by G S Mudur Mar

New Delhi: India's space agency two months ago launched four tiny American satellites that had been denied permission to fly into space by US regulators because they are too small to be tracked by America's space surveillance network.

The Indian Space Research Organisation's Polar Satellite Launch Vehicle (PSLV) had ferried into space four 10-cm-sized satellites - Spacebee 1, 2, 3 and 4 - on January 12 under a commercial pact with Swarm Technologies, a US start-up.

But the US Federal Communications Commission (FCC) had on December 12, 2017, denied Swarm Technologies authorisation to launch the four spacecraft because the US Space Surveillance Network would find it difficult to detect such small satellites. The network catalogues and tracks active and inactive satellites, satellite fragments and space debris that orbit the Earth.

"We cannot conclude that a grant of this application is in the public interest," the FCC had said in its letter to Swarm Technologies.

The letter noted that the company had proposed "to deploy and operate 4 spacecraft that are smaller than 10cm in one of their three dimensions." The spacecraft are "therefore below the size threshold at which detection by the Space Surveillance Network can be considered routine".

However, Antrix, ISRO's commercial wing, launched the Spacebee satellites on the January 12 PSLV flight that also carried ISRO's 710kg Cartosat-2, an Earth-mapping satellite, and 24 other foreign satellites from customers in Canada, Finland, France, South Korea, the UK and the US.