High and mighty

Qinetiq plans to launch the world’s largest-ever balloon into the stratosphere this summer. Helen Knight sets the scene.

It might not look much like a space launcher, but when the giant Qinetiq 1 balloon takes off from the Cornish coast later this summer, that is exactly what it will be aiming to become.

Qinetiq 1 hopes to break the world altitude record for a manned balloon by reaching the very edge of space, 25 miles (132,000ft) into the stratosphere. From July to September the launch team will be on 72-hour standby for the right weather conditions for the 12-hour flight.

At peak altitude the balloon’s two pilots will be able to see the curvature of the earth. To reach this height specialist firm Flying Pictures, supported by Qinetiq, has built the biggest manned balloon in history, around 400 times the size of a typical hot air craft. Balloons stop ascending at a height where their weight is equal to that of the air displaced, and there is so little air at over 100,000ft that Qinetiq 1 needs to be this large to give it sufficient lift. At its launch the balloon will be as tall as the Empire State Building, and when it reaches 132,000ft it will have a volume of more than 40 million cu ft.

Indeed, Qinetiq 1 is so large that special machinery had to be built just to make it, says Colin Prescot, co-pilot and managing director of Flying Pictures. ‘The conventional way of building large balloons is to have an enormously long building, so the fabric can be welded together in single lengths. But having a building of several hundred feet in the south of England for just one project was obviously neither practical nor affordable, so instead we built a special machine,’ he says.

This huge balloon-making machine includes vast drums that feed the fabric to each other and a computer-controlled welding machine. And as the balloon itself is made from very lightweight polyethylene, similar to the material used in freezer bags, a polarised light machine is also used to show up the tiniest flaw in the plastic as a glaring hole.

The unprecedented size of the balloon and the record-breaking height of the planned flight make the project an enormous challenge for Flying Pictures, and it will obviously be a great personal achievement for Prescot and co-pilot Andy Elson, who as Qinetiq 1 project director was also responsible for designing and building the craft. But what would interest a technology firm such as Qinetiq in what is effectively a glorified balloon ride, other than the obvious publicity it will attract?

The flight may seem nothing but a fanciful adventure, but it offers some genuine technological and commercial opportunities, says Prescot.

If the balloon reaches its target it will be occupying an area of the atmosphere about which there is a gap in our understanding, he says. ‘It has been nicknamed the Ignorosphere as we know so little about it. It is higher than Concorde flies, but not as far out as rockets and satellites are orbiting.’

While in the ‘Ignorosphere’, the balloon will use a special piece of equipment developed by Qinetiq to take cosmic radiation readings. The Cosmic Radiation Effects and Activation Monitor (CREAM) has already gathered data from Concorde and the space shuttle, and the balloon flight will give Qinetiq the opportunity to gain experimental data at these unexplored heights.

This information, hopes Qinetiq, could prove invaluable in future work to develop methods of commercial hypersonic travel. Interest in high-Mach propulsion systems capable of powering a passenger aircraft at around one mile per second, or 3,600mph, has grown considerably recently. NASA alone is now spending $130m (£88m) a year on hypersonic research, as part of the US’s new National Aerospace Initiative.

To reach these speeds the planes will fly at far higher altitudes than existing passenger aircraft. Qinetiq is undertaking a four-year programme to explore high-altitude travel, called the Short Hypersonic Flight Experiment. The company is developing aircraft capable of flying at Mach 6, at an altitude of 32km. A short experiment is planned for later this summer, where a high-velocity, high-flying small aircraft will be launched.

But if commercial hypersonic flight is to become a reality, more information is needed on the effects of solar radiation in these unknown regions of the earth’s atmosphere.

It is not just air travel that is likely to benefit from the lessons learnt on the balloon flight. In the past people have tended to pass quickly through the area on their way to higher altitudes, but there is now a genuine interest in exploiting the region commercially, says Dr Terry Gardiner, a Qinetiq project manager acting as liaison officer between the balloon’s technical team and the wider organisation. ‘This particular region of the earth’s atmosphere, where quite honestly there isn’t anything else going on, offers an interesting opportunity, and there are quite a few people looking at using it for communications and military purposes such as surveillance and intelligence gathering.’

Sending up the equivalent of a satellite – although one that is nowhere near as expensive to make, launch and maintain – for particular applications or extended periods of time could prove extremely useful, says Gardiner. ‘There could be great potential in sending up lighter-than-air vehicles, or high-altitude long-endurance aircraft, which are designed to loiter at those altitudes and provide a platform for communications and data gathering,’ he says.

Researchers are already looking into the idea, and balloon launching might provide a cost-effective method of getting the aircraft into the ‘Ignorosphere’ in the first place, says Gardiner. Indeed, the company will be trying out this possibility on the balloon flight itself, as a novel way of satisfying a request from Flying Pictures for a photograph of the balloon with the curvature of the earth in the background.

‘When Flying Pictures started talking to us originally about taking the picture, all sorts of harebrained schemes were proposed. But we are now working on a solar-powered aircraft, which should also help us with our other aims for the flight.’

The plane will be tethered to Qinetiq 1 during the launch and flight, then spiral above the balloon when it reaches its destination. From this position on-board cameras will take a still photograph and video footage of the balloon, with the earth behind.

‘Tethering the aircraft to the balloon will make controlling it less of a problem for the pilots. There is a class of model aircraft which flies on a tether tied to a post, and this will be very similar to it, just quite a bit larger.’

Taking this photograph alone will involve another record, that of the highest-ever flight by an unmanned aircraft. But the team will not be able to claim this record officially because the plane will not have arrived at its destination under its own steam.

But while records may be fine for pilots and adventurers, the company is hoping the real prize will be the valuable information and experience gained from the launch itself. If the flight proves successful, we could soon see balloons being used to launch a range of communications and surveillance satellites into this untapped area of the earth’s atmosphere.

Sidebar: Gone in a gondola

To combat the extreme conditions and lack of atmosphere in the balloon the pilots will make the ascent in spacesuits on an open flight deck, or gondola.

The deck, which is made of carbon fibre, was chosen for its strength and relatively light weight. The central spine of the flight platform is a sealed tube containing all the necessary electronics, including the communications equipment and life-support system controls. This tube will be sealed 24 hours before take-off to ensure it is leak-tight, and from then on the electronics will remain in a sea-level-like atmosphere throughout the entire flight.

As the balloon rises it will pass through a very low temperature zone, at 40,000-50,000ft, of -70°C. To prevent the pilots breathing in icy-cold gas, a system has been developed to take advantage of the excess heat produced by the electronics. The life-support system plumbing is passed through the sealed tube containing the electronics, to heat up the gas before it goes into the pilots’ pressurised suits. As well as heating the gas this also ensures the electronics are kept cool, says Qinetiq’s Dr Terry Gardiner. ‘It is a matter of thermal management.

Scientists within our space department, who are used to calculating the thermal performance of satellites, have modelled the flight platform including pilots to ensure they reach a thermal balance.’

The stability of the flight platform itself will also be an issue at these icy-cold temperatures, so Qinetiq put the gondola through a simulated temperature cycle, with stress sensors placed on board, to ensure the structure remained intact.

But it is not just cold the platform will face: it will also be subjected to radiation from the sun. So as part of the stress-testing programme the platform was also subjected to simulated solar radiation of 1.3kW/m2. On the flight itself the pilots will be given solar blinds to protect them from this radiation.

Sidebar: Dressed for the part

As the flight platform is an open deck the pilots will effectively be on the longest spacewalk in history, lasting between eight and 12 hours.

Engineers at Qinetiq routinely work with military pilots, and have been preparing Prescot and Elson for operating under these unusual conditions, says Qinetiq’s Dr Terry Gardiner.

As the pilots ascend the pressure will steadily decrease, until they reach 132,000ft where it will be just two millibars. And with the atmosphere becoming unbreathable at over 20,000ft, the pilots’ spacesuits and life-support systems will be vital.

‘What makes this different from most space flights is that they are going to be in a pressurised suit for longer than anybody has needed to be in one before,’ says Gardiner.

The suits were made by Zvezda of Moscow, which has produced all the suits for the Russian space programme since the 1950s.

The suits and life-support systems need to remain in full working order long enough to last through the two-hour preparation time, the 12-hour flight, the deflation of the balloon and journey back to earth, until the pilots are picked up from the Atlantic. Timing will be key, as there is only a finite amount of gas within the life-support systems, says Gardiner.

‘It is a partial rebreathing system with gas scrubbers that take out the carbon dioxide. Eventually the scrubbers will saturate, and the CO2 level will increase. So if they are delayed substantially beyond 12 hours, they are probably going to start to get a headache.’

Sidebar: Out of this world

From July, the Qinetiq 1 crew will be on 72-hour standby, ready to take off if favourable weather is forecast. They are waiting for a clear, perfectly still day; the Met Office is also monitoring wind and temperature conditions in the stratosphere.The balloon will be launched from a ship about 16km off the north Cornish coast rather than from land, to avoid local wind turbulence.

Preparations for the flight will begin at dawn. The first two hours will be spent inflating the balloon. Following lift-off, the ascent to 132,000ft should take five to six hours. Stratospheric winds will blow the craft westward.

Qinetiq 1 will remain at its maximum altitude for an hour while the pilots carry out experiments in the stratosphere. Once these are complete they will start their descent by opening a valve at the top of the balloon to release helium. If the balloon descends too quickly the pilots can release ballast from the gondola. The descent into the sea should take two hours.

The pilots will release the balloon at the moment of splashdown. Parachutes are included for emergencies but cannot be used above 20,000ft.The gondola is expected to land at about 48km/h, and a foam ‘crumple zone’ underneath will cushion the impact. The gondola is designed to be stable in the water and is fitted with flotation bags. The flight operations centre will have been continuously predicting the splashdown point, expected to be about 150km west of the launch site, and rescue teams should be there to meet them.

The two pilots have 40 years’ ballooning experience between them. In 1991, Elson piloted the world’s first hot air balloon over Mount Everest.