From 6,300 applications to eight seats: the math of becoming an astronaut

Space · Published 13 October 2026 Swipe more like this →

In short: The path to space is defined by extreme scarcity. In 2013, NASA faced one of its largest application pools ever, filtering thousands of dreams down to a handful of individuals. Understanding this selection process reveals how the agency balances diverse human expertise against the rigid demands of orbital survival.

The 2013 astronaut class serves as a prime example of NASA's rigorous filtering process. Out of a pool of 6,300 applications—the second largest in the agency's history—only eight candidates were selected. This high level of competition underscores the transition from a military-centric model to a diverse professional pipeline. While the first U.S. astronauts selected in 1959 were all military pilots, modern cohorts include a wide array of backgrounds, including engineers, medical professionals, and even geologists. The agency has identified 23 additional groups of astronauts since the original selection. This evolution reflects a shift toward a broader variety of professional backgrounds.

Once selected, the journey is far from over. Candidates enter an intensive training period that typically lasts about two years before they are even eligible for flight assignments. This training is global and multi-disciplinary, involving technical instruction at the Johnson Space Center and various other international space agencies. The goal is to prepare these individuals for increasingly complex missions, such as maintaining the International Space Station's presence in low Earth orbit and advancing the Artemis missions. The 2013 group began training in August. Their curriculum included specific activities like the Dry Ice Movement on Mars and the Sample Return Robot Challenge.

NASA's selection criteria are dictated by specific mission requirements and the agency's evolving needs. To date, the agency has selected 370 astronaut candidates to fly on various missions. The selection process ensures that while the pool of applicants is vast, the final candidates possess the specific technical competencies required to propel exploration forward into the next decade of space science. The 2024 application cycle concluded on April 16. From that specific pool, the agency chose 10 individuals to become the newest candidates.

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