From: roberts@cmr.ncsl.nist.gov (John Roberts)
Newsgroups: sci.space
Subject: Re: DC cost estimates
Date: 1 Jan 93 19:41:48 GMT
Distribution: sci
Organization: National Institute of Standards and Technology formerly National Bureau of Standards
X-Added: Forwarded by Space Digest
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU


-From: aws@iti.org (Allen W. Sherzer)
-Subject: Re: DC cost estimates
-Date: 31 Dec 92 22:35:17 GMT

-In article <C04M9F.58D.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
->I should make one additional point regarding Allen's calculations - they
->don't include the large opportunity cost if the Shuttle program should
->be cancelled before DC is fully operational 

-I con't follow this. It seems to me that if Shuttle is cancled it could
-more than double the market for DC flights. This could roughly cut DC
-costs in half.

I hope you understand what I mean by the economic term "opportunity cost".
Let me illustrate by an example from an old episode of the comic strip
"Bloom County":
  Opus the Penguin has somehow managed to obtain a military development
  contract worth several hundred billion dollars. That's great, except for
  one problem: there's no way Opus is going to be able to fulfill the terms
  of the contract within the specified timetable. Thus, for however long
  it takes the military to figure this out, they're going to be deprived of
  whatever benefit they expected to gain from the system to be developed.
  [Note 1]

Similarly, with the Shuttle as an operational, manned system with a number
of currently unique abilities, the fact that it's in use indicates that
those who pay for it (NASA, the government in general, and the public in
general) get get some value out of it. There are in fact a considerable
number of missions scheduled over the next few years. If the Shuttle program
were cancelled today, those missions would also have to be cancelled, or at
least deferred. Assuming DC will be a workable system for launching useful
payloads to LEO (which isn't *proven*, though the prospects look favorable),
and even if the program were given all the money expected to be needed for
development right now, they couldn't possibly have a system ready to launch
another TDRS in January, for instance. An extremely optimistic projection
to get one or more DCs in service, with combined payload/year comparable
to the Shuttle fleet (and keeping in mind that they'll probably be pretty
cautious on between-flight service at first) might be five or six years.
That's five or six years in which the US is without the capabilities of
the Shuttle *or* of DC - an enormous opportunity cost. Just as a few
examples, TDRSS might be reduced to one working satellite, HST might have
to shut down for a few years due to further failed gyros (or even break
down entirely), EURECA might reenter and burn up before a DC flight can
get to it to recover or reboost, and all the science missions that have
been waiting for ten or fifteen years already might have to wait another
five or ten years to get a DC berth. Time delay *does* represent a cost -
if it didn't, we could cancel all our current and planned launchers, and
start work on a really spectacular launch system, to be ready in fifty years
or so. 

Also bear in mind that many of the upcoming missions have hardware partly
or completely finished that was designed with the capabilities of the Shuttle
in mind, and it's *not* compatible with at least the initial configuration
of DC. So those missions will have to wait even longer for more advanced
"super DCs" to come along, or for DC to expand its capabilities in other
ways (i.e. in-orbit assembly), or they will have to scrap their current
hardware and rebuild for use with DC - more costs and delays.

I also have reservations about the "market" argument. Considering for 
example the market for human-tended microgravity science experiments
(by "market" I include government and university programs), I don't see
how shutting off US services for several years would help that market to
grow. Henry has described his views on the measures need to help a particular
market to grow. Price is one factor, but I believe continuous availability
of the services the market uses is also very important. I believe a number
of markets for Shuttle services disappeared due to flagging interest during
the interval between the Challenger accident and the resumption of flight,
for instance, and that was only about three years. If the capability for
human presence in space is one of the things that makes DC valuable, it
doesn't make sense to shut off US capacity to provide this capability for
several years while DC is being developed.

So while I think vigorous pursuit of DC development is a good idea, I think
cancelling the Shuttle program in the meantime is a bad idea. If DC turns
out to be as good as projections indicate, I think it will not suffer from
any lack of business (and no need to artificially double the market to get
costs even lower - that should follow naturally), but given the differences
in capabilities, I expect the Shuttle will continue to be used for a 
considerable time following the successful introduction of DC, though 
probably with different launch rate and mix of payloads.

There *are* things that should be done in the near term. Designers should
start thinking about payload designs that are compatible with both the Shuttle
and DC, so that we can start taking advantage of the benefits of DC as soon
as it's available. For instance, one might consider a standard payload
size/mass that DC can carry one of, and the Shuttle two (or perhaps two
along with a small third payload). The risk of doing that immediately rather
than waiting a year or two to implement it (as opposed to planning) is
that as I understand it, we don't really *know* what the cargo bay size
and payload mass of DC will be. It would be a terrible shame to build a
batch of 20000 pound payloads and then find out that DC can only lift
15000 pounds. Any such designs started before we have a clearer idea of
the limits should be very conservative on size and mass. (I was somewhat
surprised to hear the recent discussion by you and others that DC-X is
intended to answer relatively few of the many points that must be addressed
before DC can be operational. It's a vitally important first step, but a
step along a longer path than I had envisioned. I still think it's a good
idea, however.)

One question I'm not sure has been addressed before: is the DC-1 expected to
provide for a "shirtsleeve" environment access tube to the cargo bay, like
the Shuttle? In other words, would a "mini-Spacelab" be a viable option for
a DC-1 payload?

[Note 1]: If you'd prefer a more space-related example, consider the chilling
cautionary tale from "Monty Python", in which Mr. Angus Podgorny of Dunbar
has received an order for 48000000 kilts from the planet Skyron in the Galaxy
of Andromeda:
  Mrs. Podgorny: Angus how are y'going to get 48000000 kilts into the van?
  Angus: I'll have t'do it in two goes.
  Mrs. Podgorny: D'you not ken that the Galaxy of Andromeda is two million,
    two hundred thousand light years away?
  Angus: Is that so?
  Mrs. Podgorny: Aye... and you've never been further than Berwick-on-Tweed...
  Angus: Aye... but think o' the money dear...L18.10.0d a kilt... that's...
    L900000000 - and that's without sporrans!
[Obviously, the Blancmanges of the planet Skyron are not going to get their
order filled any time soon. They shouldn't give up their intergalactic
starship program until delivery vans are proven to be adequate to the task.]
:-)

John Roberts
roberts@cmr.ncsl.nist.gov
Newsgroups: sci.space