Access to Space: The Future of U.S. Space Transportation Systems Page: 61
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Chapter Reducing Space System Costs .61
may fear that boosters not built to government
specifications might be too unreliable, especially for
one of-a-kind spacecraft.
Current space policy provides for the civilian
agencies to "encourage, to the maximum extent
feasible, a domestic commercial launch industry by
contracting for necessary ELV launch services
directly from the private sector or with DoD."
Extending this policy to all Government
launches, both civilian and military, except those
on the Space Shuttle, could also save the Govern
ment money, but only if Government oversight
and paperwork were reduced.
The Federal Government might encourage the
private sector launch industry by issuing space
transportation vouchers to space scientists whose
experiments are being supported by the govern
ment.6These vouchers could be redeemed for
transportation on any appropriate U.S. launch vehi
cle, and would free scientists to choose the vehicle
they thought most suitable to the needs of the
spacecraft. This policy would free space scientists
from dependence on the Shuttle and its schedule. It
might also increase opportunities for researchers to
reach space. By reducing scientist's dependence on
the Shuttle, such a policy should help in raising the
demand for ELVs and in bringing down the cost of
space transportation.
PAYLOADS
Dramatic reductions in launch costs will not,
by themselves, lower spacecraft program costs
substantially, because it may cost from $40,000 to
$650,000 per pound to design and build many
payloads, while it costs only about $3,000 per
pound to launch one to LEO. Reducing launch
costs to $300 per pound, a goal of the ALS program,8
may reduce the total cost of procuring and launching
an expensive spacecraft by less than 2 percent.
Commercial communications satellites, however,
often cost on the order of $10,000 per pound.
Because they need to be placed in geosynchronousorbit, which is more expensive to achieve than LEO,
the cost of a launch is comparable to the cost of the
payload. Therefore, commercial operators are ex
tremely interested in cost reductions in both areas.
To reduce payload costs, and for other reasons,
novel approaches to payload design and fabrication
have been proposed:
* Provide for Weight Margin: Designing pay
loads to fit launch vehicles while reserving
ample size and weight margins can reduce the
risk of incurring delay and expense after
assembly has begun.
Satellites often grow substantially heavier
than expected as they proceed from design to
construction. If a payload grows so heavy that
its weight equals or exceeds the maximum
allowable gross lift off weight, the payload
must be redesigned, which causes delay and
increases cost. To reduce the risk of exceeding
vehicle payload capacity, program managers
could require designers to allow extra weight
margin for such contingencies. However, this
design philosophy would lead to more stringent
size and weight constraints than would other
wise be imposed. In many cases, sufficient
margin could be provided by clever design,
e.g., by designing several smaller single
mission payloads, to be launched separately,
instead of a single multimission payload.
* Fatsats: If payloads were allowed to be heavier
for the same capability, some could cost
substantially less. For example, OTA estimates
that Titan class payloads that cost several
hundred million dollars might cost about $130
million less if allowed to be five times as heavy.
If payloads were allowed to be much heavier, a
manufacturer could forego expensive processes
for removing inessential structural material, as
well as expensive analyses and tests. Standard
ized subsystems, which could be produced
economically in quantity, could be used instead
of customized subsystems. Designers could
also add redundant subsystems to increase5White House, Office of the press Secretary, "National Space Policy," Nov. 2, 1989,P. I.
6Molly Macauley, "Launch Vouchers for Space Science Research," Space Policy, vol 5, No.4,pp. 311 320.
Thelow end of this range is for payloads consisting mostly of fuel; the high end would be for some satellites carrying little or no fuel. U.S. Congress,
Office of Technology Assessment, Affordable Spacecraft: Design and Launch Alternatives ackground Paper, OTA-BP-ISC-60 (Washington, DC:
U.S. Government Printing Office, January 1990).
8101 stat. 1067.
9he number of new program starts allowed in a year tends to force program managers to add additional capabilities to the spacecraft. In addition,
in some cases, a larger spacecraft bus can accommodate more functions at a reduced cost per function compared to multiple smaller buses.
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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/m1/64/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.