The most spectacular (and expensive) use of telepresence in exploration is undoubtedly NASA's program of space probes.Mankind has projected its fragile biological self to places and environments impossible to visit in person.We now know what it would be like to wander the red desert of Mars, plunge into the toxic atmosphere of Titan, and look back at the tiny blue dot of Earth from the orbit of Jupiter.Our powerful, orbiting Hubble virtual eye can see objects so far away that they appear as they did when the universe was born.

The human race has developed very sophisticated "endpoints," or remote robot agents.These endpoints can have capabilities far beyond those of a human observer.The Mars Orbiter, for example, carries nine sensors including: (1) a high resolution visible light imager; (2) an imaging spectrometer, which makes images at 560 different wavelengths, that can be used to measure the composition of the surface; and (3) a radar imager that can map subsurface objects up to a kilometers deep with a resolution of 10-20 meters vertical and 100-300 meters along-trackThese devices produce information far superior to what a human astronaut, peeking out a window or even walking on the surface of Mars, could hope for.

A pair of solar observatories, STEREO 1 and STEREO 2, are now moving into place in orbit around the sun at a distance of 93 million miles. They are in the same orbit as the Earth, with one leading and the other trailing.This setup will allow us to see a stereo image of the sun (actually a movie) with a frame rate of about 250 frames per day.At the optimal 60-degree angle between the two satellites and the sun, we will have a view of the sun from eyes that are 93 million miles apart.This godlike view will allow scientists to use their own built-in human stereoscopic vision systems to gain new quantitative and qualitative understanding of the phenomenon of Coronal Mass Ejections (CMEs).(Earthlings are very interested in CMEs--also called Solar Flares--because they can disrupt our lives by destroying or disabling communication satellites, causing blackouts, and killing astronauts in Earth orbit, for example).

Coronal Mass Ejection (CME) as seen from the Solar and Heliospheric Observatory (SOHO) in June of 2000. Photo reprinted courtesy of NASA.

The extension of the concept of telepresence to robotic exploration involves making the coupling of the teleoperator to the endpoint so natural that the teleoperator feels that s/he is actually at the remote location.If the endpoint is equipped with super-human sensors, it will be necessary to present a compatible virtual environment to the teleoperator that integrates these inputs from the sensors so that s/he can work effectively and naturally, even in such a supernatural environment.In the case of the STEREO project, the sensation of telepresence will be quite intense just because of the stereo viewing.However, a great deal of additional information will be available, such as velocity, radio burst intensity, temperature, or imaging in x-ray and ultraviolet.This data can be combined with the stereo imaging, possibly with false color or sound to yield a virtual environment of great power.

Of course, the main problem with very remote interactive telepresence will always be latency (at least until the speed of light can be increased).Whenever teleoperators need to directly control the endpoint, the delay between command, response, and feedback of the result of the command can be prohibitively long. In the case of the Mars rovers, there is a round-trip delay of about 26 minutes.NASA gets around this in two ways:first of all, Spirit and Opportunity have the capability to carry out many simple commands without further interaction from Earth; and second, a complex series of commands can be uploaded to the Rover which will then run the program without further intervention.Another suggested approach to the latency problem is to run a real-time simulation of the endpoint in operation.This gives instant feedback to the teleoperator.The command stream is sent to the remote system which executes the motion commands, but with a delay.If the endpoint detects that the simulated result has diverged from the actual result, i.e., the rover has not wound up in the location predicted by the simulation, it stops acting and phones home with the bad news.This stops the simulation so it can be reset.

"Victoria Crater" on Mars as photographed by Mars Rover Opportunity, October 16, 2006. Photo reprinted courtesy of NASAExploring nearby but dangerous locales

Virtual exploration is now being used for less exalted purposes as well.Remotely-piloted aircraft seek and destroy enemies, and remotely-operated vehicles storm into buildings too dangerous for human soldiers or police.Police departments in the Baltimore, Maryland, area use a softball-sized device called "Eye Ball R1."When police are faced with a situation where they must enter a possibly dangerous locale, they can throw the Eye Ball in through a window.The robot rights itself, then transmits images and sounds.It can rotate 360 degrees to see what's what before risking lives.

Perhaps the day will come soon when other perilous occupations like fire-fighting or coal mining can be performed via telepresence.It is primarily a matter of improvement in endpoint technology, a much simpler proposition than the development of self-guiding robots now being used in manufacturing.

Exploring data

We can also think of the value of telepresence in the exploration of landscapes of data, rather than geophysical ones. Scientists now are producing datasets of enormous volume as a result of research into genetics, bioinformatics, and the detailed simulation of complex phenomena such as nuclear explosions or weather systems.Interpretation of these huge datasets can be enhanced by interactive exploration of the data pictured as virtual environments.This has been called "Tele-Immersion" by some writers.Humans are able to detect patterns and causal relationships that escape the most sensitive mathematics.Since many data sets are of more than three or four dimensions, some ingenuity is required to represent the data in a comprehensible space.One approach has been to partition the data out to multiple users, each responsible for a subset of dimensions.The technology of "Massively Multiuser Online Games" could be a model for merging the high-quality audio and video of Virtual Presence with the ability to jointly examine and evaluate data.In these games, activity in a virtual world such as Second Life persists whether or not a player is online.One can imagine a virtual laboratory where researchers can come and go, but the results of the collaborative result persists, and work continues whether or not an individual scientist is present.

Scientists at universities and national labs have established very high speed optical "supernetworks" such as the National LightRail or the Global Lambda Information Facility (GLIF).These networks provide institutions all over the planet with private point-to-point multi-gigabit channels (lambdas) which can connect to other lambdas at extremely high bandwidths. Much like the original ARPAnet, these networks are intended to be testbeds to support new applications in scientific collaboration that can take advantage of the availability of a network with enormous bandwidth.To get a feeling for the power of this kind of bandwidth, consider that it would be possible to transfer an entire DVD in about 10 seconds.

The Scripps Oceanographic Institute, for example, has developed software to visualize strain and stress in the San Andreas Fault.In a demonstration in 2005, 100 Megapixel tiled displays were used to visualize, in 3D, the course of movements of the strain field over time, using data stored in Chicago, San Diego, and the Netherlands. Researchers in Rhode Island and three locales in Illinois collaborated on developing a 3D visualization of a hydrodynamic simulation of the entire human arterial system.Microscope endpoints equipped with high definition cameras permit remote scientists to zoom in on brain tissue and superimpose digital data such as electron microscope imagery.While these applications show great promise, the progress in supernetworks so far has been primarily in development of the infrastructure to easily share visualizations and integrate high-quality conferencing.

Topographic images generated
from high resolution radar data
from the Shuttle Radar Topography
Mission in 2000. Photos reprinted
courtesy of NASA.


Exploring the very tiny

Nanotechnology, currently the subject of much research as well as hype, may eventually produce a new realm of telepresence at the opposite end of the cosmic scale from the space probes.However, the fantasy of submicroscopic machines wandering through layers of the earth transmitting back images of seams of coal or pools of oil is probably unlikely.Engineers posit that the power of a machine is proportional to its volume, while the friction it encounters in operation is proportional to its surface area.Therefore, scaling a machine down reduces its power much faster than its friction.Tiny mechanical moving robots are therefore impossible.However, much more subtle techniques are becoming available from the world of biology and chemistry rather than physics and engineering. Molecular-sized probes such as Green Fluorescent Protein are already being used to spy on biological processes in living cells and report back optically.

What's next?

Humans are a compulsively curious species.We must always know what's over the next hill.Soon we will be able to find out what's over that hill without actually going there.Some would say that this is a loss, that getting there is half the fun and we won't really know unless human feet have been there.On the other hand, getting over the hill lets us get a look at the next hill, which might be even more interesting.Why waste time on the dull hills? Stay tuned for further developments.

Selected bibliograpy

California Institute for Telecommunications and Information Technologies Web site, http://www.calit2.net/

Electronic Visualization Laboratory Website, http://www.evl.uic.edu/cavern/.

Ian Grimstead, David Walker and Nick Avis, Collaborative Visualization: A Review and Taxonomy.Proceedings of the 2005 Ninth IEEE International Symposium on Distributed Simulation and Real-Time Applications (DS-RT'05) IEEE Computer Society. 2005.

NASA's Visible Earth Web site, http://visibleearth.nasa.gov.

Special section on iGrid2005: Future Generation Computer Systems.The International Journal of Grid Computing, Volume 22:8 pp. 849-1054; 2006.

The Sun and Heliosphere in Three Dimensions: Report of the NASA Science Definition Team for the STEREO Mission. Johns Hopkins Applied Physics Laboratory, Laurel MD, December 1, 1997.