# Test Vehicle Abort Mission-1

Test Vehicle Abort Mission-1 (TV-D1) was a high altitude abort test performed as part of the Gaganyaan program, initially set to be held on 21 October 2023 at around 02:30 UTC (08:00 IST). Liftoff was delayed to 03:15 UTC due to weather issues, and five seconds before launch it was put on hold by the on-board computer due to an engine anomaly, as reported in ISRO's mission livestream. The launch occurred at 04:30 UTC, and the crew module successfully separated from the launch vehicle. The crew module was successfully recovered by the Indian Navy. India is the fourth country, after Russia, the United States, and China, to successfully test this technology.

## Background

In April 2022, it was proposed that both demonstration missions should have a depressurized crew module. On 10 August 2022 ISRO performed a successful static test of the Crew Escape System (CES). The crew module fairing and the high altitude abort engine were delivered by Hindustan Aeronautics Limited on 18 August 2022. In December 2022, the structural qualification test for the crew module fairing with grid fins was successfully completed for the TV-D1 configuration. In August 2023, the rocket was ready at Sriharikota and the test was scheduled for late September. TV-D1 is the first development flight from the Gaganyaan program. Gaganyaan-1, the first orbital test flight, is planned to take place in 2024.
The crew module used for TV-D1, was an unpressurised version that had completed its integration testing. This unpressurised module was required to have an overall size and mass of an actual Gaganyaan crew module, and housed all systems required for deceleration and recovery, including a complete set of parachutes, recovery aids actuation systems, and pyros. The avionics systems operate in a dual-redundant mode for navigation, sequencing, telemetry, instrumentation, and power. The crew module in this mission was extensively instrumented to capture the flight data for evaluation of the performance of various systems. The crew module was planned to be recovered after touchdown in the Bay of Bengal using a dedicated vessel and diving team from the Indian Navy.
With a rocket based upon the GSLV L40 stage, TV-D1 was to be launched up to 11 km above sea level, where an in-flight abort scenario would be initiated. The capsule was expected to then continue another 4–5 km. The mission aimed to test the CES's separation from the rocket, ability to maintain a trajectory leading to a safe distance, and eventual parachute deployment.

## Mission objectives

* Flight demonstration and evaluation of the test vehicle subsystems
* Flight demonstration and evaluation of the CES, including various separation systems
* Crew Module characteristics and demonstration of deceleration systems at higher altitude and its recovery

## Results

The launch occurred at 04:30 UTC, and was tracked by ground teams at Sriharikota. The crew module successfully separated from the launch vehicle and was recovered by the INS Shakthi in the Bay of Bengal despite rough seas.

## Timeline

Sequence of flight events :
| Time | Event |
| TV Event ||
| -3.4 | Engine Ignition |
| +58.1 | Pill Box Achieved |
| +58.5 | Engine Cutoff |
| +60.9 | TV-CES Sep |
| CES Event ||
| +60.9 | CMF•CSIA Sep |
| +60.9 | CM•SM Sep |
| +60.9 | HEM P+ Motor Ignition |
| +60.9 | HEM P• Motor Ignition |
| +60.9 | HEM Y+ Motor Ignition |
| +60.9 | HEM Y• Motor Ignition |
| +61.5 | CRID FIN-3 Deploy |
| +61.5 | CRID FIN-4 Deploy |
| +61.6 | CRID FIN-2 Deploy |
| +61.8 | CRID FIN-1 Deploy |
| +90.9 | CM•CES Sep |
| +90.9 | CJM Ignition |
| CM Event ||
| +0.4 | Liftoff |
| +60.9 | TV•(CES+CM) Sep |
| +90.9 | CES•CM Sep |
| +96.2 | APEX Cover Sep |
| +98.2 | D-CHUTE Mortar Ign |
| +307.7 | D-CHUTE Release |
| +307.9 | Main Chute Deploy |
| +312.5 | LT-UHF BEACON ON |
| +584.4 | IMPACT SENSING |

## Gallery

* Gaganyaan development timeline
* Gaganyaan Test Vehicle for TV-D1 abort test
* Gaganyaan TV-D1 test article
* TV-D1 flight profile
* TV-D1 test article with aeroskirt housing gridfins
* TV-D1 integration
* Stacking of TV-D1
* TV-D1 on pad
* The Gaganyaan capsule, along with the escape booster on the launchpad
* TV-D1 launch slow-mo
* TV-D1 onboard video
* Gaganyaan TV-D1 capsule successfully secured on deck of INS Shakti (A57)