Accessibility Help

Skip
to content

Skip
to bbc.co.uk search

Low
graphics

Help

Access
keys help

Search term

Explore the BBC

BBC News Updated every
minute of every day

One-Minute World News

News
Front Page

Africa

Americas

Asia-Pacific

Europe

Middle East

South Asia

UK

Business

Health

Science &
Environment

Technology

Entertainment

Also in the
news

-----------------

Video and
Audio

-----------------

Have Your
Say

In Pictures

Country
Profiles

Special Reports

Related BBC sites

Sport

Weather

On
This Day

Editors' Blog

BBC World Service

Site Version

UK
Version

International
Version

About the
versions

Page last updated at 12:03 GMT,
Thursday, 12 February 2009

E-mail this to a friend

Printable version

Sat collision highlights growing threat

By Paul Rincon
Science reporter, BBC News

There are some 17,000 man-made objects orbiting
our planet

The collision between a US and Russian satellite in space
highlights the growing importance of monitoring objects in
orbit.

It also shows that there are still major capability gaps in
current systems set up for this task.

There are about 17,000 man-made objects orbiting Earth, and the
tally is constantly increasing, which in turn raises the risk of
collisions between objects.

Nevertheless, experts say the incident was extremely unusual. The
vastness of space means the probability of two intact satellites
colliding is very low indeed.

Intact satellites share Earth's orbit with everything from spent
rocket stages and spacecraft wreckage to paint flakes and dust.

The diffuse mist of junk around our planet is the legacy of 51
years of human activity in space.

At orbital velocities, even small pieces of space debris can
cause serious damage to spacecraft.

And both the Americans and Russians have networks of tracking
stations to monitor objects.

The US military operates 25 centres around the world involved in
space surveillance, including one at RAF Fylingdales in the UK.

Debris field

Radars are generally used to track objects in low-Earth orbit,
while optical telescopes are used to observe objects further away
from the Earth.

Radio frequency technology - a form of electronic surveillance -
can be used to assess whether or not satellites are active.

China and the European Space Agency (Esa) are developing their
own systems.

An advanced ability to monitor space debris, satellites,
near-Earth objects and solar activity is known as Space Situational
Awareness (SSA). Many experts see this as a step to space traffic
control.

Although there have been some near-misses and a few minor
collisions, this is the first time two intact satellites have
crashed into each other.

The latest incident has produced the worst field of space debris
since China destroyed a defunct Fengyun satellite with a missile in
January 2007.

That incident, designed to test an anti-satellite weapon system,
produced more than 2,000 separate fragments of debris.

On Christmas Eve, the US Air Force notified Esa that a European
weather satellite called Metop might be threatened by a piece of
debris from the Chinese A-Sat test.

Ultimately, no action was taken. But the event highlighted
Europe's near-total reliance on the US military for knowing what is
going on in space.

The International Space Station (ISS) flies at an altitude of
about 350km (220 miles), well below the point, some 790 km (490
miles) up, where the Russian and US satellites collided.

Nasa has said it considers the threat to the ISS to be low, but
that the orbiting outpost could carry out a collision avoidance
manoeuvre if necessary.

[email-masked]

Bookmark with:

Delicious

Digg

reddit

Facebook

StumbleUpon

What are
these?

E-mail this to a friend

Printable version

Print Sponsor

SEE ALSO

Russian
and US satellites collide
12 Feb
09 |  Science & Environment

RELATED INTERNET LINKS

Nasa

US Air Force Space
Command

The BBC is not responsible for the content of external
internet sites

TOP
SCIENCE & ENVIRONMENT STORIES

Russian
and US satellites collide

Obama
'must act now' on climate

Galapagos
damage 'must be curbed'

MOST
POPULAR STORIES NOW

E-MAILED

READ

WATCHED/LISTENED

Morrissey
scotches Smiths reunion

Millions
'opt for DIY dentistry'

Russian
and US satellites collide

Dutch
MP banned from entering UK

Nettles
to leave Midsomer Murders

Most
popular now, in detail

E-MAILED

READ

WATCHED/LISTENED

Russian
and US satellites collide

Striker
charged over sex attack

Pakistan
admits India attack link

Sat
collision highlights growing threat

India
pair found guilty of murder

Most
popular now, in detail

E-MAILED

READ

WATCHED/LISTENED

The US 'recession diet'

Satellite collision
reconstruction

Obama dines on famous fast
food

Koala 'Sam' rescued from
fires

Darwin's Galapagos under
threat

Most
popular now, in detail

FEATURES, VIEWS, ANALYSIS

Growing
threat

Space collisions highlight the need orbital
vigilance

Lincoln's
legacy

US celebrates Abraham Lincoln's bicentenary

FROM BBC SPORT
>>
2016
hopefuls

Guide to the four candidate cities

Skip to
top

PRODUCTS
& SERVICES

E-mail
news

Mobiles

Alerts

News
feeds

Podcasts

Explore the BBC

Home

Popular links

Being
Human

Doctor
Who

BBC
Archive

BBC links A to F

BBC
iPlayer

CBBC

CBeebies

Food

BBC links H to L

Health

History

Learning

Local &
Nations

BBC links M to Sc

Music

News

Radio

Science &
Nature

BBC links Sp to W

Sport

TV

Weather

A whole lot
more

To
top

Site Links

News Sources

About BBC News

BBC links

About the BBC

BBC Help

Contact Us

Accessibility
Help

Terms of Use

Jobs

Privacy
& Cookies

Advertise With Us

©
MMIX

The BBC is not responsible for the content of external
internet sites.

This page is best viewed in an up-to-date
web browser with style sheets (CSS) enabled. While you will be able to view the
content of this page in your current browser, you will not be able to get the
full visual experience. Please consider upgrading your browser software or
enabling style sheets (CSS) if you are able to do so.