Successful Hot Test of Gaganyaan Service Module Propulsion System – System Demonstration Model (SDM)

MAHENDRAGIRI, India (ISRO PR) — On August 28, 2021, ISRO successfully conducted the first hot test of the System Demonstration Model (SDM) of the Gaganyaan Service Module Propulsion System for a duration of 450 seconds at the test facility of ISRO Propulsion Complex (IPRC), Mahendragiri, Tamil Nadu.

The system performance met the test objectives and there was a close match with the pre-test predictions. Further, a series of hot tests are planned to simulate various mission conditions as well as off-nominal conditions.

The Service Module is part of the Gaganyaan Orbital module and is located below the crew module and remains connected to it until re-entry. The Service Module (SM) Propulsion System consists of a unified bipropellant system consisting of 5 nos. of 440 N thrust engines and 16 nos. of 100 N Reaction Control system (RCS) thrusters with MON-3 and MMH as Oxidizer and Fuel respectively.

The System Demonstration Model (SDM), consisting of 5 nos. of 440 N engines and 8 nos. of 100 N thrusters, was realized to qualify the propulsion system performance in ground. A new test facility is established at IPRC, Mahendragiri for testing the SDM.

One response to “Successful Hot Test of Gaganyaan Service Module Propulsion System – System Demonstration Model (SDM)”

1. gunsandrockets says:

   August 30, 2021 at 3:07 am

   0

   0

   Mixed oxides of nitrogen (MON) are solutions of nitric oxide (NO) in dinitrogen tetroxide/nitrogen dioxide (N2O4 and NO2). It may be used as an oxidizing agent in rocket propulsion systems.[1] A broad range of compositions is available, and can be denoted as MONi, where i represents the percentage of nitric oxide in the mixture (e.g. MON3 contains 3% nitric oxide, MON25 25% nitric oxide). An upper limit is MON40 (40% by weight). In Europe MON 1.3 is mostly used for rocket propulsion systems, while NASA seems to prefer MON 3. A higher percentage of NO decreases the corrosiveness and oxidation potential of the liquid, but increases costs.

   The addition of nitric oxide also reduces the freezing point to a more desirable temperature. The freezing point of pure nitrogen tetroxide is −9 °C (16 °F), while MON3 is −15 °C (5 °F) and MON25 is −55 °C (−67 °F).[2]

   Log in to Reply