 |
| Please scroll down the results page when search is completed. |
|
|
|
|
|
 |
 |
Knowns and Unknowns in Exploration: Then and Now
Editor's Note: This is the fourth in a series of
essays on exploration by Steven J. Dick.
How
realistic is the new space exploration vision to go to the Moon, Mars and
beyond? In light of current problems in the world, and budget problems at home,
some have framed the goal as undesirable, or even undoable.
At ceremonies
marking the 35th
anniversary of the Apollo 11 Moon landing on July 20, Neil Armstrong
addressed the question of the "doability" of the current Moon, Mars and Beyond
initiative. When President Kennedy proposed Apollo, Armstrong suggested, the
"unknowns vastly exceeded the knowns." President Bush, he continued, has
"challenged Americans to once more reinvigorate the exploratory nature of
Americans that has served us so well throughout history. The unknowns today are
far fewer than they were four decades ago."
 Image above: Armstrong salutes NASA
employees during his remarks at a celebration of the 35th anniversary of the
Apollo 11 landing in 2004. Photo credit: NASA/Bill Ingalls.
Armstrong's view of fewer unknowns today, even though the new
space exploration vision includes not only the Moon, but also Mars and beyond,
is grounded in history from many points of view, including science, technology
and management. When asked about Armstrong's comments from a science point of
view, Apollo project veteran Donald Beattie, who was in charge of the lunar
science experiments, recalled the following:
1) At the beginning of Apollo, there was genuine concern that a lunar
lander would sink into a deep fluffy dust layer. That was resolved by the
Surveyor landers.
2) It was thought that the gravity figure of the Moon
would disturb the Lunar Module and Command and Service Module orbits, and make
it difficult to target landing sites. That was resolved by the Lunar Orbiter
program.
3) It was thought that dangerous pathogens might result in back
contamination when the astronauts returned. That was resolved by the Lunar
Receiving Laboratory.
4) Simulations of astronaut movement in one-sixth
gravity were not very good. This was resolved only with Apollo 11 itself.
5) There was concern about visibility on the surface of the Moon,
especially in shadows, again resolved by Apollo 11. In Beattie's opinion,
there are no comparable unknowns in a return to the Moon today. As for Mars,
over the last four decades, a flotilla of spacecraft has visited the planet,
giving us an increasingly sophisticated view of what is in store when humans
land there. For a human trip to Mars, Beattie believes the biggest unknown is
whether there are dangerous pathogens. The Apollo experience will be useful, and
astronaut return will probably be handled similar to Apollo -- isolation of
material and astronauts until studied.
Moreover, prior to a human
landing on Mars, NASA's planetary protection office has established strict
protocols for a Mars sample return. Another concern is how long it will take
astronauts to adjust after six months in zero G and be able to perform their
tasks. Some data is available from Mir and other space stations since Apollo,
and more data will be collected on the International Space Station -- a resource
not available in the Apollo era.
| "If there were no unknowns, it would not be
exploration, and there is little progress, and little satisfaction, in
solving easy problems." -- Apollo 11 Commander Neil Armstrong on
The Vision for Space Exploration | In the technology
arena, Armstrong's thesis also rings true. The Mercury, Gemini and Apollo
spacecraft, along with their Russian counterparts, were the first human
spacecraft ever designed, and they were built with numerous major unknowns. The
new space vision will build on this experience to construct more multi-purpose
Crew Exploration Vehicles. The Saturn V launch vehicle had to be developed by
the von Braun team from wartime missile technology. The current space
exploration vision will require new heavy lift launch capabilities, but we know
orders of magnitude more today about launch technology than in the 1960s.
The Apollo Guidance Computer was the first to make use of integrated
circuits, and NASA's use of ICs helped make the integrated circuit commercially
viable. Eldon Hall, the leader of the hardware design efforts for Apollo
Guidance Computer, vividly recalls how that computer was put together from
scratch. And we all recall how Armstrong set down the Eagle on the surface of
the Moon low on fuel, with seconds to spare as an overloaded computer called out
error messages. Anyone with a desktop computer -- considerably more power than
the Apollo astronauts had on their way to the Moon -- can testify that computer
technology today is worlds away from the 1960s.
Historian Stephen B.
Johnson has argued that the secret of Apollo was management, without which the
technology would not have been effectively harnessed, and the science never
deployed. Today we have much more experience with large-scale high risk
technology projects, both on Earth (nuclear reactors) and in space (the
International Space Station), and historians have studied how scientists and
engineers created the systems management processes to coordinate large-scale
technology development. No one wants the return to the Moon and the first human
journey to Mars to be a race; that is another lesson of history. But we can
learn much from the Apollo management experience.
 Image above: "One giant leap for
mankind." Armstrong climbs down the lunar module Eagle's ladder as an estimated
worldwide television audience of half a billion looks on. Photo credit:
NASA.Click for larger image
There is a final insight from
history. The Apollo era was undertaken in an era of intense cooperation with the
Soviet Union, indeed, that competition was the primary driver. Today we are
presented with an opportunity for international cooperation, having had the
experience of the Apollo-Soyuz Test Project, Shuttle-Mir, and the International
Space Station. The United States need not go it alone on the road to Mars. This
not only makes the space exploration vision "doable," it also makes it a
potential instrument of world peace through international
cooperation.
All of this suggests that we are better prepared now to go
to the Moon and Mars than we were to land on the Moon in the Apollo era. This is
not to say that challenges do not remain across the board. As Armstrong said in
his 35th anniversary remarks, "Substantial unknowns do remain. But we can learn
their secrets, and find solutions to the problems they pose. Indeed, if there
were no unknowns, it would not be exploration, and there is little progress, and
little satisfaction, in solving easy problems."
Apollo today is almost
universally seen as the greatest achievement of the 20th century, despite
numerous other achievements ranging from computers to civil rights. The judgment
of history is that we have no cause to regret the Apollo program, although it
was costly and undertaken at one of the most tumultuous decades in recent world
history.
There will always be problems in the world, and budget problems
at home, and we must find ways to address them. Meanwhile I am willing to bet
that history will also judge that we have no cause to regret a return to the
Moon, and a human journey to Mars and beyond. No nation can long afford to
sacrifice long-term goals for short-term needs.
Readings
Donald A. Beattie, Taking Science to the Moon: Lunar
Experiments and the Apollo Program (NASA History Series, Johns Hopkins
University Press: Baltimore and London, 2001).
Eldon C. Hall, Journey
to the Moon: The History of the Apollo Guidance Computer (AIAA: Reston, Va.,
1996).
Stephen B. Johnson, The Secret of Apollo: Systems Management in
American and European Space Programs (NASA History Series, Johns Hopkins
University Press, 2002).
|
|
|
|
