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”

Gale Crater Panorama

JPL posted a nifty panorama from Curiosity today.

There’s also a video description at https://www.youtube.com/watch?v=U5nrrnAukwI.

(Regarding the color of the sky, note the comment at the end of the video: “To aid geologists, colors in the image are white balanced so rocks appear the same color as the same rocks would on Earth.”)

The Color of the Sky

The color of the sky plays a central role in the first book of the series. This makes it important that I get it right. This it not as easy as one might expect. Obviously, no human eye has seen the Martian sky. We have imagery from our robotic probes on the surface. But what a camera sees is not what a human perceives. The truth is that we do not currently know what the Martian sky will look like to a person standing on the surface. We can, however, make an educated guess. Continue reading “The Color of the Sky”