Just how hard can it be to fly round the world in a balloon?
Cable and Wireless pilots Andy Elson and Colin Prescot have smashed the endurance record, but with their heater breaking down and a daring sky-walk at 20,000ft it has not all been plain sailing.
BBC News Online put your questions to them - and here are their answers:
Q. At what point during the landing sequence is the balloon detached from the capsule?
John Charman, London, UK
A. During calm conditions the balloon actually stays attached to the capsule on landing. If the conditions are rough we can release the balloon at the point we feel is necessary for our safety.
Q. What has been the most memorable sight of your journey so far?
Andy Bullifent, Saalisbury UK
A. The dunes in the North Sahara desert were stunning. They looked exactly like waves.
Q. How do you arrange sleeping and eating in such cramped spaces?
Peter Durnford, Vancouver, Canada
A. We work 7 hours on duty, 7 hours asleep and the remainder of the day we are both up and working together. We have a kettle, which we use to heat dehydrated food.
Q. What contingency plans do you have should you be challenged or even attacked if you fly over a country less than hospitable at your flying over it's airspace? How well in communication are you with appropriate foreign ministries or their representatives on this matter of national airspace?
A. Flight plans are filed by Mission Control 12 hours before entering any country's airspace. All countries on the projected route have given us clearance. The flight plan is to confirm our exact track.
Q. Time and time again, we hear of people trying to break such a record as the ones you two are presently attempting. On one hand, it can be said that it is a test of human spirit and endurance to break such records, but on the other hand it is also a very expensive operation. Is it morally rith to attempt such expensive operations when there is so many people living in poverty. I am sure, that if your attempt in breaking the world record is successful, many magazines and TV would like to interview you. I hope money raised from such appearances will be used for charitable purposes perhaps in the countries that you are crossing over. I wish you both good luck in your attempt.
Kanshukan Rajaratnam, Cape Town, South Africa
A. Thank you for your message of good luck, it means a lot to us both that people back home are sending us these wishes. Please be aware that if we are successful in achieving this round the world attempt, $500,000 of our prize money will be going to charity.
Q. Why do you think the past few years have seen such a resurgence of round-the-world ballooning attempts? Has the technology improved dramatically in recent years?
Chris Perine, Washington, USA
A. Computer assisted design technology has helped make balloons bigger and safer. We can be more accurate with fuel and weight calculations, which affect endurance. The main advance has been in weather forecasting systems particularly at high altitude where you get the most speed.
Q. What sort of messages of encouragement do you receive from passing airliners and ground control staff? From us in Indonesia keep well and make it a first for Britain.
Nigel Piper, Jakarta, Indonesia
A. We are in touch with Ground Traffic Control of each country at least 12 hours before we enter their airspace. They are always very encouraging and inform us of other air traffic.
Q. What will your next challenge be when you have been successful with this one?
Gerard Allen, Marden, Kent, UK
A. The edge of space: 133,000ft under a gas balloon wearing spacesuits like Russian astronauts on an open gondola.
Q. How do you get a resupply of food, or is there enough on there for your entire journey no matter how long it will take?
Sanjeev C. Patel, Fairfax, VA, USA
A. We have enough food for one month - our projected length of time in the air is 21 days.
Q. What convinces you that you can succeed where others have failed? And how much of this journey comes down to luck?
David Locking, Houston, Texas, USA
A. We think we can succeed because of a number of reasons. Firstly we have a much bigger balloon envelope than any other previous attempts - it is over 1 million cubic feet in size, which gives us additional endurance advantage. Other advantages of the Cable & Wireless balloon is that it can carry more fuel than previous balloons, which means it can stay in the air for longer. I have (AE) have devised a way in which kerosene can be burnt at altitude and not freeze at -90 degrees centigrade. Because we can fly at a higher altitude, it means we can fly above adverse weather systems that have halted other round the world balloon attempts so far. The other advantage of using kerosene is that unlike propane it does not have to be stored under pressure but purely in liquid form. On this flight we are carrying our fuel in heavy duty plastic bags which when empty are much lighter than the cylinders used to store propane under pressure.
Q. How do you dispose of waste? Store it until your return - or jettison it?
Brian Foster, Stanford in the Vale, UK
A. We have a conventional airline lavatory on board - all non biodegradable waste is compressed and stored in the keel.
Q. Do you feel that the Chinese ban is a part of security paranoia or flexing political muscles against British crew? Do you spend a lot of time watching life underneath you? Wish you to make it despite all the artificial hurdles.
Jaroslav Ispolatov, Ithaca, USA
A. In answer to your first question we think it is a combination of both. However, we are not the sort of people who stop driving to Newcastle just because Junction 19 of the M1 is closed. We have been at c.24,000ft so won't see much until we come lower over India.
Q. What is the view like?
Jackie Winthorpe, Newcastle, UK
A. At the moment we are travelling at an altitude of 24,00ft so we can't see much, but once we come lower over India hopefully the view will be more interesting. When we were over the Sahara desert the dunes were stunning - they looked just like giant waves.
Q. What do your families think about you doing this? Do they think you're completely mad? Do you think you are completely mad? Good Luck!
Matthew Winnington, Liverpool, UK
A. Thank you for your message of good luck. Both of our families are very much used to us doing things like this. We are both naturally adventurous people and are always undertaking exciting challenges like this - not mad, just adventurous!
Q. Can you hear the wind in the gondola or are you gliding silently despite the speed?
Ben Dash, Swindon UK/Dallas, USA
A. There is no wind noise inside here. We are not really aware of the movement as we are moving with the winds.
Q. Just to wish you boys all the best with the flight and that you make it around the world┐.Everyone at Cardiff University here are rooting for your both┐Oh yes, what do you think you are most looking forward to when you land? What is the most spectacular sight you have or hope to see whilst up there?
Iain Price, Wales
A. Thank your for your wishes of good luck - it means a lot that everyone at home is rooting for us. Some of the things we miss the most, are plates - we hate eating out of mugs; a sponge - for obvious reasons; and of course our families. So far the best view was over the Sahara desert where the sand dunes looked like huge waves.
Q. Just how good would it be to beat Branson to this record?
Ali Towers, Edinburgh, UK
A. Obviously we are very positive that we can make it around the world - and we believe that we have a better chance than any one else - for more than one reason. Basically we have a bigger balloon than any other attempts, we are using kerosene instead of propane which does not have to be kept in pressurised containers. We are carrying our fuel in heavy duty plastic bags which when empty are much lighter than the cylinders used to store propane under pressure - so we are carrying a lot more fuel than previous balloon which gives us the ability to manoeuvre round adverse weather patterns. Both of us will be ecstatic if we can make this around the world record.
Q. What, if any, bird life is evident on your flight path?
Kenny Murray, Scotland
A. At the moment we are travelling at an altitude of 24,000ft in a sealed capsule - so there is not a lot we can see out of the window. But we will be able to see more when we lower the capsule over India.
Q. On your non-stop journey have you spotted any places you would like to return to, and check out at ground level?
J Hampson, UK
A. For most our flight we have been over the desert. We have not seen a house, street or even a camel in all the time! We are looking forward to some varying views over the next few days as we lower the balloon over India. Sometimes the views from the balloon can be stunning. On the around the world attempt I (AE) made last year, we got a birds eye view of the Taj Mahal - truly amazing. Hopefully, we should get some equally majestic views this time."