Titan IIIE

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Titan IIIE
Titan 3E Centaur launches Voyager 2.jpg
Launch of a Titan IIIE with Voyager 2
Function Expendable launch system
Manufacturer Martin Marietta
Country of origin  United States
Size
Height 48 metres (157 ft)
Diameter 3.05 metres (10.0 ft)
Mass 632,970 kilograms (1,395,460 lb)
Stages 3-4
Capacity
Payload to
LEO
15,400 kilograms (34,000 lb)
Payload to
Heliocentric orbit (TMI)
3,700 kilograms (8,200 lb)
Associated rockets
Family Titan
Launch history
Status Retired
Launch sites LC-41, Cape Canaveral
Total launches 7
Successes 6
Failures 1
First flight 11 February 1974
Last flight 5 September 1977
Notable payloads Voyager (1 / 2)
Viking (1 / 2)
Helios
Boosters (Stage 0) - UA1205
No boosters Two
Engines 1 solid
Thrust 5,849 kilonewtons (1,315,000 lbf)
Specific impulse 263 sec
Burn time 115 seconds
Fuel Solid
First Stage
Engines 2 LR87-11
Thrust 2,340 kilonewtons (530,000 lbf)
Specific impulse 302 sec
Burn time 147 seconds
Fuel A-50/N2O4
Second Stage
Engines 1 LR91-11
Thrust 454 kilonewtons (102,000 lbf)
Specific impulse 316 sec
Burn time 205 seconds
Fuel A-50/N2O4
Third Stage - Centaur-D
Engines 2 RL-10A-3
Thrust 131 kilonewtons (29,000 lbf)
Specific impulse 444 sec
Burn time 470 seconds
Fuel LH2/LOX
Fourth Stage (optional) - Star-37E
Engines 1 solid
Thrust 68 kilonewtons (15,000 lbf)
Specific impulse 284 sec
Burn time 42 seconds
Fuel Solid

The Titan IIIE or Titan 3E, also known as Titan III-Centaur was an American expendable launch system, launched seven times between 1974 and 1977.[1] It was used to launch several high-profile NASA missions, including the Voyager and Viking planetary probes, and the joint West German-US Helios spacecraft.

The Titan IIIE was the largest and most powerful US launch vehicle yet developed for the unmanned space program. While NASA had originally considered using the Transtage, the reliability of it was in doubt, so they went with the proven Centaur. However, Centaur had been designed for the very different Atlas vehicle and a number of changes were needed to accommodate it to the Titan, the biggest being encasing the stage in a large shroud that bulged outward because of the different diameter of the two. There was also the concern that the Titan might generate too much heat because of using hypergolic propellants stored at room temperature and solid rocket motors, and that the Centaur's super-cooled LH2 would get warm enough to turn back into gas. Extra insulation was thus added inside the payload shroud to keep things cool. The Centaur also contained the guidance computer for the entire launch vehicle. A four-stage configuration, with an additional upper stage, a Star-37E, was also available, and was used for the two Helios launches.[2] Star-37E stages were also used on the two Voyager launches, but were considered to be part of the payload rather than the rocket.[3]

All seven launches were conducted from Launch Complex 41 at Cape Canaveral.

The first Titan IIIE launch occurred on February 11, 1974. Original plans were to fly a boilerplate Viking probe, but NASA decided to add a secondary payload: a test satellite called SPHINX (Space Plasma High Voltage Interaction Experiment) which was intended to test the operation of high voltage power supplies in the vacuum of space. The mission was unsuccessful; while the Titan booster performed normally, the Centaur's engines failed to start. Ground controllers waited and issued a manual start command 1:10 seconds later, but still nothing happened. 12 minutes after liftoff, the range safety destruct command was sent from a radar station in Antigua. The cause of the failure was unclear and thought to be either a propellant leak that froze something or a piece of debris obstructing a fuel line, and the only solution to prevent this situation from happening again was performing prelaunch checks of the Centaur's turbopumps to make sure they rotated properly. It took nearly four years to discover the real culprit, which was a workman at Convair who had improperly installed a rivet inside the LOX tank. The rivet then came loose during launch and lodged in one of the boost pumps.[4]Despite the failure, at least one important goal was accomplished in that the bulging Centaur payload shroud was proven to be aerodynamically stable in flight and had jettisoned properly and on schedule. All subsequent launches were successful.

Launch History[edit]

Date/Time (GMT) S/N Payload Outcome Remarks
Titan Centaur
11 February 1974
13:48:02
23E-1 TC-1 Sphinx Failure Centaur LOX turbopump malfunction. RSO destruct at T+742 seconds.
10 December 1974
07:11:02
23E-2 TC-2 Helios-1 Successful
20 August 1975
21:22:00
23E-4 TC-4 Viking 1 Successful
9 September 1975
18:39:00
23E-3 TC-3 Viking 2 Successful
15 January 1976
05:34:00
23E-5 TC-5 Helios-2 Successful
20 August 1977
14:29:44
23E-7 TC-7 Voyager 2 Successful
5 September 1977
12:56:01
23E-6 TC-6 Voyager 1 Successful

Design[edit]

Schematics of Titan IIIE with two solid rocket motors (Stage 0) and the Titan III core vehicle Stages I and II


References[edit]

  1. ^ Wade, Mark. "Titan". Encyclopedia Astronautica. Retrieved 2009-01-25. 
  2. ^ Krebs, Gunter. "Titan-3E Centaur-D1T Star-37E". Gunter's Space Page. Retrieved 2009-01-25. 
  3. ^ Krebs, Gunter. "Titan-3E Centaur-D1T". Gunter's Space Page. Retrieved 2009-01-25. 
  4. ^ Dawson, Virginia; Bowles, Mark (2004). Taming Liquid Hydrogen: The Centaur Upper Stage Rocket 1958-2002. NASA. p. 145–146. 

External links[edit]

Media related to Titan IIIE at Wikimedia Commons