August 24, 2025

On August 24,2025, ISRO accomplished first Integrated Air Drop Test (IADT-01) for Gaganyaan program at Satish Dhawan Space Centre (SDSC), Sriharikota. This test successfully demonstrated the objective of end to end performance validation of the critical parachute-based deceleration system of the Crew Module for Gaganyaan mission in one of the typical mission scenarios. This test is part of system level qualification of parachute-based deceleration system, in which a simulated CM, encompassing the deceleration system is dropped using a helicopter.

In Gaganyaan missions, parachute-based Deceleration system is employed during terminal phase of Crew Module (CM) descent to reduce the touchdown velocity of Crew Module to an acceptable limit for safe landing on sea. The parachute system and its layout, for IADT, was same as that of Gaganyaan missions. It comprised of four types of parachutes viz. Apex Cover Separation (ACS) (Ø 2.5 m - 2 nos), Drogue (Ø5.8 m - 2nos), Pilot (Ø3.4 m - 3 nos.) and Main parachutes (Ø 25 m - 3nos.).

In IADT-01, the simulated Crew module (~4.8 t) with Parachute system was released from an altitude of about 3 km using Indian Air Force's Chinook Heavy lift helicopter. The deceleration system initiation began with firing of ACS Mortar which deploys the Ø2.5 m ACS parachutes, which is followed by the separation of Apex cover. The deployed ACS parachutes then decelerated the Apex cover and prevented it from re-contacting the descending simulated CM during the test. The Ø5.8 m Drogue parachutes were then deployed using Drogue Mortar, which provided first stage deceleration to the simulated crew module. After first stage deceleration, the Drogue parachutes were released using pyro-based parachute releasers. This was followed by firing of three Pilot Mortars, which ejected and deployed the Ø3.4 m Pilot parachutes., which then independently extracted and deployed the three Main parachutes of Ø25 m diameter.

Further, main parachutes reduced the terminal velocity of the simulated Crew Module to about 8m/s. After touchdown, the Main parachutes were released using parachute releasers. These parachutes totaling ten in number deployed in a precise sequence to gradually decrease the velocity of the Crew Module for safe touchdown.

The test simulated a possible abort scenario on the launch pad. Upon release of CM, the onboard avionics commanded for deceleration system initiation and there after parachutes deployed in predefined sequence. During this test, onboard avionics systems were also used to measure various parameters, which were telemetered to ground as well as stored onboard using Solid State Data Recorder (SSDR). Post splashdown, the simulated Crew Module was successfully recovered and ferried back on INS Anvesha to Chennai port.

Extensive modeling of CM as well as helicopter was carried out to address the dynamics of underslung body. Besides this, extensive trials with a dummy crew module hardware and IAF’s Chinook Helicopter were carried out to validate the mission profile and related standard operating procedures. Following successful accomplishment of multiple trial sorties and clearance by Test Authorisation Board (TAB), IADT-01 was carried out with the actual test article. Apart from ISRO centres, other governmental agencies including DRDO, Indian Air Force, Indian Navy and Indian Coast Guard also contributed in the successful accomplishment of this major test. Similar tests at different deployment conditions are planned in forthcoming days.