughly 140 x 800 km x 35 deg transfer orbit. It restarted at about T +50 minutes
to put OAO 1 into an 800 km x 35 deg final orbit. (OAO-1 and Agena are both still up there
as of 2015 in those relatively high orbits.)
SLV-3B Agena D worked perfectly, but OAO 1 suffered a massive electrical system failure
after only 20 orbits and was lost. For some reason the launch vehicle, which cost a good
bit of money and time to develop, never flew again.
15. Atlas SLV-3 (ATDA/Prime)
During 1966 and 1967, four SLV-3 series Atlas vehicles
launched with no upper stages. The first carried the Augmented Target Docking Adapter
(ATDA) into a 300 km x 28.9 deg orbit for the Gemini 9A mission, a couple of weeks after
the original Agena-launched target was lost in an Atlas failure. ATDA, a back-up target,
did not have its own propulsion system, only an attitude control system, so Atlas did all
the work and the sustainer stage also reached orbit. The ATDA shroud failed to separate,
creating the famous "Angry Alligator" that still provided useful service as a
rendezvous target for the Gemini 9A crew.
The U.S. Air Force performed three SLV-3 Atlas launches from Vandenberg AFB SLC 3E with
Martin X-23A (SV-5D) PRIME (Precision Reentry Including Maneuvering reEntry) lifting body
re-entry vehicles. These were suborbital flights down the western missile range that
demonstrated cross-range maneuvering by the 405 kg SV-5D vehicles. All three launches and
reentries were successful, but the SV-5D was only able to be recovered on the third and
final flight. A fourth SV-5D and SLV-3 were nearly ready to fly when the program was
stopped due to the earlier successes. You can see the recovered and unflown SV-5D vehicles
at the USAF Dayton museum. The unused Atlas SLV-3 was re-assigned to lift a Burner 2 upper
stage and payload in 1968.
From 1967 through 1972, Atlas SLV-3C Centaur D launched
Surveyors, Mariners, and Pioneers, including the first made made objects to orbit another
planet (Mariner 9) and to leave the solar system (Pioneer 10).
17. Atlas SLV-3A
The workhorse Atlas-Agena (mostly SLV-3/Agena D) flew 25
times in 1966, launching Air Force and NASA payloads from five launch pads at two launch
ranges. The numbers fell to 9 launches from three pads in 1967, as the Air Force dialed
down KH-7. Suddenly, as 1968 began, only Cape Canaveral's LC 13 remained active. On it was
stacked the last standard NASA Atlas-Agena D (there would be one final one-off Atlas
F/Agena D for Seasat in 1978). It was the first stretched SLV-3A Atlas, sometimes called
"Long Tank Atlas", more often called "Improved Atlas for Agena". It
launched OGO-5, then went "black" launching Canyon and Rhyolite/Aquacade
COMINT/ELINT satellites for DoD until 1978 (a total of 12 launch attempts including
OGO-5). Only a few photos of the secret SLV-3A/Agena D vehicles have appeared (only two or
three of the twelve). The Rhyolite/Aquacade Agenas were topped by crazy-long fairings. The
shorter Canyon fairings were shiny gold. Who knows, maybe it was gold!
18. Atlas Burner 2
Atlas was topped by Boeing's Burner 2 stage on two
occasions. The first used the unassigned SLV-3 booster (7004) from the PRIME program to
launch a cluster of 11 or so small Space Test Program satellites from Vandenberg AFB SLC
3E on August 16, 1968. Burner 2 had been developed to fly on retired Thor boosters using a
small conical payload fairing. For this first Atlas flight, however, a very long
cylindrical section was added to the shroud so that it was half as long as the Atlas
itself! Something happened, reported variously as "shroud collapsed" or
"shroud failed to separate" or "Burner 2 failed to start". Likely all
three statements are true. At any rate, the planned near-polar orbit was not achieved.
The failure may have dashed plans for more frequent Atlas Burner 2 missions, because
Boeing's stage, which was essentially a Star 37B solid motor held in a frame that included
its own guidance system with three-axis attitude control and velocity trim via. hydrogen
peroxide thrusters and cold gas RCS, only flew one more time on Atlas. The final flight
used retired Atlas 102F to orbit Radsat and Radcat 2 from the old 576 A1 pad on October 2,
1972. Note that this successful flight used a shorter payload fairing.
SLV-3D Centaur D-1A
Atlas SLV-3D Centaur D-1A(R) was NASA's main-stay medium
lifter during the 1970s and early 1980s. Though dimensionally similar to SLV-3C Centaur D,
it had improved booster thrust (more than 431 Klbf), better sustainer specific impulse,
updated avionics that allowed Centaur to control the entire launch vehicle, a bigger
fairing option, tweaked Centaur thrust (up to 33 Klbf for AC-54 and later) and other
refinements made during the vehicle's production run that steadily improved performance.
GTO capability, for example increased from 1,860 kg (AC-30) to about 2,000 kg (AC-61).
SLV-3D launched Pioneers 11-13, Mariner 10, and three HEAO satellites for NASA. It orbited
fleets of GEO comsats for the U.S. Navy, for Intelsat, and for Comstar. There were three
launch failures in this rocket's 32 flights. FLTSATCOM 5, one of the failure, reached its
planned orbit but its UHF antennas were damaged by the delamination of the inner lining of
the shroud. The satellite was nursed to near-GEO and its solar arrays were
deployed, but its antennas would not deploy.
20. Atlas E/F GPS
Numerous retired Atlas E and F missiles were repurposed
and flown to orbit. Most were serially refurbished at Vandenberg AFB in the Vandenberg
Atlas Modification Program (VAMP). The majority were topped by solid motor stages. From
1974, all flew from Vandenberg AFB SLC 3E or 3W.
Thirteen Atlas E/F flights carried early developmental GPS satellites. An 84 inch diameter
fairing, derived from the Atlas/Trident shroud, was used to house the top few inches of
the tapered Atlas LOX tank, one or two solid motors, and the payload. Atlas flew
suborbital, then the spin-stabilized solid motors fired to boost the payload into an
elliptical transfer orbit. An apogee kick motor assigned to the payload circularized the
The Payload Transfer System (PTS) used a single Star 37E to orbit Navigation Test
Satellite 1 in 1974. It served as a prototype for Space Guidance System 1, which used two
Star 37E motors fired sequentially to launch NTS-2 in 1977, and GPS 1-7 subsequently.
Fairchild was the PTS and SGS-1 contractor. All launches succeeded until the final SGS-1
launch with GPS 7 in 1981. An improperly refurbished booster engine failed at T+6 seconds
and Atlas crashed only 500 feet from SLC 3E.
McDonnell Douglas created SGS-2, which used two stacked Star 48B motors to launch GPS 8-11
The re-purposed Atlas missiles provided a cost-effective, and generally successful, launch
service for the first generation GPS satellites.
21. Atlas E/F
Retired Atlas E/F ICBMs flew once each with Star 17A and
Star 20 solid motor upper stages, and twice with Star 27 upper stages that were integrated
with 3-axis control by Fairchild as "Orbital Insertion Stage(s)" (OIS).
Atlas 71F carried the Star 17A on the STP P72-2 mission on April 13, 1975 from SLC 3W. It
used a 65 inch diameter fairing, within which rode a Rockwell-built RM-20 satellite. In
those days, RP-1 and LOX were ducted into the flame trench during the countdown. This
time, the propellants pooled and exploded when the Atlas engines ignited, damaging the
propulsion system. Still, Atlas lifted off and headed downrange. Eventually, the damaged
engines shut down and at T+303 seconds Range Safety pushed the button.
Atlas 27F/OIS boosted the 850 kg Solwind satellite into a nearly 600 km x 97.8 deg orbit
from SLC 3W on February 24, 1979. Atlas 41E /OIS lofted 635 kg Geosat into a 775 km x 108
deg orbit from the same pad on March 13, 1985. Geosat was classified for NRL, then it
performed a declassified mission, then, gradually, more and more of the classified mapping
data was released.
Atlas 28E with a Star 20 (Altair 3A) motor orbited three "Stacksats" and a
"Prototype Deployment Device" on the STP P87-2 mission from SLC 3W on April 11,
1990. A 745 x 627 km x 89.8 deg orbit was achieved. The Stacksats and the Star 20 were
originally designed for Scout launches.
22. Atlas E/F MSD
Atlas E/F, topped by the Multiple Satellite Dispenser
(MSD), carried Parcae (Naval Ocean Surveillance System) triplets into 1,100 km x 63 deg
orbits beginning in 1976. Parcae were SIGINT/ELINT satellites for the U.S. Navy that were
used to track the then-expanding Soviet navy. They flew in "formation" to allow
use of the radio signal time difference of arrival method.
MSD was built around an FW-4D solid motor, previously used as a Scout fourth stage and a
Delta third stage. It was fitted with an MMH monopropellant trim system. The FW-4D was
spin-stabilized during its apogee kick burn.
The first three launches using Atlas F stages were successful. The final launch, using
Atlas 68E, failed on December 9, 1980 when one of the booster engines shut down just
before its planned cutoff, putting Atlas into a spin. The sustainer engine fired, but in
the wrong direction and it all ended in a high altitude explosion several minutes after
liftoff. The Soviet Navy gained a reprieve, briefly.
23. Atlas 23F
One-of-a-kind Atlas F Agena D boosted Seasat into
near-polar orbit from VAFB SLC 3W on June 27, 1978. For this NASA/JPL mission, which
required a wider payload fairing, General Dynamics modified Atlas 23F (originally
manufactured in 1961 for ICBM duty), cutting off its tapered LOX tank section and
replacing it with a cylindrical section. GD also provided a modified interstage from its
Atlas-Centaur program. Lockheed provided the payload fairing, which was a modified
leftover ground test article from its Titan 3B/Ascent Agena program. Agena D fired
twice to reach a 780 x 790 km x 108.022 deg orbit, then served as a bus for the innovative
synthetic aperture radar imaging satellite. Seasat mapped sea states before suffering an
electrical failure 106 days into its mission.
This scrounged-up oddball rocket, which worked to perfection, was the final Atlas-Agena.
24. Atlas E/F ISS
Here's Atlas E/F with a Star 37S upper stage. The
Star motor was integrated with the satellite so that it could provide coast and roll
control. Atlas itself flew suborbital. Star 37S ignited after a five minute
coast to apogee to complete the orbital insertion. These put NOAA and DMSP-5D2
weather satellites into sun synchronous orbit from Vandenberg AFB from 1978 until 1995.
The last one was the final refurbished ex-Atlas ICBM to fly.
25. Atlas H
Atlas H (which started flying one year before Atlas
G/Centaur) was developed to orbit more Parcae (White Cloud or NOSS) triplets during the
1980s. It used an SLV-3D first stage, with an MSD solid motor upper stage replacing
Centaur. An Atlas E/F "GERTS" autopilot and radio-inertial guidance system was
added to the first stage, as was a vernier solo phase capability and a 10 foot to 7 foot
tapered adapter. The MA-5 propulsion system continued to see improved thrust and specific
impulse. Atlas H flew five times from Vandenberg AFB SLC 3E during the 1983-87 period. The
rocket may have been created as an interim solution while waiting for West Coast STS.
26. Atlas G Centaur D-1AR ("Atlas 1")
Atlas G Centaur and its similar cousin Atlas 1 flew 18
times between 1984 and 1997. Five of those flights failed and another was damaged during
launch processing, possibly symptomatic of the stop-start nature of the program during
that era. Subsequent Atlas success sprung from this difficult era, when Atlas production
was shutting down in favor of Shuttle.
Atlas G featured an 81 inch Atlas stretch compared to SLV-3D. It's MA-5 propulsion system
was up-thrusted once more to produce nearly 440,000 pounds of thrust at liftoff (with an
ISP up-tick to boot). Centaur's boost pumps were eliminated and its thrusters and RL-10
engines were improved.
The rocket, still under NASA Lewis Center purview, was developed primarily to boost 2,313
kg FLTSATCOM 5A to GTO. Only the Cape's LC 39B was modified to handle the taller rocket
while LC 39A was assigned to the Shuttle-Centaur program.
AC-62, the first to fly in 1984, failed when the Centaur LOX tank was punctured by the
stage separation system. Subsequent launches were successful until AC-67 was astonishingly
knocked down by lightning in 1987. The AC-68 Centaur stage was "deflated" during
launch processing, requiring construction of a new stage for "AC-68R", which
finally orbited FLTSATCOM 5A 8 on September 25, 1989, ending NASA oversight.
By then, after Challenger, Atlas Centaur production had resumed. "Atlas 1" was
programmed as a commercial launch service. It was essentially an Atlas G Centaur D-1AR
with an improved guidance system and a 165 inch diameter metal payload fairing option.
AC-69 through AC-79 flew during the 1990-97 period, orbiting commercial, NASA, and USN
payloads. AC-70 and 71 suffered RL-10 failures and AC-74 suffered a rare MA-5 sustainer
failure. The Atlas 2 series with all of its improvements flew concurrently with Atlas 1
for seven years. AC-79 was the last Atlas with vernier engines and the last Centaur with
jettisonable insulation panels.
27. Atlas 2/2A(S)
General Dynamics won the USAF MLV-2 competition in 1988.
The company developed the Atlas 2 series for MLV-2. After years of underinvestment, Atlas
and Centaur were finally able to be upgraded. Atlas was stretched 9 feet and Centaur by 3
feet. Centaur gained fixed foam insulation. Guidance system improvements were made. Atlas
gained an upgraded MA-5A propulsion system that produced nearly 480 Klb liftoff thrust.
The old Atlas verniers were removed, replaced by a new hydrazine roll control system on
the interstage. Atlas 2 still used two RL10A-3-3A engines, but Atlas 2A used higher
thrust, higher ISP RL10A-4 engines with extendible nozzles. Atlas 2AS added four Thiokol
Castor 4A solid rocket boosters, two ground-lit and two air-lit.
Cape Canaveral's dormant LC 36A was returned to launch service, alongside still-active
36B, and Vandenberg AFB SLC 3E was completely rebuilt for the first West Coast Atlas
Centaurs (Atlas 2AS beginning in 1999).
Ten Atlas 2, 23 Atlas 2A, and 30 Atlas 2AS launches took place with no failures during
Meanwhile, the Cold War ended. Martin Marietta merged GD in 1993, then Lockheed Martin
took over in 1995. GD's long-running Atlas production line was shut down and moved to
Waterton Canyon, Colorado sometime during 1995-96 or so. Kearny Mesa rolled out its last
Atlas - AC-126 - on September 27, 1995 and was subsequently razed, the land sold off.
For many that seemed to be the end of the real Atlas program, but Atlas would
flourish yet under Lockheed Martin's management. AC-122, which flew two months after
AC-126 during April 1996, was the first Atlas assembled at Waterton.
28. Atlas 3 A/B
After Martin Marietta merged General Dynamics in 1993,
the company took a fresh look at Atlas. Atlas 2AR, announced after Lockheed merged
Martin Marietta in 1995, was the resulting plan. It would greatly simplify the launch
vehicle, replacing the stage-and-a-half concept with a "Single-
Stage Atlas" with a powerful new propulsion system that would allow removal of one of
the two Centaur engines and lift more than 4 metric tons to GTO. Candidate first stage
engines included RD-180, two NK-33, and a pair of proposed "RS-X" Rocketdyne
engines. Rocketdyne, focused on RS-68 development, dropped out of the competition in
September, 1995. RD-180 won the job in Janaury 1996 and it became apparent that Lockheed
Martin expected the new rocket to serve as a "risk mitigator" for its proposed
EELV design, which was one of four competing designs selected in 1995 for the final round.
Sometime after 1996, "Atlas 2AR" was renamed "Atlas 3A" and follow-on
"Atlas 2ARC" became "Atlas 3B". The Atlas stage was the same for both.
Atlas 3A used a Centaur with the same dimensions as the Atlas 2/2A Centaur, while Atlas 3B
introduced the stretched "Common Centaur" that still
essentially flies today atop Atlas 5. Early plans for an "Atlas 2ARS" with two
Castor strap-on motors were dropped.
In early 1998, an integrated stage hot firing of an RD-180 attached to an Atlas 3 test
thrust structure took place at Marshall Space Flight Center. This was the highest thrust
engine tested at MSFC since F-1 during the 1960s.
Launch Complex 36B was modified to support all Atlas 3A/B launches. In the end, there
would only be six, all successful. Atlas 3A was ready to fly in 1999, but payload issues
pushed its inaugural "AC-201" launch back to May 24, 2000, when it orbited
Eutelsat W4. AC-204, the first Atlas 3B (this one with a Dual Engine Centaur) flew next,
with Echostar 7 on February 21, 2002. Atlas 5 would fly before any more Atlas 3 flights
took place. As a result, Atlas 3 was soon phased out, with a final launch in 2005 by
AC-206 with two Intruder satellites. AC-206 was the final launch from historic LC 36. The
entire two-pad complex was leveled to bare earth not long after.