Booster Delivery Marks NASA Artemis II Moon Mission Milestone

Northrop Grumman on Tuesday delivered 10 booster motor segments, which the space agency will use for its Artemis II mission, to Kennedy Space Center in Florida from its manufacturing plant in Utah. The delivery should keep NASA on track to launch the first crewed Artemis mission, which is expected to send four astronauts on a jaunt around the moon in November 2024—so long as prelaunch activities continue to go as planned.

The 10 segments built by Northrop will form twin solid rocket boosters designed to power NASA’s Space Launch System (SLS) super-heavy lift rocket. In preparation for Artemis II, the boosters will be the first element of the SLS to be stacked on the mobile launch platform.

NASA says the SLS “is the only rocket that can send [NASA’s Orion deep exploration spacecraft], astronauts, and supplies to the moon in a single mission.” It has a greater payload mass, volume, and departure energy than any other single rocket and made its debut on the successful Artemis I mission, the program’s first, uncrewed flight, last November.

According to Northrop, the twin boosters will provide some 7.2 million pounds of thrust at launch—more than three-quarters of the total power generated by the SLS. They’ll help Orion reach 24,500 mph on its way to the moon. Last week, the agency and its contractor completed a subscale booster thrust test to validate the technology.

“The arrival of the SLS solid rocket booster motor segments is an important turning point as NASA and our Artemis partners begin readying for stacking and launch preparations for Artemis II,” said Amit Kshatriya, deputy associate administrator for the Moon to Mars program office at NASA headquarters. “Fully stacked, these boosters for NASA’s SLS rocket are the largest, most powerful ever built for spaceflight and will help send the first astronauts around the moon [for the first time] in more than 50 years.”

Now, teams with NASA’s Exploration Ground Systems (EGS) program are processing each segment before integrating them at Kennedy’s Vehicle Assembly Building. They’ll then inspect the motor, forward, and aft assemblies of the twin boosters, rotate them to a vertical position, and move the segments one at a time for stacking, forming a pair of 17-story-tall boosters.

After the boosters are stacked, engineers will then integrate the SLS’s 212-foot core stage, for which Boeing is the lead contractor. All four RS-25 engines for the core were structurally joined this week at NASA’s Michoud Assembly Facility in New Orleans. The engines, built by California-based Aerojet Rocketdyne, will provide an additional 2 million pounds of thrust at launch

Combined, the boosters and engines will deliver 8.8 million pounds of thrust. That number mirrors SLS data from Artemis I, which sent an uncrewed Orion capsule into orbit 40,000 miles beyond the moon. Figures collected from the 1.4 million-mile journey showed the 312-foot-tall rocket “met or exceeded all performance expectations.”

As NASA works toward stacking the SLS, EGS teams are simultaneously conducting ground systems tests, the first of which took place last week.

Northrop’s delivery of the booster motor segments, as well as the integration of the RS-25 engines to the core stage, keeps NASA in line with a rough timeline shared with Ars Technica last month by Jeremy Parsons, deputy manager of the EGS program.

By Parsons’ estimate, the SLS core stage will ship to Kennedy from NASA’s New Orleans assembly plant next month. Stacking of the twin boosters is expected to begin in February, followed by core stage stacking in April. Orion will also be fueled that month and is expected to be stacked sometime in mid-2024. But the timeline gets a bit fuzzy by then, and Ars Technica reported Artemis II’s launch date “almost certainly will slip two or three years.”

The goal of Artemis II is to test Orion and SLS systems before Artemis III returns U.S. and Canadian astronauts to the moon. Going by Parsons’ timeline, the mission is expected to launch nearly two years after Artemis I, which damaged the mobile launch pad more severely than anticipated.

However, the massive structure returned to Launch Complex 39B at Kennedy in August, and excitement is starting to build for the marquee mission.

Artemis II crewmembers—who are slated to also fly on Artemis III—were revealed in April, representing the first woman and person of color to land on the moon. Mission specialist Christian Koch and Artemis II pilot Victor Glover, who is Black, will gain those respective distinctions. They’ll be joined by NASA astronaut and Artemis II commander Reid Wiseman, as well as mission specialist Jeremy Hanson of the Canadian Space Agency.

Their mission will last around 10 days, sending the four explorers around the moon and paving the way for the first crewed lunar landing since the Apollo program. Northrop has also completed motor segments for Artemis III and is building more for future missions.

The landmark journey is planned for 2025. But a delay to its precursor or snags in the delivery of key hardware could push it back. Jim Free, associate administrator for NASA’s Exploration Systems Development Mission Directorate (ESDMD), remarked in June that delays to the lunar lander variant of SpaceX’s Starship will “probably” cause the timeline to slip to 2026. SpaceX is embroiled in an FAA mishap investigation that has set back Starship’s orbital test flight program.

Beyond Artemis III, NASA hopes to launch crewed lunar missions once per year with an initial focus on establishing “surface capabilities” for potential long-term human settlements on the rocky satellite. Artemis missions will also support the buildout of Gateway, a planned orbital outpost around the moon and possible staging point for future deep space exploration.

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