CCNet 95/2002 - 17 August 2002

    Ananova, 17 August 2002

    Vancouver Sun, 16 August 2002

    The Associated Press, 17 Aug 2002

    THAT "2002 NT7 COULD HIT IN 2019"
    Canoe Space News, 17 August 2002

    BBC News Online, 16 August 2002

    Sky & Telescope, 17 August 2002

    Spacewatch, 16 August 2002



     Tallahasseee Democrat, 16 August 2002


>From Ananova, 17 August 2002

An asteroid half-a-mile across is set to come close enough to Earth
tonight to be seen through small telescopes or binoculars.

The 800-metre wide space rock, named 2002 NY40, will pass at a distance
of 329,000 miles.

Although slightly further away than the Moon, it counts as a "near miss"
by astronomical standards.

The asteroid will be 100 times fainter than the naked eye can see. But a
small four inch telescope will be powerful enough to pick it up.

Sharp-eyed observers might be able to spot it with a pair of binoculars,
said Robin Scagell from the Society for Popular Astronomy.

Despite its size the asteroid will look like a fast-moving faint star.
It will cross the sky at about the same speed as the minute hand of Big
Ben, seen from the foot of the clock tower.

Mr Scagell said: "This will be a fascinating event. It may not be
spectacular but it is very unusual to see a space rock up close like
this - usually you have to wait for hours or days to detect any movement
in the sky, apart from such things as meteors and satellites.

People looking for the rock will need a detailed map of its track,
showing stars at least as faint as the asteroid. Details can be obtained
from the Society For Popular Astronomy website.

The asteroid passes Vega, the brightest star in the summer sky, at about
4.30am BST.

Copyright 2002, Ananova


New York Daily News (US), 17 August 2002

Herald Sun (Australia), 17 August 2002

The Guardian, 17 August 2002

>From Vancouver Sun, 16 August 2002{FE53A392-7078-454A-9B9B-3D3B700784D2}

Hayley Mick 

Asteroid 2002 NY40 will zoom past Earth Saturday night at a mere
binocular-view's distance.

But if you want scare stories about asteroids wiping out Earth, you'll
have to rent Deep Impact, Armageddon or Judgment Day.

"There is zero chance of this hitting the Earth," said David Dodge, an
astronomer at the H.R. MacMillan Space Centre in Vancouver.

The real-life asteroid will race past at a distance of more than 500,000
kilometres. That's about 100,000 kilometres past the moon's orbit.

"There's nothing we could do about it anyway," said Dodge, adding that
if the asteroid was en route towards the Earth, we'd only have about
three hours warning.

The asteroid, a misshapen rock about 800 metres in diameter, could do
fair bit of damage if it were to hit Earth.

Nothing like the asteroid that is believed to have snuffed the dinosaurs
65 million years ago after carving a crater 180 kilometres wide in the
Gulf of Mexico. That asteroid -- scientists weren't around at the time
to give it a name -- was about 10 times the size of NY40.

An even larger asteroid hit the Sudbury, Ont. area 1.8 billion years
ago, punching a 250-kilometre-wide hole in the ground.

NY40 won't come anywhere that close, but asteroid fans should head out
of town as it orbits by. Not to escape the asteroid, but for a better

The best places to see it are far away from the Lower Mainland's city

But without a properly mounted telescope or steadily held high-powered
binoculars, there's not much chance you'll see it even there, said

To locate it in the sky, first line up Vega, the brightest star in a
triangle of three stars visible to the naked eye in the summer evening

If you look below the Big Dipper's handle, Vega is located in roughly
the seven o'clock position.

The asteroid, which will pass to the east of Vega, will be visible with
powerful binoculars or small telescopes around 11 p.m. Saturday.

The asteroid will appear as a speck of light, moving about eight degrees
per hour across the telescope field.

Within four hours, the asteroid will have turned its darkened side to
Earth and begin to disappear from sight.

According to Dodge, the speedy asteroid will become as faint as Pluto
within 24 hours.

Scientists are as eager as astronomy buffs and doomsayers to observe the
asteroid's passing.

"We want to know which one's got our name on it, then we might be able
to do something about it," said Dodge.

Asteroid 2002 MN, the size of a football field, went by Earth in June at
a distance of 120,000 kilometres, one of the closest near-misses on
record. But the flyby went undetected days after the event.

This time, scientists are ready. A team of observers at a radar station
in Puerto Rico will bounce radio waves off NY40 to create a 3D map of
the asteroid and learn more about its makeup.

Asteroids are rich in minerals, which could benefit Earth.

For more information about asteroid 2002 NY40, check the NASA Web site

Copyright  2002 Vancouver Sun


>From The Associated Press, 17 Aug 2002
WASHINGTON (AP) - An asteroid will pass close enough to the Earth to be
viewed with binoculars on Saturday night, but astronomers said there is
no immediate danger that the half-mile-wide space rock will hit the

The asteroid, known as 2002 NY40, was discovered July 14. Astronomers
said Friday that it will zip by about 350,000 miles from the Earth,
about 1.3 times farther away than the moon.

It is expected to be faintly visible by binoculars or by telescope after
sunset on Saturday to about 3 a.m. EDT Sunday as it appears to pass near
the star Vega and clip through the constellation Hercules.

Don Yeomans, director of NASA's Near-Earth Object Program at the Jet
Propulsion Laboratory in California, said an asteroid passage within
view of the Earth is uncommon.

``Flybys like this happen every 50 years or so,'' Yeomans said in a
statement released by NASA. The last known occurrence was on Aug. 31,
1925, when a similar-sized asteroid, called 2001 CU11, passed by just
outside the orbit of the moon. That flyby was unrecognized until 77
years later, when modern astronomers detected the space rock and
backtracked its orbit.

Since astronomers know 2002 NY40 is coming, they are preparing a
reception. A giant radar beacon at the Arecibo observatory in Puerto
Rico will bounce signals off the asteroid as it whizzes past. The return
radar signal will help astronomers learn the shape of the space rock and
help plot its future path through space.

"At present we know there's little risk of a collision with 2002 NY40
for decades," said Jon Giorgini, a member of a JPL radar observation
team. "When the Arecibo radar measurements are done, the orbit
uncertainties should shrink by more than a factor of 200. We'll be able
to extrapolate the asteroid's motion hundreds of years into the past and
into the future."

At its closest approach to Earth early Sunday, the asteroid will shine
at a stellar magnitude of 9, about one-sixteenth the brightness of the
faintest star visible without a telescope.

Yeomans said asteroids are generally difficult to see because they are
mostly black, like charcoal.

``The most common ones - carbon-rich C-type asteroids - reflect only 3
to 5 percent of the light that hits them,'' he said. ``Metallic
asteroids, which are somewhat rare, reflect more, 10 to 15 percent.''

Astronomers are uncertain of the composition of 2002 NY40, but they
should know after taking readings with ground-based telescopes, said

The path followed by 2002 NY40 will make it relatively easy to spot with
binoculars or telescopes. To an Earth observer, it will appear to fly
past Vega, the brightest star in the summer nighttime sky. It is
expected to appear as a speck of light moving at about 8 degrees an
hour, NASA said. The best viewing will be from the Northern Hemisphere,
starting just after sunset on Saturday in North America and during the
hours just before dawn on Sunday in Europe.

Vega, the bright star, is in the constellation Lyre. It will be slightly
to the west of a point directly overhead at 11 p.m. EDT, according to
JPL spokesman Guy Webster. The asteroid will be moving westward, passing
near Vega and then on across the right knee and elbow of the figure in
the constellation Hercules, he said.

Experts say the best way to spot the space rock is to hold focus on an
area of the sky where it is expected to pass. It will appear to be a
fast moving star.

The bright side of the asteroid will face the Earth early in its
passage, giving observers a look at its fullest sunlit phase. But as it
moves on, the dark side will come into view and the asteroid will
noticeably dim and then disappear from view, NASA said.
Copyright 2002, AP

    THAT "2002 NT7 COULD HIT IN 2019"

>From Canoe Space News, 17 August 2002


TORONTO (CP) -- Astronomers monitoring the largest asteroid to travel so
close to Earth in 77 years say the speeding chunk of rock is getting
brighter and should be visible on Saturday to anyone with a telescope or

Researchers from Canada, the Czech Republic and the United States have
been monitoring the 800-metre-wide asteroid all week, watching it as it
hurtles toward the planet at 21 kilometres per second.

The asteroid, the size of eight football fields, is expected to miss the
Earth by about 530,000 kilometres late Saturday night -- the largest
asteroid to be so close to the planet since 1925.

"It's getting brighter," said Peter Brown, an astronomy professor at the
University of Western Ontario in London, Ont., who is monitoring the

"But we haven't been able to see much of it."

Brown said his team's research has been plagued with cloudy night skies,
but said he's hoping to get a better view of the asteroid -- known as
2002 NY40 -- before it travels out of sight some time Sunday morning.

So far, researchers have been able to tell that the asteroid is rotating
once around every 20 hours. They're still trying to determine what
minerals the asteroid is made of.

"We probably won't know the mineralogical makeup of it until the end of
August," Brown said.

Anyone with a small telescope or a set of binoculars should be able to
find the asteroid south of the Big Dipper and near the bright star of
Vega at around 11 p.m. Saturday.

Residents of the Northern Hemisphere are expected to have the best view
of the object, as long as the clouds don't get in the way.

Meanwhile, astronomers are also carefully monitoring a newly discovered
two-kilometre-wide asteroid to see whether it's on a collision course
with Earth.

Researchers say that asteroid -- known as 2002 NT7 -- could hit the
Earth on Feb. 1, 2019.

Copyright 2002, CNews


>From BBC News Online, 16 August 2002
A close encounter with a small asteroid this weekend could be viewed
with binoculars or a small telescope, say experts.

The space rock, 800 metres (half a mile) across and designated 2002
NY40, will make its closest approach on Sunday.

The opportunity for amateur skywatchers to get such a close-up view of
an asteroid occurs only once every half-century.

The nearest the asteroid will get is within 530,000 kilometres (330,000
miles) - slightly farther away than the Moon.

Future pass

Its track in the sky will pass close by the bright star Vega and through
the constellation of Hercules.

It will be significantly dimmer than even the faintest star visible with
the naked eye.

European skywatchers will catch their best glimpse in the early hours of
Sunday. For viewing from North America, the best time to watch will be
on Saturday evening.

Scientists will be able to use the close approach to plot the course of
the asteroid over the years to come.

They say there is a minute risk - one in 500,000 - that the rock could
strike Earth in 2022, but the new measurements could show it will
definitely miss us.

Drawing skills

Jay Tate, from the Spaceguard UK observatory in Powys, said that with a
little effort, it should be possible to detect the movement of the

He told BBC News Online: "People should look at the right area of the
sky through their binoculars, and make a rough drawing of the position
of all the bright objects.

"Then they should look again five minutes or so later and see which of
them has moved.

"This asteroid won't look anything like a normal shooting star, or even
a satellite.

"It's not groundbreaking science for us, but this is an opportunity for
thousands of amateur astronomers to see something like this."

Spin rate

He said that measurements taken by experts might show the rate at which
the rock was spinning in space, giving clues to its composition.

Other astronomers may also be able to produce three-dimensional maps of
its surface.

The asteroid fly-by follows last month's reports of another, bigger,
rock, called 2002 NT7, which scientists speculated might be a candidate
for colliding with the Earth in 2019.

Further data revealed, however, that there was no chance of this
Copyright 2002, BBC


>From Sky & Telescope, 17 August 2002

By Roger W. Sinnott

For help in locating asteroid 2002 NY40 on August 17-18, Sky & Telescope has
prepared four (PDF) finder charts (see page 2). S&T: Roger Sinnott and
Steven Simpson.

On Saturday night, August 17-18, a recently discovered asteroid will pass
close enough to Earth to be easily spotted in small telescopes or even
binoculars. The latest calculations by the Minor Planet Center in Cambridge,
Massachusetts, indicate the flyby will bring it to within 527,000 kilometers
(327,000 miles) of Earth, just outside the Moon's orbital distance.

Astronomers first detected this object, designated 2002 NY40, on July 14th
with the 1-meter LINEAR telescope in New Mexico. It was then only 19th
magnitude and appeared nearly stationary in western Aquarius, brightening
steadily on an in-bound path toward Earth. Finally this week, with the flyby
fast approaching, the asteroid began moving northwest at an ever-increasing

Judging by its brightness, this interloper is roughly 500 meters (0.3 mile)
across. But detailed photometry by Lenka Sarounova (Czech Republic), Sergio
Foglia (Italy), and David DeGraff, William Holliday, and Walter Cooney (USA)
already shows it to have an irregular shape. Using their observations, Petr
Pravec (Ondrejov Observatory) finds that 2002 NY40 rotates in 20 hours and
varies by more than a magnitude. The light-curve amplitude "indicates that
the asteroid is an elongated object with an equatorial-axis ratio greater
than 2:1," Pravec reported to the Minor Planet Mailing List August 9th.

Almost immediately after its discovery in July, astronomers determined that
there was no danger of 2002 NY40 striking Earth during this flyby. In
addition, both NEODyS, operated by the University of Pisa, and NASA's
Near-Earth Object Program quickly ruled out an impact during the coming
century. But the encounter affords Earth-based astronomers a rare chance to
study an asteroid at very close range, however briefly.

Where and How to Look

On the night of Saturday, August 17-18, 2002 NY40 should reach magnitude 10
or even 9 during the period when it is well placed for viewing from Europe,
Africa, and the Americas. Although it might be spotted in binoculars, small
telescopes should give a more satisfying view by magnifying the object's
apparent motion. Skywatchers should be able to perceive this motion any time
it glides near a background star. When the asteroid is closest to Earth at
around 7:47 Universal Time on the 18th, it will be traveling eastward at a
breezy 8 arcminutes per minute!

For help in locating the asteroid that night, Sky & Telescope has prepared
four finder charts (A, B, C, and D) that span a 60 arc across the heavens
from Sagitta through Vulpecula, Cygnus, Lyra, and Hercules. Each chart is a
PDF file; these are readable on any computer using Adobe's free Acrobat
Reader software, version 3.0 or later, and can be printed out for use at the

Chart A is mainly of use to observers in Europe and Africa, with tracks
plotted for the period 20:00 UT (on the 17th) to 01:30 UT on the 18th.

Chart B includes the start of tracks suitable for North American viewers,
plotted from 1:30 to 4:30 UT.

Chart C shows the continuation of the asteroid's path as viewed from Boston
and Los Angeles between 4:10 and 6:10 UT.

Chart D shows the the final portion of the track for North American viewers
and concludes at 7:40 UT.

Because of the parallax effect, the asteroid's exact trajectory depends on
your geographical location. Tracks for several widely separated cities are
shown, and you can estimate the track for your own location relative to
those shown. (For example, the track for Denver would lie between the tracks
shown for Boston and Los Angeles, somewhat nearer the latter.) Each plotted
track covers only the period when the asteroid is at least 10 above the
horizon in a fully dark sky at that location. Our plots are based on
astrometric measurements received by the Minor Planet Center through August
11th. Each individual track should be quite reliable, but the object's
arrival time at a specific point along a track is still uncertain by 1 or 2

To catch sight of this fleet visitor, the best strategy is to pick out a
star near which the asteroid will pass at a specific UT. About 10 minutes in
advance, park your telescope on that star and watch for the asteroid to come
by. If you miss it, find another plotted star farther down the track and try

Keep in mind that the asteroid will be slightly fainter than the stars shown
in our plots, yet still quite easy to see in a small telescope. A mere 24
hours after it goes by, however, the object will plunge hopelessly beyond
reach of Earth-based telescopes as it heads closer to the Sun. (We will then
be viewing its unilluminated side, which explains why it becomes so faint,
so fast.)

 - - - - - - - - - - - - - - - - - -
Sky & Telescope senior editor Roger Sinnott will be observing this celestial
visitor from his backyard observatory in a Boston suburb.

Copyright 2002 Sky Publishing Corp.


>From Spacewatch, 16 August 2002

Lunar and Planetary Laboratory
University of Arizona
Tucson, Arizona

2002 August 16

Spacewatch detection of "lost" CONTOUR Spacecraft

In this subtracted image in which moving objects are revealed by
pairs of images, one dark and one bright, taken by Jim Scotti with
the Spacewatch 1.8-meter telescope on Kitt Peak on 2002 August 16,
there are two parallel trails near one of the predicted positions
of the CONTOUR spacecraft, radio contact with which had been lost
the day before following a commanded large velocity impulse maneuver.

These trails were discovered and measured by Jeff Larsen during
his re-examination of the data. The curvature of the trails is a
natural characteristic of the drift scanning process at this high
declination. The images are oriented with north at the right and
west up.

The positive images are the earlier time. The fact that there are
two trails indicates that the spacecraft must have separated into
two pieces that are still moving in nearly parallel directions.

Media: Please indicate (c) 2002 The Spacewatch Project, Lunar
and Planetary Laboratory, The University of Arizona in any
reproductions of this image.

View Image, (250KB)


>From, 16 August 2002

CONTOUR May Have Broken in Two
The Spacewatch telescope images two objects about where CONTOUR should

by Vanessa Thomas

Soon after the Comet Nucleus Tour (CONTOUR) fell silent Thursday morning
following a planned rocket firing, mission managers sent out a call to
observatories around the world to help look for the spacecraft. Poor
weather plagued Mauna Kea and LINEAR's observing location in New Mexico,
but for the 1.8-meter Spacewatch telescope in Arizona there were clear
skies. Early Friday morning, Spacewatch astronomers spotted what
appeared to be CONTOUR - and then noticed a second object nearby, moving
in the same direction.

According to mission director Robert Farquhar, who spoke to reporters
Friday afternoon, the CONTOUR team had "some optimism up until this
time." But he added, "Looking at this image, I don't feel very good
about it."

According to CONTOUR team member David Dunham, the pair of objects are
about 0.6 degree away from where CONTOUR was expected to be at the time
of the observation. Spacewatch's image of the parallel-moving objects,
along with the lack of communication from CONTOUR, suggests the
spacecraft may have split in two.

The Spacewatch image offers a tiny ray of hope, though. One of the two
objects is brighter than the other. Perhaps just a piece of the
spacecraft - such as insulation - broke off, Farquhar hoped aloud on
Friday. But he admits that the conjecture is "grasping at straws."

At 4.49 a.m. August 15, CONTOUR was expected to fire its rocket and
boost itself out of Earth orbit and toward a 2004 rendezvous with Comet
Encke. At the time, the spacecraft was out of reach of Deep Space
Network (DSN) antennae. CONTOUR team members encouraged amateur
observers to observe CONTOUR before and after the firing, but at the
time, only observers in Australia, New Zealand, and the western Pacific
were able to view the spacecraft. According to Dunham, the CONTOUR team
hasn't received any positive reports from those parts of the world.

About 45 minutes after the firing, the team expected to hear from
CONTOUR, but the DSN never found a signal. Several problems might have
prevented the acquisition of CONTOUR's signal, so without too much
worry, engineers immediately began running backup plans. Friday morning
the team hoped a pre-programmed maneuver to turn CONTOUR about 40
degrees would improve the spacecraft's signal. But after the time came
and went with still no sign, "we got rather concerned," said Farquhar.

Then came the Spacewatch image. When the objects were spotted, they were
250 kilometers (155 miles) apart and about 400,000 km (250,000 miles)
from Earth. The mission director calls the image "a little
discouraging," but noted that if the objects are indeed parts of
CONTOUR, their distance from us indicates the spacecraft successfully
fired its rockets and left Earth orbit.

And Farquhar still keeps a bit of room for optimism. He pointed out that
the NEAR spacecraft also went quiet for a couple days in 1998 before it
was successfully recovered and sent on its way toward asteroid Eros. "We
always have hope that things are going to turn out all right," Farquhar
Throughout the weekend, the CONTOUR team will continue its attempts to
contact the spacecraft and find out what happened to it. The group also
plans to use the Arecibo radio telescope in Puerto Rico to try to detect
the spacecraft by radar. You can check the CONTOUR website for updates.

Copyright 1996-2002 Kalmbach Publishing Co. 


>From, 16 August 2002

Comet-Chasing Spacecraft Possibly Destroyed, NASA Says
By Robert Roy Britt

The comet-chasing CONTOUR spacecraft appears to have broken into two
pieces sometime after its course-altering rocket engine fired early
yesterday morning, a NASA official said Friday evening.

A ground-based telescope photograph of two unknown objects about 155
miles (250 kilometers) apart appeared to be pieces of CONTOUR (Comet
Nucleus Tour). The objects were spotted along the path the spacecraft
would have traveled had the engine fired.

"We haven't given up by any means, but the news is very discouraging,"
said Mission Director Robert Farquhar of the Applied Physics Laboratory
(APL) of Johns Hopkins University. "Although this is not conclusive, it
is not very encouraging."

Artist's rendering shows the planned firing of CONTOUR's STAR 30BP
solid-propellant rocket motor, designed to send the craft beyond Earth's
orbit on Aug. 15, 2002. The craft would have been spinning at 60
revolutions per minute. The 50-second engine burn was meant to inject
Contour into a solar orbit, on course to intercept comets.
In this subtracted image in which moving objects are revealed by pairs
of images, one dark and one bright, taken by Jim Scotti with the
Spacewatch 1.8-meter telescope on Kitt Peak on Aug. 16, there are two
parallel trails near one of the predicted positions of the CONTOUR
spacecraft. These trails were discovered and measured by Jeff Larsen.
Farquhar said more investigation was needed to confirm whether or not
the objects were parts of CONTOUR.

There was no clear cause for the possible accident, but Farquhar said
the craft's engine had almost certainly fired and that the probe was no
longer in Earth orbit. Officials had said Thursday the craft might never
have left the planet's gravitational grip.

Despite the possible catastrophe, a concerted search effort will
continue at least through Monday. NASA's Deep Space Network and the
Arecibo Observatory will scan the skies for radio signals in the hopes
that the 2,138-pound (970-kilogram) craft phones home and reports it is
healthy and heading for a comet rendezvous.

Other telescope will continue visual searches for the spacecraft.

"It's not the best evening for the CONTOUR mission," Farquhar said
during a teleconference with reporters that began around 5:30 EDT

The mission director said he had remained confident most of Thursday
that the spacecraft was in good health. "Up until a little while ago I
had a whole lot of hope," he said.

What should have happened

APL built CONTOUR and leads the $159 million mission under NASA
direction. It is a Discovery-class mission, designed at relatively low
cost for a highly specific task.

The craft launched July 3 into an elliptical orbit around Earth. At 4:49
a.m. EDT Thursday the probe was supposed to fire its STAR 30 BP rocket
motor to shoot it out of Earth's gravitational pull. This plan saved $10
million compared to launching the spacecraft directly from Earth to deep

About 45 minutes later, CONTOUR should have sent a signal to be picked
up by NASA's Deep Space Network of radio antennas around the world. No
signal was ever received.

The craft's mission is to take close-up photos and gather other data on
two or possibly three comets.

On the off chance that CONTOUR is in good health but simply cannot
transmit, it could be on its way to comet Encke, it's first target. If
so, the only likely way to detect it would be through the Deep Space

It is not unheard of for spacecraft to go quiet at critical junctures,
only to turn up healthy later.

In fact, an earlier APL-run mission, the Near Earth Asteroid Rendezvous,
disappeared in 1998 after a course-correcting burn did not occur.
Contact was re-established two days later and the craft completed a
successful mission.

"We got our hopes raised a couple of times," Farquhar said of false
readings that suggested CONTOUR was calling back. "It's a roller coaster
when this happens."

Just when things were going well

A loss would come just as NASA has re-emerged from some of its darkest
days and criticism over back-to-back mission disasters in 1999.

In that year, Mars Climate Orbiter failed to go into orbit around the
Red Planet because of a human mixup between metric and English units.
And the Mars Polar Lander failed to safely reach the surface. Both
missions were managed by NASA's Jet Propulsion Laboratory.

Critics faulted NASA's shift to more and cheaper missions as a
contributing cause to the failures. Even NASA officials admitted as

But the agency gained renewed vigor and purpose with the success of the
recent Odyssey mission to Mars.

While Mars missions are typically planned for launch every couple years,
comet missions are rare. Astronomers say CONTOUR would help them map out
the diversity of these frozen objects, which are thought to harbor
material that's gone unchanged since the birth of the solar system.

The plan was to examine comet Encke in November 2003 and
Schwassmann-Wachmann 3 in June 2006. The two comets are thought to be
very different.

"It would be pretty sad" if the craft does not complete its mission,
said Donald Yeomans, a comet expert at JPL. "If we had to go without it
we would be losing a significant amount of comet science."

If CONTOUR is lost, a replacement mission -- if ever approved -- could
take several years or even a decade or more to get off the ground.

Copyright 2002,


>From Tallahasseee Democrat, 16 August 2002
Comet exploration skyrocketing
Scientists curious about our origins, worried about Earth
By Robert S. Boyd

WASHINGTON - For millions of years, comets have been swooping past Earth
and occasionally bashing into us. Now earthlings are turning the tables
on those luminous, mysterious, potentially dangerous visitors from outer

No less than four spaceships are currently on their way - or soon will
be - to five or six nearby comets. Starting in January, they will take
close-up pictures, collect samples, punch a hole in and even land on the
surface of their assigned targets.

"This is a golden decade for cometary science," said Donald Yeomans, who
tracks comets and asteroids at NASA's Jet Propulsion Laboratory in
Pasadena, Calif.

Comets are chunks of rock and ice surrounded by glowing clouds of gas
and dust that come from the outer edge of the solar system. Asteroids
are fragments of rocks or metal that orbit the sun, largely between
Jupiter and Mars.

Two NASA comet missions, STARDUST and CONTOUR, have already been
launched. A European spaceship, ROSETTA, will follow in January, and a
third American project, DEEP IMPACT, a year later.

On Thursday, NASA announced it lost contact with the $159 million
CONTOUR spacecraft, and scientists were trying to figure out what
happened when the robotic probe was to have left Earth orbit.

CONTOUR was programed to fire its motor at 1:49 a.m. PDT, boosting it
from orbit. At the time, the octagonal spacecraft was about 140 miles
above the Indian Ocean.

NASA's Deep Space Network of antennas was to have picked up a signal
from CONTOUR at 2:35 a.m. By late morning, the antennas in California,
Australia and Spain still had not picked up a signal from the

Security driving effort

Why this sudden surge of scientific interest in comets, which have
intrigued and sometimes terrified human beings in the past?

One reason, Yeomans pointed out, is home-planet security. We live in a
veritable shooting gallery of comets and asteroids that periodically
pummel the Earth, such as the object that hastened the death of the
dinosaurs 65 million years ago.

"These things can run into us," Yeomans said. "If one of them has our
name on it, we've got to know what they're made of." Such information
could be crucial for any attempt to deflect a comet or asteroid from
colliding with Earth.

Basic scientific curiosity also is driving the comet hunt, especially
now that modern technology makes it possible to visit comets relatively

The four missions will cost between $150 million and $325 million apiece
- peanuts for space projects when compared with $1.5 billion for a major
planetary explorer such as GALILEO.

"There's an awful lot of high-class science waiting to be done," said
Tom Morgan, who directs the three U.S. comet hunts from NASA
headquarters in Washington.

According to Joseph Veverka, an astronomer at Cornell University in
Ithaca, N.Y., and chief scientist for the CONTOUR mission, comets are
among the solar system's biggest mysteries. "We really have more ideas
about comets than facts," he said.

A trillion or more of these ghostly objects are thought to hang out in
the deep cold beyond the fringes of the solar system. Periodically,
gravity nudges one of them into a long, looping voyage past the planets
and around the sun.

Because they are so far away, comets are thought to preserve the
original gas and dust left over from the formation of the solar system
4.5 billion years ago. Astronomers regard them as virtual time machines
that enable them to study the raw materials of our sun, planets and

Furthermore, scientists think comets brought huge quantities of water
and carbon-based molecules to Earth during the era of heavy bombardment,
when our planet was young.

Some theorists speculate that the cometary molecules may even explain
how life got started on Earth. "We may really be the progeny of comets,"
Veverka wrote in the journal Science last month.

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