# Lionfish

**R-2A activity** of project 4023 — Expeditionary Underwater Systems  
**Program element:** 0604536N — Advanced Undersea Prototyping  
**Component:** U.S. Navy · **Budget Activity:** 4  
**Vintage:** President's Budget PB2027  
**Canonical URL:** https://hitchintel.com/programs/0604536N/4023/a1  
**Parent:** https://hitchintel.com/programs/0604536N/4023

> **NEW START.** $10.8M requested in FY2027 with no prior-year and no current-year funding.

## Summary

This activity requests $10.8M in FY2027, 61% of project 4023 — a new start with no prior-year and no current-year money. The R-2A exhibit describes it across FY2026–FY2027, including what the FY2027 money is planned to buy.

## What the FY2027 request buys

**FY2027 planned work.** FY 2027 continues fielding baseline Lionfish production units with spiral software upgrades as required. Funding will provide additional investments in the transition of advanced technologies. Efforts will include continued development and evaluation of artificial intelligence/machine learning algorithms, advanced autonomy behaviors and Automated Target Recognition (ATR) development. In FY27, Lionfish will continue maturing and field the Forward Looking Sonar- 9 inch (FLS-9) for fleet use and deliver increased capability through software updates to the vehicle's operating system and sensor packages, including updates to the FLS ATR algorithms. In FY 2027, funding is required to continue NRE efforts to finalize design, software/hardware integration and test of a Synthetic Aperture Sonar (SAS).

**FY2026 to FY2027 change.** Increase from FY 2026 to FY2027 is required to continue development and test/evaluation of planned vehicle improvements, while increasing efforts with advanced sensors in support of fielding synthetic aperture sonar designed for a small expeditionary UUV. Additional RDTE funds will also enable increased efforts in ATR, AI/ML, and software development by government and third parties to reduce detect-to-engage timelines and increase Sailor-machine teaming.

## Before the request year

**FY2026 plans — current year.** FY 2026 continues fielding baseline Lionfish production units. Funding will provide additional investments in the transition of advanced technologies. Efforts will include continued development and evaluation of artificial intelligence/machine learning algorithms, advanced autonomy behaviors and Automated Target Recognition (ATR) development. In FY26, Lionfish will continue maturing the Foward Looking Sonar- 9 inch (FLS-9) for fleet use and deliver increased capability through software updates to the vehicle's operating system and sensor packages, including updates to the FLS ATR algorithms. Conduct Initial Operational Test and Evaluation due to DOT&E oversight list. In FY 2026, funding is required to begin the NRE efforts for design, software/hardware integration and test of a Synthetic Aperture Sonar (SAS). This program was apart of PE 0604028N in FY26.

## Funding

| Fiscal Year | Estimate Type | Amount ($M) |
|---|---|---|
| FY2025 | Actual | 0.0 |
| FY2026 | Enacted | 0.0 |
| FY2027 | Request | 10.8 |

> Prior, current and budget year only — an R-2A activity carries no five-year plan. It sums exactly into its project in the request year and not necessarily in any other.

## Other activities in project 4023

- Viperfish — FY2027 5.7
- Swordfish and Kingfish — FY2027 1.2

## Source & machine access

- **Source:** FY2027 Department of the Navy RDT&E Budget Justification, Exhibit R-2A, PE 0604536N project 4023 (PB PB2027). Narrative is the government's own text.
- **No marks, no contractors at this grain** — congressional marks land on the program element and R-3 performers on the project.
- **MCP:** `mcp.hitchintel.com` — `budget_get_activity`.

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