From: seds%cspara.decnet@Fedex.Msfc.Nasa.Gov
Subject: Re: Space Station Freedom assembly questions
News-Software: VAX/VMS VNEWS 1.41    
Organization: University of Houston
Date: Wed, 29 Jul 1992 18:14:00 GMT

In article <1992Jul29.141457.3965@samba.oit.unc.edu>, cecil@physics.unc.edu (Gerald Cecil) writes...
>(Reformatted to be more readable, sorry.)
>I'm trying to formulate a letter on the Space Station to my Congresspeople.
>I have several questions on Space Station assembly issues that I'd 
>appreciate some input on.  Thanks in advance!

Not a correct number. JR Tompson in congressional testimony stated that there
is a very good chance of losing an orbiter during the space station assembly 
process (for full outfitting and ten years of flights) This is about one in 50
probability or one in 70 for the current schedule. We have had 24 flights
since Challenger, the same amount as before Challenger and it *seems* that 
the program is far more on schedule and many of the criticality one problems
have been fixed since Challenger (APU's have been targeted as the most 
dangerous problem to shuttle safety and have been extensively redesigned)

>1. What is the current thinking on Shuttle accident probabilities and the 
>impact on Space Station assembly?  I recall reading of an Air Force 
>assessment Post-Challenger that compounded to near certainty of a 
>disabling accident in 20 flights.  (Not necessarily an explosion, but at 
>least removal of an Orbiter from the fleet.) If this is generally accepted, 
>but not discussed, maybe it needs some airing here(!)
> 


>2. What is the status of Shuttle-C?  Is it supposed to play any role in 
>Station assembly or for logistical support (= hauling water & hydrazine)?

Shuttle C is dead. The mockup here at Marshall has been dissassembled and
no further studies have been planned.  All of our current heavy lift eggs are
going with NLS.

> 
>3. The only NON-POLITICAL argument that I have heard as to why Space 
>Station components should NOT be launched on Energia is the comparatively 
>northern latitude of the launch site and consequent payload loss for 
>cross-plane maneuvers.  The penalty in my estimation doesn't look that bad, 
>given the large intrinsic capability of Energia, so are there
>obvious bona-fide TECHNICAL problems (e.g. no engine restart capability)
>that someone might care to comment on?
> 

The cross plane maneouver from 51 degrees down to 28.5 degrees has an 
enormous penalty in payload.  This is why you will NEVER see a Soyuz at
SSF orbit unless it is on Energia.  The payload penalty will drop Energia's
delivered payload to around 50,000 pounds.  I do not know the dynamics and 
this estimate is based on what I have read in generalities regarding that 
Energia could at best only deliver a Soyuz to SS Freedom. Anybody have 
Delta V numbers for such a plane change?

>4. Does the present baseline Station have any real prospects for expansion?  
>I'm thinking of intrinsic power or dynamic (structural) compromises that 
>would prohibit additional modules.

There is essentially no limit to the possibilites for expansion with the 
open truss architecture of SS Freedom.  This was one of the FUNDAMENTAL
design drivers for this architecture.  It may not have all of the 
capabilities that we want now, but it can expand to accomodate much more
power, internal Hab area and so forth.  

Note the problems that they are having with stabilization and reboost 
currently with MIR.  The spam in a can approach to Space stations and
the adding of modules such as has been the case with MIR has led to severe
problems in control requiring the flight we read of right now to continue
to fix the stabilization system and add new propulsion.

For more information ask Bill Higgins here for a copy of Gordon Woodcock's
paper on SS Freedom presented at the 1989 ISDC conference that aged Bill
at least a year or two.  Hope you still have some of that stuff Bill.

Dennis, Wingo University of Alabama in Huntville

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Revive the Saturn V!
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Saturn Configuration		#F1A engines	#STME engines Payload to LEO

S1C-1 				1		1		50,000 lbs
S1C-2 Common tankage w/S1C-1	2		1 or 2		110,000 lbs

Common tankage for next phase

S1C-3				3		2		180,000 lbs
S1C-4				4		2 or 3		235,000 lbs
S1C-5 Full Saturn V config	5		5 plus 1 s/3	305,000 lbs
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