BENGALURU: Weather permitting, Isro will attempt to achieve another milestone in the development of reusable launch vehicle (RLV) technology this month, may be as early as next week in Karnataka’s Challakere, while “issues” with chopper (Chinook) is delaying the integrated air-drop test (IADT) of simulated Gaganyaan crew modules at the spaceport in Sriharikota.
Isro, which had completed the second landing experiment of the RLV — the RLV-LEX-02 — on March 22, is gearing up for the third landing experiment (RLV-LEX-03), which will build upon RLV-LEX-02 aimed at improving the vehicle’s performance, guidance, and landing capabilities.
“…We are just waiting. The helicopter is there but the weather is bad. It (weather) is expected to improve by the 14th and if that happens we can conduct the experiment next week. This will be the last landing experiment and next, we’ll attempt the orbital re-entry,” S Unnikrishnan Nair, director, Vikram Sarabhai Space Centre (VSSC), which has developed the RLV, told TOI.
Compared to the previous LEX, Nair said, RLV-LEX3 will be more challenging as the “intentional cross-range error of around 500m will be tested, compared to around 150m during LEX-02. “The velocity azimuth with respect to the runway centre has been adjusted to 2°, deviating from the previous mission’s 0° alignment,” he said.
The mission will have another advancement: Implementation of an advanced guidance algorithm that can simultaneously correct errors in both the longitudinal and lateral planes. This decoupled algorithm, an improvement over LEX-02’s approach, will be utilised to enhance the vehicle’s precision and control.
Also, to ensure a softer landing and reduce touchdown loads, the main landing gear (MLG) sink rate has been reduced to less than 1m/second, compared to the 1.5m/second limit during LEX-02. Additionally, a smoke marker system has been introduced to trace the descent trajectory, providing visual data for analysis and future improvements.
Isro will also evaluate the performance of its real-time kinematics (RTK) system in a high-speed environment. This system is crucial for future landing missions, as it can enhance the robustness of the hybrid navigation system, ensuring accurate and reliable guidance.
Gaganyaan Test
Around 550km from Challakere, in Sriharikota, Isro’s plan of conducting the IADT of a simulated crew module to validate the parachute system for India’s first human spaceflight mission, Gaganyaan, has been put on hold a need to revisit “some aspects” of the helicopter selected to carry out the test, arose.
During the test, the crew module, weighing around 3 tonne, will be dropped from the Chinook helicopter at an altitude of 3km, and a sequence of parachute deployments will occur before splashdown and recovery. The proposed IADT is part of several such tests to be conducted as part of Gaganyaan’s preparations.
TOI had reported in May that pre-mission trials had begun for this. “…During the pre-mission trials for the first IADT in Sriharikota, it was noticed that the helicopter may have ‘some issues’ that needed to be addressed. That is progressing now,” a source said.
The Indian Air Force (IAF), whose Chinook aircraft Isro is using for the mission, is conducting an investigation “to understand what needs to be done”, the source said, adding that Isro was waiting for IAF to get back with its findings before moving ahead.
Isro plans to conduct seven IADTs as per initial plans, with the final number depending on the test results. Alongside these tests, it is also preparing for at least one uncrewed mission and the second test vehicle mission to test various abort conditions as part of the Gaganyaan programme this year.
Isro, which had completed the second landing experiment of the RLV — the RLV-LEX-02 — on March 22, is gearing up for the third landing experiment (RLV-LEX-03), which will build upon RLV-LEX-02 aimed at improving the vehicle’s performance, guidance, and landing capabilities.
“…We are just waiting. The helicopter is there but the weather is bad. It (weather) is expected to improve by the 14th and if that happens we can conduct the experiment next week. This will be the last landing experiment and next, we’ll attempt the orbital re-entry,” S Unnikrishnan Nair, director, Vikram Sarabhai Space Centre (VSSC), which has developed the RLV, told TOI.
Compared to the previous LEX, Nair said, RLV-LEX3 will be more challenging as the “intentional cross-range error of around 500m will be tested, compared to around 150m during LEX-02. “The velocity azimuth with respect to the runway centre has been adjusted to 2°, deviating from the previous mission’s 0° alignment,” he said.
The mission will have another advancement: Implementation of an advanced guidance algorithm that can simultaneously correct errors in both the longitudinal and lateral planes. This decoupled algorithm, an improvement over LEX-02’s approach, will be utilised to enhance the vehicle’s precision and control.
Also, to ensure a softer landing and reduce touchdown loads, the main landing gear (MLG) sink rate has been reduced to less than 1m/second, compared to the 1.5m/second limit during LEX-02. Additionally, a smoke marker system has been introduced to trace the descent trajectory, providing visual data for analysis and future improvements.
Isro will also evaluate the performance of its real-time kinematics (RTK) system in a high-speed environment. This system is crucial for future landing missions, as it can enhance the robustness of the hybrid navigation system, ensuring accurate and reliable guidance.
Gaganyaan Test
Around 550km from Challakere, in Sriharikota, Isro’s plan of conducting the IADT of a simulated crew module to validate the parachute system for India’s first human spaceflight mission, Gaganyaan, has been put on hold a need to revisit “some aspects” of the helicopter selected to carry out the test, arose.
During the test, the crew module, weighing around 3 tonne, will be dropped from the Chinook helicopter at an altitude of 3km, and a sequence of parachute deployments will occur before splashdown and recovery. The proposed IADT is part of several such tests to be conducted as part of Gaganyaan’s preparations.
TOI had reported in May that pre-mission trials had begun for this. “…During the pre-mission trials for the first IADT in Sriharikota, it was noticed that the helicopter may have ‘some issues’ that needed to be addressed. That is progressing now,” a source said.
The Indian Air Force (IAF), whose Chinook aircraft Isro is using for the mission, is conducting an investigation “to understand what needs to be done”, the source said, adding that Isro was waiting for IAF to get back with its findings before moving ahead.
Isro plans to conduct seven IADTs as per initial plans, with the final number depending on the test results. Alongside these tests, it is also preparing for at least one uncrewed mission and the second test vehicle mission to test various abort conditions as part of the Gaganyaan programme this year.
