New York's John F Kennedy International airport was the scene of an improbable aviation milestone, as the Swiss technology demonstration project Solar Impulse touched down at a few minutes past 11pm on 6 July after an 18h 23min flight from Washington DC to complete a five-legged coast-to-coast mission without burning a drop of fuel.
The solar-powered single seater - with the wingspan of an A320 but the mass of a Volkswagen Golf, about 1,400kg (3,080lb) - exploits exotic materials and assembly techniques to squeeze every gram of efficiency out of its structure and electric power management.
Solar Impulse on arrival at New York's John F Kennedy International airport
The pilot - project co-founder André Borschberg for the DC-NYC leg, but just as often his Solar Impulse partner Bertrand Piccard - must also operate at the limits of physical capability in a tiny cockpit with the barest of creature comforts; diet, exercise, sleep management and even self-hypnosis and micro-napping techniques are being honed to allow them to endure marathon sessions at the controls.
The aircraft, which charges its batteries in daylight hours and runs off stored power at night, is understood to have landed with more power onboard than at take-off on most of the US flight legs.
Borschberg and Piccard had already achieved flight for 24h using solar power only, and crossed continents with an eight-leg, 6,000km (3,240nm) round trip from home base in Payerne, near Geneva, to Rabat in Morocco.
Their next big goal is a round-the-world flight, possibly in 2015, in a second iteration aircraft that is under construction.
Solar Impulse cruises at 30,000ft (9,150m), and the complete 5,650km trip from San Francisco's Moffet Field took 105h 41min at an average speed of 28.8kt (53.3km/h).
However, flying such a delicate aircraft demands careful routing to accommodate the weather, and the final leg was actually cut short by 3h owing to a tear in the fabric on the lower side of the left wing.
"This last leg was especially difficult due to the damage of the fabric on the left wing," says Borschberg. "It obliged the team to envisage all the possible scenarios, including bailing out over the Atlantic.
"But this type of problem is inherent to every experimental endeavour. In the end, this didn't prevent us from succeeding in our Across America mission and provided an invaluable learning experience in preparation for the round-the-world tour in 2015."
Borschberg and Piccard are keen to stress that Solar Impulse is not so much an aviation project as an energy project. The pair are hoping that by demonstrating what can be achieved in the air with so little power, people on the ground will recognise that a new age of environmentally sustainable living is within their grasp.
As Piccard told Flightglobal in autumn 2012 during early-stage preparations for the transAmerica flight, the real goal of Solar Impulse "is to create positive emotions around new technologies".