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(meteorobs) Excerpts from "CCNet 9/2001 - 17 January 2001"




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From: Peiser Benny <B.J.Peiser@livjm.acdot uk>
To: cambridge-conference <cambridge-conference@livjm.acdot uk>
Subject: CCNet, 17 January 2001
Date: Wed, 17 Jan 2001 12:49:04 -0000

CCNet 9/2001 - 17 January 2001
------------------------------


(1) NASA AIMS TO BLAST COMET TO STUDY SOLAR SYSTEM
    Oliver Morton <abq72@dial.pipex.com>

[...]

(3) LUSTING AFTER A LANDING ON EROS      
    Weired Magazine, 16 January 2001

[...]


========================================================

(1) NASA AIMS TO BLAST COMET TO STUDY SOLAR SYSTEM

>From Oliver Morton <abq72@dial.pipex.com>

Benny -- this is the first time I've seen Deep Impact talked of -- albeit in
passing -- as having some implications for planetary defence. Maybe I just
haven't been paying attention.

oliver morton
abq72@dial.pipex.com

NASA Aims to Blast Comet to Study Solar System
http://www.nytimes.com/2001/01/17/science/science-space-chile-d.html

January 17, 2001

By REUTERS

SANTIAGO, Chile - NASA scientists aim to blast a comet with a copper
projectile to learn about the formation of the solar system as part of a
$270 million project funded by NASA, the head of the project said on
Tuesday.

The project, called Deep Impact and which will cause an explosion capable of
destroying a small town, would be the first space mission to probe inside a
comet, whose primitive core could reveal
clues about evolution of the solar system.

"All our studies of comets look only at the surface layer. Our theoretical
models tell us the surface has changed, and only the interior has the
original composition. So our main goal is to
compare the interior with the surface," the project's director, Michael
A'Hearn, told reporters.

Scientists chose copper, Chile's No. 1 export, because it is less likely to
interfere with the materials inside the crater.

In January 2004, a rocket would launch from Cape Canaveral, Florida, a
spacecraft that would orbit the sun. In July 2005 the spacecraft would
separate from a battery-powered, copper projectile that would collide with
the comet 24 hours later at a velocity of 6 miles (10 km) per second.

It would produce a crater the width of a football field and up to 100 feet
(30 meters) deep.

The spacecraft would observe the composition of the crater's interior, while
telescopes on Earth would monitor the impact.

The project also aims to see if scientists can alter the orbit of a comet to
protect the Earth from falling matter. The impact would alter the comet's
orbit by a "just barely measurable" 62 to 620 miles (100 to 1,000 km),
A'Hearn said.

The project would blast the Comet Tempel 1, which was discovered in 1867 and
is a little less than Earth's distance from the sun, he said. It was chosen
because its size, rotation and trajectory favor the project and because the
collision would be observable from Earth.

In February, NASA will carry out a preliminary design review to see if the
project can succeed. 

Copyright 2000 The New York Times Company

========================================================

(3) LUSTING AFTER A LANDING ON EROS      

>From Weired Magazine, 16 January 2001
http://www.wired.com/news/technology/0,1282,41119,00.html

by Lisa Nadile 

Take these ingredients: A spinning rock about 21 miles in length and covered
with small boulders and craters. An automobile-sized craft that weighs 1,775
pounds. No fuel. A blindfold. Johns Hopkins space jockeys. A dash of
adventure. What do you have? Not the script to another bad space disaster
movie, but an actual scientific endeavor that aims to land a vehicle on a
asteroid. 

"You got the picture. We're winging it," said Dr. Robert Farquar, NEAR
Shoemaker mission director at Johns Hopkins University Applied Physics
Laboratory in Laurel, Maryland. 

NEAR stands for Near Earth Asteroid Rendezvous. Shoemaker is for the late
Eugene "Super Gene" Shoemaker, a world-renowned geologist at the U.S.
Geological Survey in Flagstaff, Arizona, and a close friend of Farquar. 

The asteroid is named Asteroid 433 Eros, and the "rendezvous" originally
meant to fly around the rock, take some pictures and then crash. The mission
was to last a year, then on Feb. 12 come to a rather abrupt end. 

That mission has changed somewhat. Now they're actually trying to land the
darn thing -- a challenge Farquar says has about a 1 percent chance of
success. 

"It'll end up on the surface one way or another," Farquar said. "I like the
description of landing on a moving aircraft carrier, if it's spinning and
the deck is coming up at you." 

Admittedly the landing is a piloting exercise for the John Hopkins
University based team. 

"This exercise in landing on small bodies like Eros is applicable. I can see
asteroids used as temporary quarters for traveling larger distances," he
said. "We'll slow the NEAR Shoemaker down and try the landing at about
jogging speed." 

However, there is more to the landing than just derring-do. 

"This is the first time we've taken pictures this close of anything since
the moon and a few small areas of Mars," said Dr. Clark Chapman, a NEAR
imaging team member and a geologist for the Southwest Research Institute in
San Antonio, Texas. 

The photos taken during the landing are expected to be 10 times better than
those taken from orbit. "We want to find out what it's made of," he said. 

NEAR Shoemaker totes a range of scientific tools. A magnetometer to check
for magnetic materials like those found in meteorites. An X-ray/Gamma-ray
spectrometer for measuring silicon, magnesium, iron, uranium, thorium and
potassium. A near-infrared spectrometer to map the mineral composition of
the surface by measuring the spectrum of sunlight reflected by the asteroid.
A multispectral camera and a laser rangefinder to measure the clog
shoe-shaped EROS landforms and colors. And the craft has performed
experiments to evaluate the density of Eros. 

"When we looked at the moon's lunar surface we saw a few scattered boulders
but mostly the moon was covered with small craters, but EROS is covered with
small boulders and hills, he said. 

"Asteroids are strange places from what little we know. Eventually we will
mine and take samples and deal with what they can tell us," Dr. Chapman
said. "With this kind of imaging, it's no different from taking a camera and
going hiking, expect we're hiking into Wonderland. We didn't know what to
expect." 

The NEAR Shoemaker doesn't have to land, but the activities of the space
jockeys like Farquar is all gravy, Chapman said. The plans for landing were
a surprise to many. "I thought about doing this early on, but I didn't have
the nerve to say anything," Farquar said. 

"He is mischievous and intriguing. NASA is extremely risk-adverse ... and a
bit straitlaced. Farquar is a breath of fresh air," Chapman said. Launched
from Cape Canveral Air Station in 1996, NEAR's arrival at Eros on
Valentine's Day of last year was no accident. 

Eros is 1.3 astronomical units from the Sun, where Earth is 1 astronomical
unit. It is classified as a near-Earth asteroid, which means it travels
within 121 million miles of the Sun. Scientists theorize that these types of
asteroids are from the main belt between Mars and Jupiter. 

The NEAR Shoemaker adventure is not only about the adventurers who man our
space programs, but about trying the impossible. Farquar, Chapman and the
rest of the NEAR Shoemaker team engage in friendly competition with their
NASA counterpart, the Jet Propulsion Laboratory. But they all want the same
thing. Repeat after me: To boldly go ... 

Copyright ) 2001 Wired Digital Inc., a Lycos Network site. All rights
reserved. 

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