The Defense Advanced Research Projects Agency (DARPA) is hosting a Proposers Day for the Grainy Day program on June 30, 2025, in Arlington, VA, aimed at informing potential proposers about an upcoming Program Solicitation (PS). The event will focus on innovative solutions for the deployment of unattended sensors from Unmanned Aerial Systems (UAS), particularly in challenging environments, and will encourage participation from experts in aerodynamics, microelectronics, and manufacturing. This initiative is crucial for advancing sensor delivery systems and fostering collaboration among organizations with relevant expertise, while adhering to strict security protocols, including the requirement for participants to possess an active SECRET personnel clearance. Interested parties can contact the BAA Coordinator at GrainyDay@darpa.mil for further information.