# PSLV fourth stage (PS4) 3D model

> Shape built from published dimensions and pictures; details simplified.

Free 3D model of PSLV fourth stage (PS4), a rocket stage, built from published dimensions by Space Radar. 12,800 triangles, 94 kB glTF, MIT.

- **Class:** Rockets and stages
- **Mission:** Launch vehicles
- **Triangles:** 12,800
- **File:** pslv-ps4.glb, 94 kB, glTF 2.0 binary (meshopt)
- **Look:** Physically based
- **Size:** 3.7 m across
- **Made:** Built from dimensions
- **Added:** 2026-11-04
- **Download:** https://raw.githubusercontent.com/Sara-Managed-Projects/space-radar/main/site/models/pslv-ps4.glb
- **Mirror:** https://git.sara-agent.org/sara-projects/space-radar/raw/branch/main/site/models/pslv-ps4.glb
- **Viewer:** https://www.spaceradar.ai/model/?id=pslv-ps4
- **Licence:** MIT (https://github.com/Sara-Managed-Projects/space-radar/blob/main/LICENSE)
- **Credit:** PSLV fourth stage (PS4) 3D model by Space Radar (spaceradar.ai), MIT License

Canonical: https://models.spaceradar.ai/pslv-ps4/

## How it was made

Built in code from published dimensions and photographs, with no image-to-3D generator and no one else’s mesh. 3D model: built by Space Radar from published dimensions and ISRO's photographs of the stage (GODL-India), compared with them.

built by this project in code (tools/stage-builder/, stages.py `pslv_ps4`, rebuilt in release 1.8.0; first built and held in release 1.4.0); no image-to-3D model was used and no published mesh: none of NASA 3D Resources' paths is this stage and ISRO publishes none (read 2026-11-04)

## Dimensions

- Tank diameter: 1.34 m
- Ring diameter: 2.8 m
- Length: 3.74 m
- Engines: 2
- Engine thrust: 7.4 kN
- Propellant: 2500 kg

Source: Wikipedia, 'Polar Satellite Launch Vehicle', section 'Fourth stage (PS4)' (CC BY-SA 4.0; OPENED 2026-11-04): 'powered by regeneratively cooled twin engines, burning monomethylhydrazine (MMH) and mixed oxides of nitrogen (MON). Each pressure fed engine generates 7.4 kN', 'The stage is pressurized by helium and carries 1,600 kg to 2,500 kg of propellant depending on the mission requirements. PS4 has three variants L1.6, L2.0 and L2.5'; the same article: the third stage has 'a Kevlar-polyamide fibre case', and during the combined coast 'burnt-out PS3 remains attached to PS4' (which is why the gold Kevlar case and the nozzle hang under the stage in ISRO's photographs). The 1.34 m tank and the 2.9 to 3.0 m length of the stage proper are the numbers the 1.4.0 build quoted from ISRO's PSLV-C55 mission brief (NOT opened again on 2026-11-04; they are consistent with 2 500 kg of MMH and MON-3 in a 1.34 m tank with a 1.3 m barrel, a cross-check that is ours). THE 2.8 m RING is the PSLV's standard 2.8 m core diameter (the same article, 'first stage': 'The 2.8 m diameter motor case') and agrees with the photographs, where the ring is 1.4 times the width of the 2.0 m third-stage case. NOT CITED, READ OFF THE PHOTOGRAPHS AND ESTIMATED against those two widths: the skirt's height (0.9 m) and its 2.0 m lower end, the ring (0.35 m), the struts (0.6 m), the platform, the heights of the barrel (1.3 m) and the dome (0.4 m), the helium spheres (0.46 m, four), the boxes, the harness, the adapter ring. NOT SEEN IN ANY PICTURE and drawn only because the stage has them: the two L-2-5 engines under the tank, inside the skirt (their size is ours). THE PICTURES DISAGREE about the skirt: the 2008 photograph stands the stage on a brown ribbed drum (a handling fixture, not drawn); the 2019 and 2023 photographs hang it from a black ribbed cone under the ring (drawn). Whether that cone stays with the stage in orbit no opened page says. The stage's tank is a 2 500 kg one (L2.5); the L1.6 and L2.0 stages have a shorter tank.

## References

- [PSLV-C11 Fourthstage.jpg (ISRO)](https://commons.wikimedia.org/wiki/File:PSLV-C11_Fourthstage.jpg), Indian Space Research Organisation (GODL-India (Commons LicenseShortName, read 2026-11-04): looked at, nothing taken from it)
- [PSLV-C44 Third and Fourth stages at Stage Preparation Facility.jpg (ISRO)](https://commons.wikimedia.org/wiki/File:PSLV-C44_Third_and_Fourth_stages_at_Stage_Preparation_Facility.jpg), Indian Space Research Organisation (GODL-India (Commons LicenseShortName, read 2026-11-04): looked at, nothing taken from it)
- [PSLV-C55, TeLEOS-2 - Third and fourth stage combined stack being integrated with interstage.webp (ISRO)](https://commons.wikimedia.org/wiki/File:PSLV-C55,_TeLEOS-2_-_Third_and_fourth_stage_combined_stack_being_integrated_with_interstage.webp), Indian Space Research Organisation (GODL-India (Commons LicenseShortName, read 2026-11-04): looked at, nothing taken from it)
- [PSLV-C52, EOS-04 (aka RISAT-1A) - Assembled third stage (PS3) and fourth stage (PS4) stack being hoisted.jpg (ISRO)](https://commons.wikimedia.org/wiki/File:PSLV-C52,_EOS-04_(aka_RISAT-1A)_-_Assembled_third_stage_(PS3)_and_fourth_stage_(PS4)_stack_being_hoisted.jpg), Indian Space Research Organisation (GODL-India (Commons LicenseShortName, read 2026-11-04): looked at, nothing taken from it)
- [PSLV-C54, EOS-6 (aka Oceansat-3) - Oceansat-3 on PSLV fourth stage.webp (ISRO)](https://commons.wikimedia.org/wiki/File:PSLV-C54,_EOS-6_(aka_Oceansat-3)_-_Oceansat-3_on_PSLV_fourth_stage.webp), Indian Space Research Organisation (GODL-India (Commons LicenseShortName, read 2026-11-04): looked at, nothing taken from it)