Robots in Space

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14 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Robots in Space

Source: ROBOTS IN SPACE, NASA FACTS, NF
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Robots have intrigued humans and captured our imaginations for centuries. As early as the 8th
century B.C., Homer, in his epic poem Illiad, described "handmaids of god

resembling living young
damsels." Science fiction literature and motion pictures also have pictured mobile devices, human
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like in form, encased in metal, and able to do those everyday tasks from which many of us would
like to be freed.

Despite our long fa
scination with robots, the first U.S. patent for an industrial robot was issued less
than 40 years ago to George C. Devol.. In 1958, Joseph F. Engelberger, a science
-
fiction enthusiast,
developed the first programmable manipulator, or robot. Since then, ro
bots have become
indispensable to the industry, to medicine, and to the United States space program. And while
today's robots may not look or perform as fantastically as those featured in literature or movies,
they are the fulfillment of dozens of science
fiction visions.

Robots: What and Why

A robot may be define as a self
-
controlled device consisting of electronic, electrical, or mechanical
units. More generally, it is a machine that functions in place of a living agent. Robots are especially
desirable fo
r certain work functions because, unlike humans, they never get tired; they can endure
physical conditions that are uncomfortable or even dangerous; they can operate in airless
conditions; they do not get bored by repetition; and they cannot be distracted
from the task at
hand.

Thus, robots are especially valuable to space exploration. Not only can they travel to environments
too hostile or too distant for human explorers, but they can also enhance the work schedule of a
manned space mission.

Types of Robot
s in Space

Today, two types of devices exist which can be considered space robots. One is the ROV (Remotely
Operated Vehicle) and the other is the RMS (Remote Manipulator System).

Typically, ROVs are used in nuclear facilities for inspection and repair in
areas too dangerous for
humans, and by police bomb squads for removal of potentially hazardous materials. Space
researchers are especially interested in this type of robot for terrain exploration in space.

An ROV can be an unmanned spacecraft that remains
in flight, a lander that makes contact with
an extraterrestrial body and operates from a stationary position, or a rover that can move over
terrain once it has landed. It is difficult to say exactly when early spacecraft evolved from simple
automatons to r
obot explorers or ROVs. Even the earliest and simplest spacecraft operated with
some preprogrammed functions monitored closely from Earth.

The most common type of existing robotic device is the crane
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like RMS (Remote Manipulator
System), or robot arm, most

often used in industry and manufacturing. This mechanical arm
recreates many of the movements of the human arm, having not only side
-
to
-
side and up
-
and
-
down
motion, but also a full 360
-
degree circular motion at the wrist, which humans do not have. Robot
a
rms are of two types. One is computer
-
operated and programmed for a specific function. The
other requires a human to actually control the strength and movement of the arm to perform the
task. To date, a robot arm has performed a number of tasks on several
NASA space missions
-
serving as a grappler, a remote assembly device, and also as a positioning and anchoring device for
astronauts working in space.

Robots and Unmanned Space Exploration

Robotic spacecraft are especially useful in space exploration where d
istances are too long and
environments too hostile and dangerous to send humans. Before astronauts were sent to the Moon,
a series of Surveyor spacecraft soft
-
landed on the lunar surface between 1966 and 1968. Triggered
by electronic signals from Earthboun
d humans, four Surveyors transmitted thousands of images
back to Earth and analyzed solid samples gathered with an extendible claw. Based on this
information, the United States was able to plan its manned Apollo Moon missions.

The Soviet Lunokhod 1 lunar r
over can be called the first mobile robot to explore an
extraterrestrial body. In 1970 it rolled out onto the Moon's surface from the Luna 17 spacecraft
and was remotely controlled by Soviet scientists through television viewers. One of its autonomous
func
tions was the ability to sense when it was going to tip over and automatically stop and wait for
signal from Earth to help it proceed.

Two Viking spacecraft, launched in 1975, parachuted landers to the Martian surface with television
cameras, soil scoops a
nd analyzers, and weather stations. Some of these devices transmitted
valuable information to Earth until 1982. If humans are ever to explore or even inhabit Mars,
additional robotic probes similar to these are essential.

An exciting and practical use for
ROVs is as unmanned deep space probes. The Voyager 2 proves
are excellent examples of how unmanned space missions can greatly increase our understanding of
the universe. They are programmed automatically to make adjustments in operations far from
direct hu
man interaction. The Voyager missions, launched in 1977, have provided scientists with
opportunities to view Jupiter, Saturn, Uranus, and Neptune, and they continue to provide thought
-
provoking new data. They have already traveled over 2.8 billion miles, a
nd if they continue to
operate, the Voyager proves will hurtle on past the edge of the solar system to interstellar space,
sending back signals that are still unfeasible for a manned mission to gather at this point in our
space development.

Robots and Mann
ed Space Exploration

To date, the Space Shuttle's Remote Manipulator System (RMS) is the only robotic device which
has been used on manned space missions. The robot arm made its test debut in space aboard the
Space Shuttle Columbia Mission STS
-
2 in 1981. T
hen in 1983, on Space Shuttle Challenger Mission
STS
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7, when Sally Ride made her historic flight as the first American woman in space, the robot
arm was used to release and recover a pallet satellite.

Space Shuttle Mission STS
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41C, a 1984 Challenger flight
, illustrates some of the advantages of
using remote manipulators in space. One of the mission's goals was to capture the malfunctioning
Solar Maximum Mission Satellite (Solar Max) for repair and re
-
orbit. During an extravehicular
activity (EVA), astronaut

George D. Nelson was unsuccessful in trying to grab the satellite by hand
in an untethered space walk, but later, Nelson and astronaut James van Hoften used the Shuttle's
giant robot arm to grapple the satellite; then they repaired it in the Shuttle's gia
nt robot arm to
grapple the satellite; then they repaired it in the Shuttle's payload bay. Once the repair was
successfully completed, the RMS was used to redeploy the satellite.

On the same Challenger mission, human intervention was required to help the r
obot arm deploy
the largest payload yet handled by a Shuttle. The Long Duration Exposure Facility (LDEF)
weighing 21,300 pounds (9700 kilograms) was so large it blocked the vision of Astronaut Terry
Hart who was manipulating the robot arm. Using a remote T
V monitor for visual feedback, Hart
first used the RMS to latch onto a grapple fixture on the LDEF to activate its power sources, and
then used the RMS to lift, steady, and release the LDEF into orbit. The LDEF contained 57
experiments and was the first sa
tellite specifically designed to be returned to Earth; so, in 1990, the
RMS was again used to grapple the satellite and lower it into the Shuttle's payload bay for the
return trip to Earth.

A second satellite retrieval mission was accomplished in 1984 duri
ng Space Shuttle Discovery
Mission STS
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51A. This time, a manual retrieval and berthing procedure was accomplished by an
astronaut positioned in a restraint system located at the end of the RMS. This foot restraint device,
which functions like a "cherry pic
ker," holds and positions the astronaut operated the robot arm
from inside the Shuttle's cabin.

On Space Shuttle Atlantis Mission STS
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61B, launched in 1985, two important construction
experiments were conducted using the RMS. These experiments, referred to

as EASE and
ACCESS, tested space assembly of two different structures consisting of beams and nodes and
evaluated the roles EVA might play in building the planned Space Station.

All these examples of using the RMS during manned space missions rely on tele
operation,
continuously controlled remote manipulation by a human. (Teleoperation comes from the Greek,
telchir, meaning "distant hands.") Although the RMS has an automated mode, it has never been
used in an actual recovery operation. This mode, however, w
as tested on STS
-
3 in 1982.

Future Robots in Space

NASA's current plans for development of space robots concentrates on three main uses of remote
manipulation in space: servicers, cranes, and rovers. Servicers are humansized, multi
-
arm, remote
manipulators

which are used for servicing and assembly. Cranes, like the RMS currently operated
on Space Shuttle missions, are long single arms used for repositioning larges masses. Rovers are
mobile platforms for transporting payloads on planetary servicers and extra
terrestrial surfaces.

In its research, NASA's approach is to focus on remote manipulation systems which demonstrate
robustness, or the ability to cope with problems; versatility, or the ability to do a variety of tasks;
and simplicity, offering the operato
r a sophisticated system in a package that reduces complexity
-

much in the same way a powerful software package allows a nonexpert to manipulate the
capabilities of a computer. The strategy is to develop remote manipulation technology where
humans and mac
hines have both redundant and complementary roles.

Today's space robots operate either by teleoperation (continuous remote control of a manipulator)
or robotics (preprogrammed control of a manipulator). Both areð? ? :ly controlled by humans. The
distinctio
n is that the teleoperators are controlled by humans remote in distance, and robots are
controlled by humans in time (by way of computer programs). NASA's goal is to develop a system
of telerobotics where teleoperation and robots are combined. The future o
f robots in space is not a
question of human versus machine, but rather a combination of the best capabilities of human and
machine to achieve something which surpasses the capabilities of either alone. Robots using
Artificial Intelligence (AI) along with
computers will eventually be capable of "learning" how to
perform complex tasks.

A number of telerobotic devices are currently under development. The Goddard Space Flight
Center in Maryland is the lead NASA center for developing robots like the Flight Tele
robotic
Servicer which will assemble and service the Space Station. Similar projects are under way at the
Johnson Space Center in Texas and the Kennedy Space Center in Florida in support of crew
activities and ground processing of STS. These devices will f
etch tools and astronauts, perform
hazardous launch duties, and even tend crops in orbiting gardens. Planetary rovers and walkers
also are being designed both with wheels and leg
-
like appendages. They will have the technology to
safely and autonomously tra
nsverse long distances on unfamiliar terrain.

On May 24, 1989, President George Bush spoke on America's space agenda for the 21st century. "I
want to reaffirm my support for the quest to create a spacefaring civilization. That objective is not
just our amb
ition, but our destiny..."NASA's work with robotics is sure to play and important role
in that destiny.