Delta 2, the Pinnacle

Delta 2, the Pinnacle

Spent GEM-40s Jettison from Delta 266 During NASA’s 1999 Stardust Launch.  On Board Cameras and Webcast Steaming Appeared During this Era.

Delta 2 led all worldwide launch vehicles in launch numbers during 1998, with 12 flights.  1999 would be the final year with a double-digit Delta 2 launch total, with ten flights.  That the pinnacle of Delta 2 service had already been passed was not apparent at the time.

Delta 2 handled four more Globalstar launches during 1999 with 7420-10C rockets, from both Cape Canaveral pads.  A 7925 orbited a lone GPS 2R satellite for the Air Force, also from the Cape.  A second launch for the Air Force, by Delta 267, a 7920-10, placed the Advanced Research and Global Observation Satellite (ARGOS) into sun-synchronous orbit from Vandenberg AFB SLC 2W on February 24, 1999. 

ARGOS was a 2.72 tonne technology test bed for the US Air Force’s Space Test Program.  Experiments included ultraviolet imaging experiments, an X-ray sensor test, ion propulsion, gas ionization physics, plume detection capabilities, and orbital debris detection.  Its launch campaign turned out to be one of those drawn-out affairs that occasionally cropped up. 

Delta 270, One of Seven Globalstar Delta 7420 Campaigns during 1998-2000, which Included Four Launches in Two Months During 1999

A January 28, 1999 attempt to launch ARGOS was aborted when one of the two first stage vernier engines failed to ignite. An investigation determined that a propellant valve on vernier engine number two failed to open on command. Valves on both vernier engines were subsequently replaced.  Several subsequent launch attempts were also scrubbed due to high winds or other issues.  On February 12, an attempt was halted after a momentary voltage spike in one of the two power sources to the first stage electronics package was observed.  The cause was traced to the first stage power and control box and electronics package in the stage center body.   Technicians replaced both units, which required new validation tests of the boxes and their wiring harnesses.

The lengthy ARGOS campaign moved the rocket back in the queue so that ARGOS was eventually launched on the “Delta 267” mission rather than the originally planned “Delta 266”.  The Delta number logo had to be repainted as a result, so that the original ARGOS launch attempt occurred with the rocket displaying the “Delta 266” number, but it eventually flew with a “267” on its side. 

The other four Delta 2 launches in 1999 were for NASA. 

Delta 265, a 7425, sent 290 kg Mars Polar Lander toward Mars from SLC 17B on January 3.  Unfortunately, MPL would disappear during its December 3 landing attempt in Mars southern polar region.  A possible, but not certain, failure mode was determined to be a spurious touchdown indication created by the shock of landing gear deployment while the lander was still hanging beneath its parachute, preventing its landing thrusters from firing, leading to a high velocity impact.

Delta 266 Stardust Launch

Delta 2, the Pinnacle

Delta 266, moved up ahead of ARGOS, was a 7426 model that boosted 384.9 kg Stardust into solar orbit on February 7, 1999 from SLC 17A.  Stardust passed within 237 kilometers of comet Wild 2 in 2004, after gaining a gravity assist during an early 2001 flyby of Earth.  The spacecraft would return the first sample of cometary debris, captured in a bizarre substance called aerogel, to Earth in 2006 in a small capsule that reentered, at the fastest speed ever achieved by a man-made object, and parachuted to a landing at the Utah Test and Training Range near Dugway Proving Ground.  After it dropped off its capsule, Stardust itself flew on in an extended mission, meeting comet Tempel 1 in February 2011 to photograph a crater left by NASA’s Deep Impact probe in 2005 before finally ending its remarkable 12 year mission.

Delta 268 boosted 1,973 kg earth resource imager Landsat 7 into a 705 km sun synchronous orbit from Vandenberg SLC 2W on April 16. 

Delta 271, a 7320-10C, orbited NASA’s Far Ultraviolet Spectroscopic Explorer (FUSE) from SLC 17A on June 24, 1999 into a 760 km x 25 deg orbit.  The 1,400 kg spacecraft carried a telescope to detect far ultraviolet spectrum light.  It operated successfully until July 2007, well beyond its three year design life.

Also read: Delta 2 Productive Years

The New Millenium

Delta 2, the Pinnacle

From 2000 through 2009 Delta 2 settled into a more moderate pace, flying an average of six times per year.  Little LEO, responsible for 18 Delta 2 launches in only three years, came to an abrupt end with a final Globalstar launch on February 8, 2000, followed soon after by the company’s bankruptcy filing.  Iridium went bankrupt in late 1999, but was able to pay for one more Delta 2 launch of in-orbit spares in 2002. 

Delta 295 Second Staged Imaged in Orbit by XSS-10

GPS flights continued, averaging nearly two per year.  One flight, by Delta 295 in 2003, carried an interesting 28 kg microsatellite named  XSS-10 (eXperimental Small Satellite 10).  XSS-10 separated from the Delta second stage after it performed its work, then tracked and followed the stage by using its on-cameras and computers to test line-of-sight guidance. A bonus was a photograph taken by XSS-10 of the Delta 2 second stage hanging in space.  

Delta 295 was the 50th consecutive Delta success, breaking the old mark.  Boeing began to add success stars to the Delta logo on subsequent rockets.  The stars had long ago filled the delta triangle.   Soon, they filled a row that surrounded the delta and a second row was begun.

NASA’s “Med-Lite” program continued to fly one to three times per year, putting up a long string of explorers with names like IMAGE (Imager for Magnetopause-to-Aurora Global Exploration), EO 1/SAC C (Earth Observing 1 and Argentina’s SAC-C, featuring Delta’s first Dual Payload Attach Fitting, or DPAF), NOAA 18, MAP (later renamed Wilkinson Microwave Anisotropy Probe or WMAP), Genesis, CONTOUR (the Comet Nucleus Tour), ICESAT(Ice, Cloud, and land Elevation Satellite), SWIFT (Gamma-Ray Burst Mission), Calipso/CloudSat, and the joint NASA/CNES Jason 2 ocean surface height measurement missions.

Delta 2 successfully launched all of these, and most of the missions themselves were highly successful, but a few suffered failures.  Genesis, a solar wind sample mission with a sample return capsule, was launched by a 7326 Delta on August 8, 2001 from SLC 17A and returned its capsule to a planned Utah desert landing on September 8, 2004.  The capsule reentered, but its parachute failed to deploy and it crashed.  Despite the impact damage, some of the sample collectors were recovered for analysis.  The failure was traced to an accelerometer installed backwards. 

CONTOUR launched from Cape Canaveral on a Delta 7425 from SLC 17A on July 3, 2002 into a highly elliptical Earth orbit.  Six weeks later, on August 15, 2002, the spacecraft fired its solid rocket motor to propel it into a comet-chasing solar orbit and was never heard from again.   Tracking telescopes subsequently saw several pieces where there should have been one spacecraft.  A failure investigation determined that plume heating from the embedded Star 30 solid motor most likely caused structural failure.

SLC 17B Mobile Service Tower Lifts Delta 286 First Stage for NASA’s 2001 MAP Mission

The “Med-Lite” missions were augmented by a steady stream of heavier NASA spacecraft launched on 7920/25 model Deltas.  These included Mars Odyssey 2001 (a long-lived Mars orbiter), Jason 1/TIMED, Aqua, Aura (polar orbiting earth observers), Gravity Probe B, Deep Impact (which released an impactor into comet 9P/Tempel and went on to flyby comet Hartley), STEREO A and B (two solar observatories launched into solar orbits, one trailing and one leading Earth), THEMIS (five satellites launched into highly elliptical orbits), Mars Exploration Rover A (Spirit), the Mars Phoenix lander (a successful 2007 reprise of the failed Mars Polar Lander using MPL spares), and 1.052 tonne exoplanet-searcher Kepler, the latter into a heliocentric Earth-trailing orbit.  

Delta 2 performed an occasional experimental mission for the Pentagon.  Delta 2 7920/25 series vehicles launched GeoLite (USA 158), a geosynchronous orbit technology demonstration satellite, in 2001, the curious Micro-satellite Technology Experiment (MITEx), consisting of two maneuverable “inspection satellites” and an experimental Naval Research Lab upper stage, to GTO in 2006, and a series of LEO Space Tracking and Surveillance System (STSS) satellites on two launches in 2009, including STSS-ATRR (USA 205) and STSS 1/2 (USA 208-209).

Delta 2 continued to orbit commercial satellites, launching seven commercial “spy” earth observing satellites between 2001 and 2010, all from Vandenberg AFB.  A 7320-10C orbited Quickbird 2 in 2001.  Delta 7420-10C series rockets orbited COSMO 1, 2, 3 and 4 between 2007 and 2010.  Delta 7920-10C launchers boosted WorldView 1 and 2 into orbit in 2007 and 2009, respectfully.

Delta 2 “Heavy”

Delta 2, the Pinnacle

Delta 300, the Second Delta 2 “Heavy”, Launched SIRTF on August 25, 2003

An even more powerful Delta 2 variant was needed for some NASA missions.  These 7920H and 7925H rockets were created by using larger GEM-46 solid rocket motors reassigned from the terminated Delta 3 program.  Delta 7920/25H could lift 6.14 tonnes to LEO, 2.19 tonnes to GTO, or 1.519 tonnes to escape velocity from Cape Canaveral’s SLC 17B – the only pad rebuilt to handle the higher thrust motors.

Delta 299 was the first “Heavy”, a 7925H that boosted Mars Exploration Rover B (Opportunity) toward Mars on July 8, 2003.  Six weeks later, Delta 300, a 7920H, launched SIRTF (Space Infrared Telescope Facility, later renamed Spitzer Space Telescope) into solar, earth-trailing orbit.   Delta 7925H rockets launched planet Mercury orbiter MESSENGER on August 3, 2004 and asteroid Vesta and Ceres orbiter Dawn on September 27, 2007. 

Two final 7920H vehicles boosted GLAST (Gamma-ray Large Area Space Telescope, later renamed Fermi Gamma-ray Space Telescope) on June 11, 2008 and, in a final flourish, GRAIL A and B on September 10, 2011.  The twin GRAIL spacecraft orbited the Moon in tandem to map lunar gravity in unprecedented detail.

United Launch Alliance

Delta 2, the Pinnacle

Delta 328 and 325 (right) First Stages in Cape Canaveral’s Delta Mission Checkout Facility (DMCO) in Hanger AO in 2007.  Stage on Left was Example of Delta Stages Kept on 60-Day Standby for USAF GPS Missions.

Boeing moved Delta 2 finally assembly from Pueblo, Colorado to its new Delta 4 factory in Decatur, Alabama in July 2004.  The move was part of a general program consolidation that included personnel cuts in Huntington Beach, at the pads, and elsewhere and that saw second stage tank production outsourced from Huntington Beach to Alenia in Italy.

Delta 2 was folded into the United Launch Alliance (ULA) joint venture in 2006.  Boeing and Lockheed Martin spun off their space launch divisions to create ULA, primarily as a means to cut costs in their EELV (Delta 4 and Atlas 5) programs.  ULA consolidated program engineering from Huntington Beach to Denver, Colorado.

Delta 322, a 7920-10C, was the first ULA launch.  It carried NROL 21 into low earth orbit from Vandenberg on December 14, 2006.  The classified National Reconnaissance Office payload entered a 350 km x 58.48 deg orbit, but the satellite soon reportedly failed and its orbit began to decay.   On February 21, 2008, NROL 21 completed its strange journey when it was intercepted in orbit by an ASAT launched by a modified SM-3 missile from the USS Lake Erie positioned in the central Pacific Ocean.  

Delta 322 also featured the last star-filled Delta logo on its interstage.  There were 70 stars now, as the consecutive success record continued, but ULA’s commitment to cost reduction brought an end to the practice.  Future Delta 2 rockets would have a plain triangle with only a number inside.  (In 2012, even the number disappeared from logos applied to Delta 4 rockets.) 

Delta 327, a 7920H “Heavy”, Launched DAWN, fittingly enough at dawn, from SLC 17B on September 27, 2007.  Note the Plain ULA-era Delta Logo.

It was the end of a long tradition that began on July 19, 1967, when Delta 50, an “E1” model, sported a logo with only 17 white stars.  NASA Goddard’s Bill Schindler, long credited with Delta’s early program success, was Delta program manager then. 

If he didn’t conjure the stars himself, he surely enjoyed their symbolism.  Schindler, an ex-Navy Vanguard program member and NASA youngest program manager, set high “standard of excellence” goals for his agency/contractor team during his 1964-1976 run at the helm.  The success stars exhibited the results of those standards as time passed.  

Delta 343 performed the final GPS launch from SLC 17A on August 17, 2009.  GPS 2RM-8, the 48th successful GPS launch, entered its planned transfer orbit.  It was the final flight of the Star 48B third stage on a Delta 2, and the final use of Cape Canaveral Space Launch Complex 17A.

Delta 350, which launched COSMO 4, was the lone Delta 2 launch in 2010, making it the slowest year for Delta since 1988.   The program was slowing toward an apparent ending.  Delta’s long-standing GPS satellite launch work was being shifted to the new EELVs, with heavier satellites being launched directly to their operational orbits rather than being deposited in transfer orbits as Delta 2 had done. 

When the Air Force decided to end its use of Delta 2, its costs to other users, especially NASA, soared.  Its backlog dwindled, even as ULA offered to continue the program, but long term parts production ended.  Rocketdyne and Aerojet produced their final engines during the early 2000s.  The supply of Delta 2 GEM-40 solid rocket motors dwindled, though a number of bigger GEM-46 motor sets remained. 

Delta 339 Second Stage Lift Preparations During 2009 Kepler Launch Campaign.  Aerojet-Powered ITIP Stage was Largely Unchanged from 1982 Inception.  Its Tank Diameter Traced Back to 1960 Able-Star Stage.

Delta 354, a 7320, performed the 31st “Med-Lite” launch on June 10, 2011 from SLC 2W with Aquarius.  It was the 13th flight of a 732X series vehicle. 

The GRAIL A/B launch, performed by Delta 356 on September 10, 2011, was the last Thor-Delta launch from Cape Canaveral.   Delta 356 lifted off from Space Launch Complex 17B.  It was from this launch pad that Thor 101 had attempted the first Thor launch nearly 55 years before, on January 25, 1957 and that Thor 105 had scored the first program success nearly eight months later.   From 17B Delta had launched Telstar 1, Syncom 1, Wind, NEAR, Mars Pathfinder, Opportunity, Messenger, Deep Impact, Dawn, and Kepler among many notable missions.

The pad handled the first “Extended Long Tank”, “Straight Eight” and “Delta 3” models.  In the end, Pad 17B hosted a total of 164 launches while 17A handled 161.  Nearby, long-dormant Pad 18B supported 17 Thor missile research and development launches during the 1958-60 period.  

Close-Out, and Reprieve

Delta 2, the Pinnacle

On October 28, 2011, Delta 357 orbited NPOESS (National Polar-orbiting Operational Environmental Satellite System Preparatory Project) from Vandenberg AFB Space Launch Complex 2 West.  It was the final Delta 2 launch on the manifest at the time. 

Delta 341 Illustrates Delta 2’s Aggressive Early Pitch Profile During 2009 STSS-ATRR Mission

Delta’s second stage fired twice to place 1,970 kg NPP into a 824 km x 98 deg sun synchronous orbit during a 59 minute flight.   The second stage then performed two final burns (evasive and depletion).  Ball Aerospace  built NPP using a BCP2000 bus.   The satellite carried several new sensors originally developed for NPOESS, a program subsequently restructured into the  Joint Polar Satellite System (JPSS), whose first satellite was scheduled in 2015.  Fittingly, Delta 2 had been selected to serve as a reliable backstop for a troubled satellite program.  

Delta 357 was a Delta 2-7920-10C with nine strap-on motors on a two-stage core vehicle topped by a 10 foot diameter composite payload fairing.   It was the 151st Delta 2, the 340th Thor-family Delta, the 606th Thor family orbital launch, and the 719th launch of any type by a Thor family rocket.  

It was also the 96th consecutive Delta 2 success – an unprecedented mark for a U.S. orbital launcher..  The Thor family had by then performed more orbital launches than any other rocket in the world except for Russia’s R-7.   

Unassembled parts for up to five more unassigned Delta 2 vehicles existed, but their GEM-46 “Heavy” type solid motors could not fly from SLC 2 West.  Since potential Delta 2 NASA payloads required near polar orbits and Vandenberg launches, GEM motor production would have to be restarted.  United Launch Alliance nonetheless offered Delta 2 for several NASA missions.

View of Delta 2 (Here No. 344) on Cape’s SLC 17B from Press Site was Familiar During the Delta 2 Era, but SLC 17 saw Final Launch in 2011.

For months no word was heard on future launch possibilities.  Then, on July 16, 2012, NASA announced that it had awarded launch services contracts for three United Launch Alliance Delta 2 rockets and for one SpaceX Falcon 9 vehicle, all to launch from California’s Vandenberg Air Force Base. 

Delta 2 won contracts to launch the Soil Moisture Active Passive (SMAP) satellite during October 2014, the Orbiting Carbon Observatory-2 (OCO-2) during July 2014, and the Joint Polar Satellite System-1 (JPSS-1) spacecraft during November 2016.  The total cost for the three launches, including payload processing and other mission-unique ground support, was about $412 million. 

The three rockets, which will fly from Space Launch Complex 2 West toward sun synchronous low earth orbits, will largely be assembled from already-manufactured stockpiled components, such as engines, tank panels, and avionics.  ATK would manufacture new solid rocket motor sets for the 7X20-series rockets.  Parts for two additional unassigned Delta 2 rockets remained at the time. 

Vandenberg AFB SLC 2W will see More Delta 2’s, like Delta 357, which was the Last Delta 2 Before Flight Gap.

On February 22, 2013, NASA announced that it had assigned a fourth Delta 2 to launch the Ice, Cloud and Land Elevation Satellite (ICESat)-2 into near polar obit from Vandenberg AFB, a launch then scheduled for July 2016.  A firm fixed-price launch service task order was awarded for the Delta 7320-10C launch under the indefinite-delivery, indefinite-quantity NASA Launch Services (NLS) II contract.  NASA’s total cost to launch ICESat-2 would be $96.6 million, including payload processing, integrated services, telemetry, reimbursables and other launch support requirements.

2012 was the first year without a Thor or Thor/Delta launch since 1985, and only the second year without a Thor family launch since 1957.  2012 was also the first year without a Rocketdyne kerosene fueled engine launch since 1957.

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 Types

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)

“H” Designation

7920/7925 Series Delta with GEM-46 motors (1998)

Table 2:  Delta Launch Vehicle Performance, 1990-2011

Vehicle185kmx28.5 deg185kmx90 degGTOx28.7 degC3=0
Delta Lite
(not developed)
1.985 tonnes1.510 tonnes0.660 tonnes~0.444 t
Delta Lite w/SRM
(not developed)
2.610 t2.030 t0.860 t~0.579 t
Delta 7320/73262.865 t2.095 t0.950 t0.629 t
Delta 7420/74253.200 t2.460 t1.140 t0.806 t
Delta 7920/79255.045 t3.830 t1.820 t1.284 t
Delta 7920H/7925H6.140 tn/a2.190 t1.508 t
Delta 89308.290 tn/a3.800 t2.720 t

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