## Even MIT students can make misteaks.

30 Jun 2013, 21:58 UTCFinding Delta V between various places in the solar system has been one of my hobbies. I like to learn as well as share what I know about this topic. So I occasionally Google search strings that include the term "Delta V".Googling: Delta V Mars. The first hit is a Wikipedia article, the second hit is How Much Delta V do you need to get to Mars - Yahoo! Answers.A fellow who calls himself ronwizfr confidently asserts that the delta V from earth orbit to Mars transfer is 6.6 km/s. Ronwizfr cites an MIT student project for a class called Solving Complex Problems.The MIT page cited is a well done presentation until the students get to constants:Then the students made an arithmetic error. The distance from the earth to the sun is 1.49X1011 meters, not 1.49X1010 meters. Their radius for Mars' orbit is also off by a factor of 10.The MIT students correctly plug in these wrong quantities to get speeds that are off by sqrt(10):The velocity of the earth is not 94,384 m/s but closer to 29,846 m/s. Likewise velocity of Mars isn't 74,467 m/s but closer to 23,548 m/s. Their quantities would have been correct if the earth ...