Full draft NF5 AO is now available:

https://go.nasa.gov/NF5DraftAO" target="_blank"> https://go.nasa.gov/NF5DraftAO

Interestingly, there's an incentive to collaborate on proposals (and the selected mission) with ESA:

"NASA and the European Space Agency (ESA) have formalized a partnership for the NF5 mission that provides an optional contribution(s). The contribution(s) may include hardware procured by ESA from European vendors and/or other services, such as ground segment support, to be considered under ESA responsibility."

In the ESA system, instruments are paid for by the individual nations; presumably ESA is offering to collaborate under the assumption that there also would be instrument(s) from European nations.

Other key points:

Proposals prepared in response to this AO must describe an investigation that addresses at least one out of any of the six mission themes described below. These themes, listed without priority, are:
• Comet Surface Sample Return
• Io Observer
• Lunar Geophysical Network
• Lunar South Pole-Aitken Basin Sample Return
• Ocean Worlds (only Enceladus), and
• Saturn Probe.

The following schedule describes the planned major milestones for this AO:
AO Release Date ...........................................November 2023 (target)
Preproposal Conference .........................................................AO Release + ~3 weeks (target)
Mandatory Notice of Intent to Propose Deadline
at 11:59 p.m. Eastern Time ....................................................AO Release + 4-6 weeks (target)
Electronic Proposal Submittal Deadline
at 11:59 p.m. Eastern Time ....................................................April 2024 (target)
Letters of Commitment Due (with Proposal).........................April 2024 (target)
Deadline for Augmented Submission via the NASA Box service
at 4:30 p.m. Eastern Time ......................................................April 2024 (target)
Step-1 Selections Announced (target) ...................................December 2024 (target)
Initiate Phase A Concept Studies (target) ..............................January 2025 (target)
Phase A Concept Study Reports Due (target) ........................January 2026 (target)
Down-selection of Investigation for Flight (target) ...............…October 2026
AO-Required Launch Readiness Date ...................................January 1, 2031, to December 31, 2034