Angela Stickle

• Ph.D
• Senior Research Staff at Johns Hopkins University

The Europa Imaging System (EIS) consists of a Narrow-Angle Camera (NAC) and a Wide-Angle Camera (WAC) that are designed to work together to address high-priority science objectives regarding Europa’s geology, composition, and the nature of its ice shell. EIS accommodates variable geometry and illumination during rapid, low-altitude flybys with both...

One of the youngest features on the Moon is Tycho, an 85 km diameter impact crater with a vast ray system that spans much of the lunar nearside. As such, it serves as an important stratigraphic marker for the Moon. One of Tycho’s longest rays crosses the South Pole, where it intersects several candidate landing sites for NASA’s Artemis III mission,...

The Double Asteroid Redirection Test (DART) had an impact with Dimorphos (a satellite of the asteroid Didymos) on 26 September 2022¹. Ground-based observations showed that the Didymos system brightened by a factor of 8.3 after the impact because of ejecta, returning to the pre-impact brightness 23.7 days afterwards². Hubble Space Telescope observat...

Condensed volatiles within lunar permanently shadowed regions are of high scientific and resource utilization importance. Volatiles remain elusive and difficult to observe directly, due to low direct solar illumination. In this work, we investigate correlations between, as well as possible effects of, condensed volatiles and surface roughness. We a...

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...

The Double Asteroid Redirection Test (DART) mission impacted Dimorphos, the moonlet of the binary asteroid 65803 Didymos, on 2022 September 26 and successfully tested a kinetic impactor as an asteroid deflection technique. The success of the deflection was partly due to the momentum of the excavated ejecta material, which provided an extra push to...

Kinetic deflection is a planetary defense technique that delivers spacecraft momentum to a small body to deviate its course from Earth. The deflection efficiency depends strongly on the impactor and target. Among them, the contribution of global curvature was poorly understood. The ejecta plume created by NASA's DART impact on its target asteroid,...

The Aristarchus plateau represents one of the most complex volcanic provinces on the lunar surface and is host to the largest pyroclastic deposit on the Moon. Lunar pyroclastic deposits offer a window into the Moon’s interior and represent a valuable resource to support a sustained human presence. We present a new analysis of the Aristarchus pyrocl...

Images collected by the DART and LICIAcube spacecraft provide the first resolved views of the Didymos binary asteroid system. These images reveal that the primary asteroid, Didymos, is flattened and has a non-circular equatorial perimeter. At high elevations, its surface is undulating and contains large boulders and craters; at low elevations its s...

Nighttime Lyman Alpha Mapping Project (LAMP) observations are used to investigate condensed volatiles at the south polar region of the Moon. This study incorporates LAMP data from the first ∼7 years of the mission and Diviner annual maximum temperatures to search for volatile signatures associated with H2O, NH3, and CO2. Other stable potential spec...

The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on September 26, 2022 as a planetary defense test. DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defense,...

While no known asteroid poses a threat to Earth for at least the next century, the catalog of near-Earth asteroids is incomplete for objects whose impacts would produce regional devastation. Several approaches have been proposed to potentially prevent an asteroid impact with Earth by deflecting or disrupting an asteroid. A test of kinetic impact te...

Some active asteroids have been proposed to be the result of impact events. Because active asteroids are generally discovered serendipitously only after their tail formation, the process of the impact ejecta evolving into a tail has never been directly observed. NASA's Double Asteroid Redirection Test (DART) mission, apart from having successfully...

The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on September 26, 2022 as a planetary defense test1. DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defense,...

While no known asteroid poses a threat to Earth for at least the next century, the catalog of near-Earth asteroids is incomplete for objects whose impacts would produce regional devastation1,2. Several approaches have been proposed to potentially prevent an asteroid impact with Earth by deflecting or disrupting an asteroid1-3. A test of kinetic imp...

Some active asteroids have been proposed to be the result of impact events1. Because active asteroids are generally discovered serendipitously only after their tail formation, the process of the impact ejecta evolving into a tail has never been directly observed. NASA's Double Asteroid Redirection Test (DART) mission2, apart from having successfull...

The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on September 26, 2022 as a planetary defense test ¹ . DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defens...

The Double Asteroid Redirection Test (DART) Mission, NASA’s first planetary defense mission, will be the first fullscale test of a kinetic impactor. In this test, DART will impact into Dimorphos, the secondary of the binary asteroid Didymos, and change its orbit around the primary (Cheng et al. 2018, Rivkin et al. 2021). In preparation for the late...

Lunar impact flashes are a rich source of data on highintensity, high-velocity impacts in the absence of significant atmosphere. Studies of these flashes have established that the source of much of the radiation emitted by the flash is through thermal emission from hot condensed debris produced by the impact. Here we present a quantitative forward...

The influence of mission design parameters on the deflection efficiency of hypervelocity kinetic impacts remains an open question. With the upcoming impact of NASA’s Double Asteroid Redirection Test (DART), great interest exists in understanding how to optimize the deflection of a potentially hazardous object. In this work, we investigate the influ...

NASA’s Double Asteroid Redirection Test (DART) mission performed the first ever kinetic impact to deflect an asteroid ¹ . The DART kinetic impact test artificially activated an asteroid with a hypervelocity impact, providing a unique opportunity for an extensive observing campaign to monitor the evolutionary process from the formation of the ejecta...

The Double Asteroid Redirection Test (DART) spacecraft will impact into the asteroid Dimorphos on 2022 September 26 as a test of the kinetic impactor technique for planetary defense. The efficiency of the deflection following a kinetic impactor can be represented using the momentum enhancement factor, β, which is dependent on factors such as impact...

We employ nighttime observations from the Lyman Alpha Mapping Project (LAMP) ultraviolet (UV) spectrograph onboard the Lunar Reconnaissance Orbiter to investigate the presence of condensed water ice within lunar south pole cold traps. This study incorporates LAMP observations between 2009 and 2016, which more than doubles the number of observations...

NASA’s Double Asteroid Redirection Test (DART) mission is the first full-scale test of the kinetic impactor method for asteroid deflection, in which a spacecraft intentionally impacts an asteroid to change its trajectory. DART represents an important first step for planetary defense technology demonstration, providing a realistic assessment of the...

View Video Presentation: https://doi.org/10.2514/6.2022-4267.vid The Lunar Surface Innovation Consortium (LSIC) was established in 2020 by NASA’s Space Technology Mission Directorate (Space Tech) to bring together universities, non-profit institutions, commercial companies, NASA, and other government agencies to identify the technical capabilities...

NASA's Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology. Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later Hera mission, will result in measurement of the momentum transfer efficiency accurate to ∼10% and characterization of the D...

NASA's Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology. Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later Hera mission, will result in measurement of the momentum transfer efficiency accurate to ~10% and characterization of the D...

NASA's Double Asteroid Redirection Test (DART) mission is the first full-scale test of the kinetic impactor method for asteroid deflection, in which a spacecraft intentionally impacts an asteroid to change its trajectory. DART represents an important first step for planetary defense technology demonstration, providing a realistic assessment of the...

The Double Asteroid Redirection Test (DART) spacecraft will impact into the asteroid Dimorphos on September 26, 2022 as a test of the kinetic impactor technique for planetary defense. The efficiency of the deflection following a kinetic impactor can be represented using the momentum enhancement factor, Beta, which is dependent on factors such as im...

The Double Asteroid Redirection Test (DART) is the first planetary defense test mission. It will demonstrate the kinetic impactor technique by intentionally colliding the DART spacecraft with the near-Earth asteroid Dimorphos. The main DART spacecraft is accompanied by the Italian Space Agency Light Italian CubeSat for Imaging of Asteroids (LICIACu...

Understanding how to deflect an incoming asteroid is of great importance and a focus of research undertaken internationally by the planetary defense community. Deflection of an asteroid by a kinetic impactor is one such mitigation method that has a high degree of technological maturity. In 2022, NASA’s planetary defense mission, the Double Asteroid...

NASA's Double Asteroid Redirection Test (DART) spacecraft is planned to impact the natural satellite of (65803) Didymos, Dimorphos, around 23:14 UTC on 26 September 2022, causing a reduction in its orbital period that will be measurable with ground-based observations. This test of kinetic impactor technology will provide the first estimate of the m...

Hera is a planetary defense mission under development in the Space Safety and Security Program of the European Space Agency for launch in 2024 October. It will rendezvous in late 2026 December with the binary asteroid (65803) Didymos and in particular its moon, Dimorphos, which will be impacted by NASA’s DART spacecraft on 2022 September 26 as the...

The Double Asteroid Redirection Test (DART) spacecraft will impact the moon Dimorphos of the [65803] Didymos binary in order to demonstrate asteroid deflection by a kinetic impactor. DART will measure the deflection by using ground-based telescopic observations of the orbital period change of Didymos and will carry the Light Italian CubeSat for Ima...

The DART spacecraft will impact Didymos's secondary, Dimorphos, at the end of 2022 and cause a change in the orbital period of the secondary. For simplicity, most previous numerical simulations of the impact used a spherical projectile geometry to model the DART spacecraft. To investigate the effects of alternative, simple projectile geometries on...

The DART spacecraft will impact Didymos’s secondary, Dimorphos, at the end of 2022 and cause a change in the orbital period of the secondary. For simplicity, most previous numerical simulations of the impact used a spherical projectile geometry to model the DART spacecraft. To investigate the effects of alternative, simple projectile geometries on...

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,...

Gas-rich discharges of magma produced pyroclastic vents on the lunar surface. Calculations suggest those pyroclastic vents repeatedly generated 10¹² to 10¹⁵ g of H2O and CO + CO2 for pyroclastic volumes of 10 to 500 km³ early in lunar history, particularly during the first billion years of lunar history. Some of those volatiles migrated to the luna...

NASA’s Dragonfly mission will send a rotorcraft lander to the surface of Titan in the mid-2030s. Dragonfly's science themes include investigation of Titan’s prebiotic chemistry, habitability, and potential chemical biosignatures from both water-based “life as we know it” (as might occur in the interior mantle ocean, potential cryovolcanic flows, an...

The origin of the unique south polar terrain on Enceladus is not well understood. Gravity measurements made by Cassini suggest that the ice shell is thinner at the south pole than in the north. Tides are recognized to be the ultimate energy source for the observed thermal anomaly, and are believed to regulate the activity of jets, and movement alon...

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...

The NASA Double Asteroid Redirection Test (DART) spacecraft will impact the secondary member of the [65803] Didymos binary in order to perform the first demonstration of asteroid deflection by kinetic impact. Determination of the momentum transfer to the target body from the kinetic impact is a primary planetary defense objective, using ground-base...

We present results from numerical simulations of the DART impact using the CTH shock physics code with 2D homogenous asteroid models. A design of experiments approach was used to create a run matrix of 28 simulations varying 17 different material model inputs for the impactor and target. The resulting values of the momentum transfer efficiency fact...

The Double Asteroid Redirection Test (DART) is a NASA-sponsored mission that will be the first direct test of the kinetic impactor technique for planetary defense. The DART spacecraft will impact into Didymos-B, the moon of the binary system 65803 Didymos, and the resulting period change will be measured from Earth. Impact simulations will be used...

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...

The Asteroid Impact Deflection Assessment (AIDA) collaboration is a joint ESA-NASA planetary defense collaboration that will include the first full-scale test of an asteroid deflection by kinetic impactor [1]. The AIDA collaboration comprises two independent spacecraft, the NASA-sponsored Double Asteroid Redirection Test (DART) and the ESA-led Hera...

The Planetary Impact Lab (PIL) at the Johns Hopkins University Applied Physics Laboratory (JHUAPL) includes a single-stage, compressed inert gas gun that can be used for impact experiments. The impact angle can be varied from 15° to 90° with respect to horizontal, a capability which enables oblique impacts into unconsolidated or granular materials...

The Asteroid Impact & Deflection Assessment (AIDA) targets binary near-Earth asteroid (65803) Didymos. As part of this mission, the NASA-led Double Asteroid Redirection Test (DART) will make a kinetic impactor collide with the smaller secondary of Didymos to test kinetic impact asteroid deflection technology, while the ESA-led Hera mission will eva...

The Lyman Alpha Mapping Project has detected five discrete low‐albedo anomalies in Lyman‐α (Ly‐α; 121.6 nm) nighttime reflectance maps. These anomalies reside on the nearside of the Moon within the southeastern Oceanus Procellarum and northwestern Mare Nubium, coincident with regions that have been observed to be photometrically anomalous at visibl...

This study investigates how individual large craters on Mercury (diameters of 25-200 km) can produce surface roughness over a range of baselines (the spatial horizontal scale) from 0.5 to 250 km. Surface roughness is a statistical measure of change in surface height over a baseline usually after topography has been detrended. We use root mean squar...

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...

Iapetus has a ridge along the equator that extends continuously for more than 110° in longitude. Parts of the ridge rise as much as 20 km above the surrounding terrains. Most models for the formation of this enigmatic ridge are endogenic, generally requiring the formation of a fast-spinning Iapetus with an oblate shape due to the rotation speed. Ma...

Target heterogeneities, such as cracks, faults, joints, and blocks, are known to influence impact crater morphology on planetary surfaces. We perform a preliminary investigation into how the relationship of target heterogeneity size to projectile size affects the cratering process and final crater morphology for a fixed impact velocity. We use the...

The Double Asteroid Redirection Test (DART) is a NASA mission concept currently in Phase-A study, which will provide the first full-scale test of a kinetic impactor deflection mission for planetary defense. The DART spacecraft will target the moon of Didymos (Didymos-B, or “Didymoon”) and impact the smaller body at ~6 km/s with ~500 kg mass. The ch...

Mechanics lies at the heart of many of the underpinnings of modern technological civilization: materials, infrastructure, transportation, health and security. The mechanics of dynamic failure processes also has a major bearing on the potential catastrophes that threaten civilization, including airbursts and major asteroid impacts. Recent events (su...

The south pole of the Moon is an area of great interest for exploration and scientific research because many low-lying regions are permanently shaded and are likely to trap volatiles for extended periods of time, while adjacent topographic highs can experience extended periods of sunlight. One of the goals of the Lunar Reconnaissance Orbiter (LRO)...

The Miniature Radio Frequency (Mini-RF) instrument aboard NASA's Lunar Reconnaissance Orbiter (LRO) is a hybrid dual-polarized synthetic aperture radar (SAR) that operated in concert with the Arecibo Observatory to collect bistatic radar data of the lunar nearside from 2012 to 2015. The purpose of this bistatic campaign was to characterize the rada...

We investigate the density and spatial distribution of the H2 exosphere of the Moon assuming various source mechanisms. Owing to its low mass, escape is non-negligible for H2. For high-energy source mechanisms, a high percentage of the released molecules escape lunar gravity. Thus, the H2 spatial distribution for high-energy release processes refle...

The lunar maria cover approximately 17% of the Moon's surface. Discerning discrete subsurface layers in the mare provides some constraints on thickness and volume estimates of mare volcanism. Multiple types of data and measurement techniques allow probing the subsurface and provide insights into these layers, including detailed examination of impac...

Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ∼300-kg spacec...

The upper 25-100. nm of the lunar regolith within the permanently shaded regions (PSRs) of the Moon has been demonstrated to have significantly higher surface porosity than the average lunar regolith by observations that the Lyman-α albedo measured by the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) is lower in the PSRs tha...

The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor to deflect an asteroid. AIDA is an international cooperation entering Phase A study at NASA and ESA, consisting of two mission elements: the NASA Double Asteroid Redirection Test...

A look at Orientale impact basin surface and subsurface regolith maturity with neutron, radar, near-, and thermal-infrared datasets.

Many asteroids in the Solar System exhibit unusual, linear features on their surface. The Dawn mission recently observed two sets of linear features on the surface of the asteroid 4 Vesta. Geologic observations indicate that these features are related to the two large impact basins at the south pole of Vesta, though no specific mechanism of origin...

A combination of laboratory and numerical experiments examines the role of shear localization in subsurface damage following very oblique (15-30°) hypervelocity impacts. Laboratory experiments reveal subsurface damage planes (“blades”) parallel to the impact trajectory for highly oblique impacts (15-30°), which are characterized by unique surface t...

We present strength data from dynamic failure experiments on basalt that can be used to fit existing material models or benchmark and validate impact models.

The ability to produce high-fidelity illumination and communication-visibility simulations is useful in planning lander/rover missions, and surface operations.

Dawn observed two sets of approximately linear faults on the surface of the asteroid 4 Vesta. Our experimental and numerical results show that this is a natural consequence of large, oblique impacts into a spherical, differentiated target.

The positive identification of the Rock Elm impact structure (Wisconsin, USA) and the Upheaval Dome (Utah, USA) as impact craters was complicated by a lack of distinctive shock features in the record. Low-impedance surface layers over high-impedance bedrock affect energy coupling and shock effects in the substrate; in both cases, removal of surface...

Laboratory experiments combined with numerical models suggest a possible formation mechanism for the surface troughs observed on Vesta by the Dawn spacecraft.