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  Apollo CM lifetime after SM jettison?

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Author Topic:   Apollo CM lifetime after SM jettison?
John Charles
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Posts: 342
From: Houston, Texas, USA
Registered: Jun 2004

posted 10-15-2018 03:46 PM     Click Here to See the Profile for John Charles     Edit/Delete Message   Reply w/Quote
Does anyone have a good reference or source of info on how long the Apollo command module could support life after service module jettison (presumably just a few hours)?

I am having a lot of trouble finding info on CM oxygen supply, battery capacity, etc. Any help appreciated!

oly
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Posts: 971
From: Perth, Western Australia
Registered: Apr 2015

posted 10-15-2018 08:53 PM     Click Here to See the Profile for oly   Click Here to Email oly     Edit/Delete Message   Reply w/Quote
This is dependent upon some variables, including if the command modules batteries were fully charged prior to SM jettison.

From the Apollo 11 Flight Plan, Section 5: Consumables:

Three entry and postlanding batteries were considered available to supply the total spacecraft power required for entry, parachute descent, and postlanding time. Each battery was assumed to have a 40 A-h capacity until splashdown, at which time the capacity was uprated to 45 A-h.

The EPS oxygen consumption rate (lb/hr) = 7.936 x H2

So the battery life from full charge would depend upon how much power was being consumed (how much equipment was turned on).

The original design specifications from the “CSM Technical Specification (Block II) Dec 1964 (SID 64-1344):

The CSM shall be habitable for 48 hours and retrievable for 7 days following a water landing.

Design Mission Reference
Entry and landing .40 hr

Consumable Design Mission

  • Pre-entry: 0.08 hr
  • Entry: 0.05 hr
  • Recovery: 0.17
Also, should the command module experience an oxygen or ventilation failure post splashdown, the CSM checklist (Apollo 15) identifies that the crew must egress the CM within 2.5 hours post landing. At the end of this manual is also a low power checklist to draw out battery life.

Finally, all you ever wanted to know about the Apollo batteries. The command module entry battery was switched on EI-30 minutes.

All times are CT (US)

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