SWAPPING number-crunching as an accountant for donning an astronaut's spacesuit has to be one of the more unusual career changes.
But it is one step closer for the only Scot to have been shortlisted for the spaceflight project which aims to establish a human settlement on Mars of just 20 people by 2025.
The Mars One mission attracted more than 200,000 applications from hopefuls willing to leave on a one-way ticket to live in the inhospitable landscape of the Red Planet, where the average temperature is around minus 60C and the atmosphere has so little oxygen it cannot be breathed.
The private spaceflight project is led by Dutch entrepreneur Bas Lansdorp.
Now the candidates have been whittled down to 705 — with just one Scot making it through to the next round, which will involve an interview by a selection committee later this year.
In her video application, Sarah Johnson, 30, from Inverness, who is currently living in Abu Dhabi in the United Arab Emirates, joked: "The reason I want to go on the mission to Mars is I find myself waking up every morning thinking there must be more to life and the reason for that is probably because I am an accountant.
"However, I want to dispel the myth that accountants are dull and boring by becoming the world's first astronaut accountant."
Johnson said she has volunteered in Tanzania, Costa Rica and India and travelled extensively in countries "out of her comfort zone", including Uganda, Kenya, Cambodia and Laos.
She added: "I think the skills I have gained as an accountant have prepared me well for this mission —for example, I work with people from a wide range of cultural backgrounds and I am meeting new businesses every day from a diverse range of sectors and helping understand their problems and solve those problems."
The candidates — who don't necessarily have any experience of flying or science — were selected from the original pool of 200,000 applications in December 2013.
Candidatess were asked to provide a medical statement of health and make their application available to the public.
The remaining 418 men and 287 women will now be invited for a personal interview, after which teams of prospective Mars settlers will be selected to dedicate eight years of their lives to preparing full-time for the mission.
The aim is for the first crew of four to depart in 2024.
Professor Richard Brown, director of the Centre for Future Air-Space Transportation Technology at Strathclyde University, said it was an interesting programme but pointed out the timescale for achieving the mission was "very short".
He said: "There are a number of technological problems, not withstanding all the ones about how people live once you have got them there.
"There are also very substantial problems to do with how you actually get them there in the first place — it is certainly not a trivial matter to get even 20 people from the Earth to Mars using the kind of technologies we have available today.
"It is a huge technological challenge just in terms of the scale and technology - for example, if you look at the various Rover (robotic) missions that have been to Mars, they have all been very lightweight compared to what would have to be taken down onto the surface of Mars to support human existence there."
According to Mars One, the cost for putting the first four people on Mars will be around $6 billion (£3.6 billion), with further manned missions costing around $4bn (£2.3bn) each.
The project is a private initiative, which intends to raise the necessary funds through means such as sponsorships, crowdfunding and selling broadcasting rights for a "Big Brother"-style event which will see the preparations and landing on Mars being broadcast around the world.
Brown said: "It is perhaps quite an open question to know whether it will be a successful endeavour or not — but one very interesting thing about it is the change in mentality from the early days of space travel.
"Then, space travel was seen as the preserve of governments and governmental organisations which had to fund them to try to literally get off the ground.
"This modern mentality of very large well-funded private organisations can perhaps make some progress towards space travel."
He added that achieving the mission to land humans on Mars would depend on the willingness of governments and the public to back the idea.
But Brown pointed out that the Apollo missions which landed the first humans on the moon more than four decades ago were an example of what can be done in an "incredibly short time scale".
"With enough money and enough bright minds, these sorts of projects are achievable," Brown said.
"Essentially, the hard work on Apollo began in the late 1950s/ early 1960s, and by the mid-1970s, 12 humans had walked on the moon.
"But the level of financial and technological commitment to a project like that is pretty immense and it needs to be sustained."
LIFE ON MARS
ONCE the journey to Mars is complete, the first human settlers on the planet will face the complex task of building a society from scratch. The location of the settlement, which will comprise a series of inflatable pods, will be primarily based on where there is a high water content in the soil. The water will be extracted by heating the soil until it evaporates, then condensing and storing it. Once the astronauts land, they will only have limited food from Earth to use as emergency rations and will grow plants indoors in a mineral nutrient solution. Due to the inhospitable conditions, they will also have to don spacesuits when outside their living pods. The Mars One mission website (mars-one.com) also addresses some of the complex issues about how society will work. It says the astronauts will have to determine how to organise themselves politically, with the preparations for the trip including studying different forms of social structures on Earth. Religious activity and beliefs will be a matter of individual choice for the settlers on the planet. The first inhabitants will also be advised not to have children, due to limited medical facilities and a lack of knowledge about the impact of reduced gravity on an unborn child. But the Mars One project says this will be an important point of research as children will be vital to establish a true settlement on Mars.
Other missions to Mars
The first exploration missions to Mars began in the early 1960s, with a series of probes launched by the Soviet Union, which all ended in failure. In 1965, the US spacecraft Mariner 4 successfully carried out a "flyby" and became the first to obtain close-up pictures of the planet, transmitting a total of 21 images back to Earth. Since then technology has developed so that robotic explorers, which are capable of trekking for miles across the landscape and carrying scientific instruments to tranmit data giving crucial insights about the environment, have been landed on Mars. It is now known that Mars is rocky, cold and dry — but has similarities to Earth includin clouds, seasonal weather patterns, volcanoes and canyons. In the future, the European Space Agency has plans to launch the ExoMars rover, which will be landed in January 2019 to search for evidence of past or present life. The vehicle is expected to operate for around seven months and will be capable of drilling up to two metres underground. US space agency Nasa has also proposed to launch a new robotic science rover in 2020, which will aim to address key questions about the potential for life on Mars.
The would-be astronauts
The 705 would-be astronauts who have got through to the interview stage come from across the world — with 313 candidates who originally come from the Americas, 187 from Europe, 136 from Asia, 41 from Africa and 28 from Oceania. A total of 22 people from Britain have made it through to the next phase. Among them is Alison, 34, from London, who is a laboratory technician and says she has "a child-like wonder about the universe in which we live." Scott, 33, from Birmingham, who is a web developer, says he believes he is an ideal candidate as he "smiles in the face of adversity". He added: "I once saved my friend's life by being decisive and calm under pressure while others around me were panicking and not making decisions." Another candidate, Maggie, 24, says in her application she is doing a PhD in astrophysics at the University of Birmingham and would make it a priority to communicate science if she was given the opportunity to go to Mars. Norbert Kraft, chief medical officer for the Mars One project, said: "We're incredibly excited to start the next phase of Round Two, where we begin to better understand our candidates who aspire to take such a daring trip. They will have to show us their knowledge, intelligence, adaptability and personality."