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

350
First Steps into Space: Projects Mercury and Gemini
The relative motion of spacecraft 6 from the separation maneuver was stopped at
a range of about 30 miles.
The spacecraft and its systems performed very satisfactorily throughout
the mission, except for the delayed-time telemetry tape recorder which failed
at 20 hours 55 minutes ground elapsed time be cause of a bearing seizure. This
recorder malfunction resulted in the loss of all delayed-time telemetry data for
the remainder of the mission.
The flight progressed nominally to its full duration. All check lists and
stowage were completed in preparation for retrofire and re entry and the reentry
control system was activated. Retrofire occurred exactly on time at 25:15:58 ground
elapsed time for a landing in the West Atlantic landing area (primary). The reentry
and landing were nominal, and the landing point achieved was less than 7 nautical
miles from the planned landing point. The crew remained in the spacecraft until
the spacecraft had been secured on the deck of the recovery ship.
[pp. 2-1 through 7-17 not included]
[7-18]
7.1.2.3 Rendezvous Phase. -
7.1.2.3.1 Radar acquisition of spacecraft 7: At approximately 3 hours
g.e.t., the ground update for acquisition of spacecraft 7 was received as an attitude
of or yaw and 5.50 pitch up. The ground con trollers also indicated that the initial
computer readout of range (248 nautical miles) would occur at 3 hours 15 minutes
g.e.t. The [7-19] radar was turned on in the standby position at approximately
3 hours 5 minutes g.e.t. The analog meter indication cycled exactly as pre dicted,
and the range and range rate indications oscillated until the set warmed up. The
radar was then placed on “ON”.
The first radar-range readout on the MDRU was 248.66 nautical miles,
which is the maximum range readable. At this time, the radar lock-on light was
flickering. The radar lock-on became steady at 246.22 nautical miles, At that time,
a radar test was performed with the rendezvous mode of the computer to verify
the interface and sequenc ing of the computer and the radar. This radar-computer
test was not conclusive in that the specified 130° angle of orbit travel to rendez vous
(wt) was not inserted and the last wt that was loaded was 180°, which had been
used for a prelaunch test. Subsequent to the N SR
ma neuver and the final switching
to the rendezvous mode, the correct value of wt (130°) was loaded. The computer
cycled properly, holding the range in the register for 100 seconds, and the IVI’s
corresponded to the computer readout of total-velocity-change for rendezvous.
The initial-velocity-change for target intercept was also noted, and the values were
found to be decreasing as range decreased. The event timer was synchronized
with the initiation of the N SR
maneuver. Four min utes after initiation of the N SR
maneuver, the computer was switched to the rendezvous mode and continuously
monitored by the pilot. A time synchronization revealed that the event timer was
approximately 7 sec onds ahead of the computer time sequence (for 100-second
intervals). The event timer was resynchronized with the computer-time and counted