---
title: "Project CALLISTO (PROPULSION)"
ocid: "ocds-h6vhtk-0542f8"
canonical_url: "https://d3tenders.com/contract/?ocid=ocds-h6vhtk-0542f8"
markdown_url: "https://d3tenders.com/contract/ocds-h6vhtk-0542f8.md"
json_url: "https://d3tenders.com/contract/ocds-h6vhtk-0542f8.json"
source: "Find A Tender Service"
current_stage: "Planning"
buyer: "MINISTRY OF DEFENCE"
published: "2025-06-04"
---

# Project CALLISTO (PROPULSION)

Buyer: MINISTRY OF DEFENCE  
Current stage: Planning  
OCID: ocds-h6vhtk-0542f8

[View canonical contract page](https://d3tenders.com/contract/?ocid=ocds-h6vhtk-0542f8)  
[Download OCDS JSON](https://d3tenders.com/contract/ocds-h6vhtk-0542f8.json)

## Summary

The Ministry of Defence (MOD) is currently in the planning stage of a procurement process for Project CALLISTO (PROPULSION), which focuses on military research and technology within the United Kingdom. The project seeks to develop a low-cost, 1.2-2kN propulsion system for the UK MOD's development programme, Proj BRAKESTOP. This initiative is significant due to its potential applications in heavy One Way Effectors and possibly other areas such as cruise missiles. A Project CALLISTO Challenge Session is scheduled for 18th June 2025 in London, with responses due by 10th June 2025. The MOD aims to commence full rate production of 20 engine units per month by Q2/Q3 2026, and is open to purchasing proven, off-the-shelf systems that promise security of supply.

This tender represents a substantial opportunity for businesses proficient in designing or manufacturing propulsion systems, particularly those with experience in creating cost-effective and scalable solutions. The MOD is targeting a unit price of £75K per propulsion system and is willing to support the development of new solutions if existing products fail to meet specifications. The project's broad technical requirements at this stage make it accessible to a range of companies, creating an environment ripe for innovation and collaboration. Firms established within the UK or planning to do so could gain a significant advantage in capturing a share of this lucrative defence sector opportunity.

## Notice

The UK MOD will be holding a Project CALLISTO Challenge Session on the afternoon of the 18th June 2025 in London, UK. Industry partners, particularly those currently established or planning to be established in the UK, are invited to attend to provide feedback on Project CALLISTO's proposed scope, timescales and feasibility. Additional information: The User requires a low-cost, 1.2-2kN propulsion system to power a UK MOD development programme (Proj BRAKESTOP) for a heavy One Way Effector (OWE). The propulsion system could be used for other applications e.g. cruise missiles, other OWEs. Project BRAKESTOP has highlighted limited availability of the class of propulsion systems needed. Therefore, MOD wishes to increase the availability of this class of propulsion system. Technical Propulsion Engine Requirements The engine shall: * Be a 1.2 - 2kN single engine propulsion system (Sea Level Static Maximum Thrust) o Low end for least amount of ancillary cost (facilities, fuel, equipment, build material, machine size, test cell etc) o Could then be iterated for enhanced capability. * Be designed to be easily manufactured at scale using widely available manufacturing methods/machinery. * Manage at least 5 hours component life; this provides confidence in managing the expected application life, but also pushes the materials technologies to low cost. * Be able to reliably start rapidly (ideally < 30 seconds) and accelerate to high power (ideally

## Key Details

| Field | Value |
| --- | --- |
| Publication source | Find A Tender Service |
| Latest notice | https://www.find-tender.service.gov.uk/Notice/029983-2025 |
| Notice type | Planning Notice |
| Procurement type | Standard |
| Procurement category | Services |
| Procurement method | Not Specified |
| Procurement method details | Not specified |
| Tender suitability | Not specified |
| Awardee scale | Not specified |
| All stages | Planning |

## Dates

| Field | Value |
| --- | --- |
| Publication date | 4 Jun 2025 |
| Submission deadline | Not specified |
| Future notice date | Not specified |
| Award date | Not specified |
| Contract period | Not specified |
| Recurrence | Not specified |

## Values

| Field | Value |
| --- | --- |
| Tender value | Not specified |
| Lots value | Not specified |
| Awards value | Not specified |
| Contracts value | Not specified |

## Status

| Field | Value |
| --- | --- |
| Tender status | Planned |
| Lots status | Not specified |
| Awards status | Not specified |
| Contracts status | Not specified |

## Buyer

| Field | Value |
| --- | --- |
| Main buyer | MINISTRY OF DEFENCE |
| Locality | BRISTOL |
| Post town | Bristol |
| Postcode | BS34 8JH |
| Country | England |
| ITL 1 | TLK South West (England) |
| ITL 2 | TLK5 West of England |
| ITL 3 | TLK52 Bath & North East Somerset and South Gloucestershire |
| Local authority | South Gloucestershire |
| Electoral ward | Stoke Park & Cheswick |
| Westminster constituency | Filton and Bradley Stoke |
| Delivery location | Not specified |

## CPV Codes

### Divisions

- 35 - Security, fire-fighting, police and defence equipment
- 73 - Research and development services and related consultancy services

### Codes

- 35613100 - Unmanned combat aerial vehicles
- 73410000 - Military research and technology

## Release History

- 4 Jun 2025 at 14:50 - Planning - Planning Notice - https://www.find-tender.service.gov.uk/Notice/029983-2025

## Notice URLs

- https://contracts.mod.uk/esop/guest/go/opportunity/detail?opportunityId=59907
- https://forms.office.com/Pages/ResponsePage.aspx?id=7WB3vlNZS0iuldChbfoJ5a5yEC87bndDi9PKmMmNOy9UN1ZYRkhMSkczNjBTOTlaUlBKTzREQ0w4VS4u

## Provenance

This Markdown file is an alternate public rendering of the D3 Tenders contract record. The canonical page is https://d3tenders.com/contract/?ocid=ocds-h6vhtk-0542f8. The underlying structured data is available as OCDS JSON at https://d3tenders.com/contract/ocds-h6vhtk-0542f8.json.