Virtual Reality in Space Exploration

by Geoffrey WONG and Vincent WONG


Contents


1. Introduction

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.


2. Gearing Up the Virtual Interface

As described earlier, virtual reality technology is so powerful that it gives the user a sense of being immersed in the virtual world. This kind of immersion is a very important feature of effective virtual reality systems as it is central to the paradigm where the user becomes part of the simulated world, rather than the simulated world being a feature of the users own world[12]. In order to let the users / operators have the sense of being immersed in the virtual environment, two important devices are needed :

2.1 Data Glove[5]

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.


2.2 Head-Mounted Display ( HMD )

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 right diagram shows a simple HMD ( no audio tracking system ) that allows the user immersed in the virtual environment. It consists of six major components :

the housing
head strap
liquid crystal display ( LCD ) screens
aspheric lenses
focusing rings
video cable

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.


As a result, using these high tech but user friendly data glove and HMD, an astronaut can experience being on a planet millions of miles away to control a robotic arm to do various tasks. Without these two important devices, he may only be able to use the keyboard and mouse as input devices and view the non-3D display on the monitor, making a 3D task difficult.

2.3 The VIEW ( Virtual Interactive Environment Workstation ) project[5]

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.





3. An Experience in Space

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.


4. Telerobotics - The Third Arm of the Astronaut [1]

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.


5. Planetary Explorer - The New Astronaut

Manned missions for planetary exploration are often very dangerous or even impossible due to a number of reasons [4]. In some cases, such as for the surface of Venus, the level of radiation are unacceptable to the human body, while in others, such as for the outer solar system, round-trip missions with current propulsion technology would last almost a human lifetime! Besides, weightless environment in space have a great impact on the astronauts' health condition: Russian "cosmonauts" who spent a year weightless in a space station found that their muscles wasted away, their bones became brittle and their immune system began to malfunction. Also, in interplanetary space, astronaut faces the hazard of cosmic ray particles ( harmful radiation ) that may damage their cells and DNA. Furthermore, even if he reaches the destination alive, again he faces more danger such as inhabitable environment ( extreme temperature or volcanic region ) or encountering unfriendly aliens which could jeopardize the $20 billion-per-head 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.

Robot Technology

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.


6. The Space Shuttle Inspector

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!


7. The Space Shuttle Design Assistant

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.


8. Closing Thoughts ......

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.


References

[1]
NASA Space Telerobotics Program (http://ranier.oact.hq.nasa.gov/telerobotics_page/telerobotics.html)
   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.

[2]
Planetary Robotics (http://lmooradian.jpl.nasa.gov/Planetrobs.html#Nanorovers)
   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.

[3]
Telerobotics in Space (http://www.mcs.anl.gov/home/jebb/telerobot/space.html)
   Author  : Michael E.Jebb
   Usefulness  : 6 / 10  
   Readability : 7 / 10  
   Comment  : A readable article on telerobotics in
            space exploration.

[4]
Planetary Exploration : Navigation methods and a generation of robots (http://www-dse.doc.ic.ac.uk/~nd/surprise_95/journal/vol2/pma/article2.html)
   Year    : 1995
   Usefulness  : 6 / 10
   Readability : 6  / 10
   Comment  : Concentrate on the technical aspect of
            telerobot on planetary exploration.

[5]
Virtual Reality System pg 3 - 25
   Author  : M.A.Gigante              
   Year    : 1993         
   Usefulness  : 6 / 10
   Readability : 6 / 10 
   Comment  : Good description on data glove and HMD

[6]
Training and Simulators in Telerobotics (http://www.mcs.anl.gov/home/jebb/telerobot/train.html)
   Author  : Michael E.Jebb
   Usefulness  : 5 / 10  
   Readability : 6 / 10
   Comment  : Discussion on general
            training and simulators in telerobotics.

[7]
Exoskeleton Task (http://robotics.jpl.nasa.gov/../tasks/exo/homepage.html)
   Usefulness  : 5 / 10  
   Readability : 5 / 10
   Comment  : A brief discussion of Exoskeleton - an
            example of a data glove.

[8]
Telepresence Training for Space Shuttle Remote Robotic Manipulator (http://tommy.jsc.nasa.gov/~li/MDF.html)
   Usefulness  : 4 / 10                               
   Readability : 5 / 10
   Comment  : An overview of the training program

[9]
Remote Surface Inspection Task (http://robotics.jpl.nasa.gov/tasks/rsi/homepage.html)
   Usefulness  : 4 / 10
   Readability : 5 / 10

[10]
High-Fidelity Space Shuttle Simulation (http://www.nas.nasa.gov/NAS/TechSums/9293/9.html)
   Author  : Daniel F.Dominik
   Usefulness  : 4 / 10  
   Readability : 4 / 10  
   Comment  : A technical discussion on the
            simulation of the Space Shuttle.

[11]
Virtual Reality and the Exploration of Cyberspace pg 235 - 242
   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.

[12]
Virtuality Reality Techniques in Flight Simulation
   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.

[13]
The Metaphysics of Virtual Reality
   Author  : Michael Heim
   Publisher : Oxford University Press
   Year    : 1993
   Usefulness  : 3 / 10  
   Readability : 5 / 10


10. Appendix

Sources Related to Virtual Reality :

1. Sources Related to the Philosophy of Virtual Reality :

[1]
What is Virtual Reality? (http://www.cms.dmu.ac.uk/~cph/VR/whatisvr.html)
   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.

[2]
Distributed Virtual Reality - Overview (http://sunee.uwaterloo.ca/~broehl/distrib.html)
   Author : Bernie Roehl
   Year : 1995
   Usefulness  : 7 / 10
   Readability : 6 / 10
   Comment  : Some brief discussions on DIS,
            behaviour levels in Distributed
            Virtual Reality system

[3]
Virtual Reality and the Exploration of the Cyberspace pg 322 - 337
   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".

2. Sources Related to Virtual Reality on Flight Simulation :

[1]
Virtual Reality Techniques in Flight Simulation
   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.

[2]
The Road Ahead pg 129 - 130
   Author  : Bill Gates
   Year : 1995
   Publisher : Penguin Group             
   Usefulness  : 7 / 10
   Readability : 7 / 10
   Comment  : Very interesting description on flight
            simulation.

[3]
Modelling and Simulation (http://www.sc.ist.ucf.edu/~OTT/1_3/index.htm)
   Usefulness  : 6 / 10
   Readability : 6 / 10
   Comment  : Discussion on general simulation
            environment with some technical terms.

[4]
Flight Simulation News (http://bigben.larc.nasa.gov/fltsim/simnews.html)
   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.

3. Sources Related to Virtual Reality on the Military Aspect :

[1]
Military Application of Virtual Reality (http://www.cs.umd.edu/projects/eve/eve-articles/II.G.Military.html)
   Author  : Jim Bauman
   Year : 1995
   Usefulness  : 7 / 10  
   Readability : 6 / 10  
   Comment  : Many good examples of military
            applications using VR.

[2]
Virtual reality and the Exploration of Cyberspace pg 223 - 233
   Author  :  Francis Hamit              
   Year    : 1993   
   Publisher : SAMS Publishing      
   Usefulness  : 7 / 10
   Readability : 6 / 10 
   Comment  : Very informative account on the U.S military
            SIMNET.

[3]
The Application of VR Technology to Existing Battlefield Simulation (http://www.mystech.com/~smithr/papers/vr_world.html)
   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.

[4]
Commercial Virtual Reality Applications (http://www.ist.ucf.edu/~ADPA/ndmag/feb96/vr.htm)
   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.

4. Sources Related to Virtual Reality on Medical Telepresence :

[1]
Telerobotics in Medicine (http://www.mcs.anl.gov/home/jebb/telerobot/medical.html)
   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.

[2]
Viewing Ocular Tissues with A Stereoscopic Endoscope
Coupled to a Head Mounted Display (HMD)
(http://www.hitl.washington.edu/publications/heacock/)

   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 )
[3]
Virtual Environments for Heath Care (http://www.nist.gov/itl/div878/ovrt/projects/health/vr-envir.htm)
   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. 

[4]
Virtual Reality and the Exploration of Cyberspace pg 254 - 256
   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.

[5]
Virtual Reality Systems pg 181 - 202
   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.

5. Sources Related to Virtual Reality in Space Exploration :

[1]
NASA Space Telerobotics Program (http://ranier.oact.hq.nasa.gov/telerobotics_page/telerobotics.html)
   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.

[2]
Planetary Robotics (http://lmooradian.jpl.nasa.gov/Planetrobs.html#Nanorovers)
   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.

[3]
Telerobotics in Space (http://www.mcs.anl.gov/home/jebb/telerobot/space.html)
   Author  : Michael E.Jebb
   Usefulness  : 6 / 10  
   Readability : 7 / 10  
   Comment  : A readable article on telerobotics in
            space exploration.

[4]
Planetary Exploration : Navigation methods and a generation of robots (http://www-dse.doc.ic.ac.uk/~nd/surprise_95/journal/vol2/pma/article2.html)
   Year    : 1995
   Usefulness  : 6 / 10
   Readability : 6  / 10
   Comment  : Concentrate on the technical aspect of
            telerobot on planetary exploration.

[5]
Virtual Reality System pg 3 - 25
   Author  : M.G.Gigante              
   Year  : 1993          
   Usefulness  : 6 / 10
   Readability : 6 / 10 
   Comment  : Good description on data glove and HMD

[6]
Training and Simulators in Telerobotics (http://www.mcs.anl.gov/home/jebb/telerobot/train.html)
   Author  : Michael E.Jebb
   Usefulness  : 5 / 10  
   Readability : 6 / 10
   Comment  : Discussion on general
            training and simulators in telerobotics.

[7]
Exoskeleton Task (http://robotics.jpl.nasa.gov/../tasks/exo/homepage.html)
   Usefulness  : 5 / 10  
   Readability : 5 / 10
   Comment  : A brief discussion of Exoskeleton - an
            example of a data glove.

[8]
Telepresence Training for Space Shuttle Remote Robotic Manipulator (http://tommy.jsc.nasa.gov/~li/MDF.html)
   Usefulness  : 4 / 10                               
   Readability : 5 / 10
   Comment  : An overview of the training program

[9]
Remote Surface Inspection Task (http://robotics.jpl.nasa.gov/tasks/rsi/homepage.html)
   Usefulness  : 4 / 10
   Readability : 5 / 10

[10]
High-Fidelity Space Shuttle Simulation (http://www.nas.nasa.gov/NAS/TechSums/9293/9.html)
   Author  : Daniel F.Dominik
   Usefulness  : 4 / 10  
   Readability : 4 / 10  
   Comment  : A technical discussion on the
            simulation of the Space Shuttle.

[11]
Virtual Reality and the Exploration of Cyberspace pg 235 - 242
   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.

[12]
Virtuality Reality Techniques in Flight Simulation
   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.

[13]
The Metaphysics of Virtual Reality
   Author  : Michael Heim
   Publisher : Oxford University Press
   Year    : 1993
   Usefulness  : 3 / 10  
   Readability : 5 / 10

6. Other Sources Related to Virtual Reality :

[1]
On The Net: Internet Resources in Virtual Reality (http://www.hitl.washington.edu/projects/knowledge_base/onthenet.html)
[2]
VR Bibliography (http://www.cms.dmu.ac.uk/~cph/VRbib.html)
[3]
Distributed Virtual Reality : applications for education, entertainment and industry (http://www.nta.no/telektronikk/4.93.dir/Loeffler_C_E.html)
[4]
The Dive Home Page (http://sics.se/dce/dive/dive.html)
[5]
The Encyclopedia of Virtual Environments (http://www.cs.umd.edu/projects/eve/eve-main.html)
[6]
Virtual Environment Vehicle Interface (http://maas-neotek.arc.nasa.gov/~piguet/VEVI/)
[7]
Virtual Reality Home Page (http://logic.csc.cuhk.edu.hk/~s951230/index.html)
[8]
The Cardiff VR Pages (http://www.cm.cf.ac.uk/User/Andrew.Wilson/VR/index.html)
[9]
The Virtual Reality Experience (http://www.carleton.ca/~jweston/27523/papers/bromberg)
[10]
Virtual Reality (http://www.euro.net/sala/vr.html)
[11]
From Reality to Virtuality: New Tools for Distributed Learning (http://www.iat.unc.edu/events/march96.html)
[12]
The Ergonomics in Teleoperation and Control Laboratory (http://vered.rose.toronto.edu/)
[13]
Research on Ubiquitous Telepresence (http://www.cs.colorado.edu/~zorn/ut/Home.html)
[14]
OntarioTelepresence Project's home page (http://www.dgp.utoronto.ca/tp/tphp.html)
[15]
Virtual Reality and Telepresence (http://www.cs.umd.edu/projects/eve/vrtp.html)
[16]
Telepresence Remotely Operated Vehicle (TROV) (http://maas-neotek.arc.nasa.gov/TROV/trov.html)
[17]
A Virtual Environment for Automotive Design (http://infolane.com/infolane/stereog/gmvr.html)
[18]
Simulation Based Design & Virtual Reality (http://www.luorc.edu/sbd-gcrmtc/sbd.html)
[19]
MARS Virtual Reality Simulator (http://www.dciem.dnd.ca/DCIEM/HF/G-07.html)
[20]
Hubble Space Telescope Repair Training System (http://www.jsc.nasa.gov/cssb/vr/Hubble/hubble.html)
[21]
Virtual Environments for Training (http://www.isi.edu/isd/VET/vet.html)
[22]
Virtual Reality: A Practical Tool for Training (http://www.rti.org/research/vr_training.html)
[23]
Sharing Visualization Experiences among Remote Virtual Environments (http://www.mcs.anl.gov/FUTURES_LAB/CAVE/PAPERS/WALES/share.html)
[24]
A gloveless interface for interaction in scientific visualization virtual environments (http://www.ssd.sterling.com/Papers/SPIE_95_VI/)
[25]
Immersed in Technology - Art and Virtual Environments (http://www-mitpress.mit.edu:80/mitp/recent-books/art/mosih.html)
[26]
UNC-CH Telepresence Research Group (http://www.cs.unc.edu/~mcmillan/telep.html)
[27]
Medical Virtual Reality (http://medvr.res.ncc.go.jp/)
[28]
Distributed Virtual Reality -- An Overview (http://sunee.uwaterloo.ca/~broehl/distrib.html)
[29]
Distributed VR Systems (http://www-dse.doc.ic.ac.uk:80/~np2/virtual_reality/distributed.html)
[30]
Battle Tech (http://www.virtualworld.com/BattleTech/BattleTech.html)