The
rendezvous techniques used on the
previous missions required multiple revolutions of the Earth before
rendezvous was achieved.
The plan for Gemini XI was to rendezvous within a single revolution.
This was important because that is what was planned when a lunar
landing would be attempted in the Apollo program.
Another goal for Gemini XI was to fly higher than any manned spacecraft
had ever flown in history. This was to be accomplished through
the use of the main engine on the Agena docking target vehicle.
The commander selected for Gemini XI was veteran astronaut Charles
(Pete) Conrad, Jr. His pilot would be Richard F. Gordon, Jr.
Gemini Titan XI was launched on September 12, 1966. The Titan performed
nominally and a very accurate orbital insertion was achieved.
Since the goal was to achieve rendezvous with the target Agena within
one orbit, the crew was very busy during their first orbit. They
made onboard calculations to determine what thruster firings were
required for achieving rendezvous. 85 minutes after launch, Conrad and
Gordon achieved a single orbit rendezvous over the coast of California.
Docking with the Agena went very well. In fact the mission up to
this point had gone so smoothly that Conrad and Gordon had a chance to
practice undocking and docking with the Agena. Each man undocked
and docked with the Agena twice, once in sunlight and once in darkness.
The crew
rested for the night. The next morning, the first task
was an EVA by astronaut Gordon. Preparation for the EVA did not go very
smoothly. The crew was ahead of the time line and Gordon ended up
getting overheated in his EVA gear while waiting to leave the cabin.
One of Gordon's objectives for the EVA was to attach a tether between
the Gemini spacecraft and the Agena. This tether would later be
used for artificial gravity experiments. Gordon encountered some
difficulty in positioning himself between the junction of the Gemini
and Agena. To free his hands for the tethering operation, Gordon
put a leg on each side of the Gemini's nose. At this point
astronaut Gordon resembled a space age cowboy trying to subdue an
unruly steed.
As the EVA progressed, Gordon got hotter and hotter from the
exertion. Sweat was stinging his eyes but he did manage to secure
the tether. Gordon then moved to the back of the Gemini
spacecraft and was nearly blind from the sweat getting in his eyes.
Commander Conrad called Gordon back in and the EVA was terminated early.
Once again the environment of space proved much different than the
training exercises on the Earth. Although it was a simple task
during training, it proved to be a monumental challenge during the
EVA. Even the micro gravity training on NASA's zero-g airplane
was insufficient when it came to the actual mission. The
difficulties encountered on the Gemini EVAs up to this point did not
instill much confidence in the Apollo mission planners.
The next day Conrad and Gordon prepared the Gemini and Agena vehicles
for an extended duration burn by the Agena's main rocket engine.
This burn was to propel them into an orbit higher than any orbit ever
achieved by a manned spacecraft.
The rocket engine burned for 26 seconds. It must have been quite
a ride because Conrad exclaimed "Whoop-de-doo!
... The biggest thrill
of my life." The spacecraft was now in an orbit whose
highest
point was 850 nautical miles above the Earth. From this vantage
point the view of the Earth was much different. The curvature of
the Earth was much more apparent than it was before.
After two orbits, the Agena main engine was fired again. This
time it was to bring the Gemini and Agena down into a lower
orbit. There was some concern about remaining in the high orbit
too long as the Van Allen radiation belts could subject the crew to
dangerous radiation.
The next task for
the crew was a standup EVA by Gordon. This time
he would not exit the spacecraft but merely stand up in his seat to
take photographs of star fields. In contrast with his first EVA,
Gordon experienced no difficulty with the stand up EVA. In fact
it was so leisurely that at one point Gordon catnapped while floating
in the open hatch of the Gemini spacecraft.
The crew undocked from the Agena but remained connected to it through
the 30 meter tether that Gordon had attached during his first
EVA. The goal was to back the Gemini away from the Agena so that
the tether would become taught. After the slack was out of the
tether, a rotation
would be imparted in the tethered vehicles to produce centrifugal force
to act as artificial gravity.
Making the tether taught in the micro gravity environment proved to be
a difficult task. It did not want to stay tight and oscillations
were induced in two vehicles. The experiment however was
successful and after some time in this configuration the Gemini
spacecraft jettisoned the tether.
The re-entry of Gemini XI would also be a first in space. It was
the first time that the spacecraft would control itself by autopilot
without human intervention. On September 15 and after 44 orbits Gemini
splashed down 2.8 miles away from the recovery aircraft carrier, the
U.S.S. Guam. The automatic re-entry was successful and very
accurate.
Gemini XI's flight duration was 2 days, 23 hours, 17 minutes, and 8
seconds.
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