Newsgroups: sci.space.history
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Mercury Landing Bag Questions:
Date: Wed, 8 Jul 1998 02:35:29 GMT

In article <Pine.SUN.3.95q.980707124433.28053K-100000@swlpfa.msd.ray.com>,
Larry Deck  <lid@swlpfa.msd.ray.com> wrote:
>In the flight chronology Caidin mentions that following the peroxide dump
>the heat shield is jettisoned and the landing bag is deployed...
>Was the heat shield really jettisoned?

Sort of kind of -- the landing bag was a fabric cylinder joining the base
of the capsule proper to the heatshield.  So although the heatshield was
cut loose, it wasn't going very far.

>How was the landing bag actually deployed?  I understand that it was to
>act as a big shock absorber and I also assume that it was filled with a
>gas of some sort.

If memory serves -- it's been a long time since I read about this -- the
bag had small vents in its sides, and simply filled with air as the weight
of the heatshield dragged it open.  After splashdown, it filled with water,
and served as a sea anchor to help hold the capsule upright, I think.

>Was this system used due to weight limits?  It seems that they could have
>done away with it by simply using multiple parachute.

They were worried about the landing impact and thought this was a simple
way to cut it further.  Data from Mercury said they'd been worrying
unnecessarily, so Gemini and Apollo dispensed with the bag, although they
did do one subtle thing which gave much the same effect:  their parachute
harnesses were designed so that they came down tilted, with one edge
entering the water first.
--
Being the last man on the Moon is a |  Henry Spencer   henry@spsystems.net
very dubious honor. -- Gene Cernan  |      (aka henry@zoo.toronto.edu)