Artemis II, NASA's most daring mission in generations, launches to the Moon - Ars Technica

Overview

Artemis II, NASA’s most daring mission in generations, launches to the Moon

Liftoff of Artemis II with four astronauts occurred at 6:35 pm EDT (22:35 UTC) on Wednesday.

Details

KENNEDY SPACE CENTER, Fla.—Three Americans and one Canadian launched into orbit from Florida’s Space Coast on Wednesday, flying the most powerful rocket ridden by humans on the first leg of a nine-day voyage around the Moon.

Perched atop the 322-foot-tall (98-meter) Space Launch System rocket, the four astronauts lifted off from NASA’s Kennedy Space Center at 6:35 pm EDT (22:35 UTC).

Four hydrogen-fueled RS-25 engines and two solid rocket boosters flashed to life to push the nearly 6 million-pound rocket from its moorings at Launch Complex 39B. The engines and boosters collectively generated 8.8 million pounds of thrust, outclassing NASA’s Saturn V rocket used for Apollo lunar missions.

Moments later, a wave of sound reached spectators a few miles away as the rocket thundered into the sky, leaving an incandescent plume of fire and smoke in its wake.

Commander Reid Wiseman, a 50-year-old Navy captain and former test pilot, calmly radioed updates from the cockpit of the Orion spacecraft at the tip of the SLS rocket. He was joined in the cockpit by pilot Victor Glover (another Navy captain), mission specialist Christina Koch, and Canadian astronaut Jeremy Hansen.

The liftoff of Artemis II is a key moment for NASA. The agency has spent close to $100 billion on elements of the Artemis program over 20 years and now finds itself in competition with China to return humans to the Moon’s surface. Artemis II is also making history in the annals of space exploration. Astronauts last left the Moon in 1972, and no one has been back since.

This mission won’t land. That will have to wait for a future flight, currently targeted for Artemis IV in 2028. NASA is working with Space X and Blue Origin to develop human-rated landers to ferry crews between Orion spacecraft and the lunar surface. Axiom Space is developing new spacesuits for astronauts to wear on the Moon.

Artemis II is testing the transportation system NASA plans to use to get astronauts from Earth to the Moon and then return crews home at the end of their mission. The first major milestone was Wednesday’s successful launch, setting the stage for manual piloting demos, trajectory correction maneuvers, life-support system checkouts, and finally, a loop thousands of miles past the back side of the Moon.

If the mission goes according to plan, the astronauts will reach a distance of 252,799 miles (406,840 kilometers) from Earth on Monday, April 6, farther than anyone has ever traveled from our cosmic oasis. The crew will see parts of the far side of the Moon never seen before by human eyes. Scientists want to compare their naked-eye observations with far-side imagery captured by robotic missions.

The Orion spacecraft will follow a so-called “free return” trajectory, using gravity from its slingshot around the Moon to redirect its course back to Earth. The pull of Earth’s gravity will accelerate the capsule to some 25,000 mph, or 7 miles per second, as it plunges back into the atmosphere to conclude the mission. Splashdown in the Pacific Ocean off the coast of California is scheduled for April 10.

The Artemis II crew, left to right: Jeremy Hansen, Victor Glover, Reid Wiseman, and Christina Koch. The astronauts departed crew quarters to head for the launch pad around four hours prior to liftoff.

Wednesday’s launch set all of that in motion. The SLS rocket surpassed the speed of sound just one minute after liftoff. The launcher’s twin boosters consumed their solid propellant in a little more than two minutes after reaching an altitude of more than 150,000 feet, then jettisoned to fall into the Atlantic Ocean. They won’t be recovered.

The four-engine core stage continued firing for another six minutes, accelerating Artemis II to near orbital velocity. During this burn, the rocket shed its launch abort system and aeroshell panels that protected the Orion spacecraft during the initial climb through the atmosphere. The rocket hit all of its milestone events right on time before the core stage shut off its engines and separated from the Orion spacecraft and upper stage a little more than eight minutes into the flight.

With engines off, the spacecraft coasted through space for more than 40 minutes. Orion extended its four power-generating solar panels before the next major event, a critical burn of the upper stage’s RL10 engine to put the spacecraft into a stable low-Earth orbit. A second firing of the RL10, nearly two hours after launch, will send the spacecraft into a much higher orbit, an elliptical arc extending more than 40,000 miles from Earth, higher than anyone has flown since 1972.

The next mission event will be the separation of Orion from the SLS rocket’s upper stage nearly three-and-a-half hours after launch. At that point, the astronauts will begin one of their first tasks of the mission. After flying a short distance from the rocket, Glover will take manual control of the Orion spacecraft to re-approach the upper stage. Glover will fire thrusters to slowly guide Orion back to the rocket, assessing the ship’s handling characteristics and its responsiveness to manual commands.

The layout of Orion’s cockpit is familiar to Glover, who flew F/A-18 Super Hornets in the Navy. Orion’s manual controls contrast with the touchscreen displays of Space X’s Crew Dragon spacecraft, which Glover flew to the International Space Station on his first trip to space in 2020.

“There are physical rotational hand controllers and translational hand controllers, and this thing that we call a cursor control device, which is something you hold in your hand and hit buttons,” Glover told Ars before the Artemis II mission. “The crew (on Orion) has to be much more proficient to know where to go to see the right information. The Space X vehicle was built so that your kids could jump off their video games and jump in Dragon. A lot of it is intuitive, and that’s a good thing. That’s the paradigm that they are shooting for.”

Like Dragon, Orion is designed to fly on autopilot, but astronauts want to have the ability to take control of the spacecraft if necessary. Future missions will require the Orion spacecraft to dock with lunar landers in orbit around the Earth or the Moon.

“We are essentially going to make sure that the vehicle flies the way that we think it does, that we designed it to do,” Glover said. “We’re not only going to fly the vehicle manually. We’re going to execute all six degrees of freedom, so translating forward, backward, left, right, up, and down, and then also pitch, yaw, and roll.”

This phase of the mission is known as the rendezvous and proximity operations demonstration. The astronauts will not only fly the spaceship. They will also provide verbal feedback on their experiences as Orion moves as close as 30 feet, or 10 meters, from the upper stage. “I’m going to put my communication system … on voice activation, so I can just talk to the ground continuously,” Glover said.

The upper stage will vent all of its hydrogen fuel before Orion moves in close. The maneuvers will last about 90 minutes, enough time for Orion to first approach the nose of the rocket, then fly off the side of the upper stage before a final “breakout burn” to depart the rocket for good.

Wiseman will assist Glover with the manual piloting demo. Koch will make sure the pilots follow the proper procedures. Hansen will have the especially important job of watching the rocket through Orion’s window. On this mission, the spacecraft lacks a rangefinder to measure the distance between Orion and the upper stage.

“We will be using subtended angles, how big the upper stage looks out the window or through a camera,” Glover said. “So we are the primary hazard avoidance system, these eyes, in our assessment of how close we are.”

The pace of activity onboard Orion will slow down after the capsule completes its final backaway from the upper stage. The astronauts will begin activating the ship’s life support systems as mission controllers in Houston conduct a comprehensive checkout of the spacecraft. These milestones will occur as Orion continues an outbound arc toward the high point of its orbit, or apogee.

Upon reaching apogee, around 8 am EDT (12:00 UTC) Thursday, the capsule will fire its thrusters to reshape its orbit to set up for a pivotal trans-lunar injection engine firing Thursday evening. This six-minute burn by Orion’s main engine will send the spacecraft toward the Moon. This all assumes engineers don’t find any significant problems on the first day of the mission.

“On the life support system, the checkout that we get is a critical objective,” said Amit Kshatriya, NASA’s associate administrator. “If it turns out that we don’t get the performance we need after the acceleration and vibe (vibration of launch), we’ll come home. We’re not going to commit to the Moon if we don’t have the performance.”

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Key Takeaways

• Artemis II, NASA’s most daring mission in generations, launches to the Moon

• Liftoff of Artemis II with four astronauts occurred at 6:35 pm EDT (22:35 UTC) on Wednesday

• KENNEDY SPACE CENTER, Fla

• Perched atop the 322-foot-tall (98-meter) Space Launch System rocket, the four astronauts lifted off from NASA’s Kennedy Space Center at 6:35 pm EDT (22:35 UTC)

• Four hydrogen-fueled RS-25 engines and two solid rocket boosters flashed to life to push the nearly 6 million-pound rocket from its moorings at Launch Complex 39B