# Surface Ship Torpedo Defense — Program Element 0603506N

**Program element:** 0603506N  
**Component:** U.S. Navy  
**Appropriation:** 1319 — RDT&E, Navy  
**Budget Activity:** 4 — Advanced Component Development & Prototypes  
**Vintage:** President's Budget PB2027  
**Canonical URL:** https://hitchintel.com/programs/0603506N

## Summary

U.S. Navy funding falls 16% to a $9.9M request in FY2027, sustained across the five-year plan. In the FY2027 defense authorization, the House funded it in full; the Senate funded it in full; House appropriators funded it in full. Sonalyst leads the industry work, though an unusually large share flows to government labs and warfare centers.

## Funding profile

| Fiscal Year | Estimate Type | Amount ($M) |
|---|---|---|
| FY2025 | Actual | 4.6 |
| FY2026 | Enacted | 11.8 |
| FY2027 | Request | 9.9 |
| FY2028 | Outyear | 25.8 |
| FY2029 | Outyear | 28.1 |
| FY2030 | Outyear | 40.7 |
| FY2031 | Outyear | 41.4 |

> Estimate types are not summed — the profile mixes actuals, enacted law, the request, and outyear projections.

## Congressional marks (FY2027)

| Stage | Marked ($M) | Change ($M) |
|---|---|---|
| Request | 9.9 | — |
| House NDAA (HASC) | 9.9 | +0.0 |
| Senate NDAA (SASC) | 9.9 | +0.0 |
| House Approps (HAC-D) | 9.9 | +0.0 |

> FY2027 NDAA authorization marks, as of 2026-07-27. Not appropriations or final law.

## Projects (1)

| Project | Title | FY2025 actual | FY2026 enacted | FY2027 request | Move |
|---|---|---|---|---|---|
| 0225 | Surface Ship Torpedo Defense (SSTD) | 4.6 | 11.8 | 9.9 | −16% |

> Projects are the summable leaves: the program element total is their sum, never added to it.

### Project 0225 — Surface Ship Torpedo Defense (SSTD)

Anti-Torpedo Torpedo Defensive System (ATTDS) is a system of systems, comprised of the TWS and the CAT planned to develop NIXIE HK new AN/SLQ-25 capabilities in order to pace the torpedo threat. This includes integrating and testing a kinematics-based target discrimination and fire control into the AN/SLQ-25E, improving existing soft kill capabilities within AN/SLQ-25E, and adding a hard kill capability with a launcher for the MK 58 CRAW and the (ADC) MK5 and MK 2 Mod 6/8. The funds support the development of a torpedo alertment and fire control capability integrated into the AN/SLQ-25E tow system in support of a torpedo defense requirements along with software improvements to specific NIXIE counter measures.

**Named R-3 performers** (share of this project's FY2027 R-3 total, so they need not reach 100%)**:** Sonalyst (1.1, 11%), SAIC (0.4, 4.4%), Ultra (0.3, 3.3%), Synchron (0.3, 3.0%).

| Activity (R-2A) | FY2025 | FY2026 | FY2027 |
|---|---|---|---|
| Torpedo Warning System (TWS) | 4.6 | 2.4 | 0.9 |
| SLQ-25 (NIXIE) Capability Improvements | 0.0 | 1.3 | 1.3 |
| Torpedo Hardkill Development | 0.0 | 8.1 | 7.7 |

> R-2A activities carry the prior, current and budget year only — no five-year plan. Coverage is partial, so count them, never total them.

## Where the FY2027 request goes

| Category | Share | $M |
|---|---|---|
| Industry primes | 21% | 2.1 |
| Government labs & warfare centers | 30% | 3.0 |
| Other / unspecified | 49% | 4.8 |

**Top named industry performers:** Sonalyst ($1.1M, 11%), SAIC ($0.4M, 4.4%), Ultra ($0.3M, 3.3%), Synchron ($0.3M, 3.0%).

> R-3 exhibit contract funding, not USAspending obligations.

## Mission & acquisition strategy

The Surface Ship Torpedo Defense (SSTD) program provides a detect-to-engage layered torpedo defense capability. The four (4) major efforts that comprise SSTD are the AN/SLQ-25 (NIXIE) system, Torpedo Warning System (TWS), the Countermeasure Anti-Torpedo (CAT), and Acoustic Device Countermeasure (Surface ADC MK2). A layered torpedo defense to protect surface ships against current and future threats. SSTD development will include a new anti-torpedo Hard Kill (HK) capability by pairing proven technology and the MK 58 the Compact Rapid Attack Weapon (CRAW) with improved AN/SLQ-25E that has additional software capabilities.

Torpedo Warning System (TWS) Program: ULTRA developed and produced five complete sensor sets. Pacific Engineering Incorporated (PEI) and In-Depth Engineering INC. developed the stowage racks and fire control systems respectively. System integration supported fabrication and fielding of the five complete systems. Testing of TWS SALVO software was complete and is currently in Fleet use. ULTRA continues to provide Fleet support for the system. AN/SLO-25E NIXIE Torpedo Hardkill Program will leverage the technologies developed in the TWS and CAT then incorporates them into the tow system and CRAW of the NIXIE 25E system.

## Related program elements

- [0101226N — Submarine Acoustic War Dev](https://hitchintel.com/programs/0101226N) (Navy)
- [0603892C — AEGIS BMD](https://hitchintel.com/programs/0603892C) (Defense-Wide)
- [0604234N — Advanced Hawkeye](https://hitchintel.com/programs/0604234N) (Navy)
- [0202834F — Aviation Support Equipment Modernization](https://hitchintel.com/programs/0202834F) (Air Force)

## Source & machine access

- **Source:** FY2027 Department of the Navy RDT&E Budget Justification, Exhibits R-2/R-3, PE 0603506N (PB PB2027); FY2027 NDAA committee marks (as of 2026-07-27).
- **MCP:** `mcp.hitchintel.com` — `budget_get_program_element(pe="0603506N")`.

*HitchAI is an independent intelligence service, not affiliated with the U.S. Department of Defense. Budget figures are requests/estimates, not obligations.*