Michael Kueppers

European Space Agency | ESA · Science Operations Department

NASA’s Double Asteroid Redirection Test (DART) and ESA’s Hera missions offer a unique opportunity to investigate the delivery of impact ejecta to other celestial bodies. We performed ejecta dynamical simulations using 3 million particles categorized into three size populations (10 cm, 0.5 cm, and 30 μ m) and constrained by early postimpact LICIACub...

NASA's DART and ESA's Hera missions offer a unique opportunity to investigate the delivery of impact ejecta to other celestial bodies. We performed ejecta dynamical simulations using 3 million particles categorized into three size populations (10 cm, 0.5 cm, and 30 $\mu$m) and constrained by early post-impact LICIACube observations. The main simula...

NASAʼs Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the missionʼs Level 1 requirements guided its planetary defense investigations. Here, we summarize DARTʼs achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos ne...

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are...

The impact of the Double Asteroid Redirection Test spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos’s orbit substantially, largely from the ejection of material. We present results from 12 Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days af...

Hera is a European Space Agency (ESA) space mission, part of the Asteroid Impact and Deflection Assessment (AIDA) international collaboration with NASA, with a targeted launch to the Didymos system next October 2024. Following last 26 September 2022 extremely successful NASA’s DART impact on Dimorphos, the secondary body of the Didymos binary syste...

Between 2014 December 31 and 2015 March 17, the OSIRIS cameras on Rosetta documented the growth of a 140m wide and 0.5m deep depression in the Hapi region on Comet 67P/Churyumov-Gerasimenko. This shallow pit is one of several that later formed elsewhere on the comet, all in smooth terrain that primarily is the result of airfall of coma particles. W...

Between 2014 December 31 and 2015 March 17, the OSIRIS cameras on Rosetta documented the growth of a 140 m wide and 0.5 m deep depression in the Hapi region on Comet 67P/Churyumov–Gerasimenko. This shallow pit is one of several that later formed elsewhere on the comet, all in smooth terrain that primarily is the result of airfall of coma particles....

We review the history of spacecraft encounters with comets, concentrating on those that took place in the recent past, since the publication of the Comets II book. This includes the flyby missions Stardust and Deep Impact, and their respective extended missions, the Rosetta rendezvous mission, and serendipitous encounters. While results from all of...

The Hera mission is under development in the ESA Space Safety Programme for launch in October 2024. Hera will contribute to the first deflection test of an asteroid with the NASA DART mission, in the framework of the international NASA- and ESA supported Asteroid Impact and Deflection Assessment (AIDA) collaboration. Once NASA DART will have perfor...

29P/Schwassmann-Wachmann 1 is a distant Centaur/comet, showing persistent CO-driven activity and frequent outbursts. We used the Herschel space observatory in 2010, 2011, and 2013 to observe H$_2$O and NH$_3$ and to image the dust coma. Observations with the IRAM 30 m were undertaken in 2007, 2010, 2011, and 2021 to monitor the CO production rate a...

The Hera mission is in Phase C for launch in 2024 in the ESA Space Safety Programme. Each space mission to an asteroid, whether its requirements are driven by planetary defense, science or other objectives, has a science return that is always extremely high. The reason is that our knowledge of these fascinating objects still needs major improvement...

The Double Asteroid Redirection Test (DART) is a Planetary Defense mission, designed to demonstrate the kinetic impactor technique on (65803) Didymos I Dimorphos, the secondary of the (65803) Didymos system. DART has four level 1 requirements to meet in order to declare mission success: (1) impact Dimorphos between 2022 September 25 and October 2,...

The Hera mission is in development for launch in 2024 within the ESA Space Safety Program. Hera will contribute to the first deflection test of an asteroid, in the framework of the international NASA and ESA-supported Asteroid Impact and Deflection Assessment (AIDA) collaboration. Hera will also offer a great science return.

The data from the Rosetta mission have permitted a reconstruction of the shape of comet 67P/Churyumov-Gerasimenko and an identification of the terrains and features forming the surface. The peculiar shape of the comet has made it challenging to project these geological features onto an unambiguous frame. As a result, the geological maps published t...

Hera is a mission under development in the ESA Space Safety Program, whose primary objective is to perform detailed measurements of the outcome of the NASA DART kinetic impactor test on the moon Dimorphos of the binary asteroid 65803 Didymos. Hera is equipped with 5 instruments on the main spacecraft plus two cubesats with two instruments each. Thi...

The Hera mission is under development in the ESA Space Safety Program for launch in 2024. Hera will contribute to the first deflection test of an asteroid, in the framework of the international NASA- and ESA-supported Asteroid Impact and Deflection Assessment (AIDA) collaboration. ESA's Hera spacecraft will rendezvous the binary asteroid 65803 Didy...

Rosetta was a European Space Agency (ESA) cornerstone mission that launched in March 2004, exited hibernation in January 2014, entered orbit around the comet 67P/Churyumov-Gerasimenko in August 2014, and escorted the comet through September 2016, executing the most detailed study of a comet ever undertaken by humankind. The Rosetta Orbiter had 11 s...

On 12 November 2014, the Philae lander descended towards comet 67P/Churyumov–Gerasimenko, bounced twice off the surface, then arrived under an overhanging cliff in the Abydos region. The landing process provided insights into the properties of a cometary nucleus1–3. Here we report an investigation of the previously undiscovered site of the second t...

The Hera mission has been approved for development and launch in the new ESA Space SafetyProgramme by the ESA Council at Ministerial Level, Space19+, in November 2019. Hera will contributeto the first deflection test of an asteroid, in the framework of the international NASA- and ESA supportedAsteroid Impact and Deflection Assessment (AIDA) collabo...

Asteroids (24) Themis and (65) Cybele have an absorption feature at 3.1 μm reported to be directly linked to surface water ice. We searched for water vapor escaping from these asteroids with the Herschel Space Observatory Heterodyne Instrument for the Far Infrared. While no H2O line emission was detected, we obtain sensitive 3σ water production rat...

Aims. We provide a measurement of the seasonal evolution of the dust deposit erosion and accretion in the Hapi region of comet 67P/Churyumov-Gerasimenko with a vertical accuracy of 0.2–0.9 m. Methods. We used OSIRIS Narrow Angle Camera images with a spatial scale of lower than 1.30 m px−1 and developed a tool to monitor the time evolution of 22 bou...

The AIDA (Asteroid Impact & Deflection Assessment) is a collaboration between NASA DART mission and ESA Hera mission. The aim is to study asteroid deflection through a kinetic collision. For this mission two spacecrafts will be developed DART provided by NASA and HERA provided by ESA. DART spacecraft will collide with Didymoon, while the orbit chan...

The surface of the dwarf planet Ceres is considered to be dominated by geological processes typical of small bodies or medium-sized icy bodies, such as impact cratering1,2; there are also features of putative cryovolcanic origin³ as well as those related to flow of near-surface ice⁴. Extensional features4–6 include regional linear troughs, fracture...

The large domes found on the dwarf planet Ceres may not result from cryovolcanism, but from solid-state flow analogous to salt doming on Earth, according to numerical simulations of gravitational loading.

This study deals with an aspect of blocks observed on many rocky planetary surfaces: in situ fragmentation. Using LROC/NAC images, we characterized the morphology, morphometry and abundance of in-situ fractured blocks observed on the rim of six large impact craters of known emplacement age on the Moon. The relative number of disrupted blocks increa...

Context. The cold gas system and anchoring harpoons that were designed to hold Philae down after it landed on the Agilkia region of comet 67P/Churyumov-Gerasimenko (67P) failed. This caused the lander to move on a complex trajectory that comprised multiple impacts and rebounds. The motion of Philae was mainly dominated by the gravitational environm...

LIDAR and rangefinders are among the most important instruments for an asteroid mission, a consequently a critical technology for planetary defense. They support spacecraft navigation, from fly by to landing operations and can also provide scientific data, such as relative velocity, falling velocity and reflectance measurements at laser wavelength....

In keeping with the Luxembourg government's initiative to support the future use of space resources, ASIME 2018 was held in Belval, Luxembourg on April 16-17, 2018. The goal of ASIME 2018: Asteroid Intersections with Mine Engineering, was to focus on asteroid composition for advancing the asteroid in-space resource utilisation domain. What do we kn...

HERA is an ESA mission that, if selected, will be launched towards the Didymos binary asteroid system in 2023 while the NASA’s Double Asteroid Redirection Test (DART) spacecraft will impact on Didymos’ moon, Didy- moon, in 2022. HERA will perform a detailed post DART-impact survey. It aims to characterize physical and dynamical properties of Didymo...

Hera is an ESA mission of opportunity whose primary objective is to observe and validate the outcome of a kinetic impactor deflection test on a Near-Earth Asteroid, thus providing valuable information for future mitigation capabilities. Hera is part of the international Asteroid Impact & Deflection Assessment (AIDA) mission, together with NASA’s Do...

In recent years, the dwarf planet Ceres has been found to release water vapor. Detailed investigation of the surface and subsurface by NASA's Dawn mission reveal localized patches of surface ice and an ice abundance of around 10% in the shallow subsurface, within a meter below the surface. Landis et al. (2019, https://doi.org/10.1029/2018JE005780)...

Accepted for publication on Astronomy and Astrophysics on 27 August 2018. 27 pages, 18 figures, 2 tables

Aims. We investigate the surface distribution of the source regions of dust jets on comet 67P/Churyumov-Gerasimenko as a function of time. Methods. The dust jet source regions were traced by the comprehensive imaging data set provided by the OSIRIS scientific camera. Results. We show in detail how the projected footpoints of the dust jets and hence...

HERA is a candidate ESA mission that will be launched to Didymos binary asteroid system in 2023. It will perform a detailed post-impact survey of the smaller of the two bodies, Didymoon, following the kinetic impact by the NASA’s Double Asteroid Redirection Test (DART) planned in 2022. DART and Hera were conceived together as part of the internatio...

On the 12th of November 2014, the Rosetta Philae Lander descended to make the first soft touchdown on the surface of a comet – comet 67P/Churyumov-Gerasimenko. That soft touchdown did occur but due to the failure in the firing of its two harpoons, Philae bounced and travelled across the comet making contact with the surface twice more before fina...

TIRI is a multi-purpose Thermal InfraRed (TIR) Imager, initially designed for the Asteroid Impact Mission, an ESA Technology Mission of Opportunity targeting Didymos, a binary near–Earth asteroid. TIRI is conceived to pursue scientific and technology development goals. It will be used to determine asteroid surface physical parameters, such as tempe...

Between 2014 and 2016, ESA's Rosetta OSIRIS cameras acquired multiple-filters images of the layered nucleus of comet 67P/Churyumov-Gerasimenko, ranging from ultraviolet to near-infrared wavelengths. No correlation between layers disposition and surface spectral variegation has been observed so far. This paper investigates possible spectral differen...

The Rosetta space probe accompanied comet 67P/Churyumov-Gerasimenko for more than two years, obtaining an unprecedented amount of unique data of the comet nucleus and inner coma. This work focuses identifying the source regions of faint jets and outbursts and on studying the spectrophotometric properties of some outbursts. We use observations acqui...

In the frame of Near-Earth-Object exploration and planetary defence, the two-part AIDA mission is currently studied by NASA and ESA. Being composed of a kinetic impactor, DART (NASA), and by an observing spacecraft, AIM (ESA), AIDA has been designed to deliver vital data to determine the momentum transfer efficiency of a kinetic impact onto a small...

While the structural complexity of cometary comae is already recognizable from telescopic observations1, the innermost region, within a few radii of the nucleus, was not resolved until spacecraft exploration became a reality2,3. The dust coma displays jet-like features of enhanced brightness superposed on a diffuse background1,4,5. Some features ca...

The international Rosetta mission was launched on 2nd March 2004 for a ten year journey to its target destination, comet 67P/Churyumov-Gerasimenko. Following the January 2014 exit from a 31 month hibernation period, Rosetta approached and rendezvoused with the comet in August 2014. On 12th November 2014, the Philae lander was deployed from Rosetta...

The OSIRIS camera onboard Rosetta measured the phase function of both the coma dust and the nucleus. The two functions have a very different slope versus the phase angle. Here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. This makes the dust bursts observe...

The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the d...

The Asteroid Impact & Deflection Assessment (AIDA) mission is an international cooperation between NASA and ESA. NASA plans to provide the Double Asteroid Redirection Test (DART) mission which will perform a kinetic impactor experiment to demonstrate asteroid impact hazard mitigation. ESA proposes to provide the Hera mission which will rendezvous w...

We directly measure twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimate the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around one Pa or less (one to five Pa, when scaled to a metre length)....

The European component of the joint ESA-NASA Asteroid Impact & Deflection Assessment (AIDA) mission has been redesigned from the original version called Asteroid Impact Mission (AIM), and is now called Hera. The main objectives of AIDA are twofold: (1) to perform an asteroid deflection test by means of a kinetic impactor under detailed study at NAS...

Context. The camera OSIRIS on board Rosetta obtained high-resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko (67P). Great parts of the nucleus surface are composed of fractured terrain. Aims. Fracture formation, evolution, and their potential relationship to physical processes that drive activity are not yet fully understood. Obser...

Our knowledge of the internal structure of asteroids is, so far, indirect – relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling of formation and evolution. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape asteroid internal structures?...

On 3 July 2016, several instruments on board ESA's Rosetta spacecraft detected signs of an outburst event on comet 67P, at a heliocentric distance of 3.32 AU from the sun, outbound from perihelion. We here report on the inferred properties of the ejected dust and the surface change at the site of the outburst. The activity coincided with the local...

Our knowledge of the internal structure of asteroids is, so far, indirect – relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling of formation and evolution. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape asteroid internal structures?...

In the frame of NEO exploration and planetary defence, the two-part AIDA mission is currently studied by NASA and ESA. Being composed of a kinetic impactor, DART (NASA), and by an observing spacecraft, AIM (ESA), AIDA has been designed to deliver vital data to determine the momentum transfer efficiency of a kinetic impact onto a small body and the...

In the course of the AIDA/AIM mission studies [1,2] a lander, MASCOT2, has been studied to be deployed on the moon of the binary Near-Earth Asteroid system, (65803) Didymos. The AIDA technology demonstration mission, composed of a kinetic impactor, DART, and an observing spacecraft, AIM, has been designed to deliver vital data to determine the mome...

Numerous water-ice-rich deposits surviving more than several months on comet 67P/Churyumov-Gerasimenko were observed during the Rosetta mission. We announce the first-time detection of water-ice features surviving up to 2 yr since their first observation via OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) NAC (narrow angle camer...

High-resolution OSIRIS/Rosetta images of 67P/Churyumov-Gerasimenko acquired on the night run of 2016 April 9-10 show, at large scale, an opposition effect (OE) spot sweeping across Imhotep as the phase angle ranges from 0° to 17°. In this work, we fitted the phase curve of the whole surface imaged as well as three particular features using both the...

We report on the detection and characterization of more than 6300 polygons on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, using images acquired by the OSIRIS camera onboard Rosetta between August 2014 and March 2015. They are found in consolidated terrains and grouped in localized networks. They are present at all latitudes (from...

During the rendezvous of the Rosetta spacecraft with comet 67P/Churyumov-Gerasimenko, the OSIRIS scientific cameras monitored the near-nucleus gas environment in various narrow-band filters, observing various fragment species. It turned out that the excitation processes in the innermost coma are significantly different from the overall coma, as obs...

In a Rosetta/OSIRIS imaging activity in 2015 June, we have observed the dynamic motion of particles close to the spacecraft. Due to the focal setting of the OSIRIS wide angle camera, these particles were blurred, which can be used to measure their distances to the spacecraft. We detected 109 dust aggregates over a 130 min long sequence, and find th...

The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dust...

Context. Dust deposits or dust cover are a prevalent morphology in the northern hemi-nucleus of comet 67P/Churyumov-Gerasimenko (67P). The evolution of the dust deposits was captured by the OSIRIS camera system onboard the Rosetta spacecraft having escorted the comet for over two years. The observations shed light on the fundamental role of cometar...

The study of dust, the most abundant material in cometary nuclei, is pivotal in understanding the original materials forming the Solar system. Measuring the coma phase function provides a tool to investigate the nature of cometary dust. Rosetta/OSIRIS sampled the coma phase function of comet 67P/Churyumov-Gerasimenko, covering a large phase angle r...

We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material t...