Orbital Maneuvering System
The Orbital Maneuvering System ( OMS ) formed the drive and with the Reaction Control System (RCS) the attitude control of the space shuttles after the main engines were switched off and the US space shuttle had reached its orbit.
The OMS consisted of two rocket engines , which were housed in two independent housings at the stern. The steering jets were quite simple in design and used hypergolic fuel, which consists of two components that ignite when touched. This eliminates the need for an ignition system, which increases the reliability of the system and reduces weight.
The OMS thrusters were needed to reach orbit . They were also responsible for changes in the height of the runway and for carrying out rendezvous maneuvers. The OMS was also used to slow down the orbiter necessary to leave orbit at the end of a mission ( Deorbit Burn ).
The OMS engines burned monomethylhydrazine and nitrous tetroxide and provided a thrust of 27 kilonewtons and a specific impulse of 313 seconds. They were reusable for 100 missions and could be detonated a thousand times. The total burn time was 15 hours. The shuttle carried propellant for a speed change of approximately 300 m / s. The OMS engine was movably mounted and could be swiveled in the vertical axis by ± 7 degrees and in the plane of the transverse axis by ± 8 degrees. This made it possible to align the thrust vector with the center of gravity of the orbiter. Otherwise the orbiter would have rotated undesirably.
The fuel from the OMS tanks could be used to power the rear RCS jets as both systems used the same combination of fuel. This maneuver is called OMS-to-RCS interconnect . It was not possible to use the RCS fuel for the OMS nozzles because the RCS tanks were much smaller.
In addition, the fuel from one OMS pod could be used to operate the other, which is known as crossfeed . A filling of one fuel tank by the other was not intended, this was prevented by valves.
Further uses for Orion
In 2015 it was announced that NASA is making one of the OMS available to ESA for further use in the Orion service module. The module was developed by ESA on the basis of the Automated Transfer Vehicle (ATV) and is intended for the flight to the moon ( Artemis 1 ) of this spaceship. This OMS had previously been used in 19 shuttle missions. In 2017, the use of up to four such units was negotiated. The first completed service module was delivered by ESA to NASA at the end of 2018.
Web links
- NASA: NSTS 1988 News Reference Manual: Orbital Maneuvering System (English)
Individual evidence
- ↑ NASA Gears Up to Test Orion's Powerhouse. June 17, 2015, accessed January 28, 2019 .
- ↑ ESA deal hinges on what Trump does with NASA's human spaceflight plans. February 13, 2017, accessed January 28, 2019 .