 Titan IV-B with 2 SRMU boosters | |
| Country of origin |  United States |
|---|---|
| Designer | Hercules |
| Manufacturer | Alliant Techsystems |
| Application | Solid rocket booster |
| Predecessor | UA1207 |
| Status | Retired |
| Solid-fuel motor | |
| Propellant | HTPB |
| Casing | Composite |
| Configuration | |
| Nozzle ratio | 15.7 |
| Performance | |
| Thrust | 6.41 MN (1,440,502 lbf) average |
| Chamber pressure | 859.5 psi (5,926 kPa) |
| Specific impulse, vacuum | 285.6 s (2.801 km/s) |
| Specific impulse, sea-level | 251.4 s (2.465 km/s) |
| Burn time | 135.7s |
| Thrust vectoring | 6 degrees |
| Dimensions | |
| Length | 34.26 m (1349 in) |
| Diameter | 3.2m (126 in) |
| Empty mass | 80,611 lb (36,565 kg) |
The Solid Rocket Motor Upgrade (SRMU) was a solid rocket motor that was used as a booster on the Titan IVB launch vehicle. Developed by Hercules (later ATK), it was intended to be a high-performance, low-cost upgrade to the UA1207 boosters previously used on Titan IV. Wound from carbon-fibre-reinforced polymer and burning a hydroxyl-terminated polybutadiene-bound ammonium perchlorate composite propellant, it was an ambitious upgrade building on Hercules' experience developing a filament-wound case for the Space Shuttle SRB. Originally intended to fly in 1990, it instead first flew in 1997 due to a protracted development and lack of demand. The SRMU performed successfully on all of its flights.