Hydrogen Space
Travel
NASA has used hydrogen for years to launch rockets and fuel space
shuttles. In fact, every time we see a rocket launched on television,
the enormous thrust and cloud of smoke and fire is caused by the
ignition of the liquid hydrogen tanks.
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All
Photos Courtesy of NASA
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NASA has used to power of hydrogen to propel dozens of manned
and unmanned missions into space. The Space Shuttle uses a combination
of liquid hydrogen and liquid oxygen to create a maximum thrust
level of 512,950 pounds, which is equivalent to greater than 12,000,000
horsepower.
As far back as 1903, a Russian schoolteacher, Konstantin Tsiolkovsky
was the first to theorize that not only was space travel a possibility,
but the rockets used for space travel needed to be built in stages
and hydrogen and oxygen would be the most powerful fuels to use.
Talk about science fiction preceding science. Sometimes future
thinkers are just that.
On July 20, 1969 the Apollo 11 Lunar Module, with low fuel light
flashing, set down of the moon's surface for the first time in
history. The Module used liquid hydrogen and nitrogen in the form
of hydrazine (n2h4) as a propellant to both land and take off
from the moon's surface.
Most people know that liquid hydrogen was used for fuel in all
of the space missions to date. What most people do not realize
however, is that even on the Apollo 11 Lunar Module, hydrogen
fuel cells were used to power the electronics inside the spacecraft.
The Proton Exchange Membrane (PEM) fuel cells used liquid hydrogen
and oxygen to create electricity and also provided water as a
byproduct, which served as drinking water for the crew and a coolant
for critical electronic components.
Three 28-volt power units (1.5 kW each), consisting of 31-cells
operating in parallel, supplied electricity to both the command
and service modules. Even if two of the hydrogen fuel cell power
units failed, the third would supply power for a safe return.
In over 10,000 hours of use, over 18 missions none of the fuel
cell units had ever failed.
PEM fuel cells were also used as far back as 1962 - 1966. The
alkaline-based fuel cells were used in Apollo, Apollo-Soyuz and
Sky Lab missions. Today, the space shuttles use three 12 kW fuel
cells, which supply all of the power onboard. The PEM power units
consist of a stack of 96 fuel cells with potassium hydroxide electrolytes.
According to Alex Ignatiev, the director of the NASA-funded TcSAM,
"Our key advance was making the heart of the fuel cell -
the sheet of electrolyte that controls the flow of electrically
charged ions - out of a thin film only one micron thick. The thinness
cuts down internal resistance to electric current, so we can get
comparable power output at much lower operating temperatures."
Before 2020, NASA astronauts will once again walk on the moon.
According to the Vision
for Space Exploration outlined by President Bush in 2004,
setting up a base on the moon and further extending our reach
throughout the solar system will happen over the next 15 years.
The new spaceship will combine the best of Apollo and Space Shuttle
technology and will be able to carry four astronauts at a time
to the moon and stay for as long as six months.
Hydrogen is sure to fit into the electrical generation needs
of this new mission. Some of this new fuel cell technology may
even make its way into the commercial sector as well. We'll just
have to wait and see what the future holds.
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