PLEASE NOTE:
*
CCNet 95/2002 - 17 August 2002
------------------------------
(1) ASTEROID HEADS FOR EARTH 'NEAR MISS' - (ANOTHER CASE FOR THE
NEO-HEADLINES POLICE :-)
Ananova, 17 August 2002
(2) MISSHAPEN 800-METRE ASTEROID TO DROP BY EARTH SATURDAY
Vancouver Sun, 16 August 2002
(3) ASTEROID TO MAKE PASS BY EARTH
The Associated Press, 17 Aug 2002
(4) ASTEROID INFORMATION OVERLOAD CAUSES CONFUSION AS MEDIA STILL
REPORT
THAT "2002 NT7 COULD HIT IN 2019"
Canoe Space News, 17 August 2002
(5) ASTEROID FLY-BY VISIBLE FROM EARTH
BBC News Online, 16 August 2002
(6) HOW TO WATCH SATURDAY'S ASTEROID FLYBY
Sky & Telescope, 17 August 2002
(7) SPACEWATCH DETECTION OF "LOST" CONTOUR SPACECRAFT
Spacewatch, 16 August 2002
(8) CONTOUR MAY HAVE BROKEN IN TWO
Astronomy.com, 16 August 2002
(9) COMET-CHASING SPACECRAFT POSSIBLY DESTROYED, NASA SAYS
Space.com, 16 August 2002
(10) COMET EXPLORATION SKYROCKETING: CURIOUS ABOUT ORIGINS,
WORRIED ABOUT
EARTH
Tallahasseee Democrat, 16 August 2002
=============
(1) "ASTEROID HEADS FOR EARTH 'NEAR MISS'" - (ANOTHER
CASE FOR THE
NEO-HEADLINE POLICE :-)
>From Ananova, 17 August 2002
http://www.ananova.com/news/story/sm_652109.html?menu=news.scienceanddiscovery
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
-----------
... AND SOME OTHER CULPRITS
ASTEROID NEARS EARTH
New York Daily News (US), 17 August 2002
SPACE ROCK JUST MISSES
Herald Sun (Australia), 17 August 2002
ASTEROID HEADS FOR EARTH 'NEAR MISS'
The Guardian, 17 August 2002
===============
(2) MISSHAPEN 800-METRE ASTEROID TO DROP BY EARTH SATURDAY
>From Vancouver Sun, 16 August 2002
http://canada.com/vancouver/vancouversun/story.asp?id={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
view.
The best places to see it are far away from the Lower Mainland's
city
lights.
But without a properly mounted telescope or steadily held
high-powered
binoculars, there's not much chance you'll see it even there,
said
Dodge.
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
sky.
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
at www.science.nasa.gov.
© Copyright 2002 Vancouver Sun
==============
(3) ASTEROID TO MAKE PASS BY EARTH
>From The Associated Press, 17 Aug 2002
http://cgi.wn.com/?action=display&article=15197205&template=worldnews/search.txt&index=recent
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
planet.
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
Yeomans.
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
================
(4) ASTEROID INFORMATION OVERLOAD CAUSES CONFUSION AS MEDIA STILL
REPORT
THAT "2002 NT7 COULD HIT IN 2019"
>From Canoe Space News, 17 August 2002
http://canoe.ca/CNEWSSpace0207/0816_asteroid-cp.html
ASTEROID TO MAKE CLOSE CALL WITH EARTH
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
binoculars.
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
object.
"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
================
(5) ASTEROID FLY-BY VISIBLE FROM EARTH
>From BBC News Online, 16 August 2002
http://news.bbc.co.uk/1/hi/sci/tech/2175837.stm
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
asteroid.
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
happening.
Copyright 2002, BBC
================
(6) HOW TO WATCH SATURDAY'S ASTEROID FLYBY
>From Sky & Telescope, 17 August 2002
http://skyandtelescope.com/observing/objects/asteroids/article_697_1.asp
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
rate.
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
telescope.
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
minutes.
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
again.
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.
===============
(7) SPACEWATCH DETECTION OF "LOST" CONTOUR SPACECRAFT
>From Spacewatch, 16 August 2002
http://spacewatch.lpl.arizona.edu/contour.html
Spacewatch
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,
http://spacewatch.lpl.arizona.edu/Jeff/contour.jpg
(250KB)
===========
(8) CONTOUR MAY HAVE BROKEN IN TWO
>From Astronomy.com, 16 August 2002
http://www.astronomy.com/Content/Dynamic/Articles/000/000/000/983sstsp.asp
CONTOUR May Have Broken in Two
The Spacewatch telescope images two objects about where CONTOUR
should
be.
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
said.
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.
==============
(9) COMET-CHASING SPACECRAFT POSSIBLY DESTROYED, NASA SAYS
>From Space.com, 16 August 2002
http://www.space.com/missionlaunches/contour_telecon_020816.html
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
Friday.
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
space.
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
Network.
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
much.
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, Space.com
===============
(10) COMET EXPLORATION SKYROCKETING: CURIOUS ABOUT OUR ORIGINS,
WORRIED
ABOUT EARTH
>From Tallahasseee Democrat, 16 August 2002
http://www.tallahassee.com/mld/democrat/news/nation/3873369.htm
Comet exploration skyrocketing
Scientists curious about our origins, worried about Earth
By Robert S. Boyd
KNIGHT RIDDER TRIBUNE
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
space.
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
spacecraft.
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
cheaply.
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
moons.
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.
Copyright 2002, KNIGHT RIDDER TRIBUNE
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