On the downside, their toilet is on the blink again.
The three Americans and one Canadian are set to reach their destination on Tuesday AEST, photographing the mysterious lunar far side as they zoom around.
It's the first moon-bound crew in more than 53 years, picking up where NASA's Apollo program left off.
"The earth is quite small, and the moon is definitely getting bigger," pilot Victor Glover reported.
Until the Orion capsule's bathroom is fixed, Mission Control has instructed the astronauts to break out more of the backup urine collection bags.
The so-called lunar loo malfunctioned following Wednesday's lift-off and has been hit-and-miss ever since.
Engineers suspect ice may be blocking the line that is preventing urine from completely flushing overboard. The toilet is still open for No.2 business.
Debbie Korth, NASA's Orion program deputy manager, said the astronauts have also reported a smell coming from the bathroom, which is buried in the floor of the capsule with a door and curtain for privacy.
"Space toilets and bathrooms are something everybody can understand ... it's always a challenge," she said, noting that the space shuttle toilet was also often on the fritz.
John Honeycutt, chair of the mission management team, said it is human nature to be interested in the space commode, and even though it is "in a good state right now", he'd like it to be working at 100 per cent.
"They're OK," he said of the astronauts. "They trained to manage through the situation."
Artemis II is poised to set a distance record for humans, travelling more than 400,000 kilometres from Earth before hanging a U-turn behind the moon and heading home without stopping or entering lunar orbit. The record is currently held by Apollo 13.
The Canadian Space Agency celebrated the nation's role in the mission, speaking from Quebec with astronaut Jeremy Hansen as he headed toward his lunar rendezvous. Hansen is the first non-US citizen to fly to the moon.
"Today he is making history for Canada," Canadian Space Agency president Lisa Campbell said.
"As we watch him taking this bold step into the unknown, let his journey remind us that Canada's future is written by those who dare to reach for more."
In the live televised linkup, Hansen said he's already witnessed "extraordinary" views from NASA's Orion capsule.
Hansen, Glover, Reid Wiseman and Christina Koch are the world's first lunar astronauts since Apollo 17's crew of three in 1972. Koch and Glover are the first female and first Black astronauts to the moon, respectively.
Their nearly 10-day mission - ending with a Pacific splashdown on April 10 - is the first step in NASA's bold plans for a sustainable moon base. The space agency is aiming for a landing by two astronauts near the lunar south pole in 2028.
