HOUSTON, TX — For 40 minutes on April 5, 2026, Mission Control at Johnson Space Center fell silent as the Orion spacecraft slipped behind the lunar horizon. The planned communications blackout, a consequence of the Moon blocking direct radio signals to Earth, marked one of the most suspenseful yet anticipated phases of the Artemis II mission.
- The Science of the Silence
The “loss of signal” (LOS) began at approximately 6:44 PM ET as the spacecraft commenced its closest approach to the lunar surface.
The Obstacle: Because Orion orbits the Moon, it eventually enters the “lunar shadow,” where the bulk of the Moon physically blocks radio waves from reaching Earth’s Deep Space Network.
The Relay Gap: Unlike Earth-orbiting satellites, there is currently no permanent relay infrastructure (like the planned Lunar Gateway or specialized relay cubesats) positioned to bounce signals from the Moon’s far side back to Houston.
The Duration: NASA engineers predicted and accounted for a 40-minute window during which no telemetry, data, or voice communication was possible.
- Life Behind the Moon: What the Crew Experienced
While the world waited for a signal, the crew—Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen—were far from idle.
Autonomous Operations: Orion’s onboard computers handled navigation independently, while the crew followed a strict “dark phase” checklist.
Breathtaking Views: It was during this period that the crew captured high-resolution imagery of the Orientale Basin, a massive impact crater on the Moon’s western edge rarely seen in such detail.
A New Human Record: During this lunar loop, Artemis II reached a distance of over 252,000 miles from Earth, officially breaking the record for the farthest humans have ever traveled into deep space—surpassing the 1970 record held by Apollo 13.
- Re-Acquisition of Signal (AOS)
At roughly 7:24 PM ET, Orion emerged from the lunar limb. The restoration of the “S-band” and “Ka-band” links confirmed that all systems were nominal and the spacecraft had successfully utilized the Moon’s gravity for its free-return trajectory.
“Communication restored. Orion is looking sharp on the home stretch,” Mission Control announced to a round of applause.
Artemis II Mission Timeline: The Home Stretch
| Phase | Status | Details |
| Lunar Flyby | COMPLETED | Passed behind the Moon on April 5, 2026. |
| Deep Space Record | ACHIEVED | Reached 252,000+ miles from Earth. |
| Earth Return | IN PROGRESS | On a gravity-assisted path back to Earth. |
| Target Splashdown | EST. APRIL 12 | Pacific Ocean, off the coast of California. |
The Apollo Legacy
The blackout is a rite of passage for lunar explorers. During the Apollo 13 mission, the blackout lasted longer than expected due to the spacecraft’s altered trajectory, causing intense anxiety on the ground. For Artemis II, the precision of modern tracking meant the signal returned within seconds of the predicted time.