Solar Defence Facility Images Show Large Loitering Munition Airframe Linked to 150 Kg CSIR-NAL Programme

New images reported from a Solar Defence & Aerospace facility have drawn attention to a substantially larger unmanned airframe than the company’s existing Nagastra loitering munitions. The aircraft has been linked in defence reporting to the 150 kg-class Loitering Munition UAV being developed jointly by Solar Defence & Aerospace Ltd and CSIR-National Aerospace Laboratories.

The connection is plausible because Solar Defence is the officially selected industrial partner for CSIR-NAL’s 150 kg LM-UAV programme. However, neither CSIR-NAL nor Solar Defence has publicly confirmed that the aircraft visible in the latest images represents the final configuration of that programme. The airframe should therefore be viewed as potentially associated with the project rather than treated as a confirmed production design.

CSIR-NAL Began the 150 Kg Loitering Munition Programme in 2024

CSIR-NAL formally initiated the programme through a Request for Proposal issued in August 2024 for joint research, development, manufacturing and commercialisation of an indigenous 150 kg-category loitering munition UAV.

The objective went considerably beyond developing a small battlefield loitering weapon. NAL sought an aircraft capable of combining extended endurance, long operational reach, autonomous navigation and a substantial warhead with an indigenous propulsion system.

The original RFP specified an overall aircraft weight below 150 kg and proposed performance objectives including a maximum range of around 900 km, endurance of six to nine hours and a maximum operating altitude of approximately five kilometres.

These figures are programme targets rather than confirmed performance figures for an operational aircraft.

Solar Defence Selected as CSIR-NAL’s Industrial Partner

Competition for the programme attracted several major Indian defence and aerospace companies.

CSIR-NAL’s technical evaluation in March 2025 shortlisted Tata Advanced Systems, Adani Defence Systems & Technologies, Economic Explosives of the Solar group, Raphe mPhibr, Bharat Electronics, Bharat Dynamics, NewSpace Research & Technologies and Triveni Engineering & Industries.

The subsequent techno-commercial evaluation placed Solar Defence & Aerospace at the top with a combined technical-commercial score of 80.30. Bharat Dynamics followed with 78.62, while Raphe mPhibr received 76.78.

NAL stated that the collaboration would first be offered to the company receiving the highest combined score.

The process eventually resulted in Solar Defence & Aerospace becoming the industrial partner for the programme.

CSIR-NAL and Solar Defence Formalised the Collaboration

CSIR-NAL and Solar Defence & Aerospace formally exchanged their collaboration agreement in late 2025 for development of the indigenous loitering munition UAV.

The agreement placed the two organisations together across the design, development and testing phases rather than limiting Solar Defence’s involvement to manufacturing an already completed government design.

That structure gives the industrial partner an important role in translating NAL’s aerospace technologies into a system designed for eventual production and operational deployment.

It also fits India’s broader effort to combine government research laboratories with private-sector manufacturing capacity for strategically important defence technologies.

900 Km Range and Nine-Hour Endurance Are Development Targets

The official CSIR-NAL requirement outlines an aircraft considerably larger and more capable than tactical loitering munitions normally designed for short-range battlefield engagements.

NAL identified a maximum range objective of 900 kilometres, with endurance extending to nine hours. The proposed aircraft is intended to operate at altitudes of up to approximately five kilometres.

Its wingspan is expected to remain below four metres, while the launch architecture calls for an assisted-launch arrangement rather than dependence on a conventional runway.

A combination of long endurance and extended range would allow the aircraft to remain airborne while searching for or approaching designated targets rather than following the direct launch-to-target profile normally associated with conventional missiles.

15 Kg Warhead and Dedicated Sensor Payload

The original programme envisages a warhead weighing approximately 15 kg, accompanied by a dedicated sensing payload.

NAL’s RFP specifies around 10 kg of sensing equipment, while earlier programme descriptions allowed roughly 10–15 kg for suitable sensors.

This separation between the warhead and surveillance payload is significant. A long-range loitering munition requires more than explosive payload capacity. It also needs sensors capable of detecting, identifying and tracking targets before an engagement decision is made.

The final sensor configuration has not been publicly disclosed.

Indigenous Wankel Engine Will Power the Loitering Munition

One of the most important elements of the programme is its propulsion system.

CSIR-NAL intends the 150 kg LM-UAV to use an indigenous Wankel rotary engine developed by NAL. The collaboration announcement said the engine had already progressed through certification activity for aircraft integration and flight testing.

Wankel engines offer several characteristics useful for unmanned aircraft, including a compact configuration and favourable power-to-weight characteristics. For an endurance-oriented loitering munition, propulsion efficiency must also support several hours of sustained flight while carrying fuel, sensors, avionics and the warhead.

Developing the engine domestically reduces dependence on imported propulsion technology in an area that can otherwise become a major bottleneck for indigenous UAV programmes.

GPS-Denied Navigation Is Part of the Requirement

NAL has specifically included the ability to operate in GPS-denied environments among the proposed capabilities of the aircraft.

Modern electronic warfare can disrupt or deceive satellite-navigation signals through jamming and spoofing. An unmanned strike system intended to operate hundreds of kilometres from its launch position therefore requires alternative navigation methods to retain mission capability when satellite positioning becomes unreliable.

The programme also calls for increased levels of autonomy and indigenous hardware and software.

Detailed information about the navigation architecture remains restricted, but the requirement indicates that survivability against electronic warfare forms part of the design philosophy from the outset.

Low Radar Cross-Section Features Are Also Planned

Another notable requirement is the incorporation of design features intended to achieve a comparatively low radar cross-section.

This does not necessarily make the aircraft a fully stealth platform. Radar observability depends on numerous factors including airframe geometry, materials, engine installation, operating altitude and the frequency bands used by opposing radars.

NAL’s published requirement is more carefully framed around improving survivability through comparatively low-RCS characteristics.

The large airframe appearing in the recently circulated images has prompted interest partly because its configuration looks different from Solar Defence’s smaller Nagastra systems. Visual appearance alone, however, cannot establish the aircraft’s actual radar signature or confirm its final aerodynamic design.

New Airframe Is Much Larger Than the Nagastra Family

Solar Defence already has extensive experience developing loitering munitions through its Nagastra family.

Nagastra systems occupy a lighter tactical category intended for battlefield employment. The 150 kg CSIR-NAL project represents a different scale of unmanned strike capability, with much greater endurance, payload capacity and projected reach.

Images reported on October 2, 2026 show a large aircraft at a Solar Defence facility with proportions substantially exceeding those associated with the smaller Nagastra weapons.

This physical difference is one reason the airframe has been linked to the CSIR-NAL programme. The location and size support that interpretation, but they do not provide sufficient evidence to identify every visible design feature as belonging to the final 150 kg LM-UAV.

Solar Defence Has Expanded Its UAV Testing Infrastructure

The development is taking place alongside a major expansion of Solar Defence’s unmanned-systems infrastructure in Nagpur.

The company has established facilities for testing loitering munitions and larger UAV systems, including a dedicated test range and runway infrastructure. This creates an environment where propulsion, guidance, endurance, communications, recovery systems and eventual weapon integration can be evaluated within the company’s own ecosystem.

Such infrastructure becomes increasingly important as Indian private-sector UAV programmes move from relatively small systems towards larger aircraft requiring longer flight testing and more complex integration.

The 150 kg LM-UAV is particularly demanding because it brings together a new aircraft, indigenous propulsion, autonomous navigation, sensors, survivability features and a sizeable warhead within a single platform.

A Different Class of Indigenous Loitering Munition

The CSIR-NAL and Solar Defence programme represents an effort to move India’s loitering-munition capability into a significantly heavier and longer-range category.

Rather than replicating a small tactical kamikaze drone, the project aims to combine extended endurance, deep reach, autonomous operation, precision sensing and indigenous propulsion in an aircraft weighing less than 150 kg.

Several stages remain before the programme can be considered operational. The configuration will need to progress through development, ground testing, flight trials, navigation and sensor validation, weapons integration and eventual user evaluation.

The newly observed airframe provides an intriguing indication that physical development may be advancing, but official confirmation will be needed before it can definitively be identified as the final CSIR-NAL/Solar Defence LM-UAV.

The programme itself is firmly established. With Solar Defence now partnered with India’s national aerospace laboratory and domestic propulsion, avionics and manufacturing forming central elements of the design, the 150 kg LM-UAV programme is building another indigenous capability in India’s rapidly expanding unmanned combat-aircraft ecosystem.

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References

CSIR-National Aerospace Laboratories — Request for Proposal for Joint Collaboration in R&D, Manufacturing and Commercialization of 150 kgs Category Loitering Munition (LM) UAV, RFP dated August 23, 2024. CSIR – NAL

CSIR-National Aerospace Laboratories — Evaluation of Technical Bids for Joint Collaboration in R&D, Manufacturing and Commercialization of 150 Kg Category Loitering Munition, March 5, 2025. CSIR – NAL

CSIR-National Aerospace Laboratories — Evaluation of Techno-Commercial Bids, June 27, 2025. CSIR – NAL

CSIR-National Aerospace Laboratories — Exchange of the Collaboration Agreement between CSIR-NAL and Solar Defence & Aerospace Ltd for development of CSIR’s indigenous Loitering Munition UAV, December 2025. CSIR – NAL

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