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The Space Safety Programme, formerly the Space Situational Awareness (SSA) programme, is the European Space Agency's (ESA) initiative to monitor hazards from space, determine their risk, make this data available to the appropriate authorities and where possible, mitigate the threat. [1]
The SSA Programme was designed to support Europe's independent space access and utilization through the timely and accurate information delivery regarding the space environment, particularly hazards to both in-orbit and ground infrastructure. [2] In 2019 it evolved into the present Space Safety Programme with an expanded focus, also including missions and activities to mitigate and prevent dangers from space. [3] The programme is split into four main segments: [4]
The Space Safety programme is being implemented as an optional ESA programme with financial participation by 14 Member States. The programme started in 2009 and its mandate was extended until 2019. The second phase of the programme received €46.5 million for the 2013–2016 period. [4]
The main objective of the space weather segment (SWE) is to detect and forecast of space weather events, avoid adverse effect on European space assets and ground-based infrastructure. To achieve that, the segment will focus on delivery of real-time space weather information, forecasts and warnings, supported by a data archive, applications and services. Assets currently available for the segment consist of multiple ground-based and spaceborne sensors monitoring the Sun, solar wind and Earth's magnetosphere, ionosphere and thermosphere. These include the PROBA2 satellite and the Kanzelhoehe Solar Observatory. The segment is jointly coordinated by the SWE Data Centre located at the ESTRACK Redu Station and the SSA Space Weather Coordination Centre (SSCC), both in Belgium. [10]
The near-Earth object segment aims to deliver monitoring and warning of potential Earth impactors and tracking of newly discovered objects. The segment's current assets consist of a mixture of professional and amateur telescopes, including the OGS Telescope, that are supported by tracking databases. The plans are to create a fully integrated system supporting alerts for civil authorities, including the NEOSTEL flyeye telescope due for completion in 2020. The segment is operated by the SSA NEO Coordination Centre located at the ESA Centre for Earth Observation, Italy. [11]
The SST segment's primary goal is the detection, cataloguing and orbit prediction of objects orbiting the Earth. It is part of an effort to avoid collisions between orbiting satellites and debris, provide safe reentries, detect on-orbit explosions, assist missions at launch, deployment and end-of-life and overall reduce cost of space access. The segment currently relies on existing European radar and optical systems. Some of its assets are existing radio and optical telescopes, with now serving a secondary role for tracking space debris. [12]
The radar-based SST assets are split into two categories: surveillance and tracking systems. SSA SST radar systems include: [13]
SSA SST optical surveillance and tracking assets include: [14]
As part of the SSA Programme new, dedicated surveillance radar supported by optical sensors systems will be developed. The segment is coordinated by the Space Surveillance Test & Validation (SSTC) Centre located at the ESAC in Spain. [12]
Close approaches of Near-Earth objects and near earth asteroids are reported by ESA through the space situational awareness center. [16]
Asteroid impact avoidance encompasses the methods by which near-Earth objects (NEO) on a potential collision course with Earth could be diverted away, preventing destructive impact events. An impact by a sufficiently large asteroid or other NEOs would cause, depending on its impact location, massive tsunamis or multiple firestorms, and an impact winter caused by the sunlight-blocking effect of large quantities of pulverized rock dust and other debris placed into the stratosphere. A collision 66 million years ago between the Earth and an object approximately 10 kilometers wide is thought to have produced the Chicxulub crater and triggered the Cretaceous–Paleogene extinction event that is understood by the scientific community to have caused the extinction of all non-avian dinosaurs.
Radar astronomy is a technique of observing nearby astronomical objects by reflecting radio waves or microwaves off target objects and analyzing their reflections. Radar astronomy differs from radio astronomy in that the latter is a passive observation and the former an active one. Radar systems have been conducted for six decades applied to a wide range of Solar System studies. The radar transmission may either be pulsed or continuous. The strength of the radar return signal is proportional to the inverse fourth-power of the distance. Upgraded facilities, increased transceiver power, and improved apparatus have increased observational opportunities.
The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of United States Space Command and operated by the United States Space Force and its functions are:
The Medicina Radio Observatory is an astronomical observatory located 30 km from Bologna, Italy. It is operated by the Institute for Radio Astronomy of the National Institute for Astrophysics (INAF) of the government of Italy.
The Tracking & Imaging Radar (TIRA) system serves as the central experimental facility for the development and investigation of radar techniques for the detection and reconnaissance of objects in space, and of air targets.
Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medicine, and physics all apply to the space research environment. The term includes scientific payloads at any altitude from deep space to low Earth orbit, extended to include sounding rocket research in the upper atmosphere, and high-altitude balloons.
Space domain awareness is the study and monitoring of satellites orbiting the Earth. It involves the detection, tracking, cataloging and identification of artificial objects, i.e. active/inactive satellites, spent rocket bodies, or fragmentation debris.
The Space Surveillance Telescope (SST) is a Southern Hemisphere-based United States Space Force telescope used for detecting, tracking, and cataloguing satellites, near-Earth objects, and space debris.
The Institute for Astronomy, Astrophysics, Space Applications, and Remote Sensing is a non-profit research institute in Greece with expertise in multidisciplinary astrophysical, space and environmental sciences. It is an independent research Institute of the National Observatory of Athens (NOA) established in 2012 from the merging of the Institute of Astronomy and Astrophysics and the Institute of Space Applications and Remote Sensing. The scientists of the Institute have broad knowledge in various areas of observational Astrophysics, Space Science and Earth observation techniques and their applications. They have established collaborations with research groups in Europe and United States, and their work is recognized through publications in refereed journals, invited talks at international conferences, and coordination of EU-funded and ESA-funded research projects. More details on the IAASARS and its activities can be found in its annual report.
Beam park is a radar mode used for space surveillance, particularly tracking space debris. In beam-park mode, a radar beam is kept in a fixed direction with respect to the Earth, while objects passing through the beam are tracked. In 24 hours, as a result of the Earth’s rotation, the radar effectively scans a narrow strip through 360° of the celestial sphere. The scattered waves are detected by a receiver and the measurements obtained during the observations can be used to determine object radar cross-section, time of peak occurrence, polarization ratio, doppler shift and object rotation. The obtained information for each object is then processed and matched against data from previously catalogued objects. The beam-park mode can be used to detect both previously known and uncatalogued objects at any altitude, provided that the reflected power captured by the receiver can be distinguished from the noise. This limits the use of radar-based beam park observations to objects in Low-Earth Orbit (LEO). Optical instruments, in turn, have very good performance for objects in Geostationary Earth Orbit (GEO) and in Geostationary Transfer Orbit (GTO). The radar technique typically outperforms optical facilities in LEO and can conduct observations for longer periods, both during day and night, independently of the weather and object illumination by sunlight.
The Double Asteroid Redirection Test (DART) was a NASA space mission aimed at testing a method of planetary defense against near-Earth objects (NEOs). It was designed to assess how much a spacecraft impact deflects an asteroid through its transfer of momentum when hitting the asteroid head-on. The selected target asteroid, Dimorphos, is a minor-planet moon of the asteroid Didymos; neither asteroid poses an impact threat to Earth, but their joint characteristics made them an ideal benchmarking target. Launched on 24 November 2021, the DART spacecraft successfully collided with Dimorphos on 26 September 2022 at 23:14 UTC about 11 million kilometers from Earth. The collision shortened Dimorphos' orbit by 32 minutes, greatly in excess of the pre-defined success threshold of 73 seconds. DART's success in deflecting Dimorphos was due to the momentum transfer associated with the recoil of the ejected debris, which was substantially larger than that caused by the impact itself.
Vigil, formerly known as Lagrange, is a space weather mission developed by the European Space Agency. The mission will provide the ESA Space Weather Office with instruments able to monitor the Sun, its solar corona and interplanetary medium between the Sun and Earth, to provide early warnings of increased solar activity, to identify and mitigate potential threats to society and ground, airborne and space based infrastructure as well as to allow 4 to 5 days space weather forecasts. To this purpose the Vigil mission will place for the first time a spacecraft at Sun-Earth Lagrange point 5 (L5) from where it would get a 'side' view of the Sun, observing regions of solar activity on the solar surface before they turn and face Earth.
As the space race came to an end, a new rationale for investment in space exploration emerged, focused on the pragmatic use of space for improving life on Earth. The legacy of the space race is that nations continue to pursue space exploration to enhance their prestige. As the justification for government-funded space programs shifted to "the public good", space agencies began to articulate and measure the wider socio-economic benefits that might derive from their activities, including both the direct and indirect benefits of space exploration. However, such programs have also been criticized with several drawbacks cited.
Asteroid impact prediction is the prediction of the dates and times of asteroids impacting Earth, along with the locations and severities of the impacts.
The Near Earth Object Survey TELescope is an astronomical survey and early-warning system for detecting near-Earth objects sized 40 metres and above a few weeks before they impact Earth.
Dimorphos is a natural satellite or moon of the near-Earth asteroid 65803 Didymos, with which it forms a binary system. The moon was discovered on 20 November 2003 by Petr Pravec in collaboration with other astronomers worldwide. Dimorphos has a diameter of 177 meters (581 ft) across its longest extent and it was the target of the Double Asteroid Redirection Test (DART), a NASA space mission that deliberately collided a spacecraft with the moon on 26 September 2022 to alter its orbit around Didymos. Before the impact by DART, Dimorphos had a shape of an oblate spheroid with a surface covered in boulders but virtually no craters. The moon is thought to have formed when Didymos shed its mass due to its rapid rotation, which formed an orbiting ring of debris that conglomerated into a low-density rubble pile that became Dimorphos today.
Space sustainability aims to maintain the safety and health of the space environment, as well as planetary environments.
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