Author: Parikshit Padole

Satellites and Data Sovereignty: Who Owns Space Data?

1. Introduction
In an era where data forms the backbone of the modern world, satellites have become indispensable tools, collecting vast quantities of information from Earth’s surface every single day. From tracking climate change to monitoring deforestation, satellite data is critical for global governance, industry, and environmental stewardship.

Yet, as the use and demand for satellite remote sensing grows, so too do the complex legal and ethical questions surrounding the ownership and control of this data. As satellite technologies evolve and more data is captured from space, the gaps in international law regarding data sovereignty have become increasingly pronounced. The UN Remote Sensing Principles, adopted in 1986, attempted to address some of these concerns by regulating data access between states. However, these principles focus primarily on state interests, largely ignoring the privacy and ownership rights of individuals, corporations, and even the sensed states themselves.

Without modern, clear legal frameworks in place, we find ourselves navigating a rapidly changing space environment where access to data is determined more by economic power and technological capability than by principles of equity and fairness.

2. Gaps in International Space Law on Data Sovereignty
International Space Law provides a broader framework for the exploration and use of outer space but it does fall short while addressing the complex issue of data sovereignty, the big question who truly owns and controls the data collected by satellites? We might assume that the data is owned by the organisation that collects it, but no, it is not that simple or straightforward. In many cases, data protection laws mean that the people or entities whose data is being collected may have the ownership rights, even if they are not the ones to collect the data. Moreover, even when an organisation collects the data, it may not be able to fully extract its value so they collaborate and get involve with other organisations.

One of the key legal frameworks that attempted to regulate data collection from space is the UN Remote Sensing Principles adopted in 1986. The idea behind these principles was to create a balance between the sensing states(those operating satellites) and the sensed states(ones being observed). While these principles aimed to ensure non-discriminatory access to satellite data, they left many important questions unanswered. For example, the principles don’t really define who owns the data collected from a sensed state’s territory, nor do they provide clear ways to apply data-sharing agreements or protect the privacy of individuals and companies. The current international space law prioritises the freedom of sensing states to collect data while offering little protection to the privacy rights of the states being observed or their citizens. The idea that a country has the right to control information about its own resources or activities known as state privacy is noticeably missing from international treaties. This leaves states with limited options when it comes to pushing back against unwanted surveillance or data collection from space.

Also, the rise of private satellite operators has only made things more complicated. While the Outer Space Treaty places responsibility for space activities on states, including activities conducted by private companies, it doesn’t reflect today’s reality. Now, it’s private companies leading the charge in satellite data collection. This creates a legal grey area where private firms control vast amounts of data without any clear obligations to share it or safeguard the privacy of the sensed states.

3. The Role of Remote Sensing and Private Companies in Satellite Data
The advancement in remote sensing technology has been one of the most transformative
developments in space sector. Remote sensing allows satellites to gather detailed information about Earth’s surface without any physical contact. This data has become invaluable for a range of
applications, from environmental monitoring and disaster management to military surveillance and commercial ventures.

Today, private companies such as SpaceX and Planet Labs are at the forefront of satellite data collection, controlling vast amounts of critical information. These companies gather data that can be used for commercial purposes, sold to governments, or restricted entirely depending on their business models. This creates a legal grey area, where private companies are not always obligated to share data or ensure its fair distribution.

The rise of private satellite operators complicates the issue of data sovereignty further. In the past, satellite activities were primarily led by states, and international treaties were drafted with this in mind. Now, private entities dominate the scene, and many of the current regulations don’t account for their growing influence. This shift means that private companies can effectively monopolize access to satellite data, controlling not only who gets the data but also how it’s used. Without updated legal frameworks, there is a risk that data collected from space perhaps one of the most important resources of the 21st century could be controlled by a select few, leaving others, particularly developing nations, without equitable access to critical information.

4. Conclusion: The Need for Updated Legal Frameworks
As satellite technology continues to evolve and remote sensing becomes more advanced, the question of who owns space data has become one of the most pressing issues in international space law. Satellites are now capable of collecting vast amounts of detailed information from across the globe, and while this data is invaluable for a range of applications, from climate monitoring to urban development, it raises profound legal and ethical concerns about data sovereignty and privacy.

The current international legal framework, led by the Outer Space Treaty and the UN Remote Sensing Principles, provides only a partial answer to these challenges. These documents, while well intentioned, were drafted in an era when state-led space exploration was the norm. As a result, they leave critical gaps when it comes to regulating data collected by private companies, protecting the privacy rights of individuals and states, and ensuring fair access to satellite data.

To address these gaps, there is a clear and urgent need for updated international legal frameworks that not only define data ownership but also ensure equitable access to satellite data for all nations, safeguard privacy, and establish clear obligations for both states and private entities. As space becomes an increasingly commercialized domain, we must ensure that the benefits of satellite data are shared fairly, and that the principles of equity, transparency, and accountability are at the heart of the next generation of space law.

 

 

References

  • Butchard, P., & Mills, C. (2022, January 26). International Regulation of Space. commonslibrary.
  • Dunk, F. v. (2015, February 27). Chapter 9: Legal aspects of satellite remote sensing. elgaronline.
  • Leung, D., & Purdy, R. (2013). Outer Space Law Principles and Privacy. In F. G. Dunk, Evidence from Earth Observation Satellites: Emerging Legal Issues (pp. 243–258). Brill. [Retrieved from digitalcommons].
  • Martin, A.-S. (2020). The 1986 United Nations Principles on Remote Sensing Dealing with the Dual-Use Nature of Space Imagery. International Institute of Space Law, 18.
  • United Nations. (2017, May). V1605998-ENGLISH. unoosa.

Long-Term Orbital Perturbations of Satellites Due to Solar Radiation Pressure

CREDIT: NASA/Johns Hopkins APL/Ben Smith

Hello again! Welcome to the follow-up blog from the previous one where we discussed How Solar Radiation Pressure Affects Satellites: Calculating Instantaneous Force and Acceleration. As the title suggests, this time we’ll dive deeper into understanding how to calculate long-term orbital perturbations due to solar radiation pressure.

This is a vast topic, but my goal is to simplify it as much as possible for everyone. These blogs are aimed at providing a foundational introduction to the fascinating realm of orbital mechanics.

Now, I have a confession—if you’re a mathematician or physicist, can we have a video call? Sometimes I wonder if I should have pursued Astrophysics instead of diving into AI and Robotics. 😅 Just kidding! I’m much better in this field, and I can’t imagine myself knee-deep in equations with Einstein-style hair. At least, I like to think I’m cool… Please don’t get offended by my nerdy jokes!

Alright, enough yapping—let’s get back to the topic. To quickly recap what we discussed in the last blog:

Solar radiation pressure is the force exerted by photons emitted by the Sun when they strike a satellite’s surface. The magnitude of this pressure depends on:

  • The satellite’s cross-sectional area exposed to sunlight,
  • The reflectivity of its surfaces,
  • Its orientation relative to the Sun,
  • And its distance from the Sun (though for low Earth orbit, this is usually assumed constant).

While the force from solar radiation pressure is small, over time it can cause significant changes in a satellite’s orbital elements. In the last blog, we focused on calculating the immediate effect of this pressure, but not how it accumulates and affects the spacecraft over time.

This blog will cover exactly that.

To make it more realistic and understandable, we’ll use EIRSAT-1 as a case study—one of the most well-known student-led CubeSat missions, launched by the students of University College Dublin as part of the European Space Agency’s Fly Your Satellite! programme.

I didn’t find extensive details about the mission (Wikipedia had some info, but we all know how trustworthy that is), so I gathered what I could from official publications and real-time data from the n2yo website. As always, I’ll provide links below for anyone who wants to fact-check.

Now, let’s get all the information down properly and begin!

EIRSAT-1 Satellite Data
Latitude -41.18°
Longitude 74.18°
Altitude 481.19 km (299 mi)
Speed 7.62 km/s (4.73 mi/s)
Azimuth 232.0° SW
Elevation -55°
Right Ascension 07h 51m 50s
Declination -60° 20′ 10”
Launch Mass 2.305 kg
Dimensions 10.67 cm × 10.67 cm × 22.7 cm (4.20 in × 4.20 in × 8.94 in)
Satellite Period 94 minutes

 

Now we have the data let’s try to understand how and what steps are we going to take also before that let’s list down the factors to consider when calculating the effect of solar radiation pressure on an object:

Factors to Consider for Solar Radiation Pressure Calculations:

Orbital Elements:

  • Semi-major axis
  • Eccentricity
  • Inclination
  • Right Ascension of Ascending Node (RAAN)
  • Argument of Perigee
  • True Anomaly
  • Mean Anomaly
  • Eccentric Anomaly

Satellite Geometry:

  • Cross-sectional area
  • Reflectivity data

Material Properties:

  • Absorptivity and emissivity
  • Degradation rates over time

Orientation Data:

  • The satellite’s attitude and orientation over time

Distance to the Sun:

  • Updated regularly throughout the year to account for orbital variations

 

Step-by-Step Calculation

Solar Radiation Pressure Calculation

We already know the formula for calculating solar radiation pressure:

 

Determine the Cross-Sectional Area: Using the dimensions of

EIRSAT-1 (10.67 cm × 10.67 cm × 22.7 cm), the cross-sectional area facing the Sun (depending on its orientation) could be approximated. For the largest face:

 

Force on the Satellite Due to Solar Radiation Pressure

We’ll calculate the force exerted by solar radiation pressure using the following formula:

 

Instantaneous Acceleration on the Satellite Due to Solar Radiation Pressure

We can calculate the acceleration using Newton’s second law:

 

Atmospheric Drag Force Formula

FD is the drag force in Newtons,

CD is the drag coefficient (typically between 2.0 and 2.5 for satellites),

A is the cross-sectional area of the satellite (0.00024228 m2),

ρ is the atmospheric density at the satellite’s altitude,

v2 is the satellite’s velocity relative to the atmosphere (7.69 km/s).

 

Now we don’t know what is Atmospheric Density for that point of time so I used

NRLMSISE 2.0 is an empirical, global reference atmospheric model of the Earth from ground to space. It models the temperatures and densities of the atmosphere’s components.

Now we get,

 

let’s substitute it in the formula

 

Acceleration due to Drag

 

 

Now Finally,

Lagrange’s Planetary Equations:

You might wonder why we still need to use Lagrange’s planetary equations when we’ve already calculated the forces acting on the satellite. These equations allow us to determine how the orbital elements of a satellite (such as semi-major axis, eccentricity, inclination, and others) change over time due to external forces.

Since the focus of this blog is to calculate long-term orbital perturbations, Lagrange’s planetary equations provide a structured way to analyse the cumulative effects of small forces like solar radiation pressure (SRP) and atmospheric drag. They give us a clear picture of how a satellite’s orbit evolves over extended periods.

 

Above are the formulas for the  Lagrange’s Planetary Equations where

is the Semi-major Axis

is the Eccentricity

is the Inclination

ω̇ is the Argument of Perigee

Ω̇ is the Right Ascension of the Ascending Node

is the Time (Orbital Period)

I will be creating a separate blog dedicated to solving these equations in detail. If you have the necessary data for your own satellite, you’ll be able to input it into the equations and follow along to solve for long-term orbital changes.

Disclaimer: I am not a mathematician or physicist; the information presented here is sourced from various online references, which I have linked below. If you have any suggestions or feedback, feel free to reach out to me at ppadole@imperial.ac.uk 😊

References


General Perturbation Theory – Lagrange’s Planetary Equations, LibreTexts

Lagrange’s Planetary Equations, ASU Control Systems

EIRSAT-1 Conferences, EIRSAT-1 Official Website

Development, Description, and Validation of the Operations Manual for EIRSAT-1, Journal of Astronomical Telescopes, Instruments, and Systems

NRLMSIS Atmosphere Model

How Solar Radiation Pressure Affects Satellites: Calculating Instantaneous Force and Acceleration

CREDIT: ESA

First of all, hello again! Apologies for the long break—final year kept me busy, along with my part-time work, so I didn’t have much time to post. But now that things have settled down, I’m excited to start sharing the blogs I’ve been planning. I’ll be posting regularly, starting with today’s topic.
In this blog, we’ll dive into Solar Radiation Pressure and explore how it affects satellites.
Let’s begin!
In space, even the smallest forces can have significant effects on satellites over time. One of the key forces acting on a satellite is solar radiation pressure.

What is Solar Radiation Pressure?
Solar radiation pressure is the force exerted by photons from the Sun as they strike and reflect off the surface of a satellite. While seemingly insignificant, the pressure can considerably impact a satellite’s orbit, particularly its perigee height especially over long durations.

This force depends on:

  1. The satellite’s distance from the Sun.
  2. The satellite’s cross-sectional area facing the Sun.
  3. The reflective properties of the satellite’s surface

In the May 1960 paper, “The Influence of the Solar Radiation Pressure on the Motion of an Artificial Satellite,” researchers focused on the Vanguard I satellite, launched into Earth orbit on 17 March 1958. This satellite, intended for geodetic measurements, was designed with a diameter of 16.5 cm and a mass of 1.47 kg. Early orbit analyses of Vanguard I revealed unexpected discrepancies between the observed and predicted perigee heights.

The researchers explored solar radiation pressure as a potential cause for these deviations. Their investigation, using analytical methods to model the effects of solar radiation pressure on satellite orbits, indicated that this pressure significantly contributed to the observed perturbations in Vanguard I’s perigee height. This finding highlighted that even though solar radiation pressure is a relatively small force, it could cause substantial orbital deviations, particularly for satellites with a high area-to-mass ratio like Vanguard I.

So, how do we calculate solar radiation pressure and its effect on a satellite’s motion? Below, we’ll walk through the key steps and formulas that help determine the instantaneous force and acceleration on a satellite caused by this pressure.

Let’s break it down:

Step 1: Calculating Solar Radiation Pressure

Solar radiation pressure at Earth’s distance from the Sun is given by the following formula:

Solar radiation pressure at Earth's distance from the SunWhere

P is the solar radiation pressure.

L is the Sun’s luminosity (3.828 ×10^26 W) .

r is the distance from the Sun (Earth’s distance is 1.496 × 10^11 m )

c is the speed of light (3×10^8 m/s)

 

Substituting Earth’s distance into this equation gives us a solar radiation pressure at Earth:
P ≈4.56 × 10^(-6) N/m^2

This value will be used to calculate the force acting on a satellite.

 

Step 2: Calculating the Force on the Satellite

Once we know the solar radiation pressure, we can calculate the force on the satellite. The force depends on the satellite’s cross-sectional area (A) and its reflectivity(ρ). The formula for the force is:

Calculating the Force on the SatelliteWhere:

F is the force exerted on the satellite.

A is the satellite’s cross-sectional area in square meters.

ρ is the reflectivity coefficient (ranging from 0 for a perfectly absorbing surface to 1 for a perfectly reflective surface).

 

Example Calculation:

Let’s say a satellite has a cross-sectional area of 10 m² and reflects 30% of the radiation

(i.e ρ=0.3 ). The force acting on this satellite would be:

Example 1So, the instantaneous force acting on the satellite due to solar radiation pressure is F=5.928 ×10^(-4) N

 

Step 3: Calculating the Acceleration on the Satellite

Next, we calculate the acceleration on the satellite due to the solar radiation pressure. Acceleration is simply the force divided by the satellite’s mass ( ):

Calculating the Acceleration on the SatelliteWhere:

a is the acceleration

F is the force due to solar radiation pressure.

m is the mass of the satellite in kilograms.

Example Calculation:

For a satellite with a mass of 500 kg, the acceleration would be:

Example 2Although the force and acceleration caused by solar radiation pressure are small, they are persistent. Over time, they can lead to measurable changes in the satellite’s trajectory, especially for satellites with large area-to-mass ratios. For lightweight satellites, like CubeSats, solar radiation pressure can become a dominant factor affecting their orbits.

In terms of application this force can be utilised for example in solar sails the force from solar radiation pressure can be used  for propulsion, enabling satellites to move without fuel.

Conclusion

Solar radiation pressure, while small, exerts a continuous force on satellites. By calculating the instantaneous force and acceleration due to this pressure, we can understand how sunlight can gradually change a satellite’s orbit.

In future blogs, we will explore how this force can affect a satellite’s orbit over time, including resonant orbits and eccentricity changes

 

Disclaimer: I am not a mathematician or physicist; the information presented here is sourced from various online references, which I have linked below. If you have any suggestions or feedback, feel free to reach out to me at ppadole@imperial.ac.uk 😊

Source List 

Comet Tails and Solar Radiation Pressure

NASA’s Explanation of Sunlight Exerting Pressure

Luminosity from Britannica

Photon Mass and Physics

Scientific Article on Solar Radiation Pressure

NASA Technical Report on Solar Radiation

Solar Radiation Pressure in Engineering

NSSDC Spacecraft Data on Vanguard I

SRP Image ESA

A Big Hello to Everyone

Greetings to all my friends and colleagues at Imperial College London! Being a part of this amazing organisation has been a huge pleasure, and I am incredibly grateful to my hiring manager for giving me the opportunity to work here.

For those who don’t know me yet (and I’m quite confident that’s most of you), my name is Parikshit Padole. I’m a 19-year-old student currently pursuing a Bachelor of Science (Hons) in Computing Systems at Ulster University – London Branch Campus, and I’m now in my second year of study, I have a lot of things to share with all of you about my life and the fun things happening around me, but for now, I just wanted to say hello through this first blog post.

I’d also like to share that my passion lies in space exploration, and you can expect to see me posting a lot about that in the future, along with updates on my life in this gorgeous city of London. Thank you for reading, and I look forward to connecting with you all further!