Naturally they are err-ing on the safe side. The restrictions placed on exposure are no where near the fatality rate. Light radiation sickness begins at about 50â"100 rad (0.5â"1 gray (Gy), 0.5â"1 Sv, 50â"100 rem, 50,000â"100,000 mrem). High fatality rates occur at ~400 rems.* The EPA sets a 25 to 75 rad restriction on workers involved in emergencies (such as these). They do not want to go past light radiation sickness. The plants did spike to a rather high amount on the initial day (~700 mrem). However, that has come down extremely quickly. This morning it was measured at 75mrems just outside the front gate. Used fuel storage typically emits 2mrems per hour. While the lack of water is a concern, it is not nearly as bad as the claims make. The average dose on workers has been high enough to push them into the EPA restrictions, the public dose has been significantly smaller. While it is cause for concern, it really isn't that bad. http://www.nei.org/resourcesandstats/documentlibrary/newplants/factsheet/faq---japanese-nuclear-energy-situation/ * http://www.ornl.gov/sci/env_rpt/aser95/tb-a-2.pdf

Learn how to drive. On a more serious note, the actual formula is 4d{+2}/k-d{+2}. He's done a bunch of theoretical math. Kudos to him http://articles.sfgate.com/2011-03-05/news/28661918_1_graphing-calculator-international-math-olympiad-stanford-university-math

The batteries didn't die. There are two cooling systems in the reactor. One cycles through the actual reactor core. This is cooled by a secondary system that powers the actual turbines that generate the power. The backup generators have the power to cycle both systems. The batteries do not have nearly enough power to cycle both systems. The batteries in the plant were cycling the primary system on the reactor core; however, that coolant was just getting hotter and hotter since they had lost the backups on the secondary system. They then did as they are trained, they opted to flush the secondary system with another source and vented some of the heat out of the primary system (the source of the radiation). They set it up and flushed it with seawater. Sadly, there had been some hydrogen buildup in the secondary system due to a number of other issues that had happened; that caused the plant to explode. The reactor core was not breached and while they were leaking a fairly descent amount of radiation, they got that under control extremely quickly. The actual exposure was roughly the same as a few flights from CA to Europe. While it was indeed tragic, they did exactly what they needed to in order to stop it from becoming a real crisis. The company responsible for the plants has posted a number of statements about the plants that I'd recommend reading. http://www.tepco.co.jp/en/index-e.html

While the summary tends to allude to such future possibilities, this robot is a long ways away. It is a "human-robot project." Meaning that a human is required to perform the tasks, and that they are not automated. The Canadian Space Agency provides information on the robot. http://www.space.gc.ca/asc/eng/missions/sts-123/dextre.asp

Doing operations with these robotics requires a communication link, which would first have to be built by automated robotics (which this is not) or humans; I for one believe we will visit mars personally by the time we have automated robotics that could perform the necessary tasks to create this type of comm-link.