Proba-3 is a pair of ESA spacecraft that fly in formation, one blocking the Sun so the other can image its corona.
esa-proba-3 Proba-3 is a pair of spacecraft, made by the European Space Agency (ESA) and Airbus, that fly in precise formation. Together they form a solar coronagraph about 150 m long. The Occulter carries a disc 1400 mm across that blocks the Sun, and the Coronagraph spacecraft images the corona, the Sun's outer atmosphere.
Both craft are wrapped in black multi-layer insulation, a layered thermal blanket. The colour is deliberate: LEDs on board show up against it with maximum contrast. The coronagraph instrument rests on a carbon-fibre optical bench, and an antenna was 3D printed in aluminium.
One of a pair of ESA spacecraft that fly in precise formation, one blocking the Sun so the other can image the corona. The black multi-layer insulation on both spacecraft is part of how the formation is tracked and kept thermally stable.
Both spacecraft wear the same black blanket. Technicians from Aviotec wrapped the Coronagraph spacecraft in it. Thermal control also uses thermistors, which sense temperature, plus heaters and radiators.
An optical bench is the stable base that holds a telescope's optics. This one is made of high-stability sandwich panels, carbon-fibre plastic over an aluminium core, with titanium fittings to attach the instrument units.
The coronagraph instrument, ASPIICS, has a main tube and an equipment box, both in aluminium alloy. Three titanium bipods, two-legged struts, support it. Its main lens is split in two, one piece of BK7G18 glass and one of SF6G05, both glasses that resist radiation.
A coil-shaped helical antenna was 3D printed in an aluminium alloy by SENER Aeroespacial with CATEC. Power comes from gallium arsenide solar cells and lithium-ion batteries, feeding a battery-regulated 28 V power bus, the main electrical supply line.
The black outer blanket on both spacecraft.
The skins of the optical bench's sandwich panels.
The coronagraph tube and equipment box, and the 3D-printed helical antenna.
Fittings on the optical bench and the three instrument support bipods.
The two lenses of the main objective, BK7G18 and SF6G05.
The batteries that feed the regulated 28 V power bus.
Proba-3 is one of ESA's Proba missions. A PSLV-C59 rocket launched it on 5 December 2024. Aviotec did the insulation wrapping on the Coronagraph spacecraft, and SENER Aeroespacial worked with CATEC on the printed antenna.
ESA
Aluminium. Here: Main structure tube; Equipment box (EQB) and more. There: Telescope (structure and mirrors, 3 telescopes).
Titanium. Here: OBA unit attachment fittings; Instrument support bipods (3). There: Focal plane interconnecting structure; Instrument mounting feet / flexures and more.
Multilayer insulation. Here: Outer thermal blanket (both spacecraft). There: Instrument thermal wrap.
Carbon fibre. Here: OBA sandwich panels. There: Outer panels (3).
Li-Ion batteries. Here: Batteries and solar cells. There: Battery.
NASA Goddard Space Flight Center
Aluminium. Here: Main structure tube; Equipment box (EQB) and more. There: Primary structure (heating/cooling panel, edge members, fittings, brackets); Optical-bench heater aluminum tape and more.
Titanium. Here: OBA unit attachment fittings; Instrument support bipods (3). There: Propellant tanks (2); Instrument mounting flexures.
Multilayer insulation. Here: Outer thermal blanket (both spacecraft). There: High Gain Antenna multi-layer insulation and heaters.
Li-Ion batteries. Here: Batteries and solar cells. There: Battery cells.
NASA
Aluminium. Here: Main structure tube; Equipment box (EQB) and more. There: Pressure vessel (seven large pieces, friction-stir welded); Backbone assembly (floor structure) and more.
Titanium. Here: OBA unit attachment fittings; Instrument support bipods (3). There: Heat shield skeleton.
Multilayer insulation. Here: Outer thermal blanket (both spacecraft). There: Passive thermal control: multilayer insulation blankets (incl. high-temperature blankets at thrusters and nozzle) and heaters.
Carbon fibre. Here: OBA sandwich panels. There: Core panels (webs, tank bulkhead, lower platform); Solar array wings (x4, X-wing, three panels each) with wing-tip cameras.
NASA / JPL
Aluminium. Here: Main structure tube; Equipment box (EQB) and more. There: Wheel body (6).
Titanium. Here: OBA unit attachment fittings; Instrument support bipods (3). There: Wheel spokes; Legs / suspension tubing and more.
Carbon fibre. Here: OBA sandwich panels. There: Heat shield facesheets.
Li-Ion batteries. Here: Batteries and solar cells. There: Rechargeable batteries (2).
SpaceX
Aluminium. Here: Main structure tube; Equipment box (EQB) and more. There: Tank domes (aluminium).
Titanium. Here: OBA unit attachment fittings; Instrument support bipods (3). There: Grid fins, titanium version.
Carbon fibre. Here: OBA sandwich panels. There: Interstage face sheets; Landing legs.
Li-Ion batteries. Here: Batteries and solar cells. There: Lithium-ion batteries (redundant, on each stage).
ESA
Aluminium. Here: Main structure tube; Equipment box (EQB) and more. There: TPMU/DSLP housing.
Carbon fibre. Here: OBA sandwich panels. There: Platform structure supplier (eoPortal).
Li-Ion batteries. Here: Batteries and solar cells. There: Battery.
The makers do not name the film layers in the insulation, the materials of the two spacecraft bodies, or what the Occulter's disc is made of. Fasteners, coatings, adhesives and the make of the solar cells are missing too. ESA's own documents give two different sets of masses for the pair.
What is written above is built from these numbers and quotes. Each row links to the page it was taken from. Get all of it as JSON, or ask our MCP server.
| What | Value |
|---|---|
| Coronagraph mass | 340 kg |
| Occulter mass | 200 kg |
| Coronagraph volume | 1100 x 1800 x 1700 mm |
| Occulter volume | 900 x 1400 x 900 mm |
| Occulting disk | 1400 mm diameter |
| Orbit | High Earth orbit, 19.7 h period |
| Formation length | approx. 150 m |
| Launch date | 5 December 2024 |
| Instrument | External coronagraph |
| Propulsion | mono-propellant thrusters (Coronagraph) |
| Power | deployable solar array (Coronagraph) |
Each material named in the sources: where it is used here, which other products use it, and its key numbers when its material page exists.
Used in 3 partsMain structure tube · Equipment box (EQB) · Helical antenna
Used in 2 partsOBA unit attachment fittings · Instrument support bipods (3)
Used in 1 partOuter thermal blanket (both spacecraft)
Used in 1 partOBA sandwich panels
Used in 1 partBatteries and solar cells
Used in 1 partPrimary objective lenses
The ESA page names only black MLI; eoPortal adds optical-bench sandwich panels, coronagraph structure alloy class, titanium bipods and an additively built antenna, but gives no alloys or part numbers.
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Outer thermal blanket (both spacecraft)“Both spacecraft are covered in black MLI to ensure maximum contrast with onboard LEDs” | black multi-layer insulation (film not named)multilayer-insulation-mli | — | — |
| Thermal control items“thermistors, heaters, radiators and thermal blankets” | thermistors, heaters, radiators and thermal blankets (materials not named) | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| OBA sandwich panels“high stability sandwich panels of CFRP and aluminum core” | CFRP and aluminum corecarbon-fibre | — | — |
| OBA unit attachment fittings“with titanium fittings for attachment of the Units” | titaniumtitanium | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Main structure tube“both in aluminum alloy” | aluminum alloy (alloy not stated)aluminium | — | — |
| Equipment box (EQB)“A structured parallelepiped called EQB (EQuipments Box)” | aluminum alloy (alloy not stated)aluminium | — | — |
| Instrument support bipods (3)“supported by three bipods in titanium” | titaniumtitanium | — | — |
| Primary objective lenses“composed of two separated lenses made of BK7G18 and SF6G05” | radiation hard glasses BK7G18 and SF6G05radiation-hard-glass | — | BK7G18, SF6G05 |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Helical antenna“a helical antenna that was printed with an aluminum alloy” | aluminum alloy (alloy not stated)aluminium | — | SENER Aeroespacial with CATEC |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Batteries and solar cells“Li-Ion batteries, battery regulated 28 V bus and triple-junction GaAs solar cells” | Li-Ion batteries; triple-junction GaAs solar cellslithium-ion-cell | — | — |
No structure panel materials for the two spacecraft bodies, no occulter disc material, no MLI film types, no fasteners or finishes, and no standards are given on the pages read.
Collected from public pages and documents, checked 4 Nov 2026.
Published · Updated
