Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!unixhub!stanford.edu!eos!aio!vf.jsc.nasa.gov!oliver
From: oliver@vf.jsc.nasa.gov
Newsgroups: sci.space.shuttle
Subject: Re: Airlock location on spacelab missions
Message-ID: <1991Jun11.134500.1@vf.jsc.nasa.gov>
Date: 11 Jun 91 19:45:00 GMT
References: <6369@ns-mx.uiowa.edu>
Sender: news@aio.jsc.nasa.gov (USENET News System)
Distribution: usa
Organization: NASA Johnson Space Flight Center
Lines: 28

In article <6369@ns-mx.uiowa.edu>, bheil@scout-po.biz.uiowa.edu writes:
> When flying the SpaceLab habitable module, where is the airlock located?  Since
> they are looking at the seal and insulation that came loose on the payload bay
> doors how would they exit to the payload bay to close the doors manually if
> that became neccassary?
> 
The airlock remains where it has always been, on the mid-deck.  However the "B"
hatch has been removed.  This is the hatch which normally opens into the pay-
load bay.  For spacelab flights a tunnel adapter is installed which connects
the Orbiter cabin with the spacelab module.  Near the cabin is hatch "C" which
opens up into the payload bay.  Hatch "D" is located at the spacelab end of the
tunnel, and is used to seal off the spacelab module in the event of a spacewalk 
or if the spacelab module has a pressurization problem.

Should a spacewalk become necessary, the EVA crewmembers will enter the airlock
as on a normal spacewalk closing the "A" hatch behind them.  The "D" hatch will
be closed to protect the spacelab environment.  The crew then enters the payload
bay using the "C" hatch.  The "C" hatch is sometimes visable at the bottom of 
the picture when the cameras are showing a payload bay view.

All four of the Orbiter airlock hatches are designed to seal with an atmosphere
on one side and a vacuum on the other.  Only the "D" hatch at the spacelab side
of the tunnel adapter must be able to seal with the vacuum on either side of the
hatch.
-- 

Pat Oliver -  	Lockheed Engineering and Sciences Company at NASA JSC
		OLIVER@vf.jsc.nasa.gov