Access to Space: The Future of U.S. Space Transportation Systems Page: 23
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Chapter 2 Space Program Futures . 23
emergency. A crew emergency return vehicle and
the facilities to support it would add between $1
billion and $2 billion in development costs to
NASA's space transportation budget over the next
decade, plus an unknown amount of operating costs.
Option 2: Limit growth of NASA's activities for
humans in space.
This option would defer beginning construction
of the Space Station until the early part of the 21st
century and place greater near term emphasis on
space science and robotic planetary exploration. It
would require only six to eight Shuttle flights per
year and reduce NASA's need for a heavy lift launch
vehicle such as Shuttle C.
Limiting Space Shuttle flights to eight per year
would reduce space transportation costs for 1989
2010 by about $10 billion, compared to space
transportation costs for OTA's Option 1, in which
the Shuttle flight rate would increase to 12 per year
by 2005.6Probably, even more would be saved on
other NASA accounts, because 65 to 70 percent of
NASA's budget goes to support space activities
involving people in space a fraction that will
increase as Space Station funding grows.
The United States possesses the technology to
improve the capabilities of existing launch vehicles
and facilities through evolutionary modifications.
Even if overall space transportation demand fell well
below U.S. capability, the incremental improve
ment of current vehicles and facilities could
provide a low cost means to enhance U.S. launch
capabilities. Evolutionary improvements will be
most effective if they are guided by a long term
plan that includes both a concrete goal and the
steps to reach it.
Option 3: Establish a lunar base or send crews to
Mars.
On the 20th anniversary of the Apollo Moon
landing, President Bush announced his intention tosupport "a sustained program of manned explora
tion of the solar system and the permanent settle
ment of space."' His vision includes the construction
of the Space Station during the 1990s and the
establishment of a permanent lunar base, as well as
human exploration of Mars sometime in the next
century (box 2 A).
A long term program of this magnitude would
require building new heavy lift cargo systems, such
as the Shuttle C or the Advanced Launch System
now under study, or even larger ones,'and would
require new crew carrying systems. It would also
need orbital maneuvering vehicles and reusable
orbital transfer vehicles. In addition to scientific
instrumentation, crew accommodations, and propul
sion units, cargo would consist of large amounts of
fuel and supplies to support both Moon or Mars
crews and the necessary Earth orbit infrastructure. 'o
Such a program would continue the strong domi
nance of government in the development and
deployment of space infrastructure and require
considerable growth in the U.S. budget for the
civilian space program.
Option 4: Continue the trends of launching
increasingly heavier payloads and/or pursue
an aggressive Strategic Defense Initiative
(SDI) test program.
The size and weight of spacecraft for communica-
tions, navigation, reconnaissance, and weather ob
servations have been increasing slowly and have
been forcing the lift capacity of launch systems up
with them. An aggressive SDI test program would
also require vehicles of greater weight capacity than
we now possess.
Although it would be feasible to expand the lift
capacity of current launch systems to meet such
growth in payload weight, if demand is high, new,
advanced systems may be more reliable and cost
effective. This option would require moderate
growth in the Nation's capacity to launch payloads.6U.S. Congress, Office of Technology Assessment, Launch Options for the Future A Buyer's Guide, OTA-ISC-383 (Washington, DC: U.S.
Government Printing Office, July 1988). However, the average cost per launch would increase somewhat.
7PresidentGeorgeBush, Speech at the Smithsonian Institution's National Air and Space Museum, July 20,1989.
8National Aeronautics and Space Administration,Report of the 9o. Dy StudyonHuman Exploration of the Moon and Mars (Washington, DC:
November 1989), sec. 5.
9An orbital maneuvering vehicle is designed t. movepayloadsaroundin space Within a single orbit. An orbital transfer vehicle would transfer
payloads from one orbit to another, e.g., from low Earth transfer orbit to geosynchronous orbit.
11.e., orbital maneuvering and orbital transfer vehicles, and other supposing elemcnlt
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United States. Congress. Office of Technology Assessment. Access to Space: The Future of U.S. Space Transportation Systems, report, April 1990; [Washington D.C.]. (https://digital.library.unt.edu/ark:/67531/metadc39959/m1/33/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.