VLEO Satellite Development and Remote Sensing: A Multidomain Review of Engineering, Commercial and Regulatory Solutions

1. Introduction

Earth observation and remote sensing technologies have transitioned within the past sixty years from experimental tools to essential capabilities for applications across the science, economic, environmental, and commercial sectors. Remote sensing has become recognized for its central role within climate change observance, natural hazard management, environmental forecasting, food security planning, terrain mapping, and natural resources identification (Roberts et al., 2019, 2020). The commercialization of satellite Earth observation has expanded considerably in all sectors, with measurable growth realized in industries such as mining, energy, agriculture, and infrastructure monitoring. Estimates indicate that overall revenue from these services will grow from USD 1,5 billion nowadays to USD 2.4 billion by 2028 as the demand for higher-resolution images continues to grow (Crisp et al., 2020).

Satellites for remote sensing have been operated in a variety of orbits and orbital regimes each with distinct limitations and advantages. Geostationary Earth Orbit (GEO) provides broad coverage and real-time, continuous observation but with high latency due to its high altitude (Rani S et al., 2014). Medium Earth Orbit (MEO), used for navigation and communications satellite constellations offer global coverage but is less responsive to rapidly changing terrestrial conditions, and Low Earth Orbit (LEO), which is typically operated between 450 -2000km, provides satisfactory revisit frequencies, higher spatial resolution, and lower latency making it well suited for applications in Earth observation (Rani S et al., 2014). Growing need for ultra-high resolution, low latency, and near-real-time data has prompted the development of alternate orbital solutions such as the VLEO. An overview of the different characteristics per orbit is given in Table 1.

Very Low Earth Orbit (VLEO) has been defined as orbits between 180km and 450km (LaMarca, 2025). VLEO is an attractive option for remote sensing, as it provides solutions to challenges that currently limit higher altitude observation systems such as data handling inefficiencies, signal latency, and delayed target revisit period compared to LEO orbits (Abolghasemi Najafabadi and Kazemi, 2024). Furthermore, VLEO adds a crucial network layer to today's space architecture, supplementing the existing LEO, MEO, and GEO regimes. VLEO satellites, which are closer to Earth, improve the overall space-based network by enabling new modes of connectivity, such as direct satellite-to-ground links, satellite-to-satellite communications via inter-satellite links (ISLs) between spacecraft in the same and different orbital shells, and complete integration with the global ground station (GS) network layer which are vital for remote sensing and other space applications as illustrated in Figure 1 below.

In VLEO a wide range of applications can provide improved capacity for accurate sensing, particularly when combined with Synthetic Aperture Radar (SAR) systems or compact optical payloads. Such configurations enable significant improvement in environmental monitoring, precision agriculture, and disaster management. As shown in Figure 2, the addition of VLEO enriches the multilayered orbital ecosystem by enabling higher-resolution remote sensing, lower latency, and improved inter-orbital networking. However, compared to higher orbital regimes, VLEO necessitates a bigger constellation of satellites to obtain comparable coverage. We shall mention here as well a recent and promising proposal to use a SAR based constellation at 350km with considerable advantages described and discussed by the authors (Yang, 2025).

While the benefits of VLEO are tremendous, some challenges also counterbalance the benefits. Satellites are typically expected to be in orbits where the atmospheric density is very low. At VLEO, there is loading from a higher atmospheric density, which together with residual atmospheric drag and solar activity, limit mission life and require constant propulsion needs to sustain a very low Earth orbit. Recent studies have concentrated on orbital decay and de-orbiting operations, highlighting the increased interest in this field (Sannino, 2025). There are also challenges from a material degradation perspective, as the payload must maintain good protection from atomic oxygen. Adequate protective materials and coatings will therefore be required. Further to these problems, there are numerous operational and regulatory problems, including competing for spectrum, traffic management regulations, and policies not being developed yet (Sweeting, M., 2018).

This review is fundamentally framed around the question: how can VLEO satellite systems be sustainably embedded into the global space infrastructure to support, besides remote sensing, also communications, navigation, and Internet of Things (IoT) applications. It considers enabling technologies like hybrid propulsion, draft management, thermal control, and all the collaborative, regulatory, commercial, and governance processes. It is worth noting here that the increasing interest in VLEO related technologies led recently to a 2^nd symposium dedicated to VLEO missions, which took place at the University of Stuttgart in January 2025. The book of abstracts (University of Stuttgart, 2025) highlights the large number of planned VLEO projects and constellations worldwide, emphasizing mission and system design, specific propulsion concepts and VLEO specific orbital control aspects.

This paper is organized in the following way. Section 2 details the main technological and operational issues associated with VLEO constellations. Section 3 identifies new technologies that are intended to resolve these constraints. Section 4 considers various integration strategies to improve resilience and scalability. Section 5 reviews business models and dual use applications. Section 6 reviews collaboration and harmonization of policies. Section 7 discusses the findings and recommendations for further studies, concluding with a call for coordinated global action.

2. Navigating Technical Challenges in VLEO Satellite Constellations

VLEO satellite constellations offer unique opportunities for remote sensing, Earth observation, low-latency communications and IoT applications. Proximity to Earth provides great advantages for high-resolution imaging and quick revisit times, but it creates enormous technical challenges (Hild et al., 2022). This section assesses the physical, operational, and environmental challenges which must be solved to facilitate VLEO as a sustainable orbit for satellites.

VLEO satellites experience significant drag from the residual atmosphere, leading to not only accelerated orbital decay but also friction that acts in the opposite direction of the satellite’s speed as it orbits around the Earth (Crisp et al., 2020). This atmospheric drag is the main disturbance force acting on space objects in VLEO. The direction of the satellite’s motion is opposed by this non-conservative force. Equation (1) given below can be used to model the acceleration caused by drag, $a_{drag }\left({\mathrm{m}·\mathrm{s}}^{-2}\right)$ (Vallado, 2013).

Equation 1. Atmospheric drag acceleration acting on an Earth-orbiting spacecraft.

$$a_{drag}=-{\displaystyle \frac{1}{2}} C_D{\displaystyle \frac{A}{m}}\rho v_{rel}^2{\displaystyle \frac{v_{rel}}{\left|v_{rel}\right|}}$$

(1)

where the drag coefficient is denoted as $C_D \left(\mathrm{d}\mathrm{i}\mathrm{m}\mathrm{e}\mathrm{n}\mathrm{s}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{l}\mathrm{e}\mathrm{s}\mathrm{s}\right)$, the satellite’s cross-sectional surface area as $A \left({\mathrm{m}}^2\right)$, its mass by $m \left(\mathrm{k}\mathrm{g}\right)$, the atmospheric density at a specific height by $\rho \left({\mathrm{k}\mathrm{g}·\mathrm{m}}^{-2}\right)$, and the satellite’s velocity by $v_{rel} \left({\mathrm{m}·\mathrm{s}}^{-1}\right)$. There is still significant uncertainty in estimating atmospheric density. The atmospheric density is highly variable depending on the amount of solar and geomagnetic activity present. The variable density of the thermosphere, and therefore orbital lifetime, can vary significantly depending on solar cycles and diurnal architecture (Chen et al., 2023). Emmert (2015) demonstrated that the thermosphere density can vary multiple orders of magnitude vertically through only 100 km.

Another significant concern for VLEO is the presence of reactive atomic oxygen (AO). Atomic oxygen is present in VLEO and causes surface degradation to exposed spacecraft surfaces, as illustrated in Figure 3. Important materials such as those used in thermal coatings, optics, and power systems will be susceptible to erosion and contamination. Even the absorption of oxygen will change the physical properties of the materials and will lead to physical property changes in optical response, thermal response, and surface geometry. Pardini et al. (2010) also mention that these interactions will degrade the aerodynamic performance and mission reliability.

VLEO satellites experience extreme thermal cycling due to rapidly alternating sunlight and shadow. This has posed a unique thermal management challenge to thermal management and power generation systems because of the need to install both unique and passive radiators and active heating systems to stabilize board temperatures. There are serious challenges with the thermal management of satellites that remain in eclipse for extended period.

VLEO satellites experience short ‘sit-time’ over the ground stations due to rapid orbital motion. This places significant demands on ground segment infrastructure, which requires either a dense global network of ground stations and/or reliance on Inter-Satellite Links (ISL). Without the use of ISLs, VLEO satellites are likely to face latency and downlink capacity issues due to short visibility windows, which can impose a significant operational limitation (Luo et al., 2024).

Furthermore, aerodynamic torques due to differential drag and changing geometry will affect satellite attitude in VLEO. Earth observation missions with stringent pointing requirements necessitate a precise Attitude Determination and Control System (ADCS) to retrieve accurate data, and the situation is complicated by thermospheric winds, atmospheric co-rotation, and even the interactions with the Earth’s surface (Macario-Rojas et al, 2018). Cañas Muñoz et al. (2020) examined the effectiveness of passive aerodynamic control surfaces, particularly deployable fins, and body flaps, to generate torque in atmospheric flow to VLEO. These surfaces could enhance or partially substitute traditional attitude control methods (e.g., reaction wheels), especially on small satellites that have volume restrictions. The simulations indicate that there is a realistic reduction in power and momentum storage, which may help with compact and energy-efficient ADCS development.

Operational disadvantages of VLEO arise from an increased collision risk with debris and payloads due to close proximity orbits. VLEO altitudes are characterized by a self-cleaning activity (atmospheric drag) to a certain extent, but an increased launch activity leads to concerns about orbital congestion as there is no coordinated global traffic management system. A necessity exists to contribute to efficient conjunction assessment and automated collision avoidance (Rodriguez-Donaire et al., 2022). The complexity of technical issues presented alongside environmental risks makes it important to consider the interaction between drag, material breakdown, thermal loads, communication windows, and safety of orbit when designing a satellite to operate in the VLEO environment. The next section will review the latest technologies created to alleviate these concerns with the intent of maximizing the operational life of satellites in a VLEO environment.

3. Emerging Technologies in VLEO

Recent developments in spacecraft design, propulsion, communication, and thermal management systems focus on maximizing satellite lifetime and performance to reduce operational and environmental constraints in VLEO. The following sections summarize notable advancements in technologies reducing or allowing for increased drag-caused performance limits related to atmospheric drag, long-term degradation of materials, communication delay, and systems interoperability. Each of the solutions being developed contributes to a comprehensive solution that permits operation into a sustainable VLEO concept, avoiding orbital debris.

3.1. Aerodynamic Shaping and Drag Causing Performance Reduction

From the technologies proposed for sustainable operation in VLEO, aerodynamic shaping is perhaps the most important. Optimized surface geometries, e.g., shallow-angled surfaces and convex or rounded surfaces, simplify the flow of air around the object, reduce turbulence, and drag. Designs that include lift-producing shapes can increase orbit stability and maneuverability without full reliance on propulsion.

Uncertain or variable forward-facing geometries with deflective ability have been shown to significantly reduce drag based on recent studies and experimentation in wind tunnels. The DISCOVERER project validated the use of aerodynamic shaping to reduce the drag experienced on a satellite while continuing to accommodate attitude control. A graphical sketch of a slender design is illustrated in Figure 4.

3.2. Advanced Materials and Surface Engineering

In the effort to lessen atomic oxygen erosion, there is ongoing research in testing alternative materials such as coated composites, polyimide films, and erosion-resistant surfaces made from carbon. This research reveals that self-healing composites that restore surface integrity post-exposure may ultimately be a viable option. Wang et al. (2023) suggest the potential solution that an effective combination of geometry and new unique materials offers maximum durability and minimal degradation of performance. The goal is to improve and increase the structures or a structural and functional reliability in the face of the highly reactive dense VLEO atmosphere.

3.3. Hybrid Atmospheric Breathing Electric Propulsion (ABEP)

There are several hybrid propulsion systems under development to combine electric and chemical engines in order to manage orbit maintenance and maneuverability on demand. In the case of the VLEO orbit option, the Atmospheric Breathing Electric Propulsion (ABEP) has high potential for the VLEO area by harvesting residual atmospheric gases for in-situ propellants. Crisp et al., (2021) showed that, by implementing the ABEP systems, the overall fuel consumption and dependance on stored fuel was significantly less when compared to other propulsion systems, making them therefore very suitable for long-duration VLEO missions. Such ABEP systems, as schematically shown in Figure 5, provide sustainable drag compensation and provide the capacity of extending mission life without mass penalties.

An interesting application of ABEP propulsion is discussed by Yue et al (2023) proposing VLEO for elliptical orbits, reaching a perigee as low as 150 Km.

3.4. Thermal Control Systems

Due to the considerable frequency of eclipse periods and various temperature levels, a VLEO satellite will require various new thermal management systems. Active thermal control is generally comprised of heaters and heat pipes, and passive control relies on radiative coatings and phase-change-type materials. Abolghasemi Najafabadi and Kazemi (2024) discussed active and passive system integrations for temperature maintenance. These technologies are active components that help preserve survivability and continuous operation under high rates of temperatures in terms of heating and cooling.

3.5. High-Frequency Communication Equipment and Inter-Satellite Links

Like fifth generation (5G) IoT services, Ka-band Radio Frequency (RF) systems and optical laser communications are being explored to provide high throughput and low latency in the VLEO environment. Although optical systems can offer significantly higher bandwidth, they also face challenges such as line-of-sight stability and atmospherics interference. Moreover, Wu et al. (2024) investigate ISLs, which have the potential to provide uninterrupted data relay. They describe ISLs as a continuous communication mode which is particularly important for VLEO operations over oceans and remote regions, where ground stations are sparse.

3.6. Ground Segment Assimilations and Modularity

The ground segment will need to adapt to support future large-scale deployments of VLEO satellites. This includes modifying existing networks of ground stations and developing new ones that may incorporate Software-Defined Radios (SDRs) and phased-array antennas. Station automation can be designed to enable automatic handovers, frequency agility, data prioritization, and other advanced capabilities. Katona et al. (2020) proposed modular antenna systems with dynamic beam steering to enhance VLEO tracking and reception. Such flexibility will be important for all VLEO missions and constellations, improving overall reliability of service. If these emerging technologies are developed and deployed together, they could significantly enhance the feasibility of long-term, commercially viable, and operationally resilient VLEO constellations and services.

The next section will focus on how these emerging technologies cope with larger system-level approaches and sustainability frameworks for deployment on a large scale.