NASA's deputy administrator, Pam Melroy, confirms near-unanimous support for its low Earth orbit microgravity strategy. This strategy advocates for continuous human presence in orbit during the transition to commercial space stations, a concept termed "continuous heartbeat."
The final version of the LEO Microgravity Strategy, released December 16, supports maintaining a continuous human presence in LEO as NASA transitions from the International Space Station (ISS) to commercial alternatives. This decision followed deliberations between "continuous heartbeat" and "continuous capability," the latter allowing for gaps in crewed orbital presence. Melroy clarified that earlier uncertainty expressed at the International Astronautical Congress (IAC) in October was intentional, aimed at eliciting broader feedback. "I did that on purpose because we needed people to come back and tell us what they thought,” she stated. “If you were sitting on the sidelines with an opinion, it flushed everybody out.”
By the IAC, internal consensus had formed around "continuous heartbeat," driven by the need for long-duration flights to prepare for Mars missions and bolster commercial providers' business cases. International partners and government agencies overwhelmingly favored "continuous heartbeat," with industry support described as "nearly unanimous."
Concerns among some companies centered on NASA's transition speed from the ISS to commercial stations and the challenges of developing continuously habitable stations. The strategy will now guide the request for proposals (RFP) for phase two of the Commercial LEO Development (CLD) program, aiming to select companies to certify their stations and procure services. A draft RFP is anticipated in June 2024, with awards in mid-2026. Melroy acknowledged the tight schedule for achieving at least one operational commercial station by 2030, the ISS deorbiting target, stating, “It’s tight.”
Feedback on the strategy's draft refined the science objectives, emphasizing continued progress from ISS research and incorporating a goal of "rapid" LEO science via iterative research capabilities. The approach mirrors NASA's Moon to Mars Architecture, and Melroy suggests its applicability to other agency initiatives within the NASA 2040 framework. She emphasized the importance of aligning multiple strategies for improved agency efficiency. Melroy will be leaving NASA at the end of the Biden administration.