Helios Horizon, a Florida-based nonprofit, has completed what it claims is the first piloted flight of an electric aircraft using solid-state batteries.

On June 5, founder and chief test pilot Miguel Iturmendi conducted a series of short test flights at Zephyrhills Municipal Airport in central Florida aboard a modified Pipistrel Taurus motor glider designated as the Helios Horizon.

The aircraft, previously equipped with lithium-ion batteries rated at 260 Wh/kg, was reconfigured to run on solid-state batteries delivering 410 Wh/kg.

According to the organization, these new cells are smaller than typical lithium-ion packs used in modern electric vehicles yet provide 60 to 80 percent greater energy density.

Helios Horizon performs first flight with solid-state batteries

Solid-state batteries replace the flammable liquid electrolyte found in conventional lithium-ion cells with a solid material.

This design allows for enhanced thermal stability and resistance to physical damage such as punctures. The batteries can draw power from standard AC electrical sources without specialized charging infrastructure. In flight, the aircraft can supplement its energy through integrated solar panels and by operating the propeller as a wind turbine during non-powered segments.

According to Helios Horizon, their solid-state batteries charge from near-empty to 80 percent capacity in less than 15 minutes. The organization is also aiming for further improvements of around 40 percent in energy density within two years.

“For the first time, we have a battery technology that yields the range and charging times necessary to make commercial electric aviation viable, while providing the safety the flying public will demand,” Iturmendi said in a statement.

He added that regenerative techniques, including gliding and windmilling the propeller during descents, “can significantly increase the range of the airplane.”

The June 5 flights primarily validated weight and balance after the battery installation, according to a post from RobbReport. The new power system performed better than expected during sustained operation, though specific range and top speed figures were not disclosed.

The future of solid-state battery aircraft

The Helios Horizon previously set a class altitude record at 24,000 feet. The team now plans stratospheric flights later this year, targeting altitudes above 40,000 feet—higher than typical passenger airliner cruise levels. Iturmendi believes the solid-state batteries will enable these missions on a single charge.

At this stage, the Helios Horizon serves as a technology demonstrator to illustrate potential gains in range and endurance for electric propulsion. While not intended for immediate commercial production, the project highlights progress toward practical electric aircraft that address key limitations in energy storage and safety.

The achievement arrives amid broader industry efforts to develop viable electric and hybrid propulsion for aviation. Solid-state technology has long been viewed as a potential breakthrough, promising higher performance and improved safety margins over current battery chemistries. Helios Horizon’s test marks a tangible step in applying that technology to a manned aircraft.

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As global space operations continue to expand, the reliable provision of power to satellites and spacecraft is becoming increasingly important.

In a bid to tackle this problem, the Japan Aerospace Exploration Agency (JAXA) has selected Tokyo-based firm Maxell for its Space Technologies Rapid Evaluation Program on Small Satellite (JAXA-STEPS).

Under the agreement, Japanese battery manufacturer Maxell will collaborate with the space agency on the development and demonstration of high-heat-resistant all-solid-state batteries designed to improve performance in space environments.

JAXA’s new space battery project

Maxell’s motto, “Micro batteries. Maximum impact,” emphasizes the firm’s strategy of delivering substantial value in a compact form factor. The company has highlighted four key benefits of all-solid-state batteries: long life, high heat resistance, high output, and large capacity.

The collaborative project, meanwhile, aims to achieve two main goals. Titled ‘Development and Demonstration of High-Heat-Resistant All-Solid-State Batteries to Maximize Spacecraft Missions’, its aim is to reduce the overall weight of small satellites and increase their design flexibility. 

Weight is practically a currency in space. Reducing the use of heavy machinery can drastically lower the cost of a space mission. It can also allow for more scientific, military, or other payloads to fly to space in a single launch.

Traditional spacecraft require extensive temperature control systems due to extreme temperature swings in space. All-solid-state batteries that operate reliably at high temperatures have the potential to cut the need for such equipment.

Maxell has developed all-solid-state batteries capable of maintaining high safety levels at temperatures above 100°C (212°F). In the joint research, the company aims to match the energy density of conventional lithium-ion batteries while delivering stable output and long service life across the wide temperature ranges encountered in orbit. Demonstration units will be prepared for potential installation in satellites.

JAXA-STEPS is accelerating the testing of technologies critical to future missions by using small satellites for rapid demonstrations. The program supports both public and private sector advancements. By minimizing thermal management hardware, the new batteries could allow satellites to carry more payload or reduce launch costs through lower mass.

Advanced battery chemistries

The JAXA-Maxell collaboration reflects growing interest in advanced battery chemistries for demanding applications. All-solid-state designs replace liquid electrolytes with solid materials, offering potential advantages in safety, thermal stability, and energy density. If the technology is proven in space, it could also benefit other high-reliability sectors, including industrial equipment and extreme-environment electronics.

Maxell plans to expand the applications for its all-solid-state batteries and accelerate the development of solutions tailored to customer needs. Details of the selection were outlined in a company press statement.

Reliable, lightweight power systems remain a persistent engineering challenge. This initiative aims to address the problem as the space industry continues to grow, with an increasing number of small satellites deployed for communications, Earth observation, and scientific research. Maxell’s work with JAXA could contribute to more efficient and robust satellite platforms.

NASA is preparing to send the next Artemis astronauts to space. Though Artemis III won’t land on the moon, it will be the final preparation mission before Artemis IV and V finally land humans on the lunar surface for the first time since 1972.

Ahead of that mission, Northrop Grumman has transported the last eight solid rocket booster motor segments to the Kennedy Space Center in Florida by train. 

The boosters, which will eventually generate 7.2 million pounds of thrust at liftoff, will be stacked this summer.

Northrop Grumman’s SLS booster delivery

Northrop Grumman transported the booster segments from its facility in Promontory. These will join segments already delivered in April. Together, they will be the first hardware stacked on NASA’s mobile launch platform this summer, ahead of Artemis III.

Northrop Grumman manufactures the twin five-segment solid rocket boosters that form the most powerful human-rated motors ever built. Together, they generate 7.2 million pounds of thrust at liftoff, supplying the majority of the power for NASA’s Space Launch System (SLS) rocket during the initial ascent.

If all goes to plan, Artemis III will be a key step toward sustained lunar exploration and future crewed missions to Mars.

Artemis III will send astronauts to low Earth orbit aboard the Orion spacecraft. Once there, they will conduct rendezvous operations with human landing systems.

Though preparations are well underway, the recent explosion of Blue Origin’s New Glenn rocket, which was due to fly its Mk 1 lander to the moon later this year, could prove to be a major setback as NASA aims to beat China to the lunar surface.

Flying back to the Moon

NASA’s SLS program has faced criticism for delays and overspending, as well as for its reliance on old technologies.

According to Northrop Grumman, though, its solid rocket motors have been proven over decades, having served the Space Shuttle program. 

The legacy contractor notes that the motors delivered this month also incorporate modern enhancements for greater performance and reliability. The boosters successfully lifted both Artemis I and II.

In a press statement, Northrop Grumman highlighted the role of its manufacturing facilities and skilled workforce as key factors enabling these crucial missions.

This capacity will support NASA’s planned increase in Artemis launch cadence while also addressing national security requirements.

Each of the boosters consists of three major assemblies, with the motor segments representing the largest portion. Technicians at the Utah site prepared the hardware, including one center segment featuring NASA’s iconic “worm” logo.

Once at Kennedy Space Center, technicians will assemble the boosters before linking them with the SLS core stage and other elements. The full stack will eventually launch the crewed Orion vehicle toward the Moon.

According to Northrop Grumman, this delivery completes the preparation of booster hardware for Artemis III. It reflects steady progress in NASA’s effort to return humans to the lunar surface. 

If that mission is a success, Artemis IV will then aim to land astronauts near the lunar south pole, where water ice and other resources could support a long-term human presence.

Northrop Grumman continues to produce boosters for upcoming Artemis missions. According to the firm, it has the capacity to “accelerate solid rocket motor production to meet NASA’s increased Artemis mission launch cadence”.