Category Archives: Asteroids & Comets

Dawn probe flies low over Ceres and gets dramatic views of Occator Crater

July 5, 2018 TopSpacer

The latest from the Dawn probe orbiting low over the dwarf planet Ceres in the asteroid belt:

Dawn’s Latest Orbit Reveals Dramatic New Views of Occator Crater

This mosaic of a prominent mound located on the western side of Cerealia Facula was obtained by NASA’s Dawn spacecraft on June 22, 2018 from an altitude of about 21 miles (34 kilometers). Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. Full image and caption

NASA’s Dawn spacecraft reached its lowest-ever and final orbit around dwarf planet Ceres on June 6 and has been returning thousands of stunning images and other data.

The flight team maneuvered the spacecraft into an orbit that dives 22 miles (35 kilometers) above the surface of Ceres and viewed Occator Crater, site of the famous bright deposits, and other intriguing regions. In more than three years of orbiting Ceres, Dawn’s lowest altitude before this month was 240 miles (385 kilometers), so the data from this current orbit bring the dwarf planet into much sharper focus.

These low orbits have revealed unprecedented details of the relationships between bright and dark materials in the region of Vinalia Faculae. Dawn’s visible and infrared mapping spectrometer had previously found the bright deposits to be made of sodium carbonate, a material commonly found in evaporite deposits on Earth. Last week Dawn fired its ion engine, possibly for the final time, to fly nearer Cerealia Facula, the large deposit of sodium carbonate in the center of Occator Crater.

“Acquiring these spectacular pictures has been one of the greatest challenges in Dawn’s extraordinary extraterrestrial expedition, and the results are better than we had ever hoped,” said Dawn’s chief engineer and project manager, Marc Rayman, of NASA’s Jet Propulsion Laboratory, Pasadena, California. “Dawn is like a master artist, adding rich details to the otherworldly beauty in its intimate portrait of Ceres.”

The wealth of information contained in these images, and more that are planned in the coming weeks, will help address key, open questions about the origin of the faculae, the largest deposits of carbonates observed thus far outside Earth, and possibly Mars. In particular, scientists have been wondering how that material was exposed, either from a shallow, sub-surface reservoir of mineral-laden water, or from a deeper source of brines (liquid water enriched in salts) percolating upward through fractures.

This close-up image of the Vinalia Faculae in Occator Crater was obtained by NASA’s Dawn spacecraft on June 14, 2018 from an altitude of about 24 miles (39 kilometers). Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
*Full image and caption*

And the low-altitude observations obtained with Dawn’s other instruments, a gamma ray and neutron detector and a visible and infrared mapping spectrometer, will reveal the composition of Ceres at finer scale, shedding new light on the origin of the materials found across Ceres’ surface. New gravity measurements also may reveal details of the subsurface.

“The first views of Ceres obtained by Dawn beckoned us with a single, blinding bright spot,” said Carol Raymond of JPL, Dawn’s principal investigator. “Unraveling the nature and history of this fascinating dwarf planet during the course of Dawn’s extended stay at Ceres has been thrilling, and it is especially fitting that Dawn’s last act will provide rich new data sets to test those theories.”

See more images from Dawn’s low orbits here.

Read more details about Dawn’s recent orbits in Rayman’s Dawn Journal.

The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

For a complete list of mission participants, visit: https://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-6215
gretchen.p.mccartney@jpl.nasa.gov

Dwayne Brown / JoAnna Wendel
NASA Headquarters, Washington
202-358-1726 / 202-358-1003
dwayne.c.brown@nasa.gov / joanna.r.wendel@nasa.gov

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Asteroids & Comets, Contests and Games, Living in Space

Top 10 teams selected by NASA for next stage of 3D-Printed habitat competition

July 3, 2018 TopSpacer

An announcement from NASA:

Top 10 Teams Selected in Virtual Stage of 3D-Printed Habitat Challenge

*X-Arc team illustration. X-Arc is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

NASA’s 3D-Printed Habitat Challenge is challenging teams of citizen inventors to push the state of the art of additive construction to design and build sustainable shelters for humans to live on Mars. Previous levels of the challenge have resulted in advanced habitat concepts, material compositions and printing technologies. The current stage (Phase 3: Level 1) of the multi-level contest challenges participants to prepare digital representations of physical and functional characteristics of a house on Mars using Building Information Modeling (BIM) software tools.

*Image provided by ALPHA Team, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

The habitat must comprise 1,000 square feet of living space to support four astronauts for one year and include plans for systems such as life support, mechanical and electrical, spacesuit and rover hatches, and plumbing.

*Image provided by Colorado School of Mines, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

“This stage of the competition asks the participants to design habitats that will combine shelter with critical survival systems,” said Monsi Roman, program manager for the Centennial Challenges Program. “We are asking them to look beyond the physical structure into the needs of our future explorers.”

*Image provided by Hassell & EOC, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

Eighteen teams submitted their designs on May 16, and judges have selected the top 10 teams that will continue to compete for $100,000 in prize money that will be awarded to the top five teams in July. The teams will be evaluated by a panel of subject matter experts from NASA and industry.

*Image provided by Kahn-Yates, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

The teams, listed in alphabetical order, are:

ALPHA Team – Marina Del Rey, California
Colorado School of Mines – Golden, Colorado
Hassell & EOC – San Francisco
Kahn-Yates – Jackson, Mississippi
Mars Incubator – New Haven, Connecticut
AI. SpaceFactory – New York
Northwestern University – Evanston, Illinois
SEArch+/Apis Cor – New York
Team Zopherus – Rogers, Arkansas
X-Arc – San Antonio

“There is a great breadth in use of technology and 3D-modeling skills among the judges that range from Building Information Modeling software developers to the most sophisticated applications of virtual design and construction,” said Pete Carrato, lead judge and corporate manager of Building Information Modeling at challenge sponsor Bechtel. “Each team’s submission is a view into the future of developing surface-based facilities on Mars.”

*Image provided by Mars Incubator, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

The goal of the 3D-Printed Habitat Challenge is to foster the development of technologies to manufacture a habitat using local indigenous materials with, or without, recyclable materials. The vision is that autonomous machines will someday be deployed in deep space destinations, including Mars, to construct shelters for human habitation. On Earth, these same capabilities could be used to produce affordable housing wherever it is needed or where access to conventional building materials and skills are limited.

*Image provided by AI. SpaceFactory, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

The challenge, which began in 2014, is structured in phases:

Phase 1, the Design Competition, required teams to submit architectural renderings and was completed in 2015. ($50,000 prize purse)
Phase 2, the Structural Member Competition, focused on material technologies, requiring teams to create structural components. It was completed in 2017. ($1.1 million prize purse)
Phase 3 (current), the On-Site Habitat Competition, challenges competitors to fabricate sub-scale habitats, and has five levels of competition – three construction levels and two virtual levels. For the virtual levels, teams must use BIM software to design a habitat that combines allowances for both the structure and systems it must contain. The construction levels challenge the teams to 3D-print elements of the habitat, culminating with a one-third-scale printed habitat for the final level. ($2 million prize purse)

*Image provided by Northwestern University, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

The 3D-Printed Habitat Challenge is managed through a partnership with NASA’s Centennial Challenges Program and Bradley University in Peoria, Illinois. Bradley University has partnered with sponsors Caterpillar, Bechtel and Brick & Mortar Ventures to administer the competition. NASA’s Centennial Challenges program is part of the agency’s Space Technology Mission Directorate, and is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

*Image provided by SEArch+/ Apis Cor, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

For information about the 3D-Printed Habitat Challenge, visit: http://www.nasa.gov/3DPHab

For information about NASA’s Centennial Challenges Program, visit: www.nasa.gov/winit

*Image provided by Team Zopherus, which is a top 10 finalist in the 3D-Printed Habitat Challenge Phase: 3 Level 1 competition.*

Asteroids & Comets, Events

Asteroid Day to include live webcast from Luxembourg + Hayabusa2 arrives at asteroid Ryugu

June 28, 2018 TopSpacer

Asteroid Day is this Saturday, June 30th. See the earlier posting here about this global campaign to raise awareness of the threat of asteroid impacts. Check if one of the many events planned for Asteroid day around the world is near where you live. See also updates at Asteroid Day ☄ (@AsteroidDay) | Twitter.

Here are some additional items relevant to the campaign:

** There will be a 48 hour live webcast sponsored by the European Space Agency: Asteroid Day live from Luxembourg – ESA

The world’s first 48-hour webcast about asteroids and their place in space will begin at 12:00 CEST, on Friday, 29 June 2018. Kicking off this exciting event, physicist, science advocate and former rock star Brian Cox will host the first 6-hour segment live from Luxembourg.

Brian will be joined by asteroid scientists, astronauts, rock stars and experts from around the world all in the name of Asteroid Day – the annual UN-endorsed global campaign to raise awareness about asteroids, and the risks and opportunities that they bring.

Asteroid Day takes place each year on 30 June, commemorating the 1908 Tunguska airburst over Siberia, the biggest impact event in recorded history. Since its inception, ESA has long supported the Asteroid Day initiative and plays a leading role in the global hunt for risky near-Earth objects that might one day cross our path.

** This week’s episode of the Planetary Society‘s radio program was devoted to asteroids: It’s Asteroid Week with NASA’s Planetary Defense Officer | The Planetary Society

** The Society has also opened a Kickstarter campaign called Kick Asteroid!

The Planetary Society is excited to partner with space artist and designer, Thomas Romer, and backers around the world to create Kick Asteroid—a colorful graphic poster that will illustrate the effect of past catastrophic impacts, and methods to deflect future asteroid threats. Compelling and scientifically accurate art will be created for posters and other “merch” that backers can use in their everyday lives to spread the word about planetary defense.

Asteroid and comet impacts, while not common, are very real threats. By backing this project, you can help spread the word about asteroid defense. You will be doing your part to protect the people of Earth from a devastating impact.

** Appropriately enough, the Japanese space agency’s Hayabusa2 probe arrived this week at the asteroid Ryugu after a three and a half year voyage from earth: Hayabusa2 Rendezvous with Ryugu – JAXA

On June 27, 2018, JAXA operated Hayabusa2 chemical propulsion thrusters for the spacecraft’s orbit control.*

The confirmation of the Hayabusa2 rendezvous made at 9:35 a.m. (Japan Standard Time, JST) is based on the following data analyses;

・The thruster operation of Hayabusa2 occurred nominally

・The distance between Hayabusa2 and Ryugu is approximately 20 kilometers

・Hayabusa2 is able to maintain a constant distance to asteroid Ryugu

・The status of Hayabusa2 is normal

The probe will spend a year and half studying the diamond shaped asteroid and four small landers will be deployed onto the surface. In addition, the probe will grab a sample of the surface and return it to earth in December 2020.

A comparison of Ryugu to other asteroids visited by space probes: Hayabusa2 arrived at Ryugu, so I can make comparisons of asteroid scales! | The Planetary Society.

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Asteroids & Comets, Astronomy, Space Science

Hubble: Interstellar visitor ‘Oumuamua leaving faster than expected

June 27, 2018 TopSpacer

The interstellar object that passed through the solar system continues to provide surprises:

Hubble sees `Oumuamua getting a boost
New results indicate interstellar nomad is a comet

`Oumuamua, the first interstellar object discovered in the Solar System, is moving away from the Sun faster than expected. This anomalous behaviour was detected using the NASA/ESA Hubble Space Telescope in cooperation with ground-based telescopes. The new results suggest that `Oumuamua is most likely a comet and not an asteroid. The discovery appears in the journal Nature.

This diagram shows the orbit of the interstellar object ‘Oumuamua as it passes through the Solar System. It shows the predicted path of ‘Oumuamua and the new course, taking the new measured velocity of the object into account. ‘Oumuamua passed the distance of Jupiter’s orbit in early May 2018 and will pass Saturn’s orbit January 2019. It will reach a distance corresponding to Uranus’ orbit in August 2020 and of Neptune in late June 2024. In late 2025 ‘Oumuamua will reach the outer edge of the Kuiper Belt, and then the heliopause — the edge of the Solar System — in November 2038.

`Oumuamua — the first interstellar object discovered within our Solar System — has been the subject of intense scrutiny since its discovery in October 2017 [1]. Now, by combining data from the NASA/ESA Hubble Space Telescope, the Canada-France-Hawaii Telescope, ESO’s Very Large Telescope and the Gemini South Telescope, an international team of astronomers has found that the object is moving faster than predicted. The measured gain in speed is tiny and `Oumuamua is still slowing down because of the pull of the Sun — just not as fast as predicted by celestial mechanics.

The team, led by Marco Micheli (European Space Agency) explored several scenarios to explain the faster-than-predicted speed of this peculiar interstellar visitor. The most likely explanation is that `Oumuamua is venting material from its surface due to solar heating — a behaviour known as outgassing [2]. The thrust from this ejected material is thought to provide the small but steady push that is sending `Oumuamua hurtling out of the Solar System faster than expected — as of 1 June, it is travelling with about 114 000 kilometres per hour.

Such outgassing is a typical behaviour for comets and contradicts the previous classification of `Oumuamua as an interstellar asteroid.

“We think this is a tiny, weird comet,” comments Marco Micheli. “We can see in the data that its boost is getting smaller the farther away it travels from the Sun, which is typical for comets.”

Usually, when comets are warmed by the Sun they eject dust and gas, which form a cloud of material — called a coma — around them, as well as the characteristic tail. However, the research team could not detect any visual evidence of outgassing.

“We did not see any dust, coma, or tail, which is unusual,” explains co-author Karen Meech (University of Hawaii, USA) who led the discovery team’s characterisation of `Oumuamua in 2017. “We think that ‘Oumuamua may vent unusually large, coarse dust grains.”

The team speculated that perhaps the small dust grains adorning the surface of most comets eroded during `Oumuamua’s journey through interstellar space, with only larger dust grains remaining. A cloud of these larger particles would not be bright enough to be detected by Hubble.

Not only is `Oumuamua’s hypothesised outgassing an unsolved mystery, but also its interstellar origin. The team originally performed the new observations on `Oumuamua to exactly determine its path which would have probably allowed it to trace the object back to its parent star system. The new results means it will be more challenging to obtain this information.

“The true nature of this enigmatic interstellar nomad may remain a mystery,” concludes team member Olivier Hainaut (European Southern Observatory, Germany). “`Oumuamua’s recently-detected gain in speed makes it more difficult to be able to trace the path it took from its extrasolar home star.”

This artist’s impression shows the first interstellar object discovered in the Solar System, `Oumuamua. Observations made with the NASA/ESA Hubble Space Telescope and others show that the object is moving faster than predicted while leaving the Solar System. Researchers assume that venting material from its surface due to solar heating is responsible for this behaviour. This outgassing can be seen in this artist’s impression as a subtle cloud being ejected from the side of the object facing the Sun. As outgassing is a behaviour typical for comets, the team thinks that `Oumuamua’s previous classification as an interstellar asteroid has to be corrected. [Higher res images]

Notes

[1]`Oumuamua, pronounced “oh-MOO-ah-MOO-ah”, was first discovered using the Pan-STARRS telescope at the Haleakala Observatory, Hawaii. Its name means “a messenger from afar, arriving first” in Hawaiian, and reflects its nature as the first known object of interstellar origin to have entered the Solar System.

[2] The team tested several hypotheses to explain the unexpected change in speed. They analysed whether solar radiation pressure, the Yarkovsky effect, or friction-like effects could explain the observations. It was also checked whether the gain in speed could have been caused by an impulse event (such as a collision), by `Oumuamua being a binary object or by `Oumuamua being a magnetised object. Also, the unlikely theory that `Oumuamua is an interstellar spaceship was rejected: the smooth and continuous change in speed is not typical for thrusters and the object is tumbling on all three axes, speaking against it being an artificial object.

Asteroids & Comets, Space Science

NASA DART and ESA Hera to study deflecting asteroids via spacecraft impact

June 26, 2018 TopSpacer

ESA and NASA are testing defenses against an asteroid threat:

Earth’s first mission to a binary asteroid,
for planetary defence

Hera is the European contribution to an ESA-NASA double-spacecraft mission intended to test whether a kinetic deflection technique can be used to shift the orbit of an asteroid. Target of the mission is a double asteroid system, called Didymos, which will come a comparatively close 11 million km to Earth in 2022. The 800-m diameter main body is orbited by a 170-m moon, informally called ‘Didymoon’. In 2022 NASA will first perform a kinetic impact on the smaller of the two bodies, then Hera will follow-up with a detailed post-impact survey that will turn this grand-scale experiment into a well-understood and repeatable planetary defence technique.

25 June 2018: Planning for humankind’s first mission to a binary asteroid system has entered its next engineering phase. ESA’s proposed Hera mission would also be Europe’s contribution to an ambitious planetary defence experiment.

Named for the Greek goddess of marriage, Hera would fly to the Didymos pair of Near-Earth asteroids: the 780 m-diameter mountain-sized main body is orbited by a 160 m moon, informally called ‘Didymoon’, about the same size as the Great Pyramid of Giza.

“Such a binary asteroid system is the perfect testbed for a planetary defence experiment but is also an entirely new environment for asteroid investigations. Although binaries make up 15% of all known asteroids, they have never been explored before, and we anticipate many surprises,”

explains Hera manager Ian Carnelli.

“The extremely low-gravity environment also presents new challenges to the guidance and navigation systems. Fortunately we can count on the unique experience of ESA’s Rosetta operations team which is an incredible asset for the Hera mission.”

The smaller Didymoon is Hera’s main focus: the spacecraft would perform high-resolution visual, laser and radio science mapping of the moon, which will be the smallest asteroid visited so far, to build detailed maps of its surface and interior structure.

By the time Hera reaches Didymos, in 2026, Didymoon will have achieved historic significance: the first object in the Solar System to have its orbit shifted by human effort in a measurable way.

A NASA mission called the Double Asteroid Redirection Test, or DART, is due to collide with it in October 2022. The impact will lead to a change in the duration of Didymoon’s orbit around the main body. Ground observatories all around the world will view the collision, but from a minimum distance of 11 million km away.

“Essential information will be missing following the DART impact – which is where Hera comes in,” adds Ian. “Hera’s close-up survey will give us the mass of Didymoon, the shape of the crater, as well as physical and dynamical properties of Didymoon.

“This key data gathered by Hera will turn a grand but one-off experiment into a well-understood planetary defence technique: one that could in principle be repeated if we ever need to stop an incoming asteroid.”

The traditional method of estimating the mass of a planetary body is to measure its gravitational pull on a spacecraft. That is not workable within the Didymos system: Didymoon’s gravitational field would be swamped by that of its larger partner.

*Hera uses infrared to scan impact crater.*

Instead, Hera imagery will be used to track key landmarks on the surface on the bigger body, ‘Didymain’, such as boulders or craters. By measuring the ‘wobble’ Didymoon causes its parent, relative to the common centre of gravity of the overall two-body system, its mass could be determined with an accuracy over 90%.

Hera will also measure the crater left by DART to a resolution of 10 cm, accomplished through a series of daring flybys, giving insight into the surface characteristics and internal composition of the asteroid.

“Hera benefits from more than five years of work put into ESA’s former Asteroid Impact Mission,” comments Ian. “Its main instrument is a replica of an asteroid imager already flying in space – the Framing Camera used by NASA’s Dawn mission as it surveys Ceres, which is provided by the German Aerospace Center, DLR.

“It would also carry a ‘laser radar’ lidar for surface ranging, as well as a hyperspectral imager to characterise surface properties. In addition, Hera will deploy Europe’s first deep space CubeSats to gather additional science as well as test advanced multi-spacecraft intersatellite links.”

NASA’s DART mission meanwhile has passed its preliminary design review and is about to enter its ‘Phase C’ detailed design stage.