Artemis II – Day 4: Piloting in Deep Space (April 4, 2026)

A day full of applied science, practical engineering, and little reminders that living in a spacecraft the size of two minivans has its challenges. All set for the big day!

The crew was awakened by "Pink Pony Club" by Chappell Roan—with Orion already 169,000 miles from Earth and 110,700 miles from the Moon. Now closer to the Moon than to home.

Highlights:

Manual Piloting Demonstration

The most technically exciting moment of the day: Christina Koch and Jeremy Hansen took the controls of Orion in deep space for 41 minutes, testing two propulsion modes—six degrees of freedom and three degrees of freedom—to provide engineers with real-world data on the spacecraft's handling far from Earth. Wiseman and Glover will repeat the demo on Day 8 to broaden the perspective—data that will prove valuable for future long-duration missions.

Review of Lunar Science Objectives

The crew reviewed the preliminary list of geological features to be photographed and described during the flyby. A key difference compared to the Apollo missions: those flew at ~70 miles from the surface; Orion will pass at 4,066 miles—much farther away, but with the advantage of viewing the entire lunar disk at once, including the poles.

Second Corrective Burn Canceled... and a Plumbing Problem

Just like on Day 3, the second correction burn was also canceled due to a perfect trajectory. Instead, the team reoriented the spacecraft, pointing a vent toward the Sun to thaw a potential blockage in the wastewater drain line. The toilet was functional, but the crew had backup devices on hand just in case. The second time on the mission that the waste management system has caused a bit of trouble!

Optical Communications: Record Broken

Orion's laser communications system surpassed 100 gigabytes of data transmitted to Earth, including high-resolution images. This infrared technology transmits much more data than traditional radio-frequency systems—a crucial test in preparation for future missions to Mars.

Deep Space Science

The AVATAR payload continued monitoring bone marrow cells derived from the crew's blood to study how the immune system reacts to deep space. The crew also collected saliva samples and continued using actigraphy devices—small, watch-like sensors—to monitor health and sleep. The German DLR’s M-42 radiation sensors also operated normally.

And as a fun side note: the crew took selfies using one of the external cameras located on Orion’s solar panels.