Message-ID: <8a6i4Q200VcJ47X04G@andrew.cmu.edu>
Reply-To: space+@Andrew.CMU.EDU
From: space-request+@Andrew.CMU.EDU
To: space+@Andrew.CMU.EDU
Date: Thu,  5 Apr 90 02:09:33 -0400 (EDT)
Subject: SPACE Digest V11 #222

SPACE Digest                                     Volume 11 : Issue 222

Today's Topics:
			  Re: Ejection seats
			  Re: Ejection seats
			 Re: HST Image Status
		    Re: Galileo Update - 04/04/90
----------------------------------------------------------------------

Date: 5 Apr 90 01:32:24 GMT
From: usna!baldwin@uunet.uu.net  (J.D. Baldwin.)
Subject: Re: Ejection seats

In article <384@mtndew.UUCP> friedl@mtndew.UUCP (Steve Friedl) writes:
>Al Bowers writes:
>> Your 25g estimate is in the ballpark.  Older seats generated up to 40g
>> and had consequent higher injury rates.
>
>So what causes these injuries?  Hitting the ground?  Hitting the
>canopy?  Getting arms caught on something?  Sheer acceleration?
>Running into another aircraft? :-(
>
>I find it easy to believe that ejecting is not A Fun Thing, but
>where specifically is the danger?

I can only speak for the ESCAPAC seat, found in the A-4 Skyhawk (all 
variants) and the *mighty* S-3 Viking (both variants), but the max "G" is
11G.  Not too bad--the dynamic ejection simulators give you six "G" and
it barely gets your attention.

Ejection survival rates run around 80-95%, depending on the year (this is
for all seats, and represents a U.S. Navy/Marine Corps-wide figure; I suspect
USAF rates are generally higher).  Far and away the biggest killer is
waiting too long to eject, or ejecting "out of the envelope," as they say.
I have never heard of ejection into another aircraft, but have seen film
of ejections into Aircraft Carrier islands and other structures.  :-( is
right!

A straight-and-level flight, routine ejection ("routine"!?!) is really nothing
to fear, and in recent years (the last 10, I believe) has a survival rate
of 100%.  Modern seats never fail catastrophically and very, very rarely
fail at all.

Back to the S-3 for a moment:  the canopy does not jettison prior to 
ejection (it is too big)--there is a breaker bar mounted above the crewman's
head and ejection is *through* the canopy.  Ouch.  Well, it sounds like an
"ouch," anyway--I've talked to guys who've done it and they say, essentially:
"Trust me, you don't notice--or care."
--
From the catapult of:               |+| "If anyone disagrees with anything I
   _, J. D. Baldwin, Comp Sci Dept  |+| say, I am quite prepared not only to
 __||____:::)=}-  U.S. Naval Academy|+| retract it, but also to deny under
 \      / baldwin@cad.usna.navy.mil |+| oath that I ever said it." --T. Lehrer
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

------------------------------

Date: 4 Apr 90 19:19:15 GMT
From: swrinde!zaphod.mps.ohio-state.edu!usc!petunia!news@ucsd.edu  ( * * * Hunter * * * )
Subject: Re: Ejection seats


In article <384@mtndew.UUCP> friedl@mtndew.UUCP (Steve Friedl) writes:

>Al Bowers writes:
>> Your 25g estimate is in the ballpark.  Older seats generated up to 40g
>> and had consequent higher injury rates.
>
>So what causes these injuries?  Hitting the ground?  Hitting the
>canopy?  Getting arms caught on something?  Sheer acceleration?
>Running into another aircraft? :-(
>
>I find it easy to believe that ejecting is not A Fun Thing, but
>where specifically is the danger?

According to USAF statistics, (I think), the most common cause of injuries 
caused by ejecting from an aircraft are those caused by appendages becoming
temporarily attatched to part of the aircraft during ejection, (i.e. an arm
or leg getting caught on the windscreen frame, etc.)  Secondary to that is 
the injury caused by the force of ejection.

#=============================================================================#
 |\_/| mhuang@polyslo.CalPoly.EDU "PROGRAM: tr.v. To engage in a pastime       
 {O o} mhuang@FubarSys.SLO.CA.US   similar to banging ones' head against a     
 ( " )  * Ack! Ack! Pfft! Ack! *   wall, except with fewer chances for reward."
   U   (Bill the Cat has ejected many times without much brain damage.)    
 Admiral Michael "Hunter" Huang  +---<<< * * * S T A R   T R E K * * * >>>---+ 
 USS Ticonderoga, NCC-1736       +--<<< * * * * L I V E S ! ! ! * * * * >>>--+ 
#=============================================================================#

------------------------------

Date: 4 Apr 90 22:57:20 GMT
From: bu.edu!bass!ardai@eddie.mit.edu  (Michael Ardai)
Subject: Re: HST Image Status

Darn!  He posted the wrong picture.  The one with the Jovian waving at
the HST was a much better shot :-}
/mike
\|/ Michael L. Ardai     ardai@bu-pub.bu.edu   
--- ---------------------------------------------------------------
/|\ ...!sun!teda!maven.dnet!ardai (preferred)

------------------------------

Date: 5 Apr 90 04:46:44 GMT
From: agate!shelby!csli!jkl@ucbvax.Berkeley.EDU  (John Kallen)
Subject: Re: Galileo Update - 04/04/90

In article <3282@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes:
>                   GALILEO MISSION STATUS
>                        April 4, 1990
...
>....  On April 17, ultraviolet spectrometer measurements
>will be made on the star Lyman Alpha.

Eh? Isn't Lyman Alpha a wavelength? Never heard of the constellation
"Lyman" :-)

_______________________________________________________________________________
 | |   |   |    |\ | |   /|\ | John K{llen           Computer: kom-pyu'-t:r (n)
 | |\ \|/ \|  * |/ | |/|  |  | PoBox 11215            device to speed and 
 | |\ /|\  |\ * |\ |   |  |  | Stanford CA 94309      automate errors.
_|_|___|___|____|_\|___|__|__|_jkl@csli.stanford.edu__________________________

------------------------------

End of SPACE Digest V11 #222
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