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Steven York
It is possible that, for the first flight, using at least some film will still be a good idea, despite the mass and complexity penalties.
Something like I-Max or Omni-max (or at the very least, Vista-vision, which uses 35mm film running sideways, with double the frame area of conventional 35mm) is probably in order. But film is going to be very heavy, technically complex, and comes with a double storage whammy, it must be protected in terms of radiation and temperature. And remember that, with film, accumulated exposure counts just as much as peak dosages. This wasn't much of a problem with a mission time of a week or two, but it's a major consideration for longer stays. Plus the delta-V has to be there to take the film stock there AND back. It would be interesting to see the specs on the I-max camera that was taken up on the Shuttle.
It is easy to grealy underestimate the weight and complexity of the equipment and film if you haven't worked with them. A super-8 film cartridge weighs probably five or six ounces, and will fit in your hand. But it contains only about 3 minutes worth of film. A VHS cassette offers the potential of better image quality. It is probably three or four times as large, and five or six times as heavy, but it will replace at least twenty of those cartridges. It could replace as many as 120 in mathematical terms. In practical terms it's a LOT more. You see, a lot of film gets wasted because you change the magazine every time the film gets low. You have "ends," just like end-rolls of paper in printing. There's a lot of wastage there, especially if you're worried about not having enough film in the camera when something exciting or historic happens. But, the flip side of that is that you tend to be very conservative in what you film, and thus it's certain that you'll miss many interesting or important moments. You can't rewind a film magazine and reuse it if you shoot ten minutes of boring and useless shots in hope of getting ten really great seconds.
To look at this another way, imagine the print of a feature length 35mm film. It's a laminated disk of celluloid 35mm thick, about five feet across, with about a 12" hole in the middle. I don't know what the weight is, but probably over 100 pounds. That's about two hours of finished film. But to actually produce that film took a lot more film stock. A super low-budget cheapie might use three times as much. A feature probably ten times as much. I've heard of documentaries with ratios of 100-1. Though this last isn't typical, it may be more representative of what we're doing.
Now, I-Max has ten times the image area, and the film itself weighs about seven or eight times as much (figuring the area lost to sprocket holes and the like). Because the film is much heavier, and moving much faster, all the cameras and supporting equipment are far heavier. Lenses are much larger, and less light sensitive.
Even off-the-shelf HDTV technology is getting pretty good, and it's possible we can do better. Images used for entertainment, rather than scientific, purposes, can use compression to reduce the necessary bandwidth, and we can cut it to a fraction just by screening the footage on the moon, and only sending over the good bits. Also, an unattended sytem could continue to beam compressed pictures after the crew has left.
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