EnduroSat makes aluminium CubeSat frames in four sizes, from 1U to 6U, tested for vibration and thermal vacuum.
endurosat-cubesat-structures EnduroSat sells aluminium CubeSat frames in four sizes: 1U, 1.5U, 3U and 6U. NASA's 2021 chapter on structures reports vibration, thermal and thermal-vacuum testing, and says the 1U and 3U frames have flown. EnduroSat says more than 590 of its CubeSat structures are now in orbit.
NASA's table names the metal for each size. The 3U and 6U frames are 6061 aluminium, and the 1U and 1.5U are given as 6061 or 7075. A 2022 design paper for the student CubeSat 3UCubed describes the 3U kit in more detail: a hard-anodised frame, brass rods that carry the circuit boards, and 304 stainless-steel screws and nuts.
Commercial CubeSat frames in 1U, 1.5U, 3U and 6U sizes, with vibration and thermal-vacuum qualification and flight heritage on the 1U and 3U. A qualified structure shortens the path to a launch-ready satellite.
The 1U frame measures 100 by 100 by 114 millimetres. The 3U is 100 by 100 by 340 and the 6U is 100 by 226 by 366. NASA's table puts the 1U frame's mass under 0.1 kilogram and the 6U's under 1 kilogram.
The paper says the 3U kit comes as a PC/104 base with rods, a frame, mid supports, a top plate and securing hardware. The frame is hard-anodised 6061 aluminium. The brass rods carry the board stack and help conduct heat.
The 3U kit comes with separation switches, and roller switches on the rails are optional. The screws and nuts are 304 stainless steel. Wide openings in the frame suited 3UCubed, whose instrument needed a clear 45-degree view, and they make solar panels easy to fit.
The 3U and 6U frames, and one of two options for the 1U and 1.5U. The 3U frame is hard anodised.
The other option for the 1U and 1.5U frames. The temper is not given.
The mounting rods in the 3U kit, chosen for efficient heat conduction.
The screws and nuts that hold the 3U structure together.
On its page for the larger 8U frame, EnduroSat states full compliance with PC/104 and the CubeSat standard. The one flight tied to the 3U frame is 3UCubed. The paper says its team chose the frame at the design stage and fitted EnduroSat solar panels with Azur Space cells. 3UCubed launched on a SpaceX Falcon 9 from Vandenberg on 28 November 2025.
The team chose the EnduroSat COTS 3U structure at preliminary design (2022 paper); the flight article's structure is not re-confirmed in the launch pages
EnduroSat's test pod simulates a P-POD for vibration tests; no flight deployer compatibility list is published for the 1U to 6U structures
Interface standard; EnduroSat claims PC104 and CubeSat Standard compliance
NASA CubeSat Launch Initiative
Reference for the CubeSat Design Specification and dispensers; the guide does not name this product
Solar cells on the EnduroSat panels fitted to the 3UCubed structure
NASA Ames
Aluminium alloy 6061. Here: 3U structure; 6U structure and more. There: EnduroSat 3U structure; ISISPACE 3U structure and more.
Aluminium alloy 7075-T6. Here: EnduroSat structures (all sizes); 1U structure and more. There: EnduroSat structures (1U to 6U); EnduroSat 1U structure and more.
Anodized aluminium. Here: Hard-anodized pearl finish. There: Dispenser-compatible rails.
PSAS / Oregon State
Aluminium alloy 6061. Here: 3U structure; 6U structure and more. There: 1U +X frame; Card wedge (card clamp) and more.
Anodized aluminium. Here: Hard-anodized pearl finish. There: 1U +X frame (anodize); Card wedge (anodize) and more.
Gallium arsenide. Here: Body-mounted solar panels (1U, 1.5U, 3U sizes) with triple-junction cells. There: Solar cell (SpectraLabs XTE-SF, 2 per module); Solar cell technology.
Blackwing Space
Aluminium alloy 6061. Here: 3U structure; 6U structure and more. There: Sparrow 1U Chassis; Sparrow 1U XL Chassis and more.
Gallium arsenide. Here: Body-mounted solar panels (1U, 1.5U, 3U sizes) with triple-junction cells. There: Draft solar panel cells (triple-junction GaAs).
Blackwing Space
Aluminium alloy 6061. Here: 3U structure; 6U structure and more. There: Kestrel 3U XL Chassis; Structure (all platforms table).
Gallium arsenide. Here: Body-mounted solar panels (1U, 1.5U, 3U sizes) with triple-junction cells. There: Draft solar panel cells (triple-junction GaAs).
Blackwing Space
Aluminium alloy 6061. Here: 3U structure; 6U structure and more. There: Osprey 6U XL Chassis; Structure (all platforms table).
Gallium arsenide. Here: Body-mounted solar panels (1U, 1.5U, 3U sizes) with triple-junction cells. There: Draft solar panel cells (triple-junction GaAs).
NASA CubeSat Launch Initiative
Aluminium alloy 6061. Here: 3U structure; 6U structure and more. There: CubeSat structure; CubeSat structure (template row 2, body type Box).
Anodized aluminium. Here: Hard-anodized pearl finish. There: Rails (deployer interface rails).
EnduroSat's own pages for these four sizes are no longer on its website, so the details come second-hand from NASA and a design paper. The anodising specification, fastener count, tolerances, loads, temperatures and compatible dispensers aren't published. The two sources give different masses for the 3U frame. Launch reports don't say which structure flew on 3UCubed.
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 |
|---|---|
| Sizes offered | 1U, 1.5U, 3U, 6U |
| Qualification | Environmental qualification including vibration, thermal and TVAC |
| Flight heritage | 1U and 3U structures |
| 3U dimensions | 100 x 100 x 340 mm |
| 1U dimensions | 100 x 100 x 114 mm (table also lists < 0.1 kg) |
| 1.5U dimensions | 100 x 100 x 170.2 mm |
| 6U dimensions | 100 x 226 x 366 mm |
| 1U structure mass (NASA table) | less than 0.1 kg |
| 1.5U structure mass (NASA table) | 0.11 kg |
| 3U structure mass (NASA table) | less than 0.29 kg |
| 6U structure mass (NASA table) | less than 1 kg |
| 8U structure | 100 x 226.3 x 454 mm, 973 g, Aluminium 6082 |
| 16U structure | 226.3 x 226.3 x 454 mm, 2.5 kg, Aluminium 6082 |
| CubeSat structures in orbit (maker claim) | 590+ |
| Qualification of the 3U structure (paper) | vibration, shock, thermal vacuum per NASA GEVS GSFC-STD-7000 |
| CDS Rev 14.1: rail minimum width | 8.5 mm, measured from the rail edge to the first protrusion |
| CDS Rev 14.1: rail surface roughness | less than 1.6 micrometres (a 'should') |
| CDS Rev 14.1: rail edge radius | at least 1 mm (a 'should') |
| CDS Rev 14.1: rail end contact area | 6.5 mm x 6.5 mm minimum on the +/- Z face |
| CDS Rev 14.1: protrusion limit | 6.5 mm normal to the surface from the plane of the rail |
| CDS Rev 14.1: rail contact with dispenser | at least 75% of the rail |
| CDS Rev 14.1: structure material | aluminium alloy; 7075, 6061, 6082, 5005 and/or 5052 typical |
| CDS Rev 14.1: rail surface finish | hard anodized wherever it touches the dispenser rails |
| CDS Rev 14.1: maximum mass per size | 1U 2.00 kg, 1.5U 3.00 kg, 2U 4.00 kg, 3U 6.00 kg, 6U 12.00 kg, 12U 24.00 kg |
| CDS Rev 14.1: separation spring guideline | max force below 6.7 N (1.5 lbf), stroke above 2.5 mm |
| CDS Rev 14.1: deployment switch | at least one, actuated while the CubeSat is in the dispenser |
| CDS Rev 14.1: outgassing | TML at most 1.0 % and CVCM at most 0.1 % |
| CDS Rev 14.1: remove-before-flight pin | required; protrudes no more than 6.5 mm from the rail surface when fully inserted |
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 parts3U structure · 6U structure · Frame
Used in 3 parts8U frame · 16U frame · CubeSat Test Pod (6U to 16U)
Used in 3 partsEnduroSat structures (all sizes) · 1U structure · 1.5U structure
Used in 1 partHard-anodized pearl finish
Used in 1 partMounting rods
Used in 1 partBody-mounted solar panels (1U, 1.5U, 3U sizes) with triple-junction cells
Used in 1 partSecuring hardware (screws, nuts)
The only usable source is a NASA State-of-the-Art table that names an aluminium alloy per frame size; EnduroSat's own structure pages returned no content. Components, suppliers and links were added from public sources. A material is left blank where no source states it.
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| EnduroSat structures (all sizes)“all EnduroSat structures are made of either Aluminum 6061-T651 or Al 7075” | Aluminum 6061-T651 or Al 7075aluminium-7075 | — | — |
| 1U structure“1U 100 x 100 x 114 < 0.1 Al 6061 or 7075” | Al 6061 or 7075aluminium-7075 | — | — |
| 1.5U structure“1.5U 100 x 100 x 170.2 0.11 Al 6061 or 7075” | Al 6061 or 7075aluminium-7075 | — | — |
| 3U structure“3U 100 x 100 x 340 < 0.29 Al 6061” | Al 6061aluminium-6061 | — | — |
| 6U structure“6U 100 x 226 x 366 <1 Al 6061” | Al 6061aluminium-6061 | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| PC/104 baseBase of the 3U structure, to which the rods and frame attach“comes as PC/104 base with rods, frame, mid supports, top plate, and securing hardware” | Not said | — | Supplier: EnduroSat |
| Mounting rodsCarry the PC/104 board stack and conduct heat“brass mounting rods for efficient heat conduction” | Brass (alloy not stated)brass | — | Supplier: EnduroSat |
| FramePrimary frame of the 3U structure, hard anodized“hard anodized space- grade 6061 aluminum” | Aluminium 6061, hard anodized (paper; NASA table lists Al 6061 for the 3U)aluminium-6061 | — | Supplier: EnduroSat |
| Mid supportsIntermediate supports for the board stack“comes as PC/104 base with rods, frame, mid supports, top plate, and securing hardware” | Not said | — | Supplier: EnduroSat |
| Top plateCloses the +Z end of the structure“comes as PC/104 base with rods, frame, mid supports, top plate, and securing hardware” | Not said | — | Supplier: EnduroSat |
| Securing hardware (screws, nuts)Fasteners that hold the structure together“304 stainless-steel securing hardware” | Stainless steel 304stainless-304 | — | Supplier: EnduroSat |
| Separation switchesDeployment switches supplied with the structure“comes with separation switches and optional roller switches on the rails” | Not said | — | Supplier: EnduroSat |
| Roller switches on the rails (optional)Optional rail-mounted switches“comes with separation switches and optional roller switches on the rails” | Not said | — | Supplier: EnduroSat |
| Wide openings in the frameOpen side faces that let an instrument see 45 degrees without obstruction and make solar panel fitting easy“the availability of wide openings that accommodate the 45° of unobstructed FoV required by the instrument” | Not said | — | — |
| Exploded-view drawing in the 3U datasheetShows the structure parts; used as Figure 12 of the paper“Exploded view EnduroSat 3U Structure, from datasheet” | Not said | — | — |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| 8U framePrimary frame for 8U CubeSats, assembled vertically or horizontally“Simple modular design for easy assembly both vertically and horizontally” | Aluminium 6082aluminium-6082 | — | Supplier: EnduroSat |
| Mounted rings (x6)Stiffening rings that are counted in the structure mass“973 g (including screws, kill switches, 6 mounted rings)” | Not said | — | Supplier: EnduroSat |
| Kill switches (1 or 2; option of four)Deployment (kill) switches mounted in the rail feet“Four kill switches option” | Not said | — | Supplier: EnduroSat |
| ScrewsFasteners included in the structure mass“973 g (including screws, kill switches, 6 mounted rings)” | Not said | — | Supplier: EnduroSat |
| Hard-anodized pearl finishSurface finish of the frame and rails“Pearl-finished & hard anodized” | Aluminium 6082, hard anodized (pearl finish)anodized-aluminium | — | Supplier: EnduroSat |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| 16U framePrimary frame for 16U CubeSats“226.3 x 226.3 x 454 mm” | Aluminium 6082aluminium-6082 | — | Supplier: EnduroSat |
| Kill switches (1 or 2)Deployment (kill) switches“1/2 KILL SWITCHES” | Not said | — | Supplier: EnduroSat |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Rails (hard anodized, CDS interface)Contact surfaces that slide in the dispenser; the CDS sets width, finish and contact area (see extra specs)“comes with separation switches and optional roller switches on the rails” | Not said | — | Supplier: EnduroSat |
| Part | Material | Finish and standard | Made by |
|---|---|---|---|
| Body-mounted solar panels (1U, 1.5U, 3U sizes) with triple-junction cellsEnduroSat solar panels used on the 3UCubed 3U structure“COTS solar panels from EnduroSat comprising highly efficient Azur Space 3G30A triple junction solar cells with up to 30% efficiency” | Gallium arsenide (Azur Space 3G30A triple-junction cells)gallium-arsenide | — | Supplier: EnduroSat |
| CubeSat Test Pod (6U to 16U)Ground vibration test fixture with optional separation springs; not a flight deployer“Capacity for 6U to 16U CubeSats for vibrational testing” | Aluminium 6082aluminium-6082 | — | Supplier: EnduroSat |
All data is second-hand (NASA SOA 2021, which cites EnduroSat 2017); EnduroSat's own 1U/1.5U/3U/6U pages were not retrievable (the product URLs returned the site's 404 page). No temper for 7075, no finish/anodize, no fastener material, no parts list. The NASA text gives 'either 6061-T651 or 7075' for the family but the table narrows 3U and 6U to Al 6061 without saying which applies to a given order. EnduroSat's current 8U and 16U structure pages (not this product) state 'Aluminum 6082' and a hard-anodized surface, so the maker may use different alloys for larger frames; those are not recorded as parts here. More detail: EnduroSat's own 1U, 1.5U, 3U and 6U product pages are no longer on the live site (they redirect to the structures category page, which lists only the 8U and 16U), so per-part data for the 1U to 6U sizes comes from the NASA 2021 table and the 3UCubed paper. Not published in what was read: temper of the 7075 option, anodize specification, kill-switch and separation-spring part numbers and count per size, fastener count, rail dimensions and tolerances beyond the CDS, dispenser (P-POD, NRCSD, ISIPOD, EXOpod) compatibility list, and the datasheet and CAD files (behind a form). The maker's 8U and 16U pages give Aluminum 6082 while the NASA table and the 3UCubed paper give 6061 for the smaller sizes. Satellites that flew: only 3UCubed is tied to the EnduroSat 3U structure, and only by the 2022 design paper. More detail: EnduroSat's own 1U, 1.5U, 3U and 6U product pages are no longer on the live site (they redirect to the structures category page, which lists only the 8U and 16U), so per-part data for the 1U to 6U sizes comes from the NASA 2021 table and the 3UCubed paper. Not published in what was read: temper of the 7075 option, anodize specification, kill-switch and separation-spring part numbers and count per size, fastener count, rail dimensions and tolerances beyond the CDS, dispenser (P-POD, NRCSD, ISIPOD, EXOpod) compatibility list, and the datasheet and CAD files (behind a form). The maker's 8U and 16U pages give Aluminum 6082 while the NASA table and the 3UCubed paper give 6061 for the smaller sizes. Satellites that flew: only 3UCubed is tied to the EnduroSat 3U structure, and only by the 2022 design paper.
RAX-1, built on the kit 
Ex-Alta 2 flight hardware 
Collected from public pages and documents, checked 4 Nov 2026.
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