Author Topic: Lunar Module Gravity  (Read 416 times)

Offline BDL

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Lunar Module Gravity
« on: December 16, 2018, 12:06:33 AM »
I have a question about the Lunar Module’s gravity.
In lunar orbit the astronauts should be weightless. But did they operate the Lunar Module in weightlessness? And did they do it during the landing, too? Or was there something inside the Lunar Module that kept them in place?
“One small step for [a] man, one giant leap for mankind.” - Neil Armstrong, 1969

Offline Allan F

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Re: Lunar Module Gravity
« Reply #1 on: December 16, 2018, 12:38:59 AM »
They were strapped to the floor by 4 straps each, standing upright in front of their instruments.

http://heroicrelics.org/info/lm/lm-restraint-equipment.html
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Offline Dalhousie

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Re: Lunar Module Gravity
« Reply #2 on: December 16, 2018, 10:15:13 PM »
They were strapped to the floor by 4 straps each, standing upright in front of their instruments.

http://heroicrelics.org/info/lm/lm-restraint-equipment.html

Were there not also velcro strips on the floor?

Offline Kiwi

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Re: Lunar Module Gravity
« Reply #3 on: December 17, 2018, 08:06:21 AM »
Speaking of gravity in the Lunar Module, note the errors in the following excerpts from newspaper articles about Apollo 11. The reporters couldn't get their heads around the idea of the astronauts being weightless and therefore floating through the tunnel instead of crawling.

Nasa probably simply said they would enter the LM or re-enter the CM, and the reporters had to spice it up with the wrong term.

Manawatu Evening Standard,  Wednesday 16 July 1969, page 8
Apollo flight plan step-by-step

   Mr Walter Froehlich, a United States writer specialising in science, traces the Apollo-XI flight schedule.
Landing on moon
   Two of the astronauts — Apollo-XI commander Neil A. Armstrong and lunar module pilot Edwin E. Aldrin — crawl through a tunnel into the lunar module, detach it from the main craft and descend with it to the moon while their colleague, astronaut Michael Collins, remains in moon orbit in the main craft.  After checking their craft to ensure it has remained undamaged in the landing, the astronauts rest for several hours before leaving the craft to walk on and explore the moon's surface.
Exploring lunar surface
   Astronaut Armstrong leaves the lunar module and becomes history's first man to step on the moon.  The flight is now in its fourth day.  He is joined about 30 minutes later by Aldrin, who becomes the second man on the moon.  They collect rocks and other samples of moon material, take photographs of the scene and set up a television camera for live transmissions to earth.
Goodbye to the moon
   After about three hours of work on the moon's surface, the astronauts return to the lunar module and, after a few hours of rest, boost themselves with it back into moon orbit to rejoin the main craft.
   The moon visitors have been away from the craft for about a day. Armstrong and Aldrin crawl back through the tunnel into the main craft, bringing with them the moon samples and the solar wind experiment.


Manawatu Evening Standard,  Saturday 19 July 1969, page 1
Apollo readies for landing

NZPA  Space Centre, Houston, July 18
   The relaxed pace of Apollo-XI's cruise to the moon quickened today as the astronauts started preparing their fragile moon lander to make history.
   With the gravity pull of their home planet loosening with every second of their outward journey, the Apollo commander, Neil Armstrong, and Air Force Col. Edwin E. Aldrin crawl through a narrow tunnel later today from the command ship into the attached lunar lander.
   They are to check the systems of the moon machine, inspect it for launch damage, and ready it to carry them to the first manned moon landing on Sunday.


The West Australian,  Monday 21 July 1969, page 1
Apollo astronauts ready for descent to moon

   The American astronauts in Apollo 11 were orbiting the moon last night while final preparations were being made for the descent to the lunar surface early today.
   The lunar module Eagle, containing Neil Armstrong (38) and Col. Edwin Aldrin (39), was due to separate from the command ship at 1:43 a.m. (W.A. time).  The Eagle was due to start its descent at 3:07 a.m. and touch down in the Sea of Tranquility at 4:16 a.m. while the command ship piloted by Lieut-Col. Michael Collins remained in lunar orbit.
   The time when Armstrong will climb down from the module and walk on the moon surface is uncertain.  Though scheduled to begin at 2:16 p.m., after a four-hour rest period for the astronauts, the walk may be advanced by up to 3½ hours.
Transfer
   The final preparations for the descent began at 9:20 o'clock last night when Aldrin crawled through a 30in. tunnel into the lunar module.  He made the transfer at end of the space craft's tenth orbit of the moon.  Armstrong joined Aldrin about an hour later, and together they activated and checked the intricate systems of the craft.  They reported no problems and said that they were about 30 minutes ahead of schedule.
   Apollo 11 went into lunar orbit soon after 1 a.m. yesterday.  The manoeuvre was carried out while the space craft was behind the moon and out of radio contact with ground control for the first time since blast-off from Cape Kennedy last Wednesday.

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Offline Zakalwe

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Re: Lunar Module Gravity
« Reply #4 on: December 17, 2018, 09:19:07 AM »
They were strapped to the floor by 4 straps each, standing upright in front of their instruments.

http://heroicrelics.org/info/lm/lm-restraint-equipment.html

Were there not also velcro strips on the floor?

Yes, there were Velcro strips on the floor with matching strips on the soles of the boots. They also had hydraulically damped armrests to absorb any force or shocks from the upper torso.

 

"The restraint system that evolved (fig. 2) includes (1) Velcro on the boot soles and the LM floor, (2) restraint cables (from a constant-force reel) attached to the crewman to produce a constant 15-pound downward force on each side of the crewman, and (3) a set of armrests to absorb loads from the crewman's upper torso. The restraint armrests are equipped with hydraulic dampers for energy absorption. Downward forces from the middle and lower torso are intentionally absorbed by the crewman's legs. The panel handholds and the armrests are designed to supply lateral support. The constant-force reel is equipped with a cable lock to restrain the upward motion of the crewman during the lunar landing."

Source: Page 5 of this Apollo Experience Report
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Offline Dalhousie

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Re: Lunar Module Gravity
« Reply #5 on: December 18, 2018, 01:51:17 AM »
They were strapped to the floor by 4 straps each, standing upright in front of their instruments.

http://heroicrelics.org/info/lm/lm-restraint-equipment.html

Were there not also velcro strips on the floor?

Yes, there were Velcro strips on the floor with matching strips on the soles of the boots. They also had hydraulically damped armrests to absorb any force or shocks from the upper torso.

 

"The restraint system that evolved (fig. 2) includes (1) Velcro on the boot soles and the LM floor, (2) restraint cables (from a constant-force reel) attached to the crewman to produce a constant 15-pound downward force on each side of the crewman, and (3) a set of armrests to absorb loads from the crewman's upper torso. The restraint armrests are equipped with hydraulic dampers for energy absorption. Downward forces from the middle and lower torso are intentionally absorbed by the crewman's legs. The panel handholds and the armrests are designed to supply lateral support. The constant-force reel is equipped with a cable lock to restrain the upward motion of the crewman during the lunar landing."

Source: Page 5 of this Apollo Experience Report

Thanks!