14 DAY TRIAL // After an amazingly-long mission that spanned over 16 years, the ERS-2 satellite operated by the European Space Agency (ESA) is currently being retired from active duty. Over the course of its lifetime, the spacecraft has aided planetary scientists develop Earth-monitoring techniques.
A large part of the measuring methods current satellites use were first tested and validated aboard this testbed spacecraft. This was a pioneering mission in every sense of the word, ESA officials say.
ERS-2 was the second European Remote Sensing satellite. The first of the series, dubbed ERS-1, launched back in 1991, while ERS-2 took to the skies in 1995. Since then, the latter has been conducting scientific studies of our planet.
With these two missions, ESA moved to the forefront of Earth observation, which was then a relatively young field of research. When they launched, the ERS satellites were all the rage in technology and orbital performances.
Both had an identical suite of instruments. The sole difference was the ozone-monitoring device that ERS-2 had added to its capabilities. Between themselves, the satellites provided ESA with 20 years-worth of continuous data.
ERS-1 lasted only until 2000, when an error caused it to shut down unexpectedly. Its twin is now being retired in order to avoid it meeting a similar end. ESA wants to move the satellite to a lower orbit, where the agency could prevent it from becoming dangerous space debris.
Mission controllers need to devise a series of careful maneuvers in order to lower ERS-2 to its final orbit. They also need to do this before the spacecraft runs out of fuel, as this would make any type of movements impossible,
Thus far, the satellite has traveled in excess of 3.8 billion kilometers around the Earth, completing more than 85,000 orbits. These statistics also indicate the great degree of risk associated with continuing to operate the instrument.
Orbital and flight dynamics experts based at the ESA European Space Operations Center (ESOC), in Germany, are responsible for planning the path that would take ERS-2 out of its orbit. The move is expected to take a couple of weeks.
Moving the satellite will be accomplished via a series of thruster burns, which are currently scheduled to begin on July 6. At this point, the spacecraft is about 800 kilometers above Earth's surface, and experts want to move it to an altitude of about 550 kilometers.
In less than 25 years, ERS-2's orbit will decay enough to allow for it to reenter Earth's atmosphere and be destroyed high in the air.