Polar Satellite Launch Vehicle (PSLV) — Interactive LMS Simulator
Explore PSLV architecture, launch sequence, propulsion stages and mission concepts through an interactive 16:9 learning experiment.
Aim
To study the configuration and working sequence of the Polar Satellite Launch Vehicle (PSLV), identify its major stages and payload section, and visualize the key phases of a conceptual satellite launch mission.
Payload fairing, PS4, PS3, PS2, PS1 and strap-on boosters.
Why multistage launch vehicles discard spent stages during ascent.
Altitude, velocity, acceleration, thrust and vehicle-mass trends during a conceptual mission.
Theory — PSLV & PSLV-XL
Polar Satellite Launch Vehicle (PSLV) is the third-generation launch vehicle of India and the first Indian launch vehicle equipped with liquid stages. Its combination of solid and liquid propulsion, selectable strap-on configurations, multiple-satellite accommodation and multiple-orbit capability has established PSLV as the “Workhorse of ISRO.”
Vehicle & Payload Specifications
Height: 44–44.4 m
Diameter: 2.8 m
Stages: 4
Lift-off mass: 320 t (XL)
First flight: 20 September 1993
CA: no strap-ons
DL: 2 strap-ons
QL: 4 strap-ons
XL: 6 strap-ons
SSPO: up to 1,750 kg at about 600 km
Sub-GTO: about 1,425 kg
Supports multiple-satellite and multiple-orbit missions.
Four-Stage Propulsion Architecture
Type: Solid
Fuel: HTPB
Max thrust: 4,800 kN
Provides high initial thrust for lift-off and early atmospheric ascent.
Type: Solid
Fuel: HTPB
Max thrust: 719 kN each
Augment PS1 thrust during the high-mass early-flight phase.
Type: Liquid
Fuel: UDMH + N₂O₄
Max thrust: 799 kN
Continues controlled acceleration after the first-stage phase.
Type: Solid
Fuel: HTPB
Max thrust: 240 kN
Provides upper-stage high thrust after the major atmospheric phase.
Type: Liquid
Fuel: MMH + MON
Max thrust: 7.3 × 2 kN
Provides accurate final velocity shaping and orbital injection.
Protects payloads from aerodynamic, acoustic and thermal environments. Multi-payload adaptors enable several spacecraft to be accommodated for deployment.
Why Solid → Liquid → Solid → Liquid?
PSLV combines the complementary characteristics of propulsion systems. Solid motors provide high thrust with relatively simple propulsion hardware, while liquid stages provide controllable propulsion useful for trajectory shaping. Thus PS1 → PS2 → PS3 → PS4 combines strong early acceleration with increasingly precise upper-stage mission control.
Strap-ons are not extra stages
PSLV-XL uses six S12 strap-on motors around PS1, but PSLV remains a four-stage vehicle. Strap-ons are auxiliary first-stage thrust devices rather than six additional sequential stages. The family uses different booster counts to tailor early-flight performance: XL = 6, QL = 4, DL = 2, CA = 0.
Multiple Satellites & Multiple Orbits
PSLV can carry several spacecraft using multi-payload adaptors. Mission flexibility depends on payload accommodation together with guidance, staging, vehicle orientation and upper-stage velocity management. This allows mission planners to satisfy different spacecraft deployment requirements rather than merely releasing every payload at the same instant.
Workhorse of ISRO
After its first successful launch in October 1994, PSLV developed a long record of missions to Low Earth Orbit, particularly Sun-Synchronous Polar Orbit. It also launched Chandrayaan-1 (2008) and the Mars Orbiter Spacecraft (2013), which subsequently travelled toward the Moon and Mars. PSLV-C48 marked the 50th PSLV launch.
Why Staging Matters
After a stage consumes its propellant, its tanks, casing and propulsion hardware become largely inert mass. Separating that stage prevents the remaining vehicle from accelerating unnecessary mass, improving the usable mass ratio and supporting the velocity increment required for orbit.
Core Launch-Vehicle Relations
Because propellant consumption reduces vehicle mass, acceleration may rise even when thrust does not increase. Actual flight acceleration also depends on changing thrust, drag, gravity, staging and trajectory orientation.