The science of nanotechnology could lead to
radical improvements for space exploration.
by Patrick L Barry
When it comes to taking
the next "giant leap" in space exploration, NASA is thinking
small - really small.
In laboratories around
the country, NASA is supporting the burgeoning science of nanotechnology.
The basic idea is to learn to deal with matter at the atomic scale
- to be able to control individual atoms and molecules well enough
to design molecule-size machines, advanced electronics and "smart"
If visionaries are
right, nanotechnology could lead to robots you can hold on your
fingertip, self-healing spacesuits, space elevators and other fantastic
devices. Some of these things may take 20+ years to fully develop;
others are taking shape in the laboratory today.
Image by artist Pat Rawling.
could provide the very high-strength, low-weight fibers
that would be needed to build the cable of a "space
Simply making things
smaller has its advantages. Imagine, for example, if the Mars rovers
Spirit and Opportunity could have been made as small as a beetle,
and could scurry over rocks and gravel as a beetle can, sampling
minerals and searching for clues to the history of water on Mars.
Hundreds or thousands of these diminutive robots could have been
sent in the same capsules that carried the two desk-size rovers,
enabling scientists to explore much more of the planet's surface
- and increasing the odds of stumbling across a fossilized Martian
is about more than just shrinking things. When scientists can deliberately
order and structure matter at the molecular level, amazing new properties
An excellent example
is that darling of the nanotechnology world, the carbon nanotube.
Carbon occurs naturally as graphite - the soft, black material often
used in pencil leads - and as diamond. The only difference between
the two is the arrangement of the carbon atoms. When scientists
arrange the same carbon atoms into a "chicken wire" pattern
and roll them up into miniscule tubes only 10 atoms across, the
resulting "nanotubes" acquire some rather extraordinary
- Have 100 times the tensile strength
of steel, but only 1/6th the weight.
- Are 40 times stronger than graphite fibers.
- Can conduct electricity better than copper.
- Can be either conductors or semiconductors (like
computer chips), depending on the arrangement of atoms.
- And are excellent
conductors of heat.
Prof. Vincent H. Crespi Department of Physics Pennsylvania
Much of current nanotechnology
research worldwide focuses on these nanotubes. Scientists have proposed
using them for a wide range of applications:
1/ In the high-strength,
low-weight cable needed for a space elevator.
2/ As molecular wires
for nano-scale electronics; embedded in microprocessors to help
siphon off heat.
3/ And as tiny rods
and gears in nano-scale machines, just to name a few.
Nanotubes figure prominently
in research being done at the NASA Ames Center for Nanotechnology
(CNT). The center was established in 1997 and now employs about
50 full-time researchers.
"We try to focus
on technologies that could yield useable products within a few years
to a decade," says CNT director Meyya Meyyappan. "For
example, we're looking at how nano-materials could be used for advanced
life support, DNA sequencers, ultra-powerful computers, and tiny
sensors for chemicals or even sensors for cancer."
A chemical sensor they
developed using nanotubes is scheduled to fly a demonstration mission
into space aboard a Navy rocket next year. This tiny sensor can
detect as little as a few parts per billion of specific chemicals
- like toxic gases - making it useful for both space exploration
and homeland defense. CNT has also developed a way to use nanotubes
to cool the microprocessors in personal computers, a major challenge
as CPUs get more and more powerful. This cooling technology has
been licensed to a Santa Clara, California, start-up called Nanoconduction,
and Intel has even expressed interest, Meyyappan says.
Credit - NASA Ames Center for Nanotechnology.
DNA strand between metal atom contacts could function
as a molecular electronics device.
If these near-term
uses of nanotechnology seem impressive, the long-term possibilities
are truly mind-boggling.
The NASA Institute
for Advanced Concepts (NIAC), an independent, NASA-funded organization
located in Atlanta, Georgia, was created to promote forward-looking
research on radical space technologies that will take 10 to 40 years
to come to fruition.
For example, one recent
NIAC grant funded a feasibility study of nanoscale manufacturing
- in other words, using vast numbers of microscopic molecular machines
to produce any desired object by assembling it atom by atom!
That NIAC grant was
awarded to Chris Phoenix of the Center for Responsible Nanotechnology.
In his 112 page report,
Phoenix explains that such a "nanofactory" could produce,
say, spacecraft parts with atomic precision, meaning that every
atom within the object is placed exactly where it belongs. The resulting
part would be extremely strong, and its shape could be within a
single atom's width of the ideal design. Ultra-smooth surfaces would
need no polishing or lubrication, and would suffer virtually no
"wear and tear" over time. Such high precision and reliability
of spacecraft parts are paramount when the lives of astronauts are
Although Phoenix sketched
out some design ideas for a desktop nanofactory in his report, he
acknowledges that - short of a big-budget "Nanhatten Project,"
as he calls it - a working nanofactory is at least a decade away,
and possibly much longer.
Taking a cue from biology,
Constantinos Mavroidis, director of the Computational Bionanorobotics
Laboratory at Northeastern University in Boston, is exploring an
alternative approach to nanotechnology:
Rather than starting
from scratch, the concepts in Mavroidis's NIAC-funded study employ
pre-existing, functional molecular "machines" that can
be found in all living cells: DNA molecules, proteins, enzymes,
envisioned by Constantinos Mavroidis and colleagues resembles
a living cell.
Shaped by evolution
over millions of years, these biological molecules are already very
adept at manipulating matter at the molecular scale - which is why
a plant can combine air, water, and dirt and produce a juicy red
strawberry, and a person's body can convert last night's potato
dinner into today's new red blood cells. The rearranging of atoms
that makes these feats possible is performed by hundreds of specialized
enzymes and proteins, and DNA stores the code for making them.
Making use of these
"pre-made" molecular machines - or using them as starting
points for new designs - is a popular approach to nanotechnology
the wheel?" Mavroidis says. "Nature has given us all this
great, highly refined nanotechnology inside of living things, so
why not use it - and try to learn something from it?"
The specific uses of
bio-nanotech that Mavroidis proposes in his study are very futuristic.
One idea involves draping a kind of "spider's web" of
hair-thin tubes packed with bio-nanotech sensors across dozens of
miles of terrain, as a way to map the environment of some alien
planet in great detail. Another concept he proposes is a "second
skin" for astronauts to wear under their spacesuits that would
use bio-nanotech to sense and respond to radiation penetrating the
suit, and to quickly seal over any cuts or punctures.
Possible? Maybe. Mavroidis admits that such technologies are probably
decades away, and that technology so far in the future will probably
be very different from what we imagine now. Still, he says he believes
it's important to start thinking now about what nanotechnology might
make possible many years down the road.
Considering that life itself is, in a
sense, the ultimate example of nanotechnology, the possibilities
are exciting indeed.
web of nanosensors maps the terrain of an alien planet.
The cross-section at the top-right shows biologically derived
molecules (yellow and red) that would perform the sensing
and signaling functions.