Gemini 8 did not land near any secondary
task groups, but it did land in the Pacific
USS Hassayampa AO-145 was assigned logistics support
for both Gemini 8 and Gemini 9, each scheduled
for Atlantic Splash Downs.
|Launch Date/Time: 1966-03-16
at 16:41:02 UTC
8 was the sixth crewed
Earth-orbiting spacecraft of the Gemini series, carrying astronauts
Armstrong and David Scott. The primary mission objectives were to
rendezvous and four docking tests with the Agena target vehicle and to
execute an ExtraVehicular Activity (EVA) experiment. Other objectives
parking the Agena in a 410 km circular orbit, performing a rerendezvous
with the Agena, conduct systems evaluation, evaluating the auxiliary
memory unit, and demonstration of controlled reentry. Ten
medical, and scientific experiments were carried on board.
Gemini 8 was launched from Complex 19 at 10:41:02 a.m. EST (16:41:02.389 UT) on 16 March 1966 and inserted into a 159.9 x 271.9 km orbit at 11:47:36. Over the next six hours the spacecraft performed 9 maneuvers to rendezvous with the Gemini Agena Target Vehicle (GATV), which had been launched earlier (at 9:00 a.m. EST). The rendezvous phase ended at 4:39 p.m. EST, with the spacecraft 45 meters apart with zero relative motion. Stationkeeping and other maneuvers were performed for about half an hour, and then Gemini 8 moved in and docked with the GATV on the 5th revolution at 5:14 p.m., the first docking ever to take place in space.
About 27 minutes after docking at 5:41 p.m. the combined vehicle began to go into a violent yaw and tumble. Armstrong disengaged the Gemini capsule from the GATV causing it to roll, pitch, and yaw even more rapidly than when it was connected to the GATV, approaching a rate of one revolution per minute. The astronauts fought to control the spacecraft for three minutes. Armstrong managed to deactivate the OAMS and in a final attempt to counteract the violent tumbling all 16 reentry control system (RCS) thrusters were utilized to damp out the roll. This manuever succeeded in stabilizing the spacecraft at 6:06:30 p.m. but ended up using 75% of the RCS fuel. It was then discovered that one of the 25-pound Orbit Atitude and Maneuver System (OAMS) roll thrusters (thruster no. 8) on Gemini 8 had been firing continuously, causing the tumbling. Apparently it had short-circuited while being used to maneuver the Gemini-GATV combination and had stuck open.
Due to the premature use of the reentry control system an immediate landing was required by Gemini safety rules, so the planned EVA and other activities were cancelled. Retrofire took place on the 7th revolution at 9:45:49 p.m. on 16 March, just over 10 hours after launch, and the spacecraft splashed down in the western Pacific Ocean about 800 km west of Okinawa at 25.22 N, 136.00 E, 2 km from the target. The time was 10:22:28 p.m. EST, but was during the day at the splashdown site. USAF frogmen parachuted from a C-54 rescue plane within minutes and affixed a flotation collar around the spacecraft. The crew was picked up by the recovery ship U.S.S. Mason 3 hours later (1:28 a.m. EST, 17 March) and the spacecraft at 1:37 a.m. Total mission elapsed time was 10:41:26.
Early termination of the mission precluded achievement of many mission objectives, but the rendezvous and docking was accomplished, as was the evaluation of the auxiliary tape memory unit and demonstration of controlled reentry. Of the six scientific experiments only the Agena micrometeorite collection was successful. The others -- (1) zodiacal light photography, (2) frog egg growth, (3) synoptic terrain photography, (4) nuclear emulsions, and (5) spectrophotography of clouds -- were incomplete. The Agena Target Vehicle remained in orbit and maneuvers were performed by ground command, including successfully placing it into circular orbit.
The adaptor module was an externally skinned, stringer framed structure, with magnesium stringers and an aluminum alloy frame. The adaptor was composed of two parts, an equipment section at the base and a retrorocket section at the top. The equipment section held fuel and propulsion systems and was isolated from the retrorocket section by a fiber-glass sandwich honeycomb blast shield. The retrorocket section held the re-entry rockets for the capsule.
The reentry module consisted mainly of the pressurized cabin which held the two Gemini astronauts. Separating the reentry module from the retrorocket section of the adaptor at its base was a curved silicone elastomer ablative heat shield. The module was composed predominantly of titanium and nickle-alloy with beryllium shingles. At the narrow top of the module was the cylindrical reentry control system section and above this the rendezvous and recovery section which holds the reentry parachutes. The cabin held two seats equipped with emergency ejection devices, instrument panels, life support equipment, and equipment stowage compartments in a total pressurized volume of about 2.25 cubic meters. Two large hatches with small windows could be opened outward, one positioned above each seat.