For a manned space station in low lunar orbit, design a thermal control system to maintain all of the avionics components within an acceptable temperature range and simultaneously provide a healthy, comfortable environment for the astronauts during the entire mission.
Background:
NASA is planning to study the concept of placing a Space Station in Low
Lunar Orbit (LLO). LLO is a challenging thermal environment and, as such,
the Thermal Control System (TCS) design is complicated. There are a number
of thermal control system design challenges associated with this particular
mission. Thermal control is the maintenance of all vehicle surfaces and
components within an appropriate temperature range throughout the many
mission phases despite changing heat loads and thermal environments. For
satellites this requires that the TCS must maintain all of the equipment
within its operating and/or storage temperature range. Similar to the
system for satellites, the TCS for human-rated vehicles must also maintain
all of the equipment within their prescribed temperature ranges. In addition
to component-level temperature control, the crewed spacecraft’s TCS must
also safely and reliably maintain the internal cabin temperature to ensure
both crew survivability and comfort.
An effective TCS must provide three functions to the spacecraft: heat acquisition, heat transport, and heat rejection.
Heat acquisition is the process of acquiring excess thermal energy from various heat dissipating components including electronics, avionics, computers, and for a manned mission, metabolic heat from the crewmembers. Heat acquisition is typically accomplished using a myriad of hardware components including, but not limited to, coldplates, air/liquid heat exchangers, and liquid/liquid heat exchangers.
Heat transport is the process of moving the now acquired energy to another
location within the spacecraft. Heat transport can be accomplished using
active means such as a pumped fluid loop, but can also be performed using
more passive methods such as a simple conductive path and/or heat pipes.
Some combination of the active and passive methods is typically employed
for a manned-vehicle (and many robotic vehicles), while many small satellites
use either conductive paths or heat pipes.
The third, and final, TCS function is heat rejection, the process of rejecting
the thermal energy to the surrounding environment. Heat rejection is commonly
performed using radiators, evaporators, and/or sublimators.
Students should choose their own baseline design of a manned lunar station.
Assume a crew size of 4 to 6 persons of average height and weight. Once
this baseline has been established, the team will identify the most difficult
design challenges and potential technologies to address these challenges.