Delta III

Summary

Delta III was an expendable launch vehicle made by Boeing. The first Delta III launch was on August 26, 1998.[4] Of its three flights, the first two were failures, and the third, though declared successful, reached the low end of its targeted orbit range and carried only a dummy (inert) payload. The Delta III could deliver up to 8,400 pounds (3,800 kilograms) to geostationary transfer orbit, twice the payload of its predecessor, the Delta II.[1] Under the four-digit designation system from earlier Delta rockets, the Delta III is classified as the Delta 8930.

Delta III
Delta III.svg
A Delta III rocket diagram
FunctionOrbital launch vehicle
ManufacturerBoeing
(design, manufacturing and assembly)

Mitsubishi Heavy Industries
(extended kerosene tank and H-IIA-based upper stage manufacturing)
Country of originUnited States
Size
Height35 m (115 ft)
Diameter4 m (13 ft)
Mass301,450 kg (664,580 lb)
Stages2
Capacity
Payload to LEO
Mass8,290 kg (18,280 lb)[1]
Payload to GTO
Mass3,810 kg (8,400 lb)[1]
Associated rockets
FamilyDelta
Launch history
StatusRetired
Launch sitesSLC-17, Cape Canaveral
Total launches3
Success(es)0
Failure(s)2
Partial failure(s)1
First flightAugust 26, 1998
Last flightAugust 23, 2000
Boosters
No. boosters9 GEM 46
Maximum thrust628.3 kN (141,200 lbf)
Specific impulse273 seconds (2.68 km/s)
Burn time75 seconds
PropellantHTPB bound APCP
First stage
Powered by1 Rocketdyne RS-27A
Maximum thrust1,085.79 kN (244,100 lbf)
Specific impulse254 seconds (2.49 km/s)
Burn time260 seconds[2]
PropellantLOX/RP-1
Second stage
Powered by1 Pratt & Whitney RL10B
Maximum thrust110.03 kN (24,740 lbf)
Specific impulse462 seconds (4.53 km/s)[3]
Burn time700 seconds[2]
PropellantLOX/LH2
Third stage (Optional)
Powered by1 Thiokol Star 48B
Maximum thrust66.723 kN (15,000 lbf)
Specific impulse286 seconds (2.80 km/s)
Burn time87 seconds
PropellantHTPB

DescriptionEdit

 
A Delta III DCSS upper stage undergoing testing at Plum Brook Field Station in January 1998

Like the Delta II, the first stage of the Delta III burned kerosene and liquid oxygen and was powered by one Rocketdyne RS-27A main engine with two vernier engines for roll control.[5] While the propellant load and gross mass of the stage were nearly identical to the Delta II, the diameter of the kerosene tank was increased from 2.4 meters to 4 meters. This reduced the overall length of the vehicle and allowed the Delta III to use the same launch facilities as the Delta II with only minor modifications.[1] First stage thrust was augmented by nine GEM 46 solid rocket boosters, sometimes referred to as GEM LDXL (Large Diameter Extended Length). These were 14.7 meters in length, 1.2 m (46 inches) in diameter, and had a mass of 19 metric tons each, about six metric tons more than the Delta II's standard GEM 40 motors. Six were ignited on the launch pad, while the remaining three were ignited just before burnout and separation of the ground-lit boosters. To maintain steering authority, three of the boosters had vectoring nozzles.[1] GEM 46 boosters would later find use on the Delta II, leading to the Delta II Heavy.

The second stage of the Delta III was the newly developed Delta Cryogenic Second Stage (DCSS), which burned liquid hydrogen and liquid oxygen. The liquid hydrogen tank was 4 meters in diameter, while the separate liquid oxygen tank was 2.4 meters in diameter. This stage offered significantly better performance than the Delta II's second stage, the Delta-K, which burns hypergolic propellants.[1] The DCSS was powered by a Pratt & Whitney RL10B-2 engine, derived from the RL10 powering the Centaur upper stage but featuring electromechanical actuators for gimbal control and an extending nozzle for increased specific impulse.[5] After Delta III's retirement, this stage was modified for use as the Delta IV's second stage.[6] The payload fairing was a new composite design, matching the upper stage hydrogen tank at 4 meters diameter and allowing larger payloads than the Delta II's 9.5 or 10 foot fairing. Payload to GTO (Geostationary-Transfer Orbit) was doubled versus the Delta II. However, the consecutive failures of the initial Delta IIIs, combined with the more advanced Delta IV program and the continuing success of the Delta II, left the Delta III as an interim vehicle.[3]

LaunchesEdit

Flight Number Date / time (UTC) Rocket
Configuration
Launch site Payload Payload mass Orbit Customer Launch
outcome
1 August 27, 1998
01:17
Delta 3 8930 CCAFS SLC-17B Galaxy 10 1,543 pounds (700 kilograms) GTO PanAmSat / Intelsat Failure
Maiden flight of Delta 3 8930, Destroyed by range safety after control problems and depletion of hydraulic fluid, Communications satellite.
2 May 5, 1999
01:00
Delta 3 8930 CCAFS SLC-17B Orion 3 9,480 pounds (4,300 kilograms) GTO Loral Failure
Second stage engine failure. Payload placed into LEO, Communications satellite.
3 August 23, 2000
11:05
Delta 3 8930 CCAFS SLC-17B DM-F3 9,663 pounds (4,383 kilograms) GTO US Air Force Partial failure[7]
Reached lower than planned orbit, final flight of Delta 3 8930, Demosat. See alsoEdit

ReferencesEdit

  1. ^ a b c d e f "Delta III Launch Vehicle". 2001. Archived from the original on November 14, 2001.
  2. ^ a b "Delta III Payload Planner's Guide" (PDF). Archived from the original (PDF) on 19 November 2001.
  3. ^ a b "Delta III Data Sheet". Space Launch Report. Retrieved 26 July 2014.
  4. ^ "Delta III Takes a Dip". WIRED. Retrieved 2018-10-24.
  5. ^ a b "Delta 3". Astronautix. Archived from the original on November 12, 2013. Retrieved January 5, 2015.
  6. ^ "Delta 3 Rocket Falls Short, but Still a Success Boeing Says". SpaceFlightNow. August 24, 2000.
  7. ^ "Delta 3 rocket falls short but still a success, Boeing says". Spaceflight Now. August 24, 2000.

External linksEdit

  • History of the Delta Launch Vehicle
  • Spaceflight Now article 8/21/2000