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British Antarctic Survey [Printer-friendly version]
August 14, 2006

US SATELLITE PROTECTION SCHEME COULD AFFECT GLOBAL COMMUNICATIONS

A proposed US system to protect satellites from solar storms or high-
altitude nuclear detonations could cause side-effects that lead to
radio communication blackouts, according to new research. If
activated, the "radiation belt remediation" (RBR) system could
significantly alter the upper atmosphere, seriously disrupting high
frequency (HF) radio wave transmissions and GPS navigation around the
world.

The remediation system aims to protect hundreds of low earth-orbiting
satellites from having their onboard electronics ruined by charged
particles in unusually intense Van Allen radiation belts "pumped up"
by high-altitude nuclear explosions or powerful solar storms.

The approach, which is being pursued by the US Air Force and the US
Defense Advanced Research Projects Agency, involves the generation of
very low frequency radio waves to flush particles from the radiation
belts and dump them into the upper atmosphere over one or several
days.

The scientific team from New Zealand, UK and Finland calculate that
Earth's upper atmosphere could be dramatically affected by such a
system, causing unusually intense HF blackouts around most of the
world.

Dr Mark Clilverd from British Antarctic Survey says, "Some planes and
ships that rely on HF communications could lose radio contact, and
some remote communities that also depend on HF could be isolated for
as long as six to seven days, depending on the system's design and how
it was operated. GPS signals between ground users and satellites would
also be disrupted as they pass through the disturbed ionosphere."

The disruptions result from a deluge of dumped charged particles
temporarily changing the ionosphere from a "mirror" that bounces high
frequency radio waves around the planet to a "sponge " that soaks them
up.

The research is published in the August edition of the international
journal Annales Geophysicae. The researchers suggest that policymakers
need to carefully consider the implications of remediation.

If the intense radiation belts resulted from a rogue state detonating
a nuclear-tipped missile in the upper atmosphere, using such
remediation technology would probably be acceptable to the
international community, regardless of any side effects. However,
using the system to mitigate the lesser risk to satellites from
charged particles injected by naturally occurring solar storms should
be considered more closely. The impact of the disruption to global
communications needs to be weighed carefully against the potential
gains.

Ends

Issued by British Antarctic Survey Press Office on behalf of BAS,
University of Otago in New Zealand, Sodankyl� Geophysical Observatory
in Finland and the Finnish Meteorological Institute.

Media enquiries to BAS Press Office. Athena Dinar -- tel: +44 1223
221414, mob: 07740 822229, email: a.dinar@bas.ac.uk

The atmospheric implications of radiation belt remediation by Craig J
Rodger, Mark A Clilverd, Thomas Ulich, Pekka T Verronen, Esa Turunen,
Neil R Thomson is published in the August issue of Annales
Geophysicae. http://www.egu-edia.net/content/view/99/47/

Dr Craig Rodger, University of Otago, New Zealand -- tel: ++64 3 479
4120, email: crodger@physics.otago.ac.nz

Dr Mark Clilverd, British Antarctic Survey -- tel: +44 1223 221541,
email: m.clilverd@bas.ac.uk

Notes for Editors

It has been suggested that a nuclear airburst at high altitude would
significantly shorten the operational lifetime of low earth-orbiting
satellites. Even a "small" detonation (Precautionary Principle10-20 kilotons) occurring at
altitudes of 125-300 km, could lead to the loss of 90% of all low
earth orbit satellites within a month. In 2004 there were
approximately 250 satellites operating in low earth orbit (LEO). These
satellites perform many roles, including communications, navigation,
meteorology, military and science. In the event of a nuclear airburst
at high altitude, or an unusually intense natural injection, this
large population of valuable satellites would be threatened. Due to
the lifetime of the injected electrons, the manned space programme
would need to be placed on hold for a year or more.

The radiation belts were discovered by James A. Van Allen on Jan. 31,
1958, the first major scientific discovery of the early space age. He
died last week (9 August) in Iowa City, at the age of 91. A Geiger
counter on board the Explorer 1 satellite, developed by Dr. Van Allen,
recorded two belts of charged particles trapped by Earth's magnetic
field. One belt is 400 to 4,000 miles above the surface, and the other
is 9,000 to 15,000 miles high, both curving toward the magnetic poles.
The Van Allen Belts remain a crucial area of study in space science,
as evidenced by a recently announced, $100 million NASA project to
study the effect of the belts on satellite communications and global
navigation systems.

In the earliest days of the Space Age, the US "Starfish Prime" HANE, a
1.4 megaton detonation that occurred at 400 km above Johnston Island
in the central Pacific Ocean on 9 July 1962, damaged 3 of the 5
satellites operating in space at the time. This included the world's
first active communications satellite, Telstar, which failed due to
radiation exposure, even though the satellite was launched after the
Starfish Prime explosion. The detonation also caused an
electromagnetic pulse that shut down communications and electrical
supply in Hawaii, over 1300 km away.

HF radio frequencies are very important because of their wide uses.
Many developed countries use HF for radio communications to and from
aircraft and ships, international broadcasting, amateur operations,
and for fixed long-distance radio communications. Some countries still
find HF cost-effective for their domestic radio communications needs,
such as national broadcasting, mobile, and fixed point-to-point
communications.

The Global Positioning System, usually called GPS, is the only fully
functional satellite navigation system. A constellation of more than
24 GPS satellites broadcast precise timing, using 1.2-1.5 GHzradio
signals, to GPS receivers, allowing them to accurately determine their
location (longitude, latitude, and altitude) in any weather, day or
night, anywhere on Earth. GPS has become a vital global utility,
indispensable for modern navigation on land, sea, and air around the
world, as well as an important tool for map-making and land surveying.
GPS also provides an extremely precise time reference, required for
telecommunications and some scientific research. The operation of an
RBR system could lead to serious GPS degradation at mid latitudes, a
new and unexpected experience for mid-latitude GPS users.

British Antarctic Survey is a world leader in research into global
issues in an Antarctic context. It is the UK's national operator and
is a component of the Natural Environment Research Council. It has an
annual budget of around &pound;40 million, runs nine research programmes and
operates five research stations, two Royal Research Ships and five
aircraft in and around Antarctica. More information about the work of
the Survey can be found at: www.antarctica.ac.uk

The University of Otago is New Zealand's oldest university. Located in
Dunedin, Otago is the southern-most University of the country, with
more than 17,800 students and 3300 staff. In New Zealand, universities
are institutions where teaching is primarily undertaken by those
engaged in research and scholarship. As New Zealand's oldest
university, Otago has a long established tradition of research
excellence. Since its foundation in 1869, the University has steadily
increased its teaching and research activities, while building on its
original strengths, including Physics. More information on the
University of Otago can be found at: www.otago.ac.nz.

The Sodankyl� Geophysical Observatory is an independent research
department of the University of Oulu, located in Lapland, and
established in 1913 by Finnish Academy of Science and Letters to
perform geophysical measurements and research based on the observation
results. More information on Sodankyl� Geophysical Observatory can be
found at: www.sgo.fi.

The Finnish Meteorological Institute is the agency responsible for
gathering and reporting weather data and forecasts in Finland. The
Institute is an impartial research and service organisation with
expertise covering a wide range of atmospheric science activities
other than gathering and reporting weather data and forecasts. The
main research subject of the Finnish Meteorological Institute is the
Earth's atmosphere. Other research topics include the study of near
space and solar influence on the planet's atmospheres. More
information on the Finnish Meteorological Institute can be found at:
www.fmi.fi