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Tracking Down Rogue Asteroids
Ed Lu and his B612 foundation are building a space telescope to create
a comprehensive map of the asteroids in Earth’s neighborhood. Named
“Sentinel,” it will fly near the orbit of Venus, about 25 million miles closer
to the sun than Earth. For several reasons, this is an ideal vantage point to
look away from the sun for asteroids passing near Earth. Like the Hubble
Telescope, Sentinel will have a clear view free of the atmosphere and
clouds. Because asteroids are heated by the sun, just like Earth, they are
relatively warm. They are easy to see with infrared detectors: they “glow”
relative to the total cold blackness of space. Sentinel will use special
detectors manufactured by Raytheon in Goleta. Raytheon detectors are
already flying in space, for instance on NASA’s Spitzer Space Telescope.
Sentinel’s design also evolves directly from “Kepler,” another space tele-
scope which has already found numerous planets orbiting stars up to
1,000 light-years away, literally many trillions of miles away and much
more difficult to find than asteroids in our neighborhood.
Private Support For Telescopes
The B612 Foundation is a nonprofit 501(c) 3 organization, the name
inspired by the famed children’s book by Antoine de Saint-Exupéry: B612
is the asteroid home of The Little Prince. The foundation is raising private
funding to build the Sentinel Space Telescope. There are many privately
funded spacecraft, mostly communications satellites, but Sentinel will be
the first privately funded craft to enter deep space, meaning beyond any
Earth orbit. Throughout the history of astronomy, many important tele-
scopes have been privately funded, such as Lick, Yerkes, the Mount Wil-
son telescopes, Palomar and Keck. The tradition continues with two huge
telescopes currently being built, the Giant Magellan Telescope and the
Thirty Meter Telescope. These both have fascinating but nonetheless purely
scientific objectives and are each substantially more expensive than Sen-
tinel’s $450 million price. The only difference between Sentinel and other
private telescopes is that it will be in space instead of on a mountaintop.
Because Sentinel uses existing technology for a well-defined practi-
cal purpose, Ed’s telescope requires no new developments: everything
is already well proven and flying in space. This has an important conse-
quence. Scientific space missions seem to overrun on budget more often
than not. In sharp contrast, satellites for practical uses like communica-
tion are built with fixed price contracts: Dish Network would not stay in
business if the cost of its satellites was not controlled. Similarly, Sentinel
can be accurately priced in advance. Ball Aerospace in Colorado, con-
structors of many important spacecraft including “Kepler,” has contracted
to build this craft for a fixed price.
LOOKING BACK
T
his column describes a spacecraft that does not yet exist that will travel to-
wards the sun. It has a practical purpose: to protect the Earth from asteroids.
A year ago, “Up a.n.d. Out” focused on another spacecraft which had yet to reach
its destination, this one traveling outwards from the sun with a purely scientific mis-
sion. Happily, that spacecraft, NASA’s Mars Rover “Curiosity,” landed safely after the
magazine was published.
This was one of the most complicated spacecraft ever launched and made an
equally complicated landing. It used a heat shield to enter Mars’ atmosphere and
to slow initially, then a parachute opened at supersonic speed. At low altitude the
parachute was released and the Rover was lowered from a “sky crane,” a rocket
powered platform straight out of science fiction. Plenty of people, including this writ-
er, wondered if it would work. In a formidable feat of engineering and organization
by the scientists and engineers of the NASA Jet Propulsion Laboratory in Pasadena,
California, “Curiosity” landed safety. It is now driving across Mars carrying a set of
instruments known as the “Mars Science Laboratory.”
Below, left, is the artist conception published in “Up a.n.d. Out” last year. At right
is a picture of the Rover actually returned from the surface of Mars showing the
excellent prediction the artist made. This is a remarkable self portrait. The Rover has
a camera called the “Mars Hand Lens Imager.” As the name suggests, this works
as a human might use a lens to look at interesting things nearby. And just as you
can take your own picture with a cell phone, the Hand Lens Imager can look back
at the Rover. The complete self-portrait, below, was assembled from numerous
separate pictures.
The portrait shows the Rover near where it landed at the bottom of the Gale
Crater. In due course it will climb the mountain in the background, Aeolis Mons. As
it climbs, it is expected it will cross numerous different exposed geological layers.
The Mars Science Laboratory will not look for evidence of life directly although it
might be found. Instead, it is investigating whether Mars once had the conditions
needed for life. Rock already analyzed contains sulfur, nitrogen, hydrogen, oxygen,
phosphorus and carbon, several key chemical ingredients for life and showing that
ancient Mars could have supported living microbes at the very least.
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