Rapidly evolving drone technologies are taking the conservation sector by storm. Although the technical and applied conservation literature tends to frame drones as autonomous, neutral technologies, ...we argue that neither drones nor their implications can be adequately understood unless they are grounded, conceptually and methodologically, in the context of broader societal structures that shape how drones and the data they produce are used. This article introduces the value of a political ecology framework to an interdisciplinary audience of biophysical and social scientists interested in the multiple possibilities and complications associated with conservation drones. Political ecology provides the tools for studying and critically engaging with drone use in conversation in ways that are politically engaged and attuned to power relations – historic and present, local and global – in a more-than-human world. In making this argument, we point to four conceptual tools in political ecology that offer a framework for unveiling the power relations and structures that surround drones in different contexts: political economy, territoriality, knowledge and expertise, and more-than-human relations. Using empirics from our work across Latin America (Colombia and Guatemala), Africa (Kenya, Tanzania, South Africa and Mozambique), and North America (the US and Canada), we illustrate the salience of this framework and demonstrate why evaluating what drones do in and for conservation requires first understanding the complex set of power relations that shape their use.
This commentary addresses the use of surveillance technologies in the context of the Covid-19 pandemic, using examples from the current geopolitical frame, and questioning the possible consequences ...of data collection for the individual and for society. In this regard, some questions emerge: in the fight against the pandemic, what measures and tools of surveillance are being adopted by the different states? Will the extraordinary measures, that are now being implemented, become permanent? And if so, what will the consequences be for privacy and democracy?
A number of countries in the Global South have adopted anti-China rhetoric in recent years. Here, we seek to assess the relation of such rhetoric to procurement of Chinese digital systems. We use the ...example of Brazil during the Bolsonaro government, examining whether Bolsonaro's anti-China stance impacted procurement of Chinese surveillance technologies by sub-national (state/city) governments, which are the main bodies responsible for public security. We find that there has been broad and sustained procurement of Chinese surveillance technologies across the political spectrum; both among local governments politically allied to Bolsonaro and those from the opposition. Combined with acquisition at federal level, this suggests anti-China rhetoric does not feed through into procurement realities. Nor can China be singularly associated with diffusion of surveillance technologies as Western democracies have also been suppliers.
Maneuver detection and estimation is deemed crucial for maintaining catalogs of Resident Space Objects (RSOs) as it helps to avoid sets of duplicated objects and track correlation issues. In fact, ...maneuvers, along with launches and break-up events, are the main source of potential new object detections during RSOs cataloging activities. For the continuous and reliable provision of Space Situational Awareness (SSA) and Space Traffic Management (STM) services, a challenging trade-off between detection time and characterization accuracy of maneuvers needs to be performed. In this paper, two novel and operationally feasible methodologies are proposed for maneuver detection and estimation. The first, a track-to-orbit methodology, uses a pre-maneuver orbit to linearize the dynamics and estimate the single burn that minimizes the residuals of the post-maneuver tracks. The second, an orbit-to-orbit methodology, estimates the double burn that solves a minimization problem between the pre-maneuver and post-maneuver orbits. Both methods, based on an optimal control approach, are not only proposed to tackle the maneuver estimation problem but also to be integrated on operational and robust association frameworks. Results are presented for optical scenarios with both simulated and real data, providing insightful conclusions on the capabilities, performance and limitations of the proposed methods. Particular emphasis is given to the importance of the track association, since a single track is usually not enough to perform a reliable estimation of the maneuver. Besides, the capability of the methods to provide a solution to the association problem, even when not perfectly characterizing the true maneuver, is discussed.
Simulations of spacecraft breakup events in low lunar orbit are conducted with the aim of determining the longevity of the resulting debris and the hazards it could pose. The trajectories of ...approximately 97,000 debris particles across eight Monte Carlo breakup simulations are propagated for 1 year using a high-precision lunar trajectory model. Debris was found to be especially long-lasting for breakups in circular polar orbits at 200 km altitude, in retrograde equatorial orbits at 100 km or higher, and in lunar frozen orbits. Analysis of the locations at which polar-orbiting debris tended to impact the Moon reveals a surprising asymmetry and significant accumulations in certain regions. Finally, estimates of the collision probability over 1 year to other notional spacecraft varied from
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, suggesting a low risk of collision, but a significant number of close approaches within 5 km were observed. The results of this study provide new insights into the overall behavior of debris in lunar orbit and improve understanding of the consequences of a debris event in this orbital environment.
A novel multi-objective Monte Carlo Tree Search (MO-MCTS) algorithm is developed and implemented for use in architecture design problems. This algorithm is used with two well-known problems with ...known solutions in order to verify its performance. It is then used in a highly nonlinear Cislunar architecture design problem with no known analytical solutions. The results of this implementation display the ability of MO-MCTS to effectively navigate the state space of mixed integer nonlinear programming problems and emphasize the versatility of MO-MCTS for designing critical Cislunar architecture.
We introduce a methodology for estimating the risk posed to the space environment by a spacecraft over an arbitrary period of time following a risk mitigation strategy, in terms of aggregate ...collision probability. Our methodology enables estimation of residual risk and maneuver frequency, where residual risk is defined conceptually as the risk to a spacecraft which remains even after adherence to a risk mitigation strategy. The key parameters considered which affect residual risk for a general risk mitigation strategy are the risk mitigation maneuver (RMM) threshold, the risk reduction factor, and the maneuver execution time. We present an analytic result regarding the necessary residual risk (per-satellite) to ensure the total aggregate collision probability of a satellite constellation of arbitrary size be below a target value. This approach offers a more complete model of spacecraft safety and potential risk to the space environment by studying more than just the RMM threshold, which has historically been used as a common benchmark in space situational awareness and regulatory compliance literature. Our analysis shows that the RMM threshold is but one of a few factors which have significant effects on residual risk. We provide evidence that the RMM threshold alone is an incomplete indicator of the actual risk posed to the space environment by an operational spacecraft. We demonstrate the effectiveness of this methodology by presenting numerical results which model realistic satellites and satellite constellations and draw key insights from this analysis which will aid in managing the safety and sustainability of the space environment and inform risk mitigation strategies for large satellite constellations.
The development of large constellations of satellites (i.e., so-called megaconstellations or satcons) is poised to increase the number of LEO satellites by more than an order of magnitude in the ...coming decades. Such a rapid growth of satellite numbers makes the consequences of major fragmentation events ever more problematic. In this study, we investigate the collisional risk to on-orbit infrastructure from kinetic anti-satellite (ASAT) weapon tests, using the 2019 Indian test as a model. We find that the probability of one or more collisions occurring over the lifetime of ASAT fragments increases significantly in a satcon environment compared with the orbital environment in 2019. For the case of 65,000 satellites in LEO, we find that the chance of one or more satellites being struck by ASAT fragments of size 1 cm or larger is more than 25% for a single test. Including sizes down to 3 mm in our models suggests that impacts will occur for any such event. Finally, we apply our methods to examine the November 2021 Russian ASAT test, also finding a significant collision probability over the lifetime of the fragments. The heavy commercialization of LEO demands a commitment to avoiding debris-generating ASAT tests.
International interest in the sustained development of cislunar space will generate traffic and debris in the region which requires monitoring; similar to how current space situation awareness is ...necessary for the traffic and debris near Earth. There are many challenges associated with developing a cislunar situation awareness program, but 2 primary issues addressed by this paper are observational strategies and maneuver detection methods. This work proposes an observational strategy that utilizes the ballistic Optimal Control Based Estimator (OCBE) to filter measurements from cislunar optical observers. To reduce numerical issues associated with filtering, new modifications to the ballistic Optimal Control Based Estimator (OCBE) are introduced that preserve the OCBE update equations in Square Root Information (SRI) space. This new derivation produces a more stable version of the ballistic OCBE which is beneficial for filtering larger data sets with non-linear motion and measurements. Applying the SRI OCBE to the estimation problem it was found that only a single L2 observer with angle and angle-rate measurements provided sufficient information for consistent estimation. Then a newly developed maneuver detection method is presented to statistically identify maneuvers. The method applies a binary hypothesis test to the optimal control policy of the ballistic OCBE to quantify mismodeling. This method was tested given a impulsive maneuver policy with a mean of 50 mm/s and standard deviation of 15 mm/s, and 194 out of 200 tests correctly identified if a maneuver occurred. The OCBE control policy also provided appropriate impulse estimates of mismodeling, which may be used to reconstruct maneuvers in future work. Together, the proposed observation and maneuver detection methodology yields reliable tracking and provides a statistical framework to detect maneuvers.
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