The initial plan was for Indian astronauts to wear the IVA suits made in India. Recent mission planning, however, indicates that Russian spacesuits are preferred due to programmatic needs and an extra degree of assurance for crew safety. “Considering the programmatic requirements and to doubly ensure crew safety, it is planned to induct Russian space suits for the (Gaganyaan) mission,” an official document sent to the English daily said.

The year, 2024, is marked as ‘The Year of Gaganyaan' by the Indian Space Research Organisation (ISRO) chief, S Somanath, who emphasised its importance in the Gaganyaan timeline. At this critical juncture in the planning and implementation of this historic space project, ISRO has scheduled important mission-related tests and demonstrations throughout the entire year.

ISRO Gaganyaan Mission: is aimed at showcasing India's capacity to carry out its first human spaceflight programme, ISRO is gearing up for a momentous milestone with its ambitious Gaganyaan mission. The goal of the project is to safely return a crew of three people to Earth by putting them into orbit at a height of 400 kilometres for a three-day stay.

To ensure the program's complete success, ISRO is concentrating on several tests and programmes in advance of the historic human mission. The production of a human-rated launch vehicle that can safely carry the crew into space is at the forefront of this endeavour, alongside the development of crucial technologies. Furthermore, construction is being done on a life-support system that will give the crew an Earth-like environment while they are in space. Developing a thorough framework for crew management that addresses such issues as training, recuperation and rehabilitation is another priority for ISRO.

ISRO is scheduled to carry out some critical preparatory missions before the Gaganyaan spacecraft is launched. Test Vehicle (TV) flights, the Pad Abort Test (PAT) and the Integrated Air Drop Test (IADT) are a few of these. These test flights are essential for evaluating and improving different systems to ensure they are safe and reliable in the harsh environment of space. Before commencing manned operations, unmanned missions will also be carried out to confirm and improve the overall robustness of the systems.

A major step forward for India in the field of human space exploration, ISRO's devotion to meticulous testing, technological developments and exhaustive preparations demonstrates its dedication towards accomplishing a successful Gaganyaan mission.

Since it was first introduced in 1973, the Sokol space suit—also referred to as the Sokol IVA suit, or just the Sokol (Russian: Coкол, lit. ‘Falcon')—has been a mainstay of Soviet and Russian space missions. As of 2023, it is still in use and was intended to be worn by every Soyuz spaceship occupant. To differentiate it from suits meant for extravehicular activities or spacewalks, the Sokol is officially categorized as a rescue suit.

The Sokol is essential in the event of an unexpected spaceship depressurization, unlike suits made for spacewalks. The major goal of the Sokol is to guarantee the wearer's survival in an emergency by preserving a life-sustaining environment within the suit, despite certain parallels with NASA's Advanced Crew Escape Suit (ACES), which is worn during space shuttle launches and landings.

The Sokol has been a life-support system under dire circumstances for a long time, which is proof of its dependability and efficiency in space exploration. Although it is not designed for extravehicular operations, its vital function in protecting astronauts in space highlights how important it is to the general safety of human missions.

Specifications and variants: Since its debut in 1973 with the Sokol-K model, the Sokol space suit—a crucial part of intra-vehicular activity (IVA)—has experienced multiple revisions. With a weight of 10 kg (22 lb) and an operating pressure of 400 hPa (5.8 psi), the Sokol-K was first deployed on the Soyuz-12 mission in September 1973. It was used on missions from Soyuz-12 to Soyuz-40 (1981) and was based on the Sokol aircraft full-pressure suit.

The Sokol-KR version was created particularly for the Almaz program and the TKS spacecraft. Different from its counterparts, the Sokol-KR had a regenerative life support system, although the TKS spacecraft never flew with a crew.

The Sokol-KM and KV were intermediate variants that included several advancements after the Sokol-K. These included a liquid-cooled undergarment, a two-piece design secured with zip fasteners, and improvements to the joint fabric for better mobility. Yet, the Sokol-KM and KV were not successful in reaching orbit.

An upgraded model, the Sokol-KV, weighed 12 kg (26 lb) and operated at 400 hPa (5.8 psi). It had the liquid-cooled undergarment, which effectively removed body heat to maximize wearer comfort, although it was never used on a space mission.

Sokol& Mercury comparisons: In emergency scenarios, astronaut survivability is given priority by both the American Mercury spacesuit and the Russian Sokol spacesuit. However, the Sokol is unique given that it is dependable across many years of space flights, acting as a life-support system in the event of unplanned spaceship depressurizations. As a result of its proven ability to maintain a life-sustaining environment within the suit—an essential feature for guaranteeing astronaut safety in space exploration emergencies—the Sokol has a strong reputation as a rescue suit.

The Sokol spacesuit shows improvements in design, while the Mercury spacesuit was revolutionary for its day, with features including an aluminium-coated nylon shell for thermal regulation. To effectively control body temperature and improve wearer comfort, the Sokol-KV version, for instance, incorporates a liquid-cooled undergarment. The Russian spacesuit temperature regulation is a vital component for astronaut well-being on long-duration missions and this invention demonstrates their dedication to enhancing this aspect of their suits.

Better joint fabric, a two-piece design fastened with zips and a liquid-cooled undergarment are all features of the Sokol spacesuit's progression, which enhances wearer comfort and mobility. Examples of these models are the Sokol-KM and KV. On the other hand, astronauts in the Mercury spacesuit expressed dissatisfaction with the suit due to inadequate temperature regulation and restricted head mobility. To improve mission efficiency as a whole, Sokol's design improvements are centred on resolving astronaut concerns.

With its simple zips and airtight seals, the Sokol spacesuit's design places strong emphasis on user-friendliness. Making sure every member of the Soyuz crew gets a custom-fit suit is important for the suit's operation during launch and re-entry. On the contrary, despite being functional in its intended capacity, the Mercury spacesuit needed to be specially tailored for every astronaut and, during missions, astronauts complained of pain. The Sokol's applicability in real-world space mission conditions is attributed to its user-friendly features and attention to fit customization.

In case of an emergency, both suits have pressure relief valves, with the Sokol enabling modifications to various pressure levels. As the Mercury spacesuit was made to withstand a maximum pressure of 3.7 pounds per square inch, it was not flexible enough to change pressure levels in an emergency. By allowing astronauts to balance movement and survival, the Sokol's capacity to modify pressure settings—albeit under dire circumstances—illustrates a more flexible approach to managing emergencies.

The upcoming missions of ISRO apart from the Gaganyaan mission are: NASA-ISRO SAR (NISAR) Mission: Jointly developed by NASA and ISRO, the NASA-ISRO SAR (NISAR) is intended to be a Low-Earth Orbit (LEO) observatory. NISAR's main goal is to map the whole planet every 12 days. By doing this, it provides reliable spatial and temporal data that can be used to track changes in the planet's ecosystems, ice mass, biomass of flora, sea levels, groundwater and natural hazards, such as landslides, tsunamis and earthquakes.

The Synthetic Aperture Radar (SAR) equipment operating in L and S bands is dual-band and is used by the observatory. High-resolution data across a broad swath is made possible by the novel Sweep SAR technology. With the use of repeat-pass InSAR techniques, NISAR seeks to serve both national interests and the scientific community worldwide in its study of surface deformations.

NASA's contribution entails delivering the L-Band SAR payload system, engineering payloads and key equipment, such as the Payload Data Subsystem, High-rate Science Downlink System, GPS receivers, and a Solid State Recorder. In the interim, ISRO provides the S-Band SAR payload and the two agencies work together on a sizeable shared unfillable reflector antenna.

The capacity for high-resolution, high-repeat-cycle data collection has been improved by this ground-breaking project, which is the first dual-frequency radar imaging mission in the L- and S-bands. Encompassing a broad spectrum of phenomena from plant changes to ice sheet collapse and natural disasters, NISAR focuses on three primary disciplines: ecosystems, deformation studies and cryosphere sciences.

A 12-m wide deployable mesh reflector designed by JPL is installed on a 9-m boom at the observatory. The Integrated Radar Instrument Structure (IRIS) contains the SAR payloads and associated electronics, while the spacecraft incorporates attitude and orbit control elements, power systems and thermal management.

Three phases make up the development of NISAR: SIT-2, which is for the independent development of SAR payloads and engineering systems; SIT-3, which is for integration and testing at JPL; and the ongoing SIT-4 phase, which is for performance evaluation of the observatory as a whole. The mission will be launched in the first quarter of 2024 from the Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota, utilizing the GSLV expendable launch vehicle provided by ISRO.

After launch, a 90-day commissioning phase will include an in-orbit checkout to get the observatory ready for science operations. The ultimate aim is to accomplish the Level-1 research goals and give the scientific community useful data. (IPA Service)