Science news digest – 4th March 2013
In the science news this week, a manned mission to Mars, doctors claim to have ‘cured’ HIV in an infant, and finally… Sir Ranulph Fiennes latest expedition hopes are dashed.
Manned Mars mission proposed by multimillionaire
Plans to launch the first manned mission to Mars were announced last week by US multimillionaire Dennis Tito. The ambitious project will see a two person vehicle travel to Mars, do a slingshot around the planet, and then travel back to Earth – a journey that will take 501 days in total.
During the press conference, Tito explained that he was looking for a man and a woman – probably a married couple – to crew the mission, which will be one of the riskiest space flights ever undertaken.
The Guardian reported that many believe that this mission raises the bar of what humans are prepared to risk in order to travel in space, adding that a national space agency, such as NASA, would never allow this level of danger.
"It's plausible, but it's an eye-wateringly uncomfortable and risky mission design. What is important here is that this is a philosophical shift in the approach to and acceptance of risk," Kevin Fong, director of the Centre for Space Medicine at UCL, told the Guardian.
The team still need to develop life-support systems and radiation protection for the mission, and heat shields that can withstand the re-entry into Earth’s atmosphere at twice the usual speed.
There will also be little time for test flights, so the mission will rely on using tried-and-tested equipment where possible, and ground-based testing.
One of the biggest dangers for the crew will be the high levels of radiation that they will be exposed to once outside of the Earth’s magnetic field. There is a constant flux of galactic cosmic rays, which originate from outside the solar system. The rays can cause damage to biological tissue, and greatly increase astronauts’ likelihood of developing cancer in their lifetimes.
However, there is also another source of potentially dangerous radiation that the astronauts will need to worry about – the Sun. Radiation from solar flares and coronal mass ejections – incredibly intense blasts of radiation – can kill. On a typical journey to Mars – which is longer than the slingshot route proposed for this voyage – it is estimated that there is a 10 per cent chance of experiencing at least one fatal solar blast, and more than a 30 per cent chance of experiencing a blast that would kill 35 per cent of people within 50 days. However, the proposed launch date on 5th January 2018 corresponds with the dip in the 11-year cycle of solar activity, meaning that any flares would be less intense and less frequent.
One solution to protect the astronauts from the radiation will be to line the walls of the craft with the drinking water and food that the astronauts will need, as well as their faeces, reported New Scientist.
“It's a little queasy sounding, but there's no place for that material to go, and it makes great radiation shielding," says Taber MacCallum, a member of the mission team.
The waste will be dehydrated once placed in bags, which will line the wall of the craft. The water can also be cleaned and then used again by the crew.
Food will also be used as a shield for the astronauts, although it wouldn’t be dangerous, as it would merely block the radiation rather than becoming a radioactive source itself.
US infant “cured” of HIV by early drug treatment
Doctors from the US claim to have cured a baby girl who was born with HIV by starting drug therapy within 30 hours of her birth, reported the BBC.
The child is now two-and-a-half years old and has been off of the medication for about a year with no signs of infection.
However, more tests need to be done before determining if this treatment would work for others.
The baby was given a cocktail of widely available drugs, known as antiretroviral therapy. The mother discovered she was HIV positive during her pregnancy and because she had received no prenatal treatment, the doctors knew that the child was at high risk of being infected.
This led the team to treat the baby within 30 hours of her birth with three standard HIV-fighting drugs before she had even been confirmed as being infected.
"I just felt like this baby was at higher-than-normal risk and deserved our best shot," said Dr Hannah Gay, a paediatric HIV specialist at the University of Mississippi Medical Center.
The treatment was continued for 18 months, at which point the child disappeared from the medical system. Five months later, the mother and child turned up again but had stopped receiving treatment during this time.
Following tests, it was found that the infection had not returned in the child, which would normally happen when treatment is stopped for any length of time.
Dr Rowena Johnston from the Foundation for Aids Research, told the BBC that it appeared that early treatment wiped out the virus before it could form reservoirs of dormant cells within the body.
"I actually do believe this is very exciting.
"This certainly is the first documented case that we can truly believe from all the testing that has been done.
"Many doctors in six different laboratories all applied different, very sophisticated tests trying to find HIV in this infant and nobody was able to find any.
"And so we really can quite confidently conclude at this point that the child does very much appear to be cured."
However, others have warned that there needs to be long-term follow up of the child in order to determine whether this really is the case.
Sir Ranulph Fiennes leaves Antarctica
Sir Ranulph Fiennes has had to abandon his latest attempt at crossing Antarctica due to severe frostbite in his left hand. The frostbite may have been caused by the onset of type-two diabetes, Sir Ranulph told the BBC, which had been hinted at during an earlier medical check-up when he was still in the UK.
However, the expedition will still go ahead on schedule, and Sir Ranulph will now take on the role of fundraiser back in the UK for the charity they are raising money for.