According to this answer, turning on Apollo 13's Service Module Propulsion System was considered risky since ground control ditn't know if it was damages in the explosion

Perform a PC+2 hour abort burn with the Service Module Propulsion System for a landing at 118+00 in the Pacific Ocean. This option was rejected unanimously as being too risky since no data was available as to the structural integrity of the Service Module. This option was put into the category of "last ditch".

Did NASA ever find out if the engine was damaged that bad that it would have exploded had it been turned on?

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    $\begingroup$ The NASA could not investigate the Service Module and its engine, the SM was destroyed during reentry like every other SM of the other Apollo missions. Only photo were made of the SM after separation of the CM. $\endgroup$
    – Uwe
    Feb 8, 2018 at 19:52

1 Answer 1


It is believe that it was. The photographs taken as the SM was ejected show a slight deformation of the bell. In addition, the explosion likely put pressure on the interior section of the service module where fluids were passed. There is a very high likelihood that something was damaged.

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    $\begingroup$ In fact, the irregular shape of the bell could have had difficult to predict effects on the thrust which maybe could or maybe could not have been compensated for. At the very least one would probably (I'm guessing here) choose to burn the SPS for longer at lower power rather than more briefly at higher power so as to minimize a catastrophic structural or engine failure. Oscillations as a result of irregular thrust because of a weakened and deformed engine bell being one of the concerns. This is of course if the other options are exhausted (which they were not). $\endgroup$ Aug 23, 2018 at 23:35
  • $\begingroup$ @KenClement: Also, a lower-power burn would have made it easier to maintain directional control using the RCS jets in the event that damage to the SPS bell caused some degree of asymmetry in the thrust it produced. $\endgroup$
    – Vikki
    Apr 24, 2019 at 23:31
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    $\begingroup$ The SPS wasn't throttleable. $\endgroup$ Mar 19, 2020 at 17:10

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