By Jonathan Amos
Science reporter, BBC News
A proposal for the UK to join the International Space Station (ISS) project has been put forward by a group of scientists and engineers.
Their idea is for Britain to build and launch two modules that greatly enhance living conditions on the platform.
The Habitation Extension Modules would increase meeting and bunk space; and allow the UK to fly some dedicated science experiments.
The proposal is being supported by the British Interplanetary Society.
Details of the suggested programme are carried in the society's Spaceflight magazine.
The group argues that it would fire the public's imagination and give UK industry a wonderful new investment opportunity.
"This is a contribution to the debate on how the UK can get involved in human spaceflight," said Mark Hempsell, of Bristol University's aerospace engineering department.
"It would allow UK scientists to use the space station for experiments, pave the way for British astronauts, and bring significant development and investment to the country's industry," he said.
UK industry is locked out of human spaceflight projects
And, critically, commented Clive Simpson, the editor of Spaceflight, it would help bring on the next generation of scientists and engineers.
"The government says it's worried that fewer and fewer students are taking science and engineering courses, but this is a proven way of increasing that uptake," he told BBC News.
The British contribution would comprise two cylindrical modules that would attach to Node Three on the platform. Each Habitation Extension Module (HEM) would be just under six metres long and four metres wide.
One HEM would be fitted out as the common room. It would be arranged as a single room large enough to comfortably contain 10 people around a table. It is envisaged that this would be the location for teleconferences with Earth, be used for crew meetings and, of course, for crew entertainment.
The other HEM is essentially a dormitory with extra radiation shielding to protect astronauts while they sleep. This module would have six bunk spaces. Each cubicle would be three cubic metres in size.
UK HABITATION MODULES
HEM is a 3.8m x 5.7m cylinder; Modules add 100 cu m to ISS
HEM-C is a communal area for eating, meeting and socialising
HEM-D sleeps 6 astronauts with enhanced radiation protection
Launch on Soyuz-Fregat vehicle with 3 tonnes of supplies
Room for one ISS Payload Rack for UK experiments
Launch/build cost: £530 million; other costs about £70m
"There are sleeping provisions elsewhere on the station but they are crammed in little nooks and crannies," explained Mr Hempsell.
The rationale behind the proposal is to provide components that enhance the station. What is specifically not required, says the group, is another laboratory. The station will be well served by the Destiny, Columbus and Kibo modules when they are all in place.
However, the decision of the US to abandon its own habitation module means the living experience on the platform has been greatly compromised - and this would provide the proper opening for a British contribution.
"If you speak to the international partners, what they want is not more laboratories; what they want is something that will increase astronaut time on the station so that they can better use the labs they've got," said Mark Hempsell.
Expertise gained on the ISS would position the UK for the future
The issue, as ever, with the UK and space is cost. The group calculates the programme would amount to some £600m spread over six or seven years (until 2015).
In other words, each year would be equal to a little under half of the UK's current annual civil spend on space. And with a number of space/astronomy projects already facing cut-backs, many will argue that any extra funding should be spent covering the shortfall.
This latter point was emphasised by Leicester University astrophysicist Duncan Law-Green, who believes the UK is well placed to exploit the new private ventures opening up in human spaceflight.
He commented: "The UK should be investing in technology which will reduce the high cost of reaching space and working there - such as the new generation of commercial space stations, or projects like SABRE, a radical British design of air-breathing rocket engine which would make fully reusable spaceplanes a reality.
"Bolting an astronauts' lounge onto the ISS is not new, and it's not technically innovative - frankly it's throwing good money after bad."
At present, British government policy specifically bars any public programmes connected with human spaceflight, and it has directed that any monies instead go towards the robotic exploration of space - for example in Earth observation and unmanned planetary probes.
This means that although the country is a member of the European Space Agency (Esa; an ISS partner), the UK has elected to withdraw from all platform activities.
The consequences of this policy are that UK citizens are prohibited from becoming Esa astronauts and British industry is also locked out of the multi-billion-euro contracts to design and build components for the ISS.
A number of reports recently have described this position as a failed policy which has damaged both British science and industry.
The Royal Astronomical Society, the House of Commons Science and Technology Committee, and the government-commissioned Science and Exploration Working Group have all urged Whitehall to engage with human spaceflight.
One idea recently floated was that the UK could signal its desire to get involved with the ISS partners by purchasing one of the Russian "space tourist" tickets for a UK astronaut.
But Clive Simpson said such a minimal contribution would have limited return.
"Sending a 'space tourist' would be good for publicity but in terms of science and real work in engineering and industry, it wouldn't be that beneficial," he told BBC News.
"The modules, on the other hand, are a very practical proposal which would be of huge benefit to the astronauts onboard; and actually would feature in many everyday stories about the space station because they are where a lot of the media activity would occur."
The UK government recognises it needs a new space policy and has made noises in recent months that it may consider reversing its objection to human spaceflight. It is promising to come forward with a new strategy in the coming weeks.
The fear of some in the UK's space and aeronautics communities is that continued abstinence will make it harder for UK scientists and engineers to be a part of the next era in space exploration - the push to go back to the lunar surface and possibly on to Mars.