Daniel Scheeres News

Scheeres joins ESA’s Hera asteroid mission

Anonymous — Wed, 03 Jul 2024 15:08:11 +0000

Scheeres joins ESA’s Hera asteroid mission Anonymous (not verified) Wed, 07/03/2024 - 09:08

Dan Scheeres has been named a NASA participating scientist on the European Space Agency’s Hera mission.

Scheeres, a distinguished professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at the �鶹ӰԺ, is one of 12 individuals announced by NASA to join the space probe mission, which is scheduled to launch in October 2024.

Hera will study the binary asteroid system Didymos, including the moonlet Dimorphos, which was impacted by NASA’s DART (Double Asteroid Redirection Test) spacecraft on Sept. 26, 2022. The objectives of DART and Hera collectively aim to validate the kinetic impact method as a technology to deflect an asteroid on a collision course with Earth, if one is ever discovered, and to learn more about the near-Earth asteroids that are the source of this natural hazard.

“The Smead Department was heavily involved with the DART mission, and Hera is really the culmination of that project. My overall focus will be on interpreting the pictures we obtain of the Didymos binary asteroid system to better understand the orbit and spins of the two bodies about each other, and to understand what the surface environment is like,” Scheeres said.

Scheeres is a National Academy of Engineering member, recognized for pioneering work on the motion of bodies in strongly perturbed environments such as near asteroids and comets.

Hera is scheduled to arrive at the Didymos/Dimorphos binary asteroid system at the end of 2026, where it will gather otherwise unobtainable data about the mass and makeup of both bodies and assess the changes caused by the DART spacecraft’s kinetic impact.

“There are many aspects of this system that don't seem to make sense, so puzzling out these different issues will be an exciting and exhilarating experience,” Scheeres said. “The Hera mission will be able to take crucial measurements that will determine how effective the DART impact was in moving the secondary asteroid Dimorphos.”

The goal of NASA’s Hera Participating Scientist Program is to support scientists at U.S. institutions to participate on the Hera mission and address outstanding questions in planetary defense and near-Earth asteroid science. The participating scientists will become Hera science team members during their 5-year tenure with the mission.

DART was the first flight mission from NASA’s Planetary Defense Coordination Office, which oversees the agency’s ongoing efforts in planetary defense. International participation in DART and Hera, including the Hera Participating Scientist Program, has been enabled by an ongoing worldwide collaboration in the planetary defense research community known as the Asteroid Impact and Deflection Assessment.

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Asteroid named for CU �鶹ӰԺ aerospace grad student

Anonymous — Tue, 13 Feb 2024 16:02:37 +0000

Asteroid named for CU �鶹ӰԺ aerospace grad student Anonymous (not verified) Tue, 02/13/2024 - 09:02

Jeff Zehnder

Asteroids with CU �鶹ӰԺ Connections

Meyer is not the first person at CU �鶹ӰԺ to have an asteroid named after them! There are currently three other researchers in Smead Aerospace who also have the distinction:

Distinguished Professor Dan Scheeres

Asteroid: (8887) Scheeres

Associate Professor Jay McMahon

Asteroid: (46829) McMahon

Research Associate Paul Sánchez

Asteroid: (20882) Paulsánchez

Above: Alex Meyer
Header Image: Diagram showing the orbital path of asteroid (33974) Alexmeyer.

PhD student played key role on NASA’s DART Mission

Alex Meyer is an astrodynamics expert, engineer, PhD student, and now, a part of the night sky. The International Astronomical Union has officially named an asteroid after him.

Asteroid 2000 ND17 is now (33974) Alexmeyer.

“It’s pretty cool and quite an honor,” Meyer said. “You look around at other asteroids and the people they’re named after; it’s very good company to be in.”

As a fifth year aerospace PhD student at the �鶹ӰԺ, Meyer is being recognized for fundamental research he conducted on the dynamics of binary asteroid systems and how they are affected by close planetary flybys.

His work is part of NASA's Double Asteroid Redirection Test (DART) mission, which in 2022 intentionally crashed a space probe into an orbiting binary asteroid to study deflection technology.

“Alex’s research was fundamentally relevant to the DART mission,” said Dan Scheeres, a distinguished professor of aerospace at CU �鶹ӰԺ and Meyer’s advisor.

Scheeres nominated Meyer for the naming honor.

“He played such a big role and the work he provided was really unique. He developed simulations on what would happen to this asteroid after the impact and provided advice on the science to other engineers,” Scheeres said.

The naming is made all the more impressive by the fact that Meyer’s contributions began somewhat unexpectedly.

“When I started at CU �鶹ӰԺ I was interested in orbital mechanics, but was playing around in a couple different areas of research. Then a more senior grad student who had responsibility with DART was leaving, and Dan asked if I could take over,” Meyer said.

He dove in with aplomb.

“Binary asteroids gave me the opportunity to work on cutting edge missions and I just kept finding new and interesting things to study,” Meyer said. “The dynamics of these binary systems can be quite complicated. Asteroids don’t look like spheres; they’re weird shapes and their orbits are quite close together. So the gravity between them becomes really complex.”

A personal ambition toward advanced research and analysis is what drove Meyer’s interest in graduate school and specifically CU �鶹ӰԺ.

“This is one of the best astrodynamics schools in the country, and being able to apply myself on these real world problems as a PhD student is a great opportunity. I was one of the main dynamicists on the mission,” Meyer said.

The research has become a key part of his PhD thesis. Meyer intends to graduate this summer and is currently at work on his dissertation. After graduation, he hopes to work full time in a research laboratory.

Meyer’s asteroid orbits as part of the asteroid belt between Mars and Jupiter. Approximately 7 km (4.35 mi) in diameter, it was originally spotted in 2000. It is possible to see with a large personal telescope, but it requires at least an 18” mirror, and so is best viewed from an observatory.

Alex Meyer is an astrodynamics expert, engineer, PhD student, and now, a part of the night sky. The International Astronomical Union has officially named an asteroid after him. Asteroid 2000 ND17 is now...

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Second life for the Janus spacecraft?

Anonymous — Fri, 02 Feb 2024 18:01:53 +0000

Second life for the Janus spacecraft? Anonymous (not verified) Fri, 02/02/2024 - 11:01

Jeff Zehnder

Space News is highlighting a potential new mission for the mothballed Janus spacecrafts.

Dan Scheeres, a distinguished professor of aerospace at the �鶹ӰԺ, was principal investigator on the Janus mission.

Designed and built to launch as a secondary payload on the Psyche mission in 2022, the mission was canceled after delays with Psyche.

Now, a new mission could resurrect the spacecrafts. The Space News feature highlights potential for the crafts to be used to rendezvous with the Apophis asteroid in 2029.

Scheeres is quoted in the piece.

Several options are available, he said, with trajectories that take the spacecraft out to the Earth-sun L-2 Lagrange point followed by a lunar flyby to set up an Apophis flyby “well in advance” of the asteroid’s close approach to the Earth. “It’s still in our wheelhouse,” he said.

The Space News piece discusses obstacles -- funding and otherwise -- to the idea, but said Scheeres will be participating in an upcoming NASA gathering to discuss potential for the mission.

Read the full piece at SpaceNews...

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CU �鶹ӰԺ leading $5 million multi-university project to advance the space economy

Anonymous — Tue, 03 Oct 2023 17:37:18 +0000

CU �鶹ӰԺ leading $5 million multi-university project to advance the space economy Anonymous (not verified) Tue, 10/03/2023 - 11:37

Jeff Zehnder

STARLIT - univerSiTy spAce stRategic technoLogy InitiaTive

University Partners

CU �鶹ӰԺ (Lead Institution)
- Marcus Holzinger (Principal Investigator)
- Jay McMahon
- Daniel Scheeres
- CU �鶹ӰԺ Center for National Security Initiatives
Texas A&M University
- K. Terry Alfriend (Deputy Principal Investigator)
- Suman Chakravorty
- Kyle DeMars
University of Texas Austin
- Brandon Jones
- Moriba Jah
- Ryan Russell
Purdue University
- Kathleen Howell
University at Buffalo
- John L. Crassidis
- Moises Sudit
Georgia Institute of Technology
- Karen M. Feigh

Industry Advisory Board

Advanced Space
Ball Aerospace
Emergent Space Technologies
Johns Hopkins University Applied Physics Laboratory
Kayhan Space
KBR
L3Harris
Lockheed Martin
Maxar
Northrop Grumman
Trusted Space

The space economy is booming, and the �鶹ӰԺ is at the forefront of a major federal funding initiative aimed at expanding science and engineering knowledge and workforce development for projects centered on operations Beyond Geostationary Orbit (xGEO) and Space Domain Awareness (SDA).

Leading this endeavor is Marcus Holzinger, a J. Negler Endowed Professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. He is heading a new, $5 million, up to five-year research award with an option for an additional $1 million and further follow on funding.

The grant will go toward an array of diverse activities, including lunar-focused astrodynamics and sensing research, conflict simulation, and expanding workforce pathways related to the space workforce.

It may sound like science fiction, but NASA, the U.S. Space Force (USSF), and a rapidly growing number of private businesses envision significant potential for economic development on and around the Moon.

“There is a massive growth forecast in the space economy over the next 10-15 years; it’s going to double and then double again,” said Holzinger.

Called STARLIT, the grant brings together an array of leading aerospace universities, including CU �鶹ӰԺ, Purdue, Georgia Tech, Texas A&M, University of Texas Austin, and the University at Buffalo as well as an industry advisory board of 11 aerospace firms.

“We’re bringing together all the right people. These collaborators are experts in astrodynamics, space traffic management, data fusion, and cognitive engineering. It’s really an amazing team,” Holzinger said.

An additional CU �鶹ӰԺ partner is the university’s Center for National Security Initiatives. NSI will facilitate sponsor events and engagement, monitor cost-performance objectives, and identify adjacent defense opportunities to further advance the research and expand its national security footprint.

The project is being administered by the Universities Space Research Association and funded by the U.S. Space Force and the Air Force Research Laboratory (AFRL).

Growing People

One focus of the funding opportunity is dramatically expanding the space workforce. The funding aims to create new graduate education pathways, including summer research initiatives with minority serving institutions, student employment and mentorship opportunities, and internship programs through community colleges.

“We need more folks to go into astrodynamics. CU �鶹ӰԺ and other universities have increased enrollment, but there are probably two job openings for every person in these core areas,” Holzinger said. “How do we help direct students into these careers?”

Expanding Research

The grant will also boost efforts on orbital propagation and mission design for satellites and space vehicles that travel beyond low Earth orbit, including to the Moon.

Although the United States made multiple successful landings on the Moon, the drive for a space economy demands scalable toolsets and technology transfer to simplify the process and improve safety, according to Dan Scheeres, a distinguished professor of aerospace at CU �鶹ӰԺ and co-investigator on the grant.

“Over the last decade there have been significant advances in our understanding of the dynamics and navigation of spacecraft in cis-lunar space. However, many of these advances have not made their way into the operational tools that USSF and commercial operators use. This research is focused on transitioning these tools and concepts into some of the day-to-day operations and capabilities for cis-lunar space,” Scheeres said.

Conflict Simulations

A major reason for expanded interest in the Moon is the discovery of frozen water at the Lunar South Pole. It represents a potential game changer for space exploration, making it much easier to sustain human life on the Moon and beyond.

That creates new opportunities and challenges. With more nations and businesses targeting the Moon for economic development, the potential for conflict between them is growing. As part of the grant’s research focus, the team aims to develop new decision-making tools to avoid conflict and strategic surprise.

“This is about nation states and companies interacting and competing diplomatically and economically,” Holzinger said. “With the resources we’ve now discovered on the Moon, these are important questions that have never been explored. We’re going to learn a lot.”

As human and robotic space missions continue to expand, Holzinger is excited about the opportunities the grant presents to positively contribute to the future of science and engineering.

“This isn’t just sending people to the Moon, but engaging in economic activity there,” Holzinger said. “The first space race was about national pride and prestige. This second space race is about durable, sustainable human economic activity there long term.”

The space economy is booming, and the �鶹ӰԺ is at the forefront of a major federal funding initiative aimed at expanding...

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Talking the Janus asteroid mission with SpaceNews.com

Anonymous — Fri, 27 Jan 2023 17:34:00 +0000

Talking the Janus asteroid mission with SpaceNews.com Anonymous (not verified) Fri, 01/27/2023 - 10:34

Dan Scheeres was interviewed by SpaceNews.com on progress and setbacks with the Janus asteroid probe mission.

Scheeres, a distinguished professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences, is the the principal investigator for the project, which was planned to launch two probes on asteroid rendezvous missions.

Unfortunately, a delay in the launch of the rocket Janus was to ride on means the probes will no longer be able to reach their intended destination.

Read the full piece and the prospect for Janus' future at SpaceNews.com...

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CU �鶹ӰԺ lands $5.5 million Air Force project to advance orbital and AI research

Anonymous — Tue, 23 Aug 2022 15:01:46 +0000

CU �鶹ӰԺ lands $5.5 million Air Force project to advance orbital and AI research Anonymous (not verified) Tue, 08/23/2022 - 09:01

Jeff Zehnder

The waning gibbous Moon above the Earth's horizon over the Atlantic Ocean.

A team of �鶹ӰԺ researchers is embarking on a major research project that will advance our understanding of orbital mechanics and monitoring, artificial intelligence, and hypersonics.

Led by Marcus Holzinger, an associate professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences, the group has signed a $5.54 million, five-year cooperative agreement with the Air Force Research Laboratory to advance science and monitoring for next generation of space vehicles – particularly those that will travel beyond low Earth orbit to the Moon.

“These are really complex multi-domain applications in the defense world and we’re bringing together preeminent researchers to tackle these problems,” Holzinger said. “There’s a real opportunity to make important advances.”

The cooperative agreement represents a significant expansion of the relationship between Smead Aerospace and the Air Force Research Laboratory’s Space Vehicles Directorate. Holzinger said the project will include ongoing collaboration and could evolve and change as the research develops.

“The region in, around, and affected by the Earth-Moon-Sun system has drastically increased in commercial activity and Department of Defense mission relevance over the last few years,” Holzinger said. “There are more and more missions going to the Moon – not just our missions but India, China, and Europe as well. That means there needs to be some sensible tracking and detection of what’s going on out there and this project addresses that crucial need directly.”

Holzinger said this area, called space domain awareness, is important for national defense and to ensure spaceflight safety and responsible behavior. Currently, the Air Force maintains tracking networks to actively catalog space vehicles to avoid collisions. However, these systems only work for spacecraft orbiting the Earth, not the Moon, and growing traffic in orbit around Earth has made collision avoidance increasingly complicated.

NASA Orbital Debris Program illustration of satellites and space debris in low Earth orbit.

To address this, the team will work to develop a framework for spacecraft to make autonomous maneuvering decisions without human input by using artificial intelligence both for collision avoidance and to execute complex tasks, said Morteza Lahijanian, an assistant professor in Smead Aerospace and a member of the project team.

“This research will teach us how to go about designing safe autonomy for complex systems, especially in a setting where multiple space vehicles need to cooperate,” said Lahijanian. “This research can lead to designing fully autonomous spacecraft that we can trust, and would eliminate the role of humans who are typically the source of errors in the design or execution of missions.”

The work also aims to better understand the unique orbital dynamics surrounding the Moon to help future researchers and commercial projects, said Holzinger.

“We’re really interested in what sorts of repeating natural orbits are best for various applications and what are the best ways to get to and from those orbits,” Holzinger said. “We want to develop design tools so mission engineers can more easily answer these questions. Right now there are not enough experts that can do that work to meet the need.”

A third goal for the cooperative agreement aims to advance the science of hypersonic vehicles. Hypersonics is an active area of research around the world for national defense purposes.

During hypersonic flight, a vehicle and the gasses surrounding it can reach thousands of degrees, triggering chemical reactions. The team hopes to develop and validate models that will ensure hypersonic vehicle signatures, heat flux, and materials response can be predicted with minimal uncertainty.

In addition to Holzinger and Lahijanian, additional CU �鶹ӰԺ faculty partners include professors Natasha Bosanac, Tim Minton, Hanspeter Schaub, and Dan Scheeres.

A team of �鶹ӰԺ researchers is embarking on a major research project that will advance our understanding of orbital mechanics and monitoring, artificial intelligence, and hypersonics. Led by Marcus Holzinger, an...

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Scientists peer inside an asteroid

Anonymous — Fri, 09 Oct 2020 15:38:46 +0000

Scientists peer inside an asteroid Anonymous (not verified) Fri, 10/09/2020 - 09:38

New findings from NASA’s OSIRIS-REx mission suggest that the interior of the asteroid Bennu could be weaker and less dense than its outer layers—like a crème-filled chocolate egg flying though space.

The results appear in a study published today in the journal Science Advances and led by the �鶹ӰԺ’s OSIRIS-REx team, including professors Daniel Scheeres and Jay McMahon. The findings could give scientists new insights into the evolution of the solar system’s asteroids—how bodies like Bennu transform over millions of years or more.

OSIRIS-REx rendezvoused with Bennu, an asteroid orbiting the sun more than 200 million miles from Earth, in late 2018. Since then, the spacecraft, built by Colorado-based Lockheed Martin, has studied the object in more detail than any other asteroid in the history of space exploration.

So far, however, one question has remained elusive: What’s Bennu like on the inside?

Scheeres, McMahon and their colleagues on the mission’s radio science team now think that they have an answer—or at least part of one. Using OSIRIS-REx’s own navigational instruments and other tools, the group spent nearly two years mapping out the ebbs and flows of Bennu’s gravity field. Think of it like taking an X-ray of a chunk of space debris with an average width about the height of the Empire State Building.

Top: Diagram of the orbit of Bennu in relation to Earth and other planets; bottom: Particles ejected from the surface of Bennu. (Credits: NASA/Goddard/University of Arizona/Lockheed Martin)

“If you can measure the gravity field with enough precision, that places hard constraints on where the mass is located, even if you can’t see it directly,” said Andrew French, a coauthor of the new study and a former graduate student at CU �鶹ӰԺ, now at NASA’s Jet Propulsion Laboratory (JPL).

What the team has found may also spell trouble for Bennu. The asteroid’s core appears to be weaker than its exterior, a fact that could put its survival at risk in the not-too-distant future.

“You could imagine maybe in a million years or less the whole thing flying apart,” said Scheeres, a distinguished professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences.

Evolution of asteroids

Of course, that’s part of the fun of studying asteroids. Scheeres explained that Bennu belongs to a class of smaller bodies that scientists call “rubble pile” asteroids—which, as their name suggests, resemble loosely held-together mounds of debris.

Asteroids also change over time more than people think.

“None of them have sat out there unchanging since the dawn of the solar system,” Scheeres said. “They’re being changed by things like sunlight affecting how they spin and collisions with other asteroids.”

To study how Bennu and other similar asteroids may change, however, he and his colleagues needed to take a peek inside.

This is where the team got lucky. When OSIRIS-REx first arrived at Bennu, the spacecraft spotted something unusual: Over and over again, tiny bits of material, some just the size of marbles, seemed to pop off the asteroid and into space. In many cases, those particles circled Bennu before falling back down to the surface. Members of the mission’s radio science team at JPL were able to witness how the body’s gravity worked first-hand—a bit like the apocryphal story of Isaac Newton inferring the existence of gravity after observing an apple falling on his head.

“It was a little like someone was on the surface of the asteroid and throwing these marbles up so they could be tracked,” Scheeres said. “Our colleagues could infer the gravity field in the trajectories those particles took.”

Squishy center

In the new study, Scheeres and his colleagues combined those records of Bennu’s gravity at work with data from OSIRIS-REx itself—precise measurements of how the asteroid tugged on the spacecraft over a period of months. They discovered something surprising: Before the mission began, many scientists had assumed that Bennu would have a homogenous interior. As Scheeres put it, “a pile of rocks is a pile of rocks.”

But the gravity field measurements suggested something different. To explain those patterns, certain chunks of Bennu’s interior would likely need to be more tightly packed together than others. And some of the least dense spots in the asteroid seemed to lie around the distinct bulge at its equator and at its very core.

“It’s as if there is a void at its center, within which you could fit a couple of football fields,” Scheeres said.

The asteroid’s spin may be responsible for that void. Scientists know that the asteroid is spinning faster and faster over time. That building momentum could, Scheeres said, be slowly pushing material away from the asteroid’s center and toward its surface. Bennu, in other words, may be in the process of spinning itself into pieces.

“If its core has a low density, it’s going to be easier to pull the entire asteroid apart,” Scheeres said.

For the scientist, the new findings are bittersweet: After measuring Bennu’s gravity field, Scheeres and his team have mostly wrapped up their work on the OSIRIS-REx mission.

Their results have contributed to the mission’s sample analysis plan—currently in development. The returned sample will be analyzed to determine the cohesion between grains—a key physical property that affects the mass distribution observed in their study.

“We were hoping to find out what happened to this asteroid over time, which can give us better insight into how all of these small asteroids are changing over millions, hundreds of millions or even billions of years,” Scheeres said. “Our findings exceeded our expectations.”

The University of Arizona leads science operations for OSIRIS-REx. NASA’s Goddard Space Flight Center in Maryland manages the overall mission.

Other coauthors on the new study include researchers at the Jet Propulsion Laboratory, Smithsonian Institution, The Open University, Northern Arizona University, KinetX Aerospace, Inc., NASA Goddard Space Flight Center, University of Maryland, Johns Hopkins University, York University, University of British Columbia, Southwest Research Institute, Université Côte d’Azur and University of Arizona.

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Where no spacecraft has gone before: A close encounter with binary asteroids

Anonymous — Thu, 10 Sep 2020 16:35:14 +0000

Where no spacecraft has gone before: A close encounter with binary asteroids Anonymous (not verified) Thu, 09/10/2020 - 10:35

CU �鶹ӰԺ and Lockheed Martin will lead a new space mission to capture the first-ever closeup look at a mysterious class of solar system objects: binary asteroids.

These bodies are pairs of asteroids that orbit around each other in space, much like the Earth and moon. In a project review on Sept. 3, NASA gave the official go-ahead to the Janus mission, named after the two-faced Roman god. The mission will study these asteroid couplets in never-before-seen detail.

Asteroids by the numbers

1996 FG3

5,380 feet: Diameter of primary asteroid
1,575 feet: Diameter of secondary asteroid
7.3 trillion pounds: Mass of both asteroids combined
64 million miles: Closest approach to Earth

1991 VH

3,412 feet: Diameter of primary asteroid
1,378 feet: Diameter of secondary asteroid
3.3 trillion pounds: Mass of both asteroids combined
90 million miles: Closest approach to Earth

It will be a moment for twos: In 2022, the Janus team will launch two identical spacecraft that will travel millions of miles to individually fly close to two pair of binary asteroids. Their observations could open up a new window into how these diverse bodies evolve and even burst apart over time, said Daniel Scheeres, the principle investigator for Janus.

“Binary asteroids are one class of objects for which we don’t have high-resolution scientific data,” said Scheeres, distinguished professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at CU �鶹ӰԺ. “Everything we have on them is based on ground observations, which don’t give you as much detail as being up close.”

The mission, which will cost less than $55 million under NASA’s SIMPLEx program, may also help to usher in a new era of space exploration, said Lockheed Martin’s Josh Wood. He explained that Janus’ twin spacecraft are designed to be small and nimble, each one about the size of a carry-on suitcase.

“We see an advantage to be able to shrink our spacecraft,” said Wood, project manager for the mission. “With technology advancements, we can now explore our solar system and address important science questions with smaller spacecraft.”

Janus is led by the �鶹ӰԺ, where Scheeres is based, which will also undertake the scientific analysis of images and data for the mission. Lockheed Martin will manage, build and operate the spacecraft.

Fly-bys

For Lockheed Martin and Scheeres, the Janus mission is the latest step in a long history of getting up close to asteroids. They’ve both played major roles, for example, in NASA’s OSIRIS-REx mission, which is currently in orbit around the asteroid Bennu. Lockheed Martin built and supports operations of the spacecraft, while Scheeres leads the mission’s radio science team.

“This partnership embodies two of the university’s greatest assets in aerospace,” said Vice Chancellor for Research and Innovation Terri Fiez. “Combining the top-notch research and student researchers in aerospace at CU �鶹ӰԺ with the capabilities of industry partners like Lockheed Martin enables us to accelerate transformational discoveries out into the market for real-world impact.”

But binary asteroids, which represent about 15% of the solar system’s asteroids, add a new level of complexity to the story of rocky debris in space.

Rendering of the orbital pattern of the binary asteroid 1999 KW4. (Credit: NASA/JPL)

“We think that binary asteroids form when you have a single asteroid that gets spun up so fast that the whole thing splits in two and goes through this crazy dance,” Scheeres said.

The mission will rendezvous with two binary pairs—named 1996 FG3 and 1991 VH—each showcasing a different kind of crazy dance. The pair called 1991 VH, for example, is the wildcard of the two with a “moon” that whips around a much bigger primary asteroid following a hard-to-predict pattern.

The team will use a suite of cameras to track these dynamics in unprecedented detail. Among other goals, Scheeres and his colleagues hope to learn more about how binary asteroids move—both around each other and through space.

“Once we see them up close, there will be a lot of questions we can answer, but these will raise new questions as well,” he said. “We think Janus will motivate additional missions to binary asteroids.”

Small and fast

The entire mission, Wood added, is being designed to be as flexible and hardy as possible.

Wood explained that over the last decade, spacecraft have become smaller as scientists have turned to pint-sized spacecraft called CubeSats and SmallSats to collect data. Such missions cut down on costs and preparation time by using more affordable off-the-shelf parts.

Janus’ twin spacecraft, however, will venture farther than any of these miniature missions to date. After blasting off in 2022, they’ll first complete an orbit around the sun, before heading back toward Earth and sling-shotting their way far into space and beyond the orbit of Mars. It’s a long way to go for machines that weigh only about 80 pounds each.

“I think it’s a great test for what is achievable from the aerospace community,” Wood said. “And the Colorado-centric development for this mission, combining the space talent of both CU �鶹ӰԺ and Lockheed Martin, is a testament to the skills available in the state.”

And, Wood added, the team is ready to get started in earnest on the mission: There’s a lot to do before the spacecraft launch in just two years.

“We see this evolution to smaller and more capable spacecraft being a key market in the future for scientific missions,” Wood said. “Now, we want to execute and show that we can do it.”

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How small particles could reshape Bennu and other asteroids

Anonymous — Wed, 09 Sep 2020 16:48:59 +0000

How small particles could reshape Bennu and other asteroids Anonymous (not verified) Wed, 09/09/2020 - 10:48

In January 2019, NASA’s OSIRIS-REx spacecraft was orbiting the asteroid Bennu when the spacecraft’s cameras caught something unexpected: Thousands of tiny bits of material, some just the size of marbles, began to bounce off the surface of the asteroid—like a game of ping-pong in space. Since then, many more such particle ejection events have been observed at Bennu’s surface.

OSIRIS-REx is an unprecedented effort to investigate what makes up asteroids like Bennu and how they move through space. But, as those leaping particles show, the mission has already delivered a few surprises.

“We’ve been studying asteroids for a long time and no one had ever seen this phenomenon before—these little particles getting shot off of the surface,” said Daniel Scheeres, distinguished professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. He leads the radio science team for OSIRIS-REx along with CU �鶹ӰԺ’s Jay McMahon.

Now, a series of new studies seeks to recreate and understand the observed particle ejection events, piecing together what happened and why. Scheeres and McMahon are focusing on one question in particular: How might the leaping particles change the long-term fate of Bennu and other asteroids like it?

In research published in the Journal of Geophysical Research: Planets, the duo and their colleagues report that such seemingly small occurrences may add up over time—perhaps even helping to give the asteroid its telltale shape, which is often compared to a spinning top.

“We want to know what that means for the bigger picture of how asteroids live their lives,” said McMahon, an assistant professor of aerospace engineering.

The University of Arizona leads science operations for OSIRIS-REx, which was built by the Colorado-based Lockheed Martin. NASA’s Goddard Space Flight Center in Maryland manages the overall mission.

Mass loss

McMahon added that the life of some asteroids can be pretty chaotic. One class of these bodies, which scientists call “active” asteroids, loses a significant amount of material on an ongoing basis.

“They’re almost a cross between a comet and an asteroid,” McMahon said. “They’re losing mass, and it’s substantial enough that we can see it from Earth.”

Top: A view of the Asteroid Bennu showing the bulge at its equator; bottom: An artist's depiction of OSIRIS-REx using its extendable arm to collect a sample of material from the surface of Bennu. (Credits: NASA/Goddard/University of Arizona)

Until recently, no one knew that the same thing could happen on a much smaller scale. But that’s precisely the case on Bennu. One hypothesis suggests that rapid shifts in temperature could be causing the surface of the asteroid to warp and crack, popping off small bits of material. Another study has contended that the ejections could be the result of small meteoroids smacking into Bennu.

Based on OSIRIS-REx’s observations, the particles ejected from Bennu can be as big as softballs and hit speeds of about 7 miles an hour. Even more surprising, McMahon said, a small number of these bits of debris seemed to do the impossible: They flew off the surface of Bennu, then orbited the asteroid for several days or longer.

“That shouldn’t happen in typical orbital mechanics,” McMahon said.

Put differently, basic orbital calculations suggest that all of these particles should do one of two things: Jump off the surface and fall right back down or escape from Bennu’s gravity and never come back.

Close misses

To find out why some aren’t playing by the rules, McMahon and his colleagues used detailed computer models to track the trajectories of more than 17,000 test particles ejected from Bennu. They discovered a small subset of those seem to get an assist from an unlikely source: the sun.

McMahon explained that as these objects leap off the asteroid, they are exposed to heat and radiation coming from the sun and from Bennu itself—just a little bit, but enough to occasionally give them a slight boost in speed. With the right push, those particles can, essentially, fail at falling.

“The particle gets really close to the surface and just misses,” McMahon said. “If it can do that a few times then it can get into a situation where it can live in orbit for quite a while.”

In another study published in the same series, a team led by Scheeres and McMahon tried to figure out if ejection events might even influence Bennu’s own orbit around the sun—the answer is probably not.

The group did discover something else unusual: When particles eventually land on Bennu’s surface, many appear to disproportionately fall near its equator where the asteroid has a distinct bulge. As a result, these events could be reshaping the asteroid over thousands or millions of years by moving mass from its north and south to its middle.

The findings are a prelude to another major event in the life of Bennu. Next month, OSIRIS-REx will get closer to the asteroid than ever before. Once there, the spacecraft will use a retractable arm to grab a sample from the surface and bring it back home.

Scheeres and colleagues expect even more unexpected findings from an already surprising asteroid.

Coauthors on the new study include researchers from the Jet Propulsion Laboratory, Planetary Science Institute, NASA Goddard Space Flight Center, Lockheed Martin, University of Arizona, The Open University and University of Tennessee.

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Taking the measure of an asteroid

Anonymous — Mon, 28 Oct 2019 19:49:42 +0000

Taking the measure of an asteroid Anonymous (not verified) Mon, 10/28/2019 - 13:49

Researchers at CU �鶹ӰԺ have gotten front-row seats to one of the closest encounters with an asteroid in history.

On Dec. 4, 2018, NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft zipped to within 4.5 miles of the asteroid Bennu. This space rock has an orbit that carries it relatively near to Earth about once every six years.

It was the first in a series of planned meet-ups between OSIRIS-REx and Bennu, and good practice for 2020. Next summer, the spacecraft will dip just above the asteroid’s surface, using its retractable arm to snag material from the top and then bring it back to Earth.

CU �鶹ӰԺ’s Daniel Scheeres leads the radio science team for OSIRISREx. The overall mission is led by the University of Arizona. He said it’s an unprecedented opportunity to get a zoomed-in look at a class of mysterious solar system residents.

“When you’re going to a new world, you have some idea of what it might look like,” said Scheeres, a Distinguished Professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. “Then you actually go there, and you can start comparing what you thought it might look like versus reality.”

In particular, his group has an eye on a simple-seeming but important number: Bennu’s mass.

Scheeres and his colleagues are using OSIRIS-REx’s navigational instruments to measure the minute pull that Bennu exerts on the spacecraft—information that then allows them to map out the gravity at its surface.

Scientists want to gather that kind of data for many reasons, said Jay McMahon, an assistant professor in aerospace engineering at CU �鶹ӰԺ.

Asteroids, for example, provide researchers with a rare window to look back at the beginnings of the solar system.

“One of the big draws for asteroids is that they’re leftovers from the formation of the solar system,” said McMahon, a co-investigator on the mission. “Bennu is a building block of the planets that didn’t end up in a planet.”

The results have already started to roll in. In March 2019, the researchers released their first estimates for the mass of Bennu: a respectable 73 billion kilograms.

They’ve also begun to get a closer look at the physics of this body—physics that would boggle most earthlings.

“Bennu spins fast enough to create a competition between the gravity that’s holding you down and the centrifugal acceleration, which is trying to throw you off,” Scheeres said.

And he isn’t stopping at Bennu, either. In June 2019, NASA picked a mission led by Scheeres, called Janus: Reconnaissance Missions to Binary Asteroids, as a finalist for its SIMPLEx small satellite program.

If the mission gets the final green light, Janus will send twin spacecraft to rendezvous with binary asteroids. Scientists have yet to observe such objects, in which two asteroids revolve around each other, up close.

“There are many theories of how binary asteroids form, but we haven’t had the proper measurements to sort through them all and see which is correct,” Scheeres said. “The Janus mission will do this and also help us better understand how primitive bodies in the solar system have formed and evolved over time.”

In other words, the solar system’s asteroids are becoming a little less puzzling thanks to CU �鶹ӰԺ.

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