Initially Centauri was using Apollo CSM as escape pods on its very early stations, such as Station XST. Apollo CSM's were hard to maintain with the small target area for dropping cargo, such as O2 and CO2 scrubbers. The service module was also fairly bulky compared to the space for human occupants.
Variations like the Apollo + Small Tug were tried on ships like the Joyceln E. This reduced the footprint of the escape pod, but it still suffered from the maintenance problems of the Apollo CSMs.
The next step was the Orion II. This was the same concept as the Apollo + Tug, but scaled up to use an Orion CSM and Medium Tug. The maintenance and performance was good, however something about the look of the vehicle was off. The large tug made the vehicle feel bulky. Because of this visual concern, the Orion II was superseded by the Orion III which used the smaller Heavy Tug.
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| From left to right: Apollo, Orion II and Orion III |
Only two Orion IIs were put into trial service. Both were replaced with Orion IIIs prior to the host ships being launched.
