Delta (rocket family)

Delta Family
The Delta rocket family.
Role Expendable launch system with various applications
Manufacturer United Launch Alliance
Introduction 1960
Status active

Delta is a versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. There have been more than 300 Delta rockets launched, with a 95 percent 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

Delta origins

The original Delta rockets used a modified version of the PGM-17 Thor, the first ballistic missile deployed by the United States Air Force, 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 and space 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:

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.

Early Delta flights

No. Date Payload Site Outcome Remarks
1 May 13, 1960 Echo 1 CCAFS LC 17A failure Launch at 9:16 p.m. GMT. Good first stage. Second stage attitude control system failure. Vehicle destroyed.
2 August 12, 1960 Echo 1A success Payload placed into 1,035 miles (1,666 km), 47 degree inclination orbit.
3 November 23, 1960 TIROS-2 success
4 March 25, 1961 Explorer-10 success 78 pounds (35 kg) payload placed into elliptical 138,000 miles (222,000 km) orbit.
5 July 12, 1961 TIROS-3 success
6 August 16, 1961 Explorer-12 success Energetic Particle Explorers. EPE-A.[2] Highly elliptical orbit.
7 February 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 success Ariel 1 was later seriously damaged by the Starfish Prime nuclear test.
10 June 19, 1962 TIROS-5 success
11 July 10, 1962 Telstar 1 success Also later damaged by the Starfish Prime high altitude nuclear event.
12 September 18, 1962 TIROS-6 success

Delta evolution

Delta A

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

13. EPE2
14. EPE3

Delta B

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

Delta C

Sample mission: OSO-4

Delta D

25. 19 August 1964. Syncom 3, the first geostationary communications satellite
30. 6 April 1965. Intelsat I

Delta E

First Delta E. 6 November 1965; Launched GEOS 1

Delta G

1. 14 December 1966. Biosatellite 1
2. 7 September 1967. Biosatellite 2

Delta J

4 July 1968; Explorer 38

Delta L

Delta M

Delta N

'Super Six'

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]

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)
0 Long Tank Thor
MB-3 engine
Castor 2 SRBs
No SRBs Delta, with AJ-10 engines No third stage N/A
1 Extended Long Tank Thor
MB-3 engine
Castor 2 SRBs
N/A Delta, with TR-201 engines N/A
2 Extended Long Tank Thor
RS-27 engine
Castor 2 SRBs
2 SRBs (or LRBs in the case of the Delta IVH) Delta K, with AJ-10 engines FW-4D (unflown)
3 Extended Long Tank Thor
RS-27 engine
Castor 4 SRBs
3 SRBs Delta III cryogenic upper stage, RL-10B-2 engine Star 37D
4 Extended Long Tank Thor
MB-3 engine
Castor 4A SRBs
4 SRBs Delta IV 4m diameter cryogenic upper stage, RL-10B-2 engine Star 37E
5 Extended Long Tank Thor
RS-27 engine
Castor 4A SRBs
N/A Delta IV 5m diameter cryogenic upper stage, RL-10B-2 engine Star 48B/PAM-D
6 Extra-Extended Long Tank Thor
RS-27 engine
Castor 4A SRBs
6 SRBs N/A Star 37FM
7 Extra-Extended Long Tank Thor
RS-27A engine
GEM 40 SRBs
N/A N/A GEM 46 SRBs
8 Strengthened Extra-Extended Long Tank Thor
RS-27A engine
GEM 46 SRBs
N/A
9 Delta IV CBC
RS-68 engine
9 SRBs 2 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 was 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 Thor
RS-27A engine
GEM 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 Thor
RS-27A engine
GEM 46 SRBs
3 SRBs N/A
4 Delta IV CBC
RS-68 engine
4 SRBs Delta 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/A
8
9 9 SRBs

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]

Delta 1000-Series

Delta 2000-Series

Delta 3000-Series

Delta 4000-Series

Delta 5000-Series

Delta II series

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

Delta 6000-Series

When in 1986 the Challenger accident demonstrated that Delta launches would continue, the Delta II was developed.

Delta 7000-Series

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.

Delta II Heavy

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

Delta III (8000-Series)

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

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

Delta IV (9000-series)

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.

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

Future development

Currently development is focused on the Delta IV Heavy, which uses three Common Booster Cores to lift higher masses to orbit and escape velocity.

See also

References

External links