NISAR (NASA-ISRO Synthetic Aperture Radar)

The first dual-frequency L-band + S-band SAR mission in orbit. NASA + ISRO joint program; ~14 years of joint development; launched July 2025; 100,000+ products released through ASF DAAC by February 2026. Expected to generate ~140 PB over its 3-year baseline mission — roughly the size of NASA’s entire current Earth-data archive, doubled, from this one satellite.

What it sees

• L-band SAR (24 cm wavelength) — penetrates vegetation canopies and dry soil; longer wavelength → InSAR coherence persists over months instead of days; ideal for forest biomass, ice-sheet flow, slow tectonic deformation.
• S-band SAR (9 cm wavelength) — complementary information layer; sensitive to surface scatterers; agricultural monitoring focus.
• Polarimetric: full quad-pol + dual-pol acquisition modes.

Why it matters

• The first time the world has continuous global L-band SAR at scale — historically L-band has been intermittent (SEASAT 1978, JERS-1 1992–1998, ALOS 2006–2011, ALOS-2 commercial).
• L-band wavelength enables science questions C-band cannot answer: above-ground forest biomass without saturation, multi-decade ice flow, deep soil moisture penetration, long-baseline InSAR.
• Co-funded mission — ISRO contributes the spacecraft bus + S-band radar + launch; NASA contributes the L-band radar + payload electronics. Demonstrates large-scale agency-to-agency open-data partnership.

Where to get the data

• ASF DAAC Vertex: search.asf.alaska.edu (same as Sentinel-1 path)
• earthaccess: short names beginning NISAR_* (verify via CMR — naming was settling as of Feb 2026)
• OPERA-style ARD products in development; raw RSLC is current.

What it enables (largely new science)

• Above-ground biomass at hectare scale globally (every 6–12 days) — closes a gap GEDI samples but doesn’t cover continuously
• Ice-sheet velocity mapping with sub-week cadence (Antarctica + Greenland)
• Slow earthquake / interseismic strain accumulation via L-band InSAR (years-long coherence)
• Soil moisture under vegetation (L-band penetrates canopy)
• Crop classification and growth-stage monitoring (S-band)

Gotchas

• Brand new. Conventions still being defined — NISAR STAC convention is being negotiated post-launch (cmr-stac issue #413). Documentation patchy.
• Volume is staggering. 140 PB / 3 years = ~128 TB/day; cloud-native access is mandatory. Plan storage + transfer carefully.
• L-band data is not like C-band data. Different scattering physics; existing Sentinel-1 pipelines will not produce sensible results when pointed at NISAR L-band.
• No mature analysis-ready product yet. Expect 12–18 months before the equivalent of OPERA RTC-S1 exists for NISAR. Early adopters pay the burden of working with raw L1.

Related missions

• Sentinel-1 — C-band complement; pair for dual-frequency analyses.
• GEDI (on ISS, lidar): footprint biomass + canopy structure; NISAR + GEDI together is the new global-forest-carbon stack.
• ALOS-4 (JAXA): commercial L-band, complementary acquisition strategy.

Related datasets