ABSTRACT
There is another point, which is worth mentioning, though it refers to a date far in the future. ~o doubt there will evemually be manned missions to the Jovian system, but we will never be able to get too close; any astronaut venturing inside the main radiation zones will meet with a hasty and unpleasant death. But Callisto is more than 1,000,000 miles (1 ,600,000 km) from the Giant Planet, and is therefore, presumably, less hazardous than the rest, so that it may welJ be the site of the first landing. When this will happen we do not know, but certainly it will be a fascinating project.
