Hayabusa-2 on display at JAXA’s facility in Sagamihara, suburban Tokyo during its unveiling on 31 August, 2014. Photo: Getty Images
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Japan readies space probe for mission to chase asteroid and shoot it with a cannon

Following on from the mixed success of the ambitious Hayabusa-1 mission, Japanese space scientists are almost ready to try again at hunting an asteroid.

While most of the headlines may be going to the European Space Agency's Rosetta probe right now - it being the first craft to enter into orbit around a comet - there are some other impressive space missions in the pipeline which shouldn't be forgotten. One of these was unveiled this week by the Japanese space agency, Jaxa - the asteroid-hunting Hayabusa-2 probe.

When Hayabusa-2 launches in November or December of this year it will begin a near-four year voyage to asteroid 1999 JU3, where it will then spend 18 months surveying the surface and running a series of experiments. By far the most audacious of these will be the "explosively-formed penetrator", which is a sciencey way of saying that missions planners are going to fire a 30cm copper ball from an on-board cannon at the asteroid's surface. The "bullet" is planned to have a relative velocity of roughly 2km/s, or around six times faster than a bullet travels when fired from a handgun - though this explanatory video from Jaxa appears somewhat lethargic by comparison:

The reason scientists want to shoot an asteroid is quite simple - dust from the crater the bullet leaves will reach escape velocity, creating a cloud of debris that Hayabusa-2 can then float through and collect samples from. (Though, just to be safe, the probe will sneak around to the other side of the asteroid in the time it takes for the bullet to reach the surface, just to avoid any debris that comes up at a dangerous speed.) Hayabusa-2 will then return to Earth by 2020, where that dust - containing, it is hoped, carbon, water and other minerals - will be studied for clues as to the nature of the early Solar System, and how life on Earth may have originated.

Besides the cannon, Hayabusa-2 will also carry four different landers. One, the Mobile Asteroid Surface Scout (Mascot), has been built by the French and German space agencies, is essentially a small laboratory in a box which will be able to take measurements of the conditions on the asteroid's surface for 16 hours after landing. Rather wonderfully, it will be able to "hop" twice using small feet before its batteries run out, tripling the positions on the asteroid's surface it can gather data from. Hayabusa-2 will also carry three Micro/Nano Experimental Robot Vehicle for Asteroid (Minerva-II) landers, more primitive rovers that should also hop languidly across the asteroid's surface, beaming back video footage to Earth and taking measurements. There's something quite beautiful about the idea of a quartet of bouncing robots exploring the surface of a tiny alien world.

In this sense Hayabusa-2 is a bigger, more ambitious version of Hayabusa-1, which only carried one Minerva rover when it arrived at the asteroid Itokawa in 2005. That mission was the first to rendezvous with an asteroid, land, collect samples and then return to Earth, but it was a mission threatened multiple times with failure. Budget cuts pushed back its launch and meant that Nasa couldn't provide it with a lander, a solar flare damaged its solar panels, internal mechanical faults threatened its ability to steer, and at several points scientists lost contact with it. It very nearly didn't have the ability to return to Earth, and, perhaps most tragically, its Minerva hopper was released at the wrong time - it missed the asteroid, floating away into space.

However, the samples that Hayabusa-1 did manage to retrieve were of immense scientific importance (once they'd been recovered from the Australian outback) - and the mission was seen as a source of national pride in Japan, becoming the subject of movies and toys. Reporting on the unveiling this week, the Japan Times quotes mission leader Hitoshi Kuninaka as "grateful" that the new probe is finally complete, and hopeful that, this time, nothing goes wrong. “Of course, I hope things will go smoothly. We have had many difficulties in the process of developing the new asteroid probe. Space is never an easy place.”

Impactors like Hayabusa-2 are not new - Nasa's Deep Impact probe used a projectile in 2005 to stir up a cloud of debris it could then fly through and analyse - but the scale of the mission's ambition is uniquely large. It will briefly appear in the news again when it launches later this year, but the thing about probes like this - as we're seeing with Rosetta - is that they're investments which generate their own wonderful form of interest. Rosetta took ten years to reach its comet, making it almost as old as Hayabusa-1, but when it did remind of us of its lonely voyage it was with spectacular, gorgeous photographs. 2017 should hopefully bring us all another set of gifts.

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

Davide Restivo at Wikimedia Commons
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Scientists have finally said it: alcohol causes cancer

Enough of "linked" and "attributable": a new paper concludes that alcohol directly causes seven types of cancer.

I don't blame you if you switch off completely at the words "causes cancer". If you pay attention to certain publications, everything from sunbeds, to fish, to not getting enough sun, can all cause cancer. But this time, it's worth listening.

The journal Addiction has published a paper that makes a simple, yet startling, claim: 

"Evidence can support the judgement that alcohol causes cancer of the oropharynx [part of the throat], larynx, oesophagus, liver, colon, rectum and [female] breast"

So what's especially significant about this? 

First, scientists, unlike journalists, are very wary of the word "causes". It's hard to ever prove that one action directly led to another, rather than that both happened to occur within the same scenario. And yet Jennie Connor, author of the paper and professor in the Preventive and Social Medicine department at the University of Otago, New Zealand, has taken the leap.

Second, alcohol not only causes cancer of one kind – the evidence supports the claim that it causes cancer at seven different sites in our bodies. There was weaker evidence that it may also cause skin, prostate and pancreatic cancer, while the link between mouth cancers and alcohol consumption was the strongest. 

What did we know about alcohol and cancer before?

Many, many studies have "linked" cancer to alcohol, or argued that some cases may be "attributable" to alcohol consumption. 

This paper loooks back over a decade's worth of research into alcohol and cancer, and Connor concludes that all this evidence, taken together, proves that alcohol "increases the incidence of [cancer] in the population".

However, as Connor notes in her paper, "alcohol’s causal role is perceived to be more complex than tobacco's", partly because we still don't know exactly how alcohol causes cancer at these sites. Yet she argues that the evidence alone is enough to prove the cause, even if we don't know exactly how the "biologial mechanisms" work. 

Does this mean that drinking = cancer, then?

No. A causal link doesn't mean one thing always leads to the other. Also, cancer in these seven sites was shown to have what's called a "dose-response" relationship, which means the more you drink, the more you increase your chances of cancer.

On the bright side, scientists have also found that if you stop drinking altogether, you can reduce your chances back down again.

Are moderate drinkers off the hook?

Nope. Rather devastatingly, Connor notes that moderate drinkers bear a "considerable" portion of the cancer risk, and that targeting only heavy drinkers with alcohol risk reduction campaigns would have "limited" impact. 

What does this mean for public health? 

This is the tricky bit. In the paper, Connor points out that, given what we know about lung cancer and tobacco, the general advice is simply not to smoke. Now, a strong link proven over years of research may suggest the same about drinking, an activity society views as a bit risky but generally harmless.

Yet in 2012, it's estimated that alcohol-attributable cancers killed half a million people, which made up 5.8 per cent of cancer deaths worldwide. As we better understand the links between the two, it's possible that this proportion may turn out to be a lot higher. 

As she was doing the research, Connor commented:

"We've grown up with thinking cancer is very mysterious, we don't know what causes it and it's frightening, so to think that something as ordinary as drinking is associated with cancer I think is quite difficult."

What do we do now?

Drink less. The one semi-silver lining in the study is that the quantity of alcohol you consume has a real bearing on your risk of developing these cancers. 

On a wider scale, it looks like we need to recalibrate society's perspective on drinking. Drug campaigners have long pointed out that alcohol, while legal, is one of the most toxic and harmful drugs available  an argument that this study will bolster.

In January, England's chief medical officer Sally Davies introduced some of the strictest guidelines on alcohol consumption in the world, and later shocked a parliamentary hearing by saying that drinking could cause breast cancer.

"I would like people to take their choice knowing the issues," she told the hearing, "And do as I do when I reach for my glass of wine and think... do I want to raise my risk of breast cancer?"

Now, it's beginning to look like she was ahead of the curve. 

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.