Lithium-ion batteries for satellites: what are the advantages for long missions?

In the vast expanse of space, where missions can span decades and conditions are relentlessly extreme, a satellite's power source is not merely a component but the very lifeline of its operation. The success and longevity of critical missions, from Earth observation to deep-space exploration, hinge on reliable, high-performance energy storage. While space applications traditionally relied on Nickel-Cadmium (Ni-Cd) and Nickel-Hydrogen (Ni-H2) batteries, the dawn of the 21st century ushered in a new era, with lithium-ion satellite battery technology emerging as the undisputed champion for the majority of satellite projects and specifically for long-duration space missions.

Lithium-ion batteries have become the preferred choice for powering satellites due to their unparalleled advantages in energy density, cycle life, and resilience to harsh space environments. Saft was a pioneer qualifying the Li-Ion technology for space applications at the end of the 90’s despite the huge requirements. Saft's pivotal role and extensive heritage in this specialized field showcase a proven track record and commitment to energizing the future of space exploration.

The critical role of batteries in space missions

Space is an unforgiving environment, presenting unique and formidable challenges for any technology. As the sole source of power during orbital eclipses, batteries must contend with the mechanical constraints during the launch, the vacuum of space, vast temperature fluctuations, and constant radiation exposure. For satellites in Low Earth Orbit (LEO), this means enduring thousands of charge/discharge cycles, demanding exceptional cycle life and reliability. Moreover, for the new satellite generation so called “full electrical”, the batteries must deliver the power to the plasmic propulsion system in addition to the main mission to provide power to the satellite during eclipse.

The continuous availability of power is non-negotiable. Any interruption can lead to mission failure, making the selection of satellite batteries subject to the most stringent requirements for reliability, longevity, and performance under the immense stress of a rocket launch and the harsh conditions of orbit. In space, no maintenance and repair are possible as per for all ground applications.

Key Takeaways:

• Batteries are essential for the satellite's lifetime, providing essential power during orbital eclipses.
• They must withstand extreme conditions: mechanical (shocks, vibrations), vacuum, radiation, and massive temperature swings.
• Uninterrupted power is critical, as any failure can result in the complete loss of the mission.

Why lithium-ion is the preferred choice for long-duration space missions?

The ascendancy of lithium-ion (Li-ion) technology in space applications is a testament to its inherent advantages over previous battery chemistries. These benefits directly address the stringent demands of long-duration missions, offering a compelling blend of performance, efficiency, and reliability.

Saft's pioneering legacy and future in space batteries

Saft's involvement in space exploration spans over half a century, beginning in 1966 with the launch of the first French satellite, Diapason 1A, equipped with Saft's Nickel-Cadmium (Ni-Cd) batteries. This legacy of innovation continued with the development of reliable Nickel-Hydrogen (Ni-H2) batteries in the 1980s and a pivotal shift to Li-ion technology in the early 2000s. Saft have provided batteries with these three technologies for a total of more than 1400 satellites since 1966.

Today, Saft has achieved a remarkable milestone, having energized over 400 satellites with its advanced battery technology, representing over 3.7 billion operating hours in space. This extensive flight heritage is a testament to the reliability and performance of Saft’s solutions.

Key Takeaways:

• Saft has close to 60 years of space heritage, starting with the first French satellite launched in 1966.
• The company has powered over 1400 satellites, accumulating over 3.7 billion operating hours without any failure.
• Saft's batteries are trusted for critical missions, from global telecommunications to deep-space exploration.

Beyond 2025: powering future space exploration

As space exploration pushes new boundaries, the demand for more advanced and specialized battery solutions intensifies. Saft is actively engaged in powering the next generation of space missions by refining existing Li-ion technologies and investing in cutting-edge research such as Solid-state technology that will permit to increase the cell specific energy above 400 Wh/kg. This technology will be qualified for the beginning of the next decade.

One other significant area of focus is Lithium Titanate Oxide (LTO) chemistry. LTO batteries offer unique advantages for applications requiring extremely long cycle life, very high charge/discharge rates, and enhanced safety. While LTO has a lower energy density, its ability to operate across a wide temperature range makes it ideal for aggressive LEO cycling demands, such as those found in radar satellites.

Key Takeaways:

• Future missions require even more specialized battery solutions.
• Saft is investing in next-gen chemistries like Solid-state batteries and LTO for high-cycle and high-power applications.
• This forward-looking strategy ensures Saft remains at the forefront of energizing humanity's journey into space.

Conclusion

Lithium-ion technology has fundamentally transformed satellite design since 2000, enabling longer missions, greater capabilities, and more cost-effective access to space. With a deep-rooted legacy of innovation and an unparalleled flight heritage, Saft continues to lead this charge, developing robust and reliable power solutions that meet the critical demands of the global space industry. As humanity's ambitions in space grow, Saft's advanced batteries will remain the lifeline for the missions of tomorrow.