PARIS — The 20-nation European Space Agency (ESA), in what may reflect the embarrassment it felt when its flagship environmental satellite died in orbit and became a debris threat that will last a century, has delayed the contract award for a next-generation polar-orbiting weather satellite system to assure that the spacecraft are built to disintegrate over the Pacific Ocean on retirement.
ESA Director-General Jean-Jacques Dordain said the three-month delay in the award for the three MetOp Second Generation satellites, mainly to integrate larger fuel tanks into the design, is a small price to pay for leaving popular orbits clean and reducing the threat of debris falling on populated areas.
MetOp-SG will succeed the current MetOp satellites in a polar orbit of about 800 kilometers in altitude. But the second-generation MetOp will feature three pairs of satellites in succession.
MetOp-SG is managed as a partnership between ESA and Europe’s weather satellite organization, Eumetsat, of Darmstadt, Germany.
ESA has agreed to spend about 800 million euros ($1.1 billion) on the design and construction of the first MetOp-SG models. Eumetsat has tentatively budgeted the program at 3.4 billion euros over more than 20 years, including operations of each successive pair of satellites.
Dordain said ESA has given the two competitors for the MetOp-SG prime contract, Thales Alenia Space and Astrium Satellites, until late November to submit their bids — three months later than originally planned — to incorporate the larger fuel tanks.
Speaking here Oct. 18 at a contract signing ceremony for the MetOp-SG’s Infrared Atmospheric Sounding Interferometer (IASI) instrument, Dordain said the MetOp-SG satellites will use twice as much fuel to power themselves into a controlled atmospheric re-entry than they will use in their 7.5-year operational lives.
Nonbinding international rules on orbital debris mitigation call for low-orbiting satellites to be retired in a position that allows them to be pulled into the atmosphere within 25 years of retirement.
But the rules also stipulate that these uncontrolled re-entries not be done with satellites whose size or configuration raises the risk that their pieces could survive re-entry and pose a danger to people or property.
The debris-mitigation guidelines say that if the risk of re-entry survival is more than 1 in 10,000 — as is the case with a 4,000-kilogram-class satellite like MetOp-SG — stronger measures should be taken.
NASA and the U.S. National Oceanic and Atmospheric Administration (NOAA) came to the same conclusion for their Suomi NPP meteorological satellite, which was launched in 2011.
Eumetsat Director-General Alain Ratier said here that the 800-kilometer polar orbit, used by the United States and Europe in a coordinated fashion to provide weather data, is of critical importance to weather forecasts.
“There are now two of us — Europe and the United States — that provide most of the data from this orbit,” Ratier said. “China will soon be added as a third partner to coordinate its use. This orbital region is too important not to take the necessary measures to keep it clean.”
ESA’s 8,000-kilogram, 8-meter-tall Envisat environment monitoring satellite, built before the orbital debris measures were adopted, failed suddenly in orbit in 2012 at about 768 kilometers in altitude. Because it is festooned with fragile observing instruments that could shatter on impact with even tiny pieces of debris, it is viewed as an especially dangerous addition to the orbital garbage pile.
Ratier and Dordain made their comments at the headquarters of the French space agency, CNES, which is providing to Eumetsat the second-generation IASI. CNES also provided the first-generation IASI on the three first-generation MetOp satellites, two of which are in orbit. The third is scheduled for launch in 2016.
Thales Alenia Space, which built the first-generation IASI, lost to Astrium Satellites in the competition to built the follow-on sensor. Astrium Satellites Chief Executive Eric Beranger said here that Astrium’s design costs substantially less than the first-generation instrument.
Eumetsat officials agreed that Astrium’s three IASI instruments, at 230 million euros in total, are less expensive, after adjusting for inflation, than the three instruments built a decade ago, which cost about 210 million euros in 1998.
ESA now expects to choose a prime contractor for MetOp-SG in early 2014. Ratier said Eumetsat’s member nations would be asked to evaluate the program’s total cost at their meeting in July.
He said an initial vote on the program would be taken then, with final approval expected at the end of the year, in time to begin the hardware construction phase of the satellite contract in 2015. The first launch, aboard a medium-lift Soyuz rocket or equivalent, is scheduled for 2021.
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