Fission Rockets - Next Generation in Space
Exploration
Chances are, you own a smart phone or some kind of electronic device
with capabilities that would stun even an Apple engineer from 10 years
ago. We've come to expect that technology advances at a mind-
boggling pace, but just how far has rocket technology advanced in,
say, the past three decades?
Not much.
The rockets that sent men to the moon were powered by chemical
combustion, which in its most powerful form ignites hydrogen with
oxygen. The space shuttle main engine, essentially the state of the art
for rocket propulsion, uses the same chemicals.
No doubt, these rockets do their job well for what we ask of them.
Send astronauts to the International Space Station? No problem. Send
astronauts to the moon? Sure. But, suppose we wanted to dream a
little bit bigger, and actually explore the rest of the solar system and
beyond. How far can these chemical rockets send us?
Not very far.
It turns out, through the quirky laws of Newtonian mechanics, that the
exhaust velocity of a rocket is one of the most important parameters
in determining how far it can send a payload. Chemical rockets have
fundamental energy limits that give them a maximum exhaust velocity
that is too low for most piloted missions with destinations further than
the moon.
Fission rockets could be a vital stepping-stone technology towards the
next generation of interstellar space exploration, researchers say.
The rockets that sent men to the moon were powered by chemical
combustion, which in its most powerful form ignites hydrogen with
oxygen. The space shuttle’s main engine, basically the state of the art
for rocket propulsion, uses the same chemicals.
Although these rockets do their job well but they have fundamental
energy limits, which restrict them to a maximum exhaust velocity that
is too low for most piloted missions with destinations beyond moon.
While interstellar missions may seem like the stuff of science fiction,
but the technology needed to facilitate them currently forms an active
area of research, and novel propulsion systems usually contemplate on
extremely energetic reactions as a means to liberate more energy per
unit mass of propellant.
Common areas of research comprise fission rockets, fusion rockets and
even antimatter rockets.
“The technology roadmap to antimatter, or even fusion rockets could
easily be decades in the making, but there is one technology that we
have available today that represents the critical first step in the long
road to the stars, namely fission,” said Richard Obousy, senior
scientist for Icarus, an international group of volunteer scientists and
engineers dedicated to working out the challenges of interstellar
voyages.
The fission rocket being referred to here is the Nuclear Thermal
Rocket, or NTR. An NTR uses nuclear fission as an energy source
instead of chemical combustion, and uses just hydrogen as a
propellant, allowing it to achieve a very high exhaust velocity and high
thrust, Discovery News reported.
Project Icarus: Reaching for Interstellar Space
Starting this month, Icarus Interstellar Inc., the managing company
for Project Icarus, is collaborating with General Propulsion Sciences, a
small propulsion research company based in Washington D.C., for a
new effort to pursue the development of NTRs and other fission-based
space technologies.
The program, dubbed Project Bifrost, which was initiated by Research
Lead Tabitha Smith (Strategic Officer of General Propulsion Science)
and Brad Appel (Program Manager of Nuclear Propulsion at General
Propulsion Science) identifies fission as a crucial stepping-stone
technology towards the next generation of space travel, and will take
steps to advance the technological maturity of NTRs.
Project Bifrost is an ambitious study examining emerging space
technologies that could lay the foundation for future interstellar flights
and investigates the utility of fission for future space missions.
Project Bifrost was initiated by research lead Tabitha Smith (strategic
officer of General Propulsion Science) and Brad Appel (program
manager of Nuclear Propulsion at General Propulsion Science), working
in collaboration with Icarus Interstellar Inc., a nonprofit foundation
dedicated to achieving interstellar flight by the year 2100.
In the coming decades, sending humans to Mars is believed by many
to be the Holy Grail for space exploration, a mission that NTRs are
ideally suited for.
International cooperation is seen as a vital part of future large-scale
space projects in the space community at large, as it encourages
transparency, expedites completion times and splits costs.
It's worth noting that as with many technologies in space exploration,
the 1960s were the golden age for NTRs. Between 1955 and 1973, the
U.S. government spent $1.4 billion in an NTR program called
Rover/NERVA, anticipating it would be used after Apollo was
completed. Although it was ultimately canceled before a flight could be
achieved, the program was tremendously successful in proving that
NTRs work. The knowledge gained from NERVA remains a vital
resource for future NTR development.
Through the interstellar space
We live in an exciting time in which NASA's Kepler Space Telescope
churns out discoveries of new exoplanets — whole other worlds — on a
daily basis. Just last month, scientists working with Kepler confirmed
that they located a planet orbiting within the 'habitable zone' of its
host star — a special region where an Earth-like planet could maintain
liquid water on its surface.
You may be tempted to ask how long it would take for us to send a
spacecraft over to one of those exoplanets and take a closer look. To
answer that question, consider Voyager 1, one of humanity's fastest
spacecraft, and certainly the farthest space probe from Earth. If we
were to suddenly re-aim Voyager 1 towards one of these new solar
systems, it would take more than 70,000 years to reach even the
closest of stars.
ANI
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