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#260 by ddspaceman on 12 Sep, 2023 20:34
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NASA
@NASA
Lucy’s locked in. 🔒
The #LucyMission got its first view of Dinkinesh, the first of 10 asteroids the spacecraft will visit on its 12-year trip.
Here are images Lucy took from 14 million miles (23 million km) away. Close approach expected Nov 1, 2023:https://www.nasa.gov/feature/goddard/2023/nasa-s-lucy-spacecraft-captures-its-1st-images-of-asteroid-dinkinesh
https://twitter.com/NASA/status/1701331318485725313
Credits: NASA/Goddard/SwRI/Johns Hopkins APL
The small dot moving against the background of stars is the first view from NASA’s Lucy spacecraft of the main belt asteroid Dinkinesh, the first of 10 asteroids that the spacecraft will visit on its 12-year voyage of discovery. Lucy captured these two images on Sept. 2 and 5, 2023. On the left, the image blinks between these first two images of Dinkinesh. On the right, the asteroid is circled to aid the eye.
Lucy took these images while it was 14 million miles (23 million km) away from the asteroid, which is only about a half-mile wide (1 km). Over the next two months, Lucy will continue toward Dinkinesh until its closest approach of 265 miles (425 km) on Nov. 1, 2023. The Lucy team will use this encounter as an opportunity to test out spacecraft systems and procedures, focusing on the spacecraft’s terminal tracking system, designed to keep the asteroid within the instruments’ fields of view as the spacecraft flies by at 10,000 mph (4.5 km/s). Lucy will continue to image the asteroid over the next months as part of its optical navigation program, which uses the asteroid’s apparent position against the star background to determine the relative position of Lucy and Dinkinesh to ensure an accurate flyby. Dinkinesh will remain an unresolved point of light during the long approach and won't start to show surface detail until the day of the encounter.
The brightest star in this field of view is HD 34258, a 7.6 magnitude star in the constellation Auriga that is too dim to be seen by the naked eye from Earth. At this distance, Dinkinesh is only 19 magnitude, about 150,000 times fainter than that star. Celestial north is to the right of the frame, which is about 74,500 miles across (120,000 km). The observations were made by Lucy’s high-resolution camera, the L’LORRI instrument – short for Lucy LOng Range Reconnaissance Imager – provided by the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.
Lucy’s principal investigator, Hal Levison, is based out of the Boulder, Colorado, branch of Southwest Research Institute, headquartered in San Antonio, Texas. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the Science Mission Directorate at NASA Headquarters in Washington.
For more information about NASA’s Lucy mission, visit:
https://www.nasa.gov/lucy
Written by Katherine Kretke
Southwest Research Institute
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#261 by FutureSpaceTourist on 19 Oct, 2023 19:29
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https://science.nasa.gov/missions/lucy/nasas-lucy-spacecraft-preparing-for-its-first-asteroid-flyby/Quote
NASA’s Lucy Spacecraft Preparing for its First Asteroid Flyby
NASA Science Editorial Team
OCT 19, 2023
ARTICLE
NASA’s Lucy spacecraft is preparing for its first close-up look at an asteroid. On Nov. 1, it will fly by asteroid Dinkinesh and test its instruments in preparation for visits in the next decade to multiple Trojan asteroids that circle the Sun in the same orbit as Jupiter.QuoteOn Nov. 1, 2023, NASA's Lucy spacecraft will fly by the small Main Belt asteroid Dinkinesh (previously known as 1999 VD57). This asteroid flyby was added to Lucy’s list of targets in January of 2023.
Credits: NASA's Goddard Space Flight Center
Dinkinesh, less than half a mile, or 1 kilometer, wide, circles the Sun in the main belt of asteroids located between the orbits of Mars and Jupiter. Lucy has been visually tracking Dinkinesh since Sept. 3; it will be the first of 10 asteroids Lucy will visit on its 12-year voyage. To observe so many, Lucy will not stop or orbit the asteroids, instead it will collect data as it speeds past them in what is called a “flyby.”
“This is the first time Lucy will be getting a close look at an object that, up to this point, has only been an unresolved smudge in the best telescopes,” said Hal Levison, Lucy principal investigator from the Southwest Research Institute, which is headquartered in San Antonio. “Dinkinesh is about to be revealed to humanity for the first time.”
The primary aim of the Lucy mission, which launched Oct. 16, 2021, is to survey the Jupiter Trojan asteroids, a never-before-explored population of small bodies that orbit the Sun in two “swarms” that lead and follow Jupiter in its orbit. However, before Lucy gets to the Trojans, it will fly by another main belt asteroid in 2025 called Donaldjohanson for additional in-flight tests of the spacecraft systems and procedures.
During the Dinkinesh flyby, the team will test its terminal-tracking system that will allow the spacecraft to autonomously pinpoint the location of the asteroid, keeping it within the instruments’ field-of-view throughout the encounter.
As this encounter is intended as a test of Lucy’s systems, scientific observations will be simpler than for the mission’s main targets. The spacecraft and the platform that holds the instruments will move into position two hours before the closest approach to Dinkinesh. Once in place, the spacecraft will begin collecting data with its high-resolution camera (L’LORRI) and its thermal-infrared camera (L’TES). One hour before closest approach, the spacecraft will begin tracking the asteroid with the terminal-tracking system. Only in the last eight minutes will Lucy be able to collect data with MVIC and LEISA, the color imager and infrared spectrometer that comprise the L’Ralph instrument. Lucy’s closest approach is expected to occur at 12:54 p.m. EDT, when the spacecraft will be within 270 miles (430 kilometers) of the asteroid. Lucy will perform continuous imaging and tracking of Dinkinesh for almost another hour. After that time, the spacecraft will reorient itself to resume communications with Earth but will continue to periodically image Dinkinesh with L’LORRI for the next four days.
“We’ll know what the spacecraft should be doing at all times, but Lucy is so far away it takes about 30 minutes for radio signals to travel between the spacecraft and Earth, so we can’t command an asteroid encounter interactively,” said Mark Effertz, Lucy chief engineer at Lockheed Martin Space in Littleton, Colorado. “Instead, we pre-program all the science observations. After the science observations and flyby are complete, Lucy will reorient its high-gain antenna toward Earth, and then it will take nearly 30 minutes for the first signal to make it to Earth.”
After confirming the spacecraft's health, engineers will command Lucy to send science data of the encounter to Earth. This data downlink will take several days.
While the primary goal of the Dinkinesh encounter is an engineering test, mission scientists hope to also use the captured data to glean insights about the link between larger main belt asteroids explored by previous NASA missions and the smaller near-Earth asteroids.
After the Dinkinesh encounter, the Lucy spacecraft will continue in its orbit around the Sun, returning to the Earth’s vicinity for its second gravity assist in December 2024. This push from Earth will send it back to the main asteriod belt for its 2025 Donaldjohanson flyby, and then on to the Jupiter Trojan asteroids in 2027.
Lucy’s principal investigator is based out of the Boulder, Colorado, branch of Southwest Research Institute, headquartered in San Antonio. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the Science Mission Directorate at NASA Headquarters in Washington.
For more information about NASA’s Lucy mission, visit: https://www.nasa.gov/lucy
Katherine Kretke,
Southwest Research Institute -
#262 by vjkane on 26 Oct, 2023 15:10
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A journal paper on the L'Ralph instrument capabilities and implementation is available
L’Ralph: A Visible/Infrared Spectral Imager for the Lucy Mission to the Trojans
The paper is open access. -
#263 by FutureSpaceTourist on 01 Nov, 2023 15:36
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https://blogs.nasa.gov/lucy/2023/11/01/nasas-lucy-spacecraft-hours-away-from-1st-asteroid-encounter/Quote
NASA’s Lucy Spacecraft Hours Away from 1st Asteroid Encounter
We are only a few hours away from the NASA Lucy spacecraft’s first close up look at the small inner-main belt asteroid, Dinkinesh. Dinkinesh is 10 to 100 times smaller than the Jupiter Trojan asteroids that are the mission’s main targets. The Dinkinesh encounter serves as a first in-flight test of the spacecraft’s terminal tracking system.
Lucy’s closest approach will occur at 12:54 p.m. EDT (16:54 UTC) at a distance within 270 miles (430 km) of Dinkinesh. However, there won’t be much time to observe the asteroid at this distance as Lucy speeds past at 10,000 mph (4.5 km/s).
Two hours before closest approach, the spacecraft and the rotational platform that holds Lucy’s science instruments (the instrument pointing platform) will be commanded to move into encounter configuration. After this point, the spacecraft’s high-gain antenna will point away from the Earth and the spacecraft will not be able to return data for the remainder of the encounter.
Shortly thereafter, the high-resolution grayscale camera on Lucy, L’LORRI, will begin taking a series of images every 15 minutes. (L’LORRI, short for Lucy’s Long Range Reconnaissance Imager, is supplied by the Johns Hopkins Applied Physics Laboratory.) Dinkinesh has been visible to L’LORRI as a single point of light since early September when the team began using the instrument to assist with spacecraft navigation. The team estimates that at a distance of just under 20,000 miles (30,000 km), Dinkinesh may appear to be a few pixels in size, just barely resolved by the camera.
Additionally, Lucy’s thermal infrared instrument, L’TES, will begin collecting data. L’TES (formally the Lucy Thermal Emission Spectrometer, provided by Arizona State University) is not designed to observe an asteroid as small as Dinkinesh, so the team is interested to see if L’TES is able to detect the asteroid and measure its temperature during the encounter.
An hour before the closest approach, the spacecraft will begin actively tracking Dinkinesh using the onboard terminal tracking system. The spacecraft will use T2Cam (the Terminal Tracking Cameras, provided by Malin Space Science Systems), to repeatedly image the asteroid. In the minutes around closest approach, this system is designed to autonomously reorient the spacecraft and its instrument pointing platform as needed to keep the asteroid centered in the cameras’ field of view. Testing this system is the primary goal of this encounter.
Ten minutes before closest approach, the spacecraft is instructed to begin “closest approach imaging” with the L’LORRI instrument. In these images, taken every 15 seconds at three different exposure times, the asteroid will be several hundred pixels across, allowing the team an unprecedented view of this small main belt asteroid, which is estimated to be less than half a mile (1 km) in diameter.
Lucy will wait until about six minutes before closest approach to begin taking data with its color imager (the Multi-spectral Visible Imaging Camera, MVIC) and infrared spectrometer (Linear Etalon Imaging Spectral Array, LEISA), which together comprise the L’Ralph instrument (provided by NASA’s Goddard Space Flight Center in Greenbelt, Maryland).
About six minutes after the closest approach, L’Ralph will stop taking data, and Lucy will conclude the closest approach observations. By this time, the spacecraft will already be almost 1,700 miles (2,700 km) past the asteroid. Lucy will begin a maneuver referred to as a “pitchback” in which it reorients its solar arrays toward the Sun while the instrument pointing platform continues to autonomously track the asteroid as the spacecraft departs. This maneuver is designed to be carried out slowly to minimize spacecraft vibrations as the spacecraft moves its large solar arrays. L’LORRI will image Dinkinesh throughout this process to monitor spacecraft stability.
Once the spacecraft is over 8,000 miles (13,000 km) from the asteroid, Lucy will stop actively tracking the position of Dinkinesh. From that point on, the team expects the asteroid to remain visible to the spacecraft’s cameras without the need to reposition the spacecraft or instruments.
Two hours after closest approach, the L’TES instrument will be instructed to stop taking data. L’LORRI will continue periodically observing the asteroid for another four days to monitor the light curve of the asteroid.
Once Lucy turns its high-gain antenna back toward Earth, it will be able to resume communications, with an approximately 30-minute light-travel-time delay in each direction. The team expects to receive the first signal from the spacecraft within two hours of closest approach. After assessing the health and safety of the spacecraft, the team will command the spacecraft to begin downlinking the data taken during the encounter. It will take up to a week for all data to be returned to Earth via NASA’s Deep Space Network.
Author Erin Morton
Posted on November 1, 2023
Categories Lucy MissionTags asteroids, Dinkinesh, Lucy spacecraft, Trojan asteroids
Image caption:QuoteA graphic illustrating the expected motion of the NASA Lucy spacecraft and its instrument pointing platform (IPP) during the encounter with asteroid Dinkinesh. The spacecraft’s terminal tracking system is designed to actively monitor the location of Dinkinesh, enabling the spacecraft and IPP to move autonomously in order to observe the asteroid throughout the encounter. The yellow, blue, and grey arrows indicate the directions of the Sun, Earth, and Dinkinesh, respectively. The red arrow indicates motion of the spacecraft. An animation is available here. Credit: NASA/Goddard/SwRI
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#264 by FutureSpaceTourist on 01 Nov, 2023 19:05
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https://twitter.com/nasasolarsystem/status/1719804333804720321Quote
Hello Lucy! The spacecraft phoned home and is healthy. Now, the engineers will command Lucy to send science data from the Dinkinesh encounter to Earth. This data downlink will take several days. Thanks for following along today and stay tuned!
go.nasa.gov/3sgxWj7
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#265 by Blackstar on 02 Nov, 2023 17:35
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#266 by sdsds on 02 Nov, 2023 17:48
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The .gif from the above-referenced blog post. (Viewers may need to click on the image to see the stop-motion movie effect.)
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#267 by Blackstar on 02 Nov, 2023 19:12
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Back around 2009 I was the study director for the asteroids and comets panel of the planetary science decadal survey (I think we also had Pluto, but my brain is hazy on this at the moment and I am not going to look it up). I asked the panel chair why they kept getting missions approved. I knew that part of the answer was that small bodies missions are relatively less expensive than other planetary missions. But I had doubts about the science. What he told me was that one of the drivers was that every single asteroid that they had ever visited, including flybys, had some surprise. Every asteroid was different.
This flyby is another example of that--they didn't expect to find a binary asteroid but they did. Now that's not a huge scientific discovery, since the percentage of binaries is fairly high, but it helps make the point that there are going to be surprises.
There are other implications to this point, but I'll leave those for later. -
#268 by Zed_Noir on 02 Nov, 2023 22:51
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Is it more complicated to orbit a spacecraft or touch down with a retrieval spacecraft on an asteroid like Dinkinesh with an orbiting moonlet to make it cost prohibited for a Discovery class mission?
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#269 by Blackstar on 02 Nov, 2023 22:58
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Is it more complicated to orbit a spacecraft or touch down with a retrieval spacecraft on an asteroid like Dinkinesh with an orbiting moonlet to make it cost prohibited for a Discovery class mission?
It is definitely more complicated. Would that kick it out of Discovery class? Dunno. I think that what makes it complicated is figuring out the orbit/gravity, and that should not add cost to a spacecraft. What adds cost is hardware.
But I'm not sure that rendezvousing or landing on a binary is of greater scientific interest than doing that for a target of interest, like Psyche. -
#270 by CuddlyRocket on 03 Nov, 2023 06:01
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--they didn't expect to find a binary asteroid but they did.
Is it a binary pair? Lucy's camera was only on for 12 minutes and the smaller asteroid seems to have moved the width of the larger (0.5 miles) in that time, suggesting it was moving at 2.5 mph or 1.1 meters per second. What's the escape velocity for a 0.5 miles wide asteroid?
The alternative is that this was a near miss of two separately orbiting asteroids that Lucy was (extremely) lucky enough to be in position to record! It seems unlikely that the Lucy team didn't consider this possibility, but I'd be interested to know how they ruled it out. -
#271 by jgoldader on 03 Nov, 2023 09:04
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Is it a binary pair? Lucy's camera was only on for 12 minutes and the smaller asteroid seems to have moved the width of the larger (0.5 miles) in that time, suggesting it was moving at 2.5 mph or 1.1 meters per second. What's the escape velocity for a 0.5 miles wide asteroid?
It’s likely much of the apparent motion is due to parallax, as the aspect angle changed significantly in a short amount of time. it would be great if there’s enough data to estimate the orbit, and allow at least a rough determination of density. -
#272 by Phil Stooke on 03 Nov, 2023 22:58
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"It seems unlikely that the Lucy team didn't consider this possibility, but I'd be interested to know how they ruled it out."
so incredibly unlikely that it really rules itself out. Jgoldader is quite right about parallax - the little video clip was from the tracking camera which tracked the asteroid to keep it in the field of view of the other instruments. There is quite a range of viewing angles. I note that the shape of the little moon changes during the sequence. The cross-section is nearly equidimensional in the first view (and the high resolution image) but significantly elongated in the last frame. Looks to me as if its long axis is pointing at the main asteroid, suggesting synchronous rotation of the moon. -
#273 by Don2 on 04 Nov, 2023 21:19
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Asteroid autumn ... 2 for the price of 1 !
Wonder if you could use an asteroid pair to study gravity? G is one of the least well determined physical constants. Use laser distance measurements to measure the orbit produced by mutual gravitational attraction. Then use rockets to apply a force to each asteroid and measure the velocity change to determine mass. -
#274 by FossilDS on 07 Nov, 2023 18:28
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...What he told me was that one of the drivers was that every single asteroid that they had ever visited, including flybys, had some surprise. Every asteroid was different.
Speaking of surprises, it seems like Dinkinesh still has a few suprises in store for us. With more pictures of Dinkinesh and its moon being received by the Lucy science team, Dinkinesh's satellite turns out be a contact binary! It just goes to show how much these small bodies can still surprise us even after so many missions have been sent to them.
This flyby is another example of that--they didn't expect to find a binary asteroid but they did. Now that's not a huge scientific discovery, since the percentage of binaries is fairly high, but it helps make the point that there are going to be surprises.
[zubenelgenubi: Attach files, including images. Do not embed them in posts.]
science.nasa.gov article
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#275 by ddspaceman on 29 Nov, 2023 16:55
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Satellite Discovered by NASA’s Lucy Mission Gets Name
Erin Morton Posted on November 29, 2023
The satellite discovered during the first asteroid encounter of NASA’s Lucy mission has an official name. On Nov. 27, 2023, the International Astronomical Union approved the name “Selam” or ሰላም, which means “peace” in the Ethiopian language Amharic, for Dinkinesh’s moon.
“Dinkinesh is the Ethiopian name for the fossil nicknamed ‘Lucy,’”, says Raphael Marshall of the Observatoire de la Côte d’Azur in Nice, France, who originally identified Dinkinesh as a potential target of the Lucy mission. “It seemed appropriate to name its satellite in honor of another fossil that is sometimes called Lucy’s baby.” The fossil Selam, discovered by Zeresenay Alemseged in 2000 in Dikika, Ethiopia, belonged to a 3-year-old girl of the same species as Lucy; though the “baby” actually lived more than 100,000 years before Lucy.
The Lucy spacecraft flew by Dinkinesh and Selam on Nov 1, 2023. While observations leading up to the encounter had hinted that there was something interesting going on in this system, the team was surprised to discover that not only did Dinkinesh have a satellite, but that the satellite was a contact-binary, the first contact-binary satellite ever observed.
The team has completed downlinking encounter data from Lucy’s first asteroid encounter and is continuing to process it. The Dinkinesh encounter was added in January of this year as an in-flight test of the spacecraft’s systems and instruments, and all systems performed well. The tools and techniques refined with data from this encounter will help the team prepare for the mission’s main targets, the never-before-explored Jupiter Trojan asteroids. In addition to the images taken by Lucy’s high-resolution L’LORRI camera and its Terminal Tracking Cameras (T2Cam), Lucy’s other science instruments also collected data that will help scientists understand these puzzling asteroids.
The two components of the Goddard supplied L’Ralph instrument, the Multi-spectral Visible Imaging Camera (MVIC) and Linear Etalon Imaging Spectral Array (LEISA), both successfully observed the two asteroids from a variety of vantage points around closest approach. During the encounter, the two components scanned across the asteroids’ surfaces, enabling the team to assemble color images and spatially-resolved spectra of the objects.
“To assemble the final images, we must carefully account for the motion of the spacecraft, but Lucy’s accurate pointing information makes this possible,” said Amy Simon of NASA’s Goddard Space Flight Center, Greenbelt, Maryland. “These images will help scientists understand the composition of the asteroids, allowing the team to compare the makeup of the Dinkinesh and Selam and to understand how these bodies may be compositionally linked to other asteroids.”
The Arizona State University-supplied Lucy Thermal Emissions Spectrometer (L’TES) also detected the asteroids, even though, unlike the future Trojan asteroid targets, they filled only a small fraction of the instrument’s wide field of view. Scientists expect that the data will mostly provide insight into the surface properties of the larger asteroid, Dinkinesh.
“L’TES was able to detect and measure the temperature of the system for about nine minutes as the spacecraft flew by at its closest approach,” said Phil Christensen of Arizona State University, Tempe. “Different sized particles, such as sand, pebbles, and boulders, heat up differently as the asteroid rotates. The L’TES temperature measurements will allow us to study the size and physical properties of the materials on the asteroid’s surface.”
Lucy is expected to visit 9 more asteroids over the next decade in 6 separate encounters. After an Earth gravity assist in Dec. 2024, the spacecraft will return to the main asteroid belt where it will encounter asteroid Donaldjohanson in April 2025. Lucy will pass through the main belt and reach the mission’s primary targets, the Jupiter Trojan asteroids, in 2027.
By Katherine Kretke, Southwest Research Institute
https://blogs.nasa.gov/lucy/2023/11/29/satellite-discovered-by-nasas-lucy-mission-gets-name/
A false-color image of the asteroid Dinkinesh and its satellite, Selam, created using data collected by the NASA Lucy spacecraft’s color imager, the Multi-spectral Visible Imaging Camera, MVIC, on the L’Ralph instrument. This MVIC image was obtained about 100 seconds before closest approach on Nov. 1, 2023. The orange, green and violet MVIC filters were mapped to the red, green, and blue channels to create this image. Image Credit: NASA/Goddard/SwRI
A pair of stereoscopic images of the asteroid Dinkinesh and its satellite, Selam, created using data collected by the L’LORRI camera on the NASA Lucy spacecraft in the minutes around closest approach on Nov. 1, 2023. To use this image pair to get a better sense of the 3D structure of the asteroids, either relax the axes of your eyes, as if staring through the screen to infinity (so that you are looking at the left image with your left eye and the right image with your right eye), or use a stereoscope. These images have been processed to enhance contrast, and the apparent distance between Selam and Dinkinesh has been artificially reduced to facilitate simultaneous stereo view of the two objects. Credit: NASA/Goddard/SwRI/Johns Hopkins APL/NOIRLab for the original images/Brian May/Claudia Manzoni for stereo processing of the images.
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#276 by Blackstar on 01 Feb, 2024 16:38
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There was a presentation at SBAG today on the Lucy mission. Most of the presentation was science data from the recent flyby, and that data is embargoed, so they don't want anybody reporting on it. I didn't screenshot any of that, although they have developed a preliminary shape model of the asteroid they flew past.
Here are some slides.
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#277 by zubenelgenubi on 01 Feb, 2024 19:37
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There was a presentation at SBAG today on the Lucy mission. Most of the presentation was science data from the recent flyby, and that data is embargoed, so they don't want anybody reporting on it.
When is the "un-embargo-ing?" An upcoming Nature issue, or the like? -
#278 by Blackstar on 01 Feb, 2024 21:43
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There was a presentation at SBAG today on the Lucy mission. Most of the presentation was science data from the recent flyby, and that data is embargoed, so they don't want anybody reporting on it.
When is the "un-embargo-ing?" An upcoming Nature issue, or the like?
I think he mentioned LPSC, which is in March. The data he showed was not anything that would knock your socks off, and he was only showing the high level conclusions, not raw data. -
#279 by Phil Stooke on 01 Feb, 2024 23:02
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The LPSC abstracts will be available in just a few days and will certainly contain some good things.