US defence officials are considering shooting down a rogue American spy satellite in order to prevent its top-secret technology falling into enemy hands, according to reports.

Aviation Week revealed yesterday that Pentagon sources had confirmed the sat shootdown plans, though it is not yet certain that the US will put them into effect.

The surveillance satellite in question was manufactured by arms behemoth Lockheed for the US National Reconnaissance Office, and failed to come online as intended after being launched. Its price is unknown, the purchase having been made using secret "black" funding, but such hardware can be extremely expensive.

The errant spacecraft is expected to start experiencing worsened braking effect from the upper reaches of the atmosphere shortly, within the next few weeks, which will cause it to plunge deeper and so descend to Earth. The exact trajectory and impact point is uncertain, as are the effects on the satellite itself. It might break up into small pieces and be more or less totally destroyed, or substantial parts might come down relatively intact.

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The Pentagon has been happy in past weeks for the media - previously including the Reg - to focus on safety concerns such as debris hitting populated areas. The satellite's unused hydrazine manoeuvring fuel - which would have been used to shift orbits and pass over different areas, had the platform actually worked - has also been mentioned extensively.

In fact, however, these concerns are relatively minor. Even if large chunks of satellite did come down in a densely-populated area, the disaster potential is quite small compared to humdrum events such as gales or motorway pileups.

Similarly, while hydrazine is indeed nasty stuff, the satellite's fuel tank poses no great danger. Even in the unlikely event of the tank reaching ground still full and then rupturing, the resulting toxic plume would not affect people further than 20 or 30 yards away.

Similarly, if the satellite were carrying a radioisotope power source (a pint-size nuclear generator, sometimes used on US spy sats and deep-space probes) - which is categorically denied in this case - the danger would not be massive. Several Russian nuclear-powered spy satellites crashed or reentered uncontrolled back in Cold War times, without noticeable effects.

This kind of concern would frankly not be sufficient to get the Pentagon thinking about drastic options such as orbital or upper-atmosphere strikes. Indeed, under some contingencies shooting at the satellite could actually break it up and spread potentially dangerous fragments over a wider area.

If, in fact, the satellite comes down in North America, as the Pentagon has publicly hinted it might, one may be sure that the US spy community will breathe a massive sigh of relief - much though they might not make that attitude public.

Full article here.