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RISAT

RISAT (Radar Imaging Satellite) is a series of satellites developed by the Indian Space Research Organisation (ISRO), featuring () payloads that enable high-resolution imaging regardless of weather conditions or daylight. The program addresses applications in , , soil and land use assessment, , and disaster management by providing continuous monitoring capabilities superior to optical satellites. Launched starting with in 2009 using an imported X-band from , the series marked India's entry into operational imaging from space, enhancing and environmental surveillance. , deployed in 2012 via PSLV-C19 as ISRO's first indigenous C-band satellite weighing 1,858 kg, introduced advanced modes like for sub-meter resolution and for estimation. Subsequent missions, including RISAT-2B (2019), RISAT-2BR1 (2019), and (2022)—a continuation in the series with X-band —have expanded the constellation for near-real-time in and resource mapping. The RISAT satellites operate in , typically around 500-800 km altitude, with mission lives of 5-10 years, supporting India's self-reliance in microwave technology amid challenges like complexity and for smaller payloads. Achievements include validated high-resolution imaging, as demonstrated by precise measurements of structures like the , and integration into operational services for cyclone tracking and flood delineation. No major mission failures have been reported in the core series, underscoring ISRO's reliability in deployment despite reliance on foreign components in early models.

Program Overview

Objectives and Rationale

The RISAT (Radar Imaging Satellite) program seeks to deliver continuous, all-weather, day-and-night microwave remote sensing data via synthetic aperture radar (SAR) payloads, overcoming the cloud and darkness limitations of optical satellites. Core objectives encompass applications in agriculture for crop monitoring and yield estimation, forestry for deforestation detection, soil moisture and geology assessments, ocean feature tracking, and natural hazard evaluation including floods, cyclones, and landslides. These capabilities enable precise measurements of land surface changes and support disaster management response. The program's rationale is rooted in India's strategic imperative for self-reliant , particularly amid vulnerabilities exposed by the , where delays in accessing foreign underscored risks of external dependence. RISAT satellites thus prioritize rapid, autonomous imaging for border surveillance, infiltration deterrence, and crisis monitoring, transitioning from foreign-sourced X-band in early missions like to indigenous C-band systems in and subsequent variants. This fosters technological independence while enhancing operational resilience against geopolitical data-sharing constraints. By integrating with ISRO's broader framework, RISAT addresses gaps in real-time environmental and resource data, aiding policy formulation in developmental sectors without compromising on verifiable, high-resolution intelligence needs.

Core Technical Specifications

The RISAT series employs () payloads for all-weather, day-and-night , with satellites operating in () sun-synchronous or mid-inclination configurations at altitudes of 536–576 km. , the inaugural indigenous model, features a C-band at 5.35 GHz, enabling multi-polarization imaging (single, dual, quad, and hybrid circular) across modes including high-resolution (HRS: <2 m , 10 km swath), fine-resolution stripmap (FRS: 2–4 m, 25 km swath), medium-resolution scansar (MRS: 25 m × 8 m, 115 km swath), and coarse-resolution scansar (CRS: 50 m × 8 m, 223 km swath). The satellite maintains a sun-synchronous dawn-dusk at 536 km altitude and 97.55° inclination, with a launch of 1858 , 2200 power generation, and a designed mission life of 5 years. Subsequent models like and the RISAT-2B series utilize X-band operating around 9.6 GHz for enhanced in strategic applications. , with a of 300 kg, supports stripmap (3 m ), scansar (8–20 m), (<1 m), and (1.8 m) modes in a 548 km, 41° inclination . The RISAT-2B variants, indigenously developed, achieve very high resolutions such as 0.5 m × 0.3 m in modes, with around 615–628 kg and at 576 km altitude and 37° inclination. These satellites feature deployable active antennas and agile pointing for flexible , supporting data rates up to 640 Mbps via X-band downlink.
Satellite VariantRadar Band & FrequencyKey Resolutions (m)Swath Range (km)Orbit Altitude (km) / Inclination (°)Launch Mass (kg)
RISAT-1C-band, 5.35 GHz1–5010–223536 / 97.551858
RISAT-2X-band, 9.65 GHz<1–20Varies by mode548 / 41300
RISAT-2B seriesX-band, ~9.6 GHz0.3–310–50576 / 37615–628
All variants incorporate 3-axis stabilization, reaction wheels for attitude control, and high-capacity onboard storage to handle SAR's data-intensive operations, prioritizing applications in , monitoring, and .

Historical Development

Inception Post-2008 Security Needs

The 26 November 2008 terrorist attacks in , perpetrated by Pakistan-based militants who infiltrated via sea, exposed significant gaps in 's coastal and real-time intelligence gathering, as the operation evaded detection despite prior warnings and involved coordinated strikes across multiple urban sites, resulting in 166 deaths. These events highlighted the limitations of optical satellites, which are ineffective in cloud cover, fog, or nighttime conditions prevalent along 's borders and maritime approaches, prompting a strategic pivot toward (SAR) technology for persistent, all-weather monitoring. In the aftermath, India's defense establishment, including the and security agencies, prioritized rapid deployment of imaging capabilities to address border security vulnerabilities, particularly against infiltration from neighboring hostile territories. This urgency stemmed from the attacks' demonstration of asymmetric threats exploiting weather-obscured routes, leading to accelerated of foreign technology as an interim measure while lagged. Specifically, delays in ISRO's C-band for the planned satellite necessitated hastening the integration and launch of , an X-band payload sourced from , to provide immediate enhancements in detecting small targets like vessels or personnel movements. Launched on 20 April 2009 aboard PSLV-C12 from Sriharikota, RISAT-2 operated at a 550 km sun-synchronous orbit, enabling round-the-clock vigilance over India's 7,500 km coastline and land borders with a resolution sufficient for security applications, such as tracking potential infiltrators in adverse conditions. This deployment marked the inception of operational radar imaging under the RISAT program, directly tied to post-2008 imperatives for proactive threat detection, and later supported actions like the 2016 cross-border strikes by furnishing actionable imagery of terror infrastructure. The satellite's 300 kg mass and three-year design life underscored its role as a bridge to fully indigenous systems, reflecting a causal link between the Mumbai failures and India's investment in space-based ISR to mitigate similar risks.

Transition to Indigenous Capabilities

The urgency following the prompted to prioritize rapid deployment of radar imaging capabilities, leading to the procurement of with an Israeli-supplied X-band () from , launched on April 20, 2009, at a cost of approximately USD 200 million. This foreign dependency highlighted the need for , as accelerated parallel indigenous development of a C-band to avoid future reliance on external vendors for sensitive national security applications. RISAT-1, launched on April 26, 2012, via PSLV-C19, incorporated ISRO's first fully indigenous orbital system operating at 5.35 GHz in C-band, enabling multi-mode imaging resolutions from 1 to 3 meters in spotlight, stripmap, and scanSAR modes. The payload's core innovations included indigenously designed solid-state RF transmitter systems and transmit-receive (T/R) modules developed by the (SAC), building on prior experience with an airborne system operationalized in the mid-1990s. Control application-specific integrated circuits () for these modules were also domestically engineered, though initial fabrication occurred in foreign foundries due to limited indigenous semiconductor infrastructure at the time. This transition catalyzed broader indigenization, expanding India's space-grade SAR subsystem manufacturing base through collaborations with domestic industries and enhancing operational independence for all-weather, day-night surveillance. Subsequent missions, such as RISAT-1A in 2022, further refined these capabilities with improved power efficiency and , solidifying self-reliance in imaging technology.

Individual Satellite Missions

RISAT-2 (2009)

RISAT-2, a 300 kg radar imaging , was launched on April 20, 2009, at 01:15 UTC aboard the PSLV-C12 rocket from the in , . The mission deployed the satellite into a at approximately 550 km altitude with a 41-degree inclination, enabling all-weather, day-and-night imaging capabilities through its primary payload, an X-band () instrument. This SAR system provided high-resolution imagery with spatial resolutions up to 1 meter, supporting applications in disaster management and surveillance. The satellite's design incorporated an Israeli-derived IMS-2 radar system procured by from , marking an early step in India's program before full development. enhanced India's infrastructure by delivering data for monitoring terrain, , and coastal zones, independent of or lighting conditions, which optical satellites cannot achieve. Specific operational modes included high-resolution for detailed target analysis and wider swath scanning for broader area coverage, contributing to real-time responses in flood mapping and forest fire detection. In contexts, supported border surveillance and anti-infiltration efforts by providing persistent imaging over strategically sensitive regions, filling gaps left by weather-dependent assets. The mission operated successfully for over 13 years beyond its planned lifespan, demonstrating robust orbital maneuvering and attitude control systems managed by ISRO's ground stations. It concluded with an uncontrolled atmospheric re-entry on , , with the predicted in the near , ensuring no risk to populated areas due to prior predictions. This extended service validated the reliability of imported technology integration into ISRO's platform while paving the way for subsequent indigenous RISAT variants.

RISAT-1 (2012)

RISAT-1, India's first indigenously developed radar imaging satellite, was launched on April 26, 2012, at 00:17 UTC from the in using the (PSLV-C19). The satellite, weighing 1851 kg, carried a C-band () payload operating at 5.35 GHz, enabling all-weather, day-and-night capabilities. Designed with a nominal mission life of five years, it was placed in a sun-synchronous dawn-dusk orbit at 536 km altitude with an inclination of 97.55° and local time on ascending node options of 0600 and 1800 hours. The SAR payload supported multiple imaging modes, including fine resolution (3 m), medium resolution (up to 50 m), and coarse resolution modes like ScanSAR and Stripmap, with swath widths ranging from 107 to 659 km. It featured hybrid polarimetry for enhanced target discrimination and a data downlink rate of 640 Mbps via X-band, supported by an 1800 W power system and 70 Ah nickel-hydrogen battery. Three-axis stabilized with S-band telemetry, tracking, and command, RISAT-1 prioritized applications in , , assessment, flood monitoring, and coastal . During its operational phase, which extended until March 2017, RISAT-1 provided critical data for flood inundation mapping, rice acreage estimation, and vegetation analysis, demonstrating the viability of indigenous technology for national and . The mission marked a shift from reliance on foreign SAR systems, as seen in the earlier , to self-developed capabilities, though it faced eventual decommissioning due to payload degradation, paving the way for successors like RISAT-1A.

RISAT-2B and Variants (2019)

RISAT-2B, a imaging , was launched on 22 May at 00:00 UTC aboard the (PSLV-C46) from the in , . Weighing 615 kg at launch with a designed mission life of five years, it operates in a at approximately 555 km altitude and 37° inclination, enabling frequent passes over the . The satellite carries an X-band () payload featuring a 3.6-meter deployable Radial Rib Antenna (RRA), which was successfully unfurled in orbit on the same day at 2:20 pm IST, marking a key technological demonstration for lightweight, high-performance structures. This all-weather, day-and-night imaging capability supports applications in management, monitoring, and assessment by penetrating clouds and providing high-resolution imagery. As the first in a planned series of RISAT-2B-class satellites, RISAT-2B addressed the need for enhanced radar imaging capacity following the aging of earlier models like , with intending to deploy multiple units for improved revisit times and constellation redundancy. The mission achieved precise orbital insertion, with separation occurring 15 minutes and 29 seconds after liftoff, confirming the PSLV's reliability for such payloads. A variant, RISAT-2BR1, followed later in 2019 as an upgraded iteration with refined radar processing for specialized modes. Launched on 11 2019 at 09:55 UTC via PSLV-C48 from the same , it had a launch of 628 kg and was placed into a 576 circular orbit at 37° inclination. Equipped with an X-band payload similar to RISAT-2B but optimized for finer agricultural and data, RISAT-2BR1 enhances through timely all-weather , complementing the initial satellite's capabilities in building India's indigenous fleet. Both satellites underscore 's shift toward serial production of compact systems, reducing reliance on foreign technology while maintaining operational secrecy on exact resolution metrics for reasons.

RISAT-1A and EOS Series (2022 Onward)

RISAT-1A, also designated , represents the primary radar imaging satellite in the EOS series launched from 2022 onward, serving as a direct successor to to maintain continuity in all-weather capabilities. Launched on 14 February 2022 at 00:29 UTC aboard the PSLV-C52 rocket from the , the 1750 kg satellite was placed into a sun-synchronous at approximately 529 km altitude with a 97.3° inclination. The mission included two co-passenger satellites, INS-2TD and INSPIREsat-1, demonstrating 's multi-payload launch efficiency. Equipped with an indigenous C-band () payload, RISAT-1A operates in multiple imaging modes, including spotlight, stripmap, and scanSAR, offering spatial resolutions from 1 meter in high-resolution mode to 50 meters in wide-swath mode, with swath widths ranging from 10 km to 225 km. This configuration enables day-and-night, all-weather imaging essential for applications such as crop monitoring, forestry assessment, estimation, and flood mapping, with enhanced polarimetric capabilities over its predecessor for improved target discrimination. The satellite's 5-year mission life supports operational data continuity for civilian and strategic users, generating data at rates up to 640 Mbps via X-band downlink. In the broader EOS series, which encompasses diverse earth observation platforms, radar imaging efforts continued with EOS-09 (formerly RISAT-1B), a near-identical repeat of EOS-04 designed for similar SAR-based remote sensing objectives. With a launch mass of 1696 kg and the same C-band SAR payload, EOS-09 aimed to bolster constellation redundancy and data frequency. However, its launch attempt on 18 May 2025 via PSLV-C61 failed during the third stage ignition, resulting in the satellite not achieving the targeted 529 km sun-synchronous orbit; the failure was attributed to a propulsion anomaly, marking ISRO's first PSLV mission shortfall in over a decade. No additional EOS radar satellites were launched between 2022 and October 2025, though the series underscores ISRO's emphasis on indigenous SAR technology for sustained national observation needs.

Operational Applications

Civil and Environmental Uses

RISAT satellites, equipped with (SAR) payloads, enable all-weather, day-and-night imaging that supports various civil applications by penetrating cloud cover and vegetation canopies to provide data on surface features. Primary civil uses include agricultural monitoring, where the satellites' C-band SAR facilitates crop inventory, growth stage assessment, and yield estimation through repeated temporal sampling optimized for monsoon-season observations. For instance, RISAT data has been applied to map rice crops and assess flood impacts in regions like , integrating SAR with optical data for district-level damage estimates. In , RISAT supports applications such as detection, forest fire mapping, and estimation by analyzing signatures from tree canopies and . assessment benefits from the radar's sensitivity to dielectric properties, aiding water resource management and drought prediction at resolutions suitable for field-scale analysis. Coastal and oceanographic uses extend to detection via slick signatures on sea surfaces and mapping in shallow waters, enhancing tracking. Disaster management represents a core civil application, with RISAT enabling rapid mapping through water-body delineation even under dense cloud cover prevalent during monsoons. Missions like (launched 2022) have demonstrated near-real-time extent estimation using multi-mode data, supporting national-level response coordination. Additionally, the series aids in monitoring landslides and cyclones by providing structural damage assessments and inundation patterns, contributing to mitigation planning in vulnerable areas. These capabilities derive from the satellites' high-resolution imaging (down to 1-3 meters in spotlight modes), which allows precise change detection over time.

National Security and Surveillance Roles

The RISAT series satellites, equipped with synthetic aperture radar (SAR) payloads, enable all-weather and day-night imaging, which is essential for applications where optical satellites are limited by cloud cover or darkness. These capabilities support persistent monitoring of India's borders, particularly along the with and the with , facilitating the detection of infiltrations and troop movements. Following the 2008 Mumbai terrorist attacks, which highlighted vulnerabilities in real-time intelligence gathering, expedited the deployment of in April 2009, incorporating an Israeli-supplied X-band for high-resolution border surveillance and anti-infiltration operations. Weighing 300 kg, was designed specifically to track suspicious activities and support counter-terrorism efforts, providing imagery with resolutions suitable for identifying vehicles and personnel. Subsequent indigenous missions, such as launched in April 2012 with a C-band , extended these roles by offering multi-mode imaging for , including spotlight modes for detailed target analysis. Later variants like RISAT-2B, launched in May 2019, introduced finer resolutions down to 0.5 meters in very high-resolution modes, enhancing for tactical operations and in sensitive areas. The 2022 launch of RISAT-1A and the May deployment of RISAT-1B (also referred to as EOS-09 in some contexts) further bolstered these functions with improved C-band , enabling the identification of minor ground changes indicative of terrorist preparations or violations, thus aiding swift responses. In broader defense contexts, RISAT data integrates with ground systems for real-time threat assessment, contributing to by monitoring coastal intrusions and supporting efforts, though primary emphasis remains on terrestrial border security amid ongoing regional tensions. These satellites reduce reliance on foreign , aligning with 's strategic push for self-reliant space-based amid export controls on dual-use technologies.

Achievements and Strategic Impact

Contributions to Self-Reliance

The RISAT program has significantly advanced India's indigenous capabilities in () technology, transitioning from reliance on foreign payloads to fully homegrown systems. RISAT-1, launched on April 26, 2012, featured ISRO's first domestically developed C-band , enabling all-weather, day-night imaging independent of optical satellites or external data providers. This milestone reduced dependence on imported technologies, previously demonstrated by the X-band in (2009), and established a foundation for sovereign microwave . Key subsystems, including high-power radar transmitter systems and circuits, were indigenously engineered by ISRO's (SAC) in , supporting operations and fostering expertise in gallium nitride-based amplifiers for enhanced efficiency. Similarly, control application-specific integrated circuits () for transmit/receive (T/R) modules in payloads were developed domestically, though initial fabrication occurred abroad due to limited local foundries at the time; these modules serve as building blocks for broader radar applications, promoting to Indian industries. The program's expansion, including RISAT-1A (launched May 2022) and variants like RISAT-1B, has scaled production of space-grade components, catalyzing private sector involvement and reducing import reliance for defense and civil imaging needs. This self-sufficiency ensures uninterrupted access to high-resolution data for , disaster monitoring, and resource assessment, insulating from geopolitical restrictions on foreign . Overall, RISAT has bolstered in space, with leveraging mission data to refine algorithms and hardware for future constellations.

Demonstrated Mission Successes

The RISAT series has demonstrated operational success through reliable launches, extended mission durations exceeding design life in key cases, and validated imaging applications in challenging conditions. , India's first indigenous C-band () satellite, launched on April 26, 2012, via PSLV-C19, operated for 4 years and 11 months, fulfilling its 5-year design life while enabling all-weather, day-and-night imaging across multiple modes including , stripmap, and scanSAR. Its polarimetric capabilities were demonstrated in April 2013, supporting hybrid polarimetry for enhanced target discrimination in and . of 13 beams in fine (FRS-1) mode and one in medium scanSAR (MRS) mode was achieved using corner reflectors by November 2014, ensuring data accuracy for estimation validated with root mean square errors of 6.2–8.5% in field tests in in August 2015. Specific imaging demonstrations underscored RISAT-1's utility in disaster management, including flood extent mapping in Indonesia in February 2015 and Malaysia in December 2014 using MRS mode data, which facilitated rapid assessment despite cloud cover. In agriculture, it supported crop area estimation, such as for Samba rice in Tamil Nadu in 2013, contributing to yield forecasting and resource allocation. Near real-time data delivery, achieved by November 2014 via ground stations like KSAT’s SvalSat, reduced processing times to under one hour, enhancing responsiveness for coastal monitoring and forestry applications. Subsequent missions built on these foundations. , launched July 20, 2009, via PSLV-C12, enhanced with X-band data for flood, , and management, demonstrating high-resolution surveillance in obscured conditions. , injected into a 556 km orbit on May 22, 2019, by PSLV-C46, successfully deployed its 3.6-meter radial rib antenna—developed indigenously in 13 months—enabling continuous for , , and disaster mitigation over its 5-year mission life. (EOS-04), launched February 14, 2022, via PSLV-C52, extended these successes with improved resolution for , flood mapping, and agricultural monitoring, operating in all-weather scenarios to support and environmental assessment. Variants like , launched December 11, 2019, further validated the series' reliability by providing data amid export restrictions on foreign tech.

Challenges and Criticisms

Technical and Developmental Delays

The development of RISAT-1's indigenous C-band encountered significant technical hurdles, including challenges in achieving the required for all-weather and reliable deployment mechanisms, which postponed the satellite's launch from initial targets in the late to , 2012. These issues stemmed from the complexity of integrating high-power radar electronics with precise , necessitating extensive ground testing and iterative design refinements to ensure operational stability in orbit. Subsequent efforts to advance self-reliant payloads for follow-on missions, such as (RISAT-1A), faced persistent teething problems with indigenous components, notably the failure of more than 20 transmit-receive () modules during ground tests, which delayed the PSLV-C52 integration and launch from planned 2021 timelines to February 2022. The TR module defects, linked to thermal and electrical reliability under simulated space conditions, underscored gaps in domestic fabrication processes for high-frequency arrays, requiring redesigns and requalification to mitigate risks of in-orbit failures. Broader developmental across the RISAT series arose from the transition to fully indigenous systems, including algorithms and payload integration, which demanded prolonged validation against international benchmarks amid limited access to foreign verification tools. External factors, such as the , further compounded these by disrupting testing schedules and supply chains for specialized materials, pushing multiple missions into 2022. Despite these setbacks, the facilitated incremental improvements in efficiency, though they highlighted the inherent risks of rapid indigenization without parallel redundancy in prototyping.

Geopolitical and Export Control Constraints

The development of India's Radar Imaging Satellite (RISAT) series has been shaped by international export control regimes, particularly those governing dual-use technologies under the (MTCR) and , which restrict transfers of () systems capable of high-resolution imaging for potential military applications. Prior to India's MTCR membership in June 2016, Western suppliers, including the and European entities, imposed stringent licensing requirements and frequent denials on advanced SAR components, citing proliferation risks and India's non-signatory status to the Nuclear Non-Proliferation Treaty. These constraints compelled the Indian Space Research Organisation () to pursue alternative partnerships and accelerate indigenous efforts, as foreign approvals were often delayed or withheld to prevent technology leakage to adversarial states. A pivotal example occurred with , launched on April 20, 2009, aboard a PSLV-C12 , which incorporated an Israeli-supplied X-band payload derived from the EL/M-2050 system, similar to that on Israel's TecSAR . This off-the-shelf acquisition was expedited in under five months following the 2008 Mumbai terrorist attacks, addressing urgent gaps in all-weather border surveillance amid delays in India's indigenous C-band for RISAT-1. Israel's willingness to provide the technology stemmed from shared strategic interests against common threats, bypassing U.S.-influenced restrictions that had limited options from American or European vendors, who viewed exports to as sensitive due to its program and regional tensions with and . These geopolitical hurdles extended beyond to broader program timelines, contributing to RISAT-1's launch postponement from a planned 2009 slot to April 26, 2012, as prioritized domestic radar development to mitigate dependency risks. Post-2016 MTCR accession and inclusion in the , export barriers eased somewhat, enabling limited U.S.-India collaborations in space but not fully resolving sensitivities around military-grade imaging tech. Consequently, later RISAT variants, such as RISAT-2B (launched May 22, 2019) and RISAT-1A (February 2022), emphasized indigenous advancements, reflecting a strategic pivot toward driven by persistent foreign supply uncertainties. This , while advancing technical autonomy, incurred higher costs and developmental delays, underscoring how export controls inadvertently bolstered 's resolve against external dependencies.

Future Prospects

Planned Missions and Upgrades

ISRO attempted to launch EOS-09, designated as RISAT-1B and intended as a direct follow-on to RISAT-1A with comparable C-band () payload for high-resolution all-weather imaging in applications such as , , soil moisture assessment, and monitoring. The 1,670 kg was slated for deployment into a 535 km via PSLV-C61 on May 18, 2025, from , but the mission failed after normal performance through the second stage, due to an anomaly in the third stage that prevented orbit insertion. To bolster India's SAR constellation, ISRO collaborated with on the NISAR mission, featuring dual-frequency (L-band and S-band) instruments capable of 5-10 meter resolution imaging over a 240 km swath, enabling detailed tracking of surface deformations, changes, and natural hazards independent of weather or daylight. Launched successfully on July 30, 2025, aboard GSLV-F16 from , NISAR represents a technological upgrade in interferometric precision and coverage compared to prior RISAT missions, with agreements enhancing ISRO's analytical capabilities for and . Subsequent RISAT-series missions are anticipated to prioritize indigenous payload refinements, including improved signal processing for finer resolution and polarimetric modes, as ISRO addresses gaps from the EOS-09 failure and integrates operational feedback from RISAT-1A to expand the fleet's redundancy and revisit frequency. As of October 2025, no firm launch timelines for RISAT-1B equivalents or advanced variants like potential RISAT-2A have been publicly detailed, reflecting ongoing evaluations of PSLV reliability and SAR subsystem autonomy.

Integration with Broader ISRO Ecosystems

The RISAT series forms a critical component of the Indian Space Research Organisation's () Earth observation constellation, which comprises over a dozen operational satellites as of 2023, enabling comprehensive all-weather imaging alongside optical missions such as Resourcesat and Cartosat. This integration enhances 's capacity for continuous monitoring in sectors like and disaster management, where RISAT's C-band (SAR) provides data penetration through clouds and darkness, complementing the daytime, clear-sky limitations of electro-optical sensors. For instance, RISAT data has been fused with multispectral imagery from other ISRO satellites to generate value-added products, such as crop condition assessments and maps, processed within unified geospatial workflows. RISAT satellites are launched using ISRO's (PSLV), exemplifying seamless coordination between the satellite development and launch vehicle programs; was deployed via PSLV-C19 on April 26, 2012, while subsequent variants like () utilized PSLV-XL configurations for precise orbital insertion into . Ground segment integration occurs primarily through the (NRSC) in , ISRO's dedicated facility for data reception, processing, and dissemination from the entire (IRS) series, including RISAT. NRSC's Shadnagar Earth station captures RISAT signals, applying specialized preprocessing algorithms to produce Level-1 and Level-2 products, which are archived in the Bhoonidhi portal for user access and integrated into national GIS platforms. This centralized architecture ensures interoperability, with RISAT data contributing to operational services like the high-resolution product launched in February 2024 using imagery. Further synergy exists with ISRO's Space Applications Centre (SAC) in Ahmedabad, which develops RISAT's indigenous SAR payloads and supports algorithm refinement for multi-mission data fusion, as seen in applications combining RISAT SAR with INSAT meteorological data for flood forecasting. These integrations bolster ISRO's self-reliant ecosystem, reducing dependence on foreign data sources and enabling real-time analytics through standardized interfaces across satellite, launch, and user segments.

References

  1. [1]
    RISAT-1 - ISRO
    Sep 15, 2023 · RISAT-1 is a state of the art Microwave Remote Sensing Satellite carrying a Synthetic Aperture Radar (SAR) Payload operating in C-band (5.35 GHz).
  2. [2]
    RISAT-2BR1 - ISRO
    Sep 15, 2023 · RISAT-2BR1 is a radar imaging earth observation satellite. The satellite will provide services in the field of Agriculture, Forestry and Disaster Management.
  3. [3]
    RISAT-2 - ISRO
    Sep 15, 2023 · RISAT-2 is a Radar Imaging Satellite with all weather capability to take images of the earth. This Satellite enhances ISRO's capability for Disaster Management ...
  4. [4]
    RISAT-2B - ISRO
    Sep 15, 2023 · RISAT-2B is a radar imaging earth observation satellite developed by ISRO. प्रमोचन भार / Launch Mass: 615 Kg मिशन कालावधि / Mission Life : 5 Years
  5. [5]
    PSLV-C48/RISAT-2BR1 - ISRO
    Sep 22, 2023 · RISAT-2BR1 is a radar imaging earth observation satellite weighing about 628 kg. The satellite will provide services in the field of Agriculture ...
  6. [6]
    [PDF] PSLV-C52/ EOS-04 - ISRO
    EOS-04 is a Radar Imaging Satellite designed to provide high quality images under all weather conditions for applications such as Agriculture, Forestry and ...
  7. [7]
    RISAT-1 (Radar Imaging Satellite-1) - eoPortal
    Jul 1, 2025 · RISAT-1 is the first indigenous satellite imaging mission of ISRO (Indian Space Research Organization) using an active radar sensor system, ...
  8. [8]
    India's RISAT-1 High Resolution SpotLight (HRS) - ISRO
    May 1, 2023 · The height of the tower is computed from the image as 105 m. It was found to match with the actual height. Howrah Bridge, Kolkata, (Date of Pass ...
  9. [9]
    RISAT-2 (Radar Imaging Satellite-2) - eoPortal
    Aug 29, 2025 · Hence, RISAT-2 was India's first satellite with a synthetic aperture radar (SAR), which possessed a 24-hour, all-weather monitoring capability.
  10. [10]
    RISAT 1, 1A, 1B (EOS 04, 09) - Gunter's Space Page
    Jun 1, 2025 · RISAT 1 (Radar Imaging Satellite 1) is the first satellite imaging mission of ISRO using an active C-band SAR (Synthetic Aperture Radar) imager.
  11. [11]
    How RISAT-1B strengthens India's eye in the sky and enhances ...
    May 9, 2025 · Launched after the 2008 Mumbai attacks, the series was designed to bolster border surveillance and deter infiltration. Satellites like RISAT- ...<|separator|>
  12. [12]
    [PDF] RADAR Imaging Satellite (RISAT) 1 - UNOOSA
    Feb 11, 2013 · 3-Axis Stabilized, 1851 kg mass. • 1800w power & 70AH Ni H Battery. • S-Band TTC & X-Band DH. • 640 Mbps Data Rate (320 Mbps RHCP,.
  13. [13]
    India's first 'spy' satellite that helped in planning surgical strikes ...
    Nov 5, 2022 · Due to a delay in the locally built C-band for the RISAT-1 satellite, the launch of RISAT-2 was hastened after the 26/11 terrorist attacks in ...
  14. [14]
    Radar Imaging Spacecraft RISAT - GlobalSecurity.org
    Aug 5, 2019 · This is to be utilized to address defense border security issues for India. This RISAT-2 and the new in development dedicated Military Naval ...
  15. [15]
    India successfully launches spy satellite RISAT -2 - NDTV
    Apr 20, 2009 · The all-weather satellite can keep a close vigil over India's borders and hostile neighbours.
  16. [16]
    An Indo-Israeli Handshake in Space | IPCS
    The successful launch of India's all weather , microwave imaging satellite RISAT-2, which ISRO(Indian Space Research Organisation) says was realized in ...
  17. [17]
    Indian PSLV launches RISAT-2BR1 military satellite
    Dec 10, 2019 · RISAT-2 was developed under a partnership between ISRO and Israel Aerospace Industries (IAI) and was based on the Israeli TecSAR radar-imaging ...
  18. [18]
    India launches its first indigenous Radar Imaging Satellite
    Apr 26, 2012 · The Indian Space Research Organisation (ISRO) has successfully launched the country's first indigenous Radar Imaging Satellite (RISAT-1) ...
  19. [19]
    High Power Radar Transmitter Systems And Circuits - ISRO
    SAC has indigenously designed and developed solid-state RF transmitter systems and TR modules for SAR payloads.
  20. [20]
    Near Real Time SAR Processors for ISRO's Multi-Mode RISAT-I and ...
    Indian Space Research Organisation's (ISRO) developed an indigenous C-band Airborne Synthetic Aperture Radar (ASAR) in mid-1990s and operationalised it in ...
  21. [21]
    Self-Reliance in control ASIC of T/R Modules for SAR Payloads - ISRO
    Chip was fabricated in a foreign foundry due to the lack of indigenous semiconductor foundry during the timeframe of development of RISAT-1. During the ...<|separator|>
  22. [22]
    NASA-ISRO Satellite Lifts Off to Track Earth's Changing Surfaces
    an L-band system and an S-band system. Each system ...
  23. [23]
    pslv-c12 / risat-2 - ISRO
    Sep 18, 2023 · PSLV is a four-stage launch vehicle employing both solid and liquid propulsion stages. PSLV is the trusted workhorse launch Vehicle of ISRO.
  24. [24]
    Atmospheric Re-entry of RISAT-2 - ISRO
    Nov 2, 2022 · The satellite has now made an uncontrolled re-entry into the Earth's atmosphere at the predicted impact point in Indian Ocean near Jakarta on 30th October 2022.
  25. [25]
    ISRO RISAT-2 ISRO Space Mission Mission: Objectives, Launch ...
    Following its launch on April 20, 2009 via PSLV-C12, the spacecraft was deployed into Low Earth Orbit, ~550 km altitude, 41° inclination. The mission ...
  26. [26]
    RISAT-2 - ISRO Satellite - SatNow
    It was launched on 20 April 2009 from SHAR Centre, Sriharikota, India. This mission was carried out in PSLV-C12 launch vehicle and has a mass of 300 Kg.
  27. [27]
    RISAT 2 - Gunter's Space Page
    Jun 1, 2025 · RISAT 2 (Radar Imaging Satellite 2) is a satellite imaging mission of ISRO using an active X-band SAR (Synthetic Aperture Radar) imager.Missing: specifications details
  28. [28]
    Satellite: RISAT-2 - WMO OSCAR
    Radar Imaging Satellite - 2 | 2nd flight unit of the RISAT programme, actually launched before RISAT-1. Main mission: reconnaissance and disaster management.
  29. [29]
    RISAT-2 - Drishti IAS
    Nov 5, 2022 · Risat-2, weighing about 300 kg was launched on April 20, 2009, by the PSLV-C12 launch vehicle. Significance: Risat-2 provided beneficial payload ...
  30. [30]
    [PDF] RISAT-1: Configuration and Performance Evaluation - URSI
    Major specifications of the SAR system are summarised in Table-3. RISAT-1 SAR has total 126 antenna beams. Each beam definition comprises of two transmit beams ...<|separator|>
  31. [31]
    RISAT-1: Configuration and performance evaluation - ResearchGate
    In April 2012 ISRO launched RISAT-1, i.e. the first satellite imaging mission independently developed by ISRO, which operated until March 2017 and collected SAR ...
  32. [32]
    PSLV-C46 Mission - ISRO
    Sep 17, 2025 · The satellite is intended to provide services to Agriculture, Forestry and Disaster Management domains.
  33. [33]
    Indian PSLV rocket launches RISAT-2B - NASASpaceFlight.com -
    May 21, 2019 · Equipped with X-band radar imagers, RISAT-2B will monitor the Earth day and night, in any weather conditions. Two or three RISAT-2B spacecraft ...
  34. [34]
    [PDF] PSLV-C46 RISAT2B launch kit.indd - ISRO
    RISAT-2B. 6. Glimpses. 7. 2. Page 3. Page 4. 4. Flight Events. Time after ... RISAT-2B Separation. 15 min 29.42 s. 558.902 7580.81. PSLV-C46 FLIGHT SEQUENCE.
  35. [35]
    [PDF] PSLV-C48/RISAT-2BR1 Mission 2 - ISRO
    (PSLV-C48), will launch RISAT-2BR1, the primary satellite along with. 9 customer satellites of Israel (1), Italy (1), Japan (1) and USA (6).
  36. [36]
    EOS-04 - ISRO
    May 1, 2023 · EOS-04 is a Radar Imaging Satellite designed to provide high quality images under all weather conditions for applications such as Agriculture, Forestry & ...
  37. [37]
    [PDF] EOS-04 - Bhoonidhi - NRSC
    Risat-2 series of satellites are launched to support X band SAR data to cater to strategic requirements. A series of satellites are dedicated to ocean ...
  38. [38]
    [PDF] PSLV-C61/EOS-09 MISSION - ISRO
    EOS-09 is a repeat satellite of EOS-04, designed with the mission objective to ensuring remote sensing data for the user community engaged in operational ...
  39. [39]
    PSLV launch of Indian radar imaging satellite fails - SpaceNews
    May 17, 2025 · The payload, the EOS-09 satellite, is identical to the EOS-04 satellite launched in 2022. The satellite weighed nearly 1,700 kilograms at launch ...
  40. [40]
    PSLV-C61 / EOS-09 Mission - ISRO
    May 17, 2025 · On 18 May 2025 at 05:59 AM IST, ISRO will launch EOS-09 aboard the PSLV-C61 from the First Launch Pad (FLP) at Satish Dhawan Space Centre, SHAR ...
  41. [41]
    Earth Observation Satellites - ISRO
    Dec 5, 2023 · RISAT-2BR1, Dec 11, 2019, 628 Kg, PSLV-C48/ RISAT-2BR1, LEO (Low Earth Orbit), Disaster Management System, Earth Observation. 37, Cartosat-3 ...EOS-07 · Cartosat-3 · Sslv-d2/eos-07 mission · EOS-06
  42. [42]
    [PDF] SYNTHETIC APERTURE RADAR PAYLOAD OF RADAR IMAGING ...
    Basic hardware specifications of the RISAT-SAR are presented in Table-1. The SAR consists of two broad segments namely (1) Deployable Active Antenna and (2) RF ...
  43. [43]
    [PDF] Use of Remote Sensing Technology in Crop Monitoring and ...
    Feb 17, 2025 · Odisha Rice-Flood Assessment. (Rice Map of Odisha from RISAT Data). (Flood Map of Odisha, upto 17th Oct., ISRO). An Estimate of District wise ...
  44. [44]
    [PDF] Signatures - Special Issue on RISAT - 1 - Space Applications Centre
    Figure-3: Specifications, Block Schematic & photographs of RISAT-1 SAR Frequency Generator ... like flatness, spectral purity, fine frequency resolution.
  45. [45]
    Effective utilization of RISAT-1A multi-mode satellite data for near ...
    Aug 4, 2025 · The present research focuses on using data from the newly launched EOS-04 to develop a methodology for automated, rapid estimation of flood ...
  46. [46]
    EOS-09 satellite set to be launched on May 18, will boost India's ...
    May 11, 2025 · The satellite will play a key role in boosting India's surveillance along its sensitive borders with arch-rivals Pakistan and China, and guarding vast ...
  47. [47]
    India's Military Space Program - GlobalSecurity.org
    Oct 17, 2023 · India began its unmanned RISAT ... Pushed by Indian immediate national security concerns that it not fall behind in intelligence surveillance ...
  48. [48]
    ISRO Launch: RISAT-1B to Enhance India's Border Surveillance
    May 12, 2025 · RISAT-1B can play a key role in anti-terrorist operations as it can more accurately pick up suspicious movements on the ground as terrorists try ...
  49. [49]
    Orbital Militarization and India's Maritime Security - CeSCube
    Oct 12, 2025 · The surveillance front has also been boosted with the deployment of new reconnaissance satellites such as the EMISAT and RISAT series. The ...
  50. [50]
    India's Space Priorities Are Shifting Toward National Security
    Sep 1, 2022 · Some of India's earliest military satellites, such as the RISAT series, were specifically meant to do this. Though initially developed in ...
  51. [51]
    [PDF] Major Activities of ISRO
    ... RISAT-2B, 2BR1, EOS-01are the some of the state-of-the-art missions ... Specifications of CUS Stage. Cryogenic Propulsion Development. LPSC, in 1995 ...
  52. [52]
    [PDF] foreword - ISRO
    Satellite (RISAT- 1). It is a building block for radars and finds its applications in weather radar,ground based radar etc. Each TR Module consists of a low ...
  53. [53]
    [PDF] Research Areas in Space - ISRO
    SAC has developed indigenous atomic clocks for India's navigation programme – ... SAR Images from RISAT-1 / RISAT-1A(EOS-04) / RISAT-1B (EOS-09) missions can ...
  54. [54]
    Hi-tech antenna of Risat-2B, developed in record 13 months by Isro ...
    May 23, 2019 · Successful deployment of the antenna in Risat-2B ... Weighing 615kg, Risat-2B, which replaced Risat-2, will have a mission life of five years.
  55. [55]
    Tango with Israel - Frontline - The Hindu
    May 22, 2009 · It now seems that all the problems with RISAT-1 have been successfully solved, and the indigenous radar imaging satellite, which has a high- ...
  56. [56]
    Teething troubles with indigenous tech cause for delay in 2 Sat ...
    Dec 1, 2021 · Teething troubles with multiple indigenous modules on one satellite and domestic mirror fabrication on the other are major causes for delay ...
  57. [57]
    Isro gears for first launch of 2022, RISAT-1A to liftoff in February
    Feb 1, 2022 · The final date for the launch is yet to be announced. Several missions led by Isro had been delayed in the last two years due to the coronavirus ...<|separator|>
  58. [58]
    Export Controls: Balancing the Tensions Between U.S. and Indian ...
    Jun 5, 2025 · First, while India's export controls are currently based on multilateral regimes, it may now seek to incorporate elements in its domestic export ...
  59. [59]
    Navigating Export Controls in U.S.-India Relations - ORF America
    Jul 12, 2025 · U.S. export controls are complex, with disaggregated processes, no single approval process, and concerns about India's relations with Russia ...<|control11|><|separator|>
  60. [60]
    India's Space Program: Challenges, Opportunities, and Strategic ...
    Feb 10, 2016 · While success in sending a satellite into orbit around Mars and a rover onto the moon has boosted the Indian space program's credentials, ...
  61. [61]
    Space: Why Risat 2 Came Before Risat 1 - StrategyPage
    May 3, 2012 · India already has a radar satellite in orbit: Risat 2. This one was bought from Israel and launched three years ago using a PSLV rocket.
  62. [62]
    US-India Strategic Cooperation in Space and its Implications for...
    This cooperation has been further strengthened by India's inclusion in pivotal export control frameworks, such as the MTCR, the Wassenaar Arrangement, and its ...
  63. [63]
    The transformation of India's space policy - ScienceDirect.com
    This article explores the transformation of India's space policy from a focus on space for development to the pursuit of security and prestige.
  64. [64]
    The Geostrategic Implications of India's Space Program
    Aug 6, 2025 · This article critically examines the geostrategic implications of India's space program. The article first reviews the history of India's ...
  65. [65]
    ISRO's EOS-09 (RISAT-1B) launch failure during 3rd stage - SatNews
    May 18, 2025 · Onboard was a single 1,600 kilogram plus radar imaging reconnaissance satellite, EOS-09 (RISAT-1B), into Sun-synchronous orbit.
  66. [66]
    5 Things to Know About Powerful New U.S.-India Satellite, NISAR
    Jul 21, 2025 · In 2012, ISRO began launching SAR missions starting with Radar Imaging Satellite (RISAT-1), followed by RISAT-1A in 2022, to support a wide ...
  67. [67]
    [PDF] Diverse Space Applications - ISRO
    Also active fire monitoring uses satellite data from the Moderate Resolution. Imaging Spectro radiometer (MODIS), which is a satellite-based sensor used for ...
  68. [68]
    Details for Satellite Programme: RISAT - WMO OSCAR
    Programme description. Series of two experimental satellites for SAR observation. Indian programme: ISRO responsible of development and operations.
  69. [69]
    Utility Software - NRSC
    Software is developed at Microwave Remote Sensing and Data Processing ... Research Organiation for registration of RISAT-1 multidate data. The utility ...
  70. [70]
    High-Resolution Operational Soil Moisture Product, now an ... - ISRO
    Feb 7, 2024 · This innovative product promises a spatial resolution of 500 meters, a significant leap forward in soil moisture monitoring for agricultural applications.
  71. [71]
    [PDF] indian space research organisation - ISRO
    The antenna is adapted to be installed in a Radar Imaging Satellite (RISAT) ... an image capturing system for monitoring the positioning of each satellite in the.