gary
02-09-2014, 05:20 PM
An article by Alexander Hellemans (http://spectrum.ieee.org/tech-talk/aerospace/satellites/two-galileo-satellites-are-parked-in-the-wrong-spots)posted on the 29 Aug 2014 on
the Institute of Electrical & Electronics Engineers (IEEE) Spectrum Magazine
web site highlights an error made in placing two Galileo satellites
into their correct orbits.
Galileo is Europe's Global Navigation Satellite System (GNSS), their answer
to the ubiquitous American GPS GNSS.
On August 22nd a Soyuz rocket took off from French Guiana carrying the
fifth and sixth satellites of the Galileo constellation.
However, the upper stage injected them into incorrect elliptical orbits
rather than the required circular orbits.
The positioning error was so great that it cannot be corrected by the
satellites hydrogen-fuelled positioning thrusters, which only have
a small amount of propellant designed for small corrections.
The satellites are now in orbits that make then unsuitable for use
as navigation satellites.
According to the Russian Space Agency, the problem was likely due
to a software error, apparently a weak point for the Russians due
to underfunding.
The Galileo project has already faced six years of delays and this most
recent failure may lead to additional delays.
Article here :-
http://spectrum.ieee.org/tech-talk/aerospace/satellites/two-galileo-satellites-are-parked-in-the-wrong-spots
the Institute of Electrical & Electronics Engineers (IEEE) Spectrum Magazine
web site highlights an error made in placing two Galileo satellites
into their correct orbits.
Galileo is Europe's Global Navigation Satellite System (GNSS), their answer
to the ubiquitous American GPS GNSS.
On August 22nd a Soyuz rocket took off from French Guiana carrying the
fifth and sixth satellites of the Galileo constellation.
However, the upper stage injected them into incorrect elliptical orbits
rather than the required circular orbits.
The positioning error was so great that it cannot be corrected by the
satellites hydrogen-fuelled positioning thrusters, which only have
a small amount of propellant designed for small corrections.
The satellites are now in orbits that make then unsuitable for use
as navigation satellites.
According to the Russian Space Agency, the problem was likely due
to a software error, apparently a weak point for the Russians due
to underfunding.
The Galileo project has already faced six years of delays and this most
recent failure may lead to additional delays.
Article here :-
http://spectrum.ieee.org/tech-talk/aerospace/satellites/two-galileo-satellites-are-parked-in-the-wrong-spots