MA-5A was an American liquid fueled rocket stage. It was manufactured by Lockheed Martin for use on the Atlas II rocket, derived from the MA-5 used on the Atlas I.
| Manufacturer | Lockheed Martin |
|---|---|
| Country of origin | United States |
| Used on | Atlas II |
| General characteristics | |
| Height | 3.43 metres (11.3 ft) |
| Diameter | 3.05 metres (10.0 ft) |
| Gross mass | 4,187 kilograms (9,231 lb) |
| Derived from | MA-5 |
| MA-5A | |
| Powered by | 2 RS-56-OBA |
| Maximum thrust | 2,100 kN (470,000 lbf) |
| Specific impulse | 296 seconds (2.90 km/s) |
| Propellant | LOX/RP-1 |
| Launch history | |
| Status | Retired |
Design
editMA-5A functioned as the "half stage" in the Atlas's "stage-and-a-half" design, meaning they functioned as a booster attached to a central sustainer core, but did not include their own fuel tanks. Instead, fuel was drained out of the tanks of the sustainer core, until partway through the launch the booster segment was jettisoned. Similar to the booster segments on previous Atlas rockets, MA-5A consisted of a thrust structure with attachment points and fuel lines for two RS-56-OBA rocket engines, each contained in a nacelle for aerodynamic reasons.[1] The middle was left empty to accommodate the RS-56-OSA engine of the sustainer stage. The two booster engines shared a common gas generator, but separate turbopumps, combustion chambers, and other hardware.[2] The stage also contains ten bottles of pressurized helium, used to drive the pneumatics for the engines and for tank pressurization. On the Atlas IIAS configuration, MA-5A also featured attachment points for four Castor 4A solid rocket boosters.[1][3]
MA-5A was based on the design of the previous MA-5 stage, used on Atlas I. The main difference between the two designs was the replacement of the MA-5's two LR-89-7 engines with RS-56-OSAs.[4]
References
edit- ^ a b "Atlas Launch System Payload Planner's Guide" (PDF). Lockheed Martin. Archived from the original (PDF) on 21 April 2015. Retrieved 9 January 2016.
- ^ "Atlas IIA(S) Data Sheet". Space Launch Report. Archived from the original on August 13, 2016. Retrieved 9 January 2015.
{{cite web}}: CS1 maint: unfit URL (link) - ^ "Atlas IIAS". Astronautix. Archived from the original on May 1, 2002. Retrieved 9 January 2016.
- ^ "MA-5A". Astronautix. Archived from the original on March 19, 2002. Retrieved 10 January 2016.