Apollo SM SPS engine

[darian]

Could the SM SPS engine be fired manually in orbit. I mean without the AGC. Like how on Apollo 13 the crew fired the LM descent in orbit manually to get on proper course with the Earth.

 

[Quick_Nick]

I believe it was possible, as it is in NASSP, to setup the systems so that you can flip a switch or press a button to engage the SPS engine. However, in real life you would first have to translate forward for a while since I believe the engine is gravity-fed. (I think the SIVB is also gravity-fed) I believe the LM engines are pressurized though and shouldn't need that little push.

 

[Deke]

I would assume it could incase the AGC should fail during flight...

 

[tblaxland]

Could the SM SPS engine be fired manually in orbit. I mean without the AGC. Like how on Apollo 13 the crew fired the LM descent in orbit manually to get on proper course with the Earth.

Yes, it could. The NASSP wiki gives a good descripition of how it would work:
http://nassp.sourceforge.net/wiki/SPS#Engine_thrust_on.2Foff_logic

In essence, throw a few switches and you get thrust :speakcool: The SPS thrust vectoring could be controlled manually also.

More information can be found in the SPS section of the Apollo Operations Handbook:
http://history.nasa.gov/afj/aoh/aoh-v1-2-04-sps.pdf

 

[darian]

Nice stuff, thanks for info.