NASA's Choice of SLS Over SpaceX for Artemis Missions: A Deeper Dive

Why is NASA using the Space Launch System (SLS) instead of SpaceX rockets for the Artemis missions? This question often surfaces in discussions about space exploration, given the stark contrast between the two programs. Below, we delve into the reasons behind NASA's decision and explore the nuances surrounding this choice.

The Congressional Mandate

The primary reason behind NASA's choice to use the SLS is rooted in political mandates rather than technological or performance superiority. As mentioned, there is a Congressional mandate that insists on the use of the SLS. While other rocket options, like SpaceX's Starship or even the Falcon Heavy, would indeed be better alternatives, the political landscape necessitates the use of the SLS to keep certain contractors in the loop. This, in turn, facilitates a steady flow of campaign contributions and political favors.

The pragmatic rationale behind this decision is straightforward: by choosing the SLS, the former shuttle contractors can keep their facilities humming and ensure a continuous source of income. The SLS, despite its similarities to the space shuttle program, is far more expensive and complex. It suffers from cost-plus contracts, which benefit the contractors rather than the taxpayers who provide the funding.

Design and Specifications

Designed and specified in the 1980s, the SLS bears a remarkable resemblance to its predecessor, the space shuttle. Here’s a closer look at the SLS components:

Boosters: The solid boosters for the SLS are the same as those used in the shuttle program. These boosters trace their origins to the 1958 Air Force ballistic missile program, vastly predating the SLS itself.

Core Stage: The core stage of the SLS is a slightly extended version of the shuttle’s external tank. The liquid engines for this core stage are also derived from the shuttle program.

Upper Stage: The upper stage of SLS is based on the Agena program from the 1960s, a well-established and proven design.

The only really new aspects of the SLS are the advanced telemetry and computer systems, as well as the extensive testing procedures. NASA claims to have conducted over 10,000 simulations before the first rollout, but the reality is that the SLS faced multiple delays and complications, including five scrubs due to valve issues.

End of the Space Shuttle Program

The decision to use the SLS for future missions can also be linked to the end of the space shuttle program following the Columbia disaster. President Obama emphasized a shift toward commercial partners for Earth orbit missions, with NASA focusing on deep space exploration, a directive that inadvertently led to the reactivation of the SLS. The space shuttle was designed to be a cost-effective, reusable spacecraft for both crew and cargo, but it fell short of expectations. Instead, it became one of the most expensive and dangerous spacecraft ever flown.

The shuttle program's legacy set a record for the most payload delivered into orbit, but it also came with significant technical and operational challenges. These issues contributed to its eventual demise.

Conclusion

The choice between the SLS and SpaceX rockets for the Artemis missions is a complex mix of political, economic, and technical factors. While the SLS has its strengths and has been improved through technological advancements, the underlying political motivations often take precedence. As we move forward, it's crucial to continue evaluating these choices based on their true potential and value to the goal of human exploration of the Moon and beyond.