Good morning. A leaky rocket has delayed NASA’s 50-years-in-the-making return to the moon – more on that below, along with Quebec’s surreal legislative session and Frank Stronach’s criminal trial. But first:

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Artemis II is a crucial step in NASA’s US$100-billion gamble to push the limits of space exploration. It’s the first attempt in more than half a century to send people beyond low Earth orbit, the region a few hundred kilometres above sea level where the International Space Station is found. In fact, Artemis II could take astronauts further than they’ve ever travelled – all the way past the far side of the moon, much of which has never been seen by human eyes. It will pave the way to put astronauts near the lunar South Pole as soon as next year, with the ultimate goal of dispatching them on a mission to Mars.

But first, Artemis II has to get off the ground.

That part hit a snag yesterday, when NASA called off the flight after troubles with its launch system. Midway through an elaborate dress rehearsal, while the giant rocket filled with 2.6 million litres of super-cold fuel, engineers detected a hydrogen leak by the bottom of the tanks. This is (checks space notes) bad, as is the loose valve caught at the top of the rocket, along with the dropouts in audio communications. The four-astronaut crew – including Jeremy Hansen of the Canadian Space Agency – were promptly hauled out of quarantine and told they wouldn’t launch before March.

The new crew

If “Artemis hydrogen leak” sounds suspiciously familiar, it’s because the mission’s predecessor, Artemis I, suffered the same problem three years ago. That setback, along with scheduling issues and two separate brushes with hurricanes, delayed its launch for months, until the uncrewed flight finally took off in mid-November, 2022, on a 26-day spin around the moon.

Artemis I provided the first complete test of NASA’s 332-foot-tall Space Launch System, the most powerful rocket the agency has ever developed, with enough thrust to fling its Orion spacecraft into lunar orbit at speeds up to 40,000 kilometres an hour. Three mannequins – one full-sized, two legless – were tucked inside the Orion capsule, outfitted with sensors to monitor radiation levels, vibration and acceleration force.

But a key objective for Artemis II is to test Orion’s life-support systems, so NASA needed to ditch the dummies for actual human astronauts. And this time, they’re also going for a less homogeneous crew. Each of the 24 people who ventured to the moon in the 1960s and 70s was a white American man. Now, alongside Commander Reid Wiseman, Artemis II will carry the first woman (mission specialist Christina Koch), the first person of colour (pilot Victor Glover) and, in Canada’s Hansen, the first non-American to make the trip.

On the clock

So when exactly will they make their trip? That could be even trickier than a hydrogen leak. Artemis II has to chart a precise, 10-day route that covers more than one million kilometres, orbiting Earth twice in an ellipse, then pushing around the back of the moon in a figure eight, before heading home with another half-orbit to splash down off California’s coast.

The challenge is that Earth and the moon aren’t static bodies in space: Earth circles the sun, and the moon circles Earth, and everything is also furiously spinning on an axis. NASA can’t just launch its rocket whenever. It has to pick a window that gives Artemis II the correct boost from Earth’s rotation, delivering the Orion spacecraft into high orbit.

Once Orion is in proper alignment, astronauts can burn the engine that lets them slip Earth’s orbit and travel toward the moon – but only if they’re on the right trajectory to then slingshot around using the moon’s gravity so they can safely return to Earth. (You might recall this manoeuvre from Apollo 13, the mission, or else Apollo 13, the movie.) Also, Orion can’t be in the sun’s shadow for more than 90 minutes at a time, because its wings are – what else? – solar-powered.

The earliest date for Artemis II to lift off now shifts to a two-hour window on March 6. Otherwise, there will be just four other chances that month, and six more in April. After yesterday’s failed dress rehearsal, John Honeycutt, the mission’s management team chair, tried to look on the bright side: “The big takeaway was we got a chance for the rocket to talk to us, and it did just that.” I’m told the rocket asked if its fuel could stay in its tank next time.

A day before its planned peace talks with Kyiv, Russia fired hundreds of drones and dozens of missiles at Ukraine’s energy systems, knocking out power during the coldest winter in years. Read the latest on the ceasefire negotiations here.