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Product Name: The Project Mercury Mission

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In any research and development program in which the state-of-the-art is being pressed or is about to be surmounted, there is always an undetermined number of "IF's" or unknowns. Project Mercury is just such a program. Its purpose is to investigate man's capabilities -- perhaps to confirm those capabilities -- in space. In Mercury, extreme efforts have been made to attempt to insure operating reliability mission success and pilot safety. But these are mechanical, man-made pieces of equipment and are therefore subject to malfunction. Many repetitive or backup systems have been built into the Mercury spacecraft and related equipment. From prelaunch until safe recovery, hundreds of different possible contingencies have been anticipated. For example, in the Redstone-boosted flights: If space vehicle-to-ground connections indicate an unsafe condition in the booster before lift-off and umbilical disconnect, the escape system can be fired on signal from the blockhouse through the launch vehicle or through the spacecraft umbilical line. If an unsafe condition is indicated before lift-off but after ground umbilical disconnect, the escape system can be fired by a signal from the blockhouse ground-command equipment or by the astronaut in the cockpit. If an impending catastrophic failure is indicated between lift-off and the escape tower separation about 140 seconds after launch, the automatic abort-sensing and implementation system (ASIS) can automatically initiate an escape sequence to remove the spacecraft from the booster, or the escape system can be fired by ground command from the blockhouse or by ground from the Mercury Control Center, or, by the astronaut in the cockpit. If a mission abort becomes necessary after tower separation, the spacecraft can be separated from the booster by firing the posigrade rockets on the blunt face of the spacecraft, by automatic sequencing equipment, or by the astronaut in the cockpit. Since only about ten seconds elapse between escape-tower jettison and spacecraft separation from the booster, a near-normal Redstone-boosted mission is still possible at this point. If the automatic sequencing equipment does not jettison the escape tower, the astronaut in the cockpit can trigger the system manually from the cockpit. If the spacecraft does not automatically separate from the launch vehicle at booster burnout, separation can be initiated by ground command or by the astronaut. The astronaut can initiate separation from the cockpit manually. If the automatic stabilization and control system (ASCS) fails to orient the spacecraft after separation from the booster, the astronaut has two separate manual backup control systems to achieve proper attitude control. The success of the mission and the safety of the astronaut also depend on the Life Support System, communications, and electrical power. If the automatic environmental control system, which provides the spacecraft cabin and astronaut with oxygen and temperature control fails - alternate systems can be selected manually by the astronaut. If the spacecraft pressure vessel develops a leak during flight, the astronaut's full-pressure suit automatically inflates to five pounds per square inch to provide a second closed environment. If the system which supplies oxygen to the astronaut's pressure suit fails, an emergency supply, which is in parallel with the normal supply, automatically cuts into the circuit. The astronaut can start the alternate system. If the spacecraft's main batteries fail during flight, a standby system of 15-hour duration capacity is activated automatically or manually by the astronaut. If the astronaut's primary ultra-high frequency voice link with the ground-tracking network failed, he may switch to a second UHF or high frequency channel. If the astronaut's microphone fails, a second mike in parallel with the first automatically begins to operate. If all voice link systems fail, the astronaut may resort to a code key in the cockpit and use the telemetry transmitters and frequencies to send messages back to the tracking network. If command receiver "A" fails, receiver "B" may be used to receive commands from the ground. If one telemetry transmitter fails, another with four channels will convey aeromedical information and 90 other different measurements to ground-tracking stations. If all telemetry transmission equipment fails, onboard recorders will record and preserve data for use after recovery. One of the most important phases of the flight is the landing-recovery phase. Although the retro (breaking) rockets are not needed on the Redstone-boosted flights to cause reentry, one of the objectives of these flights is to exercise the retrorockets system for "in space" qualification. This phase of the flight begins with the establishment of the proper retrorocket firing attitude and ends with the successful delivery of the spacecraft aboard the recovery ship. If the automatic attitude control system does not orient the spacecraft to the proper retrorocket firing attitude, the astronaut in the cockpit can assume attitude control through use of two alternate control systems. If the automatic timer in the cockpit does not fire the retrorockets, they can be fired by ground command from the Mercury Control Center, or, they can be fired by the astronaut in the cockpit. If the automatic system fails to initiate jettisoning of the spent retrorocket pack, the pilot can initiate the sequence from the cockpit. If the automatic system does not retract the periscope before reentry into the atmosphere, the pilot can retract it manually from the cockpit. All Systems Are Automatic In Spacecraft Since Mercury manned mission profile is to flown unmanned before man can fly the same profile, all systems must be designed, manufactured, and installed in the spacecraft to operate on a completely automated basis. Many of the primary flight actions and systems can be activated or controlled from the ground. However, it has not been possible to provide for ground control over all spacecraft systems. The introduction of the astronaut - the human observation and judgement factor - serves to enhance operational reliability to a great degree. For example, automated electronic equipment which controls the initiation of the landing and recover aids is duplicated. These systems are installed in parallel so that failure of one system should automatically cause a switchover to the alternate system. If, however, these parallel systems fail to deploy the six-foot diameter drogue parachute at about 21,000 feet, the astronaut in the cockpit can deploy the chute manually. At this point, small strips of aluminum (radar chaff) are dispersed to provide a target for radar location. If the antenna canister, to which the drogue parachute is attached, is not jettisoned to automatically deploy the main 63-foot ringsail-type landing parachute, the pilot can manually jettison the canister and deploy the main chute. If the main landing parachute does not deploy or open properly, at about 10,000 feet, a reserve landing parachute is available and can be deployed by the astronaut in the cockpit. When the main landing parachute is deployed, a SOFAR underwater bomb is deployed over the side to provide an audible sound landing point indication, and an ultra-high frequency SARAH radio beacon begins transmitting. A can of sea-marker dye is deployed with the reserve parachute and remains attached to the spacecraft by a lanyard regardless of when the reserve chute is deployed. On landing, an impact switch jettisons the landing parachute and initiates the remaining location and recovery aids. These include release of sea-marker dye with the reserve parachute if it has not previously been deployed, triggering a high-intensity flashing light, extension of a 16-foot whip antenna and the initiation of the operation of a high-frequency radio beacon. If the automatic equipment fails to release the main parachute and jettison the reserve parachute, the astronaut in the cockpit can initiate the systems manually. If the ultra-high frequency SARAH radio beacon fails, the high-frequency radio beacon automatically becomes the primary radio location aid. If both the UHF SARAH beacon and HF recovery beacons fail to operate, the astronaut's UHF and HF radio transmitters become primary location aids. If all the radio beacon location aids fail, the high-intensity flashing light and sea-marker dye become valuable aids to visual location by searching aircraft and ships. If after landing, the spacecraft should spring a leak or the life support should become fouled after landing, the astronaut can escape either through the upper neck of the spacecraft or through the side hatch. If it becomes necessary to terminate or If the flight terminates early, inadvertently, elements of the Mercury recovery forces are deployed along the intended flight path to make the recovery. If it is necessary to abort the mission, either off-the-pad or immediately after engine ignition and lift-off, emergency rescue and recovery crew and equipment have been stationed near the launch area to make the recovery. The foregoing is NOT a complete study of all redundant Mercury systems or all of the vexing "Ifs" which must be considered in the conduct of Mercury flight tests. It is intended, rather, as a primer for the layman interested in acquiring a basic understanding of contingency planning in the Mercury mission and the role of the astronaut as a "backup system" capable of greatly increasing mission reliability.

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In the next week or so, the Project Mercury's third Redstone launch will take place at Cape Canaveral. In this connection, James E. Webb, Administer or National Aeronautic and Space Administration, stated: "Our nation's space program will soon... more