Pegasus rockets are the winged space booster vehicles used in an expendable launch

system developed by Orbital Sciences Corporation (Orbital). Three mainstages burning solid

propellant provide most of the thrust.

The Pegasus is carried aloft below a carrier aircraft and launched at approximately 40,000 ft (12,000 m).

The carrier aircraft provides flexibility to launch the rocket from anywhere rather than just a fixed pad. A

high-altitude launch also allows the rocket to avoid flight in the densest part of the atmosphere where

more rocket fuel, and thus a larger launch vehicle, would be needed to overcome air friction.

It flies as a rocket-powered aircraft before leaving the atmosphere. It is capable of placing small payloads

into low-Earth orbits.

Contents

 [hide]

1 Pegasus program

2 Launch profile

3 Carrier aircraft

4 Related projects

5 Launch history

6 See also

7 References

8 External links

[edit]Pegasus program

Preparations for launch of Pegasus XL carrying the NASA Interstellar Boundary Explorer (IBEX) spacecraft.

The Pegasus XL with fairing removed exposing payload bay and the IBEX satellite

The Pegasus's three Orion solid motors were developed by Hercules Aerospace (now Alliant

Techsystems) specifically for the Pegasus launcher. Additionally, wing and tail assemblies and a payload

fairing were developed. Most of the Pegasus was designed by a design team led by Dr. Antonio Elias.

The wing was designed by Burt Rutan.

Mass: 18,500 kg (Pegasus), 23,130 kg (Pegasus XL)

Length: 16.9 m (Pegasus), 17.6 m (Pegasus XL)

Diameter: 1.27 m

Wing span: 6.7 m

Payload: 443 kg (1.18 m diameter, 2.13 m length)

Orbital's internal projects, the Orbcomm communications constellation and the OrbView observation

satellites, plus Orbcomm-derived satellites (the "Microstar" platform) served as guaranteed customers

and additional seed money. Soon after development began, several government and military orders were

placed, as theScout launcher was slated for phaseout.

The first successful Pegasus launch occurred on April 5, 1990 with NASA test pilot and former

astronaut Gordon Fullerton in command of the carrier aircraft. Initially, a NASA-owned B-52

Stratofortress NB-008 served as the carrier aircraft. By 1994, Orbital had transitioned to their

"Stargazer" L-1011, a converted airliner which was formerly owned by Air Canada. The name "Stargazer"

is an inside joke—in Star Trek: The Next Generation, Captain Picard was captain of a ship

named Stargazer (his previous command to the Enterprise-D), and first officer Riker served aboard a ship

named Pegasus (his first assignment), prior to their reporting to the Enterprise-D in the pilot episode. (An

interesting point, undoubtedly not part of the in-joke, is that both fictional ships were lost while those

officers, respectively, served on them.)

The Pegasus XL, introduced in 1994 has lengthened stages to increase payload performance. In the

Pegasus XL, the first and second stages are lengthened into the Orion 50SXL and Orion 50XL,

respectively. Higher stages are unchanged; flight operations are similar. The wing is strengthened slightly

to handle the higher weight. The standard Pegasus has been discontinued; the Pegasus XL is still being

produced. Pegasus has flown 38 missions in both configurations as of April 25, 2006. Of these, 35 were

considered successful launches.

Dual payloads can be launched, with a canister that encloses the lower spacecraft and mounts the upper

spacecraft. The upper spacecraft deploys, the canister opens, then the lower spacecraft separates from

the third-stage adapter. Since the fairing is unchanged for cost and aerodynamic reasons, each of the two

payloads must be relatively compact.

For their work in developing the rocket, the Pegasus team led by Dr. Antonio Elias was awarded the

1991 National Medal of Technology by U.S. President George H. W. Bush.

The initial launch price offered was US$6 million, without options or a HAPS (Hydrazine Auxiliary

Propulsion System) maneuvering stage. With the enlargement to Pegasus XL, prices increased. At the

same time, many improvements were made in the wake of early launch failures, requiring more money. In

addition, customers usually purchase additional services, such as extra testing, design and analysis, and

launch-site support. A launch package is then approximately US$30 million in total. Some customers also

have OSC provide mission hardware, up to a fully functional spacecraft such as a Microstar. Such

packages can be much higher in cost.

By weight, Pegasus is one of the most expensive "launch-to-orbit" vehicles,[citation needed] however, for many

small satellites it is desirable to be the primary payload and be placed into the orbit desired, as opposed

to being a secondary payload placed in a compromise orbit. For example, Pegasus launches from

equatorial launch sites can put spacecraft in orbits avoiding the South Atlantic Anomaly (a high radiation

region over the South Atlantic ocean) which is desirable for many scientific spacecraft.

[edit]Launch profile

Orbital's Lockheed L-1011 Stargazer launches Pegasus carrying the three Space Technology 5satellites, 2006

Pegasus engine fires following release from its host, a B-52 Stratofortress, 1991

In a Pegasus launch, the carrier aircraft takes off from a runway with support and checkout facilities. Such

locations have included Kennedy Space Center /Cape Canaveral Air Force Station, Florida; Vandenberg

Air Force Base and Dryden Flight Research Center, California; Wallops Flight Facility,

Virginia; KwajaleinRange in the Pacific Ocean, and the Canary Islands in the Atlantic. Orbital offers

launches from Alcantara, Brazil, but no known customers have performed any. The capabilities of

Alcantara are superfluous to other sites, without being any more convenient.

Upon reaching a predetermined staging time, location, and velocity vector, the aircraft releases the

Pegasus. After five seconds of free-fall, the first stage ignites and the vehicle pitches up. The 45-degree

delta wing (of carbon composite construction and double-wedge airfoil) aids pitch-up and provides some

lift. The tail fins provide steering for first-stage flight, as the Orion 50S motor does not have a thrust-

vectoring nozzle.

Approximately 1 minute and 17 seconds later, the Orion 50S motor burns out. The vehicle is at over

200,000 feet in altitude and hypersonic speed. The first stage falls away, taking the wing and tail surfaces,

and the second stage ignites. The Orion 50 burns for approximately 1 minute and 18 seconds. Attitude

control is by thrust vectoring the Orion 50 motor in two dimensions, pitch and yaw; roll control is provided

by the nitrogen thrusters on the third stage.

Midway through second-stage flight, the launcher has reached a near-vacuum altitude. The fairing splits

and falls away, uncovering the payload and third stage. Upon burnout of the second stage's motor, the

stack coasts until reaching a suitable point in its trajectory, depending on mission. Then the Orion 50 is

discarded, and the third stage's Orion 38 motor ignites. It too has a thrust-vectoring nozzle, assisted by

the nitrogen thrusters for roll. After approximately 64 seconds, the third stage burns out.

A fourth stage is sometimes added for a higher altitude, finer altitude accuracy, or more complex

maneuvers. The HAPS (Hydrazine Auxiliary Propulsion System) is powered by three

restartable, monopropellant hydrazine thrusters. As with dual launches, the HAPS cuts into the fixed

volume available for payload. In at least one instance, the spacecraft was built around the HAPS.

Guidance is via a 32-bit computer and an IMU. A GPS receiver gives additional information. Due to the air

launch and wing lift, the first-stage flight algorithm is custom-designed. The second- and third-stage

trajectories are ballistic, though, and their guidance is derived from a Space Shuttle algorithm.

[edit]Carrier aircraft

DART spacecraft and Pegasus launch vehicle attached underneath Orbital's L-1011 aircraft

The Pegasus XL rocket attached to the underside of the Lockheed L-1011 carrier aircraft

The Pegasus XL rocket attached to the underside of the Lockheed L-1011 carrier aircraft (aft view)

It may seem at first glance that the aircraft serves as a booster to increase payloads. In fact, air launch is

largely used to reduce cost. 40,000 feet is only about 10% of the minimum altitude needed for a

temporarily-stable orbit, and 4% of a generally-stable low earth orbit. The airliner is designed for

approximately Mach 0.8; this is about 3% of orbital velocity.

The single biggest cause of traditional launch delays is weather. Carriage to 40,000 feet takes the booster

above the troposphere, into the stratosphere. Conventional weather is limited to the troposphere, and

crosswinds are much gentler at 40,000 feet. Thus the Pegasus is largely immune to weather-induced

delays, and their associated costs, once at altitude. (Bad weather is still a factor during takeoff, ascent,

and the transit to the staging point).

Air launching reduces range costs. No blastproof pad, blockhouse, or associated equipment are needed.

This permits takeoff from a wide variety of sites, generally limited by the support and preparation

requirements of the payload. The travel range of the aircraft allows launches at the equator, which

increases performance and is a requirement for some mission orbits. Launching over oceans also

reduces insurance costs, which are often large for a vehicle filled with volatile fuel and oxidizer.

Launch at altitude allows a larger, more efficient, yet cheaper first-stage nozzle. Its expansion ratio can be

designed for low ambient air pressures, without risking flow separation and flight instability during low-

altitude flight. The extra diameter of the high-altitude nozzle would be difficult to gimbal. But with reduced

crosswinds, the fins can provide sufficient first-stage steering. This allows a fixed nozzle, which saves

cost and weight versus a hot joint.

A single-impulse launch results in an elliptical orbit, with a high apogee and low perigee. The use of three

stages, plus the coast period between second and third stage firings, help to circularize the orbit, ensuring

the perigee clears the Earth's atmosphere. If the Pegasus launch had begun at low altitude, the coast

period or thrust profile of the stages would have to be modified to prevent skimming of the atmosphere

after one pass.

For launches which do not originate from Vandenberg Air Force Base, the carrier aircraft is also used to

ferry the assembled launch vehicle to the launch site. For such missions, the payload can either be

installed at the base and ferry with the launch vehicle or be installed at the launch site.

[edit]Related projects

Pegasus components have also been the basis of other OSC launchers. The ground-launched Taurus

rocket places the Pegasus stages and a larger fairing atop aCastor 120 first stage, derived from the first

stage of the MX Peacekeeper missile. Initial launches used refurbished MX first stages.

The Minotaur I, also ground-launched, is a combination of stages from Taurus launchers and Minuteman

missiles, hence the name. The first two stages are from aMinuteman II; the upper stages are Orion 50XL

and 38. Due to the use of surplus military rocket motors, it is only used for US Government and

government-sponsored payloads.

A third vehicle is dubbed Minotaur V despite containing no Minuteman stages. It consists of a refurbished

MX with an Orion 38 added as a fourth stage.

The NASA X-43A hypersonic test vehicles were boosted by Pegasus first stages. The upper stages were

replaced by exposed models of a scramjet-powered vehicle. The Orion stages boosted the X-43 to its

ignition speed and altitude, and were discarded. After firing the scramjet and gathering flight data, the test

vehicles also fell into the Pacific.

From Wikipedia, the free encyclopedia

  (Redirected from Titan rocket)

See also: LGM-25 Titan

Titan family

The Titan rocket family.

Role Expendable launch system with various applications

Manufacturer Glenn L. Martin Company

First flight 1958-12-20[1]

Introduction 1959

Retired 2005

Primary users United States Air ForceNational Aeronautics and Space Administration

Produced 1957-2000s

Number built 368

Unit cost US$250-350 million

Variants Titan ITitan IITitan IIIATitan IIIBTitan IIICTitan IIIDTitan IIIETitan 34DTitan IV

Titan was a family of U.S. expendable rockets used between 1959 and 2005. A total of 368 rockets of this

family were launched, including all the Project Gemini manned flights of the mid-1960s. Titans were part

of the American intercontinental ballistic missile deterrent until the late 1980s, and lifted other American

military payloads as well as civilian agency intelligence-gathering satellites. Titans also were used to send

highly successful interplanetary scientific probes to Mars, Jupiter, Saturn, Uranus and Neptune.

Contents

 [hide]

1 Titan I

2 Titan II

3 Titan III

4 Titan IV

5 Rocket fuel

6 Current status of Titans

7 Specifications

8 See also

9 Notes

10 References

11 External links

[edit]Titan I

The Titan I was the first version of the Titan family of rockets. It began as a backup ICBM project in case

the Atlas was delayed. It was a two-stage rocket powered by RP-1 and Liquid Oxygen. It was operational

from early 1962 to mid-1965.

[edit]Titan II

Most of the Titan rockets were the Titan II ICBM and their civilian derivatives for NASA. The Titan II used

a hypergolic combination of nitrogen tetroxide andAerozine 50 (a 50/50 mix of hydrazine and UDMH) for

its oxidizer and fuel.

The first Titan II guidance system was built by AC Spark Plug. It used an IMU (inertial measurement unit,

a gyroscopic sensor) made by AC Spark Plug derived from original designs from MIT Draper Labs. The

missile guidance computer (MGC) was the IBM ASC-15. When spares for this system became hard to

obtain, it was replaced by a more modern guidance system, the Delco Universal Space Guidance System

(USGS). The USGS used a Carousel IV IMU and a Magic 352 computer.[2]

The most important use of the civilian Titan II was in the NASA Gemini program of manned space

capsules in the mid-1960s. Twelve Titan IIs were used to launch two U.S. unmanned Gemini test

launches and ten manned capsules with two-man crews. All of the launches were successes.

Also, in the late 80s some of the deactivated Titan IIs were converted into space launch vehicles to be

used for launching U.S. Government payloads. The final such vehicle launched a Defense Meteorological

Satellite Program (DMSP) weather satellite from Vandenberg Air Force Base, California, on 18 October

2003.[3]

[edit]Titan III

The Titan III was a modified Titan II with optional solid rocket boosters. It was developed by the U.S. Air

Force as a heavy-lift satellite launcher to be used mainly to launch American military payloads and civilian

intelligence agency satellites such as the Vela Hotel nuclear-test-ban monitoring satellites, observation

and reconnaissance satellites (for intelligence-gathering), and various series of defense communications

satellites.

The Titan IIIA was a prototype rocket booster, which consisted of a standard Titan II rocket with

a transtage upper stage. The Titan IIIB with its different versions (23B, 24B, 33B, and 34B) had the Titan

III core booster with an Agena D upper stage. This combination was used to launch the KH-8 GAMBIT

series of intelligence-gathering satellites. They were all launched from Vandenberg Air Force

Base, California, due south over the Pacific into polar orbits. Their maximum payload mass was about

7,500 lb (3,000 kg).

The powerful Titan IIIC used a Titan III core rocket with two large strap-on solid-fuel boosters to increase

its launch thrust, and hence the maximum payload mass capability. The solid-fuel boosters that were

developed for the Titan IIIC represented a significant engineering advance over previous solid-fueled

rockets, due to their large size and thrust, and their advanced thrust-vector control systems. The Titan

IIID was a derivative of the Titan IIIC, without the upper transtage, that was used to place members of

the Key Hole series of reconnaissance satellites for the intelligence agencies into low Earth orbits.

The Titan IIIE, the one with an additional high-specific-impulse Centaur upper stage, was used to launch

several scientific spacecraft, including both of NASA's two Voyager space probes to Jupiter, Saturn and

beyond, and both of the twoViking missions to place two orbiters around Mars and two instrumented

landers on its surface.

The first guidance system for the Titan III used the AC Spark Plug company IMU (inertial measurement

unit) and an IBM ASC-15 guidance computer from the Titan II. For the Titan III, the ASC-15 drum memory

of the computer was lengthened to add 20 more usable tracks, which increased its memory capacity by

35%.[4]

The more-advanced Titan IIIC used the Delco Carousel VI IMU and the Magic 352 guidance computer.[5]

[edit]Titan IV

The Titan IV is a "stretched" Titan III with non-optional solid rocket boosters on the two sides. The Titan

IV could be launched with either the Centaur upper stage, the NASA Inertial Upper Stage (IUS), or no

upper stage at all. This rocket was used almost exclusively to launch American military or civilian

intelligence agency payloads. However it was also used for a purely scientific purpose to launch the

NASA - ESA Cassini / Huygens space probe to Saturn in 1997. The primary intelligence agency that

needed the Titan IV's launch capabilities was the National Reconnaissance Office, the NRO.

By the time it became available, the Titan IV was the most powerful unmanned rocket produced and used

by United States, because the extremely large and powerful Saturn V rocket had been no longer available

for some years. Still, the Titan IV was considered to be quite expensive to manufacture and use. By the

time the Titan IV became operational, the requirements of the U.S. Department of Defense and the NRO

for launching satellites had tapered off due to improvements in the longevity of reconnaissance satellites,

and in addition, the declining foreign threat to the security of the United States that followed the internal

disintegration of the Soviet Union.

As a result of these events, and improvements in technology, when including the cost of the ground

operations and facilities for the Titan IV at Vandenberg Air Force Base for launching satellites into polar

orbits, the unit cost of a Titan IV launch was very high. Titan IVs were also launched from the John F.

Kennedy Space Center in Florida for non-polar orbits..

[edit]Rocket fuel

Liquid oxygen is dangerous to use in an enclosed space, such as a missile silo, and cannot be stored for

long periods in the booster oxidizer tank. Several Atlas and Titan I rockets exploded and destroyed their

silos. The Martin Company was able to improve the design with the Titan II. The RP-1/LOX combination

was replaced by a room-temperature fuel whose oxidizer did not require cryogenic storage. The same

first stage rocket engines were used with some modifications. The diameter of the second stage was

increased to match the first stage. The Titan II's hypergolic fuel and oxidizer ignited on contact, but they

were highly toxic and corrosive liquids. The fuel was Aerozine 50 (a 50/50 mix of hydrazine and UDMH)

and the oxidizer was nitrogen tetroxide.

There were several accidents in Titan II silos resulting in loss of life and/or serious injuries. In August

1965, 53 construction workers were killed when hydraulic fluid used in the Titan II caught fire in a missile

silo northwest of Searcy, Arkansas.[6] The liquid fuel missiles were prone to developing leaks of their toxic

propellants. One airman was killed at a site outside Rock, Kansas, on August 24, 1978 when a missile in

its silo leaked propellant.[7][8] Later, another site, at Potwin, Kansas, leaked fuel and was closed, but there

were no fatalities. In September 1980, at another Titan II silo (374-7) near Damascus, Arkansas, a

technician dropped a wrench that broke the skin of the missile. Leaking rocket fuel ignited and blew the

8,000 lb nuclear warhead out of the silo. It landed harmlessly several hundred feet away.[9] This marked

the beginning of the end for the Titan II as an ICBM. The 54 Titan II's were replaced in the U.S. arsenal by

50 MX "Peacekeeper" solid-fuel rocket missiles in late 1980s. 54 Titan IIs had been fielded along with

some 1000 Minutemenfrom the mid-1960s through the mid-1980s. Most of the decommissioned Titan II

ICBMs were refurbished and used for Air Force space launch vehicles, with a perfect launch success

record.

[edit]Current status of Titans

The last Titan rocket launched, a Titan IV B

As of 2006, the Titan family of rockets is obsolete. The high cost of using hydrazine and nitrogen

tetroxide, along with the special care that was needed due to their toxicity, proved too much compared to

the higher-performance liquid hydrogen or RP-1-fueled vehicles (kerosene), with a liquid oxygen oxidizer.

The current owners of the Titan family of rockets, the Lockheed-Martin company, decided to extend

its Atlas family of rockets instead of its more expensive Titans—along with participating in joint-ventures

to sell launches on the Russian Proton rocket and the new Boeing-built Delta IV class of medium and

heavy-lift launch vehicles. The next-to-last Titan rocket was launched successfully from Cape Canaveral

on 29 April 2005. The final Titan rocket was launched successfully from Vandenberg Air Force Base on

19 October 2005, carrying a secret payload for the National Reconnaissance Office (NRO). There are

about twenty Titan II rockets at the Aerospace Maintenance and Regeneration Centernear Tucson,

Arizona, that are set to either be scrapped or used as monuments.[10]

A replica of a Titan II rocket is the centerpiece of the Kansas Cosmosphere and Space Center aerospace

museum in Hutchinson, Kansas.

Ariane is a series of a European civilian expendable launch vehicles for space launch use. The name

comes from the French spelling of the mythological characterAriadne; the word is also used in French to

describe some types of hummingbird.

France first proposed the Ariane project and it was officially agreed upon at the end of 1973 after delicate

discussions between France, Germany and the UK. The project was Western Europe's second attempt to

develop its own launcher following the unsuccessful Europa project. The Ariane project was code-named

L3S (the French abbreviation for third-generation substitution launcher). The European Space

Agency (ESA) changed the EADS subsidiary EADS Astrium to the development of all Ariane launchers

and of the testing facilities, while Arianespace, a 32.5% CNES commercial subsidiary created in 1980,

handles production, operations and marketing.

Arianespace launches Ariane rockets from the Centre Spatial Guyanais at Kourou in French Guiana,

where the proximity to the equator gives a significant advantage for the launch.

Contents

 [hide]

1 Ariane versions

2 Industrials

3 Ariane's Cup

4 Models

5 See also

6 References

7 External links

[edit]Ariane versions

The several versions of the launcher include:

Ariane 1, first successful launch on December 24, 1979

Ariane 2, first successful launch on November 20, 1987 (the first launch on May 30, 1986 failed)

Ariane 3, first successful launch on August 4, 1984

Ariane 4, first successful launch on June 15, 1988

Ariane 5, first successful launch on October 30, 1997 (the first launch on June 4, 1996 failed).

The Ariane 5

Ariane 1 was a three-stage launcher, derived from missile technology. Arianes 2 through 4 are

enhancements of the basic vehicle. The major differences are improved versions of the engines, allowing

stretched first- and third-stage tanks and greater payloads. The largest versions can launch two satellites,

mounted in the SPELDA (Structure Porteuse Externe pour Lancements Doubles Ariane) adapter.

Such later versions are often seen with strap-on boosters. These layouts are designated by suffixes after

the generation number. First is the total number of boosters, then letters designatingliquid- or solid-

fueled stages. For example, an Ariane 42P is an Ariane 4 with two solid-fuel boosters. An Ariane 44LP

has two solid, two liquid boosters, and a 44L has four liquid-fuel boosters.

Ariane 5 is a nearly-complete redesign. The two storable lower stages are replaced with a single,

cryogenic core stage. This simplifies the stack, along with the use of a single core engine (Vulcain).

Because the core cannot lift its own weight, two solid-fuel boosters are strapped to the sides. The

boosters can be recovered for examination but are not reused. The upper stage is storable and

restartable, powered by a single Aestus engine.[1]

In addition, the Ariane 5 is capable of launching the heaviest loads available below the needs of a heavy

lifter like the Saturn V, Energiya or Ares V. On 4 May 2007, an Ariane 5-ECA rocket set a new

commercial payload record, lifting two satellites with a combined mass of 9.4 tonnes.[2]

As of January 2006, 169 Ariane flights have boosted 290 satellites, successfully placing 271 of them on

orbit (223 main passengers and 48 auxiliary passengers) for a total mass of 575,000 kg successfully

delivered on orbit.[citation needed] Attesting to the ubiquity of Ariane launch vehicles, France's Cerise satellite,

which was orbited by an Ariane in 1995,[3] struck a discarded Ariane rocket stage in 1996.[4] The incident

marked the first verified case of a collision with a piece of cataloged space debris.[5]

[edit]Industrials

Arianespace has 24 shareholders from 10 European countries, including:[6]

CNES (34%)

EADS (30%)

Country Shareholders Capital

 Belgium 3 3.15%

 Denmark 1 0.01%

 France 7 60.12%

 Germany 2 18.62%

 Italy 2 9.36%

 Netherlands 1 1.82%

 Norway 1 0.10%

 Spain 3 2.01%

 Sweden 2 2.30%

 Switzerland 2 2.51%

Total of 99.99% due to round-off

Corporate management is structured as follows:

Position Name

CEO & Chairman Jean-Yves Le Gall

Quality Vice-President Gérard Gradel

Senior Vice-President of Programs Patrick Bonguet

Senior Vice-President of Marketing Philippe Berterottière

General Secretary, Senior Vice-President of Finances Françoise Bouzitat

Senior Vice-President of Engineering Édouard Perez

Delta is a family of expendable launch systems that have provided space launch capability in the United

States since 1960. There have been over 300 Deltarockets launched, with a 95% success rate. Two Delta

launch systems – Delta II and Delta IV – are in active use. Delta rockets are currently manufactured and

launched by the United Launch Alliance.

Contents

 [hide]

1     Delta origins   

o 1.1      Early Delta flights   

2     Delta evolution   

o 2.1      Delta A   

o 2.2      Delta B   

o 2.3      Delta C   

o 2.4      Delta D   

o 2.5      Delta E   

o 2.6      Delta G   

o 2.7      Delta J   

o 2.8      Delta L   

o 2.9      Delta M   

o 2.10      Delta N   

o 2.11      'Super Six'   

o 2.12      Launch reliability   

3     Delta numbering system   

o 3.1      Delta 904   

o 3.2      Delta 1000-Series   

o 3.3      Delta 2000-Series   

o 3.4      Delta 3000-Series   

o 3.5      Delta 4000-Series   

o 3.6      Delta 5000-Series   

o 3.7      Delta II series   

3.7.1      Delta 6000-Series   

3.7.2      Delta 7000-Series   

3.7.3      Delta II Med-Lite   

3.7.4      Delta II Heavy   

o 3.8      Delta III (8000-Series)   

o 3.9      Delta IV (9000-series)   

4     Future development   

5     See also   

6     References   

7     External links   

[edit]Delta origins

Main article: Thor (rocket family)

See also: PGM-17 Thor

Delta rocket on display at the Goddard Space Flight Center in Maryland

The original Delta rockets used a modified version of the PGM-17 Thor, the first ballistic missile deployed

by the United States, as their first stage. The Thor had been designed in the mid-1950s to reach Moscow

from bases in Britain or similar allied nations, and the first wholly successful Thor launch had occurred in

September 1957. Subsequent satellite andspace probe flights soon followed, using a Thor first stage with

several different upper stages. The fourth upper stage used on the Thor was the Thor "Delta," delta being

the fourth letter of the Greek alphabet. Eventually the entire Thor-Delta launch vehicle came to be called

simply, "Delta."[1]

NASA intended Delta as "an interim general purpose vehicle" to be "used for communication,

meteorological, and scientific satellites and lunar probes during '60 and '61". The plan was to replace

Delta with other rocket designs when they came on-line. The Delta design emphasized reliability rather

than performance by replacing components which had caused problems on earlier Thor flights. NASA let

the original Delta contract to the Douglas Aircraft Company in April 1959 for 12 vehicles of this design:

Stage 1: Modified Thor IRBM with a Block I MB-3 engine producing 152,000 lbf (680 kN) thrust.

(LOX/RP1 turbopump, gimbal mounted engine, two verniers for roll control)

Stage 2: Modified Able. Pressure fed UDMH/nitric acid powered Aerojet AJ-10-118 engine producing

7,700 lbf (34 kN). This reliable engine cost $4 million to build and is still flying in modified form today.

Gas jet attitude control system.

Stage 3: Altair. A spin stabilized (via a turntable on top of the Able) at 100 rpm by two solid rocket

motors before separation. One ABL X-248 solid rocket motor provided 2,800 lbf (12 kN) of thrust for

28 seconds. The stage weighed 500 pounds (230 kg) and was largely constructed of wound

fiberglass.

These vehicles would be able to place 650 pounds (290 kg) into a 150 to 230 miles (240 to 370

km) LEO or 100 pounds (45 kg) into GTO. Eleven of the twelve initial Delta flights were successful. The

total project development and launch cost came to $43 million, $3 million over budget. An order for 14

more vehicles was let before 1962.

[edit]Early Delta flights

No.

Date Payload Site Outcome Remarks

1 May 13, 1960 Echo 1 CCAFS LC  failure Launch at 9:16 p.m. GMT. Good first stage. Second stage attitude 

17A control system failure. Vehicle destroyed.

2 August 12, 1960 Echo 1A successPayload placed into 1,035 miles (1,666 km), 47 degree inclination orbit.

3November 23, 1960

TIROS-2 success

4 March 25, 1961Explorer-10

success78 pounds (35 kg) payload placed into elliptical 138,000 miles (222,000 km) orbit.

5 July 12, 1961 TIROS-3 success

6 August 16, 1961Explorer-12

success Energetic Particle Explorers. EPE-A.[2] Highly elliptical orbit.

7February 8, 1962

TIROS-4 success

8 March 7, 1962 OSO-1 success Orbiting Solar Observatory. 345 miles (555 km), 33 degree orbit.

9 April 26, 1962 Ariel 1 successAriel 1 was later seriously damaged by the Starfish Prime nuclear test.

10 June 19, 1962 TIROS-5 success

11 July 10, 1962 Telstar 1 successAlso later damaged by the Starfish Prime high altitude nuclear event.

12September 18, 1962

TIROS-6 success

[edit]Delta evolution

Launch of the first Skynet satellite by Delta rocket in 1969 from Cape Canaveral

[edit]Delta A

Block II MB-3 engine, 170,000 lbf (760 kN) vs. 152,000 lbf (680 kN)

13. EPE2

14. EPE3

[edit]Delta B

Upgraded AJ10-118D upper stage—3-foot tank stretch, higher energy oxidizer, solid-state guidance

system.

Delta program goes from 'interim' to 'operational' status.

200 pounds (91 kg) to GTO.

15. 13 December 1962. Relay 1, second NASA communications satellite, NASA's first active one.

16. 13 February 1963. pad 17b. Syncom 1. Thiokol Star 13B solid rocket as apogee kick motor.

20. July 26, 1963. Syncom 2. Geosynchronous orbit, but inclined 33° due to the limited performance of

the Delta.

[edit]Delta C

Third stage Altair replaced with Altair 2—its engine having been developed as the ABL X-258 for the

Scout vehicle; 3 in (76 mm) longer, 10% heavier, but 65% more total thrust.

Sample mission: OSO-4

[edit]Delta D

Also known as Thrust Augmented Delta.

A Delta C with the Thrust Augmented Thor core plus three Castor 1 boosters.

25. 19 August 1964. Syncom 3, the first geostationary communications satellite.

30. 6 April 1965. Intelsat I

[edit]Delta E

Also known as Thrust Augmented Improved Delta.

1965.

100 pounds (45 kg) more to GTO than Delta D.

Castor 2 vs. Castor 1 boosters. Same thrust, longer duration.

MB-3 Block III core engine, 2,000 lbf (8.9 kN) more thrust.

AJ10-118E second stage widened from 2.75 feet (0.84 m) to 4.58 feet (1.40 m) diameter. Double

burn time.

Additional helium tanks allow for almost unlimited restarts.

Two available third stages: Altair 2 or FW-4D. The latter caused the Delta to be known as a Delta

E1.

New payload fairing from Agena.

First Delta E. 6 November 1965. Launched GEOS 1.

[edit]Delta G

Two stage Delta Es.

used for Biosatellite 1 and 2 flights.

1. 14 December 1966. Biosatellite 1.

2. 7 September 1967. Biosatellite 2

[edit]Delta J

Used larger Thiokol Star 37D motor as third stage.

4 July 1968. Explorer 38.

[edit]Delta L

Introduced Extended Long Tank first stage- 8 feet (2.4 m) diameter throughout.

FW-4d motor for third stage.

[edit]Delta M

Star 37D for stage 3.

[edit]Delta N

Two stage version of Delta M.

There were nine Delta N launch attempts from 1968 until 1972; eight were successful.[3]

[edit]'Super Six'

Delta M or Delta N with three extra strap ons.

1,000 pounds (450 kg) to GTO.

[edit]Launch reliability

From 1969 through 1978 (inclusive), Thor-Delta was NASA's most popular launcher, with 84 launch

attempts. (Scout was the second most used vehicle with 32 launches.)[4] NASA used it to launch its

own satellites, and also to launch satellites for other government agencies and foreign governments

on a cost reimbursable basis. Sixty-three of the satellites NASA attempted to launch were provided

by other parties. Out of the 84 attempts there were seven failures or partial failures (91.6%

successful).[5]

[edit]Delta numbering system

In 1972, McDonnell Douglas introduced a four-digit numbering system to replace the letter-naming

system. The new system could better accommodate the various changes and improvements to

Delta rockets (and avoided the problem of a rapidly depleting alphabet). It specified (1) the tank and

main engine type, (2) number of solid boosters, (3) second stage, and (4) third stage.[6]

Number

First Digit(First stage/boosters)

Second Digit(Number of boosters)

Third Digit(Second Stage)

Fourth Digit(Third stage)

Letter(Heavy

configuration)

0Long Tank ThorMB-3 engineCastor 2 SRBs

No SRBs Delta, with AJ-10 engines No third stageN/A

1 Extended Long Tank Thor N/A Delta, with TR-201 engines N/A

MB-3 engineCastor 2 SRBs

2Extended Long Tank ThorRS-27 engineCastor 2 SRBs

2 SRBs (or LRBs in the case of the Delta IVH)

Delta K, with AJ-10 enginesFW-4D (unflown)

3Extended Long Tank ThorRS-27 engineCastor 4 SRBs

3 SRBsDelta III cryogenic upper stage, RL-10B-2 engine

Star 37D

4Extended Long Tank ThorMB-3 engineCastor 4A SRBs

4 SRBsDelta IV 4m diameter cryogenic upper stage, RL-10B-2 engine

Star 37E

5Extended Long Tank ThorRS-27 engineCastor 4A SRBs

N/ADelta IV 5m diameter cryogenic upper stage, RL-10B-2 engine

Star 48B/PAM-D

6

Extra-Extended Long Tank ThorRS-27 engineCastor 4A SRBs

6 SRBs

N/A

Star 37FM

7

Extra-Extended Long Tank ThorRS-27A engineGEM 40 SRBs

N/A

N/A

GEM 46 SRBs

8

Strengthened Extra-Extended Long Tank ThorRS-27A engineGEM 46 SRBs

N/A

9Delta IV CBCRS-68 engine

9 SRBs2 additional CBC Parallel first stages

This numbering system was to have been phased out in favor of a new system that was introduced

in 2005.[7] In practice, this system has never been used.

Number

First Digit(First stage/boosters)

Second Digit(Number of boosters)

Third Digit(Second Stage)

Fourth Digit(Third stage)

Letter(Heavy

configuration)

0

N/A

No SRBs

N/A

No third stage

N/A

1 N/A

N/A

2

Extra-Extended Long Tank ThorRS-27A engineGEM 40 SRBs

2 SRBs (or LRBs in the case of the Delta IVH)

Delta K, with AJ-10 engines GEM 46 SRBs

3

Strengthened Extra-Extended Long Tank ThorRS-27A engineGEM 46 SRBs

3 SRBs N/A

4Delta IV CBCRS-68 engine

4 SRBsDelta IV 4m diameter cryogenic upper stage, RL-10B-2 engine

2 additional CBC Parallel first stages

5

N/A

N/A

Delta IV 5m diameter cryogenic upper stage, RL-10B-2 engine

Star 48B/PAM-D

N/A

6

N/A

Star 37FM

7

N/A8

9 9 SRBs

[edit]Delta 904

On July 23, 1972, the launch of Landsat 1 marked the first use of nine strap-on boosters, and the

new uprated second-stage engine (AJ 10-118F). This Thor-Delta model was designated the 904.[8]

[edit]Delta 1000-Series

Extended Long Tank with 8-foot-diameter (2.4 m) payload fairing; nicknamed "Straight-Eight".

Nine Castor II strap-on solid boosters.

The first successful 1000 series Thor-Delta launched Explorer 47 on September 22, 1972.[8]

[edit]Delta 2000-Series

Main article: Delta 2000

Features new Rocketdyne RS-27 main engine on Extended Long Tank. Same constant eight-foot

diameter.

Delta 2910 boosters were used to launch both Landsat 2 in 1975 and Landsat 3 in 1978.

A Delta 2914 was used 1978-04-07 to launch the Japanese BSE Broadcasting Satellite, also

known as "Yuri 1".[9]

[edit]Delta 3000-Series

Introduced upgraded Castor IV solid motors. Same first stage as 1000- and 2000-series.

Also introduced PAM (Payload Assist Module)/Star 48B solid-fueled kick motor. Later used as

Delta II third stage.

The Delta 3914 model was approved for launching U.S. government payloads in May 1976.[8]

[edit]Delta 4000-Series

Used old MB-3 main engine on Extended Long Tank with Castor IV motors.

Only launched two missions.

First use of a Delta-K second stage.

[edit]Delta 5000-Series

Featured upgraded Castor IVA motors on Extended Long Tank first stage with RS-27 main

engine.

Only launched one mission.

[edit]Delta II series

Main article: Delta II

The Delta II series consists of the retired Delta 6000, the active Delta 7000, and two variants (Lite

and Heavy) of the latter.

[edit]Delta 6000-Series

When in 1986 the Challenger accident demonstrated that Delta launches would continue, the Delta

II was developed.

Introduced Extra Extended Long Tank first stage. 12 additional feet provide more propellant.

Introduced Castor IVA boosters. Six ignite at takeoff, three ignite in flight.

[edit]Delta 7000-Series

Introduces RS-27A main engine, modified for efficiency at high altitude, at some cost to low-

altitude performance.

Introduces GEM-40 (Graphite-Epoxy Motor) solid boosters from Hercules (now Alliant). Besides

being longer, their lighter casings allow higher payload capability.

[edit]Delta II Med-Lite

A 7000-series with no third stage and fewer strap-ons (often three, sometimes four). Usually used

for small NASA missions.

[edit]Delta II Heavy

A Delta II 792X with the enlarged GEM-46 boosters from Delta III.

[edit]Delta III (8000-Series)

Main article: Delta III

A McDonnell Douglas/Boeing-developed program to keep pace with growing satellite masses:

The two upper stages, with low-performance fuels, were replaced with a single cryogenic stage,

improving performance and reducing recurring costs and pad labor. Engine was a single Pratt &

Whitney RL10, from the Centaur upper stage. The hydrogen fuel tank, 4 meters in diameter in

orange insulation, is exposed; the narrower oxygen tank and engine are covered until stage

ignition. Fuel tank contracted to Mitsubishi, and produced using technologies from Japanese H-

II launcher.

To keep the stack short and resistant to crosswinds, the first-stage kerosene tank was widened

and shortened, matching the upper-stage and fairing diameters.

Nine enlarged GEM-46 solid boosters attached. Three have thrust-vectoring nozzles.

Of the three Delta III flights, the first two were failures and the third carried only a dummy (inert)

payload.

[edit]Delta IV (9000-series)

Main article: Delta IV

As part of the Air Force's EELV (Evolved Expendable Launch Vehicle) program, McDonnell

Douglas/Boeing proposed Delta IV. As the program implies, many components and technologies

were borrowed from existing launchers. Both Boeing and Lockheed Martin were contracted to

produce their EELV designs. Delta IVs are produced in a new facility in Decatur, Alabama.

First stage changed to liquid hydrogen fuel. Tank technologies derived from Delta III upper stage,

but widened to 5 meters.

Kerosene engine replaced with Rocketdyne RS-68, the first new, large liquid-fueled rocket engine

designed in the US since the Space Shuttle Main Engine (SSME) in the '70s. Designed for low

cost; has lower chamber pressure and efficiency than the SSME, and a much simpler nozzle.

Thrust chamber and upper nozzle is a channel-wall design, pioneered by Soviet engines. Lower

nozzle is ablatively cooled.

Second stage and fairing taken from the Delta III in smaller (Delta IV Medium) models; widened

to 5 meters in Medium+ and Heavy models.

Medium+ models have two or four GEM-60 60-inch diameter solid boosters.

Revised plumbing and electric circuits eliminate need for a launch tower.

The first stage is referred to as a common booster core (CBC); a Delta IV Heavy attaches two extra

CBCs as boosters.

[edit]Future development