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THE DELTA FAMILY

**Thor:** (1957) Thor IRBM with no upper stage.
**Thor Able:** (1958) Thor with Able upper stage derived from Vanguard second stage.
**Thor Agena A:** (1959) Thor with Agena A second stage.
**Delta:** (1960) Commercial name for the military's Thor-Delta. The name of the Delta second stage eventually was applied to subsequent commercial follow-ons.
**Thor Able-Star:** (1960) Thor with Able-Star second stage.
**Thor Agena B:** (1960) Thor with Agena B second stage.
**Delta A:** (1962) Upgraded Delta.
**Delta B:** (1962) Based on Delta A but with uprated second stage.
**Thor Agena D:** (1962) Thor with Agena D second stage.
**Delta C:** (1963) Same configuration as Delta B.
**Delta D:** (1964) Also known as Thrust Augmented Thor. Introduction of uprated Delta Thor TA first stage with 3 x Castor 1 solid strap-ons.
**Delta E:** (1965) Introduction of uprated Delta E second stage, FW-4D third stage, and 3 x Castor 2 solid strap-ons.
**Delta G:** (1966) Delta E less third stage and strap-ons.
**Delta J:** (1968) Based on Delta E but with Burner 2 third stage.
**Delta M:** (1968) Also known as Long Tank Thor. Based on Delta J but with larger capacity first stage and 6 strap-ons.
**Delta N:** (1968) Delta M less third stage.
**Delta L:** (1969) Delta N with FW-4D third stage.
**Delta 100:** (1972) Based on Delta M but with uprated second stage and 9 strap-ons.
**Delta 1914:** (1972) Based on Delta 100 but with uprated first stage introducing RS-27 engine.
**Delta 2914:** (1974) Based on Delta 1914 but with TR-201 stage 2 engine derived from Apollo LM descent engine.
**Delta 2910:** Configuration 2914 less Burner 2 third stage.
**Delta N:** (1975) Licensed version of Delta built in Japan using both US and Japanese components.
**Delta 3914:** (1976) Based on Delta 2914 but with uprated Castor 4 solid strap-ons.
**Thor Burner:** (1976) Thor with Burner 2 second and third stages.
**Delta 3910:** Configuration 3914 less Burner 2 third stage.
**Delta 3910/PAM:** (1980) Configuration 3910 with PAM Payload Assist Module third stage.
**Delta N-2:** (1981) Licensed version of Delta built in Japan using both US and Japanese components.
**Delta 3920:** (1982) Upgraded Delta 3910 with larger capacity second stage.
**Delta 3920/PAM:** (1982) Also known as Delta 3925. Configuration 3920 with PAM third stage.
**Delta 4925:** (1989) Based on Delta 3920/PAM but with uprated Castor 4A solid strap-ons.
**Delta 5920:** (1989) Configuration 4925 less PAM third stage.
**Delta II, 6925:** (1989) Based on Delta 4925 but with upgraded first stage.
**Delta II, 6920:** (1990) Configuration 6925 less PAM third stage.
**Delta II, 7925:** (1990) Based on Delta 6925 but with modified first stage and uprated Alliant GEM solid strap-ons.
**Delta II, 7920:** (1995) Configuration 7925 less PAM third stage.
**Delta III, 8930:** (1998) Based on Delta II first stage with larger GEM solid strap-ons and a new cryogenic upper stage.
**Delta IV, Medium:** (2003) Basic Delta IV vehicle with no strap-ons, common booster core, cryogenic upper stage, and 4 m fairing.
**Delta IV, M+ (4,2):** (2002) Same as Delta IV Medium but with two GEM-60 solid rocket motor strap-ons.
**Delta IV, Heavy:** (2004) Two Delta IV CBC strap-ons flanking CBC first stage, with heavy cyrogenic upper stage and 5-m fairing.

**DELTA FAMILY RECORD**
**First launch:** 13-May-1960
**Number launched:** 280 to Aug-2000
**Launch sites:** Cape Canaveral pads 17A/B; Vandenberg AFB SLC-2W
**Vehicle success rate:** 94.64%
**Success rate, past 25 launches:** 92% to Aug-2000

DELTA II, 7925/7920 SPECIFICATIONS

**First launch:** 26-Nov-1990
**Number launched:** 61 to Aug-2000
**Launch sites:** Cape Canaveral pads 17A/B, VAFB SLC-2W
**Principal uses:** launches of GPS Navstar Block 2A; medium class telecom satellites
into GTO
**Vehicle success rate:** 98.36% to Aug-2000
**Performance:**

GTO: 1,842 kg (1,882 kg from Dec-1995)

GPS: 2,090 kg (2,141 kg from Dec-1995)

LEO (28.7^{o}): 5,039 kg 7920 2-stage

Sun-synchronous (830 km): 3,175 kg 7920 VAFB

Molniya-type (370 x 40,000 km, 63.4^{o}): 1,275 kg

Lunar delivery: 1,240 kg
**Availability:** typically 30 months from contract signature to launch
**Number of stages:** 3 + 9 strap-ons (7920 excludes stage 3)
**Overall length:** 38.41 m
**Principal diameter:** 2.44 m
**Launch mass:** 231,870 kg
**Launch thrust:** 3,110 kN (six solids fire at launch)
**Guidance:** The digital inertial guidance system is mounted inside a cylinder at stage 2's forward end, controlling the vehicle during stage 1/2 and commanding spin-up/separation of stage 3 in addition to triggering its fuze-based sequencing system.

**ALLIANT GEM 40 SOLID STRAP-ONS**
**Length:** 12.96 m
**Diameter:** 1.02 m
**Mass at ignition:** 13,232 kg each for six ignited on pad; 13,061 kg each for three air-lit
**Propellant:** HTPB solid
**Propellant mass:** each 11,765 kg
**Thrust:** each 446.0 kN SL average, 499.2 kN vac
**Burn time:** 63.3 s
**Burn sequence:** Six GEMs are ignite at launch, followed by the remaining three 2.5 s after their burnout at 63 s. The original six are spring-separated (under command of a sequencer between stage 1's tanks) in two symmetrical sets at 66/67 s; the final three burn out at 129 s and separate 3 s later.

**DELTA 7920/7925 STAGE 1**
**Engines:** Rocketdyne RS-27A single-start liquid bipropellant; with two Rocketdyne LR-101-NA-11 verniers
**Length:** 26.05 m
**Diameter:** 2.44 m
**Stage mass:** 101,718 kg
**Oxidizer:** liquid oxygen
**Fuel:** RP-1 hydrocarbon
**Propellant mass:** 96,033 kg (usable)
**Thrust:** 890 kN SL, 1,085 kN vac + two 4.45 kN verniers
**Burn time:** 260.5 s
**Attitude control:** Main engine hydraulically gimbaled for pitch/yaw control, two verniers provide roll control.

**INTERSTAGE**

The 4.72 m long isogrid interstage extends from the top of stage 1 to stage 2's miniskirt, encircling most of the upper stage until explosive bolt detonation 8 s after stage 1 burnout; six spring-driven separation rods at the forward end then separate the stages and stage 2 ignition occurs 5 s later.

**DELTA 7920/7925 STAGE 2**
**Engine:** pressure-fed restartable Aerojet AJ10-118K
**Length:** 5.89 m
**Diameter:** 1.70 m, suspended by 2.44 m diameter mini-skirt and support truss
**Stage mass:** 6,930 kg
**Oxidizer:** nitrogen tetroxide
**Fuel:** Aerozine-50
**Propellant mass:** 6,006 kg (usable)
**Thrust:** 43.37 kN vac
**Burn time:** 432 s (restartable)
**Attitude control:** The nitrogen cold gas jet Redundant Attitude Control System (RACS) provides 3-axis control during coast periods and roll control during powered flight; hydraulic gimballing of the main engine provides pitch/yaw control.

**DELTA 7925 STAGE 3**
**Designation:** PAM-D
**Motor:** Thiokol Star 48B solid
**Length:** 2.04 m
**Diameter:** 1.24 m
**Mass at ignition:** 2,141 kg (132 kg after burnout)
**Propellant:** solid
**Propellant mass:** 1,756-2,025 kg, depending on mission requirements
**Thrust:** 66.4 kN vac
**Burn Time:** 87.1 s

**FAIRING/PAYLOAD ACCOMODATION**

The spacecraft is protected by an 8.49 m long, 839 kg aluminum fairing 2.44 m diameter at the base and 2.90 m at the widest portion. The halves are pyrotechnically separated during second stage burning at a height of about 111 km where aerodynamic heating has reduced to 1,135 W/m^{2}. Also available are 2.44/3.05 m diameter versions. Air conditioning on the pad can provide 14-26.7^{o}C, maximum humidity 50%.
**Acceleration load:** 6.25 g max at end of stage 1 burn for heaviest GTO payloads; 4.24 g at stage 3 burnout, 1.31 g at launch
**Acoustic load:** maximum about 130 dB at launch/transonic
**Temperature:** 33^{o}C max on fairing inner wall after 300 s

DELTA III, 8930 SPECIFICATIONS

**First launch:** 27-Aug-1998
**Last launch:** 23-Aug-2000
**Number launched:** 3
**Vehicle success rate:** 33.33%
**Performance:**

GTO (200 x 35,786 km, 28.7^{o}): 3,810 kg

LEO (185 km, 28.7^{o}): 8,290 kg

ISS (407 km, 51.6^{o}): 7,300 kg

Polar (200 km, 90^{o}): 6,770 kg

Sun-synchronous (800 km, 98.6^{o}): 6,100 kg
**Number of stages:** 2 + 9 strap-ons
**Overall length:** 35.0 m
**Principal diameter:** 2.44 m / 4.0 m
**Launch mass:** 301,450 kg
**Launch thrust:** 4,114 kN (six solids fire at launch)

**ALLIANT GEM 46 SOLID STRAP-ONS**
**Length:** 14.66 m
**Diameter:** 1.17 m
**Mass at ignition:** 19,327 kg each for three with thrust vector control; 19,082 kg each for six non-TVC
**Propellant:** HTPB solid
**Propellant mass:** each 17,045 kg
**Thrust:** each 537.4 kN SL average, 628.3 kN vac
**Specific impulse:** 243 s SL, 284 s vac
**Burn time:** 75.2 s
**Burn sequence:** Six GEMs are ignite at launch, followed by the remaining three after burnout.

**DELTA 8930 STAGE 1**
**Engines:** Rocketdyne RS-27A single-start liquid bipropellant; with two Rocketdyne LR-101-NA-11 verniers
**Length:** 20.0 m
**Diameter:** 2.44 m, flaring to 4.0 m at forward end
**Stage mass:** 104,380 kg
**Oxidizer:** liquid oxygen
**Fuel:** RP-1 hydrocarbon
**Propellant mass:** 95,550 kg
**Thrust:** 890 kN SL, 1,085 kN vac + two 4.45 kN verniers
**Burn time:** 261 s
**Attitude control:** Main engine hydraulically gimbaled for pitch/yaw control, two verniers provide roll control.

**DELTA 8930 STAGE 2**
**Engine:** Pratt & Whitney RL-10B-2
**Length:** 8.8 m
**Diameter:** 4.0 m
**Stage mass:** 19,300 kg
**Oxidizer:** liquid oxygen
**Fuel:** liquid hydrogen
**Propellant mass:** 16,820 kg
**Thrust:** 110.1 kN vac
**Burn time:** 700 s

DELTA IV

The Delta IV launch system comes in five vehicle configurations: the Delta IV Medium, three variants of Delta IV Medium-Plus, and the Delta IV Heavy. Each has a newly developed first stage, called the common booster core (CBC), using cryogenic propellants. The Delta IV-M employs a first-stage CBC, a 4-m diameter cryogenic second stage, and a 4-m diameter composite payload fairing (PLF). The Delta IV-M+ comes in three different configurations. One configuration uses two strap-on solid rocket motors (SRMs) to augment the first-stage CBC, a 4-m diameter cryogenic second stage, and a 4-m composite PLF. This configuration is designated as Delta IV-M+ (4,2); the first digit in parentheses refers to the diameter of the second stage, and the second digit refers to the numbers of strap-on SRMs. The other two configurations are the Delta IV-M+ (5,2) and M+ (5,4) that have two and four SRMs respectively. Both of these configurations employ a 5-m diameter cryogenic second stage and a 5-m composite PLF. The Delta IV-H employs two additional CBCs as strap-on liquid rocket boosters (LRBs) to augment the first stage CBC, a cryogenic 5-m second stage, and either a 5-m composite or 5-m metallic PLF.

**First launch:** 20-Nov-2002
**Number launched:** 4 to end-2004
**Launch sites:** Cape Canaveral SLC-37, VAFB SLC-6
**Principal uses:** delivery of single or double payloads to LEO or GTO/GEO
**Vehicle success rate:** 100% to end-2004
**Performance:**

GTO (185 x 35,786 km, 27.0^{o}): 4,231 kg (IV-M), 5,941 kg (IV-M+ 4,2), 4,869 kg (IV-M+ 5,2), 6,822 kg (IV-M+ 5,4), 12,757 kg (IV-H)

GEO (35,786 km, 0^{o}): 1,138 kg (IV-M), 2,036 kg (IV-M+ 4,2), 1,686 kg (IV-M+ 5,2), 2,786 kg (IV-M+ 5,4), 6,276 kg (IV-H)

LEO (407 km, 28.7^{o}): 9,106 kg (IV-M), 12,300 kg (IV-M+ 4,2), 10,616 kg (IV-M+ 5,2), 13,869 kg (IV-M+ 5,4), 21,892 kg (IV-H)

ISS (407 km, 51.6^{o}): 8,501 kg (IV-M), 11,455 kg (IV-M+ 4,2), 9,782 kg (IV-M+ 5,2), 12,894 kg (IV-M+ 5,4), 21,892 kg (IV-H)

Moon: 3,132 kg (IV-M), 4,445 kg (IV-M+ 4,2), 3,623 kg (IV-M+ 5,2), 4,858 kg (IV-M+ 5,4), 9,956 kg (IV-H)

Mars: 2,347 kg (IV-M), 3,465 kg (IV-M+ 4,2), 2,743 kg (IV-M+ 5,2), 3,792 kg (IV-M+ 5,4), 8,005 kg (IV-H)
**Number of stages:** 2 + 0 to 4 strap-ons
**Overall length:** 62.8 m (IV-M & IV-M+ 4,2), 66.1 m (IV-M+ 5,2 & 5,4), 71.0 m (IV-H)
**Principal diameter:** 5.13 m
**Launch mass:** 249,500 kg (IV-M), 317,100 kg (IV-M+ 4,2), 337,000 kg (IV-M+ 5,2), 404,600 kg (IV-M+ 5,4), 733,400 kg (IV-H)
**Launch thrust:** 2,891 kN (IV-M), 4,359 kN (IV-M+ 4,2 & 5,2), 5,827 kN (IV-M+ 5,4), 8,673 kN (IV-H)

**DELTA IV SOLID ROCKET MOTORS (SRM)**
**Motor:** Alliant GEM 60
**Length:** 16.15 m
**Diameter:** 1.52 m
**Mass at ignition:** 33,798 kg each with thrust vector control; 33,199 kg each for non-TVC
**Propellant:** HTPB solid
**Propellant mass:** each 29,949 kg
**Thrust:** each 734 kN SL average, 827 kN vac
**Specific impulse:** 243 s SL, 275 s vac
**Burn time:** 97 s
**Burn sequence:** Ignited at liftoff, first pair jettisoned at 100 s, second pair (if used) at 102 s.

**DELTA IV LIQUID ROCKET BOOSTERS (LRB)**

The LRBs, used on the Delta IV-H, are identical to the CBC except they are fitted with nose cones and separation motors.
**Burn sequence:** 100% thrust at liftoff, throttled to 60% at 238-244 s, cut-off at 249 s, jettisoned at 251 s.

**DELTA IV COMMON BOOSTER CORE (CBC)**
**Engine:** Rocketdyne RS-68
**Length:** 40.8 m
**Diameter:** 5.13 m
**Stage mass:** 226,400 kg
**Oxidizer:** liquid oxygen
**Fuel:** liquid hydrogen
**Propellant mass:** 199,640 kg
**Thrust:** 2,891 kN SL, 3,314 kN vac
**Burn time:** 246 s
**Attitude control:** Engine hydraulically gimbaled for pitch/yaw control. Roll for single-CBC vehicles is provided by vectoring the RS-68 turbine exhaust gases; roll for Heavy vehicle is provided by gimbaling the LRB engines.
**Burn sequence:** Delta IV-H: 100% thrust at liftoff, throttled to 60% at 56 s, throttled-up to 100% at 252-257 s, cut-off at 327 s, separation at 332 s. All others: 100% thrust, cut-off at 246 s, separation at 251 s.

**INTERSTAGE ADAPTER**

The CBC has an overall diameter of 5 m, so the interstage is tapered down to 4-m diameter for the Delta IV-M and M+ (4,2) configurations that use a 4-m cryogenic second stage. The interstages for the Delta IV-M+ (5,2), M+ (5,4), and Heavy configurations have a 5-m diameter cylinder.

**DELTA IV STAGE 2**

Two second stage configurations are offered on Delta IV, a 4-m version and a 5-m version. Both second stages use the Delta III RL10B-2 engine. Specifications below are for the 4-m version with figures for the 5-m version, where different, in parentheses.
**Engine:** Pratt & Whitney RL10B-2
**Length:** 12.2 m (13.7 m)
**Diameter:** 4.0 m (5.0 m)
**Stage mass:** 24,170 kg (30,710 kg)
**Oxidizer:** liquid oxygen
**Fuel:** liquid hydrogen
**Propellant mass:** 21,320 kg (27,220 kg)
**Thrust:** 110.1 kN vac
**Burn time:** 850 s (1,125 s)

**PAYLOAD FAIRING**

The Delta IV launch system offers PLFs for different vehicle configurations. The 4-m fairing is a stretched Delta III 4-m composite bisector design, and is 11.75 m long. The 5-m composite fairing for single-manifest missions is also based in that of Delta III and comes in two standard lengths: 14.3 m and 19.1 m. The dual-manifest fairing consists of two sections - a 5-m composite bisector fairing and a lower 5-m composite dual-payload canister (DPC), and is available in two lengths: 19.1 m and 22.4 m. The 5-m metallic trisector fairing (the baseline for government programs) is a modified version of the flight-proven Titan IV aluminum isogrid fairing, and is 19.8 m long.

ROCKETDYNE / RS-68
**Application:** Delta IV common booster core
**First flown:** 20-Nov-2002
**Dry mass:** 6,604 kg
**Mounting:** hydraulically gimbaled for pitch/yaw control
**Engine cycle:** gas generator
**Oxidizer:** liquid oxygen, delivered at 700 kg/s
**Fuel:** liquid hydrogen, delivered at 117 kg/s
**Mixture ratio:** 6.0
**Thrust:** 2,891 kN SL, 3,314 kN vac, can be throttled to 60%
**Specific impulse:** 365 s SL, 410 s vac
**Expansion ratio:** 21.5:1
**Combustion chamber pressure:** 95.9 atm

ROCKETDYNE / RS-27, RS-27A

The RS-27 powerplant comprises an RS2701A/B main engine and twin LR101-NA-11 verniers. The uprated RS-27A version is employed by the 7000 series; its specifications are given below, where different, in parentheses.
**Application:** Delta 6000 series (RS-27A: 7000 & 8000 series)
**First flown:** 18-Jan-1974 (RS-27A debut 1990)
**Number flown:** 107 Delta + 21 Atlas (RS-27A: 20) to end-1995
**Dry mass:** 1,027 kg (1,091 kg)
**Length:** 3.63 m from top of thrust ring (3.78 m)
**Maximum diameter:** 1.70 m
**Mounting:** gimbal-mounted for pitch/yaw control + gimbaled verniers for roll control
**Engine cycle:** gas generator
**Oxidizer:** liquid oxygen, delivered at 250 kg/s
**Fuel:** RP-1, delivered at 111 kg/s
**Mixture ratio:** 2.245
**Oxidizer turbopump:** 6,784 rpm (7,085 rpm at altitude), 1,900 kW, 70 atm discharge pressure
**Fuel turbopump:** 1,289 kW, 70 atm discharge pressure
**Thrust:** 971 kN SL, 1,032 kN vac (890 kN SL, 1,054.2 kN vac)
**Specific impulse:** 264 s SL, 295 s vac (255 s SL, 302 s vac)
**Expansion ratio:** 8:1 (12:1)
**Combustion chamber pressure:** 48 atm
**Combustion chamber temperature:** 3,315^{o}C
**Burn time:** 274 s
**Verniers:** each 21.8 kg mass, 4.63/5.30 kN SL/vac thrust, 206/246 s SL/vac Isp, 1.8 mixture ratio, 5.6 expansion ratio (9.8 cm exit diameter), 283 s burn time

AEROJET / AJ10-118K
**Application:** Delta II stage 2
**First flown:** Aug-1982
**Dry mass:** 124.7 kg
**Length:** 2.69 m
**Mounting:** fixed
**Engine cycle:** pressure-fed
**Oxidizer:** nitrogen tetroxide, delivered at 9.1 kg/s
**Fuel:** Aerozine-50, delivered at 4.76 kg/s
**Mixture ratio:** 1.9
**Thrust:** 43.48 kN vac
**Specific impulse:** 320.5 s vac
**Expansion ratio:** 65:1
**Combustion chamber pressure:** 8.84 atm
**Burn time:** qualified up to 500 s (unlimted starts)

P&W / RL10B-2
**Application:** Delta III & IV stage 2
**First flown:** Aug-1998
**Number flown:** 7 to end-2004
**Dry mass:** 301 kg
**Maximum diameter:** 2.14 m
**Mounting:** electromechanically gimbaled for pitch/yaw control
**Oxidizer:** liquid oxygen, delivered at 20.6 kg/s
**Fuel:** liquid hydrogen, delivered at 3.5 kg/s
**Mixture ratio:** 5.88
**Thrust:** 110.1 kN vac
**Specific impulse:** 465.5 s vac
**Expansion ratio:** 250:1 with extendable nozzle
**Burn time:** up to 1,125 s

THIOKOL / STAR 48B

The TE-M-711-17 is employed in McDonnell Douglas's PAM for satellite launches from the Space Shuttle and Delta. The TE-M-711-18 has a longer exit cone for use in launches from Delta; its specifications are given below, where different, in parentheses.
**Designation:** TE-M-711-17 (and TE-M-711-18)
**Application:** PAM for satellite launches from Shuttle and Delta
**Mass:** 2,137 kg (2,142 kg)
**Length:** 2.03 m (2.235 m)
**Diameter:** 1.245 m
**Propellant**
** type:** AP/HTPB/Al
** mass fraction:** 0.941 (0.939)
**Propellant mass:** 2,011 kg
**Burn time:** 84 s
**Thrust:** 66 kN vac average
**Specific impulse:** 286 s vac (292.1 s vac)
**Total impulse:** 5,647 kNs (5,799 kNs)