London, Feb 16 : Pentagon's decision to destroy a disabled US spy satellite can lead to disaster for the International Space Station (ISS), which would be struck by hundreds of thousands of marble-sized debris once the satellite is shot down.
According to a report in New Scientist, the Pentagon has cited concern about contamination from toxic hydrazine fuel as the main reason behind the decision to shoot down the satellite rather than let it disintegrate in the atmosphere.
The current plan for shooting down the US National Reconnaissance Office (NRO) satellite involves firing a modified navy missile at the spacecraft while it is about 240 km (150 miles) above the Earth.
The atmosphere is thick enough at that relatively low altitude that most of the debris will be dragged down and disintegrate in a matter of hours or days.
But, according to David Wright, co-director of the global security programme at the Union of Concerned Scientists in Cambridge, Massachusetts, US, some of the debris from the explosion could get kicked up to a higher orbit, where it could pose a threat to the ISS, which orbits the Earth at about 340 km (211 miles).
"It sounds to me like a bad idea," Wright told New Scientist. "This satellite is about two-and-a-half times as massive as the Chinese satellite destroyed last year, so you would expect to get a lot more debris," he explained.
According to Donald Kessler, a retired manager of NASA's Orbital Debris Office at Johnson Space Center, though the resulting debris from the explosion will be a cause of worry, the possibility of contamination from hydrazine is worse.
"When you're dealing with a chemical like that, it's a different ball game," Kessler told New Scientist.
But Max Meerman, a satellite engineer at the MDA Corporation in Vancouver, Canada, believes that concerns about debris are overblown.
"The satellite will be slowed down when it flies into the missile, so most bits from the impact will slow down, rather than speed up, and re-enter Earth's atmosphere even quicker," he said.