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

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First Steps into Space: Projects Mercury and Gemini
2. The equipment installation at all of the major tracking stations is
nearing completion. Stations ready to go include the control center at Canaveral,
the computers at Goddard, the communications center at Goddard, the subsidiary
center at Bermuda, the Atlantic ship, and Canary Islands. The mainland-Bermuda
complex was tested on MR-2 (MR – Mercury Redstone) and MA-2 and the net as far as
the Canary Islands will be tested on MA-3. Installation is continuing at other stations
and checkouts are being made with the aid of aircraft-borne instrumentation, but the
world-wide net will not be ready for full operation until about 5/1/61.
3. Pilots have been selected. They have been subjected to a training
program including performance at high g and under weightless conditions.
They have practiced the manual controls in simulators and have flown simulated
missions with surprise emergencies occurring. They have practiced leaving the
capsule in the water and under water. [4]
4. Recovery operations have been rehearsed and organization of the
world-wide recovery and rescue system is proceeding.
The program is approaching the state where manned suborbital flight is
contemplated in the near future. The question of our readiness will be discussed
at length later in the report since there are still serious problems. Manned orbital
flight is probably about a year away but a number of problems must still be solved
before such a launch.
IV.
Assessment of Risk and Probability of Success
1. The Reliability Problem
In the assessment of probable system performance, there are two distinct
analyses to be made:
(a) Probability of mission success;
(b) Probability of astronaut survival.
Both of these depend on subsystem and component reliabilities, but in
very different ways; e.g., a booster failure means mission failure but by no means
implies an astronaut fatality or injury.
Thus an estimate of either of these probabilities must begin with the
failure probabilities of the individual subsystems. Two remarks of somewhat
opposing tendency are important here. The first is that subsystem failure
probabilities are not really independent numbers. There are always interactions,
or correlations, among subsystems and components such that the failure of
subsystem “A” will make the failure of subsystem “B” more probable than before.
In large missile systems, it is not feasible to assess these interactions numerically
with any degree of confidence without a large number of launchings. However,
it is well to remember they are there. The second remark is that except for the
booster the system, its several subsystems and even the components themselves
are provided with a generous degree of redundancy, both at the hardware level