Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucsd!ucbvax!ITI.ORG!aws
From: aws@ITI.ORG ("Allen W. Sherzer")
Newsgroups: sci.space
Subject: Re: Reliability and Insurance (2 of 3)
Message-ID: <9011150330.AA04966@iti.org>
Date: 15 Nov 90 03:30:00 GMT
References: <1565.27401C39@ofa123.fidonet.org>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: Evil Geniuses for a Better Tomorrow
Lines: 125

In article <1565.27401C39@ofa123.fidonet.org> Wales Larrison writes:
>    However, this does pose some interesting questions.  If, as you 
>say, the Delta HLV design is 7 Deltas strapped together, does this 
>not imply the reliability to be .98^7 = .86?  

No the claimed reliability is much higher. A failure which is
catostrophic with one Delta may not be as bad if there are six
others to take up the slack.

I have seen figures on HL Delta reliability but cannot state
them here. The reliability is near Shuttle levels although I
do not know how the figure was arrived at.

>Also, looking at the 
>historical data shows that a significant design change to a launcher 
>typically results in a pattern of failure for a few years (shown in 
>Delta and Scout upgrades, and in the little bit of data I have on 
>Titan history).  How do we avoid the "infant morality" for a major 
>design change to a HLV?

Maybe we don't. I don't know the answer. I do know that:

1. It will cost less than one Shuttle flight to develop the hardware
and find out.

2. For HL Delta we aren't making big changes but using well established
engineering methods.

Maybe you're right. Maybe all we get out of this is a way to send up
bulk supplies for a quater the cost of a Shuttle flight. On the other
hand, for a very small investment we just might reduce the cost to orbit
for everybody by an order of magnitude. Isn't it worth the risk?

>    For discussion sakes, lets say .90 for the new, untested HLV, 
>and .98 from the shuttle. 

Again, this does not agree with the MDAC figures.

>   2) The difference in launch costs.   I will accept the Shuttle is 
>never get the economies of scale per individual launch available in 
>a HLV.  So the price of an individual shuttle launch will be always 
>higher ($/lb) than a HLV.  However, if we can increase the shuttle 
>annual flight rate from 4 to the planned 12, then the cost is 
>reduced by $2.3 B.  

This is *VERY* unrealistic. This is three times the average launch
rate for the last *TEN YEARS*. There is no reason to think this
can be achieved.

BTW, a report in this weeks Avation week said NASA is backing off from
claiming high launch rates. There is a good graph of NASA launch
rate claims and actual for the last ten years.

>     Similarly, your HLV costs can be claimed as very opimistic. If, 
>LLNL is going to pay for a Space Station to completely recover the 
>development and financing costs for a HLV, and there is no long-
>term recurring market, I think the cost could be increased.  

I'll accept your HLV launch cost for the sake of arguement. However,
I point out that LLNL will be buying ~24 of these launches plus
more for later phases. One byproduct of this may well be enough
of an infastructure to get a real space industry started.

>   3) Engineering for assembly in orbit.  I would assume the 
>provisions needed to assemble something on orbit are the connections 
>be simple and very easy to do/undo via EVA.  

I don't think so. Just because something has field replaceable units
doen't make construction easy. For example, it may be possible to
fix the wing of a 747 at Podunk Regional Airport but that doens't
mean they could build one if given the parts.

The Zenith Star engineers considered sending the payload up on
a Titan and the Shuttle and doing assembly in orbit. This was
considered too expensive because of design changes needed. That
is why they went with the HL Delta and Titan V.

>between the two. 
>    Combining all this, gives a set of revised numbers... 
> 
>Item            HLV          Shuttle
>Payload         $22.5  B       $22.5   B
>Insurance       $ 2.250        $ 0.450 
>Launch cost     $ 0.195        $ 1.175  
>EVA             $ 0.0          $ 0.002 
>Engineering     $ 0.0          $ 0.0       Same between the two
>                --------       ---------
>                 24.945         24.017
>     Which has now reversed.... 

These two numbers are within 4% of each other. I consider that a
wash. So if we use pesamistic numbers on the HLV and optimistic
numbers on Shuttle they look the same. On the other hand, if we
can't tripple the number of Shuttle flights and MDAC is correct
on HL Delta reliability, the HLV will be the clear winner.

It will only cost us one Shuttle flight to find out.

>I would say the most sensitive part 
>of this calculation is reliability since Shuttle total costs come 
>out cheaper is HLV reliability is .94 or less (shuttle at .98).
>Based upon the historical patterns for launch vehicle development, 
>this might be a reasonable bet. 

Agreed.

>     Anyway, I think we've beat this subject to death.  Can we agree 
>to disagree on this?  My opinion is that we need a HLV capability, 
>and I think it would make sense to apply such to any Space Station 
>program - after a good test period (10-20 flights).  I'm just not as 
>hard over on killing our current programs in favor of untested new 
>programs - without a much better examination of what this entails.  
>But I support activities to examine this option. 

I can live with this. I wouldn't kill the Shuttle without having
an option in place. I just point out that there is a good chance
that that option is here.

  Allen

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