After a technical glitch almost aborted its Flight Test Vehicle Abort Mission (TV-D1) to carry out a test for the Crew Escape System to be used in the maiden Indian human space flight Gaganyaan, the Indian Space Research Organisation (ISRO) carried out a perfect execution of the mission Saturday. The launch of the mission that was scheduled for 8 am was delayed to 8.45 am due to weather factors and a snag in the ignition of the rocket at 8.45 am put the mission on hold. However, scientists were able to quickly identify and correct the anomaly and return to the launchpad at the Satish Dhawan Space Centre at Sriharikota for a launch at 10 am. What followed was a smooth launch of the new Test Vehicle – a rocket developed by ISRO to test various systems for its first human space mission Gaganyaan in a two-year time frame – and a perfect execution of the abort mission for the crew module leading to a crew escape system separating from the rocket at an altitude of approximately 17 km. The crew module made a successful splashdown in the Bay of Bengal around 10 km off the Sriharikota coast at the programmed velocity and in the nominal time of a little over nine minutes after the 10 am lift-off. The module was recovered by the Indian Navy using a dedicated vessel and diving team. "We have had full accomplishment of the TV-D1 mission. The purpose of this mission was to demonstrate the crew escape system through a test vehicle demonstration in which the vehicle has gone up to a Mach no (1.2 Mach) – which is the speed of sound – and initiated an abort condition for the Crew Escape System mission," ISRO chairman S Somanath said soon after. #WATCH | Sriharikota: ISRO launches test flight for Gaganyaan mission ISRO says "Mission going as planned" pic.twitter.com/2mWyLYAVCS — ANI (@ANI) October 21, 2023 "The Crew Escape System took the module away from the test vehicle and subsequently the operation of the separation of the Crew Module from the Crew Escape System occurred with parachutes opening and the Crew Module touched down in the sea. The required velocity has been very much accomplished. We have got confirmation of the data for all of this," he said. What caused initial delay Somanath also dwelled on the reasons for the launch going into hold mode in the final second of the countdown at 8.45 am after the initial weather-linked delays. "After going through the nominal lift-off process, there was a hold issued by the ground computer which is called the Automatic Launch Sequence (ALS) computer which detected a sort of non-confirmation for the engine to continue with the thrusting for further go. This happened due to an anomaly in the system. We could identify it very fast and correct it," the ISRO chairman explained. "To make the stage ready again it took some time to refill the gases. After this was done, we went through the proper Automatic Launch Sequence which checked every health component of the vehicle and finally the mission computer and the ground check-up computer authorised the launch for take-off,” Somanath said. This “released the rocket from the launch pad and subsequently the activities of the flight and the post-termination abort sequence also got executed perfectly." "I am very happy that our team could understand that in case of any anomaly how things can be rectified and come back as fast as possible," he said. "This is a big training for the entire team here to prepare for the Gaganyaan programme. I am very happy the launch could take place within the allocated launch window. We will come back with more analysis and data for this mission on recovery of the Crew Module. We are having visuals from the sea and the drone cameras," the ISRO chief added. Mission director S Shivakumar said the three experiments in the mission had all performed well. "The test vehicle, the crew module, the crew escape system, everything has been demonstrated in the first attempt except for the hitch which was not a problem at all. All the systems performed well," he said. ‘Major milestone in Gaganyaan mission’ Gaganyaan programme director and executive for crew module realisation R Hutton said it was a major milestone for the mission. "As far as the Gaganyaan programme is concerned, this is the first major milestone and it is going to be a great motivator for us in the Gaganyaan mission across ISRO centres," he said. "In the Gaganyaan mission, the most important aspect is the safety of the crew. This safety has been demonstrated in this mission where we have simulated an abort and the crew escape system carried the crew module away like a bird is taking away its chicken to a safe place," Hutton said. "Though the Gaganyaan vehicle is robust and very reliable, we cannot leave anything to chance and after all if any malfunction happens there has to be a system in the launch vehicle which is called the crew escape which will take the crew module away to safety," he said. "The test vehicle is a novel vehicle derived from the liquid propulsion strap on a stage of the GSLV but it is entirely of a new architecture." Earlier in the morning, the countdown for the launch had entered the final second for lift-off when the rocket seemed to stall on the launch pad – after the countdown from 10 had reached down to 1. The launch was immediately announced as being put on hold by the mission control. Somanath was heard telling the scientists that the launch "will not be possible today". "Engine ignition did not take place. The Automated Launch Sequence started as planned but did not complete. The launch will be scheduled after correcting the anomalies," he soon announced publicly. Low-cost, exclusive Test Vehicle The abort mission was carried out by ISRO on a newly developed, low-cost rocket called the Test Vehicle which is to be used for testing ISRO systems before carrying out a full-fledged unmanned test flight into space and back for the crew module on ISRO's human-rated LVM3 rocket (an upgraded version of its heavy lift GSLV Mk III rocket) in 2024. The Flight Test Vehicle Abort Mission 1 (TV-D1) is the first of two abort missions to test crew safety mechanisms for the Gaganyaan mission planned by ISRO. The new test vehicle was built exclusively to test systems instead of waiting for PSLV and GSLV launches. The new rocket is basically expected to help the space agency avoid the large costs it would incur otherwise in testing the crew module for the human space flight programme which has a budget of around Rs 9,000 crore. "The Test Vehicle is a single-stage liquid rocket developed for this abort mission. The payloads consist of the Crew Module (CM) and Crew Escape Systems (CES) with their fast-acting solid motors, along with CM fairing (CMF) and Interface Adapters," ISRO said. Crew safety the chief priority With crew safety as the central objective of the Gaganyaan mission, ISRO had convinced the Union government that the 2022 deadline (set by Prime Minister Narendra Modi on August 15, 2018) would have to be relaxed in order to ensure a safe and successful mission. The crew module is at the heart of a human space mission and it needs to be safe to carry astronauts under very high heat and pressure conditions into space. It requires a reliable escape mechanism in the event of an emergency. The objectives of the mission were "flight demonstration and evaluation of Test Vehicle sub systems, flight demonstration and evaluation of Crew Escape System including various separation systems, and Crew Module characteristics and deceleration systems demonstration at higher altitude and its recovery". "This Test Vehicle mission with this CM is a significant milestone for the overall Gaganyaan programme as a near-complete system is integrated for a flight test. The success of this test flight will set the stage for the remaining qualification tests and unmanned missions, leading to the first Gaganyaan mission with Indian astronauts," ISRO said. In the TV-D1 mission, the Crew Module was empty but in an actual human mission, the capsule would be where the astronauts are "contained in a pressurized earth-like atmospheric condition". For the TV-D1 mission, it had an unpressurised version of the crew module. "This unpressurised CM version has to have an overall size and mass of actual Gaganyaan CM. It houses all the systems for the deceleration and recovery. With its complete set of parachutes, recovery aids, actuation systems and pyros," ISRO said. The module used in the flight on October 21 has been used to "capture the flight data for evaluation of the performance of various systems," the agency added.
