One wing span stretches wider than a football field, yet the craft weighs less than a NFL linebacker. Radical aims to redefine how data is gathered from above by building a solar-powered drone that can linger in the stratosphere for months at a time. This is not a satellite waiting to be launched into orbit; it is a lightweight airframe designed to stay in the sky, powered by the sun and capable of autonomous operation.

Evenstar Signals a New Class of Sky Infrastructure

What Evenstar Is Trying to Do

Radical, a Seattle-based startup, unveiled a full-scale prototype with a 120-foot wingspan and a frame that weighs roughly 240 pounds. Its distinctive boomerang shape, coupled with ultra-light construction, is meant to maximize endurance while keeping production costs manageable. The core idea is to pair high-altitude persistence with high-resolution sensing, enabling continuous monitoring for weather, connectivity, and intelligence tasks without the traditional limits of drones or satellites.

Evenstar carries a 33-pound payload and relies on solar panels mounted on its wings to power flight. The company envisions a system that can remain airborne for weeks or months, returning to Earth when it needs maintenance or upgrades. The most recent test in Tillamook, Oregon was autonomous, with a human pilot ready to intervene if necessary. In a battery-powered ballast test, Radical simulated the added weight the final solar-equipped version would carry, a common step in validating flight dynamics before high-altitude trials.

According to Popular Science, the Tillamook flight was conducted at low altitude and at speeds a little over 15 miles per hour. The performance data gathered in these early trials are meant to inform the next phase of testing at higher elevations and with solar power fully engaged. As Radical CEO James Thomas told the outlet, the mission is to make stratospheric flight routine in the same way satellite operations are today, but at higher resolution and lower cost.

For readers and defense planners, the message is clear: a lightweight, solar-powered airframe could become a persistent sensor and communications platform with fewer constraints than traditional aircraft or orbital satellites. It’s a bold bet on autonomy, AI-driven control, and robust telemetry that can adapt on the ground as needs shift. Reader-facing note: the implications span civil, commercial, and potentially military applications, depending on how quickly the technology scales and how regulators respond.

The StratoSat Concept: A Middle Ground Between Satellites and Drones

Radical has framed Evenstar as part of a family of devices it calls StratoSats—essentially satellite-like platforms that can hover in the stratosphere, collect data, and beam it down via robust telemetry links, while still being recoverable and upgradable. The solar-powered design is central: wings that collect sunlight supply power for weeks on end, reducing the need for frequent refueling missions and enabling more continuous data collection than most conventional drones can sustain. The ability to remain aloft for extended periods could unlock higher-throughput sensing, better weather surveillance, and more resilient ground connectivity in remote regions.

Evenstar’s payload capacity—33 pounds—lets operators equip it with sensors, cameras, or lightweight telecom equipment without tipping the balance toward heavyweight airframes. Radical’s team, which includes veterans from Amazon Prime Air, argues that the system’s longevity and autonomous flight are what will eventually separate StratoSats from both pure satellites and standard drones. The company emphasizes that the platform can return for maintenance and payload swaps, reducing the lifecycle cost of repeated satellite launches for certain applications.

Industry observers note that Evenstar sits in a crowded field of solar-powered, long-endurance programs. Airbus is already testing Zephyr, a solar-powered drone that has demonstrated multi-week operations in the past, and US startup Skydweller is pursuing a similar concept with a heavier, cargo-capable form. Radical’s approach is notably compact—six-person team and lean hardware—to bring down development risk while pursuing a very ambitious endurance target. It’s a reminder that the race to the stratosphere is becoming a multi-player, mixed-mission space for data and connectivity rather than a single, rigid path to orbit. According to Popular Science’s reporting, the company plans higher-altitude tests next year to push the platform toward real-world operating conditions.

What This Could Mean for the Industry

If Evenstar achieves its endurance goals, the drone could become a flexible, cost-effective alternative to satellite constellations for certain tasks. That would shift how companies think about data refresh rates, regional coverage, and the economics of continuous observation. It could also redefine public-private partnerships—governments and commercial operators may co-develop StratoSat capabilities for disaster response, wildfire monitoring, and rural connectivity projects. The broader implication is a more dynamic, layered approach to sky infrastructure where drones supplement or replace certain satellite functions, rather than simply orbit alongside them.

From a policy perspective, regulators will need to grapple with the implications of persistent aerial platforms that operate across national airspace, at altitudes where weather and aviation rules collide. Privacy, data ownership, and airspace coordination will be central debates as more players propose stratospheric data services rather than traditional remote-sensing corridors. As the field matures, operators will push for clear standards on endurance, autonomous control, and safety testing so that these systems can scale without compromising airspace safety or civil liberties.

Industry Takeaways

• Long-endurance, solar-powered design is shifting the cost curve of sky data
• StratoSats could complement satellites by offering higher-resolution, persistent coverage
• Regulatory clarity will determine how quickly these platforms scale commercially

Conclusion

The Evenstar project shows that the frontier of unmanned flight is moving upward and outward, toward the stratosphere, where solar power and autonomous control converge. Whether Radical’s approach becomes a practical path to months-long, persistent sky infrastructure remains to be seen, but the seeds of a new class of aerial platforms are clearly in the ground. As the industry watches, expect more players to test, compare, and refine the idea of a persistent aerial layer that sits between drones and satellites.