Inertial Upper Stage

Inertial Upper Stage

Painting of Ulysses deploying from the Space Shuttle
Manufacturer	Boeing United Technologies
Country of origin	United States
Used on	Space Shuttle Titan 34D Titan IV
General characteristics
Height	5.2 m (17 ft)[1]
Diameter	2.8 m (9 ft 2 in)
Gross mass	14,700 kg (32,400 lb)
Associated stages
Derivatives	TOS
Launch history
Status	Retired
Total launches	24
Successes (stage only)	21
Failed	2
Lower stage failed	1
First flight	30 October 1982
Last flight	14 February 2004[2]
Stage 1
Height	3.15 m (10.3 ft)[3]
Diameter	2.34 m (7 ft 8 in)[3]
Gross mass	10,400 kg (22,900 lb)[3]
Propellant mass	9,700 kg (21,400 lb)[1]
Powered by	Orbus-21
Maximum thrust	190 kN (43,000 lbf)[1]
Specific impulse	295.5 s[3]
Burn time	up to 150 seconds[1]
Propellant	Solid
Stage 2
Height	1.98 m (6 ft 6 in)[3]
Diameter	1.60 m (5 ft 3 in)[3]
Gross mass	3,000 kg (6,600 lb)
Propellant mass	2,700 kg (6,000 lb)[1]
Powered by	Orbus-6
Maximum thrust	80 kN (18,000 lbf)[1]
Specific impulse	289.1 s[3]
Propellant	Solid

The Inertial Upper Stage (IUS), originally designated the Interim Upper Stage, was a two-stage, solid-fueled space launch system developed by Boeing for the United States Air Force beginning in 1976^[4] for raising payloads from low Earth orbit to higher orbits or interplanetary trajectories following launch aboard a Titan 34D or Titan IV rocket as its upper stage, or from the payload bay of the Space Shuttle as a space tug.