SESO

What SESO does

Thales SESO S.A.S. is a vertically integrated French manufacturer of large, ultra-precision optical components and opto-mechanical systems, headquartered in Aix-en-Provence and operating as a 100% subsidiary of Thales Alenia Space within the Thales Group. Founded in 1965, the company designs, grinds, polishes, coats, assembles and tests optics from a few centimeters up to 2 meters in diameter, with proprietary capabilities including 85% mirror lightweighting, sub-angstrom super-polishing, ion beam figuring yielding slope errors below 0.2 µrad, five vacuum coating chambers, ISO 5/7 clean-room integration, and more than 10 interferometer benches. Its product portfolio is organized across five verticals: Space (Korsch telescopes and mirrors for satellites such as Pleiades, KOMPSAT-3, GAIA, Sentinel-1A and SARAL), Astronomy (VLT-DSM, LBT secondary, DECam corrector, SALT spectrograph cameras, WFCAM), X-Rays (super-polished synchrotron mirrors, U-Benders, 4-Cylinder Benders and patent-protected Bimorph active mirrors with >1,300 units installed), Laser & Plasma (high-power optics for CEA's Laser MegaJoule, IRVIS endoscopes for the W7-X Stellarator), and Defense (BERSO dynamic test benches, collimators for the French DGA).

The company sells primarily through direct enterprise B2B relationships, supported by its affiliation with the Thales Group's global sales infrastructure and participation in technical conferences such as ICSO. Revenue is generated through custom manufacturing contracts — quote-based, specification-driven, one-time deliveries of optical components and integrated test systems — together with aftermarket and spare-parts support over the long lifecycle of space and scientific equipment. Its customer base is overwhelmingly institutional: ESA, CNES, KARI, ISRO, ESO, LBT, SALT, UATC, Australian Synchrotron, Synchrotron Soleil, CEA, Max Planck Institut für Plasmaphysik, and the French Defense Agency (DGA), with programs spanning Europe, North America, South America, the Middle East, Asia and Oceania. Quality is anchored in EN 9100:2018, ISO 9001:2015, AQAP 2110:2016, AQAP 2310:2017, ISO 14001:2015 and ISO 45001:2018 certifications, and the company positions itself as the number-one European manufacturer of large Zerodur mirrors for space and a world leader in bendable X-ray mirrors for synchrotrons.

Name

SESO

Legal name

Thales SESO S.A.S.

Website

https://seso.com

Company type

Private

Founded year

1965

Operating status

Operating

Headcount range

101–250 employees

Short description

Thales SESO is a French, vertically integrated manufacturer of large precision optics — space telescopes, astronomy mirrors, synchrotron X-ray optics, high-power laser optics and defense test benches — serving space agencies, observatories and research institutions worldwide.

Ownership category

akta.pro rank

Product category

Precision Optics Manufacturing

NAICS

Aerospace Product and Parts Manufacturing (33641), Other Guided Missile and Space Vehicle Parts and Auxiliary Equipment Manufacturing (336419), Search, Detection, Navigation, Guidance, Aeronautical, and Nautical System and Instrument Manufacturing (334511)

SIC

Optical Instruments & Lenses (3827), Guided Missiles & Space Vehicles & Parts (3760), X-Ray Apparatus & Tubes & Related Irradiation Apparatus (3844)

akta.pro primary industry

Space Payloads & Instruments (Sensors, Comms, EO/IR) (IMABACAD)

akta.pro secondary industry

Machine Vision & Optical Sensing (Cameras, 3D vision, LiDAR, illumination) (IMAGAFAB)

Keywords

• Precision optics manufacturing
• Space telescope mirrors
• Synchrotron x-ray optics
• Aerospace optical components
• Laser fusion optics

Headquarters

HQ city

Aix-en-provence

HQ country

France

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Infrastructure, Operations, Supply Chain, Marketing or Sales

Revenue model

1. Custom Optical Component Manufacturing: B2B manufacturing of custom precision optics for space, astronomy, defense, X-ray and laser applications. Revenue generated through long-term contracts for satellite programs, telescope instrumentation, and scientific research facilities. Products include mirrors, lenses, collimators, and integrated opto-mechanical systems.
2. Test Systems and Equipment: Design and manufacture of complex test systems including optical ground support equipment (OGSE), dynamic test benches (BERSO), and solar simulators. One-time custom equipment sales to defense and space customers.
3. Aftermarket and Spare Parts: Ongoing support, spare parts, and potential upgrades for delivered optical systems. Given the long lifecycle of space and research equipment, may generate recurring service revenue.

Go-to-market motion2 records

Distribution channels1 record

Marketing channels4 records

Core offering

SESO designs and manufactures large precision optics and opto-mechanical systems for space, astronomy, X-ray, laser/plasma, and defense applications. Operating from its Aix-en-Provence facility, the company is vertically integrated across optical and mechanical design, milling/grinding, polishing, lightweighting, optical coating, assembly, integration, and testing — producing mirrors, lenses, telescopes, collimators, benders, and bimorph active mirrors up to 2 meters in diameter with sub-nanometer precision. The company supplies bespoke optical components and integrated test systems directly to space agencies, observatories, synchrotrons, fusion laboratories, and defense agencies.

Product overview

SESO is a vertically integrated manufacturer of precision optical systems and components, operating as a 100% Thales subsidiary under Thales Alenia Space. The company offers a comprehensive portfolio of large precision optics for Space (Korsch telescopes, satellite mirrors), Astronomy (telescope optics, spectrographs), X-rays (synchrotron mirrors, benders, bimorph mirrors), Laser & Plasma (high-power laser optics, endoscopes), and Defense (test benches, collimators) applications. The product portfolio is supported by integrated in-house capabilities spanning optical and mechanical design, milling/grinding, polishing (up to 2m), lightweighting (up to 85%), optical coating (5 vacuum chambers), assembly/integration (ISO 5/7 clean rooms), and precision testing (interferometry, coordinate measuring). Key products include Korsch telescopes for Pleiades and KOMPSAT satellites, SESO® Benders and Bimorph for X-ray applications, BERSO dynamic test benches for defense, and specialized optics for major observatories including VLT, LBT, and GTC. The company maintains over 80 manufacturing machines and robots to ensure flexibility for demanding customer specifications.

Differentiator

Problem solved

Functional benefit

Brands

• SESO® Benders: U-Benders and 4 Cylinder Benders for horizontal focusing mirrors for beamlines
• SESO® Bimorph
• SESO® X-Ray Mirrors
• SESO® Optics

Products and services

• Space Optics Precision optics and opto-mechanical systems for space applications, including Korsch telescope assemblies (KOMPSAT-3, Pleiades, ETGAR), satellite mirrors, photometer prisms (GAIA), laser communications terminal mirrors (Sentinel-1A), and laser retro-reflector arrays (SARAL). Sold to space agencies and satellite manufacturers requiring sub-nanometer precision and space-qualified components.
• Astronomy Optics High-accuracy optics for ground-based astronomy including telescope mirrors, multi-lens optical correctors (e.g., DECam 5-lens Wynn-style corrector), spectrograph camera assemblies (e.g., SALT HRS), deformable secondary mirror reference bodies (VLT-DSM), and fully integrated opto-mechanical systems for observatories worldwide. Sold to astronomical observatories and research institutions.
• X-Ray Optics Super-polished X-ray mirrors, bendable focusing mirrors (U-Benders and 4 Cylinder Benders), and bimorph active mirrors for synchrotron beamlines and XFELs. Achieves slope errors <0.2 µrad on mirrors up to 1.5 meters long and 0.1 µrad on mirrors up to 600mm. Sold to synchrotron radiation facilities and XFEL operators globally.
• Laser & Plasma Optics High-power laser optics and specialized endoscopes for plasma physics research. Includes 7 optical components per beam (windows and lenses) for the 196 beams of CEA's Laser MegaJoule, and IRVIS endoscopes for the Max Planck W7-X Stellarator fusion experiment. Achieves slope errors as low as 0.7 µrad with roughness <2Å for LMJ optics.
• Defense Optics State-of-the-art optical and optronic systems for defense applications, including dynamic test benches (BERSO) for infrared missile guidance detector head testing, parabolic collimators, and optronics benches with infrared optical channels, blackbody sources, and motorized movements. Sold to defense agencies and defense contractors.
• SESO® Bimorph Active bimorph mirror product line protected by Patent 1000471-05/02/2010. The patented design removes artifacts due to limited piezoelectric ceramic length and enables double-sided polishing of active mirrors. Sold to synchrotron facilities for beamline applications requiring active mirror control.
• SESO® Benders Bendable focusing mirror product line including U-Benders (with one or two actuators) and 4 Cylinder Benders designed for horizontal focusing mirrors on synchrotron beamlines. Sold to synchrotron radiation facilities requiring bendable X-ray optics.
• SESO® Collimators Parabolic collimator product line available in centered or off-axis configurations with standard quality from λ/30 to λ/40 RMS. Includes standard catalog models in multiple focal length and diameter configurations. Sold to defense, space, and research customers for optical testing and integration.
• BERSO Dynamic Test Bench BERSO dynamic test bench for testing infrared missile guidance detector heads. A complex opto-mechanical system integrating infrared optical channels, blackbody sources, motorized movements, and a common wide field illumination collimator. Sold to defense agencies and defense contractors.

Quantifiable outcome

• Lightweighting up to 85% of original mirror weight while maintaining stiffness
• +5 more outcomes

Named customers15 records

Segments5 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature8 records

Partnerships

Five partnerships are on record, tiered core.

• CEA (Commissariat à l'énergie atomique et aux énergies alternatives)coreStrategic or Co-development PartnerStrategic partnership with CEA for the Laser MegaJoule (LMJ) program. Thales SESO is responsible for producing 7 optical components per beam for all 196 beams of the LMJ. Working closely with CEA to define new processes and install dedicated production line to meet exceptional quality requirements for high-power laser optics.
• Max Planck Institut für PlasmaphysikcoreStrategic or Co-development PartnerSelected by Max Planck Institut für Plasmaphysik for design, production and installation of 2 IRVIS endoscopes for W7-X Stellarator fusion experiment. Endoscopes operate in harsh UHV environment with internal cooling, qualified welding, and ultimate cleaning requirements. Positions company for ITER optical instruments.
• Thales Alenia SpacecoreStrategic or Co-development Partner100% subsidiary reporting to Thales Alenia Space, which is Thales space global business unit (joint venture between Thales and Leonardo). Quality system integrated into Thales Alenia Space QHSE system (Chorus TAS). Thales Alenia Space serves as prime contractor for major programs like Pleiades.
• Synchrotron SoleilcoreStrategic or Co-development PartnerPartnership for bimorph active mirrors used on Proxima Beamline at Synchrotron Soleil. Design based on Patent 1000471 removes artifacts from piezoelectric ceramics, enabling active mirrors polished on both sides.
• Australian SynchrotroncoreStrategic or Co-development PartnerDeployment of SESO Bimorph active mirrors with artifact-free design for synchrotron beamline applications.

Scale indicators10 records

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Coherent Corp (formerly II-VI): Coherent manufactures precision optical components, coatings, and laser optics across aerospace, defense, and semiconductor end markets. Comparable to SESO in advanced optics manufacturing but at much larger scale and broader portfolio including laser systems and materials.
• L3Harris Technologies: L3Harris is a large US defense prime that supplies space-based optical payloads, EO/IR sensors, and surveillance instruments — overlapping with SESO's space optics and defense test systems, but at a much broader portfolio level rather than as a pure-play optics specialist.
• Honeywell Aerospace: Honeywell's aerospace division supplies space-qualified optics, inertial sensors, and EO/IR payloads. Comparable customer set (government/space agencies) and some overlap in space-based optical assemblies, though not a focused large-optics manufacturer.
• BAE Systems (formerly Ball Aerospace): BAE Systems' Space & Mission Systems (absorbing Ball Aerospace) manufactures telescopes, mirrors, and optical instruments for science and defense missions (e.g., Hubble, JWST programs). It competes with SESO for institutional space optics awards but as part of a much larger aerospace integrator.
• Northrop Grumman: Northrop Grumman is a US defense prime producing space telescopes, large-aperture optics, and laser systems, competing for the same institutional astronomy and defense programs as SESO. Broad incumbent rather than a niche optics specialist.

Regional players

• Sagem (Safran Electronics & Defense): Sagem, part of Safran Electronics & Defense, produces optronic systems, infrared sensors, and defense test equipment — overlapping with SESO's defense optics and BERSO-style test benches, primarily in the French/European defense market.

Direct peers

• Carl Zeiss: Zeiss's optics and semiconductor divisions produce high-precision mirrors, lens systems, and metrology optics for astronomy, semiconductor lithography, and space — overlapping with SESO's super-polishing, lightweighting, and large-aperture capabilities. Both compete on flagship astronomy and lithography-grade optics.
• Jenoptik: Jenoptik produces high-precision optical components and systems for semiconductor, defense, and metrology end markets, including lightweighted mirrors and complex opto-mechanical assemblies. Directly comparable to SESO in precision optical manufacturing and defense/aerospace customer overlap.
• Schott AG: Schott manufactures Zerodur glass-ceramic substrates — the same material SESO machines and polishes for space telescopes — making Schott both a critical supplier and a vertical competitor when Schott delivers finished mirror blanks. Direct overlap in large Zerodur optics for space and astronomy.
• Safran Reosc: Safran's Reosc subsidiary is the most direct French competitor to SESO, manufacturing large precision optics for space telescopes, Earth-observation satellites, astronomy, and high-power laser applications. Both serve overlapping institutional customers (ESA, CNES, ESO, CEA) and compete head-to-head for flagship optical assemblies.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat6 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/thales-seso

Compliance6 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about SESO