After a Decade in the Making, NASA-India’s NISAR Radar Satellite Launches Monday

Unprecedented U.S.–India Collaboration in Earth Observation

On Mon­day, July 28 2025, the NASA-ISRO Syn­thet­ic Aper­ture Radar (NISAR) satel­lite lifts off aboard ISRO’s GSLV-F16 from Satish Dhawan Space Cen­tre in Sri­hariko­ta, mark­ing the cul­mi­na­tion of more than ten years of joint devel­op­ment between NASA and the Indi­an Space Research Organ­i­sa­tion (ISRO). NISAR rep­re­sents the first equal-part­ner Earth-obser­va­tion mis­sion between the two agen­cies, com­bin­ing NASA’s L‑band and ISRO’s S‑band radars on a sin­gle plat­form.

Dual-Frequency SAR for All-Weather, Day-Night Imaging

NISAR’s dual-fre­quen­cy syn­thet­ic aper­ture radar (SAR) pay­load com­pris­es:

• NASA’s L‑band radar (24 cm wave­length), capa­ble of pen­e­trat­ing veg­e­ta­tion and soil
• ISRO’s S‑band radar (9.3 cm wave­length), opti­mized for mon­i­tor­ing mois­ture and sur­face fea­tures

These com­ple­men­tary radars share a 12 m deploy­able mesh reflec­tor anten­na, enabling high-res­o­lu­tion imag­ing through clouds and dark­ness. Togeth­er, they will scan near­ly all of Earth’s land and ice sur­faces twice every 12 days, gen­er­at­ing approx­i­mate­ly 80 TB of data per day for sci­en­tif­ic and oper­a­tional use.

SweepSAR Technology and Global Coverage

Using Sweep­SAR tech­nol­o­gy, NISAR achieves a swath width of 242 km with spa­tial res­o­lu­tions between 5 and 10 m. Its Sun-syn­chro­nous orbit at 743 km alti­tude and 98.4° incli­na­tion allows con­sis­tent revis­it inter­vals and repeat-pass inter­fer­om­e­try, essen­tial for mea­sur­ing ground defor­ma­tion, ice-sheet dynam­ics, and veg­e­ta­tion changes at sub-cen­time­ter pre­ci­sion.

Key Science Objectives and Applications

NISAR’s data will sup­port a broad array of dis­ci­plines and appli­ca­tions:

• Nat­ur­al haz­ard mon­i­tor­ing: Detect sub­tle land move­ments pre­ced­ing earth­quakes, land­slides, and vol­canic erup­tions, improv­ing ear­ly warn­ing sys­tems.
• Cryos­phere stud­ies: Track Antarc­tic and Arc­tic ice-sheet retreat and glac­i­er flow to refine cli­mate mod­els.
• Ecosys­tem assess­ment: Map for­est struc­ture, wet­land dynam­ics, and soil mois­ture changes for resource man­age­ment and agri­cul­tur­al plan­ning.
• Dis­as­ter response: Pro­vide near-real-time imagery to aid emer­gency relief dur­ing floods, wild­fires, and storm surges.

Engineering Milestones and Decade-Long Development

The NISAR project epit­o­mizes inter­na­tion­al coop­er­a­tion:

• NASA sup­plied the L‑band SAR, high-rate teleme­try, GPS receivers, and pay­load data sub­sys­tems.
• ISRO pro­vid­ed the S‑band SAR, satel­lite bus, solar arrays, and the GSLV-F16 launch vehi­cle.
• Over­com­ing design challenges—such as anten­na ther­mal coatings—required iter­a­tive test­ing between JPL and ISRO teams, cul­mi­nat­ing in final inte­gra­tion at Satish Dhawan in May 2025.

Impact and Data Accessibility

With an esti­mat­ed mis­sion cost of US $1.5 bil­lion, NISAR is poised to be the world’s most expen­sive and capa­ble Earth-imag­ing radar satel­lite. All data will be freely avail­able with­in 24 hours of acqui­si­tion (and with­in hours dur­ing emer­gen­cies), democ­ra­tiz­ing access for researchers, gov­ern­ments, and com­mer­cial enti­ties world­wide.

As NISAR embarks on its sci­en­tif­ic jour­ney, it stands as a tes­ta­ment to the pow­er of sus­tained inter­na­tion­al col­lab­o­ra­tion in address­ing glob­al challenges—from cli­mate change to dis­as­ter resilience—using cut­ting-edge radar tech­nol­o­gy.