Airspace closures due to reentering space objects


Assessing impact of space launch and reentry operations on the national airspace system (NAS) using historical traffic patterns

A. Srivastava
T. J. St. Clair
S. Zobell
D. Fulmer

Symposium on Dependable, Autonomic and Secure Computing (DASC)


Sharing airspace: Simulation of commercial space horizontal launch impacts on airlines and finding solutions

J. K. Tinoco
C. Yu
R. Firmo
C. A. Castro
M. Moallemi
R. J. Babb


Effects of Future Launch and Reentry Operations on the National Airspace System


ATM strategies for, and impacts of, space launches


Handling of external risks, including launch and re-entry events, in the aviation and maritime sector


Space traffic management: Towards safe and unsegregated space transport operations

S. Hilton
R. Sabatini
A. Gardi
H. Ogawa
P. Teofilatto


Multi-domain traffic management: Toward integrated air and space transport operations

K. Thangavel
N. E.-D. Safwat
A. Gardi
R. Sabatini

IEEE Aerospace and Electronic Systems Magazine


Predicted trajectory accuracy requirements to reduce aviation impact of space launch operations


Towards Efficient Integration of Rocket Launches and Re-Entry Operations in European Airspace

IAF Symposium on Commercial Spaceflight Safety Issues


Network Effects, Congestion Externalities, and Air Traffic Delays: Or Why Not All Delays Are Evil


Characterization and prediction of air traffic delays


Difference-in-differences with variation in treatment timing


Difference-in-Differences with multiple time periods


Two-way fixed effects and differences-in-differences estimators with heterogeneous treatment effects


Space, the Final Economic Frontier


The Paradigm Shift of NewSpace: New Business Models and Growth of the Space Economy


Engineering the new space economy: Market creation and institutional design

Journal of Industrial and Business Economics


Trade and investment under policy uncertainty: Theory and firm evidence

American Economic Journal: Economic Policy


Comparison of material sources and customer locations for commercial space resource utilization


Atmospheric density-compensating model predictive control for targeted reentry of drag-modulated spacecraft

Journal of Guidance, Control, and Dynamics


Analysis of Uncertainties and Modeling in Short-Term Reentry Predictions


OPUS: An integrated assessment model for satellites and orbital debris / Orbital-use fees and the value of the space industry


Institutions, Institutional Change and Economic Performance


The recent large reduction in space launch cost

48th International Conference on Environmental Systems (ICES)


Cost effectiveness of reusable launch vehicles depending on the payload capacity


Integrating Air Traffic Management and Space Traffic Management: Concepts, Challenges, and Solutions for the Evolving Aerospace Landscape in Europe

Jonas Radtke
Daniel Lück
Lorenz Losensky
Sven Kaltenhaeuser
Christopher Brain
Augustin Udristioiu

Abstract: For decades, the airspace volume above today’s commercial traffic at altitudes higher than 60,000 ft - referred to as Higher Airspace (HA) in Europe, Upper Class E in the U.S. or sometimes Near Space - had been largely reserved for specialized military operations, experimental flights, rare exploration missions, and only occasionally interrupted by rocket launches. However, advancements in aerospace technology, a growing demand for expanded air travel, novel airborne capabilities, and a surge of (commercial) rockets launched to sub-orbital and orbital destinations, let to identifying the need to develop concepts for a more closely interfacing and later-on integration between Air Traffic Management (ATM) and Space Traffic Management (STM). Reasons for this are manifold, but they all can be summed up to the fact that methods developed have been done so in different contexts and different t


Enabling Tactical Airspace Management During Space Launch and Reentry Operations Through Collaborative Information Exchange

Bill Lash
Thomas St. Clair
Catherine Bolczak
Constance Morgan
Duane Freer
Jeffrey Richards


Space Data Integrator: FAA's Innovative Platform for Launch and Reentry Operations

Abstract: In response to the predicted increase in frequency and complexity of commercial launch and reentry operations, the FAA must continue its effort to develop integrated capabilities to meet the Administration’s objectives and realize the anticipated operational benefits of the integration of these operations into the National Airspace System (NAS). The Space Data Integrator (SDI) platform is such a capability that automates the FAA’s currently manual, time-consuming and resource-intensive procedures to support commercial launch and reentry operations. The objectives of the SDI are to allow for extending the operations’ planning to include filing a flight plan, to provide situational awareness to the Joint Space Operations Group (JSpOG) at the FAA Air Traffic Control System Command Center (ATCSCC) on the launch and reentry vehicle position and mission parameters during the full operations, a


Risk Level Analysis for Hazard Area During Commercial Space Launch

Abstract: Current method used for integrating space launch vehicles into National Airspace System (NAS) and reducing aircraft risks includes closing large air space areas to any air vehicles, known as hazard areas. Airspace regulations cause aircraft to reroute increasing flight distance, delays and overall flight cost. Air space restriction area and time are based on profile risk factors of space vehicle launch. This paper describes a method to dynamically construct a risk level map of commercial space launch operations' impact on nearby aircraft. The hazard area is divided into multiple sections, each section is also dynamically evaluated for a risk level, which is a comprehensive index considering the uncertain debris trajectory model and launch failure probabilities. This method provides a framework for modeling an optimal aircraft routing plan within a required risk level.


Generating Realistic Reroutes to Assess Air Traffic Impact of Blocked Airspaces

Abstract: Demand for airspace access has been on the rise due to an increasing number of new entrants such as Space Operators, Unmanned Aircraft Systems (UAS), and Balloon Operators. To accommodate operations such as space launches in the National Airspace System (NAS), the Federal Aviation Administration (FAA) may strategically route traffic around airspaces to ensure operational safety. As the frequency of these activities increases, there is a need to deepen collaboration and transparency between stakeholders regarding airspace usage. A primary need to support this collaboration is the ability to quickly assess traffic impacts due to flights rerouting around airspaces closed due to upcoming operations. Using such a capability, a space operator may be able to adjust their launch and reentry operations plan to have minimal airspace system impact, and a traffic manager may be able to quickly asses


Simulation and Analysis of 4-D Airspace Closures due to Commercial Space Operations: Impacts on Airlines and General Aviation

Janet K. Tinoco
Noah D Eudy
Maxwell Cannon

The Journal of Aviation/Aerospace Education and Research

Abstract: When industries share key portions of their eco-systems, industry-industry competitive and structural pressures can inhibit the advancement of both. In the case of aviation and commercial space, an eco-system component critical to both industries is shared airspace. The integration of air and space activities in a safe, efficient, effective, and equitable manner is compulsory for both industries to grow and thrive. In order to develop solutions, one must first understand the effects of space operations on current national airspace system (NAS) users. By using actual flight data in a simulation environment of space operations out of Cape Canaveral, Florida, we analyze the number and type of impacted flights based on historical airspace closure data. Results indicate that while the majority of the impacted flights were of domestic U.S. carriers, international carrier flights accounted for


Determining Predicted Trajectory Accuracy Requirements to Reduce the Aviation Impact of Space Launch and Reentry Operations

Tim Gruber
Lesley A. Weitz
Nicholas Rozen


Assessing Factors that Affect the Safety of Space Launch and Reentry Operations in the National Airspace System

Zheng Tao
Ganghuai Wang
Jon Semanek
Ashley Williams
Jonathan L. Schwartz


An Airspace Planning and Collaborative Decision-Making Model: Part I—Probabilistic Conflicts, Workload, and Equity Considerations

Hanif D. Sherali
Raymond W. Staats
Antonio Trani

Abstract: We present a large-scale, airspace planning and collaborative decision-making model (APCDM) to enhance the management of the U.S. National Airspace System (NAS). Given a set of flights that must be scheduled during some planning horizon, along with alternative surrogate trajectories for each flight as prompted by various airspace restriction scenarios imposed by dynamic severe weather systems or space launch special use airspaces (SUA), we develop a mixed-integer programming model to select a set of flight plans from among these alternatives, subject to flight safety, air traffic control workload, and airline equity constraints. The model includes a three-dimensional probabilistic conflict analysis, the derivation of valid inequalities, the development of air traffic control workload metrics, and the consideration of equity among airline carriers in absorbing costs related to rerouting,


A Randomized Approach to Probabilistic Footprint Estimation of a Space Debris Uncontrolled Reentry

IEEE Transactions on Intelligent Transportation Systems

Abstract: This paper studies the problem of characterizing the region of the airspace that will be occupied by a space debris during an uncontrolled reentry (footprint), with the final goal of supporting the air traffic controllers in their task of guiding aircraft safely from their origin to their destination. Given the various sources of uncertainty affecting the debris dynamics, the reentry process is characterized probabilistically and the problem of determining the footprint is formulated in terms of a chance-constrained optimization program, which is solved via a simulation-based method. When observations of the debris initial position and radar measurements of the aircraft prior to the reentry event are available, nonlinear filtering techniques can be adopted and the posterior probability distribution of the debris position as well as of the wind field affecting the reentry process can be i


Minimizing Air Traffic Disruption from Uncontrolled Space Debris Reentries

Irina Beatrice Stefanescu
Cristian Emil Constantinescu
Octavian Thor Pleter

Abstract: Uncontrolled space debris reentries pose a significant challenge to air traffic management (ATM), often requiring widespread airspace closures to mitigate the perceived risks to aviation safety. In a previous study, we established the probability of collision during such events to be in the order of 10−7 and classified the event as “extremely remote” but requiring mitigation action. Analyzing the temporal dynamics, we concluded that any given location remains at risk for no more than one minute. Building on these findings, this paper will investigate advanced mitigation strategies to reduce the operational impact of such reentries. We propose utilizing dynamic airspace allocation techniques, using information derived by enhanced reentry prediction models and real-time tracking. Transforming the spatial problem of airspace closures into a temporal one, the study demonstrates the feasibili


Uncontrolled reentries of space objects and aviation safety

Charlotte Hook
Ewan Wright
Michael Byers
Aaron C. Boley

Abstract: There is a growing risk to aircraft in flight from collisions with debris produced by the breakup of uncontrolled rocket bodies and satellites during atmospheric reentry. On one hand, the aviation industry has grown to almost 39 million flights per year, with a 63% increase between 2004 and 2019. On the other hand, the number of successful rocket launches more than doubled between 2015 and 2023, from 87 to 212, respectively. During those 212 launches in 2023 128 rocket bodies were abandoned in orbit, left to reenter uncontrollably. Such uncontrolled space object reentries are hard to predict, making mitigation measures difficult. In November 2022, a reentering Long March 5B rocket caused the closure of airspace over Europe, delaying 645 flights and having a plausible economic impact of millions of Euros. There are international and domestic laws that might enable the recovery of economic


Control and Optimization of Air Traffic Networks

Karthik Gopalakrishnan
Hamsa Balakrishnan

Annual Review of Control Robotics and Autonomous Systems

Abstract: The air transportation system connects the world through the transport of goods and people. However, operational inefficiencies such as flight delays and cancellations are prevalent, resulting in economic and environmental impacts. In the first part of this article, we review recent advances in using network analysis techniques to model the interdependencies observed in the air transportation system and to understand the role of airports in connecting populations, serving air traffic demand, and spreading delays. In the second part, we present some of our recent work on using operational data to build dynamical system models of air traffic delay networks. We show that Markov jump linear system models capture many of the salient characteristics of these networked systems. We illustrate how these models can be validated and then used to analyze system properties such as stability and to de


Characterization of Delay Propagation in the US Air-Transportation Network

Pablo Fleurquin
José J. Ramasco
Victor M. Eguı́luz

Abstract: Abstract Complex networks provide a suitable framework to characterize air traffic. Previous works described the world air-transport network as a graph where direct flights are edges and commercial airports are vertices. In this work, we focus instead on the properties of flight delays in the US air- transportation network. We analyze flight performance data in 2010 and study the topological structure of the network as well as the aircraft rotation. The properties of flight delays, including the distribution of total delays, the dependence on the day of the week and the hour-by-hour evolution within each day, are characterized with special attention to flights accumulating delays longer than 12 hours. We find that the distributions are robust to changes in takeoff or landing operations, different moments of the year, or even different airports in the contiguous states. However, airports


Simulation Analysis on Flight Delay Propagation Under Different Network Configurations

Haoyu Zhang
Weiwei Wu
Shengrun Zhang
Frank Witlox

Abstract: This paper investigates flight delay propagation in air transportation networks (ATNs) by considering both network structures and airport operation performance. An airport susceptible-infected-recovered (ASIR) model is established based on the mechanism of epidemic spreading, where the focus is on the impact of the infection rate in order to properly map and understand the probability of delay propagation. Different network configurations are abstracted under complex network theory, in which the ASIR model can be simulated upon. The simulation results show that the original airport traffic, airport connection and the level of airport turnaround services play important roles in influencing delay propagation in different airports. In addition, changes of network structure such as the emerging of secondary hubs can also influence the delay propagation.


Modeling Flight Delay Propagation in Airport and Airspace Network

Qinggang Wu
Minghua Hu
Xiaozhen Ma
Yaniun Wang
Wei Cong
Daniel Delahaye

2018 21st International Conference on Intelligent Transportation Systems (ITSC)


Systemic delay propagation in the US airport network

Abstract: Technologically driven transport systems are characterized by a networked structure connecting operation centers and by a dynamics ruled by pre-established schedules. Schedules impose serious constraints on the timing of the operations, condition the allocation of resources and define a baseline to assess system performance. Here we study the performance of an air transportation system in terms of delays. Technical, operational or meteorological issues affecting some flights give rise to primary delays. When operations continue, such delays can propagate, magnify and eventually involve a significant part of the network. We define metrics able to quantify the level of network congestion and introduce a model that reproduces the delay propagation patterns observed in the U.S. performance data. Our results indicate that there is a non-negligible risk of systemic instability even under norma


Flight delay propagation modeling: Data, Methods, and Future opportunities

Chi Li
Jianfeng Mao
Lingyi Li
Jingxuan Wu
Lianmin Zhang
Jianyu Zhu
Zibin Pan

Transportation Research Part E Logistics and Transportation Review


Network Effects, Congestion Externalities, and Air Traffic Delays: Or Why All Delays Are Not Evil

Abstract: We examine two factors that might explain the extent of air traffic delays in the United States: network benefits due to hubbing and congestion externalities. Airline hubs enable passengers to crossconnect to many destinations, thus creating network benefits that increase in the number of markets served from the hub. Delays are the equilibrium outcome of a hub airline equating high marginal benefits from hubbing with the marginal cost of delays. Congestion externalities are created when airlines do not consider that adding flights may lead to increased delays for other air carriers. In this case, delays represent a market failure. Using data on all domestic flights by major US carriers from 1988-2000, we find that delays are increasing in hubbing activity at an airport and decreasing in market concentration but the hubbing effect dominates empirically. In addition, most delays due to hub


Stacked Difference-in-Differences

Coady Wing
Seth Freedman
Alex Hollingsworth

Abstract: This paper introduces the concept of a "trimmed aggregate ATT," which is a weighted average of a set of group-time average treatment effect on the treated (ATT) parameters identified in a staggered adoption difference-in-differences (DID) design.The set of identified group-time ATTs that contribute to the aggregate is trimmed to achieve compositional balance across an event window, ensuring that comparisons of the aggregate parameter over event time reveal dynamic treatment effects and differential pre-trends rather than compositional changes.Taking the trimmed aggregate ATT as a target parameter, we investigate the performance of stacked DID estimators.We show that the most basic stacked estimator does not identify the target aggregate or any other average causal effect because it applies different implicit weights to treatment and control trends.The bias can be eliminated using correct


Difference-in-Differences with a Continuous Treatment

Brantly Callaway
Andrew Goodman-Bacon
Pedro H. C. Sant’Anna

Abstract: This paper analyzes difference-in-differences designs with a continuous treatment. We show that treatment-on-the-treated-type parameters are identified under a parallel trends assumption analogous to the binary treatment case. However, comparing these parameters across treatments is challenging because parallel trends does not rule out selection bias. We discuss alternative, typically stronger, assumptions that eliminate selection bias. We further show that popular two-way fixed effects estimands admit multiple interpretations, depending on the underlying causal building block, all having important limitations as meaningful summaries of treatment effects. Finally, we introduce alternative estimation procedures that avoid these drawbacks and demonstrate them in an empirical application.


Difference-in-Differences Estimation with Spatial Spillovers

Abstract: Empirical work often uses treatment assigned following geographic boundaries. When the effects of treatment cross over borders, classical difference-in-differences estimation produces biased estimates for the average treatment effect. In this paper, I introduce a potential outcomes framework to model spillover effects and decompose the estimate's bias in two parts: (1) the control group no longer identifies the counterfactual trend because their outcomes are affected by treatment and (2) changes in treated units' outcomes reflect the effect of their own treatment status and the effect from the treatment status of 'close' units. I propose conditions for non-parametric identification that can remove both sources of bias and semi-parametrically estimate the spillover effects themselves including in settings with staggered treatment timing. To highlight the importance of spillover effects, I


Interpreting Event-Studies from Recent Difference-in-Differences Methods

Abstract: This note discusses the interpretation of event-study plots produced by recent difference-in-differences methods. I show that even when specialized to the case of non-staggered treatment timing, the default plots produced by software for several of the most popular recent methods do not match those of traditional two-way fixed effects (TWFE) event-studies. The plots produced by the new methods may show a kink or jump at the time of treatment even when the TWFE event-study shows a straight line. This difference stems from the fact that the new methods construct the pre-treatment coefficients asymmetrically from the post-treatment coefficients. As a result, visual heuristics for evaluating violations of parallel trends using TWFE event-study plots should not be immediately applied to those from these methods. I conclude with practical recommendations for constructing and interpreting event


How much should we trust staggered difference-in-differences estimates?

Andrew C. Baker
David F. Larcker
Charles C. Y. Wang

Abstract: We explain when and how staggered difference-in-differences regression estimators, commonly applied to assess the impact of policy changes, are biased. These biases are likely to be relevant for a large portion of research settings in finance, accounting, and law that rely on staggered treatment timing, and can result in Type-I and Type-II errors. We summarize three alternative estimators developed in the econometrics and applied literature for addressing these biases, including their differences and tradeoffs. We apply these estimators to re-examine prior published results and show, in many cases, the alternative causal estimates or inferences differ substantially from prior papers.


Synthetic difference-in-differences estimation with staggered treatment timing


Difference-in-Differences Estimators of Intertemporal Treatment Effects

Clément de Chaisemartin
Xavier D’Haultfœuille


Analysis of Reentry Prediction of CZ-5B Rocket Body

Jaedong Seong
Okchul Jung
Youeyun Jung
Daewon Chung

Journal of Space Technology and Applications

Abstract: This paper represents a reentry time prediction analysis of CZ-5B rocket-body in China, subject to analysis of the Inter-Agency Space Debris Coordination Committee Reentry (IADC) reentry test campaign conducted in May 2021. Predicting the reentry of space objects is difficult to accurately predict due to the lack of accurate physical information about target, and uncertainty in atmospheric density. Therefore, IADC conducts annual re-entry campaigns to verify analysis techniques by each agency, and the Korea Aerospace Research Institute has also participated in them since 2015. Ballistic coefficient estimation method proposed to predict target reentry time and the result confirmed the difference of 73 seconds, which confirms the accuracy of the proposed method.


Performance Evaluation of Atmospheric Density Models for Satellite Reentry Predictions with High Solar Activity Levels.

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

Abstract: In order to estimate the intrinsic accuracy of satellite reentry predictions, the residual lifetimes of 11 spacecraft and five rocket bodies, covering a broad range of inclinations and decaying from orbit in a period of high solar activity, were determined using three different atmospheric density models: JR-71, TD-88, and MSIS-86. For each object, the ballistic coefficient applicable to a specific phase of the flight was obtained by fitting an appropriate set of two-line orbital elements, while the reentry predictions were computed approximately one month, one week and one day before the final orbital decay. No clear correlation between the residual lifetime errors and satellite inclination or type (spacecraft or rocket body) emerged. JR-71 and MSIS-86 resulted in good agreement, with comparable reentry prediction errors (∼10%), semimajor axis residuals, and ballistic coefficient estima


Ballistic Coefficient Estimation for Reentry Prediction of Rocket Bodies in Eccentric Orbits Based on TLE Data

David J. Gondelach
Roberto Armellin
Aleksander Lidtke

Abstract: Spent rocket bodies in geostationary transfer orbit (GTO) pose impact risks to the Earth’s surface when they reenter the Earth’s atmosphere. To mitigate these risks, reentry prediction of GTO rocket bodies is required. In this paper, the reentry prediction of rocket bodies in eccentric orbits based on only Two‐Line Element (TLE) data and using only ballistic coefficient (BC) estimation is assessed. The TLEs are preprocessed to filter out outliers and the BC is estimated using only semimajor axis data. The BC estimation and reentry prediction accuracy are analyzed by performing predictions for 101 rocket bodies initially in GTO and comparing with the actual reentry epoch at different times before reentry. Predictions using a single and multiple BC estimates and using state estimation by orbit determination are quantitatively compared with each other for the 101 upper stages.


Tracking reentries of Starlink satellites during the rising phase of solar cycle 25

Denny M. Oliveira
E. Zesta
Katherine Garcia‐Sage

Frontiers in Astronomy and Space Sciences

Abstract: The exponential increase of low-Earth orbit (LEO) satellites in the past 5 years has brought into intense focus the need for reliable monitoring and reentry prediction to safeguard from space collisions and ground debris impacts. However, LEO satellites fly within the upper atmosphere region that exerts significant drag forces to their orbits, reducing their lifetimes, and increasing collision risks during dynamic events, like geomagnetic storms. Such conditions can become more severe during geomagnetic storms, particularly during extreme events. In this work, we use two-line element (TLE) satellite tracking data to investigate geomagnetic activity effects on the reentries of 523 Starlink satellites from 2020 to 2024. This period coincides with the rising phase of solar cycle 25, which has shown itself to be more intense than the previous solar cycle. We derive satellite altitudes and ve


Orbital debris and the market for satellites

Abstract: This paper studies the economic consequences of orbital debris for commercial outer-space activities. Spacecraft launches and other outer-space human activities produce pollution (i.e., orbital debris), which represent a hazardous negative externality increasing the risk of collision and the destruction of satellites. We regard outer space as a global common resource, where firms operating satellites maximize profits and do not internalize the social cost of orbital pollution. We develop a dynamic investment model for satellites and simulate the calibrated model to estimate how debris affects the optimal quantity of satellites and launches, and the number of satellites destroyed by collisions. We find that the optimal quantity of satellites is a negative function of the amount of debris. The paper derives a simple expression for the maximum number of satellites to prevent the Kessler syn


Public–private partnerships in fostering outer space innovations

Gordon C. Rausser
Elliot Choi
Alexandre M. Bayen

Proceedings of the National Academy of Sciences

Abstract: As public and private institutions recognize the role of space exploration as a catalyst for economic growth, various areas of innovation are expected to emerge as drivers of the space economy. These include space transportation, in-space manufacturing, bioproduction, in-space agriculture, nuclear launch, and propulsion systems, as well as satellite services and their maintenance. However, the current nature of space as an open-access resource and global commons presents a systemic risk for exuberant competition for space goods and services, which may result in a "tragedy of the commons" dilemma. In the race among countries to capture the value of space exploration, NASA, American research universities, and private companies can avoid any coordination failures by collaborating in a public-private research and development partnership (PPRDP) structure. We present such a structure founded


The Economics and Policy of Space Debris and Orbital Management

The Oxford Handbook of the New Space Economy

Abstract: Abstract Satellites are at risk of collision with each other as well as with other space debris. As the number of satellites and amount of debris increase, so does the risk of collision. The risk is therefore cascading in nature. A small set of incidents can accumulate and lead to catastrophic damages or destruction of many satellites and render some orbital regions too polluted for use. This chapter provides a foundation for understanding this issue as a commons management problem. It defines orbitals carefully and provides selective information and facts about their use. The chapter discusses orbitals in terms of the economic principles of rivalry and excludability, which are critical for understanding the commons problem, and offers a framework for valuing the issue and finding workable policy solutions. Notwithstanding the nascent economic literature on this topic, some estimates of


Benefit-Sharing as Investment Protection for Space Resource Utilization

Petr Bohacek
Simon P. Worden
Kyran Grattan

Abstract: Despite the adoption of several national space mining legislations, Space Resource Utilization (SRU) suffers from international legal ambiguity that increases investment risks. We consider the vagueness of the benefit-sharing requirements from space activities under the Outer Space Treaty Article I to be the main legal gap regarding SRU. To increase private investments into the SRU sector, we offer a way to address the legal uncertainty. We argue that: (1) there is a low likelihood of an emergence of a new international space-mining regime that would fix this uncertainty, and (2) the relatively low knowledge regarding the required processes, technologies, and final benefits of SRU prevent us from designing an effective, functional, and flexible way of sharing the benefits without significantly constraining private investments. As a fix we provide an investor-oriented approach that (1) sh


Cross-Domain Lessons for Space Traffic Management: An Analysis of Air and Maritime Treaty Governance Mechanisms


The Cologne Manual on Space Traffic Management (CM-STM) : co-operation project between the Institute of Air Law, Space Law and Cyber Law at the University of Cologne and the German Aerospace Center (DLR)

Kölner Universitäts PublikationsServer (Universität zu Köln)

Abstract: The "Cologne Manual on the International Law of Space Traffic Management – für die sichere und nachhaltige Nutzung des Weltraums im 21. Jahrhundert" (for the safe and sustainable use of space in the 21st century) is an international research project as well as a cooperation project between the German Aerospace Centre (DLR) and the Institute of Air Law, Space Law and Cyber Law at the University of Cologne. The result is a Manual on Space Traffic Management (STM) in the sense of traffic rules portraying a scientific study additionally.


On the need to assess and mitigate the risk from uncontrolled re-entries


The risk on the ground and in the airspace posed by uncontrolled re-entries: Should the growth observed in recent years be considered worrying?


Re-entry survival analysis and ground risk assessment of space debris


Decay time estimate for LEO spacecraft


Space traffic management: Large constellations


Space capacity management and its interaction with space traffic management


Design-based Analysis in Difference-In-Differences Settings with Staggered Adoption


Identification of quantile treatment effects in difference-in-differences settings with staggered adoption


Modern Staggered Difference-in-Differences: From the Pitfalls of Two-Way Fixed Effects (TWFE) to Robust Estimation


Prosecutors and crime deterrence: Evidence from a difference-in-differences analysis with staggered treatment


National AI Strategies and Macroeconomic Performance A Staggered Difference-in-Differences Approach

Abstract: Governments worldwide have responded to the rise of artificial intelligence by publishing National AI Strategies (NAS), comprehensive policy documents that allocate public R&D funding, establish AI education programs, create governance frameworks, and signal long-term commitment to AI-driven transformation. This paper provides the first cross-country causal evaluation of these policy responses on macroeconomic outcomes. Exploiting the staggered adoption of NAS across 44 countries between 2017 and 2022 as a natural experiment, we estimate the average treatment effect on GDP per capita growth using a balanced panel spanning 2010 to 2024. Our main specification employs the Callaway and Sant’Anna (2021) doubly robust estimator, supplemented by five additional robust estimators. We find a consistent, statistically significant negative effect of NAS adoption on GDP per capita growth of app


Preliminary Evaluation of Flight Delay Propagation through an Airline Schedule

Roger Beatty
Rose Hsu
Lee Berry
James Rome


Modeling flight delay propagation: A new analytical-econometric approach

Transportation Research Part B: Methodological


A data-driven method to assess the causes and impact of delay propagation in air transportation systems

Vaggelis Giannikas
Anna Ledwoch
Goran Stojković
Pablo Costas
Alexandra Brintrup
Ahmed Ali Saeed Al-Ali
Vinod Kumar Chauhan
Duncan Mcfarlane

Transportation Research Part C Emerging Technologies


Building Reliable Air-Travel Infrastructure Using Empirical Data and Stochastic Models of Airline Networks

Mazhar Arıkan
Vinayak Deshpande
Milind Sohoni

Abstract: Flight delays have been a growing issue and they have reached an all-time high in recent years, with the airlines' on-time performance at its worst level in 2007 since 1995. A recent report by the Joint Economic Committee of the U.S. Congress chaired by Senator Charles E. Schumer has estimated that the total cost to the U.S. economy because of flight delays was as much as $41 billion in 2007. The goal of this paper is to build stochastic models of airline networks and utilize publicly available data to answer the following policy questions: Which are the bottleneck airports in the U.S. air-travel infrastructure (i.e., airports that cause most delay propagation)? How would increasing airport capacity at these airports alleviate delay propagation? What are the appropriate metrics for measuring the robustness of airline schedules? How could these schedules be made more robust? Which flight


On the Implementation of a European Space Traffic Management System I. A White Paper.

Ralph Tüllmann
Christian Arbinger
Stuart Baskcomb
Jens Berdermann
Hauke Fiedler
Erich Klock
Thomas Schildknecht

Bern Open Repository and Information System (University of Bern)

Abstract: There are high expectations for a global commercial space travel market which is expected to turn into a multi-billion Euro business in the next two decades. Several key players in the space business, companies like Virgin Galactic, SpaceX, Blue Origin or SNC are preparing to serve this market by developing their own ballistic reusable space vehicles to carry humans and cargo payloads into suborbital and Low Earth Orbit (LEO) space. Europe’s single stage to orbit concepts, e.g., REL’s Skylon or Airbus’ Spaceplane, go even further and target for manned suborbital point-to-point (p2p) transportation, similar to today’s travel through airspace, but with much shorter flight times. All these developments will likely stimulate demands for new infrastructure (e.g., for spaceports, tracking & surveillance networks or control centres), requiring the implementation of adequate Space Traffic Manage


A Dynamic Air Traffic Management Approach to Operationally Responsive Space

James Torres
P. Röhl
Jimmy Krozel
Terry L. Thompson

AIAA Atmospheric Flight Mechanics Conference and Exhibit

Abstract: The existing Air Traffic Management (ATM) system can evolve into a Space and Air Traffic Management System (SATMS), as space operations become a more common event. An assessment tool has been developed as a catalyst for this evolution; the Dynamic Flight Path Tool was developed to utilize real time situational information to minimize the impact of space flight to operations while at the same time ensuring a level of safety acceptable to the public. This tool capitalizes on methods that rapidly compute the debris clouds within a four-dimensional space (3D space plus time). The tool has two modes of operation: 1) Pre- mission Planning and 2) Real-time Mission Mode. The Dynamic Flight Path Tool has been applied to a range of sample scenarios that demonstrate how the impact of space launch operations on air traffic can be significantly reduced. 1 . An assessment tool has been developed as a


Uncontrolled Re-entry Risk for Aviation and the benefits of real time information services

Sven Kaltenhäuser
Tobias Rabus
D W Freer
Dan Bogdan

Abstract: The increasing number of satellites and space debris reentering Earth's atmosphere poses significant challenges to aviation safety, particularly due to the unpredictability of uncontrolled reentries. With the rapid growth of satellite constellations, these events are expected to increase, and despite advancements in tracking systems and controlled reentry technologies, many reentries remain difficult to predict. While real-time monitoring tools such as the U.S. Space Data Integrator (SDI) and Europe's SpaceTrack offer critical support for Air Navigation Service Providers (ANSPs) to manage debris events, a gap persists in addressing the hazards posed by uncontrolled reentries. The main challenge lies in the timing and precision of reentry predictions. Current hazard areas are often too large to manage effectively. The size of the hazard area combined with the uncertainty of location can l


Enhanced Covariance Propagation for Asymmetric High-Order Uncertainty in Reentry Debris Risk Prediction

Abstract: Abstract his study presents a comprehensive experimental analysis of suborbital debris propagation under various uncertainty scenarios, focusing on the effects of kinematic perturbations and area-to-mass ratio diversity. The equations of motion, incorporating gravitational and aerodynamic forces, are analytically simplified to characterize the asymmetric expansion of debris clouds. A multi-dimensional sampling strategy based on the NASA Standard Breakup Model is adopted, and propagation experiments are conducted to quantify spatial dispersion and risk envelopes across both horizontal and vertical-longitudinal projections. The results reveal that initial velocity increments and variations in area-to-mass ratio significantly amplify the anisotropic spread of debris, leading to pronounced asymmetry in the hazard zone boundaries. Comparative evaluation demonstrates that the proposed estimati


Global thermospheric neutral density and wind response to the severe 2003 geomagnetic storms from CHAMP accelerometer data

Journal of Geophysical Research Atmospheres

Abstract: Measurements of atmospheric density near 410 km from the STAR accelerometer on the CHAMP satellite are used to illustrate the spatial‐temporal dependence of the thermospheric response to the severe solar storms occurring during 29 October to 1 November 2003. This interval includes periods of elevated magnetic activity with K P values of 5–9, as well as undisturbed intervals that serve to define quiet time baseline densities. Measurements are available from −87° to +87° latitude during both day and night at local times near 1300 and 0100 hours, respectively. During times of maximum geomagnetic activity for this study, density measurements exhibit enhancements of 200–300%. Northern Hemisphere daytime responses are much larger than in the Southern Hemisphere; the origins of this effect are unknown. Nighttime density disturbances more readily propagate to equatorial latitudes, possibly facil


Evidence of long term global decline in the Earth's thermospheric densities apparently related to anthropogenic effects

G. M. Keating
R. H. Tolson
M. S. Bradford

Abstract: A study was performed of the long‐term orbital decay of five Earth satellites with perigee altitudes averaging near 350km. To decouple long‐term trend measurements from the effects of solar variability, measurements were evaluated during the years of solar minimum (1976, 1986 and 1996). Atmospheric densities derived from these essentially global measurements showed substantial evidence of a decline averaging 9.8 ± 2.5% in thermospheric density over 20 years pointing toward a long‐term cooling of the upper atmosphere. Increases in greenhouse gases induced by human activity are hypothesized to warm the Earth's surface and lower atmosphere, but strongly cool the upper atmosphere. Assuming that the 10% increase in CO 2 over these 20 years caused cooling resulting in the 10% decline in density, a doubling of CO 2 could cause the thermospheric densities measured near 350km to decrease by a fac


Deciphering Solar Cycle Influence on Long-Term Orbital Deterioration of Low-Earth Orbiting Space Debris

Ayisha M Ashruf
Ankush Bhaskar
Vineeth, C
Pant, Tarun Kumar

Abstract: The rapid increase in the number of space debris represents a substantial threat to the sustained viability of space operations and underscores the importance of understanding long-term drivers of orbital decay. This first of its kind study examines the long-term impact of solar activity on the orbital decay of 17 LEO debris objects across Solar Cycles 22, 23, and 24 using Two-Line Element (TLE) data spanning these three cycles. Analysis of TLE-derived decay profiles, in conjunction with sunspot numbers (SSN) and F10.7 index, reveals a threshold: orbital decay rates increase sharply when SSN exceeds approximately 67-75% of its cycle peak. This threshold corresponds to enhanced thermospheric density driven by elevated solar input, resulting in increased atmospheric drag. The orbital decay rates at the peak of each solar cycle show a progressive decline from Cycle 22 to Cycle 24, mirroring


Road Pricing for Congestion Management: The Transition from Theory to Policy

Abstract: Traffic congestion is a classic externality, especially pervasive in urban areas. The theoretical and empirical relationships governing it have been thoroughly studied. As a result, there is a consensus among urban economists, and a growing number of other analysts, that the best policy to deal with it would be some form of congestion pricing. Such a policy involves charging a substantial fee for operating a motor vehicle at times and places subject to peak demands. The intention is to alter people’s travel behavior enough to reduce congestion.


Does Britain or the United States Have the Right Gasoline Tax?

Abstract: This paper develops an analytical framework for assessing the second-best optimal level of gasoline taxation taking into account unpriced pollution, congestion, and accident externalities, and interactions with the broader fiscal system. We provide calculations of the optimal taxes for the US and the UK under a wide variety of parameter scenarios.&nbsp;Under our central parameter values, and with the gasoline tax substituting for a distorting tax on labor income, the second-best optimal gasoline tax is $0.95/gal for the US and $1.29/gal for the UK. These values are moderately sensitive to alternative plausible parameter assumptions. The congestion externality is the largest component in both nations, and the higher optimal tax for the UK is due almost entirely to a higher assumed value for marginal congestion cost. Revenue-raising needs, incorporated in a “Ramsey" component, also pla


Space Accommodation Operations: Maximizing Efficiency in Orbital Facilities

Smriti Tandon
Antonia Puccio
Subhankar Das

Pioneering the New Space Economy through AI and Immersive Technologies


Outreach on Space Traffic Management


The need to improve registration practices in the context of space traffic management