Sky Skimmers: Racing to the Lowest Orbit

A new space race is unfolding, not in the distant cosmos, but just above us—at the very edge of Earth's atmosphere.

For decades, satellites have been launched into high orbits, circling Earth from hundreds or even thousands of kilometers above. Now, a new space race is emerging—one that aims to operate satellites at lower altitudes than ever before. Companies and space agencies worldwide are pushing the limits of technology to develop satellites that can function in very low Earth orbit (VLEO), a region spanning approximately 150 to 300 kilometers above the planet’s surface.

Why Go Lower?

The motivation behind flying satellites at lower altitudes is multifaceted. First, VLEO allows for significantly higher-resolution Earth observation. At these low orbits, imaging satellites can capture finer details on the ground, which is beneficial for applications such as environmental monitoring, disaster response, and military surveillance. Lower altitudes also enable reduced communication latency, improving real-time data transmission for internet and telecommunication services.

Another advantage is the ability to operate smaller and more cost-effective satellites. Since VLEO satellites require less energy to reach orbit, they can be launched using lighter, less expensive rockets. Moreover, these satellites naturally deorbit within months or years due to atmospheric drag, reducing the long-term issue of space debris accumulation.

Challenges of Very Low Earth Orbit

Despite its advantages, VLEO presents significant technical challenges. The primary hurdle is atmospheric drag, which increases exponentially at lower altitudes. This drag can rapidly slow down satellites, causing them to fall back to Earth unless they are equipped with efficient propulsion systems. To counteract this, researchers are developing novel propulsion techniques, including ion thrusters and air-breathing engines that use the scarce atmospheric particles at these altitudes.

Another issue is the exposure to denser atmospheric particles, which can lead to increased material degradation and electrical charging. Engineers are working on advanced materials and shielding techniques to mitigate these risks and extend satellite lifespans.

Key Players in the VLEO Space Race

Several companies and government agencies are at the forefront of developing VLEO technology. European space company Thales Alenia Space is actively researching air-breathing propulsion systems that could enable sustained low-altitude operations. Meanwhile, American aerospace firms, including Lockheed Martin and Northrop Grumman, are investing in VLEO-capable military reconnaissance satellites for enhanced battlefield intelligence.

Startups such as Earth Observant and Albedo Space are also entering the competition, focusing on commercial applications such as ultra-high-resolution imaging for urban planning and climate studies. Additionally, China and Russia have expressed interest in deploying reconnaissance and communications satellites in VLEO to strengthen their strategic capabilities.

Recent Breakthroughs and Test Missions

In recent years, several test missions have demonstrated the feasibility of VLEO operations. In 2017, Japan’s Tsubame satellite operated successfully at altitudes as low as 167 kilometers, using an ion engine to counteract atmospheric drag. More recently, NASA’s Pathfinder mission has been experimenting with new materials and propulsion systems designed for VLEO endurance.

The European Space Agency (ESA) is also working on the Skimsat project, which aims to deploy an operational satellite in VLEO with extended mission longevity. These experimental efforts are paving the way for future commercial and military applications in this challenging orbital environment.

The Future of VLEO Satellites

As technology advances, the dream of maintaining sustainable operations in VLEO is becoming more realistic. Continued research into advanced propulsion, aerodynamics, and resilient materials will be critical to overcoming the challenges posed by the lower atmosphere.

If successful, VLEO satellites could revolutionize Earth observation, global communications, and space-based intelligence, making access to space cheaper, faster, and more efficient than ever before. As companies and nations continue to push the boundaries, the race to fly satellites at the lowest orbits yet is only just beginning.