This item represents an excellent advance in the thinking around a
practical space elevator. We have woken up to the reality that while
rigging one to get us into Earth Orbit may simply simply exceed the
bounds of physics, it is a perfectly great idea for smaller object
like the moon and any comparable.
It may turn out to be the viable solution for Mars and by extension,
a number of moons of Saturn and Jupiter. It is possible to envisage
an expeditionary ship assembled in Earth Orbit and then sent to
establish the elevator. Combined with an orbiting base station, a
free flow of goods can be established to the surface. So even if an
Earth elevator is unlikely, the natural efficiency of the system and
its immunity to external factors will make this an excellent solution
as we expand our penetration of near space in the solar system.
All this presupposes superior lift technology that gets the tonnage
up there and is not dependent on the advent of the MFEV or Magnetic
Field Exclusion Vessel which may simply make all this very obsolete
once deployed.
LiftPort plans to
build space elevator on the Moon by 2020
By David Szondy
Artist's impression of
the lunar elevator's lunar base and climber car (Image: LiftPort)
When the late Neil
Armstrong and the crew of Apollo 11 went to the Moon, they did
so sitting atop a rocket the size of a skyscraper that blasted out
jets of smoke and flame as it hurtled skyward. For over half a
century, that is how all astronauts have gone into space. It’s all
very dramatic, but it’s also expensive. Wouldn’t it be cheaper
and easier to take the elevator? That’s the question that Michael
Laine, CEO of LiftPort in Seattle, Washington, hopes to answer with
the development of a transportation system that swaps space-rockets
for space-ribbons.
Rockets have done
sterling service in launching satellites and astronauts into orbit.
The trouble is, they’re inefficient and therefore expensive.
Putting a payload into orbit means that the rocket must not only lift
the payload, it has to carry the payload, the fuel to lift it and the
rocket, the fuel to lift the fuel, the rocket and the payload, the
fuel to lift all that and so on. The space elevator is
based on the idea of cutting out the middleman and just lifting the
payload. It does this by way of a tower of mind-boggling height –
from sea level at the equator, clear up to geosynchronous orbit
35,800 kilometers (22,238 mi) up with an elevator for going up and
down it like it was the Seattle Space Needle.
The idea even predates
liquid-fueled rockets. It was first proposed by Russian space pioneer
Konstantin Tsiolkovsky in 1895. Inspired by the Eiffel Tower, he had
the idea of building what came to be known as the “Tsiolkovsky
Tower.” He saw the advantage of a tower tall enough that launching
satellites would be a matter of simply releasing them like pigeons,
but The tower wasn’t remotely practical because no conceivable
self-standing structure could be built so high and not collapse under
its own weight.
For decades, the idea
languished and was largely forgotten, until is was reinvented in 1959
by another Russian scientist, Yuri N. Artsutanov. His new design
remained unnoticed as well because his paper was not published in
English until many years later, so the space elevator was reinvented
twice again by American scientists in 1966 and 1979. The cycle might
have continued if Sir Arthur C. Clarke hadn’t made the construction
of a space elevator the plot of his 1979 novel Fountains of
Paradise. Sir Arthur was very keen on the idea and liked to predict
that the elevator would be built “ten years after everyone stopped
laughing.”
By the 1970s, the
basic design of a possible future space elevator had been refined.
Tsiolkovsky’s tower was replaced by a ribbon suspended from a space
station in geosynchronous orbit over the equator. Those two points
are important because at that distance and at the equator, the
station remains over the same spot on the Earth at all times. Above
the station at a distance of 144,000 kilometers (90,000 miles –
nearly the halfway point to the Moon) is a gigantic counterweight
that holds up the ribbon and the station by centrifugal force, which
the Earth’s gravity counters and balances.
This system doesn’t
envision the use of an actual elevator. A 35,800 kilometer-long cable
isn’t exactly practical and the counterweight needed for the thing
would be the size of a small mountain. Instead, it uses a
self-propelled car that climbs the ribbon. How the car is powered
varies from electricity carried by the ribbon to lasers beamed from
the ground and the station. The car itself would be a high-tech
affair and is often imagined as a climbing robot or something equally
exotic.
The space elevator is
simple in concept, but nearly impossible in execution. The main
problem is that no material known to science is strong enough to make
the ribbon. Steel and titanium are much too weak. In fact, the ribbon
needs to be 60 to 200 times the strength of steel if it isn’t going
to snap under its own weight. Quartz fibers and even diamonds have
been considered and recently carbon nanotubes seem
promising, but engineers are still a long way from answering that
basic question of what the heck to make it out of.
Other problems include
the cold in the upper atmosphere, which plays havoc with lubricants,
materials and electronics – not to mention the danger of ice
building up on the ribbon. Then there’s inclement weather buffeting
it. Above the atmosphere, satellites and space debris whizzing by
pose their own challenges.
LiftPort – heading
for the Moon
LiftPort ultimately
wants to build a space elevator on Earth, but the company isn't
planning on doing it in one go. Instead, Laine and his team are
settling for a more modest goal – building an elevator on the Moon
by 2020. This is much easier. For one thing, there’s no air on the
Moon, so no icing problems. Also, the lower gravity means that no
unobtanium is needed for the ribbon. Kevlar is strong enough for the
job. And finally, there’s very little in the way of satellites or
debris to contend with.
LiftPort’s goal in
its Kickstarter funding campaign is a modest US$8,000, which it has
already surpassed. This may seem like chicken feed for such an
ambitious program, but Laine intended it as a way of sparking public
interest. The ultimate goal is to raise $100,000 to $3 million with
the first round of funding to be used to continue a preliminary study
of the system.
"The study will
include characterization of materials; analysis of required rocketry
and robotics; and evaluation of landing sites and methods of
anchoring to the Lunar surface," says Laine. "Addiionally,
Ribbon spooling, infrastructure deployment, and micrometeorite
mitigation techniques will be explored."
If all goes well,
Laine believes construction of the lunar elevator could begin by
2020. The LiftPort lunar elevator would be deployed from lunar orbit
with a spacecraft lowering a lander on the ribbon. On contact with
the surface, the lander will anchor itself. After that, landing on
the Moon will be as simple as docking with the craft in lunar orbit,
transferring to the climber car and reading a book on the way down.
The immediate goal,
however, will be to test the system on an elevator only two
kilometers (1.24 mi) high, which would be suspended from balloons.
LiftPort plans to build a robot climber capable of scaling the
ribbon. In order to test this, the team will construct a sort of
“vertical treadmill” for the robot to climb before taking on the
real thing.
Further money raised
will be used to develop better sensors, increase the height of the
suspended ribbon to 5 km (3.1 m), develop a new robot and then go on
to climbs of 30 km (18.6 m) and, finally, a full feasibility test of
the system, which Laine hopes to carry out next year.
Laine sees a number of
applications for such space elevators beyond launching spacecraft and
giving tourists a restaurant with one fantastic view. He sees the
elevator as being the tallest line-of-sight radio tower possible,
which would be a tremendous boon to communications. Also, even the
technology for suspending the ribbon from balloons opens the
potential for quickly deployable emergency
communications/surveillance towers.
But part of the
attraction for Laine is simply adrenaline-raising fun. Anyone for the
ultimate bungee jump?
The video below
depicts how a lunar elevator would be deployed.
Sources: LiftPort ( Kickstarter
page) via Cosmic Log
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