John Batchelor Hotel Mars, Wednesday, 5-21-25

The Space Show

John and I welcomed DR. Robin Andrews from the UK to discuss planetary defense with us. Robin introduced us to the term "City-Killer" which pertains to the size of an asteroid that could potentially hit and damage Earth. This type of asteroid, were it to hit populated area, could do serious damage and injury to the area of impact. The damage would be considered localized rather than global. Robin provided us with a few examples of such asteroid impacts over history, plus the size of such a rock hitting the Earth would be around 140-160 meters across. Our guest talked about the recent NASA DART mission which sent an ipactor to an asteroid to test if it could be moved, possibly out of the way of hitting Earth. The DART mission was successful. Robin pointed to the U.S. as the main researching entity on such dangerous impacts though he did shout out to ESA and a few other organizations. He was asked about the decision making process to possibly absorb an impact in an area or to evacuate the area, a decision nobody wants to make. Robin was asked questions about rubble pile asteroid along with other kinds of rocks, plus he talked about other potential interceptor missions including nuclear and using the idea of a gravity tractor to tow the asteroid out of the way. Robin supported others in this field by saying the warning time to get involved in defending Earth from an incoming rock was critical as we needed to get to the potential dangerous asteroid when it was still fairly far from Earth. In the second part of our program, John asked Robin what he would do with an unlimited budget for planetary defense. Robin spoke to having infrared observations, testing nuclear interceptors and having rockets and missions on standby if needed bo te used. He commented on existing and soon to be existing hardware that would be useful in the search for the "City-Killer." Vera Rubin was one such tool he mentioned. When asked if a nuclear interceptor might trigger an EMP, he said no because the nuclear explosion would be millions of miles from Earth.