Five critical steps involved in putting a lander on a comet
How do you land on a comet? This isn't some fantasy from science fiction but the reality facing the people running Esa's Rosetta mission after the successful rendezvous with Comet 67P/Churyumov-Gerasimenko.
Tuesday 11 November has already been pencilled in as the day that the Philae lander will touch down on the mysterious icy body.
If it slips too far beyond that, the comet's orbit will take it closer to the Sun, which means the surface will heat up and maybe become too active for the fragile craft.
So the pressure is now on to come up with a plan.
On Wednesday, the head of landing site selection, Stephan Ulamec, gave a briefing on his latest thinking and I also discussed the challenges with Esa science adviser Mark McCaughrean.
Journey of understanding 'just beginning'
Europe's mission control here at Darmstadt in Germany cannot match the sheer exuberance of Nasa when it comes to celebrating triumphs.
Confirmation that Esa's Rosetta spacecraft had achieved its historic rendezvous with a comet was greeted with applause, wide grins and shouts of "yes, yes!", but none of the wild cheering we saw when Curiosity touched down on Mars two years ago.
Rosetta 'on its final approach'
After a journey that has lasted a decade, Europe's Rosetta spacecraft is now on its final approach to a comet.
One of the scientists leading this European Space Agency (Esa) venture described it as "the sexiest, most fantastic mission ever".
Deep sea mining licences issued
Vast new areas of the ocean floor have been opened up in an accelerating search for valuable minerals including manganese, copper and gold.
In a move that brings closer a new era of deep sea mining, the UN's International Seabed Authority (ISA) has issued seven new exploration licences.
Shuttle diplomacy in climate countdown
A senior British minister is once again launched on a long-haul high-carbon mission of shuttle diplomacy in the cause of tackling climate change.
The target is to try to land an international deal on limiting greenhouse gases at what is billed as a major summit in Paris in late 2015.
Oklahoma drought kindles spectre of 1930s 'Dust Bowl'
A menacing cloud of dust swirling above a parched field in Oklahoma is a disturbing reminder of the power of drought.
All too often here, when the land is baked dry, the winds can strip away an inch of precious topsoil in as little as 24 hours, soil that has taken centuries to form.
How much money can we make from fracking Britain?
How much money can be made from trying to extract oil and gas from the layers of shale that lie beneath Britain?
Answering that is proving to be a surprisingly difficult scientific question because knowing the basic facts about shale is not enough.
Pfizer takeover could delay drug development, says Astra chief
For anyone in the pharmaceutical industry, the Holy Grail is the discovery of what they call a new "molecule", a cleverly-designed compound that proves effective as a treatment.
But achieving this is fiendishly complicated - getting approval has become hugely expensive and success is far from guaranteed.
'Nothing can stop retreat' of West Antarctic glaciers
West Antarctica is one of the least accessible parts of the planet and it takes a huge effort to research the changes under way there. Nearly a decade ago, I joined a flight on an old US Navy patrol plane that made a gruelling 11-hour round trip from the southern Chilean city of Punta Arenas to Pine Island Glacier, which lies among the glaciers featured in these latest studies.
There was no possibility of landing and, if the worst were to happen, there was no-one close enough to offer any kind of rescue. This is research at its most daring. On board was a team from Nasa whose instruments were measuring the elevation and thickness of the ice below us. Even at this stage, it was clear that the glacier, far larger than anything you might see in Europe or North America, was speeding up.
How does Europe wean itself off Russian gas?
Each escalation of the crisis in Ukraine sends a jolt of nervousness far beyond its borders as Europe worries about its energy supplies.
With about one-third of Europe's gas coming from Russia and about half of that gas flowing through Ukraine, these are tense times.