Solar Wind (Slight Return)

Circling back to my note on solar wind and the Martian atmosphere.

In the note, I described how the solar wind interacts with the ionosphere of Mars to create an induced magnetosphere. Recent data from ESA’s Mars Express mission suggests that this induced magnetosphere actually protects the Martian atmosphere from the ion loss expected to be caused by that same solar wind. Thus, the long held idea that the solar wind blew away Mars’ atmosphere is now in question.

The article below outlines an alternative hypothesis. Rather than losing atmosphere to the solar wind, maybe Mars can’t hold onto one because its gravity is just too weak.

Starman Update

“According to the revised data, Rivkin says, it will take the Tesla about 18.8 months to complete one trip around the sun. This means that the car will reach its farthest distance from Earth in about half that time. The Tesla will cross the orbit of Mars twice per orbit, so Musk is still fulfilling his wish to send his Tesla “to” Mars—it’ll just take a little longer between visits.”

Hohmann Orbits and Sports Cars

I want to make this clear: SpaceX is not putting a Tesla into orbit around Mars. Not only would that be illegal by international treaty, but it would be technically impossible with the technology SpaceX currently possesses. What SpaceX is doing is putting a Tesla into a Hohmann Transfer Orbit between Earth and Mars that is very similar to the one we will likely use to get humans to that planet. Continue reading “Hohmann Orbits and Sports Cars”