Exploring the Unknown: Selected Documents in ... - The Black Vault

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First Steps into Space: Projects Mercury and Gemini
to the astronaut were to occur) could result in an unnecessary abort. This again
results in a reduction, but not necessarily below acceptable limits, of astronaut
survivability.
3. Redundant or Backup Systems
During the presentations a great deal of stress was placed on the many
redundant features of the entire system. The basic need for alternate ways to
bring the astronaut to safety in case of system failure centers around the desire
to provide much more reliable over-all operation than can be assured from the
presently available reliability of either the Atlas or Redstone boosters. In addition,
many newly designed subsystems are involved, and there is no way to guarantee an
acceptable reliability without an inordinate amount of testing, unless the backup
or redundant system philosophy is adopted.
The following chart illustrates the multiple possibilities which are available
to bring the astronaut to safety in case of a subsystem failure. [9]
Critical Functions or Events
Accelerate to altitude
Initiation of abort
Release of escape rocket
tower, and Separation from
booster bolts.
Oxygen environment for
astronaut
Monitoring astronaut’s
condition
Attitude control of Capsule
Retro-fire
Landing
Recovery
Redundant Modes of Operation or Actuation
Normal booster operation – Abort by use of
escape rockets
Radio command from Control Center or
Blockhouse; direct actuation by astronaut; radio
command by range safety; abort sensing and
implementation system.
Electrical exploding bolts; alternate electrically
exploding bolts; direct activated exploding
Capsule pressurization; space suit with separate
oxygen system; emergency oxygen supply
Telemetry of biomedical instruments; UHF
voice link; alternate UHF voice link; HF voice
link; manual key on telemetry link.
Automatic stabilization control system with dual
sets of jets; manual control system with separate
set of jets; switch-over between the two systems.
Three rockets when two are needed; two firing
mechanisms and two power supplies.
Normal parachutes descent of capsule;
emergency chute for the capsule, and in
Redstone flight a personal chute for astronaut
egress from capsule top hatch; and emergency
side hatch
Helicopter pickup in water plus numerous
ground and sea pickup arrangements. [10]