Safety concerns have, for now, grounded plans by the Republic of Singapore Air Force (RSAF) to fly a radar-equipped balloon that can spot hostile threats coming from as far as Malacca.
The 55m-long helium-filled military blimp, known as an aerostat, was supposed to be airborne early last year to watch over Singapore.
But its launch was delayed because the giant balloon's United States-based manufacturer TCOM has failed to meet the RSAF's safety and operational requirements, The Sunday Times has learnt.
The yet-to-be-delivered aerostat will likely be tethered to the ground inside a military camp in the western part of Singapore.
A Defence Ministry spokesman cited "delays in delivery" yesterday, saying: "It is still undergoing rigorous testing by the manufacturer to ensure it meets the RSAF's stringent operational requirements and high safety standards."
The blimp will be secured with high-strength winch lines and a tether "built to withstand strong winds and lightning strikes". Its radiation emissions will be "as safe as those of mobile phones" and its radars will be certified to the same standards required for mobile phones and microwave ovens.
"The RSAF will apply safety procedures that are in line with the regulations developed by the US Federal Aviation Authority," said the spokesman. The air force is working with the Civil Aviation Authority of Singapore to plan its safe operation in Singapore airspace.
If the launch goes ahead, Singapore will be the first South-east Asian country with such a balloon.
US military leaders use aerostats to protect Washington DC against airborne threats and spot insurgents in Afghanistan. But last October, one blimp broke free from its mooring in Maryland and flew 240km, disrupting civil aviation and damaging power lines.
Designed to operate round the clock, Singapore's blimp will hover at around 600m - more than twice the height of UOB Plaza One, Singapore's tallest building.
It can spot hostile threats from as far as 200km away, double the distance covered by ground radars. It can scan up to Malacca for straying light aircraft, for instance, and detect small boats coming in from Indonesia's Pekanbaru. Information will be shared with other security agencies, such as the coast guard.
Defence Minister Ng Eng Hen, who in October 2014 announced plans for its launch, called it the "protector in the sky" and said it would be cheaper than flying surveillance planes.
Associate Professor Ng Teng Yong of Nanyang Technological University's School of Mechanical and Aerospace Engineering said it is crucial for the RSAF to "get its own aerostat right... as a runaway blimp could possibly drift into Indonesian or Malaysian territory".