After the euphoria, a dilemma: do the Rosetta scientists stick - or twist?
The Philae lander is said to be "stable" on comet 67P, but not anchored.
Firing the space harpoons - and that's a fun phrase to write - might blast the lander back off into space.
So too might starting the drill, vital if scientists are to analyse what the comet is made of.
At 1pm UK time today, we'll find out what they've decided.
But even if Philae slips from its unknown perch and falls into space, the Rosetta has been a huge success.
Simply put, it's very, very cool. And that's important for the technology sector today.
For the last few years, the technology narrative has been about private enterprise - that it's start ups, not governments, which drive innovation always seeking the holy grail of disruption.
The iPhone, a supercomputer in your pocket; Google, the most advanced artificial intelligence in the real world; Uber, a quicker way of ordering taxis. All from Silicon Valley - not cobwebbed Europe.
Government and government agencies are too cumbersome, too slow, too deliberate, the argument goes. Compare that to Facebook’s famous motto: move fast and break stuff.
It's a point Peter Thiel, the co-founder of Paypal, likes to make: last week at the Web Summit in Dublin - a world's fair for startups - he told me that innovation no longer comes from government.
But Rosetta has proved that long-term planning, massive international collaboration, a huge development team - all the things that Silicon Valley professes to despise - can deliver spectacular and inspiring results.
"Move slowly, really hope stuff don't break" works too.
And we should celebrate that - because big government research ends up in our pockets.
As Mariana Mazzucato shows in her book The Entrepreneurial State, the core technologies that make up the iPhone, from GPS to the touchscreen, were the result of government research.
The same goes for the internet and for the world wide web (developed by Tim Berners-Lee at CERN).
It's far too early to say what commercial benefits Rosetta will lead to - and it's an ungraciously mercantile approach when the science is so wonderful on its own.
We can leave it to Silicon Valley - and other start up hubs around the world - to figure out how to monetise the technology, whether that's showing us more adverts or selling us more stuff.
But old Europe and big government this week reclaimed innovation, and three cheers for that.