by NASA

“ The power divider, phase shifter, and helical antennas comprise an antenna system that satisfies the transmission and reception requirements for the re-entry C-band radar beacon during the launch and re-entry phases of the mission.
The power divider is basically a cavity type power splitter. During beacon transmission, power is delivered to the power divider where it is divided equally among the C-band helical antennas. The power divider compensates for loss of power due to the phase shifter in series with the right antenna. ”

“ The pressure sensor is a dual resistive element, diaphragm type transducer. The sensor provides signals for cryogenic fluid pressure monitoring on a spacecraft meter. The electrical heaters provide a method of accelerating pressure build-up in the reactant supply tanks. The heaters may be operated either in a manual or automatic mode. In the automatic mode a pressure switch removes power from the heater element when the tank pressure builds up to a nominal 900 psig in the oxygen tank and a nominal 250 psig in the hydrogen tank. ”

“ Suit circuit oxygen from the suit circuit demand regulator recirculates through the suit compressor, the carbon dioxide and odor absorber, the suit heat exchanger and water separator, the pressure suits, and the suit circuit solids traps. There are two compressors in the circuit. One is an alternate to be used if a compressor failure occurs. The alternate compressor is activated by positioning the SUIT FAN switch on the center panel. The cartridge of lithium hydroxide and activated charcoal remove carbon dioxide and odors of an organic nature that could have any ill effects on the pilots. ”

“ The primary oxygen supply is stored at supercritical pressure in a cryogenic spherical container in the adapter section of the spacecraft. This container is filled with liquid oxygen at atmospheric pressure. Heat is supplied by thermal leakage through the container insulation and by activation of an electric heater in order to build pressure to the critical point of 736 psia. Above this point liquid oxygen becomes a homogeneous mixture, described for simplicity as a dense supercritical fluid. This fluid is warmed, regulated and filtered before it enters the suit or cabin loop. ”

“ When a flow of electrons is allowed to do work and move to the oxygen side of the fuel cell, the reaction will proceed. By use and replacement, hydrogen ions flow through the solid electrolyte to the catalytic electrode on the oxygen side of the fuel cell. When electrons are available on this surface, oxygen disassociates and combines with the available hydrogen ions to form water. ”

“ The heat transfer characteristics and capabilities of the ground cooling heat exchanger no longer exist. The Monsanto MCS 198 coolant fluid now with no place to dissipate its internal heat, which is constantly being generated by and absorbed from the loop components, circulates about the temperature control valve of the heat exchanger. When the coolant temperature exceeds 46 +4° -2° F the temperature control valve opens to pressurize a donut shaped bellows which unseats the poppet valve exposing the water in the heat exchanger core to reduced pressure as altitude increases during launch. ”

“ REAL-TIME TELEMETRY TRANSMITTER Orbital operation of the real-time telemetry transmitter is similar to that of the delayed-time telemetry transmitter in that the real-time telemetry transmitter is operated only during the period that the spacecraft is within range of a ground station. The real-time telemetry transmitter is turned on by a DCS command from the ground station or by placing the T/M CONTROL switch to the R/T & ACQ or RT-D/T position. Real-time transmission is by the uhf stub or the retrograde uhf whip antenna, depending upon the position of the ANT SEL switch. ”

“ Sensors detect the ejection of the seats and notify the blockhouse that the pilots are out of the spacecraft. One-quarter second after the seats are ejected, a sustainer rocket under each seat is fired, which extend the distance between the pilots add the launch vehicle. Then a pyrotechnic ignites and separates the ejection seat from the pilots. Two seconds after sustainer ignition, the main parachutes have opened and the pilots are lowered safely to the ground. ”

“ No primary ac electrical power system Is provided for the spacecraft. Devices requiring ac power obtain this power from self-contained inverters within the individual systems.
The Electrical Power System includes switches, circuit breakers, relay panels, ammeters, a voltmeter and telelights which provide control, distribution and monitoring for the system. Also included as an Electrical Power System subsystem is the Reactant Supply System (RSS) which provides storage and control of the reactants (hydrogen and oxygen) used for fuel cell battery operation (not applicable to spacecraft 6) . ”

“ The R and R and RCS section surfaces are made up of unbeaded shingles of beryllium. The shingles protect the re-entry module structure from excessive heat and provide additional rigidity for the cabin. The shingles are black on the outer surface to control thermal radiation. The inner surface of the beryllium shingles are coated with gold to provide a low emissivity surface.
ADAPTER The adapter functions to mate the spacecraft to the launch vehicle, to provide for mounting equipment and retrograde rockets , and to serve as a radiator for the spacecraft coolant system. ”

“ The fluid flows from the supply tanks to the heat exchangers. The fluid temperature, when entering the heat exchangers is approximately -279°F for the oxygen and approximately -423°F for the hydrogen. The heat exchangers absorb heat from the recirculating coolant fluid of the spacecraft cooling system. This heat, applied to the high density fluid, raises the temperature of the reactants to approximately 50°F to 140°F.
The reactants, now in gaseous form, flow through the heat exchangers, past the high pressure relief valves and AGE temperature sensors, to the supply solenoid shutoff valves. ”

“ Deployment of the survival kit is automatic if the pilot ejects and is also available to the pilot if he lands with the spacecraft.
Deployment of the survival kit during the ejection cycle takes place as the backboard and seat falls away from the parachuting pilot. As the backboard falls, the survival kit lanyard, connected to the pilots harness, pulls a pin on the life raft container. When the pin is removed, the daisy chain loops are disengaged and the life raft and rucksack are extracted from the container. ”

“ If the drogue parachute fails or has not been deployed before the spacecraft descents to 10,600 feet, the emergency main parachute switch is used to deploy the main parachute.
If one of the two first stage engines should fall and the launch vehicle is above 40,000 feet, the pilots may elect to remain with the spacecraft until the operating engine has boosted them to 75,000 feet. At this altitude, abort mode I-II becomes inapplicable. ”

“ Spacecraft control bus voltage is supplied through the WHIP ANTENNAS - HF circuit breaker to the HF ART switch, which has momentary type contacts. During orbit, the LANDING switch is in the SAFE position and adapter hf whip antenna can be extended or retracted by holding the HF ANT switch in the EXT or RET position respectively. During re-entry, the LANDING switch is placed in the ARM position. After landing, the recovery hf whip antenna can be extended or retracted by holding the HF ANT switch in the EXT or RET position respectively. ”

“ The line filter prevents noise on the input power bus from affecting transmitter operation and prevents transients generated within the transmitter from feeding back to the input power bus. The multipin power connector J2 is an integral part of the line filter.
The dc-dc converter is a completely encapsulated unit employing transistors, diodes and a transformer to provide regulated outputs of 30 vdc and 70 vdc from an unregulated input voltage of 18 to 30.5 vdc. The converter is a constant power input type, thus minimizing the heat dissipation caused by high voltage inputs. ”

“ PCM pulse trains from the PCM programmer and voice tape recorder. The real-time transmitter provides the ground monitoring stations with current real-time data at a rate of 51.2 kilobits per second. The delayed time transmitter provides the ground monitoring station with data stored on the tape recorder while the spacecraft was between ground stations. The delayed-time data is transmitted at a rate of 112.6 kilobits per second. The stand-by transmitter is used as backup for the real-time or delayed-time transmitters in event of a failure in either transmitter. ”

“ When thrust decay is complete, the command pilot, depresses and releases the SEP SPCFT switch-indicator on the mean instrument panel. When the contacts of the SEP SPCFT switch-indicator closes, squib bus number 1 power is applied through the closed BOOST-INSERT CONT 1 circuit breaker to relays K3-22, K3-24, and K3-42. K3-22 is the spacecraft shaped charge ignition relay. K3-24 is the launch vehicle/spacecraft wire guillotine relay. K3-42 is the uhf whip antenna extend relay. Redundant contacts of the SEP SPCFT switch-indicator energize redundant relays with power from squib bus number 2. ”

“ SEAT EJECTION SYSTEM The seat ejection system provides the crew with a means of escaping from the vicinity of the spacecraft in the event of an abort or in an emergency condition during launch or re-entry. Crew member seats are ejected by means of rocket/catapults. Hot gas from each of the hatch actuators is routed to the appropriate seat catapult where dual firing pins strike dual percussion primers, thereby igniting the seat rocket/catapult main charge and ejecting the seats from the spacecraft. ”

“ REACTANT SUPPLY SYSTEM The RSS is essentially a subsystem for the fuel cell battery sections. The system provides storage for the cryogenic hydrogen and oxygen, converts the reactants to gaseous form and controls the flow of the gases to the fuel cell battery sections. The RSS components are installed in the RSS/fuel cell module. On spacecraft 10, 11 and 12, the RSS O2 requirements are supplied from a central cryogenic O2 tank located in the RSS/fuel cell module. ”

“ Operation of the egress oxygen system is initiated by three of the four lanyards which are pulled when the seat leaves the spacecraft. One lanyard pulls a pin in the composite disconnect allowing it to separate and close the normal suit circuit. Two of the remaining lanyards open the container shutoff valve and circuit relief valve activating the egress oxygen system.
Each of the egress oxygen containers is pressurized to 1800 psig with gaseous oxygen. The oxygen flows from the containers through a pressure regulator, where the pressure is reduced to 40 psia. ”