|astronautix.com||Apollo LEM as backup for the service propulsion system|
In order to use the LEM as a backup for the service propulsion system (SPS) to abort the mission during the 15-hour period following translunar injection, Grumman informed North American that some redesign of the spacecraft's helium system would likely be required. This information prompted North American designers to undertake their own analysis of the situation. On the basis of their own findings, this latter group disagreed with the LEM manufacturer.
NAA's analysis indicated: