Four days after astronauts flew around the moon for the first time in a half-century, ground crews across Southern California are making final preparations for their high-energy reentry and splashdown off the coast of San Diego, expected around 5 p.m. Pacific time Friday.

Southern Californians likely won’t be able to see reentry or splashdown in person, NASA officials said. However, NASA will livestream the event. Here’s what you should know:

The four members of the Artemis II crew will rip through the atmosphere at roughly 24,000 mph — over 30 times the speed of sound — agitating the air around the capsule into a fireball roughly half as hot as the surface of the sun.

NASA will use a new, more direct reentry technique, after the heat shield for the 2022 Artemis I test mission, which had no one aboard, unexpectedly chipped in more than 100 spots.

Artemis II pilot and SoCal native Victor Glover has been thinking about reentry since he was assigned the mission in 2023. When Glover, still in space, was asked Wednesday evening about the moments from this mission he’ll carry with him for the rest of his life, he joked: “We’ve still got two more days, and riding a fireball through the atmosphere is profound as well.”

How to watch

“The path we’re coming in, I don’t expect it to be visible for folks in California,” Artemis II Lead Flight Director Jeff Radigan said at a news conference Thursday.

Nonetheless, San Diegans hoping to catch a glimpse can look west over the Pacific around 5 p.m. for the best chance to see the Orion capsule, which would appear as a fast and bright streak low in the sky.

For anyone hoping to get a closer view via boat, “I would caution folks, please avoid the area,” Radigan said. “There’s a lot of debris that comes down, and we work with our recovery forces in order to ensure that it doesn’t hit them. But of course we don’t want it to hit anyone else.”

The last time NASA astronauts splashed down in a brand-new vehicle, lookie-loos caused some serious safety concerns, including potentially exposing boaters to toxic chemicals and delaying the recovery of astronauts if there was an emergency.

For the best, up-close views, NASA is livestreaming reentry and splashdown on YouTube, Netflix and HBO Max. The Times will also carry live views of the dynamic return to Earth on latimes.com.

The San Diego Air & Space Museum will also host a family-friendly viewing party.

The plan for reentry

NASA expects reentry to begin at approximately 4:53 p.m. Pacific time. (Yes, NASA “approximations” are that precise.)

When it does, the agency expects to lose communication for about six minutes as the Orion capsule holding the astronauts is enveloped in a fireball.

During all this, a team of NASA and Department of Defense test pilots will chase the capsule in airplanes as researchers in the back point telescopes and sensors at its heat shield. NASA hopes to use this data to better understand how that protection holds up under the agency’s new reentry technique.

Around 5:03 p.m., two small parachutes will deploy, slowing the craft down to about 300 mph. A minute later, much larger chutes will deploy, slowing the capsule to about 17 mph. Three minutes later, around 5:07 p.m., the capsule will splash down in the Pacific Ocean.

A team of Navy divers will then help the astronauts out of the capsule, and Navy helicopters will swoop in to recover them.

The helicopters will take the astronauts to the U.S.S. John P. Murtha, a 680-foot-long, 25,000-ton Navy transport dock warship, for an immediate medical evaluation. Navy divers will then secure the capsule and guide it to the Murtha’s deck.

Then they’ll bring the astronauts back ashore as the Murtha slowly returns to San Diego. The astronauts will fly to Houston to NASA’s Johnson Space Center to reunite with their families.

Boots on the moon and someday Mars

The Artemis program ultimately aims to land humans back on the moon. NASA eventually hopes to establish a lunar base that will serve as the testing grounds for future missions to Mars.

This mission primarily aimed to test the capsule’s life support systems to help create a smoother ride for future crews that will have to deal with the headaches of actually landing on the moon. This included troubleshooting the capsule’s space toilet (multiple times), piloting the spacecraft by hand, and testing procedures such as sheltering from solar radiation in the cargo locker.

NASA plans to launch Artemis III, a mission in Earth’s orbit to test docking the Orion spacecraft with SpaceX’s and Blue Origin’s lunar landers, in 2027. It aspires to launch Artemis IV, which would put humans on the surface of the moon, in 2028.

Heavier rain is expected to fall across Los Angeles this weekend, bringing wetter weather and a chance for thunderstorms after spring kicked into full bloom.

“This is when the weather gets a little more wild, technically, because we’re starting to see some more differential heating on the Earth,” said Todd Hall, a meteorologist at the National Weather Service.

Parts of Los Angeles will probably see rain after 11 p.m. Saturday, according to a forecast from the National Weather Service. Scattered showers are anticipated on Sunday afternoon before 2, and there is a potential for thunderstorms in some parts of the city.

There’s a 15% to 25% chance of thunderstorms, according to the forecast discussion from the NWS Los Angeles on Saturday. “Any thunderstorms that develop will likely produce brief heavy rain, gusty outflow winds, small hail and potentially waterspouts or weak, short-lived, tornadoes,” the NWS said.

A ridge of high pressure has already moved east, and now a storm system is arriving in the area.

There’s a chance that the storm system will linger across parts of Los Angeles through Monday, Hall said. Snow levels are expected to drop at high elevations, but some places, such as the northern Ventura County mountains, could have wet snow, so drivers should be cautious.

Gusty winds are expected in portions of the Mojave Desert as well.

“Just like in the ocean, we have waves. The atmosphere behaves the same way,” Hall said.

The total rainfall through Sunday night is anticipated to be between 0.50 and 1.50 inches. On average across L.A., temperatures on Sunday are expected to reach a high of 65 degrees — a full 26 degrees lower than the high recorded a week ago.

Dry and warm weather is expected to return after Monday. Temperatures are forecast to climb to more than 75 degrees later in the week and reach nearly 80 degrees next Saturday.

Heavier rain — including some thunderstorms — is expected in other parts of California such as the counties of San Luis Obispo, Santa Barbara and Ventura, the National Weather Service Los Angeles said Saturday afternoon on X.

Wind gusts north of Point Conception in Santa Barbara County could come with risks such as downed trees or powerlines. Major flooding and debris flows are unlikely, the social media post said.

Up north, the San Francisco Bay Area has already been experiencing the severe weather. Heavy rain hammered the region Saturday, and wind gusts were expected to reach up to 28 mph. The National Weather Service was advising people to allow extra time for travel because of the slippery roads.

In Southern California, the National Weather Service suggested that people be ready to adjust plans and monitor the situation.