(November 15, 2012 at 4:26 pm)Daniel Wrote: Plus, do NASA really know how to land their space probes? 50% of Mars probes have failed to successfully reach their destination... I'd call that a pretty big failure rate, especially when you consider the cost involved in sending probes to mars.
Consider also that the average distance from Earth to Mars is about 225 million kilometres, or 139,808,518 miles and some change. This distance varies between 54.6 and 401 million kilometres respectively, which works out to about 33,926,867 to 249,169,848 miles. That's a huge volume of space. NASA aren't so stupid as to send their probes zooming off any old how, hoping that by chance alone at least one of them will actually get there, so they select their launch windows very carefully such that the distance that has to be covered, plus the projected position and movements of the target planet (it would be the height of bad manners for the planet not to be there when the probe arrives), allows for the most energy-efficient transfer orbits. Given suitably inexpensive and efficient energy generation it may be possible to eschew transfer orbits in favour of direct flight, à la Star Trek, but for now we're stuck with them.
These transfer orbits are necessarily slower than direct travel could ever be, taking around six Earth months as opposed to thirty-nine days according to one projection. So that's six months of being exposed to cosmic rays, dust particles, micrometeroids, Solar winds, etc.
Add to which the spacecraft are designed to be as lightweight and compact as the mission profiles allow, again in the interests of economy in fuel not to mention costs, plus the fact that relativity constrains the telemetry connection between spacecraft and Mission Control, meaning that the probe has to rely on its own artificial intelligence combined with preset landing procedures, plus the fact that the landing sites don't come furnished with runways and landing lights, and that fifty percent success rate, arguable anyway, is starting to look pretty good. You try parking your car, by remote control, with a time delay of several minutes, and we'll measure your success rate.
Orbital mechanics - it's not rocket surgery.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'
