The Space Shuttle Decision Revisited
The variation of cost-effectiveness vs. flight rate is shown in Figure 2.312 – ‘break even’ for the TAOS (Thrust Assisted Orbiter Shuttle) Shuttle configuration was/is around 25 flights ... Obviously the case for the Space Shuttle system was better with additional uses in low earth orbits.
One problem: it was all a pack of lies, to put it bluntly. Or rather, it made certain assumptions: that the rate of Shuttle launch would be >25 per year, that the solid rocket boosters would be replaced by cheaper (and safer) liquid-fueled ones, that a "space tug" would be developed to service satellites at geosynchronous orbit...
The last two assumptions were not just reasonable, they were essential. The first one was known to be impossible.
That a space-tug wasn't developed, and the initial solid-fuel boosters were retained, meant that there was no case for a Shuttle any more. It was always about enhanced capability, able to do what would be otherwise impossible, not able to do the same things for less.
Also noteworthy in this context was the fairy tale of the “assumed” $5 million cost for each Shuttle launch. The range of launch costs was clearly identified in ALL reports and testimony to Congress and in three separate GAO ‘in-depth’ reviews in the 1970’s – and was stated as shown in Figure A-2.
· For TAOS with Solid Boosters (the configuration ultimately chosen by NASA) these costs ranged anywhere from $15 million to $30 million (in 1970 dollars – or about $60 to $120 millions in today’s dollars) depending on assumed launch rates of up to 24 per year, with a clearly stated launch risk of 2% (98% success rate).
· In contrast, TAOS with Liquid (Pressure Fed) Boosters would reduce these costs and risks by about half – and would permit the possibility of intact abort throughout launch.
Actual number of launches averaged 4 a year, at a cost of $1.5Bn each. Call it $400 million in 1970 dollars.
Anyway it's too late to think about more shuttle launches now. We can't get the parts any more.