Weak solar cycle may keep more space junk in orbit

London, June 28 : A new computer simulation has suggested that a weak and under-active solar cycle could keep thousands of pieces of the destroyed Chinese satellite Fengyun-1C in orbit for far longer than anticipated.

That could mean more damage to orbiting satellites in the coming years.

According to a report in New Scientist, though solar storms are generally bad for satellite electronics, severe solar weather helps to clears out small objects in low-Earth orbit by heating up the diffuse atmosphere there. he hotter, thicker gas pulls on debris, causing it to fall into and break up in the Earth's atmosphere.

"The more flux comes out of the Sun, the faster those pieces will decay back to Earth and get out of the way of other satellites," said research engineer David Whitlock of the NASA Orbital Debris Program Office at the Johnson Space Center in Houston, Texas, US.

"If it's a low solar cycle, the pieces will be up there for much longer," he added.

Though researchers are divided over just how active the coming solar cycle, expected to peak around 2012, will be, some say it will be relatively tranquil.

This could keep more space junk in orbit, including thousands of pieces of the Chinese satellite Fengyun-1C that were created in 2007 when the craft was shot down by China in an anti-satellite weapon test.

More than 2300 pieces of the satellite larger than 10 centimeters across have been catalogued, and roughly 400 more are being tracked by the US Space Surveillance Network.

These numbers are set to fall, regardless of the severity of the solar cycle, as the pieces gradually get dragged into Earth's atmosphere, where they will burn up.

But, if the weak solar cycle forecast is correct, hundreds more pieces of Fengyun-1C debris larger than 10 cm will still be in orbit by 2019 compared to a normal cycle, according to simulations by Whitlock and colleagues.

This could spell trouble for satellite operators, who must plan manoeuvres to avoid passing Fengyun debris.

Mild solar weather could also keep thousands of smaller pieces in orbit.

"An estimated 40,000 Fengyun pieces between 1 and 10 cm across - below the limit ground-based radars can detect - currently circle the Earth," said Whitlock.

These objects can also cause considerable damage.

"Anything over 1 centimeter can really cause problems, almost for any satellite. If it happens to hit an instrument or an antenna, it could completely disable it," Whitlock told New Scientist.

ANI