2023
Journal article
Open Access
The short-term effects of the Cosmos 1408 fragmentation on neighboring inhabited space stations and large constellations
Pardini C., Anselmo L.
In terms of cataloged debris produced, the anti-satellite test carried out by Russia, in November 2021, at an altitude of about 480 km, leading to the destruction of the old satellite Cosmos 1408, was the second worst to date and represented the third worst fragmentation in orbit. It generated more than 1/4 of the cataloged debris produced over 55 years by all such tests and almost twice as many as were produced by all previous Soviet tests. After placing this event in its historical context, this paper analyzes in detail how the evolution of the Cosmos 1408 debris cloud affected the environment below 600 km in the first seven months, focusing on the two operational space stations and the Starlink large constellation of satellites. During the first six months following the test, the Cosmos 1408 cloud of fragments nearly doubled the average flux of cataloged objects on the International Space Station and increased by about 3/4 that on China's Tiangong. In the same period, the Starlink large constellation saw an average increase in the flux of cataloged objects of about 20%. Some orbital planes, the "counter-rotating" ones with respect to the Cosmos 1408 debris cloud, were more affected than others, and the affected planes gradually changed over time, due to the differential precession of cloud and constellation nodes. However, being the Starlink constellation 70 km higher up, the flux of Cosmos 1408 cataloged debris steadily decreased over the period analyzed, due to the cloud orbital decay, reducing to just over a quarter of its extrapolated initial value after seven months.Source: Acta astronautica (2023). doi:10.1016/j.actaastro.2023.02.043
DOI: 10.1016/j.actaastro.2023.02.043
Metrics:
Pardini C., Anselmo L.
In terms of cataloged debris produced, the anti-satellite test carried out by Russia, in November 2021, at an altitude of about 480 km, leading to the destruction of the old satellite Cosmos 1408, was the second worst to date and represented the third worst fragmentation in orbit. It generated more than 1/4 of the cataloged debris produced over 55 years by all such tests and almost twice as many as were produced by all previous Soviet tests. After placing this event in its historical context, this paper analyzes in detail how the evolution of the Cosmos 1408 debris cloud affected the environment below 600 km in the first seven months, focusing on the two operational space stations and the Starlink large constellation of satellites. During the first six months following the test, the Cosmos 1408 cloud of fragments nearly doubled the average flux of cataloged objects on the International Space Station and increased by about 3/4 that on China's Tiangong. In the same period, the Starlink large constellation saw an average increase in the flux of cataloged objects of about 20%. Some orbital planes, the "counter-rotating" ones with respect to the Cosmos 1408 debris cloud, were more affected than others, and the affected planes gradually changed over time, due to the differential precession of cloud and constellation nodes. However, being the Starlink constellation 70 km higher up, the flux of Cosmos 1408 cataloged debris steadily decreased over the period analyzed, due to the cloud orbital decay, reducing to just over a quarter of its extrapolated initial value after seven months.Source: Acta astronautica (2023). doi:10.1016/j.actaastro.2023.02.043
DOI: 10.1016/j.actaastro.2023.02.043
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2023
Conference article
Open Access
On the need to assess and mitigate the risk from uncontrolled re-entries of artificial space objects in view of the current and future developments in space activities
Pardini C., Anselmo L.
From 1 January 2010 to 24 August 2023, 566 orbital stages and 511 spacecraft with a radar cross section > 1 m2 have re-entered without control the Earth's atmosphere. The total returned mass was 1650 metric tons, corresponding to a mean of 115 metric tons per year. 77% of the mass belonged to orbital stages, 23% to spacecraft. The uncontrolled re-entries of orbital stages are currently dominated by China, accounting for more than half of the decaying mass, while for spacecraft 2/3 of the mass belongs to American satellites. 60% of the re-entries occurred within 2 years of the launch. The ground casualty expectancy due to orbital stages was always predominant over that from spacecraft, by an average factor of nearly three. From 2010 to 2018, the total casualty probability remained substantially stable, with a mean annual value just over 1%. Since 2019, instead, the annual casualty probability of both spacecraft and orbital stages progressively increased, reaching a total value of around 3% in 2022 and 2023 (extrapolated). Even assuming a stable launch activity, in the coming years, when many of the recently launched spacecraft will start to re-enter, the casualty expectancy of orbital stages will remain basically the same, while that of spacecraft might progressively increase by a factor of 20. This would lead to an annual casualty probability of about 20%, even more in case of a further growth in launch activity, very likely based on current forecasts. The quick implementation of widespread and effective mitigation measures, like controlled de-orbiting and design for demise, is therefore necessary, to prevent the situation from deteriorating too much.Source: IAC 2023 - 74th International Astronautical Congress, Baku, Azerbaijan, 2-6/10/2023
Pardini C., Anselmo L.
From 1 January 2010 to 24 August 2023, 566 orbital stages and 511 spacecraft with a radar cross section > 1 m2 have re-entered without control the Earth's atmosphere. The total returned mass was 1650 metric tons, corresponding to a mean of 115 metric tons per year. 77% of the mass belonged to orbital stages, 23% to spacecraft. The uncontrolled re-entries of orbital stages are currently dominated by China, accounting for more than half of the decaying mass, while for spacecraft 2/3 of the mass belongs to American satellites. 60% of the re-entries occurred within 2 years of the launch. The ground casualty expectancy due to orbital stages was always predominant over that from spacecraft, by an average factor of nearly three. From 2010 to 2018, the total casualty probability remained substantially stable, with a mean annual value just over 1%. Since 2019, instead, the annual casualty probability of both spacecraft and orbital stages progressively increased, reaching a total value of around 3% in 2022 and 2023 (extrapolated). Even assuming a stable launch activity, in the coming years, when many of the recently launched spacecraft will start to re-enter, the casualty expectancy of orbital stages will remain basically the same, while that of spacecraft might progressively increase by a factor of 20. This would lead to an annual casualty probability of about 20%, even more in case of a further growth in launch activity, very likely based on current forecasts. The quick implementation of widespread and effective mitigation measures, like controlled de-orbiting and design for demise, is therefore necessary, to prevent the situation from deteriorating too much.Source: IAC 2023 - 74th International Astronautical Congress, Baku, Azerbaijan, 2-6/10/2023
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2023
Report
Restricted
Disposal of high inclination geosynchronous spacecraft and orbital stages
Anselmo L.
At the end of its 35th meeting in Darmstadt, in 2017, the WG4 proposed - at the request of CNES - a new AI on Disposal of High Inclination Geosynchronous Spacecraft and Orbital Stages. The SG discussed the proposal at the intermediate meeting held in Adelaide during the IAC-2017 conference. There, several delegations asked for changes and further clarifications. At the 36th IADC plenary meeting, held in Tsukuba in 2018, ASI made two technical presentations addressing the class of objects in geosynchronous orbits for which the IADC re-orbiting formula is not able to prevent the later crossing of the GEO protected region. After the meeting, the WG4 modified the wording and resubmitted the AI to the SG on 13 September 2018. It was discussed at the SG intermediate meeting held in Bremen during the IAC-2018 conference (3 October 2018), but no decision was taken. On 10 December 2018, the SG approved the proposal as AI 36.3, stressing that «updating guidelines should not be a direct output of the action item». As part of the wrap-up work on AI 32.1 Update of the IADC Space Debris Mitigation Guidelines and of the Support Document (On-ground Casualty Expectation and Max Long Term Presence in GEO) during 2020 and early 2021, it was noted that there are similarities between the long-term presence of spacecraft and upper stages on orbits crossing the GEO protected region. Such crossing orbits include (super-)GTO's as well as highly eccentric orbits. Noting that also AI 22.2 failed to find consensus on the topic of limiting the long-term presence in GEO, the lessons learned are put in context in this report as well.Source: IADC-23-02, 2023
Anselmo L.
At the end of its 35th meeting in Darmstadt, in 2017, the WG4 proposed - at the request of CNES - a new AI on Disposal of High Inclination Geosynchronous Spacecraft and Orbital Stages. The SG discussed the proposal at the intermediate meeting held in Adelaide during the IAC-2017 conference. There, several delegations asked for changes and further clarifications. At the 36th IADC plenary meeting, held in Tsukuba in 2018, ASI made two technical presentations addressing the class of objects in geosynchronous orbits for which the IADC re-orbiting formula is not able to prevent the later crossing of the GEO protected region. After the meeting, the WG4 modified the wording and resubmitted the AI to the SG on 13 September 2018. It was discussed at the SG intermediate meeting held in Bremen during the IAC-2018 conference (3 October 2018), but no decision was taken. On 10 December 2018, the SG approved the proposal as AI 36.3, stressing that «updating guidelines should not be a direct output of the action item». As part of the wrap-up work on AI 32.1 Update of the IADC Space Debris Mitigation Guidelines and of the Support Document (On-ground Casualty Expectation and Max Long Term Presence in GEO) during 2020 and early 2021, it was noted that there are similarities between the long-term presence of spacecraft and upper stages on orbits crossing the GEO protected region. Such crossing orbits include (super-)GTO's as well as highly eccentric orbits. Noting that also AI 22.2 failed to find consensus on the topic of limiting the long-term presence in GEO, the lessons learned are put in context in this report as well.Source: IADC-23-02, 2023
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2023
Report
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Accordo di collaborazione tra ASI e INAF N. 2020-6-HH.0, Deliverable Document RF_2019-2021 - Detriti spaziali supporto alle attività IADC e SST 2019-2021
Bianchi G., Teofilatto P., Piergentili F., Valentini G., Buzzoni A., Di Lizia P., Colombo C., Rossi A., Pardini C., Francesconi A., Anselmo L.
Questo documento è l'ultimo deliverable dell'accordo di collaborazione tra ASI e INAF in ambito "Detriti Spaziali- Supporto alle attività IADC e SST 2019-2021". Sono riportate le attività svolte, dai vari enti coinvolti, dal M31 al M38, suddivisi per WP (Work Package).Source: ISTI Project Report, Accordo ASI-INAF n. 2020-6-HH.0, RF_2019-2021, 2023
Bianchi G., Teofilatto P., Piergentili F., Valentini G., Buzzoni A., Di Lizia P., Colombo C., Rossi A., Pardini C., Francesconi A., Anselmo L.
Questo documento è l'ultimo deliverable dell'accordo di collaborazione tra ASI e INAF in ambito "Detriti Spaziali- Supporto alle attività IADC e SST 2019-2021". Sono riportate le attività svolte, dai vari enti coinvolti, dal M31 al M38, suddivisi per WP (Work Package).Source: ISTI Project Report, Accordo ASI-INAF n. 2020-6-HH.0, RF_2019-2021, 2023
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2023
Contribution to conference
Restricted
Uncontrolled re-entries: the need to mitigate the increasing risk on ground due to the re-entry of large spacecraft and orbital stages, and to establish an aggregate re-entry risk for constellations
Pardini C., Anselmo L.
The casualty probability associated with the uncontrolled re-entry of spacecraft is still quite low, of the order of 0.8% in 2022, but the disposal of satellites from the current planned mega-constellations could significantly increase the likelihood of casualties on the ground in the coming years. In fact, even if the value of the casualty expectancy associated with each satellite of a constellation is below the alert threshold of 10-4, if several thousands more satellites were to re-enter without control every year, the casualty probability would probably reach unacceptable values for safety on the ground and in the airspace. Therefore, it would be necessary to establish an aggregate re-entry risk for constellations, by adopting, for instance, an annual limit for the casualty expectancy value that the constellation shall not exceed.Source: 41st Plenary Meeting of the Inter-Agency Space Debris Coordination Committee (IADC), Darmstadt, Germany, 12-15/06/2023
Pardini C., Anselmo L.
The casualty probability associated with the uncontrolled re-entry of spacecraft is still quite low, of the order of 0.8% in 2022, but the disposal of satellites from the current planned mega-constellations could significantly increase the likelihood of casualties on the ground in the coming years. In fact, even if the value of the casualty expectancy associated with each satellite of a constellation is below the alert threshold of 10-4, if several thousands more satellites were to re-enter without control every year, the casualty probability would probably reach unacceptable values for safety on the ground and in the airspace. Therefore, it would be necessary to establish an aggregate re-entry risk for constellations, by adopting, for instance, an annual limit for the casualty expectancy value that the constellation shall not exceed.Source: 41st Plenary Meeting of the Inter-Agency Space Debris Coordination Committee (IADC), Darmstadt, Germany, 12-15/06/2023
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2023
Contribution to conference
Restricted
Italian Space Agency space debris mitigation activities - Delegation report
Vellutini E., Anselmo L.
Statistics from IADC-40 (Oct 2022) to IADC-41 (Jun 2023).Source: 41st Plenary Meeting of the Inter-Agency Space Debris Coordination Committee (IADC), Darmstadt, Germany, 12-15/06/2023
Vellutini E., Anselmo L.
Statistics from IADC-40 (Oct 2022) to IADC-41 (Jun 2023).Source: 41st Plenary Meeting of the Inter-Agency Space Debris Coordination Committee (IADC), Darmstadt, Germany, 12-15/06/2023
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2023
Conference article
Unknown
The risk of casualties from the uncontrolled re-entry of spacecraft and orbital stages
Pardini C., Anselmo L.
From the beginning of 2010 to the end of 2022, 951 intact objects (spacecraft and orbital stages) with a radar cross-section greater than one square meter re-entered the Earth's atmosphere uncontrolled. The total returned mass was about 1500 metric tons, with a mean of 116 metric tons per year, mostly concentrated (80%) in orbital stages. On average, objects with a mass greater than 500 kg re-entered every 8 days, those exceeding 2000 kg every 2 weeks, and those above 5000 kg around 3 times per year. Only 4% of the re-entries came from orbits with an eccentricity greater than 0.1, while 41% were from nearly circular orbits with eccentricity lower than 0.001. 52% of the re-entries occurred in the northern hemisphere and 48% in the southern one. The areas of the planet most affected where those between 30 deg and 60 deg north. However, excluding the polar regions, the re-entry flux per unit area was relatively uniform, from 60° south to 60° north, implying a ground casualty risk manly driven by the population density. 84% of orbital stages and 19% of spacecraft exceeded a casualty expectancy of 10-4, the ceiling recommended by several guidelines and standards worldwide. The total ground casualty expectancy over the 13 years analyzed was estimated to be 0.194, corresponding to a probability of injuring or killing at least one person of about 18%. After remaining relatively stable from 2010 to 2018, the casualty expectancy and probability have grown systematically from then on, leading in 2022 to a chance of casualty of 2.9%, with orbital stages and spacecraft contributing, respectively, 72% and 28%.Source: 12th IAASS International Space Safety Conference "Making Space Travel Safer", pp. 13–23, Osaka, Japan, 22-24/05/2023
Pardini C., Anselmo L.
From the beginning of 2010 to the end of 2022, 951 intact objects (spacecraft and orbital stages) with a radar cross-section greater than one square meter re-entered the Earth's atmosphere uncontrolled. The total returned mass was about 1500 metric tons, with a mean of 116 metric tons per year, mostly concentrated (80%) in orbital stages. On average, objects with a mass greater than 500 kg re-entered every 8 days, those exceeding 2000 kg every 2 weeks, and those above 5000 kg around 3 times per year. Only 4% of the re-entries came from orbits with an eccentricity greater than 0.1, while 41% were from nearly circular orbits with eccentricity lower than 0.001. 52% of the re-entries occurred in the northern hemisphere and 48% in the southern one. The areas of the planet most affected where those between 30 deg and 60 deg north. However, excluding the polar regions, the re-entry flux per unit area was relatively uniform, from 60° south to 60° north, implying a ground casualty risk manly driven by the population density. 84% of orbital stages and 19% of spacecraft exceeded a casualty expectancy of 10-4, the ceiling recommended by several guidelines and standards worldwide. The total ground casualty expectancy over the 13 years analyzed was estimated to be 0.194, corresponding to a probability of injuring or killing at least one person of about 18%. After remaining relatively stable from 2010 to 2018, the casualty expectancy and probability have grown systematically from then on, leading in 2022 to a chance of casualty of 2.9%, with orbital stages and spacecraft contributing, respectively, 72% and 28%.Source: 12th IAASS International Space Safety Conference "Making Space Travel Safer", pp. 13–23, Osaka, Japan, 22-24/05/2023
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2023
Contribution to conference
Unknown
METRIC: a mission concept for upper atmosphere mapping, gravitational physics and geodesy
Peron R., Lorenzini E. C., Anselmo L., Bassan M., Bianco G., Dell'Agnello S., Iafolla V., Lefevre C., Lucchesi D. M., Lucente M., Magnafico C., Muccino M., Negusini M., Pardini C., Porcelli L., Santoli F., Tornatore V., Valmorbida A., Vecchiato A., Vespe F.
We describe here a mission concept - called METRIC (Measurement of EnvironmenTal and Relativistic In-orbit preCessions) - for a spacecraft to be placed in a low Earth orbit, with dedicated instrumentation to provide data useful for atmospheric science, fundamental physics and geodesy. The main scientific objectives are: map the atmospheric density by in-situ acceleration measurement and by spacecraft tracking at altitudes of great interest for satellites deorbiting; perform fundamental physics tests through a precise orbit determination and verification of the equation of motion for a well-characterized test mass; provide an additional, space-based, node to improve the tie among different space geodesy techniques. These three areas being distinct but strongly interrelated in the case of Earth System science, it appears that they can benefit from the availability of a well-calibrated space-based platform such as the one being proposed. Following a discussion of the scientific objectives, the mission idea will be described with a baseline for spacecraft configuration, scientific instruments and data analysis strategies.Source: XXV SIGRAV Conference on General Relativity and Gravitation, Trieste, Italy, 4-8/09/2023
Peron R., Lorenzini E. C., Anselmo L., Bassan M., Bianco G., Dell'Agnello S., Iafolla V., Lefevre C., Lucchesi D. M., Lucente M., Magnafico C., Muccino M., Negusini M., Pardini C., Porcelli L., Santoli F., Tornatore V., Valmorbida A., Vecchiato A., Vespe F.
We describe here a mission concept - called METRIC (Measurement of EnvironmenTal and Relativistic In-orbit preCessions) - for a spacecraft to be placed in a low Earth orbit, with dedicated instrumentation to provide data useful for atmospheric science, fundamental physics and geodesy. The main scientific objectives are: map the atmospheric density by in-situ acceleration measurement and by spacecraft tracking at altitudes of great interest for satellites deorbiting; perform fundamental physics tests through a precise orbit determination and verification of the equation of motion for a well-characterized test mass; provide an additional, space-based, node to improve the tie among different space geodesy techniques. These three areas being distinct but strongly interrelated in the case of Earth System science, it appears that they can benefit from the availability of a well-calibrated space-based platform such as the one being proposed. Following a discussion of the scientific objectives, the mission idea will be described with a baseline for spacecraft configuration, scientific instruments and data analysis strategies.Source: XXV SIGRAV Conference on General Relativity and Gravitation, Trieste, Italy, 4-8/09/2023
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2022
Journal article
Open Access
Effects of the deployment and disposal of mega-constellations on human spaceflight operations in low LEO
Pardini C., Anselmo L.
The substantial space traffic changes occurred since the 2010s are having measurable repercussions even at the altitudes used for human spaceflight. These changes were mainly driven by the deployment of thousands of small satellites and cubesats below 600 km. After having evaluated how the situation evolved, from 2008 to 2021, at the altitudes of the International and Chinese space stations, and discussed the main aspects of the problem that may have an operational impact, the attention was focused on what might be expected in the 2020s, whether the current deployment plans for mega-constellations will be realized in whole or in part. Finally, the rationale for the introduction of a "human spaceflight protected region", with the associated space traffic management recommendations, is presented and discussed.Source: Journal of Space Safety Engineering 9 (2022): 274–279. doi:10.1016/j.jsse.2022.03.001
DOI: 10.1016/j.jsse.2022.03.001
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Pardini C., Anselmo L.
The substantial space traffic changes occurred since the 2010s are having measurable repercussions even at the altitudes used for human spaceflight. These changes were mainly driven by the deployment of thousands of small satellites and cubesats below 600 km. After having evaluated how the situation evolved, from 2008 to 2021, at the altitudes of the International and Chinese space stations, and discussed the main aspects of the problem that may have an operational impact, the attention was focused on what might be expected in the 2020s, whether the current deployment plans for mega-constellations will be realized in whole or in part. Finally, the rationale for the introduction of a "human spaceflight protected region", with the associated space traffic management recommendations, is presented and discussed.Source: Journal of Space Safety Engineering 9 (2022): 274–279. doi:10.1016/j.jsse.2022.03.001
DOI: 10.1016/j.jsse.2022.03.001
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2022
Journal article
Open Access
The Kinetic casualty risk of uncontrolled re-entries before and after the transition to small satellites and mega-constellations
Pardini C., Anselmo L.
Over the last 11 years (2010-2020), more than 600 intact objects larger than 1 m^2 have re-entered without control into the Earth's atmosphere. The total returned mass was approximately 1100 t, roughly corresponding to the re-entry of nearly 100 t per year, mostly concentrated (79%) in rocket bodies. Objects with a mass greater than 500 kg re-entered every about 8 days, those exceeding 2000 kg every about 2 weeks and those heavier than 5000 kg one or twice per year. The total casualty expectancy associated with uncontrolled re-entries over the past 11 years was of the order of 1.4 × 10^-1, that in 2020 was almost 1.7 × 10^-2, corresponding to a probability of having had at least one victim of approximately 13% and 2%, respectively. Unlike the alert threshold of 10^-4, linked to single re-entry events, no cumulative risk limit exists for satellite re-entries over one year or more. However, the casualty probability, although still relatively small, cannot be considered negligible, even in view of the launches of mega-constellations planned in the coming years. For instance, if no design for demise was implemented, the addition of 4000 spacecraft re-entering annually would increase the probability of having at least one victim to nearly 30% per year, while 20,000 more satellites would boost it to almost 80%.Source: Journal of Space Safety Engineering 9 (2022): 414–426. doi:10.1016/j.jsse.2022.04.003
DOI: 10.1016/j.jsse.2022.04.003
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Pardini C., Anselmo L.
Over the last 11 years (2010-2020), more than 600 intact objects larger than 1 m^2 have re-entered without control into the Earth's atmosphere. The total returned mass was approximately 1100 t, roughly corresponding to the re-entry of nearly 100 t per year, mostly concentrated (79%) in rocket bodies. Objects with a mass greater than 500 kg re-entered every about 8 days, those exceeding 2000 kg every about 2 weeks and those heavier than 5000 kg one or twice per year. The total casualty expectancy associated with uncontrolled re-entries over the past 11 years was of the order of 1.4 × 10^-1, that in 2020 was almost 1.7 × 10^-2, corresponding to a probability of having had at least one victim of approximately 13% and 2%, respectively. Unlike the alert threshold of 10^-4, linked to single re-entry events, no cumulative risk limit exists for satellite re-entries over one year or more. However, the casualty probability, although still relatively small, cannot be considered negligible, even in view of the launches of mega-constellations planned in the coming years. For instance, if no design for demise was implemented, the addition of 4000 spacecraft re-entering annually would increase the probability of having at least one victim to nearly 30% per year, while 20,000 more satellites would boost it to almost 80%.Source: Journal of Space Safety Engineering 9 (2022): 414–426. doi:10.1016/j.jsse.2022.04.003
DOI: 10.1016/j.jsse.2022.04.003
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2022
Journal article
Open Access
Using the space debris flux to assess the criticality of the environment in low Earth orbit
Pardini C., Anselmo L.
In this paper we introduce a new index for evaluating the likelihood of accidental collisions leading to the complete destruction of intact objects in a volume of space in low Earth orbit (LEO). The proposed index is therefore not intended to assess the criticality of individual objects or missions, but rather to estimate the global impact of space activities on a given region of space. Moreover, the new index has been designed to be objective, as simple as possible, built from easily accessible data, as well as smoothly reproducible by third parties. Named "volumetric collision rate index", it has been developed starting from analytical equations expressing the collision rate as a function of the fluxes of intact objects and cataloged debris pieces. The application of reasonable simplifying assumptions and approximations has finally made it possible to define a dimensionless index that explicitly depends only on the spatial densities of intact objects and cataloged debris pieces. It has therefore been applied to the LEO environment, analyzing its evolution from mid-2008 to mid-2020, a crucial period characterized by an impressive change of space activity patterns, with the launch of lots of small satellites and mega-constellations. We also discuss how the index can be further improved, taking into account the maneuverable satellites, which do not contribute to the collision rate, and the increasing number of cubesats, which in many respects are more similar to debris, finally presenting a preliminary analysis in this direction.Source: Acta astronautica 198 (2022): 756–760. doi:10.1016/j.actaastro.2022.05.045
DOI: 10.1016/j.actaastro.2022.05.045
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Pardini C., Anselmo L.
In this paper we introduce a new index for evaluating the likelihood of accidental collisions leading to the complete destruction of intact objects in a volume of space in low Earth orbit (LEO). The proposed index is therefore not intended to assess the criticality of individual objects or missions, but rather to estimate the global impact of space activities on a given region of space. Moreover, the new index has been designed to be objective, as simple as possible, built from easily accessible data, as well as smoothly reproducible by third parties. Named "volumetric collision rate index", it has been developed starting from analytical equations expressing the collision rate as a function of the fluxes of intact objects and cataloged debris pieces. The application of reasonable simplifying assumptions and approximations has finally made it possible to define a dimensionless index that explicitly depends only on the spatial densities of intact objects and cataloged debris pieces. It has therefore been applied to the LEO environment, analyzing its evolution from mid-2008 to mid-2020, a crucial period characterized by an impressive change of space activity patterns, with the launch of lots of small satellites and mega-constellations. We also discuss how the index can be further improved, taking into account the maneuverable satellites, which do not contribute to the collision rate, and the increasing number of cubesats, which in many respects are more similar to debris, finally presenting a preliminary analysis in this direction.Source: Acta astronautica 198 (2022): 756–760. doi:10.1016/j.actaastro.2022.05.045
DOI: 10.1016/j.actaastro.2022.05.045
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2022
Conference article
Open Access
The short-term impact of the Cosmos 1408 fragmentation on neighboring space regions: from inhabited space stations to large satellite constellations
Pardini C., Anselmo L.
In terms of cataloged debris produced, the anti-satellite test carried out by Russia, in November 2021, at an altitude of about 480 km, leading to the destruction of the old satellite Cosmos 1408, was the second worst to date and represented the third worse fragmentation in orbit. It generated more than 1/4 of the cataloged debris produced over 55 years by all such tests and almost twice as many as were produced by all previous Soviet tests. After placing this event in its historical context, this paper analyzes in detail how the evolution of the Cosmos 1408 debris cloud impacted the environment below 600 km in the first seven months, focusing on the two operational space stations and the Starlink mega-constellation of satellites. For the International Space Station, the Cosmos 1408 cloud of fragments increased the flux of cataloged objects, on average, by nearly 80%, while for the Tiangong Space Station the increase was almost 65%. Immediately after the test, the Starlink mega-constellation saw as well an increase in the flux of cataloged objects, of the order of 20% on average. Some orbital planes, the "counter-rotating" ones with respect to the Cosmos 1408 debris cloud, were more affected than others, and the affected planes gradually changed over time, due to the differential precession of cloud and constellation nodes. However, being the Starlink constellation 70 km higher up, the flux of Cosmos 1408 cataloged debris steadily decreased over the period analyzed, due to the cloud orbital decay, more than halving after seven months.Source: IAC 2022 - 73rd International Astronautical Congress, Paris, France, 18-22/09/2022
Pardini C., Anselmo L.
In terms of cataloged debris produced, the anti-satellite test carried out by Russia, in November 2021, at an altitude of about 480 km, leading to the destruction of the old satellite Cosmos 1408, was the second worst to date and represented the third worse fragmentation in orbit. It generated more than 1/4 of the cataloged debris produced over 55 years by all such tests and almost twice as many as were produced by all previous Soviet tests. After placing this event in its historical context, this paper analyzes in detail how the evolution of the Cosmos 1408 debris cloud impacted the environment below 600 km in the first seven months, focusing on the two operational space stations and the Starlink mega-constellation of satellites. For the International Space Station, the Cosmos 1408 cloud of fragments increased the flux of cataloged objects, on average, by nearly 80%, while for the Tiangong Space Station the increase was almost 65%. Immediately after the test, the Starlink mega-constellation saw as well an increase in the flux of cataloged objects, of the order of 20% on average. Some orbital planes, the "counter-rotating" ones with respect to the Cosmos 1408 debris cloud, were more affected than others, and the affected planes gradually changed over time, due to the differential precession of cloud and constellation nodes. However, being the Starlink constellation 70 km higher up, the flux of Cosmos 1408 cataloged debris steadily decreased over the period analyzed, due to the cloud orbital decay, more than halving after seven months.Source: IAC 2022 - 73rd International Astronautical Congress, Paris, France, 18-22/09/2022
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2022
Conference article
Open Access
Trajectory behavior of high area-to-mass ratio objects in semi-synchronous GPS orbits
Anselmo L., Pardini C.
Following the observational discovery of a significant number of objects characterized both by high eccentricity geosynchronous orbits and by extremely high values of their area-to-mass ratios (A/M), whose origin can probably be traced back to the degradation and detachment of the very light specific mass layers used to protect the surfaces of geostationary spacecraft, a thorough investigation was carried out since 2008 to explore the long-term dynamical evolution of fictitious high A/M objects released, with a negligible Delta-V, in each of the six orbital planes used by Global Positioning System (GPS) satellites. As for the objects observed and studied in near synchronous trajectories, also in this case long lifetime orbits, with mean motions of about 2 revolutions per day, were found possible even for bodies with extremely high A/M. The behavior details, affected by the complex interplay of solar radiation pressure, geopotential and luni-solar resonances, obviously depend on the initial conditions. However, objects with A/M as high as 20-40 m2/kg can avoid orbital decay for at least one century or more, with semi-major axes close to the semi-synchronous values, with maximum eccentricities between 0.3 and 0.7, and with significant orbit pole precessions (faster and wider for increasing values of A/M), leading to inclinations between 30° and more than 90°. For particularly high values of A/M, in fact, the transition from prograde (inclination < 90°) to retrograde (inclination > 90°) motion, and vice versa, would be possible.Source: FAPM-2021 - International Scientific Conference "Fundamental and Applied Problems of Mechanics", pp. 12–15, Moscow, Russia, 7-10/12/2021
DOI: 10.18698/2308-6033-2022-5-2182
Metrics:
Anselmo L., Pardini C.
Following the observational discovery of a significant number of objects characterized both by high eccentricity geosynchronous orbits and by extremely high values of their area-to-mass ratios (A/M), whose origin can probably be traced back to the degradation and detachment of the very light specific mass layers used to protect the surfaces of geostationary spacecraft, a thorough investigation was carried out since 2008 to explore the long-term dynamical evolution of fictitious high A/M objects released, with a negligible Delta-V, in each of the six orbital planes used by Global Positioning System (GPS) satellites. As for the objects observed and studied in near synchronous trajectories, also in this case long lifetime orbits, with mean motions of about 2 revolutions per day, were found possible even for bodies with extremely high A/M. The behavior details, affected by the complex interplay of solar radiation pressure, geopotential and luni-solar resonances, obviously depend on the initial conditions. However, objects with A/M as high as 20-40 m2/kg can avoid orbital decay for at least one century or more, with semi-major axes close to the semi-synchronous values, with maximum eccentricities between 0.3 and 0.7, and with significant orbit pole precessions (faster and wider for increasing values of A/M), leading to inclinations between 30° and more than 90°. For particularly high values of A/M, in fact, the transition from prograde (inclination < 90°) to retrograde (inclination > 90°) motion, and vice versa, would be possible.Source: FAPM-2021 - International Scientific Conference "Fundamental and Applied Problems of Mechanics", pp. 12–15, Moscow, Russia, 7-10/12/2021
DOI: 10.18698/2308-6033-2022-5-2182
Metrics:
See at:
engjournal.ru | ISTI Repository | CNR ExploRA
2022
Report
Unknown
Accordo di collaborazione tra ASI e INAF N. 2020-6-HH.0, Deliverable Document RT2_2019-2021- Detriti spaziali supporto alle attività IADC e SST 2019-2021
Bianchi G., Teofilatto P., Piergentili F., Valentini G., Buzzoni A., Di Lizia P., Colombo C., Rossi A., Pardini C., Francesconi A., Anselmo L.
Questo documento è il terzo deliverable dell'accordo di collaborazione tra ASI e INAF in ambito "Detriti Spaziali- Supporto alle attività IADC e SST 2019-2021". Sono riportate le attività svolte, dai vari enti coinvolti, dal M13 al M18, suddivisi per WP (Work Package).Source: ISTI Project Report, Accordo ASI-INAF n. 2020-6-HH.0, RT2_2019-2021, 2022
Bianchi G., Teofilatto P., Piergentili F., Valentini G., Buzzoni A., Di Lizia P., Colombo C., Rossi A., Pardini C., Francesconi A., Anselmo L.
Questo documento è il terzo deliverable dell'accordo di collaborazione tra ASI e INAF in ambito "Detriti Spaziali- Supporto alle attività IADC e SST 2019-2021". Sono riportate le attività svolte, dai vari enti coinvolti, dal M13 al M18, suddivisi per WP (Work Package).Source: ISTI Project Report, Accordo ASI-INAF n. 2020-6-HH.0, RT2_2019-2021, 2022
See at: CNR ExploRA
2022
Report
Unknown
Accordo di collaborazione tra ASI e INAF N. 2020-6-HH.0, Deliverable Document RA3_2019-2021 - Detriti spaziali supporto alle attività IADC e SST 2019-2021
Bianchi G., Teofilatto P., Piergentili F., Valentini G., Buzzoni A., Di Lizia P., Colombo C., Rossi A., Pardini C., Francesconi A., Anselmo L.
Questo documento è il quarto deliverable dell'accordo di collaborazione tra ASI e INAF in ambito "Detriti Spaziali- Supporto alle attività IADC e SST 2019-2021". Sono riportate le attività svolte, dai vari enti coinvolti, dal M25 al M30, suddivisi per WP (Work Package).Source: ISTI Project Report, Accordo ASI-INAF n. 2020-6-HH.0, RA3_2019-2021, 2022
Bianchi G., Teofilatto P., Piergentili F., Valentini G., Buzzoni A., Di Lizia P., Colombo C., Rossi A., Pardini C., Francesconi A., Anselmo L.
Questo documento è il quarto deliverable dell'accordo di collaborazione tra ASI e INAF in ambito "Detriti Spaziali- Supporto alle attività IADC e SST 2019-2021". Sono riportate le attività svolte, dai vari enti coinvolti, dal M25 al M30, suddivisi per WP (Work Package).Source: ISTI Project Report, Accordo ASI-INAF n. 2020-6-HH.0, RA3_2019-2021, 2022
See at: CNR ExploRA
2022
Contribution to conference
Open Access
The impact of space activities in Low Earth Orbit
Anselmo L., Pardini C.
Debris mitigation measures, gradually adopted since the 1980s, coupled with the end of the Cold War, at the beginning of the 1990s, have played a positive role over a couple of decades. Unfortunately, during the last 15 years, their benefits have been canceled by some major fragmentation events, by prolonged periods of extremely low solar activity and atmospheric drag, and by a dramatic increase in the launch rate of satellites. To aim for the goal of long -term sustainability of space activities, it is necessary to define an acceptable orbital debris environment. Of course, it is not immutable, but relies upon the technical solutions available at a certain time, and on how and for what the circumterrestrial space is used. Assuming the criteria identified more than 20 years ago to define a desirable , tolerable or unacceptable orbital debris environment, an acceptable one, at least in the medium term, should be characterized by a collision rate among objects > 10 cm as stable as possible compared to the current one, and in any case not more than 2or 3 times higher. Taking into account the present technological developments, and the deployment plans of mega-constellations and small satellites, the criticality threshold in LEO might be exceeded during the next ten years. The coming decade is therefore crucial for the future of space activities in LEO, and the widespread application of the debris mitigation measures recommended since the 2000s will probably not be enough. To counteract the negative trends, a combination of reinforced mitigation measures and operational capabilities, complemented by remediation initiatives, as the active removal of selected massive objects abandoned in critical regions of space, should be promoted and implemented.Source: Sustainable Space Flight - An open webinar where Industry meets Academia and the Public, Bergen, Norway, 4/05/2022
Anselmo L., Pardini C.
Debris mitigation measures, gradually adopted since the 1980s, coupled with the end of the Cold War, at the beginning of the 1990s, have played a positive role over a couple of decades. Unfortunately, during the last 15 years, their benefits have been canceled by some major fragmentation events, by prolonged periods of extremely low solar activity and atmospheric drag, and by a dramatic increase in the launch rate of satellites. To aim for the goal of long -term sustainability of space activities, it is necessary to define an acceptable orbital debris environment. Of course, it is not immutable, but relies upon the technical solutions available at a certain time, and on how and for what the circumterrestrial space is used. Assuming the criteria identified more than 20 years ago to define a desirable , tolerable or unacceptable orbital debris environment, an acceptable one, at least in the medium term, should be characterized by a collision rate among objects > 10 cm as stable as possible compared to the current one, and in any case not more than 2or 3 times higher. Taking into account the present technological developments, and the deployment plans of mega-constellations and small satellites, the criticality threshold in LEO might be exceeded during the next ten years. The coming decade is therefore crucial for the future of space activities in LEO, and the widespread application of the debris mitigation measures recommended since the 2000s will probably not be enough. To counteract the negative trends, a combination of reinforced mitigation measures and operational capabilities, complemented by remediation initiatives, as the active removal of selected massive objects abandoned in critical regions of space, should be promoted and implemented.Source: Sustainable Space Flight - An open webinar where Industry meets Academia and the Public, Bergen, Norway, 4/05/2022
See at:
ISTI Repository | www.uib.no | CNR ExploRA
2022
Contribution to conference
Open Access
How the re-entry casualty risk could be impacted by future launch traffic?
Pardini C., Anselmo L.
The launch of mega-constellations in low LEO, together with the disposal of satellites from higher orbits, will entail a significant increase of the kinetic casualty risk in the coming years. The analysis based on the last 12 years, i.e. the time period preceding and partially overlapping such transition phase, confirms that the global casualty probability is still quite low, of the order or less than 2-3% per year. However, if another 4000 or 20,000 satellites were to re-enter without control every year, the probability of having at least one casualty would become about 30% and 80%, respectively, probably reaching unacceptable values for safety on the ground and in airspace. In order to minimize such risk, the components of a satellite should be designed and made of materials able to maximize the probability of being burned upon re-entry into the atmosphere. However, also this strategy might not be the most appropriate over relatively long periods of time and for thousands of re-entering objects, due to the release, in the upper atmosphere, of large quantities of chemical substances having a negative impact on the environment. There is therefore no simple way to address this issue, but it will still be essential that these problems are well analyzed and discussed to avoid running into an irreversible situation, where the re-entry risk is at that point too high to be controlled.Source: Space Debris Risk Assessment and Mitigation Analysis Workshop, Darmstadt, Germany, 23-24/06/2022
Pardini C., Anselmo L.
The launch of mega-constellations in low LEO, together with the disposal of satellites from higher orbits, will entail a significant increase of the kinetic casualty risk in the coming years. The analysis based on the last 12 years, i.e. the time period preceding and partially overlapping such transition phase, confirms that the global casualty probability is still quite low, of the order or less than 2-3% per year. However, if another 4000 or 20,000 satellites were to re-enter without control every year, the probability of having at least one casualty would become about 30% and 80%, respectively, probably reaching unacceptable values for safety on the ground and in airspace. In order to minimize such risk, the components of a satellite should be designed and made of materials able to maximize the probability of being burned upon re-entry into the atmosphere. However, also this strategy might not be the most appropriate over relatively long periods of time and for thousands of re-entering objects, due to the release, in the upper atmosphere, of large quantities of chemical substances having a negative impact on the environment. There is therefore no simple way to address this issue, but it will still be essential that these problems are well analyzed and discussed to avoid running into an irreversible situation, where the re-entry risk is at that point too high to be controlled.Source: Space Debris Risk Assessment and Mitigation Analysis Workshop, Darmstadt, Germany, 23-24/06/2022
See at:
ISTI Repository | CNR ExploRA
2022
Contribution to conference
Unknown
The need to establish a collective risk limit for the re-entry of satellites from mega constellations
Pardini C., Anselmo L.
On the need to establish a collective risk limit for the re-entry of satellites from mega constellations.Source: 40th IADC Annual Meeting, Jeju Island, South Korea, 10-13/10/2022
Pardini C., Anselmo L.
On the need to establish a collective risk limit for the re-entry of satellites from mega constellations.Source: 40th IADC Annual Meeting, Jeju Island, South Korea, 10-13/10/2022
See at: CNR ExploRA
2022
Contribution to conference
Unknown
Italian Space Agency Space Debris Mitigation Activities - Delegation Report
Vellutini E., Anselmo L.
Report to IADC WG-4 of the space debris mitigation activities carried out by ASI since the previous IADC plenary meeting.Source: 40th Inter-Agency Space Debris Coordination Committee (IADC) Plenary (Hybrid) Meeting, Jeju Island, Republic of Korea, 10-13/10/2022
Vellutini E., Anselmo L.
Report to IADC WG-4 of the space debris mitigation activities carried out by ASI since the previous IADC plenary meeting.Source: 40th Inter-Agency Space Debris Coordination Committee (IADC) Plenary (Hybrid) Meeting, Jeju Island, Republic of Korea, 10-13/10/2022
See at: CNR ExploRA
2022
Contribution to conference
Unknown
How to assess and manage the risk from uncontrolled re-entries in view of future developments of space activities
Pardini C., Anselmo L.
We are currently experiencing profound transformations in space activities. The number of operational satellites could increase tenfold over the next decade, radically changing the modalities and scale of space operations. The risk in the airspace and on the ground, due to the uncontrolled re-entry of satellites into the Earth's atmosphere, could increase as well in consequence of the huge number of new payloads placed in low altitude orbits, or disposed from higher orbits in order to comply with space debris mitigation measures. To date the re-entry risk has been assessed and managed on an object-by-object basis, such as assessing whether or not a single event might exceed a certain casualty expectancy threshold, typically set equal to 10-4. However, in view of future developments in space activities, characterized by the launch of numerous small satellites and mega-constellations, it may be necessary to shift to a more holistic approach to the problem, at the very least more system-oriented than object-oriented. As a matter of fact, for instance, even if a single satellite re-entering from a mega-constellation has a casualty expectancy of the order of 10-5, i.e. below the alert threshold of 10-4, 100 of such satellites re-entering annually would have a casualty expectancy of about 10-3, i.e. comparable to that of various past events, e.g. the re-entry of the NASA's spacecraft UARS or the Chinese space station Tiangong-1, which received great international attention. However, so far no collective risk limit has been established for spacecraft re-entries, and even managing that risk according to the US Range Commanders Council (RCC) recommendations, the proposed annual collective risk for the general public has been already marginally exceeded by the re-entry of the Starlink satellites in 2020. A priority action for the next few years will therefore be to at least establish a cumulative risk threshold on an annual basis, so that uncontrolled re-entries can be managed before their associated risk becomes too high to be controlled. The aim of this analysis is first to introduce one or more metrics to characterize and to classify the risk associated to uncontrolled re-entries, occurred during the transition phase between the old and new space activities (2010-2021), then to apply such metrics to possible scenarios, roughly representing space activities in the next few decades. An object-oriented approach is applied to single events in order to identify potentially risky re-entries - based on international regulations - and the re-entry risk evolution over the last 12 years. Successively, a system-oriented strategy is introduced - currently based on the RCC guidelines - to manage the annual collective risk associated with re-entries from mega-constellations. Based on the scenarios simulated, projections of the re-entry risk are carried out over the next 3 decades, also considering the predictions for the world population increase. The possible challenges to be faced in the near future to manage an ever-increasing growth in uncontrolled re-entries conclude this analysis.Source: COSPAR 2022 44th Scientific Assembly, Athens, Greece, 16-24/07/2022
Pardini C., Anselmo L.
We are currently experiencing profound transformations in space activities. The number of operational satellites could increase tenfold over the next decade, radically changing the modalities and scale of space operations. The risk in the airspace and on the ground, due to the uncontrolled re-entry of satellites into the Earth's atmosphere, could increase as well in consequence of the huge number of new payloads placed in low altitude orbits, or disposed from higher orbits in order to comply with space debris mitigation measures. To date the re-entry risk has been assessed and managed on an object-by-object basis, such as assessing whether or not a single event might exceed a certain casualty expectancy threshold, typically set equal to 10-4. However, in view of future developments in space activities, characterized by the launch of numerous small satellites and mega-constellations, it may be necessary to shift to a more holistic approach to the problem, at the very least more system-oriented than object-oriented. As a matter of fact, for instance, even if a single satellite re-entering from a mega-constellation has a casualty expectancy of the order of 10-5, i.e. below the alert threshold of 10-4, 100 of such satellites re-entering annually would have a casualty expectancy of about 10-3, i.e. comparable to that of various past events, e.g. the re-entry of the NASA's spacecraft UARS or the Chinese space station Tiangong-1, which received great international attention. However, so far no collective risk limit has been established for spacecraft re-entries, and even managing that risk according to the US Range Commanders Council (RCC) recommendations, the proposed annual collective risk for the general public has been already marginally exceeded by the re-entry of the Starlink satellites in 2020. A priority action for the next few years will therefore be to at least establish a cumulative risk threshold on an annual basis, so that uncontrolled re-entries can be managed before their associated risk becomes too high to be controlled. The aim of this analysis is first to introduce one or more metrics to characterize and to classify the risk associated to uncontrolled re-entries, occurred during the transition phase between the old and new space activities (2010-2021), then to apply such metrics to possible scenarios, roughly representing space activities in the next few decades. An object-oriented approach is applied to single events in order to identify potentially risky re-entries - based on international regulations - and the re-entry risk evolution over the last 12 years. Successively, a system-oriented strategy is introduced - currently based on the RCC guidelines - to manage the annual collective risk associated with re-entries from mega-constellations. Based on the scenarios simulated, projections of the re-entry risk are carried out over the next 3 decades, also considering the predictions for the world population increase. The possible challenges to be faced in the near future to manage an ever-increasing growth in uncontrolled re-entries conclude this analysis.Source: COSPAR 2022 44th Scientific Assembly, Athens, Greece, 16-24/07/2022
See at: CNR ExploRA