Mission type | Dual asteroid probes |
---|---|
Operator | ESA / NASA |
Website | AIDA study |
Start of mission | |
Launch date | |
Rocket | |
Dimorphos [5] impactor | |
Spacecraft component | DART |
Impact date | 26 September 2022 |
(65803) Didymos [6] orbiter | |
Spacecraft component | Hera,Milani,Juventas |
Orbital insertion | 14 December 2026 [7] |
The Asteroid Impact and Deflection Assessment (AIDA) missions are a proposed pair of space probes which will study and demonstrate the kinetic effects of crashing an impactor spacecraft into an asteroid moon. The mission is intended to test and validate impact models of whether a spacecraft could successfully deflect an asteroid on a collision course with Earth. [8]
The original plan called for a European spacecraft,the Asteroid Impact Mission (AIM),to operate in synergy with a large NASA impactor called Double Asteroid Redirection Test (DART) and observe the immediate effects of the impact. AIM was cancelled in 2016 when Germany was unable to fund its portion,and after some backlash within European Space Agency (ESA),AIM was replaced in 2018 with a smaller spacecraft called Hera that launched three years after DART to orbit and study the crater on the asteroid. Hera will also deploy two European CubeSats in deep space for close-up asteroid surveying:Juventas and Milani. [9]
DART impacted Dimorphos,the asteroid moonlet of 65803 Didymos,on 26 September 2022. [10] Hera will arrive at Didymos in December 2026,four years and three months after DART's impact. [11]
Initially,Hera's role was to be realized by a much larger spacecraft called Asteroid Impact Mission (AIM), [12] that would have observed the plume,the crater,and the freshly exposed material to provide unique information for asteroid deflection,science and mining communities. In December 2016,the European Space Agency (ESA) cancelled the development of the AIM spacecraft after Germany decided to fund the ExoMars project only. [13] Germany offered to cover only 35 million of the 60 million needed for the AIM portion to continue, [13] and this was not enough to continue development. [14] Had AIM been developed,its notional requirements in 2012 were: [15] [16]
Under the original proposal,AIM would have launched in October 2020,and DART in July 2021. AIM would have orbited the larger asteroid and studied the composition of it and its moon. DART would then impact the asteroid's moon in October 2022,during a close approach to Earth. [19] AIM would have studied the asteroid's strength,surface physical properties and internal structure,as well as measured the effect on the asteroid moon's orbit around the larger asteroid.
Nevertheless,NASA has continued development of the DART mission to 65803 Didymos and plans to measure the effects of the impact from ground-based telescopes, [20] [21] and from an Italian CubeSat DART will bring along. Following AIM's cancellation,ESA director Jan Wörner stated his intentions to revive the European mission in some form. [20] Etienne Schneider,Luxembourg's deputy prime minister,expressed regret at AIM's cancellation,and commented that his country would continue to advocate for the realization of the mission. [22]
By March 2018,Hera proposal was in Phase B1,where the preliminary design was being drawn up. On 7 January 2019,the Hera team announced the selection of two CubeSats to piggyback on the mission:APEX and Juventas. [23] ESA officials approved Hera in November 2019 for a 2024 launch. [24] In September 2020 ESA awarded a contract covering the detailed design,manufacturing,and testing of Hera. [9] In this occasion the APEX CubeSat is also substituted by the Milani one,named after the late Andrea Milani, [25] [26] distinguished professor and leading asteroid scientist.
The Italian Space Agency (ASI) decided in 2018 to contribute to NASA a secondary spacecraft called LICIACube (Light Italian CubeSat for Imaging of Asteroids),a 6-unit CubeSat that piggybacked with DART and separated 15 days before impact on 11 September 2022 to acquire images of the ejecta as it drifts past the asteroid. [27] [28] [29] [30] LICIACube is equipped with two optical science cameras,dubbed LUKE and LEIA.
The AIDA mission is a joint international collaboration of the European Space Agency (ESA),the German Aerospace Center (DLR),Côte d'Azur Observatory (OCA),NASA,and Johns Hopkins University Applied Physics Laboratory (JHU/APL). [19]
The miniature lidar instrument on board Hera will be provided by a consortium of teams from Portugal,Poland,and Ireland. [6] Two CubeSats will be deployed by Hera while at Didymos: [31] The Milani CubeSat is being developed by Italy,Czech Republic,and Finland. [32] [33] The Juventas CubeSat is being developed by GomSpace and GMV's Romanian division. [34]
Along with surveying DART's impact crater,Hera may also carry a Japanese impactor that would be a replica of the Small Carry-on Impactor (SCI),on board the Hayabusa2 asteroid sample return mission. [12] NASA's DART brought a 6U flyby CubeSat along with it,called LICIACube,which was developed by the Italian Space Agency (ASI) to image the ejecta plume. [27] [28] [29]
DART or Double Asteroid Redirection Test was a 500 kg (1,100 lb) impactor that hosted a single camera, Didymos Reconnaissance and Asteroid Camera for Optical Navigation (DRACO), derived from LORRI camera aboard New Horizons, to support autonomous guiding to impact the center of the moon of Didymos B. [35] It also carried an Italian-built cubesat called LICIACube that was released pre-impact on 11 September 2022 to image the event. [36] It is estimated that the impact of the 500 kg (1,100 lb) [37] DART at 6 km/s (3.7 mi/s) [21] will produce a velocity change on the order of 0.4 mm/s, which leads to a small change in the orbit of Didymos B, but over time, a large change in the orbital position (or orbital phase). [15] [19] [16] DART impacted Dimorphos on 26 September 2022. [10]
Hera is the European component of the ESA–NASA AIDA mission. The Hera spacecraft, approved on 29 November 2019, [24] will focus on key measurements to validate impact and asteroid deflection models, such as the detailed characterisation of the impact crater made by the DART impactor. [38] Hera will also measure the DART impact outcome, such as change in the binary system orbit, [38] and will enable detailed characterisation of the Dimorphos volume and surface properties, as well as measure the volume and morphology of the DART impact crater. [39]
The baseline payload of Hera includes a camera, a miniaturized lidar and two CubeSats dedicated to asteroid characterisation. The spacecraft design allows for 40 kilograms (88 lb) of additional payload mass, including the Small Carry-on Impactor (SCI) proposed by Japan's space agency JAXA. Other options, such as a small lander, are being considered. [38] Hera was launched on a Falcon 9 on 7 October 2024. [4]
The notional payloads on Hera are: [16] [12] [6]
This section needs to be updated.(March 2024) |
AIDA will target 65803 Didymos, a binary asteroid system in which one asteroid is orbited by a smaller one. The primary asteroid is about 800 metres (2,600 ft) in diameter; its small satellite is about 150 metres (490 ft) in diameter in an orbit about 1.1 km (0.68 mi) from the primary. Didymos is not an Earth-crossing asteroid, and there is no possibility that the deflection experiment could create an impact hazard to Earth. [16]
The impact of the 300 kilograms (660 lb)DART spacecraft at 6.25 km/s will produce a velocity change on the order of 0.4 mm/s, which leads to a significant change in the mutual orbit of these two objects, but only a minimal change in the heliocentric orbit of the system. [15] [19] [16] AIDA will provide a great benefit obtaining the size of the resulting impact crater in addition to the momentum transfer measurement, as the effects of porosity and strength of the target are needed to calculate the momentum transfer efficiency. [19] [16]
DART impacted the small moon of the asteroid Didymos on 26 September 2022, while Hera would arrive at Didymos in 2027, five years after DART's impact. To maximize scientific outcome, the AIDA team had proposed to delay DART's launch so that Hera would arrive at the asteroid first, enabling it to study DART's impact, the plume, the crater, and the freshly exposed material. [12] While most of the initial objectives of AIDA would still be met if Hera arrives after DART, as a drawback, data from direct observation of the impact and ejecta will not be obtained. [12]
Host spacecraft | Secondary spacecraft | Remarks |
---|---|---|
DART | LICIACube [27] |
|
Hera | Juventas [42] [7] | |
Milani [9] |
|
An asteroid is a minor planet—an object that is neither a true planet nor an identified comet— that orbits within the inner Solar System. They are rocky, metallic, or icy bodies with no atmosphere, classified as C-type (carbonaceous), M-type (metallic), or S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across and larger than meteoroids, to Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies.
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.
A lander is a spacecraft that descends towards, then comes to rest on the surface of an astronomical body other than Earth. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional.
Don Quijote is a past space mission concept that has been studied from 2005 until 2007 by the European Space Agency, and which would investigate the effects of crashing a spacecraft into an asteroid to test whether a spacecraft could successfully deflect an asteroid on a collision course with Earth. The orbiter was designed to last for seven years. The mission did not proceed beyond initial studies.
Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics. That is, they show a coma, tail, or other visual evidence of mass-loss, but their orbits remain within Jupiter's orbit. These bodies were originally designated main-belt comets (MBCs) in 2006 by astronomers David Jewitt and Henry Hsieh, but this name implies they are necessarily icy in composition like a comet and that they only exist within the main-belt, whereas the growing population of active asteroids shows that this is not always the case.
65803 Didymos is a sub-kilometer asteroid and binary system that is classified as a potentially hazardous asteroid and near-Earth object of the Apollo group. The asteroid was discovered in 1996 by the Spacewatch survey at Kitt Peak, and its small 160-meter minor-planet moon, named Dimorphos, was discovered in 2003. Due to its binary nature, the asteroid was then named Didymos, the Greek word for 'twin'.
Strictly speaking, a satellite collision is when two satellites collide while in orbit around a third, much larger body, such as a planet or moon. This definition is typically loosely extended to include collisions between sub-orbital or escape-velocity objects with an object in orbit. Prime examples are the anti-satellite weapon tests. There have been no observed collisions between natural satellites, but impact craters may show evidence of such events. Both intentional and unintentional collisions have occurred between man-made satellites around Earth since the 1980s. Anti-satellite weapon tests and failed rendezvous or docking operations can result in orbital space debris, which in turn may collide with other satellites.
A Mars flyby is a movement of spacecraft passing in the vicinity of the planet Mars, but not entering orbit or landing on it. Uncrewed space probes have used this method to collect data on Mars, as opposed to orbiting or landing. A spacecraft designed for a flyby is also known as a "flyby bus" or "flyby spacecraft".
Patrick Michel is a French planetary scientist, Senior Researcher at CNRS, member of the team TOP of the CNRS and Université Côte d'Azur Lagrange Laboratory at the Côte d'Azur Observatory in Nice (France), and also a Global Fellow of the University of Tokyo.
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.
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.
The Planetary Missions Program Office is a division of NASA headquartered at the Marshall Space Flight Center, formed by the agency's Science Mission Directorate (SMD). Succeeding the Discovery and New Frontiers Program Office, it was established in 2014 to manage the Discovery and New Frontiers programs of low and medium-cost missions by third-party institutions, and the Solar System Exploration program of NASA-led missions that focus on prioritized planetary science objectives. The Discovery and New Frontiers programs were established in 1992 and 2001 respectively, and have launched fourteen primary missions together, along with two missions launched under the administration of the Planetary Missions Program Office. The Solar System Exploration Program was established alongside the office, with three missions planned for launch under the new program.
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.
Light Italian CubeSat for Imaging of Asteroids is a six-unit CubeSat of the Italian Space Agency (ASI). LICIACube is a part of the Double Asteroid Redirection Test (DART) mission and carries out observational analysis of the Didymos asteroid binary system after DART's impact on Dimorphos. It communicates directly with Earth, sending back images of the ejecta and plume of DART's impact as well as having done asteroidal study during its flyby of the Didymos system from a distance of 56.7 km (35.2 mi), 165 seconds after DART's impact. LICIACube is the first purely Italian autonomous spacecraft in deep space. Data archiving and processing is managed by the Mission Control Center of Argotec. Mission ended sometime in the autumn of 2022
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Stephan Ulamec is an Austrian geophysicist, born in Salzburg on January 27, 1966, with more than 100 articles in peer-reviewed journals and several participations in space missions and payloads operated by diverse space agencies. He is working at the German Aerospace Center in Cologne. He is regularly giving lectures about his publications in aerospace engineering at the University of Applied Sciences: Fachhochschule FH-Aachen. Main aspects of his work are related to the exploration of small bodies in the solar system.
Hera is a spacecraft developed by the European Space Agency for its space safety program. Its primary mission objective is to study the Didymos binary asteroid system that was impacted four years earlier by the NASA Double Asteroid Redirection Test (DART) spacecraft and contribute to validation of the kinetic impact method to deviate a near-Earth asteroid from a colliding trajectory with Earth. It will measure the size and morphology of the crater created as well as the momentum transferred by an artificial projectile impacting an asteroid, which will allow measuring the efficiency of the deflection produced by the impact. It will also analyze the expanding debris cloud caused by the impact.