0.99 Reliability & indigenous on-board intel

Astronaut training

Chandrayaan-2 to be launched by mid-April 2019: ISRO chairman K Sivan

BENGALURU: Isro is aiming for a manned mission to space in December 2021. This will be preceded by two unmanned missions, slated for December 2020 and July 2021.Isro got a shot in its arm with the approval of Rs 10,000 crore budget for the human space mission recently. On Friday, agency chief K Sivan reiterated that the final decision on how many people will go to space has not been taken yet."The endeavour is to build capacity for three people and seven days. But since this is the first mission, we will have to see how many we can send. Those decisions will be made later," Sivan K said.Sivan said that the agency has formed a new Human Spaceflight Centre (HSC) which will be headed by senior scientist Unnikrishnan Nair. While Nair will be the director of the HSC, R Hutton, had been named the project director or Gaganyaan But there is a long march before executing the ambitious mission, with crucial human-rating of the systems including the rocket yet to be achieved.Human-rating is the certification that says the system is capable of safely transporting humans, and has adequate technology that efficiently protects the crew (humans) in the event of any failure.Chairman Sivan K said told TOI: “There is a lot of work in front of us, and we are working relentlessly. We could not have gone ahead without the money being approved as the mission needs a lot of new testing and development that is cost-sensitive.”Most amount of the money— at least 50% of the Rs 10,000 crore— will go into human-rating of various systems, while a new launch pad that can accommodate entry of astronauts will also take up some money.“We have to build three sets of rockets, crew and service module for the project, and all of them have to be human-rated. Although I don’t have the exact break-up of the figures at this moment, building three GSLV-MK III launch vehicles and the other modules and conducting various human-rating tests will definitely use about 50% of the budget,” Sivan said.Each set will be used for three missions: Two unmanned missions planned in December 2020 and June-July 2021, and the actual mission which Isro hopes to achieve by December 2021 or early 2022.S Somnath, director, Vikram Sarabhai Space Centre (VSSC) had in a recent presentation at the Institute of Aerospace Medicine (IAM)— which will select and train the astronauts for the human space mission— elaborated on some of the pending working that Sivan mentioned.“We have already held 5-10 meetings on the roadmap for human-rating the launch vehicle. Since GSLV has been in active development since 2002-04, we had the vision that this could one day be used for the human mission which has been on the drawing table for long. So, it will be slightly more easy to make this rocket human-rated,” Somnath said.Explaining that all systems for a space launch are designed with redundancies, he said that a human-rated mission will need a much higher degree of redundancy.“The reliability targeted for human-rated launch vehicle is 0.99, which means statistically only 1 out of 100 can be unreliable. And, for the crew escape system, which is very crucial, we are targeting greater than 0.998, which means we want almost 100 reliability,” Somnath told TOI on Friday.The crew escape system will boast of a recently included geometry, while work on parachute enlargement— as models tested so far have been scaled down version and the actual system will be bigger— and new architecture will be ready soon.“Rockets are autonomous after launch so we cannot tolerate any failure. So a series of tests to make it reliable, including tests of the various regimes of flight, stability et al will be done first,” Somnath said.The crew escape system is very crucial, and for that a lot of advancement has happened with the crucial tests, including the pad abort test (PAT) done on July 5 this year.“Even if one system fails we will bring the crew back. And for this, the most important thing is failure detection and on-board intelligence that tells the system to abort. New algorithms to go into the system will be ready soon. And an indigenous computer and microprocessor will also be used. Control systems, avionics and sensors are ready,” Somnath said.Isro chief K Sivan Sivan said that astronaut selection and training, which will including establishment of some new facilities, will also take up considerable amount of the budget.“There is still some things that need to be done, and this aspect of the project will use up about 10% of the budget cleared for the human mission,” Sivan said.Isro is at present in the process of creating a framework for astronaut selection and the IAM is yet to get the specifics. The IAM already has some systems in place for astronaut selection and training as reported by TOI. And India is looking at a pool of 30 astronauts from whom the final crew will be selected.