Scientist produces most accurate and detailed topography maps of the solar system
Washington, August 20 : A scientist has produced the most accurate and detailed
topography maps of the solar system as yet.
The scientist in question is Robert Gaskell from the Planetary Science Institute in the
US.
According to his NASA Exceptional Achievement medal, his maps of the asteroid Itokawa
are "the highest resolution description of an asteroid."
For developing the maps, Gaskell uses a method called stereo-photo-clinometry, or SPC.
Just as stereophonic means sound from different directions, stereo-photo means light from
different directions, and clinometry means that slopes, or inclines, are being
measured.
"SPC means finding slopes from the way the surface looks under different illuminations,
and once we know the slopes we can find the heights," said Gaskell.
Gaskell has created sophisticated software that combines hundreds of spacecraft images
of varying resolution to produce the maps.
His newest project, which was recently funded by NASA, will create highly accurate maps
of the entire surface of Mercury based on images sent back by NASA's Messenger
spacecraft.
Messenger flew by Mercury in January and is scheduled to go into orbit in 2011, after
several passes of Earth, Venus and Mercury.
Currently, Gaskell is combining images from that flyby with those taken by Mariner 10,
which visited Mercury in 1973, to produce initial maps.
Gaskell's maps not only give scientists useful information about a body's surface, they
also can be used for navigating spacecraft, calibrating spacecraft instruments, and
gaining information about the geology, internal structure and past history of an
object.
In addition to Mercury, Gaskell is mapping eight of Saturn's moons, including
Enceladus, a frigid world punctuated by icy geysers.
In October, NASA may use those maps as navigational tools to plot - and possibly adjust
- the Cassini spacecraft's trajectory as it flies past Enceladus.
Lidar data from the NEAR spacecraft, which went into orbit around the asteroid Eros in
2000, is being compared to Gaskell's maps of its surface, and an error of about 14 meters
has been detected.
"We suspect that these residuals (errors) are primarily due to incorrect spacecraft
position," Gaskell said. "In other words, the orbits are not exactly correct. We intend to
solve for those orbits and then the new orbital data can be used to more accurately
determine the body's gravitational field," he added.
Once Gaskell's computers produce maps covering an entire body, they yield a very
accurate image of the object's shape.
--ANI
