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Edition 11 - 24 March 1999
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# Hubble surveys 6 spiral galaxies #

22 March 1999

(CNN) -- The Hubble Space Telescope has provided scientists with a
"photo essay" of six spiral galaxies, offering fresh views of star
birth. 

To capture the images, part of a survey of about 100 spiral galaxies,
scientists used the telescope's infrared vision to penetrate the dust
clouds swirling around the centers of the galaxies. 

The pictures showcase different views of spiral galaxies, including a
face-on image of an entire galaxy and a close-up of a core. 

In the images, red corresponds to glowing hydrogen, the raw material
for star birth. The red knots outlining the curving spiral arms in NGC
5653 and NGC 3593, for example, pinpoint rich star-forming regions
where the surrounding hydrogen gas is heated by intense ultraviolet
radiation from young, massive stars. 

In visible light, many of these regions can be hidden from view by the
clouds of gas and dust in which they were born, the Space Telescope
Science Institute said in a statement. 

The glowing hydrogen found inside the cores of these galaxies, as in
NGC 6946, may be due to star birth; radiation from active galactic
nuclei, which are powered by massive black holes; or a combination of
both, astronomers said. Clusters of stars appear as white dots, as in
NGC 2903. 

The galaxy cores are mostly white because of their dense concentration
of stars. The dark material seen in the images is dust. 

The galaxies range in distance from Earth from 19 million light-years
to 161 million light-years. 

The article and the photos at following url:

http://europe.cnn.com/TECH/space/9903/22/hubble.galaxies/index.html


# Stardust spacecraft transmits first image from space #

23 March 1999

(CNN) -- NASA mission controllers were trying to determine what caused
the Stardust spacecraft to enter a "safe" mode during testing of the
navigation camera and transmission of its images to Earth last week en
route toward its rendezvous with Comet Wild-2. 

Stardust's main computer had indicated it was carrying out an
excessive number of functions, triggering fault protection software
that placed the spacecraft in a low-activity state, NASA said. 

When the spacecraft is flown in "safe" mode, all non-critical
activities are halted and the spacecraft points its antenna toward
Earth and awaits new commands. 

Controllers waited until the next telecommunications opportunity on
Friday evening to resume contact with Stardust, and successfully
commanded the spacecraft to resume normal operations, NASA said. 

Mission controllers are performing detailed analysis of the data to
determine what activities or software could have led the spacecraft
computer to trigger fault protection that placed Stardust in its
temporary safe state. 

Last week, the spacecraft successfully exercised the mirror on the
navigation camera for the first time, moving the device outward 90
degrees and back. The mirror will allow the navigation camera to
gather close-up images of heart of Comet Wild-2 without being struck
by debris that will be flying off the comet's nucleus. Stardust
encounters the comet in 2004. 

Mission scientists said were surprised and pleased last week with
Stardust's exceptionally steady orientation in flight. Data from the
navigation camera showed that the spacecraft's "drift," or the
balancing adjustments it makes to maintain its orientation in space,
was about 10 times less than anticipated. 

The spacecraft has also transmitted its first image from space. The
image shows Mars shining brightly against the star background as seen
from the Stardust's view. 

http://europe.cnn.com/TECH/space/9903/23/stardust.update/index.html


# Missile Defense System Debated #

21 March 1999

By ROBERT BURNS AP Military Writer 

WASHINGTON (AP) - Congress has put the Pentagon on a crash course to
building a multibillion dollar defense against missile attacks on the
United States.

But will the system work?

Even the Pentagon, which has spent about $50 billion on missile
defense work over the past three decades, admits it cannot yet say.
After six more years and an additional $10 billion, it hopes to be
able to answer yes.

To understand the uncertainty facing this suddenly popular project,
which the Pentagon calls National Missile Defense, consider that the
high-tech rocket that would shoot down an incoming missile has not
been tested. The first test is due this summer, and the final one not
until 2003.

The missile interceptor is ``the least mature element'' of the
defensive system, Air Force Lt. Gen. Lester Lyles, director of the
Pentagon office coordinating the project, told Congress in February.

If the tests prove successful, the Pentagon intends to build 61 of
these anti-missile missiles, he said. They would be placed at ground
stations in either Alaska or North Dakota, possibly both.

The Senate voted 97-3 last week for a bill that declares the United
States will build a missile defense ``as soon as technologically
possible.'' It set no target date.

On Thursday, the House passed a similar bill that said: ``It is the
official policy of the United States to deploy a national missile
defense.''

The Pentagon's timetable envisions an initial missile defense system
ready for use by 2005. Defense Secretary William Cohen told Congress
on March 2 that the target date - pushed back this year from 2003 -
still carries a ``high risk'' of failure.

That means the current $10 billion estimate for making the system
ready for use in six years may be too low by billions.

Cohen said that in June 2000, the Pentagon will review the progress
and decide whether the time is right to commit to the system. Many
private analysts believe Cohen will conclude that it is too early to
decide.

The initial system could defend all 50 states, but only against a
handful of long-range ballistic missiles fired from a potential enemy
with a poorly developed missile force, such as North Korea.

It would have only ``residual capabilities'' against missiles fired by
an established nuclear power like Russia or China, Lyles said. The
established powers' missiles have more sophisticated means of
overcoming a defense.

David Wright, an analyst at the Union of Concerned Scientists,
disputes the Pentagon's claim that its planned missile defense would
work against the most rudimentary long-range missiles.

``I don't believe it,'' Wright said in an interview.

He contends a country like North Korea that has invested enough to
build an intercontinental ballistic missile would spend what it needed
for effective ``countermeasures,'' decoys and other onboard devices to
fool an American anti-missile system.

Administration officials emphasize that this anti-missile system will
be a far cry from former President Reagan's unfulfilled vision of a
``Star Wars'' shield that could knock thousands of enemy missiles from
the sky.

The Reagan plan included high-powered lasers based in space that would
zap missiles in flight. Adapting that idea, the Air Force is working
on an airborne laser that would be fired from an airplane to ``kill''
a hostile missile during its ``boost phase,'' the earliest stage of
flight. The airborne laser, however, is designed for use against
shorter-range missiles, not as part of a national defense.

The national missile defense now on the drawing board would be based
mostly on the ground. The only space-based element, at least
initially, would be defense satellites that can detect the launching
of a potentially hostile missile and alert ground-based radars of
where the threatening missile is headed.

A ``battle management center,'' probably at the Cheyenne Mountain air
defense complex in Colorado, would evaluate options for shooting down
the incoming missile. When the missile crossed into the range of
ground-based early-warning radars, the radars would confirm flight and
tracking information on the missile. That would allow battle
``managers'' to direct the launch of the interceptor rocket.

Sensors on the interceptor rocket would provide final, precise course
corrections to enable the rocket's ``kill vehicle'' to slam directly
into the target missile, destroying it and exploding its warhead.

Will it work?

``We can't afford to fail,'' Cohen said recently. 

Yahoo! News - AP Headlines

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