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On Sept. 26th, 2022, NASA’s Double Asteroids Redirect Test (DART) collided with Dimorphos, the small moonlet orbiting the larger asteroid Didymos. In so doing, the mission successfully demonstrated a proposed strategy for deflecting potentially hazardous asteroids (PHAs) – the kinetic impact method. By October 2026, the ESA’s Hera mission will rendezvous with the double-asteroid system and perform a detailed post-impact survey of Dimorphos to ensure that this method of planetary defense can be repeated in the future.

However, while the kinetic method could successfully deflect asteroids so they don’t threaten Earth, it could also create debris that might reach Earth and other celestial bodies. In a recent study, an international team of scientists explored how this impact test also presents an opportunity to observe how this debris could someday reach Earth and Mars as meteors. After conducting a series of dynamic simulations, they concluded that the asteroid ejecta could reach Mars and the Earth-Moon system within a decade.

The research team was led by Dr. Eloy Peña-Asensio, a Research Fellow with the Deep-space Astrodynamics Research and Technology (DART) group at the Polytechnic Institute of Milan. He was joined by colleagues from the Autonomous University of Barcelona, the Institute of Space Sciences (ICE-CSIS), part of the Spanish National Research Council, the Catalonia Institute of Space Studies (IEEC), and the European Space Agency (ESA). The paper that details their findings recently appeared online and has been accepted for publication by The Planetary Science Journal.

For their study, Peña-Asensio and his colleagues relied on data obtained by the Light Italian CubeSat for Imaging of Asteroids (LICIACube), which accompanied the DART mission and witnessed the kinetic impact test. This data allowed the team to constrain the initial conditions of the ejecta, including its trajectories and velocities – ranging from a few tens of meters per second to about 500 m/s (1800 km/h; ~1120 mph). The team then used the supercomputers at NASA’s Navigation and Ancillary Information Facility (NAIF) to simulate what will become of the ejecta.

These simulations tracked the 3 million particles created by the DART mission’s impact with Dimorphos. As Peña-Asensio told Universe Today via email:

“LICIACube provided crucial data on the shape and direction of the ejecta cone immediately following the collision. In our simulation, the particles ranged in size from 10 centimeters to 30 micrometers, with the lower range representing the smallest sizes capable of producing observable meteors on Earth with current technology. The upper range was limited by the fact that only ejected centimeter-sized fragments were observed.”

Their results indicated that some of these particles would reach Earth and Mars within a decade or more, depending on how fast they traveled after the impact. For example, particles ejected at velocities below 500 m/s could reach Mars in about 13 years, whereas those ejected at velocities exceeding 1.5 km/s (5,400 km/h; 3,355 mph) could reach Earth in as little as seven years. However, their simulations indicated that it will likely be up to 30 years before any of this ejecta is observed on Earth.

This illustration shows the ESA’s Hera spacecraft and its two CubeSats at the binary asteroid Didymos. Credit: ESA

“However, these faster particles are expected to be too small to produce visible meteors, based on early observations,” said Peña-Asensio. “Nevertheless, ongoing meteor observation campaigns will be critical in determining whether DART has created a new (and human-created) meteor shower: the Dimorphids. Meteor observing campaigns in the coming decades will have the last word. If these ejected Dimorphos fragments reach Earth, they will not pose any risk. Their small size and high speed will cause them to disintegrate in the atmosphere, creating a beautiful luminous streak in the sky.”

Peña-Asensio and his colleagues also note that future Mars observation missions will have the opportunity to witness Martian meteors as fragments of Didymos burn up in its atmosphere. In the meantime, their study has provided the potential characteristics these and any future meteors burning up in our atmosphere will have. This includes direction, velocity, and the time of the year they will arrive, allowing any “Dimorphids” to be clearly identified. This is part of what makes the DART mission and its companion missions unique.

In addition to validating a key strategy for planetary defense, DART has also provided an opportunity to model how ejecta caused by impacts could someday reach Earth and other bodies in the Solar System. As Michael Küppers, the Project Scientist of the ESA’s Hera mission and co-author of the paper, told Universe Today via email:

“A unique aspect of the DART mission is that it is a controlled impact experiment, i.e., an impact where the impactor properties (size, shape, mass, velocity) are accurately known. Thanks to the Hera mission, we will also know the target properties well, including those of the DART impact site. Data about the ejecta came from LICIACube and earth-based observations after the impact. There is probably no other impact on a planetary scale with that much information about the impactor, the target, and the ejecta formation and early development. This allows us to test and improve our models and scaling laws of the impact process and ejecta evolution. Those data provide the input data (source location, size, and velocity distribution) used by the ejecta evolution models.”

Further Reading: arXiv

The post Debris from DART could Hit Earth and Mars Within a Decade appeared first on Universe Today.

While a NASA probe heads for an asteroid known as Psyche, telescopes have been probing it to prepare for the arrival. Data from the James Webb Space Telescope has found something quite unexpected on the surface – hydrated molecules and maybe even water! The origin of the water is cause for much speculation, maybe it came from under the surface or from chemical interactions with the solar wind! 

Asteroid Psyche was discovered in 1852 by the Italian astronomer Annibale de Gasparis. It was named after the Greek goddess of the soul who was born mortal and married Eros. It measures 225 km across and is one of the most massive objects in the asteroid belt between Mars and Jupiter. Most of the asteroids in the belt are composed of rock and ice but Psyche seems to be different being largely composed of metals, perhaps the exposed core of a protoplanet that lost its outer layers. Psyche is of immense interest to study because it provides an opportunity to study planetary cores which are usually inaccessible. 

Illustration of the metallic asteroid Psyche. Credit: Peter Rubin/NASA/JPL-Caltech/ASU

Aptly named Psyche, the probe launched by NASA has already started its 3.5 billion km journey to the asteroid, due to arrive in August 2029. With its solar panels deployed, the probe measures 25 metres by 7.3 metres, about the size of a tennis court. It has a mass of 2,747 kg and is powered by five solar panel arrays. Once arrived at Psyche they can generate about 3 kilowatts of power.

While the probe is enroute, telescopes on Earth and in space have been exploring Psyche. Observations in different wavelengths of light have provided information that will aid and support the data collected by the Psyche spacecraft. The study was led by Dr. Stephanie Jarmak from the Southwest Research Institute and it was their observations that confirmed the hydroxyl molecules on the surface. 

Image of NASA engineers preparing the Psyche spacecraft for launch within a clean room at the Astrotech Space Operations Facility located near the NASA Kennedy Space Center. Psyche is scheduled to launch in October 2023 on a SpaceX Falcon Heavy rocket from historic Launch Complex 39A at Kennedy. (Credit: NASA/Ben Smegelsky)

The data, which was collected using the James Webb Space Telescope revealed the telltale signs of hydroxyl but stopped short of explaining where they came from. There are two possible explanations and we can look to the origin of asteroids to understand them. They are the leftovers from the formation of planets and their make up is determined by the location in the solar nebula from which they formed. If the hydroxyl formed locally without interference from external process then it might suggest that Psyche is not a planetary core remnant.  It might be that Psyche simply formed at a distance that volatile compounds like water condense to form solids like ice before migrating. 

An alternative model explains the variability of the molecule distribution across the surface. This might indicate that impacts from carbonaceous chondrites (like the meteorites often found on Earth) could have provided the water molecules that have been observed. 

It seems that for now, we will have to wait until the arrival of the Psyche spacecraft in 2029 to unravel the mystery. If we can get a better understanding of the origin of the asteroid Psyche it will help us to learn more about the distribution of elements in the nebula that the planets formed from. In particular, understanding more about the distribution of water will help us to develop a better insight to the origins of life. 

Source : SwRI-Ked Team Finds Evidence of Hydration on Psyche

The post There Might Be Water on the Surface of the Metal Asteroid Psyche appeared first on Universe Today.

Around 25 per cent of the world’s population has intestinal parasite infections – these could hinder the effectiveness of covid-19 vaccines, according to research in mice

Who are we? Why are we here? We are stardust, the result of chemistry occurring throughout vast clouds of interstellar gas and dust. To better understand how that chemistry could create prebiotic molecules, researchers investigated the role of low-energy electrons created as cosmic radiation traverses through ice particles. Their findings may also inform medical and environmental applications on our home planet.

Who are we? Why are we here? We are stardust, the result of chemistry occurring throughout vast clouds of interstellar gas and dust. To better understand how that chemistry could create prebiotic molecules, researchers investigated the role of low-energy electrons created as cosmic radiation traverses through ice particles. Their findings may also inform medical and environmental applications on our home planet.

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