The Gateway, a proposed lunar space station designed to orbit the Moon, has seen its launch date pushed back to at least December 2027, with a projected cost estimate of $5.3 billion.

Originally intended to launch in 2022, the Gateway's delays have raised questions about its purpose and usefulness in NASA's ambitious Artemis IV mission, which aims to land humans on the Moon. The current launch target for the Gateway is already three months behind what is required to support Artemis IV.

The GAO report outlines a complex sequence of events that need to occur for the Gateway to be involved in the Artemis IV mission. This includes the launch of initial segments of the Gateway, a power and propulsion module, and a habitation module to a halo orbit around the Moon. Additionally, supplies would be delivered using a SpaceX Dragon XL vehicle, and multiple SpaceX Starships would fuel a Lunar Starship that would dock with the Gateway. A NASA Space Launch System rocket carrying astronauts would also be launched, along with another Gateway module. The report recognizes the coordination challenges and notes that this mission will be the first launch of an upgraded version of the Space Launch System rocket.

The report also flags significant technical concerns for the Gateway program. One notable issue revolves around a defective network chip responsible for communication throughout the lunar space station. Failure of this chip could lead to a host of problems onboard the Gateway, including unexpected restarts of flight computers, potentially resulting in a loss of control. Program officials expressed concerns that more defects might be identified with the communication network.

Another technical risk highlighted in the report is the "stack controllability" problem. Due to the substantial mass difference between SpaceX's Lunar Starship and the Gateway, the Gateway's power and propulsion element (PPE) will struggle to maintain the proper orientation of the stack when the two are docked. This discrepancy raises concerns over cost growth and schedule delays, as design changes might be necessary to address this issue.

Furthermore, the report casts doubt on the Gateway's utility for future Mars missions. The "stack controllability" challenge poses a significant constraint for hosting large Mars transit vehicles, while the planned 15-year lifetime of the Gateway may fall short of sustaining Mars missions, especially considering crewed missions to Mars are expected to commence around 2042.

Overall, the GAO report suggests that the Lunar Gateway program is facing substantial setbacks and may have limited usefulness for lunar and Mars landings. The complexity of the mission, along with the technical challenges, are aligning with NASA's efforts to establish a lunar surface program, but the space agency remains committed to pushing forward despite the obstacles.