Peter B
2002-Jan-02, 05:52 AM
I was browsing through the Apollo 15 Flight Journal on NASA’s website. Within this impressively long and detailed document I happened across the following quote, which seems to be relevant to an earlier (now locked) thread about a spacecraft in sunlight. It related to the last few hours of the flight when the Command Module had separated from the Service Module, yet had most of its systems switched on in preparation for re-entry.
“During these preparations, virtually all of the Command Module systems are powered up. The heat generated by these systems is readily handled by the thermal control systems (part of the Environmental Control System) within the Service Module. Under moderate power loads, the heat from the Command and Service module systems is absorbed by a water-glycol solution (not unlike that which is found in the radiator of an automobile) and is rejected to space through a series of radiators located on the upper panels of the Service Module. A water evaporator system, similar in principle to that of the PLSS sublimators (the Portable Life Support System, worn by the crews on the lunar surface), is also available to remove larger amounts of heat.
“Unfortunately, once the Command and Service Modules separate prior to entry, the elaborate heat dissipation systems used by the Command Module float away with the rest of Service Module. A special provision must be made, therefore, to manage the heat generated within the Command Module during the 30 minutes between separation and splashdown.”
“During these preparations, virtually all of the Command Module systems are powered up. The heat generated by these systems is readily handled by the thermal control systems (part of the Environmental Control System) within the Service Module. Under moderate power loads, the heat from the Command and Service module systems is absorbed by a water-glycol solution (not unlike that which is found in the radiator of an automobile) and is rejected to space through a series of radiators located on the upper panels of the Service Module. A water evaporator system, similar in principle to that of the PLSS sublimators (the Portable Life Support System, worn by the crews on the lunar surface), is also available to remove larger amounts of heat.
“Unfortunately, once the Command and Service Modules separate prior to entry, the elaborate heat dissipation systems used by the Command Module float away with the rest of Service Module. A special provision must be made, therefore, to manage the heat generated within the Command Module during the 30 minutes between separation and splashdown.”