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

Abstract

Very Low Earth Orbit (VLEO) satellites, operating at altitudes below 450 km, provide tremendous potential in the domain of remote sensing. Their proximity to Earth offers high resolution, low latency, and rapid revisit rates, allowing continuous monitoring of dynamic systems and real-time delivery of vertically integrated earth observation products. Nonetheless, the application of VLEO is not yet fully realized due to numerous complexities associated with VLEO satellite development, considering atmospheric drag, short satellite lifetimes, and social, political, and legal regulatory fragmentation. This paper reviews the recent technological developments supporting sustainable VLEO operations with regards to aerodynamic satellite design, atomic oxygen barriers, and atmospheric-breathing electric propulsion (ABEP). Furthermore, the paper provides an overview of the identification of regulatory and economic barriers that extort additional costs for VLEO ranging from frequency band allocation and space traffic management to life-cycle cost and uncertain commercial demand opportunities. Nevertheless, the commercial potential of VLEO operations is widely acknowledged, and estimated to lead to an economic turnover in the order of 1.5 B USD in the next decade. Learning from the literature and prominent past experiences such as the DISCOVERER and CORONA programs, the study identifies key gaps and proposes a roadmap to sustainable VLEO development. The proposed framework emphasizes modular and serviceable satellite platforms, hybrid propulsion systems, and globally harmonized governance in space. Ultimately, public–private partnerships and synergies across sectors will determine whether VLEO systems become part of the broader space infrastructure unlocking new capabilities for near-Earth services, environmental monitoring, and commercial innovation at the edge of space.

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 [1,2]. 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 [3].

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 [4]. Medium Earth Orbit (MEO), used for navigation and communications satellite constellations, offers global coverage but is less responsive to rapidly changing terrestrial conditions, and Low Earth Orbit (LEO), which is typically operated between 450–2000 km, provides satisfactory revisit frequencies, higher spatial resolution, and lower latency making it well suited for applications in Earth observation [4]. 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.

Table 1. Comparison of orbital parameters across different orbital regimes [3,4,5,6,7,8,9].

Parameter	VLEO	LEO	MEO	GEO
Altitude	~180–450 km	450–2000 km	2000–35,786 km	35,786 km
Orbital period	~88–93 min	~93–127 min	~2–24 h	~24 h
Orbital Velocity	~7.8–7.6 km/s	~7.6–6.9 km/s	~6.9–3.1 km/s	~3.1 km/s
Application	Earth observation, technology demonstration	Earth observation, communications, IoT, science	Navigation (e.g., GPS, Galileo, etc.), communications	Weather monitoring, TV broadcast, long range telecommunication
Mission Lifetime	days–several years (potentially up to 3–4 years without propulsion near 450 km)	~1–7 years	10–15 years	15 plus years
Orbital decay	High, due to atmospheric drag	Moderate	Low	Negligible
Launch cost	Low	Relatively low	Moderate	High
Two Way Communication latency	~1.2–3 ms	~3–13.3 ms	~13.3–238.7 ms	~238.7 ms
Coverage area	Narrow swath	Moderate	Wide	Covers ~1/3 of Earth’s surface
RF link-budget Efficiency	High (proximity to Earth)	High	Moderate	Low (requires powerful transmitters)

Very Low Earth Orbit (VLEO) has been defined as orbits between 180 km and 450 km [10]. 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 [11]. 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.

Figure 1. Remote-sensing orbit layers and data-relaying communication networks.

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 350 km with considerable advantages described and discussed by the authors [12].

Figure 2. Coverage comparison between VLEO, LEO, MEO, and GEO satellites.

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, limits mission life and requires constant propulsion 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 [13]. 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 [14].

While previous evaluations have mostly focused on spacecraft-level enabling technologies for VLEO operation, such as atmospheric drag effects, propulsion, and aerodynamic design [1,15], this paper takes a system-level and ecosystem-oriented viewpoint. In addition to enabling technologies such as hybrid propulsion, orbital control and maneuver, and thermal management, it specifically considers collaborative, regulatory, commercial, and governance processes that are crucial for the long-term integration and use of VLEO systems.

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 is worth noting here that the increasing interest in VLEO-related technologies led recently to a second symposium dedicated to VLEO missions, which took place at the University of Stuttgart in January 2025. The book of abstracts 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 [16].

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 describes the transfer from scientific and technological projects to commercial applications. Section 6 reviews business models and dual-use applications. Section 7 reviews collaboration and harmonization of policies. Section 8 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 [17]. This section assesses the physical, operational, and environmental challenges that must be solved to facilitate VLEO as a sustainable orbit for satellites.

VLEO satellites experience significant drag due to the presence of the residual atmosphere, which leads to accelerated orbital decay [1]. This atmospheric drag acts opposite to the satellites’ velocity and represents the dominant non-conservative disturbance force acting on the spacecraft in VLEO. Equation (1) given below can be used to model the acceleration caused by drag, $a_{drag }\left({\mathrm{m}\mathrm{·}\mathrm{s}}^{-2}\right)$ [6].

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

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

(1)

where the drag coefficient is denoted as $C_D \left(\mathrm{dimensionless}\right)$, 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 $\rho \left({\mathrm{k}\mathrm{g}·\mathrm{m}}^{-3}\right)$, 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 effects [18]. Also, it was demonstrated that the thermosphere density can vary multiple orders of magnitude vertically through only 100 km [19].

Another significant concern for VLEO is the presence of reactive atomic oxygen (AO) [20,21]. 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 [22,23]. 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 [21] These interactions will degrade the aerodynamic performance and mission reliability [24]. Atomic oxygen must be considered from the very start of VLEO spacecraft design, as evidenced by recent experiments. Surfaces’ aerodynamic characteristics alter as they gradually deteriorate, which has an impact on drag and could compromise long-term orbit stability [21,25]. For long-duration VLEO missions, this becomes especially significant. Surface erosion may drastically alter a spacecraft’s interactions with the environment over time, increasing drag and propulsion requirements throughout the duration of the mission [23,24].

Figure 3. Damage to an ISS solar array blanket box caused by atomic oxygen exposure (adapted from [26]).

In view of the importance of this risk for degradation and mission success, several solutions are presently investigated, including the chemical vapor deposition of multilayer protection barriers [27].

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. Based on more recent research, spacecraft in sub-Kármán-line (SKL) orbits, an extreme type of VLEO, are vulnerable to more rarefied atmospheric effects and dynamic drag perturbations, which elevate thermal cycling stresses and challenge the design of thermal control systems [28]. There are serious challenges with the thermal management of satellites that remain in eclipse for an extended period [5].

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) [29]. 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 [15,30].

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 [31]. The need for robust ADCS that will adjust to highly variable atmospheric environments is reinforced for considerations for SKL orbits, and these further demonstrate the way modifications in atmospheric column density and drag distribution near perigee can significantly alter orbital perturbations [28]. The effectiveness of passive aerodynamic control surfaces, particularly deployable fins and body flaps, to generate torque in atmospheric flow to VLEO has been examined. 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 [32]. Recent research stresses how crucial it is for ADCS design to take wind shear and diurnal atmospheric fluctuation into consideration, especially when functioning beneath 300 km altitude [21,33].

Furthermore, unless autonomous relay systems or predictive tracking are in place, high-frequency contact switching between VLEO satellites and ground assets enhances the chance of packet loss [29].

Significant progress is being made in this field by applying several modeling and simulation techniques. An example of this is the simulations proposed based on Monte Carlo techniques [33], and numerical modeling will undoubtedly benefit from the fundamental work undertaken under the ongoing ATLAS project [34].

Operational challenges in Very Low Earth Orbit (VLEO) arise from the combined effects of an expanding satellite population, limited global space traffic coordination, and the highly volatile orbital environment in VLEO orbit. Although atmospheric drag in VLEO provides a partial self-cleaning effect by speeding debris decay, increased launch activity and constellation deployment raise concerns about localized orbital congestion [35]. Higher orbital velocities, quickly changing orbital characteristics due to atmospheric drag, and shorter orbital lifetimes in VLEO might shorten conjunction warning times while complicating collision prediction and avoidance. Furthermore, detecting and categorizing items at extremely low altitudes remains difficult, which might raise operational danger. As a result, enhanced conjunction evaluation, tracking capabilities, and automated collision avoidance tactics are necessary to enable safe and sustainable VLEO operations [36].

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. Section 3 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 plays a key role in mitigating atmospheric drag. At VLEO altitudes, when the flow regime shifts from rarefied to transitional, optimal surface geometries such as shallow-angled, convex, or smoothly curved surfaces can minimize momentum exchange between atmospheric particles and the spacecraft, decreasing drag [25,37]. Aerodynamically shaped designs can also provide lift forces under certain attitude situations, resulting in greater orbit stability and limited mobility with less reliance on propulsion. Different geometric configurations, including active and passive aerodynamic control surfaces, have been therefore studied and suggested to compensate for this effect [32].

Recent numerical models and ground-based testing show that properly designed forward-facing shapes with regulated accommodation qualities may dramatically reduce drag while still meeting attitude determination and control requirements [5]. The DISruptive teChnOlogies for VERy low Earth oRbit (DISCOVERER) project evaluated the efficiency of aerodynamic shaping for drag reduction in VLEO, exhibiting both maintained attitude control and reduced aerodynamic resistance [5]. A graphical sketch of a slender design is illustrated in Figure 4.

Figure 4. Slender design preferred for VLEO (adapted from [5,38]).

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 [22,25]. This research reveals that self-healing composites that restore surface integrity post-exposure may ultimately be a viable option [21]. 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 [39]. The assumption that influencing surface chemistry along with macro-geometry is critical for minimizing AO erosion at orbital speeds is further supported by recent work [33]. Also, as ground-based simulations struggle to precisely simulate gas–surface interactions, experimental endeavors like Satellite for Orbital Aerodynamics Research (SOAR) stress the value of in-orbit validation of candidate coatings under practical VLEO scenarios [25].

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, Atmospheric Breathing Electric Propulsion (ABEP) has high potential for the VLEO area by harvesting residual atmospheric gases for in situ propellants. By implementing the ABEP systems, the overall fuel consumption and dependence on stored fuel were significantly less when compared to other propulsion systems, making them therefore very suitable for long-duration VLEO missions [5]. Such ABEP systems, as schematically shown in Figure 5, provide sustainable drag compensation and provide the capacity of extending mission life without mass penalties. In the VLEO setting, where extended exposure to atomic oxygen is a necessary operational requirement, the thermodynamic and aerodynamic characteristics of ABEP systems allow for persistent drag-compensated orbits [40]. When compared to conventional designs, the Front-Intake Solar Array Wing (FI-SAW), a novel intake design concept that integrates the atmospheric intake with the satellite’s solar arrays, may decrease required efficiency and specific impulse by up to 39% and 30%, respectively [41].

Figure 5. Visual representation of ABEP system (adapted from [3,38]).

ABEP performance is highly dependent on atmospheric density variability and inlet efficiency, both of which have a direct impact on mass flow rate as well as required electrical power [42].

A study on the CLEO platform reveals how modular ABEP satellite buses could successfully incorporate RF helicon-based inductive thrusters, producing a flight-ready system appropriate for activities at altitudes of 200–250 km [43].

An interesting application of ABEP propulsion is discussed, proposing VLEO for elliptical orbits, reaching a perigee as low as 150 km [44].

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. For VLEO missions to maintain temperatures, active and passive thermal management technologies must be integrated [11]. Spacecraft survival and continuous functioning under extreme heating and cooling cycles are directly impacted by these systems. Since heat flow and drag forces are often linked in VLEO, it has been emphasized that thermal management should be linked with aerodynamic surface behavior [33].

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 atmospheric interference. Moreover, inter-satellite links (ISLs) have been investigated for their potential to provide uninterrupted data relay. Researchers describe ISLs as a continuous communication mode that is particularly important for VLEO operations over oceans and remote regions, where ground stations are sparse [45]. Coupling ISLs with dynamic RF handover capabilities enables greater connection availability across a variety of orbital geometries [43]. ISLs are necessary for worldwide reach in under-connected zones and could decrease communication latency by more than 40% [29].

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. More automation must be implemented to manage the dynamic, resource-constrained nature of VLEO operations and to mitigate the short visibility windows encountered in these orbits, according to research on ground segment automation concepts for earlier and current VLEO satellite missions [46]. Modular antenna systems with dynamic beam steering have been proposed to enhance VLEO tracking and reception. Such flexibility will be important for all VLEO missions and constellations, improving the overall reliability of service [47]. 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 vital role of real-time ground segment reconfiguration for allowing limited but high-volume downlink sessions during each VLEO pass is further emphasized in recent work by [30]. Given the limited visibility windows common to VLEO missions, this is particularly significant [29].

It is important to note in this context that a present project, called Advancing Technologies of Very Low Altitude Satellites (ATLAS), is undertaking a systematic approach to VLEO-related technologies. The project is divided into three distinct subprojects, which are thematically grouped as follows [34]:

• Project A studies the gas–surface interactions. The objective is to gain fundamental understanding of, e.g., atomic oxygen, leading to numerical modeling of the VLEO environment;
• Project B concentrates on enabling subsystems, applying the scientific results to propose appropriate solutions for propulsion, power, and thermal control subsystems of VLEO spacecraft;
• Project C will then investigate mission-related challenges, covering scientific, data communication, and constellation operations.

Section 4 will focus on how these emerging technologies cope with larger system-level approaches and sustainability frameworks for deployment on a large scale.

4. Bridging Challenges in VLEO Satellite Constellations

The operational sustainability of VLEO satellites is based upon the ability to address existing challenges related to drag compensation, structural degradation, latency in communications, and space traffic management. More VLEO satellites will gradually become active, necessitating the ability to maintain efficient, dependable, and long-life operations. This section gives an overview of solutions that address technical and systemic challenges utilizing recent research and mission architecture.

4.1. Orbital Replacement and End-of-Life Considerations

VLEO satellites operating at extremely low altitudes (~180–250 km) generally endure orbital lifespans of days to a few months without propulsion, owing to significant atmospheric drag [48]. However, satellites functioning in the upper Very Low Earth Orbit (VLEO) zone (~250–450 km) can attain operational lifetimes varying from several months to several years, potentially up to 3–4 years at altitudes near 450 km, contingent upon the spacecraft’s ballistic coefficient and solar activity levels [3].

This means cost-effective, modular satellite platforms must be created that rely heavily on real-time tracking and automated end-of-life deorbiting actions as mandated by international agreements [49]. Reusable orbital transfer vehicle and in-orbit servicing platforms are considered as a method of prolonging mission life and the subsequent cost of replacement. These platforms must be robust and autonomous, taking into consideration the operational parameters for the VLEO environment.

4.2. Collision Risk Reduction and Space Debris

The operation of satellites in Very Low Earth Orbit (VLEO), close to the upper layers of Earth’s atmosphere, can increase the likelihood of collisions due to the growing number of satellites operating in overlapping altitude bands, rapid drag-induced orbital changes, and shortened conjunction warning times, and may contribute to future debris generation [50]. ADR systems capabilities (i.e., robotics collectors, drag-enhanced deorbit kits) are necessary to avert Kessler Syndrome-type scenarios in VLEO. Globally, regulatory compliance concerning passivation, deorbit timelines, and end-of-life disposal are at present inconsistent. A multilateral approach (i.e., UN COPUOS or IADC frameworks) leading to the harmonization of these provisions could alleviate orbital congestion [35].

4.3. Resilient Infrastructure and Satellite Hardening

VLEO satellites will need to consider survivability against rapid thermal cycling and the corrosive effects of atomic oxygen as part of their design. The implementation of smart coatings, shielding materials, and redundant electronics is altering survivability paradigms. In addition, autonomous health checking and self-healing materials are being investigated for a damage-tolerant approach [2]. This has the potential to increase both Mean Time Between Failure (MTBF) and mission uptime, especially for constellations servicing critical infrastructure, e.g., disaster response or secure financial communications.

4.4. Regulation, Coordination, and Interoperability

The deployment of VLEO systems in the international orbital traffic management systems will require addressing interoperability standards for satellite identification, licensing, and communications. Current policies consider LEO, MEO, and GEO while leaving a gap for VLEO-specific requirements [36]. The first steps towards developing registry and notification systems for satellite movements, similar to air traffic control systems, are underway. These will become important tools once the number of satellites in VLEO constellations increases in complexity and number.

4.5. Constellation Scalability and Finances

VLEO has an economic challenge to long-term viability. The high capital expenditure due to short operational life and launch frequency will challenge the economic business models. Any large-scale constellation of satellites is ideally established on economies of scale for manufacturing, flexible plugging and playing of systems, and government financing or commercial financing. There will likely be cooperation between private sectors, space agencies, and public actors (e.g., ESA’s Phantom, DARPA’s SabreSat) to develop partnerships that share infrastructure and risk. These business aspects have even led some analysts to label VLEO as the next (commercial) Frontier in orbit [51]. Overall, the solutions above outline a path forward to a sustainable VLEO architecture that provides high-throughput, low-latency services. In Section 5, we emphasize the business aspects.

5. Transition of VLEO Applications from Science to Business

First interest in the VLEO environment was purely scientific. As an example, we can refer to studies on the behavior of early near-earth satellites and the observed effects of drag (interesting enough, these satellites were referred to with their scientific names such as 1957β, 1958δ₁ and1958δ₂ instead of the Sputnik [52]. Emphasis was placed on better knowledge of the atmosphere and geomagnetic fields in that layer. Later, the obvious advantages of higher resolution earth observations raised increasing interest, with the first space-based reconnaissance programs using VLEO such as CORONA. Development of this program started in 1957, leading to the development of dedicated cameras for this purpose. After some failures, the first successful VLEO observation flight took place on 10 August 1960 [53]. The series of satellites were labeled as Key-Hole (KH), whereas the scientific aspect was referred to by different names for the same type of satellites.

Technical details on this program reveal that the platform used was in fact the upper stage of a THOR rocket, called Agena. The initial cameras were especially developed with an f/5.0 aperture and a 61 cm focal length, which was quite advanced at that time and allowed for a resolution of 7.5 m. The satellites operated at a height of less than 150 km and evidently, the cameras were constantly improved over the succeeding 12 years of operations, eventually reaching a resolution better than 1.5 m [54].

It is important to mention here that the recent interest from, e.g., DARPA in VLEO still illustrates the high interest and potential for developing and testing air-breathing platforms with novel electrical propulsion and with a dedicated platform under development, labeled SabreSat [55]. Also, CASIC, a Chinese space contractor, is reported to have a VLEO-dedicated operational launch site ready for orbits between 150–300 km [56]. In addition to this, EDA has also started activities in this field. An interesting EDA project is LEO2VLEO, allowing a LEO satellite to be put in VLEO in case of need, but to be maneuvered back to LEO to extend its lifetime [57]. This concept has been discussed in the framework of the so-called V-LEOS approach. In this hybrid scenario, the satellite in LEO would descend to VLEO, either at its end-of-life or on request of the customer, for a short period of enhanced performance before re-entry [58].

Evidently, these positive experiences triggered scientific and civil interest, initially in the field of Earth Observation but gradually also in other space domains. Examples are the European Phantom platform (see Figure 6), presently commissioned by ESA, the European Space Agency, as well as previous scientific missions such as INSPIRESAT, performing measurements of drag effects, ionospheric measurements, and effects of atomic oxygen [59]. We shall also mention here the scientific GOCE mission (Gravity field and Steady-State Ocean Circulation Explorer) launched in 2013, which operated down to 229 km altitude to gain considerably increased knowledge of the Earth’s gravity field and provided important results on the Earth’s magnetic field [60].

Figure 6. Artist’s impression of Redwire’s Phantom European VLEO Platform (Redwire, Europe).

From a technology demonstration perspective, an important milestone to be mentioned is the Japanese Super Low Altitude Test Satellite (SLATS), which was launched in 2017 and operated for 111 days in VLEO. This multipurpose satellite demonstrated several key technologies in VLEO, such as orbital control features, but also scientifically measured several VLEO environmental parameters, enhancing the necessary knowledge for later operational satellites [61].

Beyond the scientific interests related to atmospheric physics and space weather, operating in lower orbits naturally opens the door to a wide range of commercial opportunities:

• Remote sensing: being closer to the Earth’s surface significantly improves spatial resolution, enabling unprecedented detail for applications such as urban planning, precision agriculture, environmental monitoring, and disaster assessment;
• Telecommunications: shorter signal paths through the atmosphere reduce signal loss and latency, which is critical for real-time transactions, emergency response services, and high-speed data links. This also enables improved communication in challenging environments such as tunnels, mines, or dense urban areas.
• But we should also not ignore other potential applications, such as:
• Navigation and positioning: lower-orbit systems can enhance the accuracy and reliability of geolocation services, benefiting everything from autonomous vehicles to surveying and location-based services;
• Emerging applications: a range of innovative uses is currently in early academic exploration. As new constellations become operational, entirely new markets and technologies will inevitably emerge, driven by the unique advantages of low-orbit infrastructure.

At the same time, from a business perspective, several equipment costs can be reduced as well as other cost savings.

• As far as the ground segment is concerned, smaller antennas can be used on Earth;
• Reduced radiation can lead to the use of cheaper satellite components;
• The launch cost can be reduced either by using adapted launchers (e.g., two stages only) or less propellant.

As far as launch costs are concerned, an analysis of the different launcher options is evaluated in a trade-off study, which concludes that the new generation of small launchers under development is the best alternative for placing satellites in a VLEO orbit [62]. It is interesting to mention here the first patent that was initially filed in 2016 by Dr. Reedy, founder of Skeyeon, a company that is still having a leading role in VLEO applications. The patent is simply called ‘Satellite Systems’ and we can quote from the summary of the patent application [63]: “A satellite system operates at altitudes between 100 and 350 km relying on vehicles including a self—sustaining ion engine to counteract atmospheric drag to maintain near-constant orbit dynamics. The system operates at altitudes that are substantially lower than traditional satellites, reducing the size, weight, and cost of the vehicles and their constituent subsystems, such as optical imagers, radars, and radio links. The system can include a large number of lower-cost, mass, and altitude vehicles, enabling revisit times substantially shorter than previous satellite systems. The vehicles spend their orbit at low altitude, high atmospheric density conditions that have heretofore been virtually impossible to consider for stable orbits. Short revisit times at low altitudes enable near-real-time imaging at high resolution and low cost. At such altitudes, the system has no impact on space junk issues of traditional LEO orbits and is self—cleaning in that space junk or disabled craft will de-orbit” (Source: [63]).

The patent, therefore, can be considered to have opened the way for the commercial use of VLEO by stressing the cost-saving potential. Equally interesting was the visionary introduction of the ‘self-cleaning’ environmental aspect, which was later taken over by authors discussing this impact [35].

In line with this, in the next chapter, we will focus on the business aspects of VLEO applications whereby clear emphasis will be put on civil applications. It is rather obvious that the higher resolution from VLEO satellites leads to an interest in military and dual-use applications [64]. However, this is considered as a different topic and, although it no doubt will considerably influence business-related aspects such as turnover, this is not considered within the scope of this article.

6. Business and the Very Low Earth Orbit Industry

The progression of VLEO satellites, from ocular reconnaissance instruments for securing defense applications and scientific near-earth observations, to commercial space vehicles, is leading to an obvious economic potential. Interest, both from public and private stakeholders, has emerged across many sectors of VLEO, including Earth Observation, telecommunications, and in-orbit manufacturing. This section focuses on civil services and business opportunities of VLEO.

In a study comparing the different VLEO applications in terms of business potential [65], different VLEO applications were evaluated in terms of business potential (see Table 2).

Table 2. Potential VLEO applications and business success evaluation (adapted from [65]).

Potential VLEO Applications

Criteria for Business Success

Earth Observation (EO) optical systems; Mobile high speed; Light Detection and Radar (LiDAR); High-speed internet access through terminals; IoT critical type communication; Passive infrared and radar; Real-aperture radar; Quantum key distribution; Coverage extension for aeronautical services; Underground communications; Smart data relays; Store and forward (non-real time connectivity); High-precision positioning and navigation.

Market size; TRL; Potential growth; Competition; Cost of production; VLEO suitability; Complexity; Regulation.

Using weighting factors for the different criteria represented in Table 2, the study [65] concludes that the most probable areas for VLEO business are:

• Remote-sensing optical systems;
• SAR (see also [12]);
• Mobile high-speed internet access (see [66]);
• LiDAR (see also [67]);
• High-speed internet access through terminals.

It is therefore no surprise that several supporting technological programs are initiated, such as the European Commission DISCOVERER program and the DARPA OTTER program, to provide research knowledge for companies working in the field of VLEO. At the same time companies such as Thales Alenia Space, Redwire, Albedo, Earth Observer, Orbion Space Technologies, Viridian, Kreios Space, and Deepsat, just to name a few, are actively involved in VLEO applications and resulting business opportunities [68]. This wide range of potential applications and opinions brings us to the quasi-impossibility of predicting the market for VLEO applications, as many potential applications are still at a feasibility stage. We can illustrate this here by a number of aspects being studied as potential applications and studied amongst others at UPC, such as those referred to in the research overview [69]:

• Pest warning for agriculture;
• Sustainable management of urban growth;
• Optimal routing for fishing vessels;
• Measuring buildings’ energy efficiency.

Several business cases on VLEO applications have been developed in recent years. In order to illustrate the wide range of potential applications, we can refer here to business models for VLEO constellations [70], a business approach for tracking vessels [71], and, obviously, a business canvas approach applied to Earth Observation business in VLEO [72]. Economically, an important aspect is the value of these potential applications in financial terms.

As a benchmark, we can refer to a recent forecast report [73], which analyzed data from 2019 to 2024 in the field of VLEO and examined the competitive landscape and growth potential. The global VLEO market in 2024 is estimated in the report to be 7.59 million USD and expected to grow by 2030 to 1.48 B USD (which represents an important CAGR (Compound Annual Growth Rate) of more than 140%). Another forecast report [74] estimates the growth for the same period (2024–2030) at 66%. A recent market study considers the market growth in the period 2025–2034, forecasting a CAGR of 74%, and forecasting the market to reach a turnover of 1.5 B USD by 2034 [75]. Note that this report also lists the main actors in the VLEO business, which are in their own assessment, Sierra Space, Eutelsat, Albedo, Thales Alenia, Redwire, Leo Labs, Earth Observant, and CASIC. It looks, therefore, that there is no doubt that VLEO will become an important market, depending on the assumptions, of at least 1 billion USD in the next decade.

Although these growth forecasts may look very optimistic, we shall consider that the figures are largely based upon new telecommunication applications, evidently the largest market in the present space economy. In order to illustrate this, besides the obvious remote-sensing potential, which will undoubtedly be the main VLEO driver, a number of potential telecommunication applications and their VLEO advantages are described in detail in a study [66] and can be summarized as per Table 3.

Table 3. Potential VLEO telecommunication applications and benefits (adapted from [66]).

Telecommunication Application	VLEO Benefit
Underground Communications	Low-frequency communications
High-speed Internet access for mobile applications	Latency reduction
Direct-to-handheld broadband communications	Better link budget
Store and forward data transmissions	High data rates thanks to better link budgets
Critical and cyber secure transmissions	Low latency
Quantum Key Distribution (QKD)	Low range and smaller areas
Aeronautical communications	Smaller areas reduce interference

To put this VLEO growth potential in an economic context:

• The World Economic Forum estimates that the space turnover will be over 1000 B USD in 2030 (considering a new calculation approach proposed by McKinsey) [76];
• This would result in a space application market in the range of 250–300 B USD in 2030.

The aforementioned 1.5 B USD of new VLEO business in the next decade is therefore surely feasible within this >250 B USD space applications envelope and illustrates that VLEO operations represent a very viable business case for the coming five years. In order to stress this point, we can also mention that recently equity investors have shown a growing interest in this emerging VLEO market. To illustrate this, hedge funds are already suggesting risk investments in promising start-ups in the VLEO market and even provide a list of the, in their opinion, most promising startups [77].

We shall recall here that key factors enabling VLEO business scalability include:

• Use of smaller antennas on Earth (due to reduced slant range);
• Commercial Off-The-Shelf Components (COTS) components (less radiation exposure and thus potentially cheaper);
• Rapidly lowering cost of launch (two-stage launchers, air-breathing).

Simultaneously, the ultimate and financial success of the VLEO business activity will depend on the risks associated with uncertainty in the policy environment, lifecycle management approaches, and possible mutual dual-use agreement for components that will reduce capital risk and duplication of new infrastructure.

In conclusion, VLEO has emerged from surveillance technology but is now developing into a new frontier of business innovation. This transfer is driven by its unique orbital physics operating environment, technology momentum, and increasing demands to deploy similar systems from the existing substantial use cases from EO and telecom. The next chapter discusses how international policies, governance, and harmonization for the domain can facilitate integrating VLEO into this ecosystem and scaling some of these new risks and ambiguities.

7. Governance, Regulation, and Policy Harmonization

For the sustainable development of VLEO satellite constellations, technical development and commercial sustainability are insufficient; appropriate international regulations are required as well. In order to prevent fragmentation and guarantee fair access for operators, coordination is necessary to address the jurisdictional governance concerns posed by spectrum rights, STM, and debris management.

7.1. Fragmentation

The space policy framework that we currently have mainly only focuses on the issues related to orbits at higher altitudes (LEO, MEO, and GEO) and fails to address VLEO-related requirements. License inconsistencies, redundant procedures, and ambiguity pose substantial hurdles for an operator who would want to coordinate licenses across multiple jurisdictions. Operators face the greatest hurdles in VLEO spectrum allocations due to the continuation of conservative processes and frequency competition in the proper allocation. In addition to being time-consuming, the ITU’s own allocation mechanism does not meet the low-latency standards for VLEO networks.

Laws and regulations have struggled to keep pace with rapid technological advances in VLEO. As a result, gaps have emerged in how these activities are governed. On the other hand, the legal and administrative frameworks designed to govern VLEO tend to take considerably more time to develop. The disparity results in uncertainty and oversight issues for both businesses and politicians. It also serves as an example of the “pacing problem,” a well-known issue with changing technology governance that arises when innovation advances more quickly than legal and policy frameworks can keep up [78,79].

However, as mentioned in Section 5 [3], many future operational and commercial applications of VLEO are still unknown, making it challenging to create laws that are both suitable and effective. Regulations that are introduced too soon or in too general terms run the risk of being unduly restrictive and may deter investment, innovation, and the creation of workable business models. However, continuing to rely on regulatory frameworks created for other orbital regimes without modifying them to the particular circumstances of VLEO can lead to coordination issues, raise safety concerns, and raise long-term issues for orbital sustainability and space traffic management [80,81].

7.2. Shortcomings of STM

As VLEO activities increase, there will be increasing risks associated with congestion and possible collisions in various close orbits. As approaches for coordination, countries may rely only upon national-level tracking assets (e.g., the US Space Surveillance Network) and have protocols for voluntary coordination. At present, these provisions typically involve ground-based sensing, periodic orbit determination updates, and batch-style conjunction screening, with information exchange occurring on timescales of hours to days rather than in near real time. Through developing harmonized, near-real-time STM, both commercial and global, and including new and emerging space jurisdiction, these risks need to be mitigated, in analogy with present civil aviation air traffic control procedures.

However, such existing provisions are not suitably adapted to VLEO operations because strong and variable atmospheric drag causes rapid orbital changes, increasing prediction uncertainty and significantly shortening conjunction warning times. As a result, the current STM framework does not provide the low-latency, end-to-end capabilities, from sensing and orbit determination to notification, coordination, and maneuver execution required for time-critical collision avoidance in VLEO. Standardized protocols for maneuver notifications, a protocol for interpretational tracking, and legally binding commitments for collision avoidance will have to be put in place. It is suggested that these efforts should be supported by the implementation of modern tools such as Artificial Intelligence for Collision Avoidance [82].

7.3. Debris Mitigation and End-of-Life Standards

VLEO satellites’ density and size may lead to increased debris rates even though they will usually deorbit more quickly than their higher-orbit counterparts. There is uncertainty over accountability and cleanup responsibilities due to the lack of legally mandated deorbiting and passivation requirements. For the deorbiting of space debris, organizations such as the Inter-Agency Space Debris Coordination Committee (IADC) have proposed voluntary recommendations. This must be established inside a legally enforceable framework, nevertheless. Codes of national space laws could be developed that require the operator to abide by end-of-life disposal standards, with considerations for deorbit deceleration design standards. A detailed analysis of legal and policy implications of VLEO operations concluded that there are no basic obstacles from this perspective, in relation to present treaties and regulations, although careful monitoring and possible refinements would have to be considered [83].

7.4. Gaps Related to Liability, Risk, and Insurance

Liability for satellite failures, damage to third-party property, and collisions remains ambiguously defined. The Outer Space Treaty and the Liability Convention provide general norms for actors in space; however, practical mechanisms for liability are limited. Operators face difficulty in obtaining adequate coverage and premiums because of underdefined liability allocation and risk-sharing arrangements. The development of multilateral insurance pools could be market-driven with flexible liability coverage and lower premiums, leading to greater economic stability. From a legal perspective, though, it has been pointed out that the lack of an agreed definition of the VLEO orbits and, therefore, the distinction between LEO and VLEO might lead to discussions when applying the Liability Convention and insurance disputes [83].

7.5. Geopolitical and Export Restrictions

Export control mechanisms such as the International Traffic in Arms Regulations (ITAR) in the US and equivalent national export control regimes constrain cross-border technology sharing and create complications for satellite launches. Export regulations may lead to delays in VLEO deployments or, at a minimum, inhibit international partnerships, especially when determining the use of dual-use items [84,85]). Global space governance organizations need to find ways to create frameworks that still allow for national interests while realizing the benefits of joint international collaborations. Open standards for data formats, platform interoperability, and shared STM platforms can foster confidence regardless of the discussions [86,87].

7.6. The Path Towards an Integrative Global Framework

To achieve full VLEO integration in a sustainable way, international space law needs to evolve to include governance instruments specifically for VLEO [88,89]. Potential solutions could include:

• An international VLEO mission registry [80];
• Allocated frequency for ultra-low-latency constellations [90];
• Legally binding debris remediation protocols [91,92];
• Access protocols for shared low-altitude corridors [80];
• An appropriate governance structure [89].

For the creation of legally enforceable but adaptable policy frameworks that allow responsible operations in VLEO, organizations like UNOOSA, ITU, IADC, and regional space consortia must work together [88]. Due to delays, disconnected compliance regimes, commercial uncertainty, and heightened orbital hazards, VLEO development could run into significant difficulties in the absence of updated regulatory backing [92]. Thus, guaranteeing responsible long-term stewardship of this crucial orbital zone and realizing the full potential of VLEO commercialization depend heavily on international policy harmonization.

As far as the latter aspect is concerned, several authors have pointed out the relation between VLEO and sustainability. In particular the self-cleaning nature of VLEO and therefore the impact on space debris has been brought forward as a positive aspect of VLEO use [35]. Combined with potentially reduced launch costs, this could become an important sustainable element of the future circular economy of space, as proposed by ESA in a White Paper [93].

8. Discussion and Suggestions for Further Work

This research identifies and consolidates an extensive range of technological, regulatory, commercial, and operational solutions required for the VLEO satellite systems to be accepted in the broader space ecosystem. The study has the following major findings and recommendations:

• There is potential for significant drag reduction, and therefore lifetime enhancement, by utilizing improved materials, such as atomic oxygen-resistant coatings and self-healing composites, and utilizing shape to achieve aerodynamic form. While wind tunnel testing and computational fluid dynamics data suggest actual improvements were observed, studies are still needed to assess durability in the VLEO environment;
• Development of hybrid propulsion architectures, such as ABEP, will allow the capability to sustain altitude with lighter and more sustainable systems, which require less onboard propellants. These systems collectively offer a scalable approach to cost-effective and long-term VLEO operations;
• It is critical to scale ground capability to maintain real-time contact with VLEO satellites. Wide-scale adoption of SDRs, phased-array antennas, and ISLs should be employed to maintain continuous connectivity, increase data throughput, and expand the effective data reach of ground stations;
• It will require internationally collaborative efforts to harmonize regulations for spectrum assignments, on-orbit congestion management, and STM, and to adopt updated legal instruments that will help classify the liability regime and mandate deorbiting plans;
• Public–private partnerships (PPPs) will play a key role in funding infrastructures, launching constellations, and de-risking research and development for long-term sustainability, in addition to using modular satellite designs that can allow for more flexibility on multiple mission profiles;
• It will be important to institutionalize active debris-removal systems and plans for decommission. Technological solutions, such as in-orbit servicing, robotic repairs, and recycling systems, will aim to improve the efficiency of spacecraft lifecycles. Although considerable progress in this field is documented [94], further studies and trade-offs are needed in view of limited lifetimes for the servicing vehicles in VLEO;
• The market potential for VLEO applications is considerable. From a remote-sensing point of view, the enhanced resolution will be driven initially by dual-use applications and then gradually transferred to civil applications. In addition to this, a number of promising telecommunication applications will create additional markets.

These are not just isolated technical issues to solve but interconnected solutions that need to be executed. Each part fits into a comprehensive architecture that will allow for VLEO missions to operate alongside their support of remote sensing, communications, navigation, and new commercial derivatives.

9. Conclusions

VLEO satellites may represent a paradigm shift to next-generation space infrastructure. Their proximity to Earth allows operational strategies based on very low orbital altitudes, providing higher image resolution, ultra-low-latency communications, and better revisit rates that are necessary for real-time applications like remote sensing, disaster response, and secure communications [31,46]. However, realizing these benefits is challenged by significant barriers such as high atmospheric drag, limited operational lifetime, and a fragmented regulatory landscape [5,81]. This study indicates that several newly developed material science, propulsion, thermal control, and ground communication technologies can overcome those challenges [12,23,34,48].

The business case for VLEO systems is compelling, particularly with telecommunications, and scientific payloads, besides remote-sensing dual-use missions. Indeed, several predictions foresee a VLEO market potential of some 1.5 B USD in the next decade. The industry forecasts exponential market growth if standardized governance, scalable infrastructure, and coordinated international policies are developed and implemented. Moving forward, VLEO systems must not be considered as a stand-alone project but, rather, as a strategic component of a global space infrastructure. Coordinated activities between academia, government, business, and multilateral institutions will be required. If undertaken responsibly, with elements of sustainability and equitable policy and approaches, VLEO satellites can serve as the dependable workhorses of the 21st century orbital economy at low, near-Earth altitude.

It is of paramount importance to stress that the current research is limited to the academic fields of aerospace engineering, commercial space studies, remote sensing, and space policy. The findings are intended for beneficial remote-sensing applications, such as urban planning, disaster monitoring, climate monitoring, smart agriculture, and industry innovation, and do not pose a threat to public health or national security.

The authors acknowledge the dual-use potential of research involving satellite technologies and remote-sensing capabilities and confirm that all necessary precautions have been taken to prevent potential misuse. All information presented is derived from the open-source, publicly accessible literature, and no sensitive technical details, classified data, or operational methods are disclosed.

As an ethical responsibility, the authors strictly adhere to all relevant national and international laws and guidelines concerning Dual-Use Research of Concern (DURC), export control regulations, and space technology governance. The authors advocate for responsible deployment, ethical considerations, regulatory compliance, and transparent reporting to mitigate misuse risks and foster beneficial scientific and societal outcomes.