After Artemis 1, it will take NASA 2 years to send astronauts to the moon. Why so long?

Orion's successful splashdown Sunday afternoon (Dec. 11) returned some critical components needed for NASA's Artemis 2 moon mission, which is scheduled to launch 2024 — but it may be tough for the agency to hit that target. 

Artemis 1, NASA's first in a series of missions designed to return humanity to the lunar surface, is now complete. On Sunday at 12:40 p.m. EST (1740 GMT), an uncrewed Orion spacecraft splashed down in the Pacific Ocean off the coast of Baja California, wrapping up its 25.5-day mission to lunar orbit and back.

Artemis 1 launched from NASA's Kennedy Space Center, in Florida on Nov. 16 on the debut mission of the agency's huge new Space Launch System (SLS) rocket. Though the premiere of SLS was delayed several times beyond its originally targeted launch date of 2017, the rocket performed perfectly in delivering the Orion spacecraft to Earth orbit.

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With Artemis 1 now in the books, public focus is quickly shifting to the program's next phase: crewed flight. But that can't happen until several pieces fall into place — namely, a completely assembled spacecraft and launch vehicle. While NASA engineers and contractors have been busy constructing various elements of the SLS that will launch Artemis 2, key components for the mission's Orion capsule are being reused from Artemis 1 and must first undergo a series of post-flight validation tests before being installed on the new spacecraft. And that's going to take some time. 

NASA's decision to reuse some of Orion's flight hardware was made at a time when Artemis 1 was still known as Exploration Mission-1 (EM-1), and the schedule for SLS placed a full three years between the first two launches. A 2017 NASA blog post mentions recycling Orion's hardware, stating, "NASA is reusing avionics boxes from the Orion EM-1 crew module for the next flight. Avionics and electrical systems provide the 'nervous system' of launch vehicles and spacecraft, linking diverse systems into a functioning whole."

Artemis 2, or Exploration Mission 2 (EM-2), as it was called at the time, was originally slated to fly on an SLS Block 1B rocket, a larger upgraded version of the SLS used for Artemis 1, which replaces the vehicle's Interim Cryogenic Propulsion Stage (ICPS) with the more powerful Exploration Upper Stage (EUS). The three-year gap between EM-1 and EM-2 was meant to allow time for upgrades to the SLS mobile launch platform (MLP) to support the taller SLS Block 1B. Comparatively, NASA's estimated timeline to remove, refurbish and reinstall Orion's avionics hardware was not expected to affect the launch schedule.

By 2018, however, NASA funding appropriations from Congress and agency attempts to quicken SLS' launch cadence led to the decision to construct a second MLP to support the rocket's larger configurations. This move abandoned plans to upgrade the existing MLP, leaving it capable of only launching the SLS Block 1. In turn, the first three flights of SLS were changed to fly in the Block 1 configuration. While this shortened the lull between missions, it also ended up putting a magnifying glass over the decision to reuse some of Orion's avionics. 

Related: Artemis 1 moon rocket, NASA's most powerful ever, aced its debut launch

According to a November 2022 report from the NASA Office of Inspector General (OIG), "[NASA's] Exploration Systems Development Mission Directorate considers the non-core avionics reuse to be the primary critical path for the Artemis 2 mission, with total preparation work between missions to take about 27 months." "Critical path" the report explains, "is the sequence of tasks that determines the minimum duration of time needed to complete a project." In short, Artemis 2 can only launch as soon as the most time-consuming task on engineers' checklists is complete. That task will likely be the processing and reinstallation of Artemis 1 hardware.

"Non-core," in this case, refers to a subset of hardware aboard Orion, as opposed to "core" avionics, and helps differentiate between some of what will and won't be reused from the spacecraft's first flight. "There are connectors that can be demated," explained one NASA engineer to Space.com. So, the avionics boxes' removal and installation on the Artemis 2 Orion capsule will be more akin to unplugging your home office to transfer from one room to another than to ripping up your drywall to rewire your house. But before those components can be installed in the Orion for Artemis 2, they need to be tested.

With Artemis 1 complete and Orion back on Earth, technicians will now study the spacecraft and its systems to determine how well it performed in flight. Many on-board experiments for Artemis 1 focused on radiation exposure, including the mannequins Helga and Zohar as part of the Matroshka AstroRad Radiation Experiment (MARE). Nearly a dozen other active and passive dosimeters are scattered throughout the capsule as well.

Radiation in space can have significant impacts on flight systems as well as biological ones. Therefore, extensive efforts are taken when designing a spacecraft to protect crews and hardware from exposure. Aboard the International Space Station (ISS), NASA has studied the effects of microgravity and radiation on the human body for more than 20 years. However, exposure levels in deep space and around the moon are much higher than in low Earth orbit (LEO), where the ISS operates. 

On its maiden voyage around the moon, Orion flew farther from Earth than any spacecraft designed to carry humans, reaching a distance of 268,563 miles (432,210 kilometers) on Nov. 28, beating the record set by the Apollo 13 mission by nearly 20,000 miles (32,186 km). Barring any off-nominal findings from the Artemis 1 flight data, NASA plans to fly four astronauts aboard Artemis 2 on a trajectory around the moon, reaching a maximum altitude of 5,523 miles (8,889 km) above the Moon's surface, according to the European Space Agency (ESA). That would place them second behind the Apollo 13 astronauts, who got farther from Earth while troubleshooting a near-disaster that prevented them from landing on the moon as planned. 

Unlike Artemis 1, the crew aboard Orion on Artemis 2 won't technically enter lunar orbit. For Orion's first excursion to the moon, the SLS core stage launched the spacecraft and the ICPS into Earth orbit, and the ICPS performed a translunar injection burn to put Orion on course for the moon. There, Orion's service module placed the spacecraft in a distant retrograde orbit (DRO), where it remained from Nov. 25 to Dec. 1. On Dec. 5, the capsule headed back toward Earth via a long engine burn conducted during a close lunar flyby. In total, the Artemis 1 mission lasted about 25.5 days. 

The Artemis 2 crew won't get to enjoy their mission for quite as long; Orion's second lunar expedition is scheduled to last just over 10 days. After completing some extended laps around the Earth, the flight path for Artemis 2 puts Orion on a path to return from a lunar flyby without slowing the spacecraft's trajectory enough to maintain a stable lunar orbit.

Related: Facts about NASA's Artemis program

"In terms of the mission length for Artemis 2, we're looking at a 10.5-day crewed flight test," Artemis 1 mission manager Mike Sarafin explained in a briefing on Nov. 28. "Four astronauts will fly a one-day, highly elliptical orbit to basically shake down the life support system and perform a proximity operations demonstration with the upper stage before it is separated at a far distance from Orion. And then at the end of that one-day high Earth orbit, Orion will essentially perform a mission completion maneuver and use the service module to perform the translunar injection maneuver and put itself on a free-return trajectory — about 4.5 days out [to the moon] and about 4.5 days back. So it'll be a little over 10 days."

Currently, NASA is targeting sometime in 2024 for the launch of Artemis 2. However, if the clock to transfer Orion's avionics boxes started the moment of splashdown, the 27 months estimated by NASA's OIG to complete the task already pushes the agency's 2024 goal into 2025. The next mission after that, Artemis 3, is not dependent on any of Artemis 2's flight hardware. It is dependent, however, on a host of other milestones, making it unlikely that the mission, currently slated for 2025, will launch on time either. 

Artemis 3 is designed to land crews on the moon's surface — specifically, the lunar south polar region. This will require a landing system for ferrying crews to and from the lunar surface (SpaceX's huge new Starship vehicle) and new spacesuits for astronauts to wear while performing moonwalks or cislunar extravehicular activities (EVAs). For all of these things to be ready in time for a 2025 moon landing would be a monumental feat for NASA and its partners.

NASA also plans to build a small moon-orbiting space station called Gateway as part of the Artemis program. Gateway's timely construction hinges on a number of factors falling into place, not least of which is a rocket powerful enough to launch the station's various modules, and also a launch tower to support that rocket. NASA selected SpaceX's Falcon Heavy to launch the first Gateway components in late 2024 but has stated the need for the SLS Block 1B and other upgraded variations to launch additional station modules and other habitation hardware needed for long-term lunar stays. 

And the second MLP, designated ML-2, required to support those future SLS rockets hasn't even begun construction yet. After Congress' budget appropriations for a second launch tower, NASA selected Bechtel as the project's primary contractor. Now, years later, the undertaking is still in the design and planning phases and will likely cost 2.5 times higher than originally projected, totaling nearly $1 billion and counting. 

A NASA OIG report from June 2022 indicates that ML-2 will likely not be ready for operational use until the end of 2026, placing the earliest possible launch for an SLS Block 1B sometime in 2027. The report reads, in part, "as of May 2022, design work on the ML-2 was still incomplete, and Bechtel officials do not expect construction to begin until the first quarter of fiscal year 2023 at the earliest. To complete contract requirements and deliver an operational ML-2, Bechtel estimates it will need an additional $577.1 million, bringing the structure's total projected cost to $960.1 million coupled with an October 2025 rather than March 2023 delivery date. We expect further cost increases as inevitable technical challenges arise when ML-2 construction begins."

Related: NASA rolls Artemis 1's huge launch tower off pad for repairs, upgrades (photos)

Now, a successful lunar landing on Artemis 3 may not necessarily hinge on whether or not any components of Gateway are in place in time to support the mission. In 2021, NASA awarded SpaceX the agency's Human Landing System (HLS) contract to build a lunar lander for the Artemis program, based on the company's Starship spacecraft currently still under development. It's worth noting that, once operational, SpaceX's Super Heavy rocket required to launch Starship will be more powerful than SLS, cheaper and faster to produce, and will be reusable. 

With some refueling along the way, Starship is also expected to be capable of reaching the moon, then return to Earth following a lunar landing, eliminating the need to transfer crew or cargo between vehicles along the way. However, NASA's current framework for Artemis 3 still outlines a crewed Orion launch and an HLS rendezvous in lunar orbit before landing astronauts on the lunar surface. The first orbital launch attempt for SpaceX's Starship is expected early in 2023, but it's unclear when the giant vehicle will be fully operational.

Even if Starship is ready by 2025, the spacesuits astronauts need to traverse the lunar surface may not be. Indeed, NASA has a bit of a spacesuit problem. The spacesuits currently used for ISS EVAs are remnants of the 1980s and '90s, when NASA contractor ILC Dover supplied 18 EVA suits for use on the space shuttle and eventually the space station. Of those, 11 remain, and they are split between the ISS and NASA's testing facility at the Johnson Space Center. 

After the space shuttle program was canceled in 2011, ILC Dover provided the remaining suits with some major upgrades, which allowed them to be stored on orbit aboard the ISS long-term, but a NASA OIG report from 2017 paints a bleak picture for a spacesuit development timeline favorable to the ISS or Artemis. The report raises the concern that current suit inventory may be inadequate to last through the space station's life expectancy. "NASA will be challenged to continue to support ISS needs with the current fleet of EMUs [(extravehicular mobility units)] through 2024, a challenge that will escalate significantly if station operations are extended to 2028," the report reads. NASA officials have repeatedly stated throughout the past year their hope to fly the ISS until at least 2030.

An entirely different spacesuit is needed for the Artemis missions, however. A 2018 NASA OIG report points out that even new EVA suits for the ISS wouldn't "offer the mobility, durability, or functionality planetary or cislunar missions will require." The report also stresses the need for NASA to test new EVA suits in microgravity or "accept higher levels of risk during future exploration missions, potentially impacting astronaut health and safety as well as mission success."

At the time of that report, the schedule for ISS technology demonstrations projected new EVA suit tests to take place between 2024 and 2025. For Artemis, the only opportunity to test a spacesuit in lunar orbit before an Artemis 3 landing attempt will be during Artemis 2, and another OIG report, this one from last year, cast further skepticism on NASA's ability to keep to the agency's stated timeline. NASA's Exploration Extravehicular Mobility Units (xEMU),  as the suits are known, spent a slow decade in development, and burned through over a billion dollars, the report indicates.

"The Agency faces significant challenges in meeting this goal," the report reads. "This schedule includes approximately a 20-month delay in delivery for the planned design, verification, and testing suit, two qualification suits, an ISS Demo suit, and two lunar flight suits. These delays — attributable to funding shortfalls, COVID-19 impacts, and technical challenges — have left no schedule margin for delivery of the two flight-ready xEMUs. Given the integration requirements, the suits would not be ready for flight until April 2025 at the earliest."

NASA took the OIG report's findings seriously and made the decision to outsource the efforts in order to expedite suit readiness for both the ISS and Artemis. In June of this year, NASA tapped companies Axiom Space and Collins Aerospace (working with ILC Dover) to develop new spacesuits, and in September selected Axiom to provide the suits astronauts will wear on the surface of the moon. Axiom is also seeking to install its own module on the ISS by 2024, to serve as the core of a new private space station, and operated Ax-1 in April of this year, the first of a handful of planned privately crewed missions to the ISS. So it is feasible the company could test its spacesuit in the microgravity environment available in LEO, if not on Artemis 2.

Publicly, NASA is still voicing confidence in a 2024 launch for Artemis 2, but with the agency's own internal documents suggesting otherwise, it may only be a matter of time before that messaging is changed. So, for now, everyone who was awestruck by the sight of Artemis 1 leaving the planet in a blaze of light will have to practice patience while waiting for the next SLS to light up the sky.

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