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  The planned EVA by David Scott on Gemini 8

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Author Topic:   The planned EVA by David Scott on Gemini 8
LM-12
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posted 07-20-2013 01:12 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Here is a description from the press kit of how the Gemini 8 EVA by David Scott would have unfolded had the in-flight emergency not occurred.

The Gemini spacecraft and the Agena Target Vehicle would have been docked when the EVA began. It is interesting that Scott would have been in the rear of the adapter section wearing the ESP (Extravehicular Support Package) when Gemini and Agena undocked.

At the 18th hour after liftoff, the crew will prepare for the pilot's extravehicular activity. The ELSS chest pack (see Crew Provisions Section for details of EVA equipment) will be unstowed, along with the 25-foot umbilical tether and "Y" connectors. The command pilot will lower cabin pressure to 3.5 psi for systems check and then completely depressurize the cabin. The pilot is scheduled to open the hatch at 20:30 GET, and at sunrise at the end of the 13th revolution, the pilot will emerge from the spacecraft at 20:41 GET.

On the first daylight pass over the United States, the pilot will perform the following tasks. While standing on the seat, he will mount the extravehicular camera facing forward, then retrieve the S-9 experiment on the retro adapter directly behind his seat. Then he will move to the target docking adapter and open the S-10 micrometeroid experiment mounted there. He will return to the spacecraft, change film in the camera and face it aft, then clean and sample the spacecraft windows. The pilot then moves to the rear of the adapter section to check the ESP equipment. He returns to the retro adapter and performs the D-16 power tool experiment. Prior to sunset, he moves to the rear of the adapter section to don the ESP.

During the night pass (45 minutes) the pilot will stay in the adapter section, donning the extravehicular equipment. At second sunrise, the command pilot will undock the Gemini from the Agena and translate 60 feet out-of-plane to fly formation with the Agena. He will then separate the back pack from the adapter section and the pilot will move to the nose of the Gemini.

The EVA pilot will then evaluate the 75-foot tether and the HHMU. He will move out from the spacecraft to the 15-foot point on the tether. The pilot will then translate below the Agena by ten feet, and the command pilot will maneuver the spacecraft to null any angular motion between the spacecraft and the EVA crewman. The EVA pilot will move successively to the 45-foot connect point and the 75-foot connect point on the tether. When he has finished HHMU maneuvers at 75 feet, the command pilot will maneuver the spacecraft to the pilot.

The command pilot will follow the pilot as he translates to the Agena. The pilot will then follow the spacecraft at 50 feet as the command pilot translates from the Agena. Ingress will be in the 15th revolution while flying formation with the Agena at 250 feet. Total time of EVA will be two hours, 10 minutes.

After EVA is completed, the command pilot will re-dock with the Agena.

Tom
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posted 07-20-2013 08:29 AM     Click Here to See the Profile for Tom   Click Here to Email Tom     Edit/Delete Message   Reply w/Quote
Thanks for posting... quite a bit more complicated than previous EVA on Gemini 4!

garymilgrom
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posted 07-20-2013 09:16 AM     Click Here to See the Profile for garymilgrom   Click Here to Email garymilgrom     Edit/Delete Message   Reply w/Quote
Very surprised they would have someone outside during an undocking. That seems overly risky for the second EVA but it also shows NASA's can-do attitude from this time.

LM-12
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posted 07-20-2013 10:04 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Dave Scott would have jettisoned the ESP and the 75-foot tether aft of the Gemini spacecraft just before EVA ingress.

Fra Mauro
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posted 07-20-2013 01:04 PM     Click Here to See the Profile for Fra Mauro   Click Here to Email Fra Mauro     Edit/Delete Message   Reply w/Quote
It also shows to me how unknown the complexities of an EVA were understood back in 1966. Imagine the disaster if the thruster problem had occurred during the EVA.

LM-12
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posted 07-20-2013 01:40 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
This photo of the EVA equipment for Gemini 8 shows the chest-mounted ELSS and the ESP back pack. He is holding the HHMU in his right hand. The ESP was similar in shape to the AMU on Gemini 9A.

LM-12
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posted 07-20-2013 10:01 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by garymilgrom:
Very surprised they would have someone outside during an undocking.

That was the plan for Gemini 9A also. Tom Stafford was to undock the Gemini 9A spacecraft from the ATDA while Gene Cernan was in the adapter section strapped to the AMU.

mach3valkyrie
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posted 07-20-2013 10:36 PM     Click Here to See the Profile for mach3valkyrie   Click Here to Email mach3valkyrie     Edit/Delete Message   Reply w/Quote
Imagine the photographs of Scott's EVA had the mission proceeded as planned!

LM-12
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posted 07-20-2013 10:56 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Gemini 9A had a docking bar mirror. Gemini 8 would have had one also. One of the early EVA tasks for Dave Scott was to "attach mirror to docking bar" shortly after exiting the hatch. The mirror would have been in his suit pocket.

Neil Armstrong would have had a great view of the EVA just as Tom Stafford did.

LM-12
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posted 07-23-2013 02:59 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
... and at sunrise at the end of the 13th revolution, the pilot will emerge from the spacecraft ...
Here is how the Gemini press kit explains orbits and revolutions:
The spacecraft's course is measured in revolutions around the Earth. A revolution is completed each time the spacecraft passes over 80 degrees west longitude, or at Gemini altitudes about once every 96 minutes.

Orbits are space referenced and in Gemini take about 90 minutes.

The longer time for revolutions is caused by the Earth's rotation. As the spacecraft circles the Earth, the Earth moves about 22.5 degrees in the same direction. Although the spacecraft completes an orbit in about 90 minutes, it takes another six minutes for the spacecraft to reach 80 degrees west longitude and complete a revolution.

Gemini completes 16 orbits per day, but in 24 hours crosses the 80th meridian of longitude 15 times -- hence 15 revolutions per day.

onesmallstep
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posted 07-24-2013 10:45 AM     Click Here to See the Profile for onesmallstep   Click Here to Email onesmallstep     Edit/Delete Message   Reply w/Quote
For those that may not have seen it, Space History Photo of the Week #373 (12/24/11) has a photo of Cernan taken by Stafford using the docking bar mirror used on GT-9A.

LM-12
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posted 07-24-2013 12:12 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
The flight plan indicates that Gemini 8 and Agena would have been docked when the EVA began, with the Agena at 0°, 90°, 0° and the spacecraft at 0°, -90°, 0°.

I'm guessing that is 90° yaw, and perpendicular to the direction of flight.

LM-12
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posted 07-24-2013 04:03 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Here are two colour photos of the Gemini 8 EVA equipment: 1 | 2

LM-12
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posted 07-26-2013 09:32 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
This paragraph is from the program mission report for Gemini 8:

A hatch holding device was added to both hatches. This was a tooth and ratchet system with the tooth mounted on the center torque box of the cabin and the ratchet attached to the hatch. To provide EVA capability through either hatch, a hatch closing device and attaching eyebolts were added to the left hatch and were the same as the existing installation on the right hatch. Hatch rigging procedures were changed to insure compatability with the hatch holding device.

LM-12
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posted 07-27-2013 07:20 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Handrails and velcro patches were added to the exterior of the Gemini spacecraft to assist Dave Scott during his planned EVA.

LM-12
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posted 08-06-2013 09:54 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Here is the EVA section of the Gemini 8 flight plan: page 60 | 61 | 62 | 63 | 64

Delta7
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posted 08-06-2013 10:32 PM     Click Here to See the Profile for Delta7   Click Here to Email Delta7     Edit/Delete Message   Reply w/Quote
Interesting to remember this EVA was the main reason that Elliot See was bumped from the flight by Deke Slayton and promoted to Command Pilot of Gemini 9.

LM-12
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posted 08-07-2013 01:41 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
This EVA illustration shows how Dave Scott would have made his way aft to the adapter section to don the ESP. Between steps 5 and 6, Neil Armstrong would have undocked Gemini and Agena, and deployed the back pack from the adapter.

LM-12
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posted 08-24-2013 12:38 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Here is a summary table of all the Gemini EVA activity from NASA SP-149.
Extravehicular activity (EVA) was accomplished on 5 of the 10 manned Gemini missions. A total of 6 hours and 1 minute was accumulated in five extravehicular excursions on an umbilical. An additional 6 hours and 24 minutes of hatch-open time was accumulated in six periods of standup EVA including two periods for jettisoning equipment. The total extravehicular time for the Gemini Program was 12 hours and 25 minutes.

LM-12
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posted 08-24-2013 09:30 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
The EVA crewmembers were White, Scott, Cernan, Collins, Gordon and Aldrin.

LM-12
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posted 08-28-2013 10:20 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Here are some 1966 LIFE magazine photos of the USS Leonard F. Mason arriving in Okinawa on March 18 after the Gemini 8 recovery.

Wally Schirra was in Hawaii and flew to Okinawa to meet the crew and fly back with them to Cape Canaveral. The spacecraft was safed at Naha Air Base in Okinawa and transported back to the McDonnell facility in St. Louis, Missouri.

LM-12
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posted 09-20-2013 10:50 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
How long was Gemini 8 docked to the Agena before the emergency occurred?

mach3valkyrie
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posted 09-20-2013 02:19 PM     Click Here to See the Profile for mach3valkyrie   Click Here to Email mach3valkyrie     Edit/Delete Message   Reply w/Quote
Off the top of my head, 30 minutes, give or take. I'm sure there is a precise number, but this is the one I've got at the moment.

onesmallstep
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posted 09-20-2013 04:02 PM     Click Here to See the Profile for onesmallstep   Click Here to Email onesmallstep     Edit/Delete Message   Reply w/Quote
On the scribd.com website, a copy of the air-to-ground voice transcript shows that docking to the Agena was announced at 6:33:52 MET by Armstrong, and the first hint of trouble was relayed to Coastal Sentry Quebec after a gap in communications by Scott at 7:17:15 MET with the words "We have serious problems here," followed by the remark that Gemini 8 had already undocked with the Agena.

LM-12
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posted 09-20-2013 10:15 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
Thanks for that. The crew had time to yaw the docked Gemini and Agena vehicles 90° as planned, before the control problems began.

LM-12
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posted 09-21-2013 01:21 AM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
In this clip, you can see the EVA equipment in the Gemini 8 adapter section as the spacecraft is hoisted up to the white room at Pad 19.

jasonelam
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posted 09-21-2013 07:20 AM     Click Here to See the Profile for jasonelam   Click Here to Email jasonelam     Edit/Delete Message   Reply w/Quote
The actual time between docking and the first sign of trouble was 27 minutes. The issue was first noticed right after the Agena maneuver.

LM-12
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posted 09-22-2013 12:15 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
The Gemini 9 control system malfunction procedures from the Gemini 8 anomaly report had this EVA warning:
IF EVA, PILOT WILL REENTER S/C AS SOON AS POSSIBLE AFTER DETECTION OF MALFUNCTION. ACCOMPLISH ONLY STEPS NECESSARY FOR PILOT TO REENTER S/C OR SECURE TO THE S/C FOR TROUBLE SHOOTING. PILOT REMAIN IN SIGHT OF CMD PILOT.

LM-12
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posted 09-22-2013 06:23 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
NASA SP-4002 has the docking at 6:33:22 GET and 41:50 as the docked period.

LM-12
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posted 09-24-2013 12:01 PM     Click Here to See the Profile for LM-12     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by LM-12:
To provide EVA capability through either hatch...
I wonder if the command pilots ever trained for an EVA through the left hatch. For an EVA emergency, perhaps.

All times are CT (US)

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