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Author
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Topic: Lunar Gravity on Apollo Landing Crews
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ejectr
Member Posts: 1758
From: Killingly, CT
Registered: Mar 2002
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posted 11-10-2007 07:23 AM
   
I was just wondering, at what point in their descent to the surface did the Apollo crews first start to feel the effects of lunar gravity. |
Scott
Member Posts: 3307
From: Houston, TX
Registered: May 2001
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posted 11-10-2007 10:24 AM
They first felt "G" forces when they fired the LM's descent engine to begin the powered descent. Stable 1/6 gravity would have been felt after landing. |
FordPrefect
Member Posts: 26
From: Karlsruhe, Germany
Registered: Apr 2005
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posted 11-12-2007 06:32 PM
The average deceleration during the Lunar Module's braking and approach phase was about 3 m/s/s, which equals to about 0.3 g's |
Obviousman
Member Posts: 438
From: NSW, Australia
Registered: May 2005
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posted 11-13-2007 04:40 AM
Has anyone done the sums to confirm this? The answers gel with what I expected to happen, but I have a feeling we are missing something somewhere.Also, I am wondering if the point "...where they first start to feel the effects of lunar gravity..." might actually be at pitchover? Technically, prior to this they were feeling the effect of the DPS.... |
Saturn V
Member Posts: 176
From: Golden, Colorado, USA
Registered: Nov 2006
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posted 11-13-2007 08:48 AM
From interviews that I have listened to on the SpaceCraft Films DVDs, the astronauts reported that they did not "feel" the gravity because they were strapped down to the floor during decent to the surface or at least there was a downward force being applied by the straps. This being strapped down to the floor was in effect an artificial gravity.
Richard |
John Charles
Member Posts: 342
From: Houston, Texas, USA
Registered: Jun 2004
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posted 11-13-2007 07:43 PM
quote:
Originally posted by ejectr:
I was just wondering, at what point in their descent to the surface did the Apollo crews first start to feel the effects of lunar gravity.
As the previous answers indicate, this is a tricky question. If you mean, "when do they feel 1/6-g" then that would be shortly before landing, when the descent engine had decelerated their velocity to be essentialy zero relative to the moon and they were near the surface. During powered descent from lunar orbit down to the moon's surface, their flight path was constantly affected by the moon's gravity, but they couldn't "feel" it separate from the deceleration provided by the descent engine. (Einstein noted that the acceleration due to a rocket engine is indistinguishable from the acceleration due to gravity--they don't "feel" different, and all one "feels" is the vector sum of them both.) But the astronauts were subject to the effects of lunar gravity while in orbit around the moon, and while falling toward the moon from the Earth-Moon Equigravisphere, and even while standing on Earth (think: tides). ------------------
John Charles
Houston, Texas |
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