To the Moon: NASA Lays Out Blueprint for Artemis I Lunar Launch This Month

Monisha Ravisetti Former Science Writer
Monisha Ravisetti was a science writer at CNET. She covered climate change, space rockets, mathematical puzzles, dinosaur bones, black holes, supernovas, and sometimes, the drama of philosophical thought experiments. Previously, she was a science reporter with a startup publication called The Academic Times, and before that, was an immunology researcher at Weill Cornell Medical Center in New York. She graduated from New York University in 2018 with a B.A. in philosophy, physics and chemistry. When she's not at her desk, she's trying (and failing) to raise her online chess rating. Her favorite movies are Dunkirk and Marcel the Shell with Shoes On.
Monisha Ravisetti
5 min read
NASA's orange Artemis I rocket is seen atop the flame trench in the daytime.

NASA's Space Launch System rocket, with the Orion spacecraft aboard, sits atop the mobile launcher as it is rolled up the ramp at Launch Pad 39B, on Aug. 17 at Kennedy Space Center in Florida.

NASA/Joel Kowsky

What's happening

NASA is targeting Aug. 29 for its Artemis I moon rocket launch day.

Why it matters

Artemis is NASA's ambitious space exploration endeavor to bring humans back to the moon, and eventually, to Mars.

What's next

There are still some testing procedures to carry out, but we now have a pretty good idea of the complicated liftoff sequence.

NASA's Artemis I moon mission is closer than ever to liftoff. After a 10-hour journey, the Space Launch System megarocket reached the Florida launchpad on Wednesday. All eyes are now on Aug. 29 -- the first date on a list of three possible windows for liftoff.

"We've basically got a date with the range on the 29th of August," Mike Sarafin, Artemis I mission manager, said in a press conference earlier this month. "If we're unable to launch for whatever reason -- weather, technical incursion in the range, that kind of stuff -- our backup date is no earlier than Sept. 2."

The agency still has several important tests to conduct prior to the big day, to make sure the mission's massive rocket, dubbed the Space Launch System, or SLS, is in tip-top shape for a trying journey ahead. This means even though Artemis I has made significant progress toward liftoff, there's still room for error. 

NASA's Artemis I moon rocket is seen from a distance, being transported to the VAB on a car-less, double-streeted road.

Here's what the 32-story-tall mega moon rocket looks like while being rolled out to launchpad 39B.

Kim Shiflett/NASA

Before its 10-hour journey that concluded at 7:30 a.m. ET/4:30 a.m. PT Wednesday, the spacecraft had waited inside the Vehicle Assembly Building at Kennedy Space Center since late June. During that time, it underwent more servicing after completion of its wet dress rehearsal -- a preflight testing sequence that involves filling the rocket tank with fuel. That wet dress rehearsal was a painstaking process in itself. It took four tries, and alongside NASA's announcement of its completion, there was a slight caveat. The agency reported a hydrogen leak, yet assured the public that it wouldn't affect the road to launch. 

It's been an absolute roller coaster ride for Artemis so far. Even SLS costs are adding up to a level far beyond projections made during the project's genesis. But if everything goes as planned, here's what to expect on launch day. 

NASA's Artemis I moon mission launch sequence

The basic anatomy of the Artemis I contraption includes the SLS rocket, a giant vehicle adorned with NASA's iconic logo, and the Orion spacecraft, which contains payloads meant for science exploration. The SLS is topped with Orion, like a pencil with a point. 

Against a midnight blue sky, a full moon is visible toward the top left of the image and NASA's orange Artemis I rocket and Orion spacecraft set up in the foreground.

A full moon is in view from Launch Complex 39B at NASA's Kennedy Space Center in Florida in June. 

Cory Huston/NASA

Within Orion, there's a party. 

The things it contains range from Amazon Alexa and TV character Shaun the Sheep to CubeSats and human stand-ins

"We'll be flying some mannequins and some torsos that have simulated human tissue and organs, that are looking at radiation protection, radiation environment, the acceleration of the vehicle and how that affects the human body," Melissa Jones, Artemis I recovery director, said in a press conference on Aug. 5. This bit is especially crucial because even though Artemis I won't have a human crew, data it collects while traveling to the moon and back will inform later Artemis missions with astronauts aboard. 

Now that the SLS rocket is rolled out to the launchpad and positioned over what's called a flame trench, NASA will proceed with activities like loading it with cryogenic fuel and pumping oxidizer into its core and upper stages. Then, "when all systems are go," Sarafin said, "Artemis I will begin."

Team SLS is up first.

After countdown, the SLS will ascend through Earth's atmosphere. In two minutes, all its solid propellant will be consumed and the rocket's boosters will be jettisoned. In eight minutes, all its liquid fuel will be consumed and the rocket's core stage will be jettisoned. Then, for about the next 18 minutes, Orion and the rocket's upper stage will take a lap around our planet by themselves. Orion will then take about 12 minutes to deploy its solar arrays and get off battery power. 

This diagram shows the stages at which the SLS rocket's stages will be jettisoned and Orion will travel during ascent.
Enlarge Image
This diagram shows the stages at which the SLS rocket's stages will be jettisoned and Orion will travel during ascent.

A diagram showing what Artemis I's ascent will look like. 

Screenshot by Monisha Ravisetti/NASA

"Our final maneuver by the upper stage will be the translunar injection orbit maneuver that will be approximately an hour and 20, 30 minutes into the flight," Judd Frieling, Artemis I ascent and entry flight director, said during the Aug. 5 conference. "That will be about an 18-minute burn and will send us all the way to the moon, approximately a quarter million miles away." At that point, as Sarafin puts it, the rocket has done its job and Orion is en route to the moon.

Next, the Orion team steps in. 

"There's really no time to catch our breath," Rick LaBrode, lead Artemis I flight director, said during the Aug. 5 press conference. Most of Orion's trajectory includes lots (and lots) of precise maneuvering that will take it along a complex path, as seen below.

A diagram showing how Orion will fly to the moon, around the moon and back. Several gravity assists are present during the journey and some checkpoints are outlined where translunar injections and departures will occur.
Enlarge Image
A diagram showing how Orion will fly to the moon, around the moon and back. Several gravity assists are present during the journey and some checkpoints are outlined where translunar injections and departures will occur.

Orion's trajectory around the moon and back is outlined here. Along the way, 10 CubeSats will be deployed. 

Screenshot by Monisha Ravisetti/NASA

As the spacecraft approaches the lunar surface, getting as close as just 60 miles above ground, per the team, it'll begin conducting science experiments to test lunar gravity, radiation dangers and even take beautiful pictures, like a re-creation of 1968's Earthrise, and much more. 

Along the way, the Orion team will also be deploying a handful of 10 CubeSats from the hatch, which are like little boxy satellite systems. "We have no interaction with those secondary payloads. The only thing we're concerned with is their initial trajectories where they're being deployed," LaBrode said.

On wrapping up its eventful excursion, Orion will return to our planet and get set for splashdown off the coast of San Diego. 


Earthrise, taken during the first crewed voyage to the moon, Apollo 8.

Bill Anders/NASA

"Once we splash down, we'll leave the vehicle powered for about two hours," Frieling said. "We're going to do some thermal testing to make sure we have adequate cooling for astronauts when we eventually have them on board and they're waiting to be picked up by recovery crews."

Pick up Orion, extract the data, and the mission is complete for Artemis I. Time to exhale. 

But that's not nearly the end of NASA's lunar dream. 

Down the line, Artemis I will lead to Artemis II, which will send humans into lunar orbit. And that will lead to Artemis III, which will land humans on the surface of the moon. Then, Artemis III leads to the first woman and person of color landing on the glowing rock, which then paves the way for the agency's ultimate goal: trekking on Mars and building red planet science laboratories.

"When we think about Artemis, we focus a lot on the moon," Reid Wiseman, chief astronaut at NASA's Johnson Space Center, said on Aug. 5. "But I just want everybody in the room and everybody watching to remember our sights are not set on the moon. Our sights are set clearly on Mars."