Environmental Control System (CSM)

This section provides step-by-step examples and instructions how to use the Environmental Control System (ECS). Hopefully this will help users to get a better understanding and feeling how to work with the spacecraft systems. In these procedures it is assumed that the spacecraft is in a "stable condition" without flying manoeuvers with ECS in "flight configuration", for example during Trans Lunar Coast and you can use time acceleration up to 1000 so that all of the internal systems have reasonable reaction times.

ECS monitoring check

This is the part of the original Apollo documentation used for regular checking the most important ECS components. These procedures are from the Apollo-Soyuz test project Operations handbook reference issue (see below).

Suit compressor shutdown and restart

During normal operations suit compressor 1 is turned on in order to drive the suit atmosphere regeneration systems, which remove CO2, water and other unwanted substances. Suit compressor 2 is redundant and turned off. The following procedure demonstrates the necessity of the suit compressor.

• At the beginning the suit compressor should work normally so the SUIT COMPRESSOR 1 switch is in AC1 position (that means on) and the SUIT COMPRESSOR 2 switch is in OFF position. The SUIT COMPR ΔP meter shows 0.3 - 0.4 psi, the PART PRESS CO2 meter shows appox. 2 mmHg, which is far below the CO2 PP HI value of 7.6 mmHg, so the suit compressor is working properly.

• Switch the SUIT COMPRESSOR 1 switch to OFF (center position). The SUIT COMPR ΔP meter drops to 0 psi within a few seconds indicating that the compressors stopped working. You get a SUIT COMPRESSOR alarm, push the MASTER ALARM pushbutton/light to turn off the alarm. The PART PRESS CO2 meter begins to increase.

• After about 10 minutes the PART PRESS CO2 meter shows a pressure of 7.6 mmHg or higher, the suit atmosphere gets seriously poisoned. You get a CO2 PP HI alarm, push the MASTER ALARM pushbutton/light to turn off the alarm. The O2 FLOW meter shows a decreased flow because the suit circuit is no longer supplied with fresh oxygen.

• Switch the SUIT COMPRESSOR 1 switch back to AC1. The SUIT COMPR ΔP meter goes back to 0.3 - 0.4 psi, the SUIT COMPRESSOR alarm goes away, the PART PRESS CO2 meter slowly begins to decrease.

• After a few minutes the CO2 PP HI alarm goes away. After about 1 hour the PART PRESS CO2 meter should show approx. 2 mmHg and is normal again.