The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

and

ISRO The Indian Space Research Organisation (ISRO ) is India's national space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), overseen by the Prime Minister o ...

to co-develop and launch a dual-frequency

Synthetic Aperture Radar Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or 3D reconstruction, three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target regi ...

(SAR) on an

Earth observation satellite An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, me ...

in 2025. It will be the first

radar imaging Radar is a system that uses radio waves to determine the distance (''ranging''), direction (geometry), direction (azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to det ...

satellite to use dual frequencies. It will be used for

remote sensing Remote sensing is the acquisition of information about an physical object, object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring inform ...

, to observe and understand natural processes on

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. For example, its left-facing instruments will study the

Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...

cryosphere The cryosphere is an umbrella term for those portions of Earth's surface where water is in solid form. This includes sea ice, ice on lakes or rivers, snow, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost). Thus, there ...

. With a total cost estimated at US$1.5 billion, NISAR is likely to be the world's most expensive Earth-imaging satellite.

Overview

The NASA-ISRO

, or NISAR satellite, will use advanced radar imaging to map the elevation of Earth's land and ice masses four to six times a month at resolutions of 5 to 10 meters. It is designed to observe and measure some of the planet's most complex natural processes, including ecosystem disturbances, ice-sheet collapse, and natural hazards such as

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

es and

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

s. The mission is a partnership between

and

. Under the terms of the agreement, NASA will provide the mission's

L-band The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of Frequency, frequencies in the radio spectrum from 1 to 2 gigahertz (GHz). This is at the top end of the ultra high frequency (UHF) band, at t ...

synthetic aperture radar Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or 3D reconstruction, three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target regi ...

(SAR), a high-rate telecommunication subsystem for scientific data

GPS receivers A satellite navigation (satnav) device or GPS device is a device that uses satellites of the Global Positioning System (GPS) or similar global navigation satellite systems (GNSS). A satnav device can determine the user's geographic coordinates ...

, a solid-state recorder, and a payload data subsystem. ISRO will provide the

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are less customized than specially-produced satelli ...

, an

S-band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the convention ...

(SAR), the launch vehicle, and associated launch services. All data from NISAR will be freely available one to two days after observation and within hours in case of emergencies like natural disasters. Data collected from NISAR will reveal information about the evolution and state of

Earth's crust Earth's crust is its thick outer shell of rock, referring to less than one percent of the planet's radius and volume. It is the top component of the lithosphere, a solidified division of Earth's layers that includes the crust and the upper ...

, help scientists better understand our planet's natural processes and changing climate, and aid future resource and hazard management. The satellite will be

three-axis stabilized Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle or satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, ...

. It will use a deployable mesh antenna and will operate on both the L- and S- microwave bands. The aperture mesh reflector (antenna) will be supplied by Astro Aerospace. The National Centre of Geodesy facilities at IIT-Kanpur and IIT-Patna will host a

corner reflector A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat reflective surfaces. It reflects waves incident from any direction directly towards the source, but translated. The three intersecting surfa ...

for NISAR.It will play a key role in calibration and course correction of the Nisar satellite's radar during the in-orbit checkout phase. ISRO's share of the project cost is about , and NASA's share is about US$1,118 million.

Launch

The satellite was originally scheduled to be launched from India aboard a GSLV Mark II on 30 March 2024, but it was postponed until further notice due to a needed hardware update. The orbit will be a

Sun-Synchronous Orbit A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is ...

(SSO), dawn-to-dusk type. The planned mission life is three years. The satellite was fully integrated in January 2024 and was performing its final testing and analysis in preparation for launch. However, in an interview with the ''

Times of India ''The Times of India'' (''TOI'') is an Indian English-language daily newspaper and digital news media owned and managed by the Times Group. It is the List of newspapers in India by circulation, third-largest newspaper in India by circulation an ...

'', Chairman of ISRO Sreedhara Panicker Somanath said that though the GSLV for NISAR will be built by March-April, the satellite is still undergoing tests and they were expecting some delay. Tests found that the reflector might face higher-than-expected temperatures when stowed during flight and so it was returned to the manufacturer in California to apply a reflective coating to mitigate the risk of overheating. On 15 October 2024, after the completion of all checks and tests, NASA's

C-130 The Lockheed C-130 Hercules is an American four-engine turboprop military transport aircraft designed and built by Lockheed Corporation, Lockheed (now Lockheed Martin). Capable of using unprepared runways for takeoffs and landings, the C-130 w ...

took off from

Wallops Flight Facility Wallops Flight Facility (WFF) is a rocket launch site on Wallops Island on the Eastern Shore of Virginia, United States, just east of the Delmarva Peninsula and approximately north-northeast of Norfolk, VA, Norfolk. The facility is operated ...

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

to embark on the multi-leg, multi-day journey to India. The flight will first stop at

March Air Reserve Base March Air Reserve Base (March ARB), previously known as March Air Force Base (March AFB), is located in Riverside County, California, between the cities of Riverside, California, Riverside, Moreno Valley, California, Moreno Valley, and Perri ...

to retrieve the spacecraft followed by strategic stops at

Hickam Air Force Base Hickam Air Force Base is a United States Air Force (USAF) United States Air Force installation, installation, named in honor of aviation pioneer Lieutenant Colonel (United States), Lieutenant Colonel Horace Meek Hickam. The installation merged ...

, Hawaii;

Andersen Air Force Base Andersen Air Force Base (Andersen AFB, AAFB) is a United States Air Force base located primarily within the village of Yigo in the United States territory of Guam. The host unit at Andersen AFB is the 36th Wing (36 WG), assigned to the Pacif ...

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

;

Clark Air Base Clark Air Base is a Philippine Air Force base in Luzon, located west of Angeles City, and about northwest of Metro Manila. It was previously operated by the U.S. Air Force and, before that, the U.S. Army, from 1903 to 1991. The base cov ...

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

and reach

HAL Airport HAL Airport is an airport that serves Bengaluru, the capital of the Indian state of Karnataka. Located about 12 km east of the city centre, it has one runway and operates 24/7. Hindustan Aeronautics Limited (HAL), a state-owned defence c ...

Bengaluru Bengaluru, also known as Bangalore (List of renamed places in India#Karnataka, its official name until 1 November 2014), is the Capital city, capital and largest city of the southern States and union territories of India, Indian state of Kar ...

, India. By late January 2025, the satellite had finished all preliminary checkout in Bengaluru and was shipped to SDSC. As of December 2024, NISAR is expected to be launched in 2025.

Gallery

NISAR diagram.jpg, NISAR diagram File:NASA-ISRO NISAR satellite inside anechoic chamber at URSC, ISRO.webp, NISAR undergoing tests File:NASA-ISRO NISAR satellite going through solar array extension testing at ISRO facility.webp, NISAR solar array File:NASA-ISRO NISAR satellite's DGA antenna.webp, NISAR's DGA antenna

Payload

(1.25

GHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...

; 24 cm wavelength)

polarimetric Polarimetry is the measurement and interpretation of the polarization of transverse waves, most notably electromagnetic waves, such as radio or light waves. Typically polarimetry is done on electromagnetic waves that have traveled through or hav ...

SAR, to be produced by NASA. *

(3.20 GHz; 9.3 cm wavelength) polarimetric SAR, to be produced by ISRO.

References

{{Future spaceflights ISRO satellites Proposed NASA satellites India–United States relations 2025 in spaceflight Synthetic aperture radar satellites

Overview

Launch

Gallery

Payload

See also

References