The deployment of NISAR’s massive radar antenna in space is an intricately choreographed engineering sequence that epitomizes modern space technology. After a precision launch aboard ISRO’s GSLV-F16 rocket from Sriharikota, the satellite entered a Sun-synchronous polar orbit. With the craft safely in orbit, ISRO and NASA controllers began a carefully staged 90-day commissioning phase, of which the antenna’s deployment is a central focus.

Antenna Deployment: Engineering Like Origami

NISAR’s 12-meter (39-foot) wide gold-plated wire mesh reflector, attached to the end of a 9-meter boom, is too large to fit inside any rocket fairing in its operational form. Therefore, it was meticulously folded—akin to an origami camp chair—into a compact configuration for launch. Once in orbit, engineers initiate a multi-step, sequenced deployment process designed to maximize safety and ensure perfect alignment.

Multi-Step Unfolding Sequence

Day 10–18 Post Launch: The deployment phase begins on Mission Day 10, termed "Deploy Day 1" (DD-1). The process starts with system checks and the unlocking of six launch restraints, each vital for securing the antenna during launch vibrations and shocks.

Sequential Boom Extension: Over successive days, additional restraints are released and a series of hinged extensions—reminiscent of the movements in an arm—are activated. First, the "wrist hinge" unfolds (DD-2), followed by the shoulder and elbow hinges (DD-3 and DD-4). Each step swings the boom further outward.

Full Boom Extension And Pauses: Once the root hinge is deployed (DD-5), the boom reaches full extension, holding the antenna far from the satellite body. The team builds in deliberate pauses (DD-6) to analyse telemetry, confirm the integrity and correct any misalignment.

Orientation And Final Unfurling: After a buffer day to address possible delays or issues, NISAR performs a "yaw manoeuvre" to ensure the body and boom are perfectly oriented. Only then is the reflector—a vast mesh disk—gently opened like an umbrella (DD-8).


Safety and Verification At Every Step

Throughout this process, spacecraft controllers closely monitor data to verify structural integrity, proper deployment, and alignment. Each stage can be halted or adjusted if anomalies are detected. This caution is crucial because even a slight malfunction could compromise the entire mission.

Why The Unfolding Matters

This colossal antenna forms the heart of NISAR’s Earth observation mission. It focuses radar signals from both NASA’s L-band (24 cm wavelength) and ISRO’s S-band (10 cm wavelength) radars, enabling the satellite to capture detailed images of our planet’s surface, including subtle movements undetectable by other means. The dual-frequency system can “see” through clouds, vegetation, and even darkness—critical for comprehensive monitoring of natural disasters, land deformation, ice dynamics, and ecosystem changes.

Mission Impact

Once the deployment and subsequent calibration is complete, NISAR will commence science operations, mapping the entire planet every 12 days. This unparalleled temporal and spatial resolution will allow scientists to generate time-series interferometric imagery, systematically illuminating Earth’s dynamic processes with unprecedented fidelity.

In essence, the origami-like unfolding of NISAR’s antenna in space is more than a feat of mechanical engineering—it’s the gateway to a new era in global Earth observation.

Based On India Today Report