NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Gemini 10

NSSDCA/COSPAR ID: 1966-066A

Description

Gemini 10 was the eighth crewed Earth-orbiting spacecraft of the Gemini series, carrying astronauts John Young and Michael Collins. Its primary purpose was to conduct rendezvous and docking tests with the Agena target vehicle. The mission plan included a rendezvous with the Gemini 8 Agena target, two extravehicular activity (EVA) excursions, and the performance of 15 scientific, technological, and medical experiments. The scientific experiments were related to (1) zodiacal light, synoptic terrain, and synoptic weather photography, (2) micrometeorite collections, (3) UV astronomical camera, (4) ion wake measurements, and (5) meteoroid erosion.

Mission Profile

Gemini 10 was launched on 18 July from Complex 19 at 5:20:26 p.m. EST (22:20:26.648 UT) and inserted into a 159.9 x 268.9 km orbit. At orbit insertion Gemini 10 was about 1600 km behind the Gemini Agena Target Vehicle 10 (GATV-10) which had been launched into a near circular orbit about 100 minutes earlier. Rendezvous with GATV-10 was achieved on the 4th revolution at 10:43 p.m. and at 11:13:03 p.m. docking was achieved. A large out-of-plane error in the initial orbit required the Gemini to use 60% of its fuel for the rendezvous, over twice the planned amount. As a result most of the mission plan was revised. To conserve fuel, Gemini 10 remained docked to GATV-10 for the next 39 hours and used the GATV propulsion system for maneuvers. The planned docking practice runs were cancelled.

A 14-second burn of the GATV-10 primary propulsion system was used to raise the dual spacecraft apogee to 764 km. While the spacecraft were docked, a bending mode test was conducted to study spacecraft dynamics and other experiments were performed. Another burn of GATV-10 at 3:58 p.m. on 19 July brought the spacecraft into the same orbit as the GATV-8, which had been launched on 16 March for the Gemini 8 mission. At 4:44 p.m. the Gemini cabin pressure was reduced to zero and the hatch was opened. Collins stood up in his seat 3 minutes later and began photographing stellar UV radiation. Partway into the standup EVA Young and Collins began to experience severe eye irritation from an unidentified source and Young ordered termination of the EVA. Collins sat down and the hatch was closed at 5:33 p.m., and a high oxygen flow rate was used to purge the environmental control system.

Gemini 10 separated from GATV-10 at 2:00 p.m. EST on 20 July. A series of manuevers using its own thrusters brought Gemini 10 within about 15 meters of GATV-8. At 6:01 p.m. (48:41 ground elapsed time) the cabin was evacuated and the hatch opened for Collins to begin his second EVA. Collins left the spacecraft 6 minutes later attached to an umbilical cord and travelled to the GATV-8. Despite difficulties due to lack of handholds on the target vehicle Collins removed the fairing and retrieved the micrometeoroid detection equipment. During the EVA he lost his camera. He also retrieved the micrometeorite experiment mounted on the Gemini 10 spacecraft, but this apparently floated out of the hatch and was lost when Collins reentered the capsule. The EVA was limited to 25 minutes of outside activity due to lack of fuel. Collins reentered the capsule at 6:32 p.m. and the hatch was closed at 6:40. The hatch was reopened again at 7:53 p.m. to jettison 12 items before reentry. After about three hours of stationkeeping Gemini 10 moved away from GATV-8. At 8:59 p.m. the crew performed an anomaly adjust maneuver to minimize reentry dispersions resulting from the retrofire maneuver.

Retrorocket ignition took place during the 43rd revolution on 21 July at 3:30:50 p.m. EST and splashdown occurred at 4:07:05 p.m. in the western Atlantic at 26.74 N, 71.95 W, 875 km east of Cape Kennedy and 6.3 km from the target point. The crew was picked up by helicopter and taken to the recovery ship U.S.S. Guadalcanal at 4:34 p.m. and the spacecraft was aboard at 5:01 p.m. Total mission elapsed time was 70:46:39. Of the primary objectives, only the docking practice was not accomplished due to lack of fuel, although the fuel budget also resulted in small revisions in some of the other objectives. The first rendezvous and docking maneuvers were successfully accomplished. All experiments obtained data except for the Gemini 10 micrometeorite collector, which was lost by floating out of the spacecraft. The landmark contrast measurement experiment was deleted due to lack of fuel. Gemini 10 demonstrated the ability of an astronaut to travel to another spacecraft and back and the use of powered, fueled satellite to provide propulsion for a docked spacecraft.

Spacecraft and Subsystems

The Gemini spacecraft was a cone-shaped capsule consisting of two components, a reentry module and an adaptor module. The adaptor module made up the base of the spacecraft. It was a truncated cone 228.6 cm high, 304.8 cm in diameter at the base and 228.6 cm at the upper end where it attached to the base of the reentry module. The re-entry module consisted of a truncated cone which decreased in diameter from 228.6 cm at the base to 98.2 cm, topped by a short cylinder of the same diameter and then another truncated cone decreasing to a diameter of 74.6 cm at the flat top. The reentry module was 345.0 cm high, giving a total height of 573.6 cm for the Gemini spacecraft.

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.

Control, Propulsion, and Power

Attitude control was effected by two translation-maneuver hand controllers, an attitude controller, redundant horizon sensor sytems, and reentry control electronics, with guidance provided via an inertial measuring unit and radar system. The orbital attitude and maneuver system used a hypergolic propellant combination of monomethylhydrazine and nitrogen tetroxide supplied to the engines by a helium system pressurized at 2800 psi. Two 95 lb translation thrusters and eight 23 lb attitude thrusters were mounted along the bottom rim of the adaptor, and two 79 lb and 4 95 lb thrusters were mounted at the front of the adaptor. Power was supplied by a fuel cell power system to a 22- to 30-volt DC two-wire system. During reentry and post-landing power was supplied by four 45 amp-hr silver-zinc batteries.

Communications

Voice communications were performed at 296.9 MHz with an output power of 3 W. A backup transmitter-receiver at 15.016 MHz with an output power of 5 W was also available. Two antenna systems consisting of quarter-wave monopoles were used. Telemetry was transmitted via three systems, one for real time telemetry, one for recorder playback, and a spare. Each system was frequency-modulated with a minimum power of 2 W. Spacecraft tracking consisted of two C-band radar transponders and an acquisition-aid beacon. One transponder is mounted in the adaptor with a peak power output of 600 W to a slot antenna on the bottom of the adaptor. The other is in the reentry section, delivering 1000 W to three helical antennas mounted at 120 degree intervals just forward of the hatches. The acquisition-aid beacon was mounted on the adaptor and had a power of 250 mW.

Reentry

At the time of reentry, the spacecraft would be maneuvered to the appropriate orientation and equipment adaptor section would be detached and jettisoned, exposing the retrorocket module. The retrorockets consisted of four spherical-case polysulfide ammonium perchlorate solid-propellant motors mounted near the center of the reentry adaptor module, each with 11,070 N thrust. They would fire to initiate the spacecraft reentry into the atmosphere, with attitude being maintained by a reentry control system of 16 engines, each with 5.2 N thrust. The retrorocket module would then be jettisonned, exposing the heat shield at the base of the reentry module. Along with the ablative heat shield, thermal protection during reentry was provided by thin Rene 41 radiative shingles at the base of the module and beryllium shingles at the top. Beneath the shingles was a layer of MIN-K insulation and thermoflex blankets. At an altitude of roughly 15,000 meters the astronauts would deploy a 2.4 meter drogue chute from the rendezvous and recovery section. At 3230 meters altitude the crew releases the drogue which extracts the 5.5 meter pilot parachute. The rendezvous and recovery section is released 2.5 seconds later, deploying the 25.6 meter main ring-sail parachute which is stored in the bottom of the section. The spacecraft is then rotated from a nose-up to a 35 degree angle for water landing. At this point a recovery beacon is activated, transmitting via an HF whip antenna mounted near the front of the reentry module.

Gemini Program

The Gemini program was designed as a bridge between the Mercury and Apollo programs, primarily to test equipment and mission procedures in Earth orbit and to train astronauts and ground crews for future Apollo missions. The general objectives of the program included: long duration flights in excess of of the requirements of a lunar landing mission; rendezvous and docking of two vehicles in Earth orbit; the development of operational proficiency of both flight and ground crews; the conduct of experiments in space; extravehicular operations; active control of reentry flight path to achieve a precise landing point; and onboard orbital navigation. Each Gemini mission carried two astronauts into Earth orbit for periods ranging from 5 hours to 14 days. The program consisted of 10 crewed launches, 2 uncrewed launches, and 7 target vehicles, at a total cost of approximately 1,280 million dollars.

Alternate Names

  • 02349

Facts in Brief

Launch Date: 1966-07-18
Launch Vehicle: Titan II
Launch Site: Cape Canaveral, United States
Mass: 3762.6 kg

Funding Agency

  • NASA-Office of Manned Space Flight (United States)

Disciplines

  • Astronomy
  • Earth Science
  • Human Crew
  • Planetary Science
  • Space Physics

Additional Information

Questions or comments about this spacecraft can be directed to: Dr. David R. Williams.

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. William C. SchneiderProject ManagerNASA Headquarters 
Dr. Charles W. MathewsProject ManagerNASA Headquarters 
Dr. George E. MuellerProgram ManagerNASA Headquartersinfo@kistleraero.com

Selected References

Gemini summary conference, NASA, SP-138, Wash, DC, Feb. 1967.

Zeitler, E. O., and T. G. Rogers, Gemini program - physical sciences experiments summary, NASA-MSC, TM-X-58075, Houston, TX, Sept. 1971.

Grimwood, J. M., et al., Project Gemini technology and operations - A chronology, NASA, NASA SP-4002, Wash., DC, 1969.

[USA.gov] NASA Logo - nasa.gov