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

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First Steps into Space: Projects Mercury and Gemini
2.2.1 Launch Window The second vehicle involved in the
rendezvous must be launched very close to a prescribed
time if the operation is to be economical in terms of
waiting time and propulsion requirements. This requires
a major simplification of the countdown procedure and
high reliability of equipment.
2.2.2 Navigation Means must be developed for maneuvers
in space, using information supplied by the navigation
system.
2.2.3 Guidance and Control Guidance and control techniques
must be developed for maneuvers in space, using
information supplied by the navigation system.
2.2.4 Docking Rendezvous is not effective until the docking
maneuver is accomplished. The space environment
makes this operation quite a bit different from the
same type of operation within the earth’s atmosphere
and hence considerable work in developing suitable
techniques is to be expected.
2.3 Controlled Land Landings Experience has shown that the
magnitude of the effort required to deploy adequate naval forces
for the recovery of the Mercury spacecraft at sea is such that any
means for avoiding, or at least minimizing, this effort would be
highly desirable. The sea has proved to be a more inhospitable
environment for recovery than was originally envisioned. If space
flights are to be accomplished on anything like a routine basis,
spacecraft must be designed to alight on land at specified locations.
This requires that the landing dispersion be reduced to a very low
figure, and a satisfactory method of touchdown developed.
2.3.1 Dispersion Control To effect control of the landing
area, it is fundamental that an impact prediction be
made available to the pilot and a means provided for
controlling the spacecraft so the desired impact point
can be reached.
2.3.2 Landing Impact The attenuation of the impact loads
which might result from a land landing of the Mercury
spacecraft has presented a very considerable problem.
Although it is estimated that in many cases the landing
accelerations would be within tolerable limits, the random
nature of the landing process has made it impossible
to consider a sufficient variety of conditions that could
be encountered so as to have adequate assurance [7]
of success. In order to guarantee safety in landing, the
impact must be made at a relatively low velocity and in a
selected area.