From: hack@arabia.uucp (Edmund Hack)
Newsgroups: sci.space
Subject: Re: Space Station Freedom assembly questions
Date: 29 Jul 1992 15:50:44 GMT
Organization: Lockheed ESC, Houston

In article <1992Jul29.141457.3965@samba.oit.unc.edu> cecil@physics.unc.edu (Gerald Cecil) writes:
>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!
>
>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(!)

The plans assume that the fleet is not grounded until PMC.  Post-PMC,
the lifeboat (which is TBD) could get the crew back.  I'm sure there are
contingency ideas on how to preserve the MTC station configuration in a
minimum drag configuration until a reboost could be done.
>
>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 never got past some early concepts.  No plans for use. It
never even got to be vaporware.
>
>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?

Payload integration could be a problem.  The reliability of Energia is
still somewhat suspect.  On one launch, the second stage failed.  Not
good. There have been only a couple launches, so there is little basis
to predict reliability.  There could be problems with things like
vibration and sonic loads in the payload carrying version.  It is tricky
to predict and then fix such items.  The Saturn program had a few early
problems with unanticipated oscillations during launch (pogoing).  It
was fixed, but cropped up in at least one manned Apollo launch, but it
was not enough to hurt the mission.  The biggest problem in assessing
the reliability and usefulness of Energia is a lack of hard data and
operational information.  This may be cured soon, as the State
Department has allowed NASA to discuss it with the Energia folks on
Goldin's recent trip to Russia. At some previous meetings of NASA and
NPO Energia staff, the Energia people brought up using the launcher.
However, under Government rules, the NASA staffers can only discuss
items that are pre-approved by the State Dept., so all they could do was
listen and take any handouts.  They couldn't ask or answer any
questions. On at least one trip, NASA was told not to discuss Energia,
when they had asked to (the SEI staff was interested).

>
>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.

Yes, it is capable of expansion.  I'm not sure of the present level of
"hooks and scars" for that.


-- 
| Edmund Hack - Lockheed Engineering & Sciences Co. - Houston, TX
| hack@aio.jsc.nasa.gov    SpokesPersonp(Me,or(NASA,LESC)) = NIL
|   **** Papoon for President! You Know He's Not Insane!! ****