Part Two: Wardrobe for the space shuttle era (cont.)

The extravehicular communicator attaches to the upper portion of the life support system at the back of the hard upper torso, The controls are located on the display and control module mounted on the chest at the front of the upper torso. The extravehicular communicator provides radio communication between the suited crewmember and the orbiter. In addition, electrocardiographic (EKG) information is telemetered through the extravehicular communicator to the orbiter and to flight surgeons in the Mission Control Center at Houston, Texas.

Astronaut Sherwood C. Spring wears the EMU while checking joints on a tower extending from the Space Shuttle Atlantis cargo bay during mission STS 61 -B. He is standing on the end of the arm of the remote manipulator system connected to the space shuttle.

The radios for spacewalk communications have two single UHF channel transmitters, three singlechannel receivers, and a switching mechanism. These backpack radios have a "low profile" antenna - a footlong rectangular block fitted to the top of the PLSS. The radios weigh 8.7 pounds and are 12 inches long, 4.3 inches high, and 3.5 inches wide.

Primary life support system
The PLSS consists of a backpack unit permanently mounted to the hard upper torso of the suit and a Control-and-display unit mounted on the suit chest. The backpack unit supplies oxygen for breathing, suit pressurization, and ventilation. The unit also cools and circulates water used in the liquid cooling ventilation garment, controls ventilation gas temperature, absorbs carbon dioxide, and removes odors from the suit atmosphere. The secondary oxygen pack attaches to the bottom of the PLSS and supplies oxygen if the primary oxygen fails. The control-and-display unit allows the crewmember to control and monitor the PLSS, the secondary oxygen pack, and, when attached, the manned maneuvering unit.