***Amendment 4 updates Attchment 1, Topic Area B5. ***Amendment 3 updates Attachment 1, Topic Area B4. ***Amendment 2 incorporates an updated Attachment 1 - Specific Topics to include Topic Areas B1-B6. This amendment also establishes a deadline for pre-application white papers for Topic Areas B1-B6 of March 2, 2026 at 11:59PM EST. This is the initial announcement of this funding opportunity. This BAA is in effect from October 1, 2024 through September 30, 2034. It is anticipated that a majority of the actions funded from this announcement will be in the form of grants; however, other instruments such as cooperative agreements (CAs) or other transactions (OTs) for research may also be awarded from this announcement. No contracts will be awarded from this announcement. Submissions for this BAA may occur in two ways: 1) in response to the published topics detailed in Attachment 1 or 2) to a general thrust area as described in Section 1.5. In general, all topic-specific and general thrust area submissions require pre-coordination in accordance with the guidelines in Section 1.5 and Section 4.2.1. DTRA reserves the right to waive the pre-coordination requirement for topics on a case-by-case basis; and will state the waiver applies within the individual topic description. If a pre-application white paper is received without prior coordination, DTRA may not review it. From the date of the disposition email the applicant has 63 days to submit the pre-application white paper. If the submission is not feasible within this 63-day window, the abstract must be coordinated again to ensure the interest in the white paper remains. The evaluation of all submissions will be conducted in two phases. Phase I is for receipt and evaluation of pre-application white papers in direct response to a published topic or by invitation based on the assessment of the idea by the Technical POC. Phase II is for receipt and evaluation of invited proposal applications. Invitation to the Phase II, invited proposal submission, will be based on the evaluation results of the Phase I pre-application white paper. Catalog of Federal Domestic Assistance (CFDA) Number: 12.351 This BAA is open continuously from October 1, 2024 through September 30, 2034. Published topics will include instructions on any topic-specific opening and closing dates as well as any topic-specific limitations on award types, dollar values, and eligibility. Submissions to a general thrust area may occur at any time this BAA is in effect. Applicants should take care to note requirements for pre-coordination of an abstract. DTRA safeguards America and its allies from weapons of mass destruction (WMD) and provides capabilities to reduce, eliminate, and counter the threat and effects from chemical, biological, radiological, nuclear, and high yield explosives. DTRA seeks to identify, adopt, and adapt emerging, existing, and revolutionary sciences that may demonstrate high payoff potential to Counte…