Two UK pilots trying to break the world altitude record for a manned balloon flight will follow a special diet ahead of their attempt.
Colin Prescot and Andy Elson will be wearing fully pressurised flight suits when they soar more than 130,000 feet (40,000 metres) into the stratosphere with the 1,270-ft (387 m) tall QinetiQ 1 balloon.
A scale model of the balloon has been tested to destruction
But they will be unable to eat during the flight, and will carry just two-thirds of a litre of water each, accessed through tubes in their helmets.
So project sponsor QinetiQ has devised a strict diet to help them maintain energy levels and reduce bodily waste.
Three days before the launch Mr Prescot, 51, from Stockbridge, Hampshire, and Mr Elson, 48, from Wells, Somerset, will follow a low-residue high-carbohydrate diet, including white bread, white rice and pasta.
And in the final 24 hours before take-off, they will take on nutrient rich liquids.
The pair will also avoid alcohol in the run-up to the flight because it causes dehydration.
The balloon will be launched from the prototype trimaran warship Triton off St Ives, Cornwall, this summer when a 72-hour "weather window" appears.
Last year's planned launch was called off when the ideal weather failed to materialise.
The full-sized balloon, 400 times the size of ordinary passenger balloons when inflated, will be made of about nine acres of super-thin plastic.
Mr Prescot and Mr Elson will make their ascent on an open flight deck, carrying enough oxygen to last for 11 hours.