- Dewar, James with Robert Bussard.
The Nuclear Rocket.
Burlington, Canada: Apogee Books, 2009.
ISBN 978-1-894959-99-5.
-
Let me begin with a few comments about the author attribution of
this book. I have cited it as given on the copyright page, but
as James Dewar notes in his preface, the main text of the book
is entirely his creation. He says of Robert Bussard, “I
am deeply indebted to Bob's contributions and consequently list
his name in the credit to this book”. Bussard himself
contributes a five-page introduction in which he uses,
inter alia,
the adjectives “amazing”, “strange”,
“remarkable”, “wonderful”, “visionary”,
and “most odd” to describe the work, which he makes clear
is entirely Dewar's. Consequently, I shall subsequently use “the
author” to denote Dewar alone. Bussard died in 2007,
two years before the publication of this book, so his introduction
must have been based upon a manuscript. I leave to the reader to judge the
propriety of posthumously naming as co-author a
prominent individual who did not write a single word of the main text.
Unlike the author's earlier
To the End of the Solar System (June 2008),
which was a nuts and bolts history of the U.S. nuclear rocket
program, this book, titled The Nuclear Rocket,
quoting from Bussard's introduction, “…is not really
about nuclear rocket propulsion or its applications to space
flight…”. Indeed, although some of the nitty-gritty of
nuclear rocket engines are discussed, the bulk of the book is
an argument for a highly-specific long term plan to transform
human access to space from an elitist government run program to
a market-driven expansive program with the ultimate goal of
providing access to space to all and opening the solar system to
human expansion and eventual dominion. This is indeed ambitious
and visionary, but of all of Bussard's adjectives, the one that sticks
with me is “most odd”.
Dewar argues that the
NERVA B-4 nuclear
thermal rocket core, developed between 1960 and 1972, and
successfully tested on several occasions, has the capability,
once the “taboo” against using nuclear engines in
the boost to low Earth orbit (LEO) is discarded, of revolutionising
space transportation and so drastically reducing the cost per
unit mass to orbit that it would effectively democratise access to
space. In particular, he proposes a “Re-core” engine
which, integrated with a liquid hydrogen tank and solid rocket
boosters, would be air-launched from a large cargo aircraft such
as a
C-5, with the
solid rockets boosting the nuclear engine to around 30 km
where they would separate for recovery and the nuclear engine engaged.
The nuclear rocket would continue to boost the payload to
orbital insertion. Since the nuclear stage would not go critical
until having reached the upper atmosphere, there would be no
radioactivity risk to those handling the stage on the ground prior
to launch or to the crew of the plane which deployed the rocket.
After reaching orbit, the payload and hydrogen tank would be separated,
and the nuclear engine enclosed in a cocoon (much like an
ICBM reentry vehicle) which would de-orbit and eventually land at
sea in a region far from inhabited land. The cocoon, which would float
after landing, would be recovered by a ship, placed in a radiation-proof
cask, and returned to a reprocessing centre where the highly radioactive
nuclear fuel core would be removed for reprocessing (the entire launch to
orbit would consume only about 1% of the highly enriched uranium in the
core, so recovering the remaining uranium and reusing it is essential
to the economic viability of the scheme). Meanwhile, another never
critical core would be inserted in the engine which, after inspection of
the non-nuclear components, would be ready for another flight. If
each engine were reused 100 times, and efficient fuel reprocessing
were able to produce new cores economically, the cost for each
17,000 pound payload to LEO would be around US$108 per pound.
Payloads which reached LEO and needed to go beyond (for example, to
geostationary orbit, the Moon, or the planets) would rendezvous with
a different variant of the NERVA-derived engine, dubbed the
“Re-use” stage, which is much like Von Braun's
nuclear
shuttle concept. This engine, like the original NERVA, would be
designed for multiple missions, needing only inspection and refuelling
with liquid hydrogen. A single Re-use stage might complete 30 round-trip
missions before being disposed of in deep space (offering “free
launches” for planetary science missions on its final trip into the
darkness).
There is little doubt that something like this is technically
feasible. After all, the nuclear rocket engine was extensively
tested in the years prior to its cancellation in 1972, and NASA's
massive resources of the epoch examined mission profiles (under the
constraint that nuclear engines could be used only for
departure from LEO, however, and without return to Earth) and
found no show stoppers. Indeed, there is evidence that the nuclear
engine was cancelled, in part, because it was performing so well
that policy makers feared it would enable additional costly
NASA missions post-Apollo. There are some technological
issues: for example, the author implies that the recovered
Re-core, once its hot core is extracted and a new pure uranium
core installed, will not be radioactive and hence safe to handle
without special precautions. But what about neutron activation
of other components of the engine? An operating nuclear rocket
creates one of the most extreme neutronic environments outside
the detonation of a nuclear weapon. Would it be possible to choose
materials for the non-core components of the engine which would
be immune to this and, if not, how serious would the induced
radioactivity be, especially if the engine were reused up to
a hundred times? The book is silent on this and a number of other
questions.
The initial breakthrough in space propulsion from the first generation
nuclear engines is projected to lead to rapid progress in optimising
them, with four generations of successively improved engines within a
decade or so. This would eventually lead to the development of a
heavy lifter able to orbit around 150,000 pounds of payload per flight
at a cost (after development costs are amortised or expensed) of
about US$87 per pound. This lifter would allow the construction of
large space stations and the transport of people to them in
“buses” with up to thirty passengers per mission. Beyond
that, a nuclear single stage to orbit vehicle is examined, but there
are a multitude of technological and policy questions to be resolved
before that could be contemplated.
All of this, however, is not what the book is about.
The author is a passionate believer in the proposition that opening
the space frontier to all the people of Earth, not just a few
elite civil servants, is essential to preserving peace, restoring
the optimism of our species, and protecting the thin biosphere of
this big rock we inhabit. And so he proposes a detailed structure
for accomplishing these goals, beginning with “Democratization
of Space Act” to be adopted by the U.S. Congress, and the
creation of a “Nuclear Rocket Development and Operations
Corporation” (NucRocCorp), which would be a kind of private/public
partnership in which individuals could invest. This company could
create divisions (in some cases competing with one another) and
charter development projects. It would entirely control space
nuclear propulsion, with oversight by U.S. government regulatory
agencies, which would retain strict control over the fissile
reactor cores.
As the initial program migrated to the heavy lifter, this structure
would morph into a multinational (admitting only “good”
nations, however) structure of bewildering (to this engineer)
bureaucratic complexity which makes the United Nations look like
the student council of
Weemawee High. The lines of responsibility
and power here are diffuse in the extreme. Let me simply cite
“The Stockholder's Declaration” from p. 161:
Whoever invests in the NucRocCorp and subsequent Space Charter
Authority should be required to sign a declaration that commits
him or her to respect the purpose of the new regime, and conduct
their personal lives in a manner that recognizes the rights of
their fellow man (What about woman?—JW). They must be made
aware that failure to do so could result in forfeiture of their
investment.
Property rights, anybody? Thought police? Apart from the manifest
baroque complexity of the proposed scheme, it entirely ignores
Jerry Pournelle's
Iron
Law of Bureaucracy:
regardless of its original mission, any bureaucracy will eventually
be predominately populated by those seeking to advance the interests of
the bureaucracy itself, not the purpose for which it was created. The
structure proposed here, even if enacted (implausible in the extreme)
and even if it worked as intended (vanishingly improbable), would
inevitably be captured by the Iron Law and become something like, well,
NASA.
On pp. 36–37, the author likens attempts to stretch
chemical rocket technology to its limits to gold plating a nail
when what is needed is a bigger hammer (nuclear rockets). But
this book brings to my mind another epigram: “When all
you have is a hammer, everything looks like a nail.” Dewar
passionately supports nuclear rocket technology and believes that
it is the way to open the solar system to human settlement. I
entirely concur. But when it comes to assuming that boosting people
up to a space station (p. 111):
And looking down on the bright Earth and into the black
heavens might create a new perspective among Protestant,
Roman Catholic, and Orthodox theologians, and perhaps lead
to the end of the schism plaguing Christianity. The same might
be said of the division between the Sunnis and Shiites in
Islam, and the religions of the Near and Far East might benefit
from a new perspective.
Call me cynical, but I'll wager this particular swing of the
hammer is more likely to land on a thumb than the intended nail.
Those who cherish individual freedom have often dreamt of a
future in which the opening of access to space would, in the words of
L. Neil Smith, extend
the human prospect to “freedom, immortality, and the
stars”—works
for me. What is proposed here, if adopted, looks more like, after
more than a third of a century of dithering, the space frontier being
finally opened to the brave pioneers ready to homestead there, and
when they arrive, the tax man and the all-pervasive regulatory state
are already there, up and running. The nuclear rocket
can expand the human presence throughout the solar system.
Let's just hope that when humanity (or some risk-taking subset of it)
takes that long-deferred step, it does not propagate the soft tyranny
of present day terrestrial governance to worlds beyond.
October 2009 