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

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First Steps into Space: Projects Mercury and Gemini
spot meter is a valuable aid in photographing objects in space. Initially, station
keeping was accomplished in platform mode with minute thrust motions made
with the maneuver controller. Shortly after the start of station keeping, the sun
striking the command pilot’s window completely obscured his view of spacecraft
7. The pilot gave voice positions of the target, and finally, control was passed to the
pilot for approxi mately 1 minute until the spacecraft moved out of this sun angle.
(This effect will continue to be a problem for station keeping.) The crew did not
elect to do the in-plane fly-around at this point because they wanted to determine
the composition of the strap observed hanging from the adapter of spacecraft 7.
Shortly thereafter, the Gemini VII crew in formed the Gemini VI-A crew that they
also had a strap hanging from their adapter. This subsequently was determined to
be part of the shaped charge holders. (See section 5.1.9.) [not included]
During the final portion of the first daylight period, station keeping was
conducted in platform mode and finally in pulse mode when it was determined
to be an easy task. Spacecraft 6 closed to about 1 foot, nose to nose with spacecraft
7, and it was concluded that [7-26] docking would not present any problems. It
was also noted during this period that one spacecraft could influence the horizon
scanners of the other spacecraft.
During the first night period, station keeping was maintained at ranges
varying from 20 to 60 feet and the spacecraft were nose to nose. During the
transition from daylight to night, the blurred horizon caused the scanner to lose
track; therefore, orbit rate was selected prior to entering this period to avoid
any transients that might occur during the period of scanner loss. Station was
maintained by first using the dock ing light and platform mode, then with the
docking light and pulse mode, then without the docking light and using the
illuminated windows of spacecraft 7 as a reference. During a subsequent night
pass, an out -of-plane position was encountered where the crew could not see the
win dow of spacecraft 7. The hand-held penlights were then utilized to illuminate
spacecraft 7 at a range of approximately 30 or 40 feet. The crew determined
that they had sufficient lighting for station keeping. The most efficient way to
conduct station keeping was to maintain sta tion in horizon scan mode, letting the
spacecraft drift in yaw. The recommended position for maintaining station is in
the out-of-plane posi tion, rather than trying to maintain station above or below
the space craft. This provides a visual aid in that the horizon relative to the target
permits holding pitch and roll relatively steady in the horizon scan mode.
During the second daylight period, spacecraft 7 was scheduled to perform
an experiment and conduct a small amount of station keeping. To provide a fixed
target for the D-4/D-7 experiment, spacecraft 6 was moved to a nose-to-nose
position, 20 feet from spacecraft 7. The amount of fuel remaining in spacecraft
7 did not permit more than about 2 to 3 minutes of station keeping, and both
the command pilot and pilot ma neuvered o the nose of spacecraft 6 or this
period. Subsequent to the station keeping performed by spacecraft 7, spacecraft
6 again picked up the nose position and the command pilot initiated an in-plane
fly- around.