Today’s the Day! Artemis II Crew Ready for Lunar Flyby

Today four astronauts will fly around the Moon for the first time since 1972. The crew of Artemis II is closing in on the Moon and around lunchtime will surpass the record for the furthest anyone has traveled from Earth.  For about seven hours they will make scientific observations of the lunar surface, including parts human eyes have never seen. They also will be out of contact with Earth for 40 minutes when the Moon blocks communications.

Artemis II is a test flight of the Orion system and will not orbit the Moon, much less land. Instead it is on a “free-return” trajectory that slingshots them around the Moon and returns them to Earth even if the propulsion system doesn’t perform as planned.

NASA is providing 24/7 coverage of the Artemis II mission on YouTube, and at 1:00 pm ET has an additional livestream for the flyby and it will air on NASA+, too. NASA says these streaming services also will cover it: Amazon Prime, Apple TV, Hulu, Netflix, HBO Max and Roku.

The Artemis II crew entered the sphere of lunar influence — past the point where lunar gravity takes over from Earth’s gravity — just after midnight ET.

At 1:56 pm ET, they will be 248,655 miles (400,171 kilometers) from Earth, the furthest humans have ever flown before. That record was set by the Apollo 13 crew and at 2:10 pm ET the Artemis II crew will make remarks about that milestone (audio only) as they continue on their own route that takes them out to 252,760 miles (406,778 kilometers).  That’s where they swing around and start heading back to Earth, landing off the coast of California on Friday night at 8:07 pm EDT.

NASA’s updated list of key events today starting at 1:00 pm ET is as follows:

• Live coverage begins at 1 p.m. on Monday, April 6, and continues through 9:45 p.m.
• 1:30 p.m.: NASA hosts a conversation between the crew and the science officer in NASA’s Mission Control Center at the agency’s Johnson Space Center in Houston, to go over the objectives and timeline for the flyby.
  • Because the Sun’s angle on the Moon shifts by about one degree every two hours, the crew could not know the exact lighting conditions to expect on the lunar surface until after launch. This briefing provides one final opportunity to review details before the flyby begins.
• 1:56 p.m.: The Artemis II crew is expected surpass the record previously set by the Apollo 13 crew in 1970 for the farthest humans have ever traveled from Earth.
  • The Apollo 13 crew traveled 248,655 miles from Earth; Artemis II will reach a maximum distance of 252,760 miles from Earth, surpassing the record by about 4,105 miles. The crew is expected to make remarks on the milestone around 2:10 p.m.
• 2:45 p.m.: The seven-hour lunar observation period begins. Crew will see both the near and far sides of the Moon as the observation period begins.
  • Because room at Orion’s windows is limited, the crew will divide into pairs, with two crew members observing for 55 to 85 minutes, while the other pair exercises or works on other tasks.
• 6:44 p.m.: Mission control expects to temporarily lose communication with the crew as Orion passes behind the Moon.
• 7:02 p.m.: Astronauts will make their closest approach to the Moon (4,070 miles), then reach its farthest point from Earth at 7:07 p.m.
  • At this distance, the Moon will appear to the astronauts about the size of a basketball held at arm’s length. They also may be the first humans to see some parts of the Moon’s far side with the unaided eye.
• 7:25 p.m.: NASA’s Mission Control Center should re-acquire communication with the astronauts.
• 8:35 p.m.: Orion enters period with Moon eclipsing the Sun and continues until 9:32 p.m.
• 9:20 p.m.: The flyby observation period wraps, and crew will begin transferring some of the imagery to the ground. NASA’s science team will review the images and observations overnight, and then discuss with crew the following day, while the experience is still fresh.

Since launch on April 1, the crew has been testing out the Orion capsule, which they named Integrity. Orion has only flown once before on an uncrewed test flight in 2022. This time it’s equipped with life support systems that are working well overall.

The one exception is the part of the toilet system that vents urine overboard. The line froze and the crew temporarily had to use a backup system — bags called Collapsible Contingency Urinals.  NASA solved the problem by pointing that part of the spacecraft towards the Sun, but Ascent Flight Director Rick Henfling conceded during a press briefing yesterday they are still trying to figure out exactly what is wrong. “There’s a lot of theory and textbook work done when you assume it’s pure water being exposed to a vaccum, but when you introduce the variable of it being wastewater, there’s other complex phenomena that we don’t quite yet understand that are factoring into that vent line.” For now, however, it’s fine.

Orion’s propulsion system also is performing well. The Orbital Manuevering System (OMS) engine that fired on April 2 for 5 minutes 50 seconds to put them on their Trans-Lunar Injection (TLI) trajectory was so precise that two brief outbound correction burns weren’t needed. They did fire the third burn yesterday for 17.5 seconds.

Verifying Orion’s ability to support a crew in space and return them safely to Earth are primary goals of the Artemis II mission, but the crew is also trained on scientific observations of the Moon as they swing around the farside. The Moon and Earth are tidally locked, with the Moon rotating at the same speed it orbits Earth so the nearside always faces toward Earth and the farside always faces away.

Robotic spacecraft like NASA’s Lunar Reconnaissance Orbiter have done detailed studies of the farside, but the Apollo astronauts are the only humans to see it with their own eyes. Kelsey Young, Artemis Science Flight Operations Lead, says that’s what makes the difference — seeing the surface through human eyes which are good at “teasing out nuances” that cameras on LRO cannot discern.

That’s what they’ll be doing with the crew members alternately looking at the surface with their eyes or with three cameras they brought with them. They are using the cameras already to return stunning images of the Earth like this one.

 

This article has been updated.