ISRO said on Saturday that its meteorological satellite, INSAT-3DS, is scheduled to be launched using the GSLV F14 rocket from the Satish Dhawan Space Centre (SDSC) in Sriharikota (SHAR).
The primary objectives of the INSAT-3DS Satellite include maintaining uninterrupted services provided by current satellites and improving the performance and functions of the INSAT system, observing land and sea areas for predicting weather conditions, and transmitting emergency signals to aid search and rescue operations.
INSAT-3: Bridging Space, Communication, and Meteorology
The INSAT-3 series, part of India’s expansive INSAT program, comprises six distinct types of geostationary satellites, with a seventh slated for launch in February 2024. These satellites, launched between 2000 and 2004, have played a crucial role in revolutionising India’s communication, television broadcasting, and weather forecasting capabilities. ISRO manages the series and includes notable satellites like INSAT-3B, 3C, 3A, 3E, and others. Specifically, INSAT-3A, INSAT-3D, and INSAT-3D Prime are equipped with advanced meteorological instruments, significantly enhancing weather monitoring and analysis in the region. Each satellite in the series has contributed uniquely to the growth and development of national and regional infrastructure in communications and meteorology.
The satellites in the INSAT-3 series were typically positioned in a geostationary orbit above the equator, primarily at the longitude of 83 degrees East. This strategic positioning allows them to cover the Indian region effectively, providing consistent communication, broadcasting, and meteorological services. Some satellites in the series were also placed at alternate longitudes, like 93.5 degrees East or 74 degrees East, for specific operational requirements or as replacements.
The INSAT-3 series is operated by the Indian Space Research Organisation (ISRO) in collaboration with the Indian Meteorological Department (IMD) for meteorological services and the Department of Telecommunications for communication services. The satellites are monitored and controlled from the Master Control Facility (MCF) located in Hassan and Bhopal, India. This collaboration and the sophisticated equipment of the facilities ensure efficient operation and utilisation of the satellites for various national needs.
INSAT-3 Series: Six Space Innovations
1. INSAT-3B, the inaugural satellite of the INSAT-3 series, was launched on March 22, 2000, by an Ariane-5G launch vehicle. It took off from the Guiana Space Centre in Kourou, French Guiana. This satellite enhanced India’s telecommunications, television broadcasting, and internet services. INSAT-3B has completed its operational life and is no longer in service.
2. INSAT-3C, the second satellite in the INSAT-3 series, is an Indian communication satellite launched on January 24, 2002. An Ariane-5G launch vehicle from the Guiana Space Centre in Kourou sent this satellite into orbit. Designed to improve India’s telecommunications and broadcasting infrastructure, INSAT-3C was equipped with C-band and extended C-band transponders. Having completed its operational lifespan, INSAT-3C is no longer in service.
3. INSAT-3A, the third satellite in the INSAT-3 series, is an Indian communication and meteorological satellite launched on April 10, 2003. It was deployed into orbit by an Ariane-5G launch vehicle from the Guiana Space Centre in Kourou. Designed to support telecommunications, television broadcasting, and meteorological services, INSAT-3A was equipped with C-band, extended C-band, and Ku-band transponders, along with meteorological instruments. INSAT-3A has completed its operational life and is no longer active.
4. INSAT-3E, the fourth satellite in the INSAT-3 series, was an Indian communication satellite launched on September 28, 2003. It reached orbit aboard an Ariane-5G launch vehicle from the Guiana Space Centre in Kourou. Specifically designed for communication services, INSAT-3E carried C-band and extended C-band transponders. It significantly enhanced India’s capacity for TV broadcasting, telecommunications, and satellite-based internet services. However, INSAT-3E ceased operations prematurely in April 2014 and is no longer in service.
5. INSAT-3D, the fifth satellite in the INSAT-3 series, was launched on July 26, 2013. It was sent into space aboard an Ariane 5 rocket from the Guiana Space Centre in Kourou, French Guiana. As a state-of-the-art meteorological satellite, INSAT-3D is equipped with advanced weather observation and atmospheric analysis instruments, significantly enhancing India’s capabilities in weather forecasting.INSAT-3D is still operational and actively contributing to meteorological monitoring and forecasting. It is likely to remain functional until the end of 2024.
6. INSAT-3DR (3D Repeat) is the sixth satellite in the INSAT-3 series. It was launched on September 8, 2016, aboard a GSLV Mk II rocket from the Satish Dhawan Space Centre in Sriharikota, India. INSAT-3DR is an advanced meteorological satellite with modern instruments for enhanced weather monitoring, atmospheric analysis, and disaster warning. This satellite is crucial in improving India’s weather forecasting and emergency response capabilities. INSAT-3DR is still operational and actively contributing to India’s meteorological services. It is likely to remain functional until the end of 2026.
The design life of the satellites in the INSAT-3 series is typically around 10 to 12 years. However, the actual operational lifespan varies based on individual satellite performance, technical issues, and other factors in the space environment. Some satellites have been functioning beyond their expected design life, while others might have gone for early retirement for various reasons.
The 7th Satellite
INSAT 3DS ( Indian National Satellite- 3D second Repeat) is the 7th satellite of the INSAT-3 series satellite.
ISRO declared on Saturday that its meteorological satellite, INSAT-3DS, is scheduled to be launched using the GSLV F14 rocket from the Satish Dhawan Space Centre (SDSC) in Sriharikota (SHAR).
The satellite was assembled, integrated, and tested at the U R Rao Satellite Centre in Bengaluru.
The INSAT-3DS satellite project, funded by users and overseen by the Ministry of Earth Science (MoES), is built on ISRO’s I-2k bus platform and weighs 2275 kg at launch. Indian enterprises have played a significant role in its development. INSAT-3DS is a dedicated weather satellite created to continue the work of the current INSAT-3D and 3DR satellites in orbit while greatly improving the performance of the INSAT system.
ISRO is preparing to launch the INSAT-3DS satellite, likely in the second week of February, using the GSLV-F14 rocket. This will mark ISRO’s second launch in 2024, following the year’s first mission with XpoSat on January 1, 2024. Initially expected to be launched in January, the INSAT-3DS mission faced delays for certain reasons and is now rescheduled for a February launch.
ISRO states that the satellite is designed to improve weather observations and track land and ocean conditions for forecasting weather and alerting about disasters. It’s equipped with four advanced payloads, which include a 6-channel Imager and a 19-channel Sounder for meteorology, plus communication systems like the Data Relay Transponder (DRT) and the Satellite Aided Search and Rescue (SAS&R) transponder.
INSAT 3D’S 4 payloads for weather forecasting
i. Data Relay Transponder (DRT): The satellite’s DRT instrument helps predict the weather. It does this by gathering weather, water, and ocean data from Automatic Data Collection Stations or platforms (ADCP) placed in various locations like oceans and Automatic weather stations (AWS) using its transponders
A transponder is a device that receives signals and automatically transmits a response. It is used in communication and satellite technology.
ii. Satellite-Aided Search and Rescue (SAS&R): The satellite includes a special transponder for Search and Rescue (SAS&R) that helps relay emergency signals from beacon transmitters to search and rescue services, covering the entire globe.
Beacon transmitters send signals to indicate location, often used in emergencies to help search and rescue teams find people in distress. Beacon transmitters are crucial in emergencies, used on ships, aeroplanes, and by outdoor adventurers. They signal distress, aiding rescuers in locating individuals in challenging environments.
iii. 6-Channel Imager (IMAGER): The satellite creates versatile images and figures out wind patterns by observing clouds and moisture in the air. It can capture details as small as 4.0 km in infrared, 1.0 km in visible or shortwave infrared (VIS /SWIR) channels, and 8.0 km in areas with water vapour.
Imagine the satellite like a super powerful camera in the sky. It can take different types of pictures. For heat-related images (infrared), it can see details up to 4 kilometres wide. For normal light or slightly beyond what our eyes can see (visible/shortwave infrared), it can see details as small as 1 kilometre wide. And for areas with lots of moisture in the air, it can see details that are 8 kilometres wide.
iv. 19-channel Sounder (SOUNDER): The satellite measures temperature and humidity using 19 channels. One of these channels can see in visible light, just like our eyes. It can pick up details from as far as 10 kilometres away, helping to understand weather conditions.
“Sounding” in meteorology refers to measuring and analysing various atmospheric parameters, such as temperature, wind speed and humidity at different altitudes. This is typically done using instruments on weather balloons, satellites, or radar to create a vertical atmosphere profile, which is crucial for weather forecasting and studying climate patterns.
Definitions
I-2K: Trusted Satellite Framework
The term “reliable I-2k bus platform” refers to a specific model or design of a satellite’s core structure developed by ISRO (Indian Space Research Organisation). In simpler terms, think of a satellite as a bus (vehicle) in space. The “I-2k bus platform” is like a vehicle’s chassis or base frame, attached to various components and instruments.
“I-2k” stands for “Indian 2000 kg” class, indicating that this platform is designed to support satellites weighing up to 2000 kilograms. The term “reliable” highlights that this design has been tested and proven to work well in previous space missions. It’s like saying a car model is reliable because it has been used many times and has a good performance and safety track record.
In the context of the satellite funded by the Ministry of Earth Science (MoES), using the I-2k bus platform means the satellite is built on a dependable and well-tested base, ensuring it can carry out its mission effectively in space.
Geostationary or Geosynchronous Orbit (GEO)
In a Geostationary Orbit (GEO), the distance from the satellite to the Earth’s surface remains relatively constant. However, at the highest and lowest points of the orbit, there can be slight variations in the distance due to the elliptical shape of the orbit. Typically, the distance at the highest point (apogee) of the GEO orbit is around 42,164 kilometres (26,199 miles), while the distance at the lowest point (perigee) is approximately 35,786 kilometres (22,236 miles).
GSLV F14 Rocket
GSLV F14 is a rocket that belongs to the GSLV MK II (Geosynchronous Satellite Launch Vehicle Mark II) family, developed by the Indian Space Research Organisation (ISRO). GSLV rockets are designed to launch satellites into geostationary transfer orbits, which are orbits around the Earth that have a period of one day. GSLV F14 is the 14th flight of the GSLV and is expected to launch in February 2024. It will transport the INSAT-3DS satellite, which serves dedicated weather forecasting purposes.
GSLV Mk II, developed by India, is designed to place communication satellites into a geo transfer orbit using a cryogenic upper stage. Initially, it used cryogenic stages provided by Russia, but later, India developed its cryogenic technology, first used in January 2014, starting with GSLV D5. This fourth-generation launch vehicle has three stages, including four liquid strap-on boosters. The locally developed Cryogenic Upper Stage (CUS) is a key feature of the GSLV Mk II. Since January 2014, this launch vehicle has completed six consecutive missions.
GSLV Mark II Family
The vehicle’s height is approximately 51.73 meters when equipped with the Ogive PLF. It comprises three stages and has a lift-off mass of 420 tonnes. The vehicle had its first flight on April 18, 2001, and a subsequent flight with the indigenous cryo stage on January 5, 2014.
Ogive PLF refers to the Ogive Payload Fairing. The Ogive PLF is a protective cover or casing shaped like an ogive, a rounded, pointed shape used to reduce aerodynamic drag and improve the vehicle’s flight performance. It is used to protect the payload (such as satellites or other instruments) during the launch and ascent phase of the vehicle’s flight.
i. The payload capacity of GSLV to Geosynchronous Transfer Orbit (GTO) is 2,250 kg. GSLV primarily launches communications satellites from the INSAT class, designed to operate from Geostationary orbits. To achieve this, GSLV places these satellites in Geosynchronous Transfer Orbits during the launch.
ii. The GSLV can carry payloads weighing up to 6,000 kg to Low Earth Orbit (LEO). This expands the range of payloads that can be launched, allowing for transporting multiple smaller satellites and larger, heavier ones.
The Three Stages
i.The GSLV’s first stage, GS1, borrows its design from the PSLV’s PS1. It features a 138-tonne solid rocket motor boosted by four additional liquid-fueled engines. The main engine, named S139, uses HTPB as its fuel. It can produce a maximum thrust of 4800 kN and has a burn time of about 100 seconds.
HTPB, or Hydroxyl-terminated polybutadiene, is a solid rocket fuel resembling rubber. It’s used in rocket motors for its stability and energy, providing efficient propulsion.
ii. The second stage of GSLV, known as GS2, is powered by a single Vikas engine. This stage is derived from the PS2 stage of PSLV, where the Vikas engine has already demonstrated its reliability. The Vikas engine used in the GS2 stage operates on a combination of UH25 fuel and N2O4 oxidiser. It provides a maximum nominal thrust of 846 kN and has a burn time of 150 seconds.
UH25 [( 75% UDMH and 25% hydrazine hydrate.) is a type of rocket fuel often called unsymmetrical dimethylhydrazine (UDMH). N2O4 refers to nitrogen tetroxide, an oxidiser commonly used in rocket engines. In combination, UH25 and N2O4 create a propellant mixture commonly used in liquid rocket engines like the Vikas engine.
iii. The third stage of GSLV, known as CUS (Cryogenic Upper Stage), features the CE-7.5 cryogenic engine. This engine, developed by the Liquid Propulsion Systems Centre as part of the Cryogenic Upper Stage Project (CUSP), operates on a combination of liquid oxygen (LOX) and liquid hydrogen (LH2) fuels. The CE-7.5 engine utilises a staged combustion operating cycle. It provides a maximum nominal thrust of 75 kN and has a burn time of 814 seconds.
