Conjunctions in the RF Spectrum: Results from an RF Measurement Campaign of LEO Objects
The Radio Frequencies (RF) Spectrum is, on the one hand, an important factor of successful satellite operations and satellite-based services, but on the other hand, it is a limited natural resource. The increased commercial activities, especially in LEO orbits have a direct impact on the availability of satellite services, the safety of operations and the ‘dark and quiet skies’ topics.
Classical carrier monitoring systems from established providers were developed mainly to monitor GEO objects. They are working in a round-robin cycle to record RF measurements, also mainly applying highly sufficient signal intelligence. However, this approach lacks systematic measurements in correlation with LEO objects.
To overcome this hurdle, Space Analyses has developed a new three-dimensional object measurement system (THRIMOS) with the help of ESA funding in the ARTES program line. This new system was used to perform a measurement campaign in October and November 2024 to seek answers to the question if any evidence of interference can be found between two large satellite constellations in the downlink payload traffic. If yes, how big the impact on the availability would be.
Until end of November 2024, more than 7200 measurements were taken. These measurements were able to confirm the interference between the two satellite constellations. Based on the counts of recorded interference events, it was possible to estimate availability figures.
The results showed a significant impact in the service availability of at least one constellation. The resulting figures of the estimated user service availability were less than 99.5%.
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Please note that some dates and locations has anonymized, never the less the recorded data are based on real data
Long-Term Data Analysis for Improved Risk Assessment regarding Orbital Assets
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09/03/21: Proposal to use UN-SPIDER Sendai Framework as methodology to
implement Space Traffic Management
The paper proposes the UN-SPIDER Sendai Framework as methodology for the implementation of the
wide meaning of Space Traffic Management (STM) as contribution to the preparation of international
space traffic and space environment management rules and efforts. This paper includes an assessment of
the readiness in disaster risk management based on the vulnerability of the space environment including
resulting consequences on the socio-economic life on Earth. The paper also shows a risk pattern as
proposed in the Sendai Framework
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A systems theory approach for evaluating the cascading collision potential of orbital shells
© 2022 Advanced Maui Optical and Space Surveillance Technologies Conference (AMOS)
Valentin Eder
Christian Unfried
link to download the paper: https://amostech.com/TechnicalPapers/2022/Poster/Eder.pdf
ABSTRACT
Understanding the probability and the impact of cascading collisions in earth’s orbit turns out to be one of the more
controversial topics in space sustainability and risk management. A lot of work invested over the past decades and
especially in the last years has led to a better understanding of fragmentation and collision processes [1][2]. The
fragmentations and collisions which took place during that time served as real-life examples to validate or falsify
model approaches, and to refine them. So far, we have not seen cascading collisions leading to what has been
described as the “Kessler syndrome” decades ago [3][4]. Similar to climate change, it is not possible to determine
exactly when the tipping point will be reached, but we know we are moving closer to it every day.
Using a systems theory approach, the goal of our research was to enable a perspective which is not meant to be
contrary, but rather complementary to existing astrophysics and astrodynamics approaches which mostly care about
conjunctions and collisions as risks for single objects, their dynamics and interaction with other single-object items.
We show how we can learn from available data and its correlations rather than feeding Monte-Carlo method results
into theoretical models. We show how we can use traffic lane analogies from a system traffic point-of-view rather
than from a moving-object perspective only. We show how understanding impacts of internal and external changes
to orbital shell systems can provide added value for decision-makers that designing better-than-required criteria as
thresholds for space sustainability awards on a per-object basis cannot yield.
We use existing measurement data, collected and assigned to altitude- and time-based systems of space objects, for
analyzing the interactions of space objects and their evolution over time. This leads us to parameters describing the
risk and the potential of cascading collisions. Other than the collision risk obtained by traditional astrophysics and
astrodynamics methods [5][6], this cascading potential does not tell something about single object risks, but says
something about the overall system, about the likelihood an “infected” object can “infect” further objects. Such
potential analyses can be performed for different orbital shells and object types with the cascading potential change
over time allowing an interpretation of the past, of the current situation and for future scenarios.
We show that for the calculation of the cascading potential, there is a difference between an object repeatedly
meeting the same other object, and an object meeting many different other objects on its daily journey. Like in
epidemiology, the risk of spreading an infection in a population is much bigger if there is a bigger exchange between
many. (Note that this is different from the other perspective of the individual risk of getting infected [7][8].)
The resulting parameters and their variation over altitude and time can be used to identify trends, to assign priorities
and, therefore, to support decisions e.g., in Active Debris Removal (ADR) planning, but also for life-time extension
and Post-Mission Disposal (PMD) considerations [9]. All of these are important tasks on the way to a sustainable
use of outer space by our and future generations, which is the guiding vision to which we dedicate our efforts