On
6 August 1945, the US attacked the Japanese city of Hiroshima with an
atomic bomb in a bid to end the second world war. Seventy years after
the devastating power of nuclear weapons was first demonstrated, nine
states retain them in their arsenals
The Manhattan Project
US atomic weapons research began after nuclear fission
was discovered by German scientists in 1938, prompting fears of a Nazi
bomb. After Japan attacked Pearl Harbor in 1941, work centred on the
Manhattan Project, led by Robert Oppenheimer at Los Alamos in New
Mexico. Germany had already surrendered when the first nuclear weapon
test took place on 16 July 1945, but war in the Pacific continued.
The attacks
After the successful test US president Harry Truman
authorised the use of two weapons against Japan, arguing it would be a
quicker and less bloody way to secure surrender than an invasion. There
was no capitulation after the first bomb, codenamed Little Boy,
destroyed more than 10 sq km of Hiroshima on 6 August 1945. Three days
later the more powerful Fat Man device hit Nagasaki.
The casualties
Estimates of people killed in the immediate aftermath of
the two bombings and the months that followed range as high as 246,000.
Many of the survivors suffered horrific burns and the enduring effects
of radiation illnesses. With more attacks planned by the US, Japan
surrendered on 15 August.
Cold war follows world war
The USSR, which had spies in the Manhattan project,
tested its first nuclear bomb in 1949. Increasingly powerful
thermonuclear devices were tested in remote parts of the world,
culminating with the Soviet Tsar Bomba which produced an explosion
visible 1,000 kilometres away and a mushroom cloud taller than Everest.
Mutually assured destruction
Throughout the 1960s, the superpowers developed huge
arsenals. According to the doctrine of mutually assured destruction
(MAD), this made nuclear war unlikely as neither side could ever
eliminate the other’s ability to retaliate. The 1970 non-proliferation
treaty was designed to restrict the capability to existing nuclear
powers and enshrine a commitment to disarmament, but other states were
already pursuing their own programs.
Disarmament delayed
The collapse of the Soviet Union in 1991 removed the
cold war's uneasy certainty. There are now nine known nuclear powers,
chief among them the US and Russia, which retain formidable stockpiles
even after substantial disarmament. Only South Africa has ever developed
and then relinquished nuclear weapons. Ukraine surrendered its
Soviet-era weapons in 1994 in exchange for a guarantee of its
territorial integrity.
The doomsday clock
Since 1947, the Bulletin of the Atomic Scientists has
been publishing a yearly assessment of the risk of global catastrophe in
the form of a clock counting down to midnight. In 2015, with climate
change now included as a risk, it stands at three minutes to midnight,
as existing powers upgrade their arsenals. Ongoing risks to humanity
include further proliferation, a nuclear terrorist attack and the
problem of radioactive waste.
Richard Hollingham meets the
team who keep astronauts safe - and tidy - as they cope with the daily
challenges of conducting science in space.
BBC news
By Richard Hollingham
28 July 2015
In a darkened room, deep within the
high-security perimeter of Redstone Arsenal, a US army base in
Huntsville, Alabama, eight men and women sit behind concave banks of
computer monitors, streams of data reflecting across their faces.
One
of the women will occasionally speak into her headset, although she
speaks so quietly it is difficult to make out more than a few words.
Along
the wall in front of them, screens display images of the Earth, graphs,
timelines and – as we watch – an astronaut’s backside as he floats
through a hatch 400 kilometres above the planet.
The control room is used to monitor the effects of long-duration missions on astronauts (Credit: Nasa/Science Photo Library)
Staffed round the clock, this is Nasa’s Payload Operations Integration Center – the control hub
for all the science experiments on the International Space Station
(ISS). Here, every working minute of the orbiting astronauts’ days are
accounted for, monitored and – if necessary – adjusted. Houston may get
all the glory but this little-known control room, part of the Marshall Space Flight Center, is the hub of space station science.
“We
are the go-betweens,” says payload communications manager Sam Shine.
“We are the interface between the scientists and the crew on board the
space station.”
‘Very tricky’
In
fact Shine is one of the few people on Earth – along with the Capcom
(Capsule Communicator) in Houston – able to talk directly to the crew on
the ISS, looking after them as they work through their daily science
routines.
“It’s very tricky,” says Shine. “We have language
barriers, we have time zone differences – sometimes trying to work with
an Italian principal investigator and get the information they need up
to, perhaps, a German crew member can be a bit tricky.”
Since its
completion in 2011, the $100bn (£64.5bn) ISS has been all about the
science. The walls, ceiling and floor of its US, Russian, European and
Japanese laboratories are crammed with experiments, and astronauts spend
an increasing amount of time as orbiting research technicians.
The crew are monitored while working to make sure they don't misplace vital equipment (Credit: Nasa/Science Photo Library)
“If you name a discipline of science, we are
probably doing that kind of experiment on board,” says Shine. Studies in
this unique microgravity research lab range from investigating plant
growth to understanding the properties of liquid metals.
Much of
the science overseen from the control room in Alabama is concerned with
studying the effects of space on the astronauts themselves, such as the bone and muscle wastage they experience. This is essential research if humans are ever to leave their home world for any length of time.
When living in space, is comfort food good for you?
Scientists
are also studying the psychological challenges of living away from
Earth in an isolated metal box, eating reconstituted meals, drinking
recycled urine, with only work colleagues for company.
One of the
most intriguing of these experiments – Astro Palate – has been devised
by food and nutrition scientists at the University of Minnesota. Among
other things, it seeks to understand how food can be used to reduce
stress. In other words, when living for a long time in space, is comfort
food good for you?
“We may have astronauts do a task they don’t
enjoy such as vacuuming the space station,” says Shine. “We then have
them take a survey to see how they feel about it, then let them eat some
comfort food – perhaps chocolate pudding – and take another survey.”
Comfort food like chocolate pudding can be a powerfully persuasive tool (Credit: Getty Images)
“We’re starting to understand ways of making our
crews feel at home as they’re in space for longer and longer
durations,” she adds.
Another study involves astronauts keeping
journals of their life on board the station – an attempt to get honest
accounts of their feelings, stresses, tensions or homesickness. Because
only the researcher compiling the results of the project reads them, the
hope is that the crew are more likely to be candid.
The fourth month of the mission is when the crew is most likely to want to come home
“One
of the most interesting findings is that the fourth month of the
mission is when the crew is most likely to want to come home,” says
Shine. “They’re getting tired of being on the space station and they
want to see their families.”
As most missions to the ISS are now
between six months and a year in duration, Nasa may therefore want to
consider sending up some more chocolate pudding.
Lost in space
To
help cope with the daily frustrations of living on board a cluttered
orbiting laboratory, the Alabama team is even responsible for the
astronauts’ lost property. It is the job of the Stowage Officer to keep
track of every item on the ISS. Shine describes it as “one of the
hardest jobs in the space programme”.
Sometimes astronauts don’t put their things away, just like us here on Earth
“Sometimes
astronauts don’t put their things away, just like us down here on
Earth,” says Shine. “They’ll call down looking for a wrench or something
and it’s not where we thought it was, so it’s the job of the stowage
officer to go back through the history of where it was last seen and
locate it.”
It is the space equivalent of losing your keys and
trying to remember where you last had them. The problem is that if you
put down your spaceship keys, there is a good chance they will float off
somewhere else.
“We’re looking over the astronauts’ shoulders so
if we see something float away we’ll let the crew know,” says Shine. “A
lot of the time we find things collected in vents.”
It’s always
been the case that behind every astronaut there are thousands – if not
tens of thousands – of support staff. The difference today, as we enter
an era of longer duration missions, is that they are just as likely to
be an expert on comfort food or space station storage as a rocket
scientist.
