Session
Launch & Propulsion
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
Vyom 2U is a compact 2U green monopropellant propulsion system designed to deliver a total impulse of 1700 Ns. At Beginning-of-Life (BOL) conditions, corresponding to a tank pressure of 24 bar, the thruster can deliver up to 1.1 N with a specific impulse of approximately 250 s, while requiring a peak electrical power of 15 W. At an operating pressure of 14 bar, the propulsion system delivers a thrust of approximately 0.67 N with a specific impulse of about 238 s. This operating point was deliberately selected for in-orbit operations to maintain sub-newton thrust levels compatible with the attitude control authority and disturbance limits of the POEM platform. It uses a monopropellant blend commercially called as MS289, which comprises of 53 Wt% hydrogen peroxide and 12 Wt% ethanol blended with special mix of stabilizers in deionized water (35 Wt%) as a desensitizing agent, making it completely safe for range-safety operations at launch site and promising high specific impulse of >250 s in space. Propellant loading and pressurization of MS289 in Vyom 2U propulsion system was carefully conducted by a team of experts at the Spacecraft Preparation Bay located in Satish Dhawan Space Centre (SDSC) at Sriharikota under stringent safety protocols without the use of SCAPE suits and with minimal PPEs. The Vyom 2U propulsion system was launched on 30th December 2024 onboard PSLV-C60 for a demonstrative mission aboard the PS4-Orbital Experiment Module-4 (POEM-4) platform in Low Earth Orbit. The propulsion system was successfully commissioned after the platform reached a stable orbit of 350 km and telemetry data provided a clear indication that all subsystems of the propulsion system were operating nominally.
On New Year’s Eve, the Vyom 2U propulsion system successfully performed its first in-orbit firing aboard POEM-4, generating an angular velocity of 0.5 degrees per second along the yaw axis before onboard control systems restored stability. Over the next 71 days, the system was thoroughly tested, with the thruster fired cumulatively for over 620+ seconds across 23 on/off cycles, followed by safe passivation of the pressuring gas before initiating deorbiting. Throughout this period, all subsystems including MS289 propellant exhibited nominal behavior during periodic health checks, confirming the system’s reliability in orbit. Performance was evaluated using three datasets: onboard propulsion telemetry (pressure and temperature), IMU-based body rate data from the POEM-4 platform during thruster operation, and ground test results from a replica flight model tested on a thrust stand in a high-altitude facility. As inertial parameters of the POEM-4 platform were not precisely known, direct thrust measurement in orbit was not possible. Instead, thrust and performance metrics such as specific impulse and total impulse were reconstructed by correlating ground test data with in-orbit observations. This paper presents insights from the ground and flight demonstration phases, highlighting the methodologies used for performance reconstruction and key lessons learned from the demonstration mission.
Document Type
Event
Presentation
Included in
In-Orbit Demonstration of the Vyom-2U: A Green Monopropellant-Based Propulsion System Onboard ISRO's PSLV C60 POEM-4
Salt Palace Convention Center, Salt Lake City, UT
Vyom 2U is a compact 2U green monopropellant propulsion system designed to deliver a total impulse of 1700 Ns. At Beginning-of-Life (BOL) conditions, corresponding to a tank pressure of 24 bar, the thruster can deliver up to 1.1 N with a specific impulse of approximately 250 s, while requiring a peak electrical power of 15 W. At an operating pressure of 14 bar, the propulsion system delivers a thrust of approximately 0.67 N with a specific impulse of about 238 s. This operating point was deliberately selected for in-orbit operations to maintain sub-newton thrust levels compatible with the attitude control authority and disturbance limits of the POEM platform. It uses a monopropellant blend commercially called as MS289, which comprises of 53 Wt% hydrogen peroxide and 12 Wt% ethanol blended with special mix of stabilizers in deionized water (35 Wt%) as a desensitizing agent, making it completely safe for range-safety operations at launch site and promising high specific impulse of >250 s in space. Propellant loading and pressurization of MS289 in Vyom 2U propulsion system was carefully conducted by a team of experts at the Spacecraft Preparation Bay located in Satish Dhawan Space Centre (SDSC) at Sriharikota under stringent safety protocols without the use of SCAPE suits and with minimal PPEs. The Vyom 2U propulsion system was launched on 30th December 2024 onboard PSLV-C60 for a demonstrative mission aboard the PS4-Orbital Experiment Module-4 (POEM-4) platform in Low Earth Orbit. The propulsion system was successfully commissioned after the platform reached a stable orbit of 350 km and telemetry data provided a clear indication that all subsystems of the propulsion system were operating nominally.
On New Year’s Eve, the Vyom 2U propulsion system successfully performed its first in-orbit firing aboard POEM-4, generating an angular velocity of 0.5 degrees per second along the yaw axis before onboard control systems restored stability. Over the next 71 days, the system was thoroughly tested, with the thruster fired cumulatively for over 620+ seconds across 23 on/off cycles, followed by safe passivation of the pressuring gas before initiating deorbiting. Throughout this period, all subsystems including MS289 propellant exhibited nominal behavior during periodic health checks, confirming the system’s reliability in orbit. Performance was evaluated using three datasets: onboard propulsion telemetry (pressure and temperature), IMU-based body rate data from the POEM-4 platform during thruster operation, and ground test results from a replica flight model tested on a thrust stand in a high-altitude facility. As inertial parameters of the POEM-4 platform were not precisely known, direct thrust measurement in orbit was not possible. Instead, thrust and performance metrics such as specific impulse and total impulse were reconstructed by correlating ground test data with in-orbit observations. This paper presents insights from the ground and flight demonstration phases, highlighting the methodologies used for performance reconstruction and key lessons learned from the demonstration mission.
