If ever people stay on Mars at least three years, they certainly have to survive the fall of a large meteorite hit and capacity of a megaton of TNT.
One obvious way to assess the chances of a future encounter with a meteorite impact - to look at the past. However, this task is not so simple, because the density and size of craters, survived for a long time, depending on many factors.
This speed and size, and the trajectory of the meteorite - and geological processes on the celestial body: erosion, tectonic shifts and new attacks over the old. All this is very confusing picture.
Despite this, the lack of attempts to do this work is not observed. So did a group of scientists and working in Puerto Rico Professor William Brukmana (William Bruckman). True, they approached the problem from the other side have prepared a model that should describe the frequency of collision of the Earth with meteorites - and tested its investigation on existing materials.
The authors conclude that the impact force, comparable to the Tunguska meteorite (about 10 megatons of TNT) Earth should experience a once in a century, and the weaker (megaton) - every 15 years. According to scientists, these numbers are perfectly consistent with both the known number of craters, and with the findings of other researchers.
Inspired by this non-random coincidence Brukman and colleagues used the same model of bombardment on Mars - to local conditions, in particular, the lack of atmosphere and the proximity of the main belt. It turned out that the Red Planet has to be restless than us: megaton-scale disaster happen here, apparently, about once every three years.
For future projects, long-term study of Mars, let alone its development, this figure looks quite formidable. They all get a good chance to be in the zone of destructive effects. Rarefied atmosphere can not significantly reduce the energy of the meteorite, so that, other things being equal, Mars will have a much more severe blow than the Earth.
But how about the fact that all sorts of devices explore the Red Planet is not the first year, in the amount of - almost a few decades? After all, no one precise evidence or at least a clear hint of such an event, none of them did not give! To answer this question the author does not count. After all, the future colonists of Mars awaits such a mass of difficulties and dangers, that some kind of megaton explosion unlikely to scare.