Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!usc!zaphod.mps.ohio-state.edu!rpi!dali.cs.montana.edu!milton!hitchner@riacs.edu From: hitchner@riacs.edu (Lewis Hitchner) Newsgroups: sci.virtual-worlds Subject: Re: Virtual Mars Message-ID: <14576@milton.u.washington.edu> Date: 16 Jan 91 19:37:30 GMT References: <14441@milton.u.washington.edu> Sender: hlab@milton.u.washington.edu Organization: Research Institute for Advanced Computer Science Lines: 76 Approved: cyberoid@milton.u.washington.edu As several respondents have noted, NASA has already begun implementation of a "Virtual Mars" system. Mike McGreevy has publicized the concept of virtual planetary exploration for several years in both spoken (e.g., keynote speech at ACM's CHI '89) and published form. We also have an on-going project (on-going in spite of recent federal budget cutbacks in NASA's Mars-Lunar Initiative program) entitled "Visualization for Planetary Exploration" that already implements many of the concepts proposed by Shawn Carlson in his article. However, our project is merely a prototype and the "reality" is somewhat limited due to the limited resolution data currently available (digital elevation data derived from Viking orbiter satelite imagery) and due to the limitations of current display technology and graphics hardware technology. But, even given these limitations, we have been successful (at least, in our opinions) in demonstrating that virtual planetary exploration is feasible -- in a limited way today, and in a much more realistic way in the not too distant future. The system we are developing is intended for use by research scientists, such as the NASA, USGS, and university planetary geologists who are funded by NASA to study geological features of the planets (and, I might add, who have been doing so for a number of years using both remotely gathered satellite data as well as first hand data collection at terrestial study sites similar to Martian terrain -- Death Valley, and Antartica). Some initial presentations of our system to some of these people have indicated that they feel such systems will be very useful in their research (however, they also strongly support the need for human presence for examining micro-features). A few extra comments: - Carlson and one of the follow-up'ers referred to data resolution and the quantities needed, storage problems, etc. Our data is quite low resolution -- 1 km grid spacing, measured in meters 16 bits per elevation value. That's pretty crude when you want to see things smaller than continents. BUT -- we have that data for the whole planet. So, it amounts to nearly 1/2 GigaByte (we also have another 9/10 GByte of higher resolution digital imagery or texture map data for about 35% of the planet). By the way, this data is in the public domain and is available from NASA Goddard's NSSDC (Natl. Space Sciences Data Center). What we are working with now is orders of magnitude less data than what will be available real soon. Venus is now being imaged by Magellan's SAR radar imager which is moderately high res. (I don't know figures, but I believe it is somewhat comparable to USGS DEM data which is 150 meter grid spacing, i.e., roughly 36 times the res. of our Viking Mars data). In 1992 or later (depending on funding) NASA will launch the Mars Observer satellite. MO has a laser altimeter that can directly measure surface topography. It will be capable at its highest resolution of measuring surface elevations to 1.5 meter resolution at similar spatial sampling as that of Magellan I believe (maybe higher). - regarding who might use such systems Though I agree strongly with Carlson's feelings regarding virtual versus real exploration, I'd take exception to his suggestions about how they would be used and by whom. True, there is a great deal of educational and entertainment potential for virtual exploration systems. However, our "prototype" system with its limited performance requires about 1/4 million dollars of computer equipment and highly trained technicians to operate it. Hopefully, some day system development and operation cost will be much, much lower. But, for the near future I can forsee such systems primarily used by highly trained experts in planetary geology. We can't really afford to devote use of such systems to non-specialists who spend "a week" being trained to use the system (by comparison Shuttle astronauts spend 1 to 2 years training for each mission, AFTER their years of general astronaut training, AFTER their years of aviation or science training and education). Initially, at least, I think virtual exploration systems would be most productive when used by experts. For now, I think it would be possible to provide useful educational or entertainment systems without the data accuracy requirements of a scientist . Current commercial systems can satisfy this audience by presenting good lookin g, although physically inaccurate, scenes at a much better cost/benefit ratio than technically precise systems such as ours. Of course, as technology marche s on, we all hope and expect that such systems will become available to a much less restricted audience -- school children, citizens, thrill seeking "virtual explorers" -- for everyone to use.