Amendment 1

SPECIAL NOTICE DARPA-SN-27-03

Cattle Run Proposers Day
EVENT DATE: 10 November 2026

REGISTRATION DEADLINE: 4 November 2026, 12:00pm EST

REGISTRATION WEBSITE: https://cvent.me/BVOW3V
TECHNICAL POC: Mr. Steven Chambers, STO Program Manager E-MAIL: DARPA‐SN‐[email protected]

PROPOSERS DAY:

DARPA is hosting a Proposers Day in support of DARPA-SN-27-03 Cattle Run program on Tuesday, November 10, 2026, at the DARPA Conference Center (675 North Randolph Street, Arlington, VA 22203) from 8:00am to 5:00pm EST. The purpose of this conference is to provide information on the Cattle Run program, promote additional discussion on this topic, address questions from potential proposers, and provide a forum for potential proposers to meet for teaming opportunities.

PROGRAM OBJECTIVE AND DESCRIPTION:

The Defense Advanced Research Projects Agency (DARPA) Cattle Run program seeks to enable cost-effective cislunar constellations by developing and demonstrating autonomous spacecraft that leverage solar sails or other renewable propulsion for station keeping and maneuverability over long mission durations in cislunar space. The program initially focuses on rapidly developing and launching a demonstrator spacecraft below geosynchronous earth orbit to show how renewable propulsion can achieve sufficient acceleration, accurate vehicle control, and autonomous Guidance, Navigation, and Control (GNC). Later objectives for the program include developing and launching multiple spacecraft to demonstrate cislunar operation.

REGISTRATION INFORMATION:

DARPA hosts Proposers Days to promote teaming arrangements between researchers; provide potential performers with information on whether and how they might respond to the Government’s research and development solicitations; and to increase efficiency in proposal preparation and evaluation. Therefore, Proposers Days are open only to registered potential proposers.
Participants must register No Later Than 12:00PM EST, 4 November 2026, at the following website: https://cvent.me/BVOW3V. Directions to the facility and other materials are also available on the website. There is no registration fee for attending this conference. Due to space limitations of the conference facility, attendance will be limited to the first 160 registrants, and no more than 2 representatives per organization.

ONE ON ONE SESSIONS:

Following the conclusion of the Cattle Run overview presentations, individual 10-minute one-onone sessions will be available during the Proposers Day with Mr. Steven Chambers from 1:005:00pm (EST). To request a session, please indicate your interest when registering. A follow-up