Artemis II Launches: Humanity Returns to Deep Space

SLS leaps off LC-39B carrying the Artemis II Mission // Photo: Ryan Bale

On April 1, 2026, NASA’s Space Launch System roared to life at Kennedy Space Center, sending four astronauts beyond low-Earth orbit for the first time in more than half a century. Liftoff occurred at 6:35p.m. EDT from Launch Complex 39B, marking a defining moment in the Artemis program and a return to human exploration of the Moon.

Crew Walkout: A Historic Departure

Hours before launch, the Artemis II crew emerged from the Neil A. Armstrong Operations and Checkout Building in a moment reminiscent of Apollo-era traditions. The walkout, which took place at 1:49 p.m. EDT, was met with applause as Commander Reid Wiseman led Pilot Victor Glover, Mission Specialists Christina Koch, and Jeremy Hansen toward their ride to the pad.

Suit leak checks, final weather briefings, and spacecraft ingress followed. By mid-afternoon, the crew was strapped inside Orion, completing communications checks and preparing for one of the most consequential launches in modern spaceflight.

Countdown Challenges: Issues Resolved in Real Time

Despite a largely smooth countdown, several technical issues surfaced in the final hours:

• Flight Termination System (FTS) Concern: A last-minute issue briefly placed the mission in a “No-Go” status. Engineers quickly resolved the problem, clearing it as “no longer a constraint” before launch.

• Battery Instrumentation Issue: A separate concern involving battery readings required evaluation but was ultimately determined not to impact flight safety.

• Range/Safety Checks: Minor range-related concerns were worked in parallel, with teams verifying system readiness.

These issues triggered built-in holds and real-time troubleshooting, demonstrating the layered safety systems embedded in modern human spaceflight.

4 RS-25 Main Engines and 2 Solid Rocket Booster propel the SLS rocket off LC-39B Photo Ryan Bale

Liftoff: The Most Powerful Rocket in Operation

At T-0, the twin solid rocket boosters and four RS-25 engines ignited, producing over 8.8 million pounds of thrust, making SLS the most powerful operational rocket in the world.

The vehicle cleared the tower and accelerated downrange over the Atlantic:

• ~2 minutes: Solid rocket booster separation

• ~8 minutes: Core stage main engine cutoff and separation

• Shortly after: Orion spacecraft reached orbit and began initial operations

Within minutes, the crew crossed the boundary of space, beginning their journey into cislunar space.

The Rocket: SLS and Orion by the Numbers

Space Launch System (Block 1):

• Height: ~322 feet

• Liftoff thrust: ~8.8 million pounds

• Core stage engines: 4 RS-25 (Space Shuttle heritage)

• Boosters: 2 five-segment solid rocket boosters

Orion Spacecraft:

• Crew capacity: 4 astronauts

• Designed for deep space missions beyond low-Earth orbit

• Equipped with life support, radiation protection, and reentry systems for lunar return

Together, SLS and Orion form NASA’s backbone for deep space exploration.

The Mission Ahead: A 10-Day Journey Around the Moon

Artemis II is a 10-day mission designed to validate Orion’s systems with a crew onboard before future lunar landings.

Flight Profile:

1. Initial Earth Orbit

   • Systems checkout

   • Manual piloting demonstrations

2. Trans-Lunar Injection (TLI)

   • Critical burn sending Orion toward the Moon

3. Lunar Flyby

   • Free-return trajectory around the far side of the Moon

   • Distance exceeding ~248,000 miles from Earth

4. Return to Earth

   • High-speed reentry

   • Pacific Ocean splashdown on Day 10

This trajectory ensures that even in the event of propulsion issues, the spacecraft will naturally return to Earth using lunar gravity.

Early Flight Notes

In the hours following launch, the crew began orbital operations, including propulsion burns to prepare for translunar injection. Minor onboard anomalies, such as a reported fault light during early system checks, are being evaluated by ground teams but have not impacted mission progress.

SLS leaps off LC-39B carrying the Artemis II Mission // Photo: Ryan Bale

A Defining Step Toward Artemis III

Artemis II is more than a mission—it is a proving ground. Every system, from life support to navigation, is being tested with humans onboard for the first time since Apollo.

Its success directly enables Artemis III, which aims to land astronauts on the Moon for the first time in over 50 years and establish a sustained human presence on the lunar surface.

For now, four astronauts are once again leaving Earth behind—heading toward the Moon, carrying with them the next chapter of human space exploration.