The first images showing surface details as small as 17 miles across, will be taken Tuesday night when Mars is 34.6 million miles from Earth. A full-color photograph of the planet made from those images will be released for the world to see early Wednesday.
"Of course, what people will care most about are the pretty pictures, and they will be spectacular," said Jim Bell of Cornell University, who is leading one of the teams collecting Mars data from the Hubble.
"The pictures we take this week are probably the ones that will be in astronomy textbooks for the next several decades."
A second set of images taken within in an hour of Mars' closest approach on Wednesday, will show the Red Planet 1,400 miles closer.
The photos are stored in an onboard computer before they are transmitted to the Goddard Space Flight Center in Greenbelt, Md., and eventually to the Space Telescope Science Institute in Baltimore, which will release the images.
This week's pictures will be the sharpest views of Mars ever taken from Earth, or in this case, Earth's orbit. There are spacecraft orbiting Mars that are much closer, but the Hubble has capabilities those craft don't have. The space telescope, for example, can capture ultraviolet wavelengths.
Free of the distorting effect of Earth's atmosphere, the Hubble is routinely used to track atmospheric changes and study Mars' geology. Ozone and water vapor in the Martian atmosphere, for example, are among the items that can be traced by examining ultraviolet light on Mars.
When the Earth and Mars were in a similar position in 2001, the two planets were about 43 million miles apart, said Keith Noll, an astronomer at the Space Telescope Science Institute.
While Mars is very well studied, the planet's new proximity 9 million miles closer, combined with other data collected since 2001, might help researchers learn something new, Noll said.
Peter Schultz, a Brown University geology professor who studies Mars but is not involved in the Hubble observations, said the space telescope's pictures, in addition to their scientific value, will help spur public interest.
"Is this few percent closer going to make a big difference? I'm not sure about that, we'll have to wait and see," Schultz said. "On the other hand, there is also the subliminal side, the purely humanist side ... the feeling that I was able to say, 'I saw Mars when it was the closest.' That does something to my soul.
"It's a good thing, you know. It's all part of human nature."
By Alex Dominguez