The U.S. Federal Communications Commission (FCC)
stepped into a years-long debate on orbital debris by ordering tough new
measures governing how satellites are disposed of by their owners.
Over the objections of several of the world’s largest
commercial satellite-fleet operators, the FCC ruled that all U.S.-licensed
satellites launched after March 18, 2002, will have to be placed into so-called
graveyard orbits between 200 and 300 kilometers above the geostationary arc,
where most commercial satellites operate.
The ruling, published June 21, will set a regulatory
standard that will be difficult for other nations to avoid.
“Up to now, orbital debris has been handled in
gentlemen’s-agreement fashion, with soft recommendations that were ignored,”
said Christophe Bonnal, a member of an international group that has been pushing
the United Nations to adopt debris-mitigation standards. “It is time that people
started pounding the table, and it was absolutely necessary that the FCC do
it.”
The FCC selected March 18, 2002, as the cutoff date
because that was when it notified satellite operators that it was considering
rules on the subject. An FCC license is an indispensable ticket for any
satellite operator proposing services in the United States.
Commercial as well as government satellite operators
have been saying for years that they share the concerns that increasing debris
both in low Earth orbit and along the geostationary arc 36,000 kilometers above
the equator is a problem that ultimately could shut down the space
industry.
Space industry pioneers including Arthur C. Clarke,
who first discovered the properties of the geostationary orbital position, have
warned that orbital debris is the single largest long-term threat to the
continued use of space for satellites, and especially for manned
missions.
The perils of fast-flying particles, even as small as
a coin, left over from spent rocket stages and satellites is the main reason the
U.S. space shuttle flies upside down and backwards once in orbit. In that
position, shuttle astronauts are best protected from orbital junk.
The FCC based its new rules on recommendations made
by the Inter-Agency Space Debris Coordinating Committee (IADC), which includes
members from 11 of the world’s biggest spacefaring nations.
The recommendations complement measures taken by most
launch-vehicle operators to assure that their rockets are as benign as possible
once in orbit. A large portion of the thousands of pieces of orbital junk
tracked by the U.S.-Canadian North American Aerospace Defense Command (NORAD) is
the result of exploding rocket upper stages.
The most striking of the FCC measures deals with
satellites operating in geostationary orbit. Even some of the largest, most
profitable satellite-fleet operators have a checkered performance in moving
their spent spacecraft well out of the operating lane.
According to figures prepared for the IADC based on
NORAD data, of 13 geostationary satellites retired in 2002, only five were moved
to safe graveyard orbits. The other eight were placed into orbits that sooner or
later will threaten to disrupt operations in the geostationary arc.
The situation did not improve much in 2003, when just
six of 15 geostationary satellites taken out of service were placed in safe
orbits. One of the 15, Loral Space and Communications’ Telstar 4, abruptly
failed in orbit and could not be moved.
Eight others — Telesat Canada’s Anik C1, the Intelsat
5A, the Eutelsat 2 F1, the PanAmSat Galaxy 6, the Hispasat 1A, the German DFS
Kopernikus 3, Russia’s Gals 2 and India’s Insat 2C — were relocated to orbital
positions that are insufficiently out of the way, according to a summary
submitted to the IADC’s April meeting in Albano Terme, Italy, by Europe’s Esoc
space operations center in Darmstadt, Germany.
Under the new FCC rules, operators of geostationary
satellites will have to commit to raising their satellites to between 200 and
300 kilometers above geostationary orbit as a condition of receiving a license
to provide services in the United States.
The exact minimum post-retirement altitude will
depend on the satellite’s size and other factors that determine how likely it is
to drift back into the geostationary arc. The FCC estimates that for a standard
Boeing Satellite Systems 601-class satellite weighing 2,477 kilograms without
its fuel, the owner will need to raise the orbit by 266 kilometers.
In its ruling, the FCC says it considered making the
new rule retroactive to all FCC-licensed satellites in orbit. But several
satellite operators, including PanAmSat Corp. of Wilton, Conn., EchoStar
Communications Corp. of Littleton, Colo., SES Americom of Princeton, N.J., and
Inmarsat Ltd. of London said such a move would cost them huge amounts of
money.
That led to the compromise date of March 18, 2002,
which the FCC says will reduce “the potentially significant financial impact of
this new requirement.”
For a commercial satellite operator, a satellite in
stable position nearing the end of its life is in most cases generating revenues
that go straight to the bottom line. Some of this revenue will now be conceded
as operators reserve several kilograms of on-board fuel to assure their ability
to raise the satellite into the FCC-specified graveyard orbit.
Current monitoring technology makes it difficult for
operators to assess how much fuel is left in a satellite nearing retirement. In
at least one case in 2003, a satellite operator intending to follow the IADC
guidelines misjudged the fuel remaining and had to leave the spacecraft in a
less-favorable orbit.
“Operators are going to have to err on the side of
caution,” said Bonnal, who is the outgoing chairman of the IADC
debris-mitigation working group. “If they need 4 kilograms to raise the orbit,
they are going to have to save maybe 6 kilograms to be sure.”
Six kilograms of fuel is enough for between two and
three months of satellite operations.