Bharat Rakshak

Isro on Sunday said that the Chandrayaan-3 lander successfully underwent EMI/EMC (Electro - Magnetic Interference/ Electro-Magnetic Compatibility) test between January 31 and February 2.

The test, it said: "Is conducted for satellite missions to ensure the functionality of the satellite subsystems in the space environment and their compatibility with the expected electromagnetic levels. This test is a major milestone in the realisation of the satellites."

Reiterating that the Chandrayaan-3 mission has three major modules: the Propulsion module, Lander module, and Rover, Isro said, the mission's complexity calls for establishing radio-frequency (RF) communication links between the modules.

"During the Chandrayaan-3 lander EMI/EC test, launcher compatibility, antenna polarization of all RF systems, standalone auto compatibility tests for orbital and powered descent mission phases, and lander & rover compatibility tests for post landing mission phase were ensured. The performance of the systems was satisfactory," Isro said.

Aside from this, the PSU has a busy year ahead with multiple commercial launch missions for both domestic and international customers lined up beginning March 2023, while it already launched two satellites — US’ Janus-1 and domestic Azadisat-2 — onboard Isro’s Small Satellite Launch Vehicle’s (SSLV) second demonstration mission (SSLV-D2) on February 10.

The next big launch through NSIL will be the GSLV-Mk3 or LVM3 mission to put 36 satellites belonging to Bhartibacked OneWeb. According to OneWeb, the satellites, which arrived at the Isro spaceport on January 27, have already been integrated on the dispenser as of February 20. As per NSIL, the launch is scheduled for March.

As reported earlier by TOI, the mission is part of the OneWeb-NSIL contract which has already put 36 satellites of the UK firm in orbit in LVM3’s maiden commercial mission on October 23, 2022.

“After the OneWeb mission, we have lined up three dedicated PSLV missions for international and domestic customers. The first one is expected in April, and then one in July and the third in August. Further, we have some missions in the pipeline for 2024 as well,” Radhakrishnan said.

Also, high on the success of SSLV-D2, NSIL is actively exploring ways and means to fund all future SSLVs after the third demonstration flight (SSLV-D3).

“Post SSLV-D3, NSIL wants to fund, acquire and market all SSLVs to meet the demand for small satellite launches. We will work out modalities of industry partnership. There could be a different model compared to PSLV and this will be fully industry produced. We are also looking at commercialisation of the GSLV-Mk3, which has been declared operational as part of our larger mandate,” Radhakrishnan added.

BENGALURU: The Indian Space Research Organisation (Isro) has moved one step closer to conducting an abort test using the special test vehicle (TV) as part of Gaganyaan with the space agency having received the Simulated Crew Module (SCM) Structure Assembly.
This first indigenous simulated crew module is developed by VSSC and realised by Manjira Machine Builders, Hyderabad.
“This is an unpressurised crew module where the interfaces of major systems like parachute systems and pyros are simulated. This module will be used for various missions like test vehicle missions where the crew escape system will be validated along with various crew module subsystems,” Isro said.
Isro added that the shape and outside mould line of the SCM is also simulated as per the crewed mission configuration. For the crewed mission, the crew module is a pressurised capsule and accommodates the astronauts during the Gaganyaan mission.
“This (the SCM delivered to Isro) will be flying as part of the first test vehicle mission. The test vehicle is already at SHAR (spaceport) and activities are being carried out,” S Unnikrishnan Nair, director, VSSC, which has developed the test vehicle, told STOI.
While Nair did not specify a timeline for the said mission given the complexities involved, multiple Isro officials said the agency is targeting it for the first half of this year. “Timelines cannot be sacrosanct in missions like this. This is the first time the country is attempting something like this and there are a lot of systems that are new,” one of them said.
The first abort test using the special test vehicle (TV) as part of Gaganyaan will see the simulated crew module separate from the TV at a height of around 11km (from sea level), attain an altitude of around 15km before falling back to back in the Bay of Bengal.
The test — TV technology demonstrator-1 (TV-TD1) mission — which is tentatively planned for the first half of this year, will be the first of several such tests Isro plans to conduct before the first uncrewed mission under Gaganyaan.
As per Isro plans, the vehicle will be taken to around 11km approximately and then from there, the crew module will go up to about 15-16km and then come down. Isro will demonstrate the coming down, descent phase, parachute deployment and recovery.
Another scientist explained that at the altitude of about 11km — the final mission profile will be made public at a later stage — the crew module will separate from the vehicle, escape from the trajectory of the vehicle, and then drop back.
During the mission, the ground team at Sriharikota will do the tracking. Once separated/ejected from the TV, the module will have a free fall — essentially demonstrating the crew escape system in an in-flight abort scenario.
This means navigation and guidance, control systems and parachutes will be demonstrated. A success in this will give Isro the confidence to expedite a lot of other processes.

BENGALURU: Isro is gearing up for a challenging experiment of controlled re-entry of a decommissioned low Earth orbiting satellite — Megha-Tropiques-1 (MT1) — on March 7. MT1 was launched on October 12, 2011, as a joint satellite venture of Isro and the French space agency, CNES, for tropical weather and climate studies.
As per the space agency, an uninhabited area in the Pacific Ocean between 5°S to 14°S latitude and 119°W to 100°W longitude has been identified as the targeted re-entry zone for MT1. And, since August 2022, 18 orbit manoeuvres have been performed to progressively lower the satellite’s orbit.
The final two de-boost burns followed by the ground impact are expected to take place between 4:30pm and 7:30pm on March 7 and Isro said aero-thermal simulations have show no large fragments of the satellites are likely to survive the aerothermal heating during the re-entry.
“Although the mission life originally was up to three years, the satellite continued to provide valuable data services for more than a decade supporting regional and global climate models till 2021,” Isro said.
The UN inter-agency space debris co-ordination committee (IADC) space debris mitigation guidelines recommend de-orbiting a low Earth orbit (LEO) object at its end-of-life, preferably through controlled re-entry to a safe impact zone, or by bringing it to an orbit where the orbital lifetime is less than 25 years. It is also recommended to carry out “passivation” of on-board energy sources to minimise the risk of any post-mission accidental break-up.
“The orbital lifetime of MT1, weighing about 1,000kg, would have been more than 100 years in its 20 deg inclined operational orbit of 867 km altitude. About 125kg on-board fuel remained unutilised at its end-of-mission that could pose risks for accidental break-up. This left-over fuel was estimated to be sufficient to achieve a fully controlled atmospheric re-entry to impact an uninhabited location in the Pacific Ocean,” Isro said.
It added that controlled re-entries involve de-orbiting to very low altitudes to ensure impact occurs within a targeted safe zone and that usually, large satellites/rocket bodies which are likely to survive aero-thermal fragmentation upon re-entry are made to undergo controlled re-entry to limit ground casualty risk.
“However, all such satellites are specifically designed to undergo controlled re-entry at end-of-life. MT1 was not designed for EOL operations through controlled re-entry which made the entire exercise extremely challenging. Furthermore, the on-board constraints of the aged satellite, where several systems had lost redundancy and showed degraded performance, and maintaining subsystems under harsher environmental conditions at much lower than originally designed orbital altitude added to the operational complexities,” Isro said.
Innovative workarounds were implemented by the operations team based on the study, deliberations, and exchanges among the mission, operations, flight dynamics, aerodynamics, propulsion, controls, navigation, thermal, and other sub-system design teams across the ISRO centres, who worked in synergy to surmount these challenges.
Stating that 18 orbit manoeuvres were performed to progressively lower the orbit, Isro said: “In between the de-orbiting, aero-braking studies at different solar panel orientations were also carried out to gain better insights into the physical process of atmospheric drag affecting the orbital decay of the satellite.”
The final de-boost strategy has been designed after taking into consideration several constraints, including visibility of the re-entry trace over ground stations, ground impact within the targeted zone, and allowable operating conditions of subsystems, especially the maximum deliverable thrust and the maximum firing duration of the thrusters.

Mar 06, 2023

ISRO conducted the Rail Track Rocket Sled deployment tests of the Gaganyaan Pilot and Apex Cover Separation (ACS) parachutes in cluster configurations at the Terminal Ballistics Research Laboratory (TBRL), Chandigarh, on March 1 and 3, 2023.

The first test simulated the clustered deployment of two pilot parachutes. One parachute was subjected to a minimum angle with respect to flow conditions and the second parachute was subjected to a maximum angle with respect to flow. These pilot parachutes are used in the Gaganyaan mission to extract and deploy the main parachutes independently.

The second test simulated the clustered deployment of two ACS parachutes under maximum dynamic pressure conditions. The test also simulated clustered deployment at a 90-degree angle of attack conditions for the crew module. The ACS parachutes are used in the Gaganyaan mission for the separation of the apex cover mounted on the Crew Module. Both pilot and ACS parachutes were deployed using a pyrotechnic mortar device.

The Gaganyaan parachute system development has been a joint effort by VSSC, Thiruvananthapuram and Aerial Delivery Research and Development Establishment (ADRDE), Agra.

Isro successfully completed the controlled re-entry for the decommissioned Megha-Tropiques-1 (MT-1) satellite on Tuesday.

“The final two de-boost burns were executed at 4.32pm and 6.22pm, respectively by firing four 11 Newton thrusters on-board the satellite for about 20 minutes each. The final perigee was estimated to be less than 80km indicating that the satellite would enter the denser layers of the Earth’s atmosphere and subsequently undergo structural disintegration. The re-entry aero-thermal flux analysis confirmed that there would be no surviving large debris fragments,” Isro said.

Isro progressively lowered the satellite’s perigee (nearest point to Earth) through a series of 20 manoeuvres, spending about 120kg fuel since August 2022. Multiple manoeuvres including the final de-boost strategy were designed after taking into consideration several constraints, including visibility of the re-entry trace over ground stations, ground impact within the targeted zone, and allowable operating conditions of subsystems, especially the maximum deliverable thrust and the maximum firing duration constraint on thrusters.

“All manoeuvre plans were screened to ensure that there would be no post manoeuvre close approaches with other space objects, especially with the crewed space stations like International Space Stations and the Chinese Space Station,” Isro said.

The latest telemetry has confirmed that the satellite re-entered the Earth’s atmosphere and would have disintegrated over the Pacific Ocean, the final impact region estimated is in deep Pacific Ocean within the expected latitude & longitude boundaries.

The entire sequence of events was carried out from the Mission Operations Complex in ISRO Telemetry, Tracking and Command Network (Istrac) in Bengaluru.

In recent years, Isro has taken up proactive measures to improve the compliance level with the internationally accepted guidelines on space debris mitigation. Efforts are underway to build indigenous capabilities for tracking and monitoring of space objects to safeguard Indian space assets, Isro said.

“The Isro System for Safe and Sustainable Space Operations Management (IS4OM) has been established to spearhead such activities. The controlled re-entry exercise bears yet another testimony to India’s continued efforts towards ensuring the long-term sustainability of outer space activities,” it added.

Multiple Manoeuvres including the final de-boost strategy were designed after taking into consideration several constraints, including visibility of the re-entry trace over ground stations, ground impact within the targeted zone, and allowable operating conditions of subsystems, especially the maximum deliverable thrust and the maximum firing duration constraint on thrusters. All manoeuvre plans were screened to ensure that there would be no post manoeuvre close approaches with other space objects, especially with the crewed space stations like International Space Stations and the Chinese Space Station. From the latest telemetry, it is confirmed that the satellite has re-entered the Earth's atmosphere and would have disintegrated over the Pacific Ocean, the final impact region estimated is in the deep Pacific Ocean within the expected latitude & longitude boundaries. The entire sequence of events was carried out from the Mission Operations Complex in ISTRAC.

The US Air Force C-17 aircraft landed in Bengaluru on Wednesday and handed over NASA-ISRO Synthetic Aperture Radar (NISAR) NISAR to the Indian space agency which marks a milestone in the US-India ties in space collaboration.

"Touchdown in Bengaluru! @ISRO receives NISAR (@NASA-ISRO Synthetic Aperture Radar) on a @USAirforce C-17 from@NASAJPL in California, setting the stage for final integration of the Earth observation satellite, a true symbol of #USIndia civil space collaboration," tweeted US Consulate General Chennai.

NISAR, an Earth-observation satellite, is being jointly developed by the National Aeronautics and Space Administration (NASA) and the Indian Space Research Organisation (ISRO).

NISAR was envisioned by NASA and ISRO eight years ago in 2014 as a powerful demonstration of the capability of radar as a science tool and help us study Earth's dynamic land and ice surfaces in greater detail than ever before.

It is expected to be launched in January 2024 from Satish Dhawan Space Centre into a near-polar orbit.The satellite will operate for a minimum of three years. It is a Low Earth Orbit (LEO) observatory. NISAR will map the entire globe in 12 days.

NISAR will be the first radar of its kind in space to systematically map Earth, using two different radar frequencies (L-band and S-band) to measure changes in our planet's surface less than a centimeter across.

NISAR will provide a wealth of data and information about the Earth's surface changes, natural hazards, and ecosystem disturbances, helping to advance our understanding of Earth system processes and climate change.

The mission will provide critical information to help manage natural disasters such as earthquakes, tsunamis, and volcanic eruptions, enabling faster response times and better risk assessments.

NISAR data will be used to improve agriculture management and food security by providing information about crop growth, soil moisture, and land-use changes.

The mission will provide data for infrastructure monitoring and management, such as monitoring of oil spills, urbanization, and deforestation.

NISAR will help to monitor and understand the impacts of climate change on the Earth's land surface, including melting glaciers, sea-level rise, and changes in carbon storage.

Tirupati: The Indian Space Research Organization (Isro) is gearing up for launch of LVM3 (Launch Vehicle Mark-3)-M3/OneWeb India-2 mission from the Satish Dhawan Space Centre in Sriharikota on Sunday.

This is the second mission for the private entity Network Access Associates Ltd, UK, a part of the OneWeb Group) under a commercial agreement with Isro's commercial arm - M/s. NewSpace India Ltd (NSIL). The agreement is to launch 72 satellites to Low-Earth Orbits.

While the first batch of 36 satellites were successfully launched by the Isro on October 23, 2022, the second and final batch of OneWeb's 36 more satellites under the LVM3-M3/OneWeb India-2 mission will be launched from the SDSC-SHAR at 9 am on Sunday.

Isro's NSIL released the LVM3-M3 OneWeb India-2 mission brochure on Thursday. It said the integration-related activities were under way at the second launchpad at SDSC-SHAR. In this mission, the LVM3 would place 36 OneWeb Gen-1 satellites totalling about 5,805 kg into a 450 km circular orbit with an inclination of 87.4 degrees.

In yet another milestone, Chandrayaan-3 spacecraft successfully completed the essential tests that validated its capability to withstand the harsh vibration and acoustic environment that the spacecraft would face during its launch. These tests were conducted during the first week of March 2023 at the test facilities located at the UR Rao Satellite Centre in Bengaluru. These tests are an essential part of the qualification & acceptance process for any spacecraft. These tests were particularly challenging, considering the fact that the Chandrayaan-3 spacecraft is a composite of three modules viz. Propulsion Module, Lander Module and the Rover module. The vibration and acoustic tests carried out on the integrated spacecraft has provided sufficient confidence on the structural integrity and survivability in the launch environment.

Pratyush wrote:Yet another textbook launch.

Congratulations to the entire ISRO team.

Mar 24, 2023

Today, ISRO received the Crew Module structure simulated assembly for the Integrated Air-Drop Test (IADT)meant for validating the sequence and performance of parachute systems in the Gaganyaan mission. The module was designed by Human Space Flight Centre (HSFC), ISRO and the hardware has been realized by Shri Venkateswara Aerospace Pvt. Ltd., Hyderabad. Shri Somanath S, Chairman, ISRO/ Secretary, DoS, and senior officials of ISRO graced the occasion.

This un-pressurized single wall Crew Module structure simulates the shapeand size of the actual Gaganyaan crew module. Its structure accommodates major subsystems like parachute system, pyros, avionics, and buoyance augmentation system for IADT. The IADT will be performed, at SDSC-SHAR, using an Indian Air Force helicopter by taking the Crew module to an altitude of 3.6 to 4km to validate the deceleration system (parachute & Pyro's) performance.

sanman wrote:Reusable Launch Vehicle Landing Experiment (RLV-LEX) successfully demonstrates autonomous landing

https://www.isro.gov.in/RLVTD.html
Hypersonic aero thermodynamic characterisation of wing body
Evaluation of autonomous Navigation, Guidance and Control (NGC) schemes
Integrated flight management
Thermal Protection System Evaluatio

Neela wrote:
Towards the end of the video , as the aircraft came to stop, there were balance issues after two distinct brake events c.