Space exploration has been one of the man's greatest achievements this century. In 1969, thrill of excitement ran round the globe as Neil Armstrong took the first "small step" on the Moon. This "small step", however, has become a big step for man's exploration in space. Since then, man has been putting a lot of effort on this fascinating industry.
However, space exploration is no easy task when it comes to the economic aspect or the safety of the astronauts. Hundreds of billions of dollars have been spent on the research and construction ( including the design stages ) of various space vehicles and equipment. On the other hand, as we know very little about the Universe, astronauts taking the missions are constantly at risk of unpredictable circumstances such as the space shuttle being struck by a meteor, or even a failure of a component of an equipment.
The space agencies have already taken these problems into account and they came up with a new, safer and more reliable approach for space exploration : the use of Virtual Reality.
Virtual Reality[12], or Virtual Environment Systems are, in general, systems where a user is interactively interfaced to a computer and engaged in a three-dimensional ( 3D ) visual task. The computer provides a virtual domain for supporting the 3D models or complete environment and, given suitable transducers, the user can interact with the system in real time.
With a Virtual Reality interfacing helmet, an astronaut can see a 3D scenario of a planet under exploration and have a sense of being there. This virtual reality technique is known as Telepresence and can be used to familiarise the astronauts with the condition of a particular planet. Alternately, through a different 3D display, a man will be able to view the virtual 3D image of a space shuttle, which he can study ( e.g. to check for possible faults ) before it is being built.
With a specially designed glove worn by an operator, he will be able to control a robotic arm located at a distant place. This kind of virtual reality technique is known as Telerobotic and can be applied to simple tasks such as controlling a telerobotic arm on the Moon to pick up some rock samples through an operator on Earth.
Data Glove is a kind of virtual reality input
device that allows a user to react to the virtual
environment. The data glove shown in the diagram on the right is the
Dextrous Hand Master produced by Exos.
By wearing this data glove on the hand, the robotic arm coupled to this
data glove will replicate exactly the way this data glove is manipulated by
the user. The arm can be directed to, say, pick up an object. Once the object
is in hand, information is sent back to the data glove to apply stress to
the user movement, inducing a sense of holding the object.
This kind of technology is being studied in the
National Aeronautical
and Space Administration ( NASA ) which is the American program to
explore the outer space. In NASA, a two-armed telerobot now
undergoing development can manipulate objects with dexterity approaching that
of a human. The human operator wears a harness with
exoskeleton-like sleeves and glove; the remote manipulation
follows the operators arm, hand and finger movements and feeds back position
and force information so that the operator has a sense of manipulating the
object held by the telerobot. The right diagram shows the Exoskeleton
project under NASA[7].
How does the Data Glove work ?[7]The glove has numerous sensors attached to the back of the hand, for each finger and the thumb. This setup allows the system to find the exact position and orientation of the hand at any instant. Besides, the sensors are also used to measure the joint angles of each finger and the thumb. When combined with recognition software, this data can be used for gesture-based input to the system, these are like short-cut action to a predefined function, such as activating a disc cutter mounted on the robotic arm using hand-gesture rather than pressing the buttons on the keyboard for the same purpose. |
HMD is a device that cuts off visual and audio sensations from
the surrounding world and replaces them with computer generated
three-dimensional images[13].
Imagine you are in the dining room at home. Once you put on a HMD connected to a computer ( the right diagram ), you may feel that you have been teleported to the surface of Mars, with the two moons, the Phobos and Deimos, and numerous stars glowing in the distant horizon. What is in front of you is no longer the dining table but the foot of the gigantic Olympus Mons: a volcano larger than any mountain on Earth . When you take a step forward, your point of view ( 3D ) moves forward in this virtual space. You find yourself no longer in the dining room, you are in the cyberspace of Mars you came across in science fiction. Everything is so real that you cannot deny you are exploring on that planet.
These are all due to the 3D computer generated images ( CGI ) produced by the sophisticated computer. Besides, the head-tracking system senses the exact position and orientation of your head, while the computer uses this set of data to update the view on the display.
A Head-Mounted Display
The housing holds the LCD screens in a fixed position relative to each other to reduce the possibility of image misalignment, and at a sufficient spacing from the operatior's eyes to alloy spectacles to be worn. The focusing ring moves the aspheric lens closer or further realtive to the LCD, to facilitate focusing of the image and to adjust for accommodation variances between different users. The aspheric lens is composed of two convex surfaces each having an aspheric shape. This focuses the image from the 13.5mm x 10mm active matrix LCD screen located approximately 75mm in front of the viewer's eyes, onto the fundus of the viewer's eye with minimal distortions. The perceived field of view is approximately 35° horizontal, and 25° vertical. |
Using the above ideas, a user wearing the data glove and the HMD can actually
be immersed and interact in the cyberspace. This is just like
the VIEW project developed at
NASA Ames. It is
a general-purpose, multi-sensory, personal simulator and
telepresence device. The configuration included head and
hand tracking, wide field-of-view stereo head-mounted displays, speech
recognition, 3D audio output and a tracked and instrumented
glove as shown on the right diagram.
With this setup and different 3D graphical database, we can go
anywhere in the world, or even other planets, making VIEW
a powerful tool for the astronauts training program.
With the HMD and data glove, an astronaut under the training program is able to walk along the planet surface such as the Moon in the virtual world. He can also pick up, say, a rock sample on the virtual planet and perform other various exercises. This can, for sure, give him a better preparation before really going to the planet. As a result, the use of virtual reality technology can train the astronauts more effectively.
However, even if an astronaut is qualified to explore space, bulky spacesuits they wear greatly restrict their arm movement. Besides, in weightless conditions, their working tools float about and drift away from them, making the task even more tedious. NASA has therefore developed a new type of telepresence control devices known as telerobotics. They are designed to aid the astronauts in tasks such as the assembling of a satellite module outside the space shuttle in space or to do some other tasks on the planet.
A data glove allows an astronaut to control a robotic arm to pick
up some rock and soil samples on a planet. This is very useful because
very often, the collection of the samples are radioactive,
hence direct contact by human is dangerous and undesirable.
This kind of technique can also be applied to the maintenance of equipment in the space. Instead of inspecting and repairing the damaged part of, say, an shuttle orbiter by an astronaut directly, a Platform robotic ( right ) can do it for him. An astronaut in the crew cabin can dock the platform robot near the damaged area, and use the data gloves to control the robotic arms onboard to carry out the task. Two cameras on the Platform robotic give a sense of distance to the operator. ( This is an important feature for a good telepresence control since human see things stereoscopically; the two views from each eye merge into one picture in the brain and thus provide the sense of distance. )
Using telerobotic technique, a operator controlling a robot over a distance has a sense of being at the working site and the feeling of manipulating the object held by the telerobot. However, it must be noted that if the operator and the robotic arm are separated by great distances (i.e. interplanetary scale), then short delays must be considered.
On the other hand, in order to ensure that the astronauts can control the telerobot effectively during the mission, they have to undergo special training programs of using the telerobots. During the training program, it is very important to ensure full immersion of the trainees in the virtual environment. Therefore, the controls of the real telerobot must be mimicked. Besides, the system needs to be as real to the actual telerobot as possible. This implies quite a high cost in the development. However, this will still be more cost-effective than using the real thing ( because an untrained operator may damage the real and expensive telerobot ). Besides, accidents involving the use of telerobot during operation will be greatly reduced [6]. One of the examples is the Telepresence Training for Space Shuttle Remote Robotic Manipulator under NASA [8].
Although the use of telerobotic arm can help the astronauts to perform some difficult task, sometimes, an exploration of a planet may be too dangerous for an astronaut to explore directly ( e.g. due to the extreme temperature on the planet ). As a result, a replacement for the astronauts, known as Planetary Explorers are sent to take the harsh mission.
Planetary explorers ( as shown in the left diagram ) replace the
job of the astronauts in these conditions.
These explorers, in the form of robotic vehicles ( often called
rovers ) may be deployed on Mars to find potential landing
sites for future exhibitions and areas of scientific interest. They place
small instruments and gather soil and rock samples for analysis and
possible return to Earth. [9]
However, engineers face problems when it comes to the controlling of the robots at distant planets such as Mars from Earth. If they use direct telepresence to control the vehicles, then the problem is the communication delays. When a rover unexpectedly reaches the edge of a cliff, for example, the picture from its T.V. camera - even travelling at the speed of light - takes about ten minutes for the 600 million kilometres journey to reach Earth. The command "stop" from the operator on Earth takes about the same time to return to Mars - and in the interventing 20 minutes the rover has already fallen off the cliff!
Therefore, the designers of the robots must give them more than just eyes, arms
and legs ( or wheels ), they must give them brains. The robots
must have enough Artificial Intelligence ( AI ) to sense simple
dangers and then stop and wait for further instructions [4].
This type of control
is Semi-Autonomous or Semi-Telepresence and
the right diagram shows a Mars rover with laser pathfinder for avioding
obstacles.
Unlike the earth's weather conditions, the temperature range in other planets are extreme. With high temperature in day-time ( when facing the sun ) and very low temperature at night. Under these circumstances, metal expands, contracts and vibrates which could result in damage to the instruments onboard or the chassis of the vehicle. As a result, engineers have tested numerous materials and robots designs which could tolerate such environments [2]. Besides, space travel is very expensive and every gram goes in the book. In order to ensure minimum consumption of energy by the planetary explorers, they must be as light as possible [3]. This research leads to new classes of Ultra-light robotics sampling devices to be created and used.
There are also many ideas on the general design of the robots. On Mars
there are
formidable obstacles such as rocks, soft earth and steep slopes for
the vehicle
to overcome. Some engineers believe the robot should have legs ( like insect )
rather than wheels. Others think the robots should not walk at all
but flow in the air by means of a high-tech balloon, known as
Aerobots.
As a result of the techniques described above, the use of Virtual Reality can benefit Man's exploration of space. However, to ensure a high probability of successful missions, regular safety inspection of space equipement such as the space shuttle is crucial. Again, we can make use of Virtual Reality Techniques to conduct this task.
Regular inspection of the space shuttle is crucial for
safety and determining what and where repairs are
needed. For example, preflight and
post-flight inspections and rewaterproofing of approximately 20,000 thermal
protection tiles on the lower surface of the space shuttle orbiter is needed.
However, this kind of highly human-intensive inspection is both
time consuming and difficult due to the large size
and numerous components to be inspected. Besides, some areas are either
too dangerous to access ( due to chemical exposure ) or
difficult to access such as the internal engine and fuel tank
inspection [9]. As a result, the task is beginning to be
done by small telerobots
( sometimes known as Nano-robots )
which do these inspections for humans in a
quick and efficient way.
A telerobot is placed in the area under inspection such as the internal of an engine ( it cannot be accessed by man!) to check for cracks or fractures. The operator outside uses the computer system such as the data glove and the HMD to control the telerobot to inspect the area. The diagram above shows a telerobot called "Tesselator" developed by NASA Space Telerobotics Program for space shuttle inspection.
Apart from Tesselator, the NASA has also done a research on Remote Surface Inspection for effective inspection of the space mission equipment.
Finally, in order to take the mission in a safe and efficient way, a good design of space equipment such as the space shuttle is very important. Virtual Reality technique, again, does provide a lot of help!
Imagine what will happen to NASA when all the time and money spent on the
research, design and development of their space shuttle,
it was found that the shuttle is incapable of re-entering
the world's atmosphere because the wings were carelessly designed? It will
surely be a disrepute to NASA as well as the time and money wasted.
However, with the use of virtual
reality technique, the designer can use the HMD to view the
virtual prototype model ( as well as each of its internal
part ) and to use computer simulation for examining imperfections before
development. For example, two machine parts can be checked for
correct fit in all dimensions before actually being made [11].
Besides, simulation can be used to see the thermodynamics of the space shuttle when it is subjected to various degrees of pressure during the re-entry into the Earth's atmosphere. The diagram above shows the simulation results on the surface pressure of the space shuttle which is a project ( High-Fidelity Space Shuttle Simulation [10]) conducted by the Space Systems Division of NASA.
So far, we have illustrated the uses of virtual reality in different areas of space exploration and how they aid us in numerous ways. It can be justified to conclude that it is truly a technology we cannot do without in this fascinating industry.
As mentioned earlier, landing on the Moon has been one of the giant steps for man's quest of space exploration. It gave people strong belief that it is also possible to travel to distant planets. But going there is about an adventure and a new era of scientific knowledge - entering new worlds to discover new chemical elements, to gain clues about the mystery of the Universe and ultimately, the hope to encounter Extra-Terrestrial Intelligent (aliens)!
As manned space travel is dangerous, smart robots with artificial brains have already been developed and tested on the Moon, and even smarter ones will be landing on Mars scheduled for 1997. However, for real understanding of the new planets a robot simply cannot achieve our needs. The reason is, no matter how smart a robot may be, it cannot match the most versatile and miniaturised of computers, the human brain. The first geologist on the Moon was able to interpret the story of the lunar landscape on the spot. Such tasks are impossible even for the smartest robot, their intelligence are only designed to do specific tasks.
Therefore the method for future space exploration is the use of Telepresence. As this technology improves, the perceived senses of the human operator on Earth will be as good as if he was really there on the distant planet. The robots can do the simple tasks such as avoiding obstacles or gathering mass data and information while we interpret those information and decide on its next move.
Soon, as faster spacecraft immerges, we can send telerobots deep into outer
space beyond our solar system in search for extra-terrestrial
intelligent, exchanging scientific knowledge such as genetic
manipulation, energy generating methods or other
non-scientific knowledge such as cultural activities that
could revolutionise the way we live.
Besides, there are also many promising commercial and educational advantages. Commercial space laboratories can be sent into orbit for scientific research in weightless conditions. Scientists, who may not have the physical ability to qualify as an astronaut, may carry out their experiments on Earth through the use of telepresence control. Current interest in this area are bacteria growth and material manufacturing in weightless environment.
As space travel becomes more accessible, the space agencies can deliver telepresence controlled robots to other planets. For example, children can have the chance to experience being on the Moon through the control of the robot located there. Consequently drawing more attention on the next generation in the hope that they will join us in this long journey of space exploration.
Usefulness : 8 / 10
Readability : 7 / 10
Comment : A lot of examples of telerobotics related to
space exploration, as well as on NON-NASA
applications such as aircraft inspection and
biological aspect.
Usefulness : 7 / 10
Readability : 6 / 10
Comment : Very detailed discussion on various projects done
by the Rover and Telerobotics Technology
Program under NASA e.g. Aerobots.
Author : Michael E.Jebb
Usefulness : 6 / 10
Readability : 7 / 10
Comment : A readable article on telerobotics in
space exploration.
Year : 1995
Usefulness : 6 / 10
Readability : 6 / 10
Comment : Concentrate on the technical aspect of
telerobot on planetary exploration.
Author : M.A.Gigante Year : 1993 Usefulness : 6 / 10 Readability : 6 / 10 Comment : Good description on data glove and HMD
Author : Michael E.Jebb
Usefulness : 5 / 10
Readability : 6 / 10
Comment : Discussion on general
training and simulators in telerobotics.
Usefulness : 5 / 10
Readability : 5 / 10
Comment : A brief discussion of Exoskeleton - an
example of a data glove.
Usefulness : 4 / 10 Readability : 5 / 10 Comment : An overview of the training program
Usefulness : 4 / 10 Readability : 5 / 10
Author : Daniel F.Dominik
Usefulness : 4 / 10
Readability : 4 / 10
Comment : A technical discussion on the
simulation of the Space Shuttle.
Author : Francis Hamit
Publisher : SAMS Publishing
Year : 1993
Usefulness : 4 / 10
Readability : 4 / 10
Comment : A technical discussion on
Engineering, Design and Architecture
using virtual reality technique.
Author : John Vince
Year : 1993
Usefulness : 3 / 10
Readability : 7 / 10
Comment : A paper on Flight Simulation
but good definition on the term Virtual
Reality.
Author : Michael Heim Publisher : Oxford University Press Year : 1993 Usefulness : 3 / 10 Readability : 5 / 10
Author : Jerry Isdale
Year : 1993
Usefulness : 7 / 10
Readability : 7 / 10
Comment : Explain the different modes
of Interface assosciated to virtual
reality, including Telepresence as
a form of virtual reality.
Author : Bernie Roehl
Year : 1995
Usefulness : 7 / 10
Readability : 6 / 10
Comment : Some brief discussions on DIS,
behaviour levels in Distributed
Virtual Reality system
Author : Francis Hamit
Year : 1993
Publisher : SAMS Publishing
Usefulness : 5 / 10
Readability : 5 / 10
Comment : Some ideas describing virtual
reality as a form of "acting".
Author : John Vince
Year : 1993
Publisher : Academic Press Ltd.
Usefulness : 8 / 10
Readability : 8 / 10
Comment : A very good and comprehensive discussion
on flight simulation using VR technique.
Author : Bill Gates
Year : 1995
Publisher : Penguin Group
Usefulness : 7 / 10
Readability : 7 / 10
Comment : Very interesting description on flight
simulation.
Usefulness : 6 / 10
Readability : 6 / 10
Comment : Discussion on general simulation
environment with some technical terms.
Author : Jeffrey Maddalon
Year : 1993 - 1996
Usefulness : 4 / 10
Readability : 5 / 10
Comment : Describe important events and
improvements to the real-time flight
simulation facility located at NASA's
Langley Research Center.
Author : Jim Bauman
Year : 1995
Usefulness : 7 / 10
Readability : 6 / 10
Comment : Many good examples of military
applications using VR.
Author : Francis Hamit
Year : 1993
Publisher : SAMS Publishing
Usefulness : 7 / 10
Readability : 6 / 10
Comment : Very informative account on the U.S military
SIMNET.
Author : Roger Smith
Year : 1995
Usefulness : 6 / 10
Readability : 6 / 10
Comment : A very comprehensive article, many
technical issues and some areas on
military applications, especially
on simulation.
Author : Kristy Ann Pike
Year : 1995
Usefulness : 3 / 10
Readability : 5 / 10
Comment : Concentrate on the marketing of VR
products to military application over
the year. Only little area on the
actual applications.
Author : Michael E. Jebb
Year : July 29, 1995
Usefulness : 9 / 10
Readability : 9 / 10
Comment : It gives a very good idea of
telerobotics in medicine together with the
advantages, problem encountered as well as
other related links.
Author : Greg Heacock (1)
John Marshall, Ph.D.(1),
Prof. Franz Fankhauser, M.D.(2).
Toni C. Emerson, MSLIS (3)
(1) University of London, UMDS, St. Thomas's, U.K.
(2) University of Bern, Switzerland
(3) HIT Lab, University of Washington
Year : 1994
Usefulness : 7 / 10
Readability : 8 / 10
Comment : It gives a comprehensive idea of the Head
Mounted Display ( HMD )
Author : Advanced Technology Program, NIST
Year : October, 1995
Usefulness : 7 / 10
Readability : 7 / 10
Comment : It surveys in great detail the
applications of virtual environments and
related technologies for health care.
Author : Francis Hamit
Year : 1993
Publisher : SAMS Publishing
Usefulness : 4 / 10
Readability : 7 / 10
Comment : It talks about general
telepresence but not concentrate on any
medical aspect. So it only gives some
idea of general telepresence.
Author : Robert J. Stone
Year : 1994
Publisher : Academic Press Limited
Usefulness : 4 / 10
Readability : 6 / 10
Comment : Only general telepresence is
discussed, with some projects of
telerobots such as the UK VERDEX
project.
Usefulness : 8 / 10
Readability : 7 / 10
Comment : A lot of examples of telerobotics related to
space exploration, as well as on NON-NASA
applications such as aircraft inspection and
biological aspect.
Usefulness : 7 / 10
Readability : 6 / 10
Comment : Very detailed discussion on various projects done
by the Rover and Telerobotics Technology
Program under NASA e.g. Aerobots.
Author : Michael E.Jebb
Usefulness : 6 / 10
Readability : 7 / 10
Comment : A readable article on telerobotics in
space exploration.
Year : 1995
Usefulness : 6 / 10
Readability : 6 / 10
Comment : Concentrate on the technical aspect of
telerobot on planetary exploration.
Author : M.G.Gigante Year : 1993 Usefulness : 6 / 10 Readability : 6 / 10 Comment : Good description on data glove and HMD
Author : Michael E.Jebb
Usefulness : 5 / 10
Readability : 6 / 10
Comment : Discussion on general
training and simulators in telerobotics.
Usefulness : 5 / 10
Readability : 5 / 10
Comment : A brief discussion of Exoskeleton - an
example of a data glove.
Usefulness : 4 / 10 Readability : 5 / 10 Comment : An overview of the training program
Usefulness : 4 / 10 Readability : 5 / 10
Author : Daniel F.Dominik
Usefulness : 4 / 10
Readability : 4 / 10
Comment : A technical discussion on the
simulation of the Space Shuttle.
Author : Francis Hamit
Publisher : SAMS Publishing
Year : 1993
Usefulness : 4 / 10
Readability : 4 / 10
Comment : A technical discussion on
Engineering, Design and Architecture
using virtual reality technique.
Author : John Vince
Year : 1993
Usefulness : 3 / 10
Readability : 7 / 10
Comment : It is a paper on Flight Simulation
but good definition on the term Virtual
Reality.
Author : Michael Heim Publisher : Oxford University Press Year : 1993 Usefulness : 3 / 10 Readability : 5 / 10