Delta 2 Productive Years
Fourteenth in a Series Reviewing Thor Family History
by Ed Kyle, Updated 02/12/2017
Delta 261, a "Med Lite" Delta, Launches NASA's Deep
Space One from Cape Canaveral in 1998
From 1989 through 2011, Delta 2 was the most often-flown,
versatile, productive, and reliable U.S. launch vehicle. Delta 2 returned the Thor
family to three launch pads at two launch sites, and it became common to see multiple
Deltas stacked simultaneously on those pads. 151 Delta 2 rockets would fly by the
end of 2011, and 149 would succeed, making it one of the most successful orbital launchers
Born to launch GPS satellites for the U.S. Air Force - it would
orbit 48 in 49 attempts over the years - Delta 2 steadily expanded its
"customer" base to include commercial satellites, non-U.S. government missions,
and NASA satellites. For NASA, Delta 2 eventually performed missions that no
previous Delta or Thor had performed - flights far beyond Earth orbit into deep space and
Delta 2's 23 year run made it the longest-lived essentially
unchanged U.S. launch vehicle model. Incremental upgrades occurred during that time,
but the basic propulsion and structure remained little changed. Delta 2 ownership
changed hands twice during its life, and its production and engineering sites moved twice,
but its culture of success somehow remained unchanged.
Delta 210, one of the Final Castor 4A Boosted Extra Extended
Long Tank Deltas, with a 10 Foot Diameter Metal Fairing
Delta 210, a 6920-10 with no third stage, returned Delta to NASA
service after a three year hiatus by orbiting EUVE (Extreme UltraViolet Explorer) from Pad
17A on June 7, 1992. The 3.275 tonne satellite, originally designed to be launched
aboard Shuttle, entered a roughly 500 km x 28.4 deg orbit. This was part of NASA's
Medium Expendable Launch Vehicle Services (MELVS) contract with McDonnell Douglas for
Delta 2 launch services.
Delta 212 was a landmark because it was the final 6925, the last
Delta with Castor 4A strap on motors, or Thiokol Castor motors of any type - a
relationship that began in 1964. It launched Geotail, a 1,009 kg spinner built by
Japan's ISAS designed to measure "fundamental magnetospheric processes", from LC
17A on July 24, 1992. Geotail was boosted into a highly elliptical orbit, which was
subsequently modified through the use of two lunar swingbys. Geotail was still
acquiring data as of 2005.
Delta 2 Model Comparison
After the final 6900 series rockets flew, Delta 7925, a 7000 core
with an RS-27A engine boosted by nine GEM-40 Hercules Graphite Epoxy Motors topped by an
Aerojet AJ10-118K ITIP (Improved Transtage Injector Program) powered second stage and a
Star 48B spinning solid motor third stage, became the most common model. 7925
would fly 69 times by the end of 2011. It was most often used to orbit GPS-2A, 2R,
and 2RM satellites, Delta 2's most common payload. Delta 7925 also launched
communication and scientific satellites.
For GPS missions, Delta's pressure-fed hypergolic propellant
second stage coasted in a parking orbit before restarting near the first (descending) or
second (ascending) equator crossing. The burn was followed by spin up and separation
of the Star 48B third stage, which began its burn only a few minutes later. The GPS
satellite would then separate into a transfer orbit with a roughly 200 km perigee and
20,370 km apogee, and usually with a 40 deg inclination. GPS 2A satellites weighed
1.816 tonnes at separation. Upon reaching first apogee, the satellite would fire its
own kick motor to circularize its orbit at roughly 20,200 km and to increase its
inclination to 55 deg. The GPS constellation steadily grew to and beyond its planned
four satellites in each of six orbital planes.
Delta 226, a Standard 7925 GPS-Hauler with a
9.5 Foot Fairing
Delta 7925 orbited 15 GPS 2A
satellites by the end of 1994. It also performed nine geosynchronous transfer orbit
(GTO) or highly elliptical orbit missions during the same period. NATO 4A, ASC 2,
and Satcom C5 were boosted to GTO by 7925 rockets during 1991. Indonesia's
Palapa B4, Satcom C4, and Germany's DFS Kopernikus 3 were likewise orbited in 1992.
GTO missions progressed in a similar fashion to GPS flights, except that the transfer
orbit apogee was typically around 36,000 km or higher and the inclination was usually in
the 20-28 degree range. GTO perigees might be as low as 185 km but sometimes
exceeded 1,000 km depending on the weight of the satellite, which typically ranged between
1.1 and 1.5 tonnes.
One slightly thrilling moment occurred
on November 6, 1992, when Delta 216 on Pad 17A with GPS 2A-7 reached the ignition point in
the count, ignited its verniers, and shut down before igniting its main engine and solids.
A detector wire mounted at a vernier nozzle failed to burn through as designed,
causing the shut down. The abort pushed the launch back to November 22. The
resulting launch was the first of eight consecutive, successfully monotonous 7925 GPS
flights that spanned the following 11 months.
The GPS mission pattern was finally
Delta 224, yet another 7925, which boosted UK-built NATO 4B into GTO from Cape
Canaveral LC 17A on December 8, 1993.
There were only three Delta 2 launches
in 1994, making it the slowest year for Delta since 1988. Much of the initial Block
2 GPS constellation had reached orbit by then. All three were 7925 models, but all
used different payload fairings.
225 Suffered a Last Second Abort
Delta 225, with an 8 foot diameter
fairing, carried Galaxy 1R2, a 1,397 kg Hughes 376 spinner, into GTO from LC 17B on
February 19, 1994. The launch occurred nine days after an on-pad abort that saw the
first stage verniers start, then shut down. The problem was traced to circuitry that
monitored vernier combustion chamber pressure.
Delta 226, with the standard Delta 2 9.5 foot diameter fairing, orbited Navstar GPS 2A-15
from LC 17A on March 10. The Small Expendable Deployer System (SEDS-2), a space
tether experiment, was also deployed from Delta's second stage. Ground observers
could spot the 19 km long SEDS-2 tether (which broke away from the stage after several
days) for weeks until it reentered.
Delta 227, using a 10 foot diameter fairing, launched NASA's 1,250 kg WIND from LC 17B on
November 1 toward an eventual Earth-Sun L1-point halo orbit (via. several lunar swingbys)
to measure solar winds. This was the 41st consecutive Delta 2 success and 49th
consecutive Delta success, a new record for the launch vehicle that dated back to 1986.
Delta 228 Liftoff
Nine months passed before the next
Delta launch. It was Delta 228, a 7925 that faltered during its flight with Koreasat
1 from LC 17B on August 5, 1995. One of the three air-started solid motors failed to
jettison, resulting in 1,464 kg Koreasat 1 being deposited in an orbit that was about
5,000 km short of its planned GTO apogee. The satellite, a Lockheed Martin AS-3000
series 3-axis stabilized craft, had to use up 6 years worth of on-orbit propellant to make
up the 325 m/sec delta-v deficiency, shortening Koreasat 1's life to about 4.5 years.
In the end, the satellite managed to function until December 2005, likely the
result of extra-careful propellant management.
The failure was attributed to an explosive transfer line (a type of detonation cord)
possibly having been exposed to high temperatures. This would have been caused by a
failure of insulation protecting the rocket's booster separation circuits. After 49
consecutive successes, it was the first Delta failure since 1986 and the first Delta 2
failure after 41 successes. Delta would continue to carry 49 success stars on its
decal until the mid-2000s.
West Coast Return
Delta 229 Returned Delta to
Three months after the Delta 228
failure, Delta 229, a 7920-10, successfully launched Radarsat 1 and Surfsat 1 into near
polar orbits from Vandenberg AFB Space Launch Complex 2 West on November 4, 1995.
This first launch from SLC 2W since Delta 189 orbited COBE in 1989 followed a
reconstruction of the pad for Delta 2. It was also the first flight of a Delta 7920,
the version without a Star 48B third stage. 7920 was typically used for LEO
missions, usually from Vandenberg into near polar orbit, and would become the second most
common Delta 2 model.
Radarsat 1 was a 2,750 kg C-Band Synthetic Aperture Radar mapper largely built by Ball
Aerospace for prime contractor Spar Aerospace for the Canadian Space Agency. It was
Canada's first remote-sensing satellite. The big-antenna satellite was inserted into
an 832 km x 98.6 deg sun synchronous orbit.
Surfsat 1 was the "Summer Undergraduate Research Fellowship Satellite", built by
Caltech students with JPL involvement. It consisted of two metal boxes bolted to
Delta's second stage covered in solar cells to produce 15 Watts of power, filled with
X-band, Ku-band, and Ka-band transponders, and fitted with omni directional antennas to
test new NASA ground tracking systems. The Delta second stage boosted itself and 55
kg Surfsat 1 into a 935 x 1495 km x 100.6 deg orbit after Radarsat 1 separated. The
stage and Surfsat were gravity gradient stabilized and there were no batteries. The
entire experiment cost $3 million.
Delta 230, another 7920-10, flew from
Cape Canaveral LC 17A on December 30, 1995 with NASA's XTE (X-Ray Timing Explorer).
XTE, a 3,035 kg X-ray telescope (essentially), was boosted into a 565 x 585 km x 23 deg
orbit where it scanned the cosmos until being decommissioned on January 5, 2012. It
is expected to reenter sometime during the next decade.
Delta 230 was the first Delta controlled by a Redundant Inertial Flight Control Assembly
(RIFCA). RIFCA, built around six ring laser gyroscopes and six accelerometers,
provided triple redundant guidance, flight control and mission sequencing functions.
Developed by AlliedSignal of New Jersey, RIFCA replaced the previous DRIMS guidance
and control system that had been used since 1978.
Delta 232 Launched Asteroid
Explorer NEAR in 1996
As 1995 ended, Delta's McDonnell
Douglas team stood on the cusp of a real golden age - four years of launch-a-month
business that would solidify the rocket's oft-used "workhorse" label.
Delta 2 would liftoff 43 times during the four year 1996-1999 period. There would be
more GPS launches, but also many "Little-LEO" launches and renewed NASA work as
the Agency entered its "Better, Cheaper, Faster" era. For the first time,
the ancestor of the old Douglas Thunder God would head for Mars.
Delta 2 flew ten times in 1996.
The first, Delta 231 (a 7925) boosted Koreasat 2 into GTO from Canaveral's LC 27B on
January 14, 1996. This was a successful repeat of the faulty Koreasat 1 mission.
Delta 232, a 7925-8 with an increasingly rare eight foot diameter fairing, boosted NASA's
Near Earth Asteroid Rendezvous (NEAR) spacecraft into solar orbit from the same pad just
over one month later, on February 17, 1996. (Pad A was not used for launches for
about six months during this period for restoration work.) This was the first
"Discovery Program" launch. NEAR flew within 750 miles of asteroid 253
Mathilde on June 27, 1997, then topped that by entering orbit around asteroid Eros on
February 14, 2000. Then, on February 12, 2001, NEAR gently landed on Eros,
snapping pictures down to the surface. NEAR achieved several "firsts",
including the first "orbiting and landing on a small, irregular body" and the
"first use of the Internet for communicating with the public through Project
Scientist Andy Chengs regular Science Updates". NEAR really was a
Delta 233, a 7925-10, launched NASA's Polar satellite from Vandenberg AFB SLC 2W on
February 24, 1996. Polar entered a highly elliptical polar orbit from which it
studied the magnetosphere for more than a decade.
Delta 235 on a Rare Sunny Day at Vandenberg's SLC 2W
Delta 234 orbited GPS-2A-16 from Cape Canaveral LC 17B
on March 27, 1996. Deltas 237 and 238 orbited GPS 2A-17 and GPS 2A-18 from Cape
Canaveral LC 17A on July 16 and September 12, 1996, respectfully. These were the
first launches from Pad 17A since its structures had been repainted from red to gray.
Delta 235 was a 7920-10 with a 10 foot diameter
metal fairing. It boosted Ballistic Missile Defense Organization's 2.7 tonne
Midcourse Space Experiment (MSX) into a 900 km sun synchronous orbit from Vandenberg AFB
SLC 2W on April 24, 1996. MSX did missile tracking experiments, then turned its eyes
upward to track GEO satellites until mid-2008.
Delta 236, a 7925, boosted 1.397 tonne Galaxy 9 into GTO from LC 17B on May 23,
1996. Galaxy 9 was the last of the original model Hughes HS-376 spin stabilized
satellites to be launched by a Delta - though a few HS-376HP types would yet fly.
Galaxy 9 was still in use as of 2008. This was the last launch from Pad 17B before
its umbilical and mobile service towers, too, were repainted from red to gray.
On October 7, 1996, the American
Institute of Aeronautics and Astronautics (AIAA) awarded its prestigious George M. Low
Space Transportation Award to the McDonnell Douglas Delta Launch Vehicle Team for their
"unparalleled record of successful launches".
Mars Pathfinder and Star 48B Third
Stage Being Encapsulated by Fairing on Pad 17B.
Delta 239 launched NASA's Mars Global
Surveyor toward Mars from Cape Canaveral LC 17A on November 7, 1996. Delta 240 did
the same for Mars Pathfinder from LC 17B on December 4, 1996. These were NASA Jet
Propulsion Laboratory's (JPL) first "Mars Surveyor" program missions.
Delta 7925 rockets performed both launches. These were essentially straight-up 7925
GPS-style rockets, but used to boost payloads on landmark missions to another
Mars Global Surveyor weighed 1,060 kilograms at launch.
It placed itself into orbit around Mars during September, 1997. Mars
Pathfinder weighed 990 kilograms at launch. It consisted of a small cruise stage
attached to an aeroshell and heat shield that housed parachutes, a folded-up lander
protected by airbags, and a small 10 kilogram rover named "Sojourner". The
contraption deployed its parachute and airbags to "bounce down" onto Mars
surface during July 1997. Several days later, Sojourner drove off of the lander to
begin exploring nearby rocks, capturing public interest as photographs streamed from the
Red Planet to JPL, and then to the Internet, itself still a new public fascination.
Here was NASA's "Faster Better
Cheaper" plan in full-bore action, starting the Agency on a startling decade of
Delta-boosted Martian exploration.
The Big Bang
Delta 241 Astonished Observers
when it Exploded Violently Just Above its Pad
Delta 241, a McDonnell Douglas Delta
2-7925-9.5 lifted off from Cape Canaveral Launch Complex 17A at 16:28 UTC on January 14,
1997, carrying the first 2.03 tonne Block 2R Global Positioning System satellite, commonly
identified as Navstar, or GPS, 2R-1. This was the first Lockheed Martin AS4000
series GPS satellite. The blue and white rocket flew for 12.6 seconds. Then
it exploded less than 500 meters above the pad, shocking launch crews, eyewitnesses, news
reporters, and just about anyone hearing the news. It was probably the biggest
launch vehicle explosion near the ground at the Cape since Atlas Centaur AC-5 nearly 32
Delta 241 had nine GEM strap-on solid rocket motors, six ground start and three air-start,
augmenting an RS-27A powered Extra Long Extended Tank (XLET) first stage. The rocket
was topped by a pressure fed, AJ-10-118K powered second stage and a Star 48B
spin-stablized third stage. Serial numbers were 20055 for the first stage, 20147 for
the second stage, 20050 for the third stage, and 20381-20388 for the GEMs.
About 7.2 seconds after ignition, the casing of GEM No. 2 (Motor K-404) began to split.
The split grew from 28 cm to 100 cm in length within 5.4 seconds, when the motor
"failed catastrophically", triggering the first stage automatic destruct system
at T+12.581 seconds, which created the dramatic fireball less than 500 meters above the
pad. This occurred about 40 milliseconds after SRM No. 2 and No. 8 began to
explode. The upper stages and payload remained intact, drifting upward until the
Flight Control Officer sent command destruct signals 22.3 seconds after liftoff. The
payload and fairing remained intact until they impacted the ground, causing the satellite
propellants to exploded.
Solid motor fragments, and other debris, rained down on Launch Complex 17, trapping the 73
person launch crew for more than an hour in the blockhouse. Conditions in the
blockhouse deteriorated when smoke began entering via. a cable duct, but no one was
injured or killed. About two dozen vehicles in the LC 17 parking lot were
destroyed. It would be the final Delta launch controlled from the Launch Complex
The exact trigger for the Automatic Destruct System was not determined. It may have
been a lanyard pulled due to engine section (boat tail) deformation. It may have
been sympathetic detonation due either to the shock or to high temperatures created by the
The ADS did several things. It fired linear shaped destruct charges that cut open
the sides of the first stage LOX and RP tanks and that simultaneously opened up each SRM -
except for SRMs 2 and 8 which broke away prior to ADS detonation. The ADS also fired
frangible nuts to separate the SRMs (except for SRMs 2 and 8 ).
in LC 17 Parking Lot
The launch vehicle broke up into about
2,100 fragments and more then 2,000 "firebrands" from the SRMs. Debris
landed on and around LC17, LC18, and LC26 (the Space Museum). Damage included 26
destroyed vehicles (including a tractor trailer), 46 damaged vehicles, four destroyed
modular trailers, seven damaged modular trailers, and damage to the Titan 1 and Thor IRBM
displays at the Museum.
An Air Force Accident Investigation Board determined that the motors outer composite
layers had been damaged prior to the launch. The cause of the damage was never
determined, but possible causes included hydrostatic proof testing operations and damage
during launch processing. Significant attention focused on the possibility that a
new ground handling traveling trunnion device might have been involved in the damage.
In the end, the Air Force
investigation report focused most of its attention on the ATK hydrostatic proof test
procedure, which was found to expose some motors to 95% of their ultimate strength
capability. SRM 2's carbon composite case may thus have been damaged slightly, but
not catastrophically, during the test, setting it up for its final failure a few seconds
after its ignition. The investigation recommended improving case strength
design margins, adding ultrasonic inspections, and modifying the hydroproof testing
Alliant manufacturing and test
procedures were altered, ground processing procedures were modified, ultrasonic inspection
steps were added, and no GEM failures subsequently occurred.
Delta 241 served as a kind of harbinger of ugly things to come outside the program.
Five additional Cape Canaveral launch failures would occur during the next 2.5 years, but
none of those failures were by Delta 2 rockets. Delta 2, in fact, was about to
embark on the longest success streak by any U.S. rocket - 96 launches spanning 13 years.
Little LEO Era
First Iridium Launch
With the Delta 241 investigation
complete, McDonnell Douglas returned Delta 2 to service less than four months after the
failure on May 5, 1997, when Delta 242 launched the very first Iridium mission (Iridium
MS-1) from Vandenberg AFB SLC 2W. A Delta 7920-10C, equipped with the first 10 foot
diameter composite payload fairing, lifted five 689 kilogram Iridium satellites into 667
km × 667 km, 86.4° insertion orbits. It was the first of ten successful Delta 2
launches before year's end.
The Delta 242/Iridium MS-1 mission was
a near miss, because the rocket's second stage cold gas attitude control system ran out of
nitrogen gas after the fourth satellite was released but before the fifth was released.
The stage was just entering a slow tumble when the fifth and final satellite
separated. The problem prevented the second stage from performing the usual post
Motorola's Iridium plan called for a
constellation of 66 satellites in low earth orbit, called a "Little LEO"
constellation, to route cellular type phone calls. The idea was that it would be
cheaper to orbit satellites than to build 40,000 cell phone towers.
Five more Iridium mission launches
took place in 1997, all from SLC 2W. Some of the launches were only spaced five
weeks apart. This would be the busiest year for SLC 2W.
Delta 243, a 7925, boosted Thor 2 into
GTO from Cape Canaveral Launch Complex 17A on May 24, 1997. Norway's Thor 2 was a
1.4 metric ton Hughes HS-376HP spinner with 15 Ku band direct to home TV transponders.
Only four months earlier structures at this pad had been damaged by the Delta 241
Boeing Takes Over
Delta 245 and 246 bracketed a historic
change in the U.S. aerospace industry.
Delta 245, a 7925, orbited GPS 2R-2 from LC 17A on July 23, 1997. This was the first
successful "2R" series launch, and the first from LC 17A since the Delta 241
explosion. It would be the last Delta rocket adorned with a "McDonnell
Douglas" decal. McDonnell Douglas would soon - on August 4, 1997 - vanish in a
merger with Boeing, it's long time corporate nemesis.
Delta 246 was Boeing's first. It launched five more Iridium satellites (22-26) from
Vandenberg AFB SLC 2W on August 21, 1997. Boeing Launch Services, essentially just a
renamed McDonnell Douglas Space Systems Company at the time, handled the launch service.
This was Delta's "MS-3" mission for Iridium.
Delta 247 on Pad 17A After Service Tower
Delta 247, a 7920-8, launched NASA's
ACE (Advanced Composition Explorer) from Canaveral LC 17A on August 25, 1997. ACE
was a 785 kg spin-stabilized solar observatory built at JHU/APL, which was sent to an L-1
halo orbit. ACE was still out there operating as of 2012, and had enough propellant
to maintain its orbit until 2024. This may have been the first Delta to carry an
"in memory of" decal, a practice that appears to have begun during the post
McDonnell Douglas era.
Delta 249 launched Navstar 2A-19, the
last 2A model built by Rockwell, from Cape Canaveral LC 17A on November 6, 1997.
1998 would be the busiest ever year
for Delta 2, with 12 launches, all successful. (There was also one unsuccessful
Delta 3 launch.) Four of the launches would be performed by a new
"Med-Lite" Delta 2 variant.
Delta 252, a 7925, started the year on January 9 by boosting Britain's Skynet 4D into GTO
from Cape Canaveral Launch Complex 17B. This was the first launch from "B"
in more than a year, and you could see the effects of the modifications made to the pad
during that time, when it was rebuilt to handle Delta 3 and its bigger GEM-46 solids.
Louvers at the top of the new box-style flame duct forced exhaust upward so that it
wrapped around the rocket. Pad "A" was never modified this way, so a post
modification "B" launches can be identified in photographs by the smoke wrap.
Skynet 4D was a 1.5 tonne 3-axis British Aerospace built satellite with a Star 30E apogee
kick motor. It was the last Skynet launched by a U.S. launch vehicle.
Med-Lite and "Delta Lite"
Comparison of Delta 2 7325 and
Delta 253, the first 7420-10C with
only four strap-on solid motors, launched from LC 17A on February 14, 1998 with the first
four Globalstar satellites. These 450 kg SS/Loral LS-400 satellites were inserted
into 1,400 km x 52 deg orbits. A second Globalstar launch with four more satellites
took place from the same pad on April 24.
Delta 261, a 7326 with only three
strap on motors and with a smaller, Star 37FM third stage. It launched NASA's Deep
Space 1 and SEDSat from Cape Canaveral's just-renamed "Space Launch Complex" 17A
on October 10, 1998. It was the first Delta with only three strap on motors since
1974. Deep Space 1 was a New Millennium technology demonstration mission
that flew a xenon gas ion engine into heliocentric orbit. It weighed 486.3 kg at
launch. DS-1 flew by Asteroid 9962 Braille in July 1999 and comet 19P/Borrelly in
September 2001. SEDSat was a microsatellite that deployed from Delta's second stage,
after DS-1/Star 30FM separated and the stage performed a depletion burn, into a 547 ×
1,079 km x 31.4° orbit.
Delta 264, a 7425 model with only four
strap on motors but with the standard Star 48B third stage, launched NASA's ill-fated 338
kg Mars Climate Orbiter from SLC 17A on December 11, 1998. MCO failed at Mars due to
a targeting error that plunged it destructively through the upper Martian atmosphere just
before it was to fire its main engine to enter orbit. The error was caused by
contractor software programmed to use non-metric units rather than the metric units
specified by NASA-JPL.
Delta 253, the First 7420
These were the first
"Med-Lite" type Delta 2 rockets. The type was originally offered by
McDonnell Douglas in response to NASA's December 1994 request for bids for a Medium Light
Expendable Launch Vehicle Services (Med-Lite) contract. The goal was to create a
rocket that could lift about half as much to orbit as a standard Delta 2, preferably for
half as much money.
A 7320/7326 series Delta could lift
2.8 tonnes to LEO or 0.629 tonnes to escape velocity. A Delta 7420/25 could handle
3.2 tonnes to LEO or 0.806 tonnes to escape. This compared with 5.1 tonnes and 1.284
tonnes, respectfully, for Delta 7920/25.
McDonnell Douglas and Orbital Sciences
teamed to win the contract in March 1995. Orbital's Taurus would handle the lightest
payloads (up to 1.5 tonnes to LEO) in the class while Delta 2 rockets with three or four
strap on motors would handle the heaviest. For "in-between" payloads,
McDonnell Douglas proposed development of a new "Delta-Lite" variant.
Delta Lite would have consisted of two
Castor 120 motors stacked as Stage 1 and 2, topped by an Aerojet AJ10-118K powered Delta 2
ITIP stage and payload fairing. A standard RIFCA would have controlled the rocket's
flight. It would have lifted 1.985 tonnes to LEO, 1.51 tonnes to polar LEO, or 0.66
tonnes to GTO. A growth version with two Castor 4B motors strapped to the first
stage would have lifted 2.61 tonnes, 2.03 tonnes, or 0.86 tonnes to the same orbits -
almost as much as a Delta 7320/26 series "Med Lite" Delta.
NASA's FUSE satellite was slated to be
the first to ride the new rocket in 1998, but after almost a year of negotiation with
NASA, McDonnell Douglas decided not to develop Delta Lite. It determined that NASA
was not offering sufficient payloads in the class to makes its development
worthwhile. Payloads that might have flown on Delta Lite ended up flying on Delta
7300 series rockets instead.
In the end, "Med-Lite" saved
NASA money, but not as much as it had originally hoped.
Delta Model Numbering System
Table 1 lists the Delta model number designations used prior to
and during the Extra Extended Long Tank era.
Table 1: Delta Model Numbers
First Digit: First Stage and Strap on Motor
0: Long Tank, MB-3-3 engine, Castor 2 motors (1968)
1: Extended Long Tank, MB-3-3 engine, Castor 2 motors (1972)
2: Extended Long Tank, RS-27 engine, Castor 2 motors (1974)
3: Extended Long Tank, RS-27 engine, Castor 4 motors (1975)
4: Extended Long Tank, MB-3-3 engine, Castor 4A motors (1989)
5: Extended Long Tank, RS-27 engine, Castor 4A motors (1989)
6: Extra Extended Long Tank, RS-27 engine, Castor 4A motors (1989)
7: Extra Extended Long Tank, RS-27A engine, GEM-40 motors (1990)
8: Delta 3 First Stage, RS-27A engine, GEM-46 motors (1998)
Second Digit: Number of Strap on Motors
Third Digit: Second Stage Type
0: AJ10-118F (Aerojet Transtage derivative, 1972)
1: TR-201 (TRW LM Descent Engine derivative, 1972)
2: AJ10-118K (Aerojet ITIP engine, 1982)
3: Delta Cryogenic Second Stage (1998)
Fourth Digit: Third Stage Type
0: No third stage
3: Star 37D (TE-364-3, 1968)
4: Star 37E (TE-364-4, 1972)
5: Star 48B (TE-M-799, 1989)
6: Star 37FM (1998)
7920/7925 Series Delta with GEM-46 motors (1998)
Table 2: Delta Launch Vehicle Performance,
|Delta Lite w/SRM
"Defining Aerospace Policy: Essays in Honor of Francis T.
Hoban", Edited by Kenneth John Button, Francis T. Hoban, Julianne Lammersen-Baum,
Roger Stough, Ashgate Publishing, 2004.
"Delta - A Progress Report on Latest Developments",
J.F. Meyers, McDonnell Douglas Aerospace, AIAA 1995 Space Programs and Technologies
Conference, AIAA 95-3773.
Merger Agreement Announcement, 12-15-1996.
"Boeing Delta 2 Heavy
Lift Rocket Developed for NASA Payload", Boeing, 8-31-1999.
Press Releases and Mission Press Kits by NASA, McDonnell Douglas,
Boeing, and United Launch Alliance.
Photos by NASA, USAF, McDonnell Douglas, Boeing, United Launch
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