This workshop will explore the possibilities of increasing the networking of actors involved in the process of discovering, acknowledging, tracking and observing NEO imminent impactors. Building up on the recent occurrence of the impact of 2022 EB5 on 11 March 2022, EU and ESA want to increase the level of coordination and cooperation between all those actors, which include asteroid discoverers and observers, NEOCP object analysts, spacecraft operators and fireball network operators. Goals of the workshop are to establish a network of related experts and a communication protocol to ensure that the imminent impactor relevant information reaches all possible interested parties.
Programme of the European Union, implemented by ESA.
Introduction by ESA and by the EC.
A number of automatic tools are currently in place to warn on the possibility of an NEO impact with the Earth (ESA's Meerkat, JPL's Scout and NEODyS' NEOScan). This session is targeted to presenting advances or updates to those tools and new developments.
Near-Earth asteroids that have the potential to impact on our planet essentially on the orbit in which they are discovered, without any substantial perturbation preceding the impact, are often called 'immediate impactors', and deserve special efforts to improve their observational record. Even in cases in which the extension of the observed arc allows to exclude a direct collision, however, there is the possibility of further collisions in the following years, associated to resonant returns. These have, in general, much lower probabilities compared to a direct hit, nevertheless may still be important, especially if the resonant return takes place after a small number of years. We use the analytical theory of close encounters to identify regions in the orbital parameter space where this phenomenon may be more significant.
The MPC NEO Confirmation Page (NEOCP) plays a crucial role in the discovery and follow up of Near-Earth Objects. Once a candidate new object has been observed and observations have been posted to the Minor Planet Center (MPC), the MPC’s aim is to process the object in the shortest amount of time. The goal is to give the community a reasonable and reliable area in the sky in which the object can be followed up and confirmed. When the entire process is successfully completed, the object gets a provisional designation and observations and orbits are published through a minor planet circular. Most of the time, this process is smooth and completely automated. We will give a brief introduction on how the internal MPC pipeline works for new discoveries and follow up, and demonstrate the rapid turnaround in the case of 2022 EB5, the object that impacted the Earth in March 2022.
There are cases in which problems or latencies appear, slowing down the entire follow up and discovery procedure. We will present our recent developments on improving latencies and accuracy of the NEO discovery. We will show where the bottlenecks appear and how we plan to overcome them.
We will also present our plans for the future, when the MPC will need to ingest hundreds of thousands of observations per night from the Vera Rubin Observatory and the NEO Surveyor mission.
It typically takes a few days for a newly discovered near-Earth asteroid to be officially recognized as a real object and designated by the Minor Planet Center. During this time, the tentative discovery is published on the Near-Earth Object Confirmation Page until additional observations confirm that the object is in fact a real asteroid rather than an observational artifact or an artificial object. Among these candidate discoveries there can be short-term impactors, as was the case for 2008 TC3 and 2014 AA, the first two objects discovered prior to reaching the Earth. Both objects were a few meters in size and were first detected 20 hours before impact. Given the potentially short time interval between discovery and impact for small asteroids, we developed Scout, an automated system that provides an orbital and hazard assessment for newly discovered asteroids within minutes after the observations are available. Scout overcomes the orbit determination degeneracies typical of short observation arcs using systematic ranging, a technique that scans a grid in the poorly constrained space of topocentric range and range rate, while the plane-of-sky position and motion are directly tied to the recorded observations. This scan allows us to derive a distribution of the possible orbits and in turn identify the objects that have a significant chance of impact, in which case Scout also estimates the possible impact locations. The results of the analysis and ephemerides are readily publicly available on the JPL Center for Near-Earth Object Studies website to guide follow-up efforts by the observing community. Two of the main highlights since Scout started operating in late 2016 were the impacts of 2018 LA and 2022 EB5, both a few meters in size. Despite being discovered within hours of impact, Scout successfully predicted their atmospheric entry above Botswana and the Norwegian Sea, respectively.
This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration, USA (80NM0018D0004).
The European Space Agency (ESA) developed an independent imminent impactor warning service, called Meerkat Asteroid Guard (Meerkat for short). The fully automated system is running 24/7 and analyses newly discovered near-Earth objects, published on the NEO Confirmation Page of the Minor Planet Center. Meerkat uses the Systematic Ranging technique to compute a preliminary orbit and to detect potential impacts. In addition, the system is searching for close approaching objects, interior-Earth objects and potential interstellar objects. If a notable object was found, Meerkat automatically informs subscribers via e-mail. In addition, all computation results can be accessed via a website or an API request. The access is currently restricted since the software is in the validation process.
Meerkat was designed in close collaboration with observers to fit their needs. Therefore, specialized plots help observers to estimate the real threat of a potential impactor and reduce the effort of finding well-fitting observatories for follow-up observations. Based on the preliminary orbits, Meerkat offers the service to compute ephemeris for follow-up observations. A feature is the option to exclude non-impacting solutions.
Among the main imminent impactor warning systems, Meerkat was the first to trigger an alert about the object Sar2593 on 11 March 2022 at 20:23 UTC. At this time, the impact location was already constrained to about a thousand kilometers with an impact time between 21:21 and 21:25 UTC, so only one hour later. Due to follow-up observations, the time and location of the impact could be better constrained in the next hours. Sar2593, later designated as 2022 EB5, entered the atmosphere at approximately 21:23 UTC at the predicted area. This object has been the first imminent impactor since the launch of Meerkat and demonstrated the system’s capabilities.
The imminent impactors are a challenge for the overall system, because we expect they are generally small in size and discovered just a few days or even few hours before the impact, as was the case for 2008 TC3, 2014 AA and others. The time, therefore, is the biggest concern and the system must react quickly and efficiently, trying to involve as soon as possible worldwide professionals but also amateurs. In this presentation we show the state of the art and the weak points of the present system, and we propose some solutions aiming to improve the efficiency and reactivity of the overall system, such as the NEOScan tool developed in NEODyS and the priority lists.
A number of automatic tools are currently in place to warn on the possibility of an NEO impact with the Earth (ESA's Meerkat, JPL's Scout and NEODyS' NEOScan). This session is targeted to presenting advances or updates to those tools and new developments.
NEOROCKS (Near-Earth Object Rapid Observation, Characterization and Key Simulations) is a European project funded by the UE Horizon 2020 programme whose aim is to increase our knowledge of the NEO physical characterization through observations and data dissemination. The organization of a “Rapid Response Experiment” relying on existing European assets is one of the project key activities and it was successfully carried out in April 2022. Lessons learned from trying to minimize human intervention for optimizing the process in view of the expected near future sharp increase of NEO discoveries are discussed.
NEOROCKS is an international consortium involving Italy, France, UK, Czech Republic, Spain, Romania and Poland, coordinated by INAF and with the participation of: S. Anghel, M. Banaszkiewicz, S. Banchi, M. A. Barucci, F. Bernardi, A. Bertolucci, M. Birlan, B. Carry, A. Cellino, F. Calderini, F. Colas, J. De Léon, A. Del Vigna, A. Dell’Oro, A. Di Cecco, L. Dimare, I. Di Pietro, E. Dotto, P. Fatka, A. Flores-Garcia, S. Fornasier, E. Frattin, P. Frosini, M. Fulchignoni, R. Gabryszewski, M. Giardino, A. Giunta, J. Huntingford, T. Hromakina, S. Ieva, J.P. Kotlarz, F. La Forgia, M. Lazzarin, J. Licandro, E. Mazzotta Epifani, H. Medeiros, A. Mediavilla, F. Merlin, J. Nomen Torres, D. Perna, E. Perozzi, V. Petropoulou, F. Pina, G. Polenta, M. Popescu, P. Pravec, A. Rozek, P. Scheirich, A. Sergeyev, A. Sonka, C. Snodgrass, B. Teodorescu, G.B. Valsecchi, P. Wajer, A. Zinzi.
The 60/90/180 cm Schmidt telescope of the Konkoly Observatory, located at the Piszkéstető Mountain Station in Hungary, has always been a discovery machine.
In the first three decades of operations as a photographic instrument with a 5 degree field of view, it has resulted in the discovery of 47 supernovae, five comets and ten minor planets. The photographic plates were replaced by CCD cameras in the late 1990s, and in the last five years we performed an upgrade that led to a 9 square degrees field of view. With this upgrade and new observing strategies, we have discovered more than eighty NEOs during two years.
Of these one was 2022 EB5, the fifth known asteroid to have been discovered before it impacted the Earth. Although physically small, this minor body (with a size of a “half-giraffe”, an expression that turned quickly into various memes in the social media) highlighted very important lessons on the technical and scientific aspects, not to mention possible broader impacts on the society in regards of the importance of planetary defense.
A number of automatic tools are currently in place to warn on the possibility of an NEO impact with the Earth (ESA's Meerkat, JPL's Scout and NEODyS' NEOScan). This session is targeted to presenting advances or updates to those tools and new developments.
Survey systems and telescopes are of paramount importance in the discovery of imminent impactors. State of the art and future additions to the network of telescopes will be portrait in this session.
Although Pan-STARRS is yet to discover an impacting asteroid, it has discovered a number of close-approaching asteroids. Several of these will be examined as case studies. Close approaching or impacting asteroids may have unremarkable digest scores as they approach Earth, which compounds the discovery problem, since they may not be listed on the Near-Earth Object Confirmation Page (NEOCP). The low digest score occurs because the eastward topocentric motion of the observer induces a westward motion of the approaching asteroid which may be similar to the motion of a main-belt asteroid. Asteroids approaching from east of opposition may also have very slow motion during part of their approach, which also hampers discovery. If an approaching asteroid is seen but not listed on the NEOCP, it will not be analyzed by Scout and NEODyS, and will not be followed up. Close approaching or impacting asteroids will usually exhibit curvature in their motion (depending on the approach geometry). Curvature is not a part of the digest score calculation. Objects showing curvature with modest digest scores must be recognized and manually placed on the NEOCP. Astrometric errors can mimic curvature, and produce erroneous alerts, so care is needed in identifying real curvature in the motion of these nearby objects.
We present the communications architecture for the Asteroid Terrestrial-impact Last Alert System (ATLAS) and its suitability as a rapid responder in the global network of NEO detection and tracking. ATLAS is a worldwide system of wide-field telescopes dedicated to searching for hazardous asteroids, especially objects on close-approach or final trajectories. Since its construction in 2015, ATLAS has observed two of the three impacting asteroids detected prior to impact -- 2018 LA and 2019 MO. The system has expanded from a pair of telescopes based in Hawaii to a four-telescope system that can search the entire dark sky from north to south celestial pole every night to a magnitude limit of 19.7 on dark nights.
The ATLAS system is controlled completely by software and is fully robotic -- telescope scheduling and observatory control are fully computer-controlled and data are streamed to Hawaii in real time for image reduction and asteroid processing. The only human participation is the vetting of candidate new near-Earth asteroids (NEOs) that are extracted from the asteroid search. ATLAS data processing excels at measurement of streaked detections and can search for objects close to the Earth with large sky-plane uncertainties. While the ATLAS telescope scheduler normally executes a pre-programmed schedule that rasters a wide declination band, the scheduler is adaptive and can be triggered to inject external requests for targeted followup of asteroids, usually when their sky-plane uncertainties are large. This capability is already in use internally and with selected external observers. The combination of existing robotic infrastructure, adaptive scheduling, and automatic data reductions means that ATLAS can be both a producer of alerts for dangerous objects and a receiver that can assist in astrometric followup.
Over the past few years ESA's Planetary Defence Office has developed a network of small to medium sized telescopes with nearly-global coverage. This network is composed by ESA-owned and operated telescopes, but also by external facilities to which our team has access via dedicated contracts, scientific collaborations, institutional agreements or traditional proposals.
The goal of such network is to provide rapid response capabilities to react to urgent follow-up observation needs, such as those imposed by imminent impactors or very close Earth fly-bys.
In this presentation we will briefly discuss how we are using such a network, and present the outcome of dedicated observing campaigns and challenging observations we performed.
We will also briefly discuss how recent advances in imaging techniques (such as CMOS sensors), hardware (GPUs) and software (synthetic tracking) capabilities have significantly improved the capabilities of small aperture instruments to obtain high quality astrometry of faint objects.
The recent case of 2022 EB5 also gives us the opportunity to discuss some of the challenges that become apparent when extracting astrometry from fast-moving targets. These span from trailing issues to timing or geographical coordinates inaccuracies, which may introduce significant biases in the astrometry and in any impact prediction derived from such measurements.
One of the major goals of ESA’s Planetary Defence Office is to discover Near-Earth Objects (NEOs) imminently before impact. Currently existing survey telescopes include ATLAS, Pan-STARRS and Catalina are contributing to a large number of new NEO discoveries each year, but to date, only five NEOs have been discovered before impact.
We present simulations carried out using a theoretical population of imminent impactors to assess the capability of surveys to detect them. For existing surveys, past pointings are taken from the Minor Planet Center’s database, while for the upcoming surveys using Vera Rubin Observatory and the Flyeye Telescopes, pointings are generated based on their planned strategies.
The results include the number of imminent impactors each survey would detect, and with how many days of warning. The simulation is used to give an indication of the ideal location for the Flyeye Telescopes, by finding the place where the detection rate is maximised. The effect of the observations from the Vera Rubin Observatory on the Flyeye survey is discussed.
Catalina Sky Survey (CSS) has discovered three of the five imminent impactors detected to date. While the principal focus of CSS and other contemporary near-Earth object (NEO) surveys is to discover unknown larger members of the NEO population, CSS has demonstrated sensitivity to some smaller, nearby objects including imminent impactors during certain phases of their final approach. I will present some attributes of CSS’s instrumentation, survey design and operations that improve the chances of detecting and alerting on small NEOs prior to Earth impact.
Initial detection of an imminent impactor is only the first step in its discovery. The NEO-observing community should quickly be alerted to the impact, to determine the precise time and place of impact, to understand and communicate any hazards, and to maximize the scientific return of a predicted impact event. To assist with follow-up planning, CSS has recently deployed a tool for NEO observers called NEOfixer. NEOfixer aims to optimally improve the NEO catalog by providing instrument-specific prioritized lists of targets to observers, guided by planetary defense concerns. NEOfixer weights object importance and confidence alongside observational cost, benefit, and urgency. Coordination across multiple follow-up sites is facilitated by ingesting targeting information and observation status from participating observatories, and adjusting stations’ priority scores in real-time. NEOfixer also provides a method for measuring the benefit of any and all NEO observations. I will discuss how NEOfixer can encourage and coordinate observations of the next imminent impactor, and will present preliminary results outlining NEOfixer’s assessment of historical observation benefit.
Survey systems and telescopes are of paramount importance in the discovery of imminent impactors. State of the art and future additions to the network of telescopes will be portrait in this session.
The Rubin Observatory is a new U.S. NSF/DOE-funded facility on Cerro Pachón, Chile, housing the 8.4m Simonyi Survey Telescope. The Observatory is in the final stage of construction, expected to achieve first light and enter commissioning in September 2023. Over a ten-year period Rubin will execute the Legacy Survey of Space and Time (LSST). Enabled by its 9.6 square degree field of view, a 3.2 Gigapixel camera, and a cadence covering the sky every 3-4 days to single-exposure depths of r~24mag, the LSST will deliver the largest catalog of Solar System objects to date. Based on simulations, the catalog will include 5M+ new main-belt asteroids, 100,000+ NEAs, 200,000+ Jupiter Trojans, 40,000+ TNOs, and tens of ISOs (among others).
A number of these objects will be very nearby. Existing simulations (using the S3M model and thus very incomplete at small sizes) show Rubin will detect hundreds of objects within a ~lunar distance. Simplistic but informative extrapolations based on comparisons with present-day survey indicate Rubin is likely to discover a number of imminent impactors as well: on order of one per year or more.
This talk will open with a brief status summary and projections for Rubin's Solar System science yields, and then discuss possibilities for imminent impactors. Two most interesting applications are detection of small objects days before impact, but also the ability to rapidly provide precovery observations for objects discovered by other observatories. With operations less than two years away, it's an excellent time to understand how Rubin can contribute to imminent impactor detection and alerting.
Survey systems and telescopes are of paramount importance in the discovery of imminent impactors. State of the art and future additions to the network of telescopes will be portrait in this session.
Whenever enough time is available for the impact to occur, satellites could be operated to retrieve observations of the atmospheric event. This session is foreseen to present current satellite capabilities which could be employed for these observations.
The Meteosat Third Generation Lightning Imager (MTG LI) will perform the geostationary detection of lightning optical emissions from space. Such radiation is produced by electric discharges within or below a cloud and reaches the cloud top after multiple scattering. The LI is designed to sense this cloud-top emission within a 1.9 nm wide band centred on 777.4 nm, with a 4.5 km resolution at sub-satellite point (located at [lat, lon] = [0, 0] deg) and 1 kHz acquisition frequency. LI will enable the continuous monitoring of lightning activity within a field-of-view which covers about 84% of the Earth disk observable from geostationary orbit.
Geostationary lightning imagers, as the Geostationary Lightning Mapper (GLM) aboard GOES satellites, have demonstrated the capability of detecting optical emissions (fireballs) from meteors/bolides entering the Earth atmosphere. In fact, Level 2 data from three different instruments, i.e., GLM-16, 17, 18, are being analysed to individuate, characterize, and interpret “light curves” of fireballs. MTG LI is expected to have lightning detection performances in line with GLMs. For this reason, it is reasonable to expect LI data to contain such “light curves”.
I this contribution, we aim at presenting:
• the MTG Programme,
• the LI instrument key design features,
• the LI lightning detection technique,
• the LI data processing, and
• strengths of LI Level 1b products for the systematic investigation of fireball events.
The Geostationary Lightning Mapper (GLM) instrument onboard the GOES 16 and 17 satellites has been shown to be capable of detecting bolides in the atmosphere. Due to its large, continuous field of view and immediate public data availability, GLM provides a unique opportunity to detect a large variety of bolides, including those in the 0.1 to 3 m diameter range that complements current ground-based bolide detection systems, which are typically sensitive to smaller objects. We have deployed a machine learning based bolide detection and light curve generation pipeline with detections being promptly published on a NASA hosted publicly available website, https://neo-bolide.ndc.nasa.gov. An interactive data visualizer is also available at https://bolides.seti.org. The goal is to generate a large catalog of calibrated bolide light curves to provide an unprecedented data set for three purposes: 1) to inform meteor entry models on how incoming bodies interact with the atmosphere, 2) to infer the pre-entry properties of the impacting bodies and 3) to statistically analyze bolide impact populations across the globe. The pipeline has now been operational for over 3 years and we have amassed a catalogue of over 4000 bolides. We present a statistical analysis of the bolides detected, how our bolide database can be used to study bolide impacts and how it can aid the planetary defense community.
NASA’s Planetary Defense Coordination Office (PDCO) was established to manage NASA’s planetary defense-related projects and coordinate activities across multiple U.S. agencies (along with international efforts) to plan appropriate responses to the potential asteroid impact hazard. PDCO currently funds four ground-based survey capabilities (and re-purposed astrophysics survey instrument in low-Earth orbit). These survey efforts are increasingly detecting close encounter events (i.e., < 0.001 AU) and have enabled prediction of some small object impact events.
PDCO also partners with several other U.S. government agencies, most notably the Federal Emergency Management Agency (FEMA), to better assess the various challenges associated with a planetary defense response, to include exercising protocols as defined in the National Near-Earth Object (NEO) Preparedness Strategy and Action Plan and the Near-Earth Object Impact Threat Emergency Protocols (NITEP) documents. The 4th Planetary Defense Tabletop Exercise (TTX4) was the first time State and local emergency managers participated on a large scale.
NASA will provide an overview of the Planetary Defense Coordination Office (PDCO) whose mission is:
• Finding and tracking near-Earth objects (NEOs) that pose a hazard of impacting Earth.
• Characterizing NEOs to determine trajectory, size, shape, mass, composition, rotational dynamics, and other parameters to assess the likelihood and severity of a potential Earth impact.
• Providing alerts and warning of timing and potential effects and determine possible means to mitigate the impact.
• Lead planning and implementation of measures to deflect or disrupt (break up) an object on an impact course with Earth, or to mitigate the effects of an impact if it cannot be prevented.
• Supporting terrestrial mitigation measures that can be taken to protect lives and property such as evacuation and movement of critical infrastructure.
Only a handful of proxy strength measures are available for decameter and smaller NEAs. One data source which can address the question of meter-sized NEO structural strength is the recent release of over 800 light curves for bolides detected by US Government sensors since 1988. A subset of these events (about 270) also have trajectory, speed and height at peak brightness information. These data, together with the recently available lightcurves, afford the possibility of applying ablation modelling to infer strength based on fragmentation heights. Among these 270 bolides with photometric and metric information, we found a dozen events which stood out from the rest of the population in that they reached peak brightness at very high altitudes (>50 km) and had very low entry speeds. Among these dozen, two were clearly on cometary-type orbits, while the remainder were on asteroidal orbits. Of the asteroidal bodies, all showed global strengths of order ~100 kPa or lower. Here we report on ablation modelling to assess the potential structural makeup of these bodies together with their potential escape regions from the main belt based on current orbits. Our modelling suggests these meteoroids are very weak and potentially rubble pile structures. They comprise ~5% of all meter-sized Earth impactors detected by the USG sensors.
Whenever enough time is available for the impact to occur, satellites could be operated to retrieve observations of the atmospheric event. This session is foreseen to present current satellite capabilities which could be employed for these observations.
Fireball networks could be warned of imminent impacts such to allow special attention to the atmospheric phase of such events. Presentations and discussion in this session shall target how the information could be used by fireball networks and in which manner they could be triggered.
Since 2005, the AMS (American Meteor Society) has operated an online fireball program that to date has logged over 280,000 witness reports and more than 35,000 confirmed fireball events. The AMS online fireball report form was specifically designed for use by people with no astronomy experience who witnessed a fireball, a bolide or a suspected similar phenomenon. In 2013 the AMS extended the program with the IMO (International Meteor Organization) and with members help, the online fireball report form was translated into more than 32 languages. The application not only allows the witnesses to share the details of their sightings (location, direction, duration, etc.) but also to upload photos and/or videos of the events. These media are often used to overcome the lack of precision of the witness data and their inability to determine the velocity of the fireball events. They are also tremendous assets for meteorite recovery when no meteor camera network caught the event. The AMS Fireball program has documented numerous meteorite falls and helped lead to over 15 meteorite recoveries in the United States. In 2018, the program helped produce the ground track used for the recovery of a meteorite in Botswana from the asteroid 2018 LA. The AMS Fireball Program is now being further extended with the ALLSKY7 multi-camera device and network. These organizations, websites and devices along with a world-wide community provide a technical ecosystem designed for and dedicated to fireball study and meteorite recovery.
The AllSky7 Fireball Network is a global, amateur-driven camera network to record the full sky 24/7. It was initiated by Mike Hankey in 2018 and consists meanwhile of a number of local networks in different regions of the world. With about 90 stations, the European AllSky7 network is the biggest and most dense installation to date. We aim at an average distance of 100 to 150 km between stations, which has meanwhile been reached in Germany, Hungary and BeNeLux. Such a camera density ensures best geometry for every recorded fireball. Almost every meteor recorded by our network is a multi-station detection, and in certain cases we have recorded fireballs from up to 30 stations in parallel. The network is growing steadily, and both the hardware design and the software suite are further developed. Recently we introduced AllSky7+ cameras, which integrate a fisheye camera for better recording of particularly bright fireballs, and mobile camera editions. The software pipeline has been upgraded with AI capabilities to improve the detection accuracy for meteors and other events.
Prime target of the Allsky7 network is the observation of meteors, fireballs, and meteorite droppers, but it has the potential to record many other atmospheric phenomena. We have been successfully recording daylight fireballs, aurorae, noctilucent clouds, red sprites, satellite re-entries and other rare events. Even though the network is primarily driven by amateur astronomers, we have a number of planetariums, observatories, universities, research institutes and museums as camera owners. A number of sub-projects have been spawned or planned, which strengthen the ties between amateur astronomy, public outreach and professional research.
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) was adopted by the United Nations General Assembly on 10 September 1996 to prohibit nuclear explosions. Twenty-five years later, the CTBT enjoys near universality, however it has not yet entered into force. In the meantime, the Preparatory Commission (PrepCom) for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is responsible for promoting the CTBT and establishing a verification regime to ensure compliance with the CTBT. The International Data Centre (IDC) of the CTBTO PrepCom receives and processes in near real-time data from the International Monitoring System (IMS), a globally distributed network of seismic, hydroacoustic, infrasound and radionuclide stations. Once completed, the IMS network will comprise 337 facilities including 60 infrasound stations. As of mid-2022, 53 have been installed and are sending data to the IDC. The infrasound stations are arrays of measurement systems are sensitive to low-frequency [0.02 – 4 Hz] acoustic pressure variations in the atmosphere. Once received, stored and referenced in IDC database, the station data are automatically processed. This action then leads to the network processing stage to constructs seismic, hydro-acoustic and infrasound events reported in IDC products, such as final waveform product the Reviewed Event Bulletin (REB). During provisional operations, the target timeline for REB publication is within 10 days of real time.
For infrasound technology, specialized software has been developed for every IDC processing stage, which allow to detect infrasound signals, categorize and identify relevant detections, form automatic events and perform interactive review analysis. Since 2010, tens of thousands of waveform events containing infrasound associations appear in IDC bulletins. This demonstrates the sensitivity of the IMS infrasound component and IDC ability to monitor the infrasound activity at the global scale. The unique information gathered by the IMS systems have been widely used for civil and scientific studies and related to atmospheric impacts of NEO such as the Chelyabinsk meteor in February 2013, the Bering Sea fireball on 18 December 2018 or the atmospheric airburst over the Southern Atlantic Ocean on 7 February 2022. Other significant events registered with infrasound technology are powerful volcanic eruptions, controlled explosions, or announced underground nuclear tests. Infrasound technology remains an active research field on atmospheric dynamics, on characterizing the infrasound global wavefield, or on gravity waves study that could lead to deriving a space and time varying gravity wave climatology.
The NEar real-time MOnitoring System, NEMO, aims to collect and provide information on bright fireballs from objects entering Earth´s atmosphere from space. It was developed at the University of Oldenburg, Germany, and then handed over to ESA where it is currently being operated. One of the main objectives of NEMO is to provide information in near real-time on fireball events which caused public attention. Social media and other sources are searched automatically for reports of fireballs. Credible events are then listed and recorded. In a second step, for events which are very bright or of special interest for other reasons additional information is collected. Examples are information on the trajectory, detection of related infrasound signals, estimations of the size and impact energy and if meteorites have been found.
Additional developments are ongoing and planned. These include a notification system to inform observation networks on events and a more automatic system to identify re-entering objects. At present NEMO collects data on past events only. NEMO seems perfectly suited to also provide predictions of coming fireball events. Re-entering space debris is one candidate and imminent impactors are another. Predictions of atmospheric impacts and fireballs would largely increase the public and scientific interest in such events. It would also enhance the credibility of the prediction capabilities of the NEO field.
The planned NEMO notification system could be used to spread the information on potential imminent impacts. In addition, information on the object before impact will largely improve the analysis of a resulting fireball and also serve as calibration for other events. Of course, predictions can have large uncertainties. It will have to be discussed at what level of confidence impact predictions will be published.
Fireball networks could be warned of imminent impacts such to allow special attention to the atmospheric phase of such events. Presentations and discussion in this session shall target how the information could be used by fireball networks and in which manner they could be triggered.
At this point of the workshop, inputs from all main stakeholders will be available from the previous sessions. The aim of this session is to have a broad open discussion on how we could set up a network to increase the coordination and observation of these events. Furthermore, discussion would be initiated to establish a alert system for this.