UK MoD signs contract for Sceptre 155 mm round development

The UK Ministry of Defence (MoD) has signed a contract with Tiberius Aerospace for the development and trials of the company’s ramjet powered, Sceptre 155 mm artillery shell, according to a September 4 press release.   

“The specific details of the contract cannot be disclosed, but this contract puts the UK MoD in the position of being the launch customer for Tiberius Aerospace, investing in this exciting new technology and the US Defence Innovation Unit (DIU) which is facilitating the independent verification and validation for the testing of the technology,” the press release states. 

Sceptre was unveiled in May this year and covered in a Calibre Defence exclusive article. Since then, the round has been through a series of live fire trials as well as simulations to further refine the design. At the time of its release, Tiberius Aerospace was primarily working on conventional breech-loaded guns like the M777, which have the room to the rear of the breech to load the round. However, it was also developing a version of the round that could be fired from a system with an automatic loader, like the UK’s Archer self-propelled howitzer. 

This would presumably be necessary for the UK MoD contract, as Archer is the only 155 mm howitzer currently in service with the UK. Moreover, the RCH155 that is set to join the Archers is also fed by an automatic loader. Earlier presentations from the British Army indicated that the BONUS anti-armour round would be qualified for use from its Archer fleet. BONUS, which has two submunitions that fire explosively formed projectiles through the roof armour of vehicles. 

Tech profile: Sceptre 155 mm round 

The Sceptre, formally designated TRBM 155HG, is a 155mm extended-range, precision-guided artillery round designed to be fired from NATO-standard 155mm howitzers. It uses a ramjet engine to achieve supersonic speeds and ranges far beyond conventional artillery. The round’s guidance system allows for high-precision strikes, even in GPS-contested environments, according to Tiberius Aerospace. 

• Range: Up to 150 km.
• Warhead: 5.2 kg of explosive payload, with fragmentation capability. It can also be fitted with a tungsten core for enhanced armor-piercing effects. 
• Size: 1.55 meters long with a 155 mm diameter. Its all-up launch weight is 47.5 kg.
• Propulsion/Fuel: A liquid-fueled ramjet engine. It’s compatible with multiple fuel types, including diesel, JP-4, and JP-8. The howitzer’s propelling charge provides the initial velocity needed to ignite the ramjet, which then sustains the round’s flight.

Calibre comment

The British Army is placing a lot of emphasis on the role of deep strikes in its doctrine. The theory is that extensive deep strikes against an adversary will degrade its frontline capability, enabling the UK’s limited armoured combat mass to fight an unfair fight. This is leading to development and procurement of several long-range systems. Earlier indications were that the country would receive the GMLRS-ER rockets for its M270 MRLS, which has a range of 150 km. 

It has also stated its interest in procuring the Precision Strike Missile (PrSM) from Lockheed Martin, but had not signed a contract as of January this year. More recently, Project NIGHTFALL was announced, which is intended to develop a 600 km range ballistic missile. Some sources indicate that it may be for Ukraine, but could also support the British Army and domestic capabilities. The Sceptre could add an additional long-range capability to the Army’s artillery park, assuming that it can properly resource its reconnaissance needs, which will partly be met by Project CORVUS. 

Separately, it is worth noting that not all analysts agree on the value of deep strikes as the leading edge of an army’s doctrine. There is conflicting evidence from Ukraine and elsewhere, which suggests that its effects may not be as pronounced as had been hoped. Others consulted by Calibre Defence indicate that the effects are very real and disruptive, and can serve to meaningfully spare armoured combat power from excess attrition. 

By Sam Cranny-Evans, published on September 7, 2025. Credit for the lead image is Resilience Media.