Post by: redliox on 11/01/2018 12:15 am
It's just passed the Key Decision Point C Review. The Lucy team will officially begin spacecraft and instrument design before moving into Critical Design Review, after which Lucy will actually get built. The mission itself will launch in 3 years in the October of 2021.
The official mission webpage: http://lucy.swri.edu/ (http://lucy.swri.edu/)
NASA's Lucy webpage: https://www.nasa.gov/content/goddard/lucy-the-first-mission-to-jupiter-s-trojans (https://www.nasa.gov/content/goddard/lucy-the-first-mission-to-jupiter-s-trojans)
Lucy launch thread (https://forum.nasaspaceflight.com/index.php?topic=47331.0), October 16, 2021
Post by: jeffkruse on 06/11/2019 07:45 pm
Post by: theinternetftw on 10/22/2019 04:57 am
https://www.nasa.gov/feature/goddard/2019/lucy-mission-clears-critical-milestone
Post by: catdlr on 10/22/2019 06:05 am
NASA Goddard
Oct 21, 2019
Beyond the asteroid belt are "fossils of planet formation" known as the Trojan asteroids. These primitive bodies share Jupiter's orbit in two vast swarms, and may hold clues to the formation and evolution of our solar system. Now, NASA is preparing to explore the Trojan asteroids for the first time. A mission called Lucy will launch in 2021 and visit seven asteroids over the course of twelve years - one in the main belt and six in Jupiter's Trojan swarms.
Lucy is named for the famous hominid fossil that shed light on our early human ancestors; by making the first exploration of the Trojan asteroids, the Lucy mission will improve our understanding of the early solar system, and be the first to uncover these fossils of planet formation.
Learn more about the Lucy mission: https://www.nasa.gov/lucy
Universal Production Music: Canyon of Dreams
This video is public domain and along with other supporting visualizations can be downloaded from the Scientific Visualization Studio at: http://svs.gsfc.nasa.gov/13352
Credit: NASA's Goddard Space Flight Center/Dan Gallagher
https://youtu.be/4ZHCwSaBzd8
Post by: jbenton on 02/01/2020 01:01 am
https://www.nasa.gov/feature/nasa-s-lucy-mission-confirms-discovery-of-eurybates-satellite (https://www.nasa.gov/feature/nasa-s-lucy-mission-confirms-discovery-of-eurybates-satellite)
Quote
Jan. 9, 2020
NASA’s Lucy Mission Confirms Discovery of Eurybates Satellite
NASA’s Lucy mission team is seeing double after discovering that Eurybates, the asteroid the spacecraft has targeted for flyby in 2027, has a small satellite. This “bonus” science exploration opportunity for the project was discovered using images taken by the Hubble Space Telescope’s Wide Field Camera 3 in September 2018, December 2019, and January 2020.
...
“This newly discovered satellite is more than 6,000 times fainter than Eurybates, implying a diameter less than 1 km,” said Southwest Research Institute’s Hal Levison, principal investigator of the mission. “If this estimate proves to be correct, it will be among the smallest asteroids visited.”Eurybates was first observed with Hubble in a search for small satellites in 2018, but it wasn’t until this past November when a Lucy team member noticed something in the data indicating a possible satellite.
“We asked for more Hubble time to confirm, and they gave us three tries,” said Keith Noll, Lucy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-discoverer of the satellite.
The team was quick to make the first set of confirmation observations in December and early January. The possible satellite was hard to see and moving on an unknown orbit around the much brighter Eurybates. There was no guarantee that it would be visible in the new images. “In the first two observations in December we didn’t see anything, so we began to think we might be unlucky. But on the third orbit, there it was,” said Noll.
The team is working with Hubble schedulers to decide when to make the next observations after Eurybates becomes observable again. Due to the orbits of Earth and Eurybates, and because Hubble cannot be pointed toward the Sun, further observations are not possible until June. In the meantime, the team is using current observation data to study the satellite’s orbit around the asteroid, which will help scientists determine the best times for observations.
While there is no impact to the spacecraft architecture or schedule, the project team is carefully planning how to safely examine the new satellite while ensuring the mission’s requirement to study Eurybates is fully met.
...
“There are only a handful of known Trojan asteroids with satellites, and the presence of a satellite is particularly interesting for Eurybates,” said Thomas Statler, Lucy Program Scientist at NASA Headquarters in Washington. “It’s the largest member of the only confirmed Trojan collisional family – roughly 100 asteroids all traceable to, and probably fragments from, the same collision.”
The opportunity to study a prospective collisional satellite at close range will help our fundamental understanding of collisions, which Statler says may be responsible for the formation of satellites in other small body populations.
...
Post by: Citabria on 02/18/2020 03:47 pm
http://lucy.swri.edu//mission/Tour.html (http://lucy.swri.edu//mission/Tour.html)
Post by: zubenelgenubi on 02/29/2020 12:19 am
Post by: redliox on 09/01/2020 11:12 pm
Quote
Aug. 28, 2020
NASA’s Lucy Mission One Step Closer to Exploring the Trojan Asteroids
NASA’s first mission to explore the Trojan asteroids is one step closer to launch. The Discovery Program’s Lucy mission passed a critical milestone and is officially authorized to transition to its next phase.
This major decision was made after a series of independent reviews of the status of the spacecraft, instruments, schedule and budget. The milestone, known as Key Decision Point-D (KDP-D), represents the official transition from the mission’s development stage to delivery of components, testing, assembly and integration leading to launch. During this part of the mission’s life cycle, known as Phase D, the spacecraft bus (the structure that will carry the science instruments) is completed, the instruments are integrated into the spacecraft and tested, and the spacecraft is shipped to NASA's Kennedy Space Center in Florida for integration with the launch vehicle.
“Each phase of the mission is more exciting than the last,” says Lucy Principal Investigator Hal Levison of Southwest Research Institute in Boulder, CO. “While, of course, Lucy still has several years and a few billion miles to go before we reach our real goal – exploring the never-before-seen Trojan asteroids – seeing this spacecraft come together is just incredible.”
...
The oxidizer tank has already been integrated with the spacecraft, and the instrument integration starts in October. All spacecraft assembly and testing will be completed by the end of July 2021, when the spacecraft will be shipped to Kennedy Space Center in Cape Canaveral, Florida in preparation for the launch window opening on October 16, 2021. After launch, Lucy will have a long cruise phase before it arrives at its first target. Lucy is flying out to the distance of Jupiter to make close fly-bys past a record-breaking number of asteroids, encountering the first of eight targets in April 2025 and the final binary pair of asteroids in March 2033.
The next major milestone is the Mission Operation Review, scheduled in October 2020, which assesses the project's operational readiness and its progress towards launch.
Southwest Research Institute in Boulder, Colorado, is the principal investigator institution for Lucy. NASA Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin Space near Denver is building the spacecraft and will perform spacecraft flight operations. Instruments will be provided by Goddard, the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, and Arizona State University.
Post by: jbenton on 09/14/2020 10:00 pm
Post by: jacqmans on 11/10/2020 12:53 pm
Before the NASA Lucy mission can begin its long journey to the Trojan asteroids, the first scientific camera to be delivered to the spacecraft had to take a 1,500 mile journey across the continental United States.
The Lucy LOng Range Reconnaissance Imager (L’LORRI) traveled from the Johns Hopkins Applied Physics Laboratory (APL), in Laurel, Maryland, where it was built and tested, to Lockheed Martin Space, in Littleton, Colorado, where the spacecraft is being assembled. It was received safely at Lockheed Martin on October 25 and was successfully integrated onto the spacecraft on October 30.
“Lucy is an amazing spacecraft, but I’m always looking forward to the day when we start getting data from these never before seen fossils of the solar system,” says Lucy principal investigator, Hal Levison. “Now that we have installed the first scientific instrument, we are one step closer to that day. I would like to thank the APL team for all their hard work getting the instrument to the spacecraft on time during the COVID19 pandemic.”
The Trojan asteroids are two groups of asteroids that lead and trail Jupiter in its orbit around the Sun. Scientists have evidence that these asteroids may have been scattered from all over the outer solar system early in the solar system’s history, and have been trapped in these stable locations for over four billion years. No spacecraft has ever been to this population of small bodies, and Lucy will fly by seven of these Trojan asteroids, plus a main belt asteroid, allowing it to survey the diversity of this population in a single record-breaking mission.
L’LORRI is the first scientific instrument to be installed on Lucy. L’LORRI is sometimes referred to as Lucy’s “eagle eyes” because it has the highest spatial resolution of all of Lucy’s cameras. This instrument, which is panchromatic (covering 0.35 to 0.85 microns), will produce black and white images that will provide the most detailed views of the surfaces of these never before seen bodies.
“L’LORRI is quite similar to its predecessor, the LORRI instrument that flew on New Horizons and sent back incredible images of the Pluto system and the Kuiper belt object Arrokoth,” says Hal Weaver, lead of the instrument team at APL. “I can’t wait to see the images from this L’LORRI instrument and what they will teach us about the Trojan asteroids.”
In addition to L’LORRI, two more scientific instruments will be added to Lucy over the next few months. L’TES (the Lucy Thermal Emission Spectrometer), is being built at Arizona State University in Tempe, Arizona. L’Ralph, which is being built at NASA’s Goddard Space Flight Center in Greenbelt Maryland, is two instruments in one, a color visible imager (the Multi-spectral Visible Imaging Camera, MVIC) and an infrared imaging spectrometer (Linear Etalon Imaging Spectral Array, LEISA). Together, along with the Terminal Tracking cameras T2CAM and the High Gain Antenna, which will facilitate both communications and radio science, these instruments will reveal this never before explored population of asteroids in unprecedented detail.
“The L’LORRI Pre-Environmental Review was held back in early August and to see what this team has accomplished over the last several months, under a pandemic, is astonishing,” said Donya Douglas-Bradshaw, Lucy project manager from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “I commend the L’LORRI team for their hard work, resiliency, and dedication. I'm looking forward to the first time we power up L’LORRI on the spacecraft.”
Southwest Research Institute’s Hal Levison and Cathy Olkin are the principal investigator and deputy principal investigator of the Lucy Mission. NASA’s Goddard Space Flight Center provides overall mission management, systems engineering and safety and mission assurance. Lockheed Martin Space is building 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 agency’s Science Mission Directorate in Washington, D.C.
https://www.nasa.gov/feature/goddard/2020/first-scientific-instrument-installed-on-lucy-spacecraft
Post by: redliox on 11/25/2020 08:06 pm
https://twitter.com/i/status/1331618126614704129 (https://twitter.com/i/status/1331618126614704129)
Post by: catdlr on 11/26/2020 01:59 am
Lucy's Journey: Episode 1
https://youtu.be/NlHJV2OyxII
Post by: whitelancer64 on 11/26/2020 02:15 am
Post by: vjkane on 11/26/2020 03:03 pm
Is there any chance that, on a mission extension, Lucy might fly by 624 Hektor?I don't know about it flying by 624 Hektor, but in the press conference announcing the selection of Lucy and Psyche, the Lucy PI said that the team had looked at extended mission options, and one included a flyby of the Psyche asteroid (now, obviously no longer needed).
Lucy could be the mission that just keeps giving. I presume that the limiting factor is fuel for the targeted flybys; there could be a number of flybys past the prime mission.
Post by: redliox on 11/26/2020 10:12 pm
Is there any chance that, on a mission extension, Lucy might fly by 624 Hektor?I don't know about it flying by 624 Hektor, but in the press conference announcing the selection of Lucy and Psyche, the Lucy PI said that the team had looked at extended mission options, and one included a flyby of the Psyche asteroid (now, obviously no longer needed).
Lucy could be the mission that just keeps giving. I presume that the limiting factor is fuel for the targeted flybys; there could be a number of flybys past the prime mission.
I'd love to see a Hektor flyby, in part because it was the first binary/contact asteroid discovered and how it remains the largest known Trojan. I keep forgetting which Trojan cloud it's part of although I think the "Greek camp."
Post by: Phil Stooke on 11/26/2020 11:04 pm
Post by: FutureSpaceTourist on 12/03/2020 07:04 pm
Post by: FutureSpaceTourist on 04/21/2021 08:50 am
Post by: jbenton on 04/22/2021 12:33 am
That is correct. 624 Hektor, however is in the "Greek camp", for whatever reason. The only other one to be in the wrong camp is 617 Patroclus which is in the "Trojan camp". The fact that those are the only two seems kind of fitting to me.Hektor was the Prince of Troy, killed by the Greek Achilles.Is there any chance that, on a mission extension, Lucy might fly by 624 Hektor?I don't know about it flying by 624 Hektor, but in the press conference announcing the selection of Lucy and Psyche, the Lucy PI said that the team had looked at extended mission options, and one included a flyby of the Psyche asteroid (now, obviously no longer needed).
Lucy could be the mission that just keeps giving. I presume that the limiting factor is fuel for the targeted flybys; there could be a number of flybys past the prime mission.
I'd love to see a Hektor flyby, in part because it was the first binary/contact asteroid discovered and how it remains the largest known Trojan. I keep forgetting which Trojan cloud it's part of although I think the "Greek camp."
Post by: Phil Stooke on 04/22/2021 10:33 pm
Post by: AegeanBlue on 04/23/2021 08:57 pm
Achilles was the first 'trojan' discovered, then Hektor, both at L4. Then Patroclus was discovered at L5. Only after that did the idea come about of putting Greek names in L4 and Trojan names in L5, so the later names conform to that idea, but that left Hektor and Patroclus in the wrong places. They are regarded as spies in the camps of their enemies.
The only major Homeric heroes who go spying in the enemy camp are Odysseus and Diomedes in the Illiad Rhapsody K, nowadays usually called book 10 in English. Think of Patroclus attacking the Trojan Camp as he does in Rhapsody Π (book 14) and Hector attacking the Greek camp as he does in Rhapsody Θ (book 8 )
Post by: Alpha_Centauri on 04/23/2021 10:14 pm
Post by: Sesquipedalian on 04/24/2021 02:32 am
Astronomers should never be allowed to name anything, exhibit #2497562
7470 Jabberwock would like to disagree with you.
Post by: Phil Stooke on 04/24/2021 02:42 am
Post by: Rondaz on 09/16/2021 03:06 pm
Linda Herridge Posted on August 11, 2021
NASA’s Lucy spacecraft is now in Florida – its final Earth-bound destination – before embarking on a mission to study the Jupiter Trojan asteroids. A United States Air Force C-17 cargo plane from Charleston Air Force Base in South Carolina, flew to Buckley Space Force Base in Aurora, Colorado, to pick up the spacecraft. The aircraft, with Lucy safely inside, then touched down at the Launch and Landing Facility runway at NASA’s Kennedy Space Center on July 30, 2021. From there, the spacecraft was transported to an Astrotech Space Operations processing facility in nearby Titusville to undergo final preparations before liftoff.
Named after a fossilized human ancestor whose skeleton provided discoverers insight into humanity’s evolution, the Lucy mission will do much of the same, providing scientists and researchers a look into the origins of our solar system.
The Trojan asteroids orbit the Sun in two groups: one group lies ahead of Jupiter while the other trails behind. Stabilized by both the Sun and Jupiter, those swarms of asteroids are thought to be remnants of the initial material that formed the planets within the solar system. Throughout the duration of the mission, Lucy will visit eight different asteroids over the span of 12 years, unlocking new information about the primitive bodies that created our early solar system.
Lucy is scheduled to launch on a United Launch Alliance Atlas V rocket from Cape Canaveral Space Force Station on Oct. 16. The launch is being managed by the NASA’s Launch Services Program based at Kennedy, America’s multi-user spaceport. The mission will be the first to study the Trojans.
https://blogs.nasa.gov/lucy/2021/08/11/nasas-lucy-spacecraft-readies-for-launch-at-kennedy/
Post by: Rondaz on 09/16/2021 03:06 pm
James Cawley Posted on September 16, 2021
Launch preparations for NASA’s Lucy spacecraft are well underway at an Astrotech Space Operations processing facility in Titusville, Florida. The spacecraft arrived at the agency’s Kennedy Space Center on July 30, 2021, and shortly after its arrival, was transported to Astrotech’s facility nearby to undergo prelaunch processing.
The latest milestone occurred on Sept. 9, when Lucy was attached to the payload adapter. This is the physical structure that will secure the spacecraft to the launch vehicle – in this case, a United Launch Alliance Atlas V rocket. Closer to launch, the payload adapter will be attached to the rocket’s second stage.
Liftoff of the Atlas V is scheduled for Oct. 16 from Cape Canaveral Space Force Station, and the launch is being managed by NASA’s Launch Services Program based at Kennedy – America’s multi-user spaceport.
Lucy will be the first space mission to study the Jupiter Trojan asteroids. These asteroids are thought to be remnants of the initial material that formed the planets within the solar system. Over the course of 12 years, Lucy will visit eight different asteroids, providing researchers and scientists with a never-before-seen glimpse into the origins of our solar system.
https://blogs.nasa.gov/lucy/2021/09/16/nasas-lucy-spacecraft-prepares-for-journey-to-jupiter/
Post by: centaurinasa on 10/05/2021 03:45 pm
https://twitter.com/NASAKennedy/status/1445383093712474116
Post by: illectro on 10/06/2021 09:30 pm
A press release from Aerojet-Rocketdyne tells us about the small monoprop thrusters used for attitude contol
https://www.rocket.com/media/news-features/aerojet-rocketdyne-propel-lucy-first-ever-mission-study-trojan-asteroids
"eight MR-103J thrusters and six MR-106L thrusters"
Another product page shows that the main engine is the Leros 1C which uses Hydrazine with MON as an oxidizer
https://www.nammo.com/wp-content/uploads/2021/03/2021-Nammo-Westcott-Liquid-Engine-LEROS1C.pdf
Post by: Targeteer on 10/06/2021 11:14 pm
MEDIA ADVISORY M21-126
NASA Sets Coverage, Invites Public to Virtually Join Lucy Launch
Artist’s illustration of the Lucy concept.
Artist’s illustration of the Lucy concept.
Credits: Southwest Research Institute
NASA will provide coverage of upcoming prelaunch and launch activities for Lucy, the agency’s first mission to explore the Jupiter Trojan asteroids.
Lucy is scheduled to launch no earlier than 5:34 a.m. EDT Saturday, Oct. 16, on a United Launch Alliance (ULA) Atlas V 401 rocket from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida.
Live launch coverage will begin at 5 a.m. EDT on NASA Television, the NASA app, and the agency’s website. NASA will hold a prelaunch briefing Wednesday, Oct. 13, and science and engineering briefings Oct. 14.
Over its 12-year primary mission, Lucy will explore a record-breaking number of asteroids. The spacecraft will fly by one asteroid in the solar system’s main belt and seven Trojan asteroids. Lucy’s path will circle back to Earth three times for gravity assists, which will make it the first spacecraft ever to return to our planet’s vicinity from the outer solar system.
Due to the coronavirus (COVID-19) pandemic, all media participation in news conferences will be remote dial-in only. A phone bridge will be provided for each briefing.
Full mission coverage is as follows. Information is subject to change:
Wednesday, Oct. 13
1 p.m.: Lucy prelaunch news conference with the following participants:
Thomas Zurbuchen, associate administrator, NASA’s Science Mission Directorate at the agency’s Headquarters in Washington.
Hal Levison, Lucy principal investigator, Southwest Research Institute.
Donya Douglas-Bradshaw, Lucy Project Manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
John Elbon, Chief Operating Officer, United Launch Alliance.
Launch weather officer, 45th Weather Squadron, Space Launch Delta 45, Cape Canaveral Space Force Station.
Omar Baez, Lucy Launch Director, NASA’s Launch Services Program at Kennedy Space Center in Florida.
For the dial-in number and passcode, please contact the Kennedy newsroom at: [email protected] no later than noon, Wednesday, Oct. 13. Members of the public may also ask questions online by using #LucyMission on social media.
Thursday, Oct. 14
10 a.m.: NASA EDGE: Live Lucy Rollout Show.
1 p.m.: Lucy science briefing with the following participants:
Adriana Ocampo, Lucy program executive, NASA Headquarters.
Cathy Olkin, Lucy deputy principal investigator, Southwest Research Institute.
Keith Noll, Lucy project scientist, Goddard.
Hal Weaver, principal investigator for Lucy’s L'LORRI instrument, Johns Hopkins Applied Physics Laboratory.
Phil Christensen, principal investigator for Lucy’s L'TES instrument, Arizona State University.
Dennis Reuter, principal investigator for Lucy’s L’Ralph instrument, Goddard.
3 p.m.: Lucy engineering briefing with the following participants:
Joan Salute, associate director for flight programs, Planetary Science Division, NASA Headquarters.
Jessica Lounsbury, Lucy project systems engineer, Goddard.
Katie Oakman, Lucy structures and mechanisms lead, Lockheed Martin Space.
Coralie Adam, deputy navigation team chief, KinetX Aerospace.
For the dial-in number and passcode, please contact the Kennedy newsroom at: [email protected] by Thursday, Oct. 14 no later than noon for the Science Briefing and 2 p.m. for the Engineering Briefing. Members of the public may also ask questions, which may be answered in real-time during the segment, by using #LucyMission on social media.
Friday, Oct. 15
3:30 p.m.: NASA Science Live with the following participants:
Carly Howett, assistant director of the Department of Space Studies, Southwest Research Institute.
Wil Santiago, deep space exploration engineer, Lockheed Martin Space.
Donya Douglas-Bradshaw, Lucy project manager, Goddard.
Brittine Young, mentor for the NASA Lucy L’SPACE academy.
Wilbert Ruperto, ambassador for the NASA Lucy L’SPACE academy.
This episode will air live on NASA Television and stream live on the agency’s Facebook, Twitter and YouTube channels. Members of the public can participate live by sending questions using #askNASA or posting a comment in the live video chat stream.
NASA TV Launch Coverage
NASA TV live coverage will begin at 5 a.m. Saturday, Oct. 16. For NASA TV downlink information, schedules, and links to streaming video, visit:
https://www.nasa.gov/live
Audio only of the news conferences and launch coverage will be carried on the NASA “V” circuits, which may be accessed by dialing 321-867-1220, -1240, -1260 or -7135. On launch day, "mission audio," countdown activities without NASA TV launch commentary, will be carried on 321-867-7135.
On launch day, a “clean feed” of the launch without NASA TV commentary will be carried on the NASA TV media channel.
NASA Website Launch Coverage
Launch day coverage will be available on the agency’s website. Coverage will include livestreaming and blog updates beginning no earlier than 5 a.m. Oct. 16, as the countdown milestones occur. On-demand streaming video and photos of the launch will be available shortly after liftoff. For questions about countdown coverage, contact the Kennedy newsroom at: 321-867-2468. Follow countdown coverage on our launch blog at:
https://www.blogs.nasa.gov/lucy
Interview Requests
Members of the media looking for interviews on the Lucy launch should submit media requests to Alana Johnson and Nancy Neal-Jones.
Public Participation
Members of the public can register to attend the launch virtually. NASA’s virtual guest program for Lucy includes curated launch resources, a behind-the-scenes look at the mission, and the opportunity for a virtual guest launch passport stamp .
Virtual NASA Social
As NASA finalizes launch preparations, the agency invites the public to join its virtual NASA Social for the #LucyMission on Facebook. Stay up to date on the latest mission activities, interact with NASA team members in real-time, and watch the launch.
Watch and Engage on Social Media
Stay connected with the mission on social media, and let people know you're following it on Twitter, Facebook, and Instagram using the hashtag #LucyMission – and tag the following accounts:
Twitter: @NASA, @NASASolarSystem, @NASASocial, @NASA_LSP, @SLDelta45
Facebook: NASA, NASASolarSystem, NASA LSP, SLDelta45
Instagram: NASA
The launch of this mission is managed by NASA’s Launch Services Program, based at Kennedy, America’s premiere multi-user spaceport. Goddard provides overall mission management, systems engineering, and safety and mission assurance. Lucy’s principal investigator is based out of the Boulder, Colorado, branch of Southwest Research Institute. 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 agency’s Science Mission Directorate in Washington.
United Launch Alliance is the rocket provider for Lucy’s launch. Lockheed Martin Space in Littleton, Colorado, built the spacecraft.
Para obtener información sobre cobertura en español en el Centro Espacial Kennedy o si desea solicitar entrevistas en español, comuníquese con Antonia Jaramillo 321-501-8425.
-end-
Post by: redliox on 10/15/2021 01:15 pm
Post by: Blackstar on 10/16/2021 12:44 pm
https://spacenews.com/atlas-5-launches-nasas-lucy-asteroid-mission/
Post by: Blackstar on 10/16/2021 12:59 pm
https://www.nap.edu/catalog/25868/report-series-committee-on-astrobiology-and-planetary-science-options-for
TROJAN TOUR AND RENDEZVOUS
Knowledge of the Trojan asteroids has increased considerably since the completion of V&V, in terms of the quality and completeness of their astronomical characterization; new kinds of telescopic observations, including in the thermal-infrared and mid-ultraviolet; and the discoveries of additional binary systems, for which we can determine masses and bulk densities, and dynamical families indicative of disruptions. We have a more complete view of their great diversity in size, shape, and composition.32 Additionally, significant advancements in understanding solar system dynamics have provided powerful constraints on the migration of Jupiter and other giant planets after their formation, and the possible origin of the Trojan swarm. Indeed, one of the key motivations for a Trojan Tour in V&V was its unique ability to resolve some of the primary debates concerning early planet formation, with great relevance to debates concerning the formation of Earth and other planets.
The traditional theory was that Trojans are remnants of Jupiter’s feedstock planetesimals, a collection of primitive bodies that were trapped in the co-orbital gravitational potential wells (Sun-Jupiter Lagrange points L4 and L5) that lead and trail Jupiter by 60 degrees in its orbit around the Sun. Modern ideas of giant planet migration make the survival of such an original swarm unlikely and have led to a new paradigm: Trojans are proto–KBOs that were scattered inward during giant planet migration, with a fraction of them being captured by Jupiter to become the L4 and L5 swarms. If true, this paradigm places important quantitative constraints on planet formation and migration,33 with predictions for the growth of terrestrial planets and the delivery of volatiles to Earth.
While modern dynamical models make a strong case for captured Trojans, there are substantial, unexplained differences between current spectroscopic properties (and thus, taxonomies) of Trojans and those of KBOs. They look like different populations. One idea is that KBOs, once trapped in Jupiter’s orbit at 5 AU, evolved thermally, chemically, and dynamically (e.g., through collisions) in ways that led to the diversity of the modern population. This idea connects deeply with our understanding of primitive asteroids in general, and with the still poorly understood connections between asteroids and comets, and the compositions of bodies that were accreted by the terrestrial planets, including Earth. As noted in V&V,34 “In-depth study of these objects will provide the opportunity to understand the degree of mixing in the solar system and to determine the composition and physical characteristics of bodies that are among the most primitive in the solar system.”
In sum, the scientific understanding of the Trojan asteroids has advanced considerably since V&V due to Earth-based observations and theoretical modeling efforts. Nevertheless, the major scientific questions posed in V&V regarding these bodies remain unanswered and, if anything, have been accentuated and made more relevant to planetary science. To address these questions requires in-depth investigation of one or more of these worlds, and these questions form the scientific basis for the selection of the Lucy multiple-Trojan-flyby Discovery mission, scheduled for launch in 2021. This mission, discussed further in Chapter 3, is the major programmatic development since V&V regarding the Trojan asteroids. Lucy takes advantage of the significant technological advancement in space solar power systems, which enables operations at Jupiter’s distance from the Sun.35 It also leverages technological advancement in instrument design. As described below, a key scientific difference between Lucy and the Trojan Tour and Rendezvous New Frontiers mission envisioned in V&V is the lack of a final rendezvous encounter and the associated instrumentation that would measure elemental composition of near-surface materials.
Post by: Blackstar on 10/16/2021 01:01 pm
TROJAN TOUR AND RENDEZVOUS
As noted above, NASA has selected for flight through its Discovery program the Lucy multiple-Trojan-asteroid flyby mission. Lucy takes advantage of significant advancement in the application of solar-power for deep-space missions. Moreover, the Lucy team also discovered a unique and powerful mission design that allows the spacecraft to tour the leading L4 Trojan cloud starting in 2027 and then fall back through the inner solar system to undergo an Earth flyby, thus enabling it to reach the trailing L5 Trojan cloud in 2033. There, it will fly by the giant binary asteroid Patroclus-Menoetius. Lucy will encounter one main belt asteroid and seven Trojan asteroids in its nominal tour (including a satellite of one Trojan and the Patroclus-Menoetius binary as two). All of the major taxonomic types among the Trojan asteroids (and outer asteroid belt asteroids in general)—so-called C, P, and D types—will be encountered. Lucy will carry visible, near-infrared, and thermal-infrared imagers and spectrometers, as well as radio science (using the high-gain antenna and associated telecommunications systems to determine the masses of the target asteroids by Doppler tracking).
V&V recommended a New Frontiers class mission that would encounter at least two Trojan asteroids and rendezvous with one for an extended exploration. Possible instrumentation could include visible and near-infrared spectrometers to measure spectral reflectance and infer composition; gamma-ray and neutron spectroscopy to elucidate elemental composition; multispectral imaging; an ultraviolet spectrometer to search for outgassing; a thermal mapper; and possibly a lidar system. Information on the interior structure of the rendezvous Trojan would be obtained from shape determination and radiometric tracking.
Finding: Creative approaches in implementation that differ from the specific mission implementation studies in V&V warrant consideration by NASA on the basis of merit in achieving science objectives. This includes accomplishing New Frontiers-level mission objectives in Discovery.
The Lucy mission aims to accomplish the preponderance of the objectives of the Trojan Tour and Rendezvous mission theme. The science objective of the Trojan Tour and Rendezvous, as described in the NF4 AO, was to “visit, observe, and characterize multiple Trojan asteroids.” While Lucy will meet this science objective, determination of elemental abundances in surface materials will not be accomplished. This relates to a major scientific rationale for the Trojan Tour and Rendezvous mission, to use composition to discriminate between planet formation hypotheses: either Trojans were captured during a solar-system-wide cataclysm during giant planet migration3 or they are leftovers of Jupiter’s local formation-swarm. Recent advances concerning the formation of Jupiter and its effect on planetesimal populations make this discrimination less clear.4,5 Results from the Lucy mission should nevertheless shed great light on planet formation models.
With current technology, elemental abundances of surface materials can be determined by gamma-ray and neutron spectroscopy, which require station-keeping with a Trojan asteroid for a considerable length of time to build up the necessary signal to noise. Complete high-resolution imaging of the rendezvous targets will also not be possible, and precise mass determination from radio tracking is more difficult from a single flyby. Lucy’s advantage, through clever tour design, is that a large number of Trojan asteroids of diverse spectral types will be visited, and on a Discovery budget. A future New Frontiers–class mission to the Trojan asteroids could potentially take advantage of technology development, such as advanced solar-electric propulsion, which could permit extended rendezvous at multiple targets, in the manner of the Dawn mission to Vesta and Ceres. However, selecting a Trojan tour mission in NF5 would not be in keeping with the optimum program balance among mission targets and types recommended strongly in V&V. Further exploration of the Trojan asteroids is justifiable on scientific grounds, but the next steps, beyond Lucy, would be best left for determination by the forthcoming decadal survey.
Finding: There is substantial, although not complete, scientific overlap between the objectives of the Lucy mission and the Trojan Tour and Rendezvous mission as outlined in V&V. Thus, reconsideration of including a Trojan Tour mission in the NF5 call by NASA is warranted, and removing a Trojan Tour mission from the list of potential targets would be appropriate. The next steps for Trojan asteroid exploration are best evaluated and prioritized by the upcoming planetary science and astrobiology decadal survey.
Post by: dsmillman on 10/16/2021 01:06 pm
https://eyes.nasa.gov/dsn/dsn.html
Post by: vjkane on 10/16/2021 02:00 pm
With current technology, elemental abundances of surface materials can be determined by gamma-ray and neutron spectroscopy, which require station-keeping with a Trojan asteroid for a considerable length of time to build up the necessary signal to noise. Complete high-resolution imaging of the rendezvous targets will also not be possible, and precise mass determination from radio tracking is more difficult from a single flyby. Lucy’s advantage, through clever tour design, is that a large number of Trojan asteroids of diverse spectral types will be visited, and on a Discovery budget. A future New Frontiers–class mission to the Trojan asteroids could potentially take advantage of technology development, such as advanced solar-electric propulsion, which could permit extended rendezvous at multiple targets, in the manner of the Dawn mission to Vesta and Ceres. However, selecting a Trojan tour mission in NF5 would not be in keeping with the optimum program balance among mission targets and types recommended strongly in V&V. Further exploration of the Trojan asteroids is justifiable on scientific grounds, but the next steps, beyond Lucy, would be best left for determination by the forthcoming decadal survey.Competing against Lucy and Psyche in that competition was another multiple asteroid flyby mission, MANTIS, that would have examined bodies from most of the major inner solar system (through the asteroid belt) asteroid families. It would have addressed the composition problem by carrying a dust mass spectrometer that would have analyzed the composition of the small particles blasted off the asteroid surface by the nearly constant, minor dust impacts on their surfaces. (The Europa Clipper mission's dust mass spectrometer will rely on the same phenomenon.) The goal was to uniquely tie compositions to families of meteorites. Lucy's proposers did not include this instrument in their proposal.
This extended abstract describes the concept: https://www.hou.usra.edu/meetings/lpsc2020/pdf/2532.pdf (https://www.hou.usra.edu/meetings/lpsc2020/pdf/2532.pdf)
My understanding is that MANTIS was judged to be fully selectable in both that competition and in the following one (that resulted in the selection of VERITAS and DAVINCI+). MANTIS is my favorite Category 1 (fully selectable) Discovery concept that never was selected.
Post by: redliox on 10/16/2021 02:33 pm
Using the original Trojan, 624 Hektor, as an example, how much is known about binary/contact asteroids? Are there implications to how those form that could complement formation theories? I imagine a lot of scientists would be stunned to find a binary that was half KBO and half rocky.
Post by: Blackstar on 10/16/2021 03:30 pm
Between Blackstar's and Vjkane's posts, it sounds like Lucy's expedition to the Trojans might only be a prelude to greater interest in them.
Having hung around with a bunch of planetary scientists for the past year (well, "hung around" meaning dozens of Zoom meetings), I'm still somewhat mystified by the level of interest in asteroids. I don't understand the science that well. But one of their selling points is that they can help to answer some of the more fundamental questions about the creation and early evolution of the solar system. So while an individual rock might seem kinda boring to those of us who are not scientists, they can answer big questions. Also, they are really diverse and every one seems to offer surprises. If we encountered a bunch that were very similar, there would be much less of a case for doing more of these missions.
I think that in the case of Lucy, the science team made a good case that there was a lot of value in visiting several Trojans. I don't know if you could argue that there is a better case for doing that than the New Frontiers case for visiting just one and studying it closer. But I think they made a good case on their own. The only concern that I have heard--and I don't know the validity--is that the flybys might be so quick that they won't provide a lot of useful data. However, countering that, I recently heard that there may be many more flyby opportunities after the initial planned ones. So the mission could provide a decent surveillance of the Trojan population, and it might turn up something so surprising that it makes the case for an eventual rendezvous mission to one or more of them.
I don't have much interest in asteroids in general except for Phobos and Deimos. I'm really interested in Japan's MMX mission and very excited that we will finally get answers to the question of their origin.
Post by: redliox on 10/16/2021 09:35 pm
I don't have much interest in asteroids in general except for Phobos and Deimos. I'm really interested in Japan's MMX mission and very excited that we will finally get answers to the question of their origin.
Ditto. They seem to be oddballs and the asteroid theory has been perpetually in question from such smooth, circular orbits. But, in short, they're the least explored aspect of Mars and little mysteries in a similar manner the Trojans are to both asteroids and Jupiter.
Post by: Don2 on 10/16/2021 09:37 pm
There are other missions trying to study proto-planetary disc materials. Carbonaceous chondrites contain material which has been lightly processed by exposure to water, probably as a result of hydrothermal activity on their parent body. The volatile compounds have been lost but the high melting point stuff still remains.
Comets still have their volatiles and are probably less processed than carbonaceous chondrites. Trojan asteroids should still retain their original water and they might be even more pristine because they have never had cometary activity.
I think the decadal should drop any specific references to Trojans but should retain the objective of accessing well preserved primitive solar system materials. A cometary sample return mission is probably the most promising unfunded opportunity. Future study of the Trojans should wait for the Lucy results.
Post by: Zed_Noir on 10/17/2021 11:37 am
<snip>
Having hung around with a bunch of planetary scientists for the past year (well, "hung around" meaning dozens of Zoom meetings), I'm still somewhat mystified by the level of interest in asteroids.
<snip>
My guesses at the reasons for level of interest in asteroids.
First the level of funding required for asteroid missions is less than for a destination at an outer system planet locale. The shorter time for the completion of primary mission. Finally it is easier to proposed asteroid missions that don't have to deal with harsh radiation environments or EDL methods, just mostly which optical instruments will be used.
Mercury and Venus missions will require near New Frontier funding levels in the future, IMO. As well the DAVINCI+ and VERITAS missions make further Venusian Discovery class mission selection harder.
Mars missions will be sidelined until Mars Sample Return is well under way.
Lunar missions is effectively part of the Artemis program for now.
Post by: Welsh Dragon on 10/17/2021 03:54 pm
Post by: daedalus1 on 10/17/2021 04:14 pm
Personally I'm mystified why someone wouldn't be excited about this mission. Far more exciting to me than yet another Mars mission.
Probably because there is more varied geology on Mars. And there is a realistic possibility of humans walking on Mars.
So yo don't have to be mystified any more.
Post by: vjkane on 10/17/2021 04:51 pm
The mission's key goal is to establish that there is a diversity and relate the bodies to possible origin locations. While there will be observations related to specific body evolutions, that's not the primary goal of the mission.
Also, there was a mention below of a possible extended mission. The PI has stated that the spacecraft can continue to cycle through the asteroid belt and the Trojan populations. I believe he mentioned that they had identified something like 20 candidate objects, of which on Psyche was specifically named. He also noted that this would no longer be a priority extended target for obvious reasons. The limitation on the extended mission will be the fuel since targeting a specific body requires a fair amount of fuel.
The mission's scientific goal from the paper: "The Trojan asteroids were long thought to be a population that formed near Jupiterʼs orbital distance, representing the composition of the nebula near that location. Thus, it is a surprise that Earth-based observations show that they are different from one another This unexpected diversity may be understood in the context of a class of models developed within the last 15 yr or so, which suggest that the objects currently found in the Trojan swarms were originally formed far beyond their current home (at ∼15–30 au), and were transported to their current locations by early orbital evolution of the giant planet orbit… These models suggest that the observed diversity of Trojans is the result of the fact that they originated over a large range of heliocentric distances with varying physical and compositional conditions. Understanding the diversity of Trojans, by interrogating as many observables as possible, will allow us to determine whether these ideas are true, and if true, allow us to constrain the orbital evolution of the giant planets. If Lucy proves these ideas incorrect, it will provide vital clues to develop new hypotheses. "
The paper is open access and available here: https://iopscience.iop.org/article/10.3847/PSJ/abf840/meta (https://iopscience.iop.org/article/10.3847/PSJ/abf840/meta)
Post by: eeergo on 10/17/2021 08:21 pm
https://twitter.com/Dr_ThomasZ/status/1449823392333508614
Post by: Rondaz on 10/18/2021 11:48 am
Karen Fox Posted on October 17, 2021
Following a successful launch on Oct. 16, 2021, analysis of NASA’s Lucy spacecraft systems show the spacecraft is operating well and is stable. Lucy’s two solar arrays have deployed, and both are producing power and the battery is charging. While one of the arrays has latched, indications are that the second array may not be fully latched. All other subsystems are normal. In the current spacecraft attitude, Lucy can continue to operate with no threat to its health and safety. The team is analyzing spacecraft data to understand the situation and determine next steps to achieve full deployment of the solar array.
https://blogs.nasa.gov/lucy/2021/10/17/lucy-spacecraft-healthy-solar-arrays-being-analyzed/
Post by: Rondaz on 10/18/2021 12:30 pm
https://twitter.com/planet4589/status/1449923233927639047
Post by: abaddon on 10/18/2021 02:57 pm
Any informed thoughts on what a latch failure might mean, if they are unable to correct it?
Post by: abaddon on 10/18/2021 02:59 pm
Personally I'm mystified why someone wouldn't be excited about this mission. Far more exciting to me than yet another Mars mission.I'm mystified when I got to a modern art museum why a blank canvas is worth more than I will make in my lifetime. Different strokes for different folks, but I don't really see a need to "wonder" why my preferences aren't the preferences of others.
(I definitely find the prospect of the discoveries from this mission exciting, for the record).
Post by: redliox on 10/18/2021 03:12 pm
Post by: ccdengr on 10/18/2021 03:25 pm
Any informed thoughts on what a latch failure might mean, if they are unable to correct it?If there's negligible reduction of power production, possibly no impact. Mars Global Surveyor flew its whole mission with an unlatched solar array, though it impacted the depth of aerobraking and made orbit lowering take longer. (Obviously a different array design.)
I can't tell if the Ultraflex array can reverse the deployment drive motor or not. Here's an old paper but I don't know how the specifics may have changed. https://ntrs.nasa.gov/api/citations/19940006927/downloads/19940006927.pdf
If there is a big hit on power, it could probably be managed by taking longer to play data back to allow more recharge time between comm sessions. I assume they don't rely on array power during an actual flyby, being able to run off batteries, but I don't know how the batteries are sized.
Post by: Hungry4info3 on 10/19/2021 04:11 am
Post by: Phil Stooke on 10/19/2021 06:59 am
Post by: edzieba on 10/19/2021 10:11 am
My main concern is if the solar array is out there dangling, how much is that going to be an issue for instrument pointing stability? Fortunately this spacecraft has a scan platform that can move independently, so I hope it won't be too much.Depending on what "did not fully latch" entails (completely loose and flapping in the solar breeze? Only single lock engaged? Seated but not latched?) there could be limits placed on thruster firings to reduce force applied to the array to minimise the chance of unintentionally re-closing the array (e.g. no rapid starts/stops to rolls). That could potentially impact pointing during flybys at close ranges, leading to more distance flybys being chosen or loss of observation during the start or end of a flyby due to maximum rotation rate limits being imposed.
On the other hand, depending on what exactly went wrong with the the latching there's the chance and 'angles and dangles' could be performed to attempt to reseat the panel and give another opportunity for the latches to close. That comes at risk to the mission if it results in the array ending up in an unlatch but less open state than it is currently in.
More analysis of the exact state of the array is needed first.
Post by: Zed_Noir on 10/19/2021 08:38 pm
....
Fortunately this spacecraft has a scan platform that can move independently
....
Wonder if the scan platform can imaged the solar array with the latch issue?
Post by: meekGee on 10/19/2021 10:42 pm
Are we seriously doing this here?There seems plenty of variety in geology of asteroids. To me manned missions to an asteroid are actually more viable than going to Mars. TBH the more I hear about the difficulties in getting to Mars especially on the health side I am starting to wonder if going to an asteroid after the Moon might not be a better option for now.Personally I'm mystified why someone wouldn't be excited about this mission. Far more exciting to me than yet another Mars mission.
Probably because there is more varied geology on Mars. And there is a realistic possibility of humans walking on Mars.
So yo don't have to be mystified any more.
Note the previous poster explained why some people are interested. You OTOH are starting a full blown argument over Moon vs Mars vs Asteroids. Nobody even mentioned the moon beforehand.
Done preaching.
Post by: deadman1204 on 10/20/2021 12:11 am
no, there are no cameras set up to image the spacecraft itself.....
Fortunately this spacecraft has a scan platform that can move independently
....
Wonder if the scan platform can imaged the solar array with the latch issue?
Post by: Star One on 10/20/2021 06:53 am
Original post removed as I mistakenly thought I was in the discussion not updates thread. IMHO though all these posts seem OT for this thread.Are we seriously doing this here?There seems plenty of variety in geology of asteroids. To me manned missions to an asteroid are actually more viable than going to Mars. TBH the more I hear about the difficulties in getting to Mars especially on the health side I am starting to wonder if going to an asteroid after the Moon might not be a better option for now.Personally I'm mystified why someone wouldn't be excited about this mission. Far more exciting to me than yet another Mars mission.
Probably because there is more varied geology on Mars. And there is a realistic possibility of humans walking on Mars.
So yo don't have to be mystified any more.
Note the previous poster explained why some people are interested. You OTOH are starting a full blown argument over Moon vs Mars vs Asteroids. Nobody even mentioned the moon beforehand.
Done preaching.
Post by: tyrred on 10/20/2021 07:04 am
Lucy is one of the more intriguing missions to me, and I would just like to know more TM.
Post by: fast on 10/20/2021 08:32 am
My main concern is if the solar array is out there dangling, how much is that going to be an issue for instrument pointing stability? Fortunately this spacecraft has a scan platform that can move independently, so I hope it won't be too much.Depending on what "did not fully latch" entails (completely loose and flapping in the solar breeze? Only single lock engaged? Seated but not latched?) there could be limits placed on thruster firings to reduce force applied to the array to minimise the chance of unintentionally re-closing the array (e.g. no rapid starts/stops to rolls). That could potentially impact pointing during flybys at close ranges, leading to more distance flybys being chosen or loss of observation during the start or end of a flyby due to maximum rotation rate limits being imposed.
On the other hand, depending on what exactly went wrong with the the latching there's the chance and 'angles and dangles' could be performed to attempt to reseat the panel and give another opportunity for the latches to close. That comes at risk to the mission if it results in the array ending up in an unlatch but less open state than it is currently in.
More analysis of the exact state of the array is needed first.
Is there any photos of spacecraft exterior after arrays deployment?
Post by: edzieba on 10/20/2021 12:48 pm
Quote
After successful separation from the rocket on Oct. 16, NASA’s Lucy spacecraft deployed both solar arrays. Soon after deployment, NASA received confirmation that one of the solar arrays was fully deployed and latched. Analysis currently shows the second solar array is partially unfurled. The team continues to look at all available engineering data to establish how far it is deployed. That solar array is generating nearly the expected power when compared to the fully deployed wing. This power level is enough to keep the spacecraft healthy and functioning.
The Lucy spacecraft has remained in safe mode and is transitioning to cruise mode today. This mode has increased autonomy and spacecraft configuration changes, which is necessary as Lucy moves away from Earth. The team continues its assessment and an attempt to fully deploy the solar array is planned no earlier than the end of next week.
Lucy has successfully fired thrusters to slew the spacecraft with the current array configuration and will safely continue with desaturation maneuvers — small thruster firings to manage the spacecraft’s momentum — as planned.
The operations team has temporarily postponed the deployment of the instrument pointing platform to focus on resolving solar array deployment. The operations team continues to execute all other planned post-launch activities. The ULA Atlas V rocket delivered Lucy precisely to the target point at separation, and so a backup maneuver called the Trajectory Correction Maneuver (TCM-1) is unnecessary and has therefore been canceled. The first maneuver will now be what’s known as TCM-2, currently scheduled for mid-December.
The project is evaluating whether there are any long-term implications to other scheduled activities.
Post by: Star One on 10/20/2021 01:03 pm
Yeah this thread has great discussion, but does not adhere to what some would expect from an update thread. Which thread is the discussion thread, again?TBH I am a bit confused now as it looks like it has two update threads this and one the launch thread. Does it have a dedicated discussion thread as such or is the launch thread the discussion thread?
Lucy is one of the more intriguing missions to me, and I would just like to know more TM.
Post by: fast on 10/20/2021 01:29 pm
New update: https://blogs.nasa.gov/lucy/2021/10/19/nasa-team-remains-focused-on-lucys-solar-arrays/ (https://blogs.nasa.gov/lucy/2021/10/19/nasa-team-remains-focused-on-lucys-solar-arrays/)QuoteAfter successful separation from the rocket on Oct. 16, NASA’s Lucy spacecraft deployed both solar arrays. Soon after deployment, NASA received confirmation that one of the solar arrays was fully deployed and latched. Analysis currently shows the second solar array is partially unfurled. The team continues to look at all available engineering data to establish how far it is deployed. That solar array is generating nearly the expected power when compared to the fully deployed wing. This power level is enough to keep the spacecraft healthy and functioning.
The Lucy spacecraft has remained in safe mode and is transitioning to cruise mode today. This mode has increased autonomy and spacecraft configuration changes, which is necessary as Lucy moves away from Earth. The team continues its assessment and an attempt to fully deploy the solar array is planned no earlier than the end of next week.
Lucy has successfully fired thrusters to slew the spacecraft with the current array configuration and will safely continue with desaturation maneuvers — small thruster firings to manage the spacecraft’s momentum — as planned.
The operations team has temporarily postponed the deployment of the instrument pointing platform to focus on resolving solar array deployment. The operations team continues to execute all other planned post-launch activities. The ULA Atlas V rocket delivered Lucy precisely to the target point at separation, and so a backup maneuver called the Trajectory Correction Maneuver (TCM-1) is unnecessary and has therefore been canceled. The first maneuver will now be what’s known as TCM-2, currently scheduled for mid-December.
The project is evaluating whether there are any long-term implications to other scheduled activities.
Ok, I suppose they have no photos how the arrays look like at the moment.
Solar arrays were a major concern for this mission, its dumb from LM not to have small cams to control critical components deployment.
Post by: Jim on 10/20/2021 01:41 pm
Solar arrays were a major concern for this mission, its dunb from LM not to have small cams to control critical components deployment.
That is wrong. Cameras have nothing to do with controlling components nor would they insure successful deployments.
Post by: eeergo on 10/20/2021 01:45 pm
Solar arrays were a major concern for this mission, its dunb from LM not to have small cams to control critical components deployment.
That is wrong. Cameras have nothing to do with controlling components nor would they insure successful deployments.
They certainly would help in this situation. Doubt they have a set of diagnostic sensors that gives them an accurate, complete overview of what the array looks like at this time, or what it will look like after troubleshooting attempts, thruster firings or other maneuvers. Being flexible and 360-degree deployable, there's quite a few degrees of freedom they might want to look at. There are other spacecraft that do use engineering cameras for appendage deployment, and they appeared to have served them well (Chang'es, Tianwen, BepiColombo, Rosetta, Hayabusas...)
Post by: Jim on 10/20/2021 01:55 pm
They certainly would help in this situation.
Not really. A camera would unlikely see the latching mechanism.
Doubt they have a set of diagnostic sensors that gives them an accurate, complete overview of what the array looks like at this time, or what it will look like after troubleshooting attempts, thruster firings or other maneuvers
Yes they do. The power output is proportional to amount of deployment.
Post by: eeergo on 10/20/2021 02:01 pm
They certainly would help in this situation. Doubt they have a set of diagnostic sensors that gives them an accurate, complete overview of what the array looks like at this time, or what it will look like after troubleshooting attempts, thruster firings or other maneuvers
Yes they do. The power output is proportional to amount of deployment.
A camera would unlikely see the latching mechanism.
Power output will be sinusoidally-dependent on the inclination of the cells with respect to the Sun vector - it won't be too sensitive when deployment is near-complete (say, between 325 and 360 degrees of deployment boom rotation). Also, you'll be assuming that the folding of the array is still unaltered from the nominal pattern, which may not be the case if it deployed completely, failed to latch, and went back - or if something more radical happened to the array, such as tears or snags.
Post by: ccdengr on 10/20/2021 03:13 pm
Wonder if the scan platform can imaged the solar array with the latch issue?The Terminal Tracking Cameras on the scan platform (11x8.2 degree FOV) are focused at infinity but might be able to take out-of-focus images if the platform can be pointed appropriately, I don't know much about its range of travel.
https://www.researchgate.net/publication/354107007_Lucy_Mission_to_the_Trojan_Asteroids_Instrumentation_and_Encounter_Concept_of_Operations
Post by: matthewkantar on 10/20/2021 03:16 pm
Post by: edzieba on 10/20/2021 04:01 pm
As well as inferred deployment from geometric models and power output, you also have encoders (e.g. that big central array joint) and 'home' sensors for the latch mechanisms for both the 'fan-out' portion of the deployment sequence and the initial 'fold-out'.
Post by: deadman1204 on 10/20/2021 04:18 pm
But how many dozens of cameras would that be to cover all the places you might need one? How much mass, power, bandwidth, and money go to all these contingency cameras that will probably never get used?
Post by: ccdengr on 10/20/2021 04:25 pm
They would once you told them what science instrument(s) you'd be removing to add them.I remember looking at the Mars Climate Orbiter spacecraft and seeing a hunk of ballast that had a mass several times that of the science instrument I was working on at the time, so never say never. But engineering cameras remain a hard sell.
Post by: matthewkantar on 10/20/2021 04:26 pm
Maybe some energetic kids could start a company to make a one kilo, mission agnostic, cold gas propelled, free flying, camera drone. If it's not needed, fine. If a need comes up, deploy it and ditch it the next time the probe maneuvers.
Post by: mmonty on 10/20/2021 04:30 pm
Post by: HVM on 10/20/2021 04:33 pm
https://www.youtube.com/watch?v=6vjK9vGEw5Q
Depending to how far it has unfolded those panels, those don't point to the wanted direction until whole thing is fully open, and panels are flat.
Post by: Jim on 10/20/2021 04:40 pm
cameras can weight very very little. The Chinese seem to be throwing them in here and there with interesting results. Webb is going up with zero engineering cameras, hope they won't be needed.
Maybe some energetic kids could start a company to make a one kilo, mission agnostic, cold gas propelled, free flying, camera drone. If it's not needed, fine. If a need comes up, deploy it and ditch it the next time the probe maneuvers.
That would require a whole different receiver and a latching and deployment mechanism. Also, a transmitter. And it can't be remote controlled, it would have to be semi autonomous. Nobody is going to want that around there spacecraft.
Not really a viable idea.
Post by: Jim on 10/20/2021 04:53 pm
They would once you told them what science instrument(s) you'd be removing to add them.I remember looking at the Mars Climate Orbiter spacecraft and seeing a hunk of ballast that had a mass several times that of the science instrument I was working on at the time, so never say never. But engineering cameras remain a hard sell.
Because it was a spinner
Post by: Jim on 10/20/2021 04:54 pm
cameras can weight very very little.
The hardware to integrate their output into the telemetry stream isn't
Post by: meekGee on 10/20/2021 05:53 pm
They would once you told them what science instrument(s) you'd be removing to add them.Except nowadays cameras are like a gram. And this would be a health-monitoring camera, not a science instrument, needed mostly during the deployment sequences, and if it's lost, the mission is not harmed. It's a "good to have" at a negligible cost.
As well as inferred deployment from geometric models and power output, you also have encoders (e.g. that big central array joint) and 'home' sensors for the latch mechanisms for both the 'fan-out' portion of the deployment sequence and the initial 'fold-out'.
Post by: deadman1204 on 10/20/2021 05:57 pm
Please consider that its short more complicated than you realize.
Post by: matthewkantar on 10/20/2021 06:12 pm
All these things can break, become power drains, cause unexpected interference, all sorts of thing.
Please consider that its short more complicated than you realize.
The Chinese do not seem to have taken this wisdom on board.
Post by: freddo411 on 10/20/2021 07:23 pm
Solar arrays were a major concern for this mission, its dunb from LM not to have small cams to control critical components deployment.
That is wrong. Cameras have nothing to do with controlling components nor would they insure successful deployments.
The attitude towards other engineering approaches is highly negative and discouraging.
Post by: freddo411 on 10/20/2021 07:24 pm
Curiosity, opportunity, perseverance all have multiple engineering camsThey would once you told them what science instrument(s) you'd be removing to add them.Except nowadays cameras are like a gram. And this would be a health-monitoring camera, not a science instrument, needed mostly during the deployment sequences, and if it's lost, the mission is not harmed. It's a "good to have" at a negligible cost.
As well as inferred deployment from geometric models and power output, you also have encoders (e.g. that big central array joint) and 'home' sensors for the latch mechanisms for both the 'fan-out' portion of the deployment sequence and the initial 'fold-out'.
Post by: meekGee on 10/20/2021 07:30 pm
Makes sense.Curiosity, opportunity, perseverance all have multiple engineering camsThey would once you told them what science instrument(s) you'd be removing to add them.Except nowadays cameras are like a gram. And this would be a health-monitoring camera, not a science instrument, needed mostly during the deployment sequences, and if it's lost, the mission is not harmed. It's a "good to have" at a negligible cost.
As well as inferred deployment from geometric models and power output, you also have encoders (e.g. that big central array joint) and 'home' sensors for the latch mechanisms for both the 'fan-out' portion of the deployment sequence and the initial 'fold-out'.
Compared with designs that are even 10-20 years older (not to mention more), the decision to add more sensors such as cameras has got to become easier.
A non-science camera and associated wiring is such a small mass penalty, and only consumes power and bandwidth when used... I'm sure the group trying to replicate/model/overcome this issue would have very much appreciated a view of the panel in its current state, with or without the latch
Post by: ccdengr on 10/20/2021 07:30 pm
MCO was not a spinner.I remember looking at the Mars Climate Orbiter spacecraft and seeing a hunk of ballast that had a mass several times that of the science instrument...Because it was a spinner
At any rate, this whole engineering camera argument is moot for Lucy because it doesn't have any. TTCAM might be able to see something, not clear how diagnostic it would be if it's even feasible.
Post by: Comga on 10/20/2021 08:12 pm
MCO was not a spinner.I remember looking at the Mars Climate Orbiter spacecraft and seeing a hunk of ballast that had a mass several times that of the science instrument...Because it was a spinner
At any rate, this whole engineering camera argument is moot for Lucy because it doesn't have any. TTCAM might be able to see something, not clear how diagnostic it would be if it's even feasible.
Thank you
People can take a break from thinking they are smarter, have the perfect equivalent condition, foresaw this particular failure, etc.
The Lucy team is a bunch of smart people working difficult engineering issues and making tough choices.
(I am proud to be able to say I know and have worked with some of them.)
I look forward to hearing how they deal with this issue.
However, I do wish that beyond saying "That solar array is generating nearly the expected power when compared to the fully deployed wing." they gave a percentage.
Post by: zubenelgenubi on 10/20/2021 08:22 pm
I will now say the magic word: A-la-peanut-butter-sandwiches!
It is done! ✔
TBH I am a bit confused now as it looks like it has two update threads this and one the launch thread. Does it have a dedicated discussion thread as such or is the launch thread the discussion thread?
Post by: Star One on 10/20/2021 08:25 pm
Watch with amazement as the AmazingThank you. I will not be re-instating my deleted post as I can see it was utterly OT. So apologies again.MumfordModerator waves his magicwand and transforms the Lucy program updates thread into the Lucy updates AND discussion thread.
I will now say the magic word: A-la-peanut-butter-sandwiches!
It is done!
TBH I am a bit confused now as it looks like it has two update threads this and one the launch thread. Does it have a dedicated discussion thread as such or is the launch thread the discussion thread?
Post by: jaredhead on 10/20/2021 08:29 pm
...However, I do wish that beyond saying "That solar array is generating nearly the expected power when compared to the fully deployed wing." they gave a percentage.
Haven't seen it posted here but per Spaceflight Now: https://spaceflightnow.com/2021/10/18/nasa-officials-optimistic-lucy-asteroid-mission-will-overcome-solar-array-snag/
Quote
...“We’re very happy to report that we are getting most of the power we expected at this point in the mission,” said Joan Salute, associate director for flight programs at NASA’s planetary science division. “It’s not 100%, but it is fairly close. So that is great news.’
In an interview with Spaceflight Now, Salute said the power output from the solar arrays appears to be “most likely above 90%” of the expected level of 18,000 watts...
Also, if I recall correctly, these are similar to the arrays that are used on Cygnus.
Post by: Comga on 10/20/2021 09:04 pm
...However, I do wish that beyond saying "That solar array is generating nearly the expected power when compared to the fully deployed wing." they gave a percentage.
Haven't seen it posted here but per Spaceflight Now: https://spaceflightnow.com/2021/10/18/nasa-officials-optimistic-lucy-asteroid-mission-will-overcome-solar-array-snag/ (https://spaceflightnow.com/2021/10/18/nasa-officials-optimistic-lucy-asteroid-mission-will-overcome-solar-array-snag/)Quote...“We’re very happy to report that we are getting most of the power we expected at this point in the mission,” said Joan Salute, associate director for flight programs at NASA’s planetary science division. “It’s not 100%, but it is fairly close. So that is great news.’
In an interview with Spaceflight Now, Salute said the power output from the solar arrays appears to be “most likely above 90%” of the expected level of 18,000 watts...
Also, if I recall correctly, these are similar to the arrays that are used on Cygnus.
Yes, they are both "Ultraflex" arrays from Northrup-Orbital-ATK but the ones on Cyugnus (https://optics.org/news/6/12/15) are 3.7 meters in diameter. These on Lucy are 7.3 meters in diameter, "the (largest) circular power arrays to ever fly in space", a significant scale-up.
(SFN left out a pretty important word: largest)
And that illustration is terrible. When latched, the Ultraflex arrays are quite flat.
At 90% power, the gap would be equivalent to about one of the ten sections of the array.
And I wonder why Salute, the associate director for flight programs at NASA’s planetary science division, said "...most likely above 90%." They have data.
Thanks for the linked SFN article.
Post by: meekGee on 10/20/2021 09:40 pm
All these things can break, become power drains, cause unexpected interference, all sorts of thing.You don't know what I realize...
Please consider that its short more complicated than you realize.
But consider that the odds that a mechanical unfurling mechanism will break are much higher, and unlike an inspection camera, there's no way to make it fail unobstructively.
Right now the mission is at some risk, and an inspection camera would have helped in analyzing the situation.
Post by: Jim on 10/20/2021 09:41 pm
MCO was not a spinner.
It flew on a 3 stage Delta II. Every spacecraft that flew on 3 stage Delta was spun to at least 50 rpm and likely more and hence had to be statically and dynamically balanced. Whether thery despun after separation doesn't really matter, the design was more affected by this than anything.
Post by: Jim on 10/20/2021 09:42 pm
..... at a negligible cost.
That is blatantly untrue.
Post by: Jim on 10/20/2021 09:44 pm
A non-science camera and associated wiring is such a small mass penalty, and only consumes power and bandwidth when used...
Unsubstantiated handwaving.
Post by: Jim on 10/20/2021 09:48 pm
Curiosity, opportunity, ..... all have multiple engineering cams
They did not look at the spacecraft but rather outward and were more additional navigation type. The cameras on the arms were used for investigations of the rover.
Mars2020 had extra cameras because they were part of an experiment and there was available mass not because MSL issues that drove the need.
Post by: meekGee on 10/20/2021 09:57 pm
Agreed - you're basically saying an inspection camera would be super expensive and not worth it without really saying why, and in the face of a mission where obviously there's some failure and the operators only have a partial picture of the state of the array.A non-science camera and associated wiring is such a small mass penalty, and only consumes power and bandwidth when used...
Unsubstantiated handwaving.
Post by: ccdengr on 10/20/2021 09:58 pm
My only point about MCO ballast is that mass is not the only factor.
And the point that cameras wouldn't invariably allow a problem to be fixed is valid.
Post by: meekGee on 10/20/2021 10:00 pm
- Is the latching mechanism practically at the latching position but isn't latching?
- Is the array not fully extended? If not - is the problem concentrated in one of the folds or distributed evenly?
- Is the fabric behaving as expected? Is there an unexpected fold or a snag?
Post by: Jim on 10/20/2021 10:01 pm
Right now the mission is at some risk, and an inspection camera would have helped in analyzing the situation.
Not necessarily. And what do you propose to leave off to cover all the cameras because there has to be more than one (there are two arrays) and likely mounting locations are not going to give 100 % view of whole arrays.
Lets say 4 cameras per array. Power and data harnessing, mounting hardware, MLI, video box, etc, I bet it would be close to 1% of the dry mass of the spacecraft. $ cost is going to be more than than mass.
a. It isn't going to ensure the array is going to deploy
b. And it isn't necessarily going to find the problem
c. It isn't going to fix the problem.
d. It doesn't reduce the risk to the mission, yet it takes resources from the mission
Substantiated.
Post by: meekGee on 10/20/2021 10:07 pm
Right now the mission is at some risk, and an inspection camera would have helped in analyzing the situation.
Not necessarily. And what do you propose to leave off to cover all the cameras because there has to be more than one (there are two arrays) and likely mounting locations are not going to give 100 % view of whole arrays.
Lets say 4 cameras per array. Power and data harnessing, mounting hardware, MLI, video box, etc, I bet it would be close to 1% of the dry mass of the spacecraft.
a. It isn't going to ensure the array is going to deploy
b. And it necessarily going to find the problem
c. It doesn't reduce the risk to the mission, yet it takes resources from the mission
That's why I emphasized "if it's designed into the array early". The array itself by definition is full of routing (from the cells). So adding "wiring and harnessing" has zero penalty - you just add instrumentation/communication traces when you design it.
The cameras themselves don't have to survive years in space, and so really are just single chips with integrated lenses, again built into the array and not requiring their own housings and mountings.
Keep in mind if the camera fails, you lose inspection ability, not any mission objectives. The controller chip will be built to isolate any failures. You don't even need redundancy, just fail isolated.
Agreed on B.
Disagreed on C. Having a holistic view of the array, especially since it's such a flimsy mechanical origami piece, can help in unsticking it and resolving the issue, or can help in developing alternate flight rules if it will remain undeployed, and can monitor system response to the new flight rules.
Post by: Jim on 10/20/2021 11:00 pm
a.
That's why I emphasized "if it's designed into the array early". The array itself by definition is full of routing (from the cells). So adding "wiring and harnessing" has zero penalty - you just add instrumentation/communication traces when you design it.
The cameras themselves don't have to survive years in space, and so really are just single chips with integrated lenses, again built into the array and not requiring their own housings and mountings.
Keep in mind if the camera fails, you lose inspection ability, not any mission objectives. The controller chip will be built to isolate any failures. You don't even need redundancy, just fail isolated.
Agreed on B.
Disagreed on C. Having a holistic view of the array, especially since it's such a flimsy mechanical origami piece, can help in unsticking it and resolving the issue, or can help in developing alternate flight rules if it will remain undeployed, and can monitor system response to the new flight rules.
A. The cameras go on the body of the spacecraft to watch the arrays. Regardless on the arrays or body, still require harnesses separate and isolated. There is no zero penalty. There are no traces. it is all wires.
C. No, it doesn't reduce the risk of a bad deployment. And that can be done without camera.
Post by: edzieba on 10/20/2021 11:03 pm
- If the array is intact and the problem is solvable by moving the joints, then the encoders (and inferred deployment state via panel power output) give you all the information on array state you need
- If the array is damaged in a way that prevents fixing it by moving the joints (e.g. stuck joint, flexible panel element has torn or detached, etc), then a camera does nothing other than give you a photo of your unfixable problem.
Post by: meekGee on 10/20/2021 11:07 pm
Reduce the risk to bad deployment was A. We're in C: reduce risk to mission in the face of a bad deployment.a.
That's why I emphasized "if it's designed into the array early". The array itself by definition is full of routing (from the cells). So adding "wiring and harnessing" has zero penalty - you just add instrumentation/communication traces when you design it.
The cameras themselves don't have to survive years in space, and so really are just single chips with integrated lenses, again built into the array and not requiring their own housings and mountings.
Keep in mind if the camera fails, you lose inspection ability, not any mission objectives. The controller chip will be built to isolate any failures. You don't even need redundancy, just fail isolated.
Agreed on B.
Disagreed on C. Having a holistic view of the array, especially since it's such a flimsy mechanical origami piece, can help in unsticking it and resolving the issue, or can help in developing alternate flight rules if it will remain undeployed, and can monitor system response to the new flight rules.
A. The cameras go on the body of the spacecraft to watch the arrays. Regardless on the arrays or body, still require harnesses separate and isolated. There is no zero penalty. There are no traces. it is all wires.
C. No, it doesn't reduce the risk of a bad deployment. And that can be done without camera.
Also, if the cameras help develop a plan to fully deploy the array, it's arguably even fixing it at the A level.
--
Inspection cameras, even if on the body (not at all a certainty, and can be on the part of the array that's attached to the spacecraft) can be minor. The earlier they are designed in, the more they can make use if existing harnesses, traces, mount points, enclosures, etc.
Nothing is entirely without cost, but there's plenty benefit here, as is obvious from events.
Post by: ccdengr on 10/20/2021 11:45 pm
What useful information is a camera going to give you that joint encoders are not?What makes you think these arrays have anything more than limit switches on the latch?
I don't know what they have, but that would be my guess.
They certainly imaged the Galileo failed antenna as best they could. but it didn't help.
Post by: meekGee on 10/21/2021 02:33 am
What useful information is a camera going to give you that joint encoders are not?First, for each of the many encoders you'll need for a complete picture of the spokes you can put up the same arguments as the ones against the camera: power, weight bandwidth, routing, failure modes of the sensor...
- If the array is intact and the problem is solvable by moving the joints, then the encoders (and inferred deployment state via panel power output) give you all the information on array state you need
- If the array is damaged in a way that prevents fixing it by moving the joints (e.g. stuck joint, flexible panel element has torn or detached, etc), then a camera does nothing other than give you a photo of your unfixable problem.
Second, encoders only paint a partial picture. If the problem is in the flex membrane, its important to look at it to develop a salvage/repair plan. Did it stick to itself? Is there a tear? A loose piece that's snagging? Different scenarios will ask for different rescue plans.
And if it can't be fixed, a camera will tell you how it is responding to various thrust commands or attitude change commands, which will augment what your inertial sensors are telling you.
Point measurement sensors like encoders complement what a camera provides, not replace it. And like a camera, if they're designed in early, their cost is negligible.
Post by: Phil Stooke on 10/21/2021 02:38 am
Did they? I have no recollection of that. Can you give more details? It would be fascinating to know more.
Post by: mn on 10/21/2021 04:05 am
This thread is very illuminating. I had no idea that the people who designed Lucy were so incredibly stupid and inept.
I have no doubts about the people who designed Lucy.
It's just dummies like me who can't understand why there wouldn't be a camera, and there is nothing wrong with asking, it doesn't imply disrespect for the engineers who built Lucy. And the answers giving so far in this thread have been unconvincing.
Post by: Comga on 10/21/2021 04:48 am
This thread is very illuminating. I had no idea that the people who designed Lucy were so incredibly stupid and inept.
I have no doubts about the people who designed Lucy.
It's just dummies like me who can't understand why there wouldn't be a camera, and there is nothing wrong with asking, it doesn't imply disrespect for the engineers who built Lucy. And the answers giving so far in this thread have been unconvincing.
Everything about space system design, especially deep space design that needs a projected lifetime of 13 years, is extremely difficult.
(A similar long lifetime requirement was one of the thinks that killed JPL's Pluto Fast Flyby proposal.)
To my knowledge, no Ultraflex array has previously failed to deploy and latch, including those deployed on the Martian surface.
Does someone have a counter-example that would indicate that this was a risk of significant probability?
"Hindsight is 20/20" and it's always sad not to have that extra system to ameliorate the particular anomaly that has occured.
But you can only have them for the most likely and consequential failures, due to limited resources, and to not over-complicate the system to where the probability of success decreases.
We don't yet know the impact of the anomaly, or whether it can be fully resolved, or be sure that a camera would provide any actionable information that is not otherwise available.
But if the final report from the Lucy team says "If only we had a camera!" you can say "I told you so."
Post by: gparker on 10/21/2021 05:09 am
ccdengr: "They certainly imaged the Galileo failed antenna as best they could"
Did they? I have no recollection of that. Can you give more details? It would be fascinating to know more.
No photos of Galileo's antenna were captured. The only data that might be called "imaging" was reduced output from a Sun sensor, which was inferred to be the shadow of one particular antenna rib in a partially-deployed position. The other telemetry used was accelerometer measurements of spacecraft spin rate and wobble, and the electric current drawn by the deployment motors.
The Galileo High Gain Antenna Deployment Anomaly (JPL, 1994)
https://ntrs.nasa.gov/api/citations/19940028813/downloads/19940028813.pdf
Post by: ccdengr on 10/21/2021 05:50 am
ccdengr: "They certainly imaged the Galileo failed antenna as best they could"I have a vague recollection of seeing a very blurry image in AW&ST taken with NIMS if memory serves, but maybe I'm confusing that with the sun sensor data. But I don't think so.
Did they? I have no recollection of that. Can you give more details? It would be fascinating to know more.
Post by: meekGee on 10/21/2021 05:55 am
This thread is very illuminating. I had no idea that the people who designed Lucy were so incredibly stupid and inept.In aerospace, like in every industry, old habits die hard.
Instances of "things that would have been smart to design in" are common without the designers having to be inept.
If you've ever been a part of a development project of any significant size, you know that decisions to introduce things that weren't there in a previous generation are always difficult to make.
And as technology changes, there are always new things that make sense now and didn't make sense a decade ago.
Post by: fast on 10/21/2021 10:44 am
These excuses are ridiculous if a couple of mobile phone cameras are too expensive for 1B USD mission, even more ridiculous if they are expensive for 10B USD Webb if there chance that they can help to diagnose and resolve deployment issue.
At least in this aspect of robotic spaceflight Chinese engineering already have clear superiority over US, probably they know the miracle how to make them simple, light and cheap and now throwing around selfie cams everywhere - moon, mars, deep space.
Post by: edzieba on 10/21/2021 12:22 pm
Only lame excuses from cameras opponents: complexity, weight, price, we never needed it - don’t need now, we always lived in caves, blah blah.And yet interplanetary missions - and satellites in general - continue not to host cameras to observe array deployments. Gee, all those mission designers must be really stupid for not just slapping a camera on, it's so simple!
Expense is not the issue. The issue is adding mass (not just a camera module but all the support hardware to keep it heated, cooled, data handling, signal routing, etc), adding mission complexity, superseding other telemetry for data downlink (cameras take a lot of bandwidth), adding whole extra systems to bring through the engineering cycle, etc.
And all to give you a picture that does nothing more than confirm what your existing telemetry tells you. For failure you can do something about (e.g. moving joints) telemetry is already added. For those you cannot do anything about (e.g. physical damage) the camera does not aid in fixing the unfixable.
Post by: fast on 10/21/2021 12:49 pm
Only lame excuses from cameras opponents: complexity, weight, price, we never needed it - don’t need now, we always lived in caves, blah blah.And yet interplanetary missions - and satellites in general - continue not to host cameras to observe array deployments. Gee, all those mission designers must be really stupid for not just slapping a camera on, it's so simple!
Expense is not the issue. The issue is adding mass (not just a camera module but all the support hardware to keep it heated, cooled, data handling, signal routing, etc), adding mission complexity, superseding other telemetry for data downlink (cameras take a lot of bandwidth), adding whole extra systems to bring through the engineering cycle, etc.
And all to give you a picture that does nothing more than confirm what your existing telemetry tells you. For failure you can do something about (e.g. moving joints) telemetry is already added. For those you cannot do anything about (e.g. physical damage) the camera does not aid in fixing the unfixable.
Please not again about unsurmountable engineering challenge, if true than Chinese are wizards.
Maybe they not stupid, probably more "oldspace" and slow to adapt to the pace of modern electronics technology, current missions design architecture roots from many year ago could be also contributor. Electronics made huge leap last 10 years and now doing every year, .
And please stop repeating this stupid argument that camera will not fix the problem, everyone understands the camera will not fix the problem, like Xray or tomography will not cure the illness, but like every diagnostic tool it could provide critical information to develop efficient fix.
Sure, there other sensors, but sometimes one view is better them tons of numbers.
C’mon, please stop this nonsense excuses, everyone would like to see the picture.
[deleted]
Post by: Jim on 10/21/2021 12:53 pm
How many spacecraft have you designed? How many spacecraft design reviews have you attended?
Post by: edzieba on 10/21/2021 01:02 pm
Please not again about unsurmountable engineering challenge, if true than Chinese are wizards.The Chinese are also not mounting extra engineering cameras. One mission deployed a standalone camera module that operated for a brief period (a few minutes of onboard power). This was a demonstrator for subsatellite carriage and deployment, with the camera payload being incidental.
Post by: matthewkantar on 10/21/2021 02:37 pm
Is there an element of hubris? The idea that the tech is so badass nothing will go wrong?
Cams are useful, they are cheap, they weigh less than a nickel, we will be seeing lots more of them on future missions.
Post by: meekGee on 10/21/2021 03:02 pm
And yet interplanetary missions - and satellites in general - continue not to host cameras to observe array deployments. Gee, all those mission designers must be really stupid for not just slapping a camera on, it's so simple!
....
No need for sarcasm, and it's a false dichotomy - pointing out a design shortfall doesn't mean the designers are inept.
Look at how Virgin Galactic flies. "Auto pilots are stupid" - even after the accident. Same thing. It's not that the engineers are stupid, but it's hard to change how the company views automation.
Or look at commercial aviation... A jetliner taxiing in heavy weather turns into the wrong runway and crashes into construction equipment on take off. Lots of fatalities. Yet any of the passengers, for $10, could have added a navigation system to their rental car that would have prevented that sort of mistake.
And to this day, more than 10 years later, confusion over taxiing instructions continue to occur, even though planes have GPS, and data comms, and everything needed to fix it.
Why? Not because any engineer is inept, but because of inertia, and lines of responsibility, (and not regulation, which is often made the scapegoat)
--
With time, maybe after some more obvious and expensive LoM, you'll see it change, and more modern tools such as cameras incorporated more freely.
Post by: Jim on 10/21/2021 03:33 pm
No need for sarcasm, and it's a false dichotomy - pointing out a design shortfall doesn't mean the designers are inept.
The false dichotomy is stating that there is a design shortfall.
Having cameras doesn't guarantee anything.
Post by: Jim on 10/21/2021 03:34 pm
Didn’t one of the designers of Perseverance say that the inspiration for adding some of the engineering cameras was his kid’s GoPro? Weird way to get news of advances it tech, no?
Is there an element of hubris? The idea that the tech is so badass nothing will go wrong?
Cams are useful, they are cheap, they weigh less than a nickel, we will be seeing lots more of them on future missions.
Wrong. Cameras will be added when resources allow for it. Perseverance had the resources: $ and mass
Post by: meekGee on 10/21/2021 03:39 pm
Nothing guarantees everything.No need for sarcasm, and it's a false dichotomy - pointing out a design shortfall doesn't mean the designers are inept.
The false dichotomy is stating that there is a design shortfall.
Having cameras doesn't guarantee anything.
But deployment mechanisms are always high risk, floppy ones even more so, and a generic analysis/debug tool such as a camera has value.
The trade against complexity/cost etc is a real thing, but with every year, it's trending in only one direction...
Post by: edzieba on 10/21/2021 04:22 pm
And the problem, as multiple people have already stated, is that an image of the failure is not of much - if any - actual help. If it's a fixable problem the telemetry already tells you everything you need to know (because you add that telemetry for exactly that reason), and if its an unfixable problem all the cameras do is give you a photo of the unfixable problem. They don't do anything to actually help you solve it.Nothing guarantees everything.No need for sarcasm, and it's a false dichotomy - pointing out a design shortfall doesn't mean the designers are inept.
The false dichotomy is stating that there is a design shortfall.
Having cameras doesn't guarantee anything.
But deployment mechanisms are always high risk, floppy ones even more so, and a generic analysis/debug tool such as a camera has value.
The trade against complexity/cost etc is a real thing, but with every year, it's trending in only one direction...
No number of close-up high-res images from multiple angles would have aided in Galileo's stuck antenna, or Akatsuki's engines, or Mariner 3's fairing, or PROCYON's engine issue, or etc.
Post by: deadman1204 on 10/21/2021 04:32 pm
There are infinite locations and scenarios where a camera/sensor might be useful. Obviously we can't double the payload with "what if" sensors. So how do you get around this?
Post by: meekGee on 10/21/2021 04:37 pm
And the problem, as multiple people have already stated, is that an image of the failure is not of much - if any - actual help. If it's a fixable problem the telemetry already tells you everything you need to know (because you add that telemetry for exactly that reason), and if its an unfixable problem all the cameras do is give you a photo of the unfixable problem. They don't do anything to actually help you solve it.Nothing guarantees everything.No need for sarcasm, and it's a false dichotomy - pointing out a design shortfall doesn't mean the designers are inept.
The false dichotomy is stating that there is a design shortfall.
Having cameras doesn't guarantee anything.
But deployment mechanisms are always high risk, floppy ones even more so, and a generic analysis/debug tool such as a camera has value.
The trade against complexity/cost etc is a real thing, but with every year, it's trending in only one direction...
No number of close-up high-res images from multiple angles would have aided in Galileo's stuck antenna, or Akatsuki's engines, or Mariner 3's fairing, or PROCYON's engine issue, or etc.
That's just not true.
Knowing the nature of the fault (if it's in the flexible membrane), which the encoders certainly don't yell you, is very likely what's going to help you develop a fix or a work around.
There are situations where all the camera will give you is a useless picture of a broken system, but same goes for other sensors.
Meanwhile the cost of designing in cameras keep dropping, resolution keep increasing.
Post by: meekGee on 10/21/2021 05:09 pm
Question for all those dead sweet on extra cameras. Think about this. You want a camera to look at any part that malfunctions at any point. How many is that? Hundreds? What if they wanna see solar panel problem in 6 years? So now they all gotta lay the length of the mission.That's death by over-speccing...
There are infinite locations and scenarios where a camera/sensor might be useful. Obviously we can't double the payload with "what if" sensors. So how do you get around this?
I want 1-2 cameras to see the deployment sequence, holistically.
They don't have to see the latches work, they need to see how the fabric is unfurling.
So something that will show if for example some harness got knocked loose and is snagging. Because that will inform the mission controllers how to try to unsnag it.
Don't need crazy resolution either, and it's most important to watch during deploy since that's the high risk portion.
Post by: zubenelgenubi on 10/21/2021 05:13 pm
ONE
Re: "here-a-camera, there-a-camera, everywhere-an-engineering-camera" discussion.
We're no longer learning anything.
Stop, until we have some new information.
TWO, to fast in this instance, but applicable in general:
Ad hominem attacks are a logical fallacy, whether intended for an individual or a collection of individuals.
I read back into your post history and I find ad hominem attacks. Stop.
Also, a thread trim.
Edit: And another thread trim after my warning was ignored.
2nd edit: And yet another thread trim after fast ignored my warning.
Post by: AstroWare on 10/22/2021 02:48 pm
https://youtu.be/bnDeJ7saLQY
Sent from my Pixel 5a using Tapatalk
Post by: Rondaz on 10/22/2021 08:48 pm
Karen Fox Posted on October 22, 2021
NASA’s Lucy spacecraft successfully transitioned to cruise mode Oct. 20, which is the standard configuration for flight. The following day, the instrument pointing platform was deployed after temporarily being postponed earlier in the week. Both events were normal and raised no concerns. The spacecraft remains stable, power positive, with all other subsystems working, with the exception of one solar array.
The Lucy team is working to understand the current state of the array before attempting to complete deployment. NASA is reviewing spacecraft data, including using techniques to measure how much electric current is produced by the array during various spacecraft positions and attitudes. This will allow the team to understand how close the array is to the latched position. These techniques are well within the capabilities of the system and pose no risk. Any plans for re-deployment will be considered after completing this latest assessment.
The spacecraft continues to travel along its expected trajectory –track its path online.
https://blogs.nasa.gov/lucy/2021/10/22/lucy-spacecraft-healthy-as-nasa-continues-solar-array-assessments/
Post by: Dr.Imtiyaz on 10/23/2021 02:18 pm
Post by: zubenelgenubi on 10/23/2021 08:35 pm
Thread trim. Again.
Moderator:
ONE
Re: "here-a-camera, there-a-camera, everywhere-an-engineering-camera" discussion.
We're no longer learning anything.
Stop, until we have some new information.
Post by: Targeteer on 10/24/2021 06:00 am
Lucy Spacecraft Healthy as NASA Continues Solar Array Assessments
Karen Fox Posted on October 22, 2021
NASA’s Lucy spacecraft successfully transitioned to cruise mode Oct. 20, which is the standard configuration for flight. The following day, the instrument pointing platform was deployed after temporarily being postponed earlier in the week. Both events were normal and raised no concerns. The spacecraft remains stable, power positive, with all other subsystems working, with the exception of one solar array.
The Lucy team is working to understand the current state of the array before attempting to complete deployment. NASA is reviewing spacecraft data, including using techniques to measure how much electric current is produced by the array during various spacecraft positions and attitudes. This will allow the team to understand how close the array is to the latched position. These techniques are well within the capabilities of the system and pose no risk. Any plans for re-deployment will be considered after completing this latest assessment.
The spacecraft continues to travel along its expected trajectory –track its path online.
https://blogs.nasa.gov/lucy/2021/10/22/lucy-spacecraft-healthy-as-nasa-continues-solar-array-assessments/
"Any plans for re-deployment will be considered after completing this latest assessment..." seems to indicate the deployment is motor driven. Can someone confirm?
Post by: woods170 on 10/24/2021 09:29 am
Lucy Spacecraft Healthy as NASA Continues Solar Array Assessments
Karen Fox Posted on October 22, 2021
NASA’s Lucy spacecraft successfully transitioned to cruise mode Oct. 20, which is the standard configuration for flight. The following day, the instrument pointing platform was deployed after temporarily being postponed earlier in the week. Both events were normal and raised no concerns. The spacecraft remains stable, power positive, with all other subsystems working, with the exception of one solar array.
The Lucy team is working to understand the current state of the array before attempting to complete deployment. NASA is reviewing spacecraft data, including using techniques to measure how much electric current is produced by the array during various spacecraft positions and attitudes. This will allow the team to understand how close the array is to the latched position. These techniques are well within the capabilities of the system and pose no risk. Any plans for re-deployment will be considered after completing this latest assessment.
The spacecraft continues to travel along its expected trajectory –track its path online.
https://blogs.nasa.gov/lucy/2021/10/22/lucy-spacecraft-healthy-as-nasa-continues-solar-array-assessments/ (https://blogs.nasa.gov/lucy/2021/10/22/lucy-spacecraft-healthy-as-nasa-continues-solar-array-assessments/)
"Any plans for re-deployment will be considered after completing this latest assessment..." seems to indicate the deployment is motor driven. Can someone confirm?
Deployment is motor driven. An electrical motor is used to reel in a lanyard that's wrapped around end plates of the of the ultraflex array.
The current thinking at NG and NASA is that reeling in the lanyard stopped prematurely upon deployment, leaving the array only partially unfolded and unlatched. Commanding the deployment sequence again would once again see the electric motor start reeling in the lanyard, maybe this timing completing the job and pulling the end plates into each other for latching.
More on how Ultraflex arrays work:
- https://www.jpl.nasa.gov/nmp/st8/tech_papers/2005%20IEEE%20Aerospace%20Conference%20_Big%20Sky_%20Paper-%20NGU%20ST8.pdf (https://www.jpl.nasa.gov/nmp/st8/tech_papers/2005%20IEEE%20Aerospace%20Conference%20_Big%20Sky_%20Paper-%20NGU%20ST8.pdf)
- https://www.eng.auburn.edu/~dbeale/ESMDCourse/Site%20Documents/Ultraflex%20Solar%20Array.pdf (https://www.eng.auburn.edu/~dbeale/ESMDCourse/Site%20Documents/Ultraflex%20Solar%20Array.pdf)
- https://core.ac.uk/download/pdf/42791671.pdf (https://core.ac.uk/download/pdf/42791671.pdf)
Post by: fast on 10/25/2021 06:53 am
This is obviously not Lucy, but I thought it was interesting to see a video of an ultraflex array being deployed in space (vs. The ground testing that has been shown for Lucy so far). Unfortunately the video seems to have missed the initial half of the sequence.
https://youtu.be/bnDeJ7saLQY
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There quite violent event at 0.15 sec.
Post by: AstroWare on 10/25/2021 02:23 pm
I don't think it is playing at actual speed. The title says "3FPS" but the video speed looks like 10fps per the stats for nerds overlay.This is obviously not Lucy, but I thought it was interesting to see a video of an ultraflex array being deployed in space (vs. The ground testing that has been shown for Lucy so far). Unfortunately the video seems to have missed the initial half of the sequence.
https://youtu.be/bnDeJ7saLQY
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There quite violent event at 0.15 sec.
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Post by: AstroWare on 10/25/2021 02:42 pm
Cool material. I wasn't aware that these arrays had been around so long. I didn't see in the documents anywhere that said what determined the lanyard retraction was complete.Lucy Spacecraft Healthy as NASA Continues Solar Array Assessments
Karen Fox Posted on October 22, 2021
NASA’s Lucy spacecraft successfully transitioned to cruise mode Oct. 20, which is the standard configuration for flight. The following day, the instrument pointing platform was deployed after temporarily being postponed earlier in the week. Both events were normal and raised no concerns. The spacecraft remains stable, power positive, with all other subsystems working, with the exception of one solar array.
The Lucy team is working to understand the current state of the array before attempting to complete deployment. NASA is reviewing spacecraft data, including using techniques to measure how much electric current is produced by the array during various spacecraft positions and attitudes. This will allow the team to understand how close the array is to the latched position. These techniques are well within the capabilities of the system and pose no risk. Any plans for re-deployment will be considered after completing this latest assessment.
The spacecraft continues to travel along its expected trajectory –track its path online.
https://blogs.nasa.gov/lucy/2021/10/22/lucy-spacecraft-healthy-as-nasa-continues-solar-array-assessments/ (https://blogs.nasa.gov/lucy/2021/10/22/lucy-spacecraft-healthy-as-nasa-continues-solar-array-assessments/)
"Any plans for re-deployment will be considered after completing this latest assessment..." seems to indicate the deployment is motor driven. Can someone confirm?
Deployment is motor driven. An electrical motor is used to reel in a lanyard that's wrapped around end plates of the of the ultraflex array.
The current thinking at NG and NASA is that reeling in the lanyard stopped prematurely upon deployment, leaving the array only partially unfolded and unlatched. Commanding the deployment sequence again would once again see the electric motor start reeling in the lanyard, maybe this timing completing the job and pulling the end plates into each other for latching.
More on how Ultraflex arrays work:
- https://www.jpl.nasa.gov/nmp/st8/tech_papers/2005%20IEEE%20Aerospace%20Conference%20_Big%20Sky_%20Paper-%20NGU%20ST8.pdf (https://www.jpl.nasa.gov/nmp/st8/tech_papers/2005%20IEEE%20Aerospace%20Conference%20_Big%20Sky_%20Paper-%20NGU%20ST8.pdf)
- https://www.eng.auburn.edu/~dbeale/ESMDCourse/Site%20Documents/Ultraflex%20Solar%20Array.pdf (https://www.eng.auburn.edu/~dbeale/ESMDCourse/Site%20Documents/Ultraflex%20Solar%20Array.pdf)
- https://core.ac.uk/download/pdf/42791671.pdf (https://core.ac.uk/download/pdf/42791671.pdf)
Timer? Motor encoder (revolutions)? Contact switch?
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Post by: joncz on 10/25/2021 03:26 pm
Cool material. I wasn't aware that these arrays had been around so long. I didn't see in the documents anywhere that said what determined the lanyard retraction was complete.
Timer? Motor encoder (revolutions)? Contact switch?
{Edit: I'm not saying this is the case on Lucy; am presenting an analogue on another system}.
I've seen in the past (can't recall where at the moment) where it's current to the motor used to determine completion. Once the lanyard goes taut, the load on the motor, and consequently its current draw, increases. Stiction can cause a false reading, and once confirmed, that threshold can be increased and the retraction tried again.
Post by: mmonty on 10/25/2021 05:31 pm
I didn't see in the documents anywhere that said what determined the lanyard retraction was complete.Timer
Timer? Motor encoder (revolutions)? Contact switch?
Post by: Rondaz on 10/28/2021 03:00 am
Karen Fox Posted on October 27, 2021
The Lucy spacecraft remains in cruise mode, which is the standard flight mode for outbound flight and allows for substantial autonomy for the spacecraft. The spacecraft has successfully executed several small planned maneuvers, which have had no adverse effect on the one solar array that is not fully deployed. On Oct. 29, NASA will adjust Lucy’s position to point toward Earth in preparation for instrument checkout.
Most recently, the spacecraft’s position was adjusted on Oct. 26 to allow the team to measure how much electric current is moving through the partially deployed solar array and thus understand how close that array is to the fully latched position. Analysis indicates that the array is between 75% and 95% deployed. It is currently being held in place by a lanyard, specifically designed to help unfurl the arrays during deployment.
An anomaly response team continues to work on establishing what caused the solar array to not fully deploy. NASA and SwRI are evaluating a range of options, including the possibility of leaving the array in its current state. Any attempt to safely redeploy the array would occur no earlier than Nov. 16.
https://blogs.nasa.gov/lucy/2021/10/27/lucy-stable-in-cruise-mode/
Post by: eeergo on 10/28/2021 09:54 am
They certainly would help in this situation. Doubt they have a set of diagnostic sensors that gives them an accurate, complete overview of what the array looks like at this time, or what it will look like after troubleshooting attempts, thruster firings or other maneuvers
Yes they do. The power output is proportional to amount of deployment.
A camera would unlikely see the latching mechanism.
Power output will be sinusoidally-dependent on the inclination of the cells with respect to the Sun vector - it won't be too sensitive when deployment is near-complete (say, between 325 and 360 degrees of deployment boom rotation). Also, you'll be assuming that the folding of the array is still unaltered from the nominal pattern, which may not be the case if it deployed completely, failed to latch, and went back - or if something more radical happened to the array, such as tears or snags.
Indeed this uncertainty appears to be driving the diagnosis:
https://twitter.com/NASASolarSystem/status/1453466401063247877
Note this analysis could have been done in a split second with an image, while discovering short-term variations if any.
Post by: edzieba on 10/28/2021 11:55 am
Note this analysis could have been done in a split second with an image, while discovering short-term variations if any.Assuming the problem is visible in an image. As we can see with the Cygnus deployment camera view posted upthread, the entire array is not in view, and other portions of the deployment system would not be visible with cameras attached to the spacecraft body (e.g. viewing the latching area to watch for deployment lanyard wear/snags/tangling/etc).
But this is circling back round to unproductive territory. Lucy's array is currently stable, and "no further action needed" is one of the options under consideration. I expect much of the work currently being undergone is modelling dynamics of the unlatched array to determine the impacts on manoeuvrability of an unlatched array, rather than pondering on the current state of the array.
Post by: Jim on 10/28/2021 02:40 pm
There quite violent event at 0.15 sec.
That isn't violent, but typical.
Post by: Blackstar on 10/28/2021 03:45 pm
Post by: Rondaz on 11/05/2021 08:03 pm
Karen Fox Posted on November 5, 2021
The Lucy spacecraft continues to operate in cruise mode – the standard mode for outbound orbit. The team has begun turning on instruments. L’TES and L’Ralph have been powered on and are working normally. Turning on L’LORRI is scheduled for Nov. 8, 2021. Other than the solar array, all subsystems continue to work normally.
The joint Anomaly Response Team has been studying the array using an engineering model. Initial tests indicate that the lanyard that pulls out the solar array may not have completed the process successfully; however, it is still uncertain what caused this condition. The team is conducting more tests to determine if this is indeed the case, and what the root cause might be.
An attempt to characterize the array deployment by attempting to move it would occur no earlier than Nov. 16.
The response team continues its analysis on using the solar array in its current configuration and how that might affect upcoming spacecraft maneuvers.
https://blogs.nasa.gov/lucy/2021/11/05/nasas-lucy-instruments-being-turned-on-and-working-normally/
Post by: LouScheffer on 11/06/2021 02:08 am
Post by: AstroWare on 11/06/2021 05:06 am
Do any other missions use similar arrays? If so they presumably will be on hold until a root cause, and fix, for this problem is found.Cygnus obviously does. These were the first flight of this SIZE array, so it depends on if they feel it's related to all arrays or just this unique version.
NG-17 is up next, Spring 2022
(Just spitballing here, but I'm wondering if Cygnus could be used as a possible troubleshooting instrument. NG-17 could be uniquely instrumented to gather deployment data. After leaving the ISS, arrays could be commanded to pulse the motors to make sure that works as expected. Also could be done on the ISS, as The ISS may have ways to monitor with cameras. Lucy has time it seems, may be worth considering.)
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Post by: Phil Stooke on 11/06/2021 05:38 am
Post by: LouScheffer on 11/06/2021 11:35 am
Do any other missions use similar arrays? If so they presumably will be on hold until a root cause, and fix, for this problem is found.In addition to Cygnus, Insight and Phoenix also used these folding circular arrays, but those are already launched (and deployed successfully)
So the question is, are they willing to launch Cygnus with a poorly understood failure in the same family of solar arrays? I'd guess not, so this puts some pressure on the Lucy team to debug the problem. They may not need to actually unfold the array, but at least they will need to understand the cause so that the Cygnus team can avoid a repeat.
This brings up the forbidden topic, cameras. Lucy has lots of telemetry, and it may be enough, but it's not fast. Typically debugging a stuck deployment using existing sensors requires lots of spacecraft maneuvering. They may orient the spacecraft to heat/cool various components, change the insolation, wiggle the spacecraft and measure the response, turn the spacecraft so that existing telemetry (such as a sun sensor) can be used, and so on. Lucy has already spent three weeks doing these tests, so far. Cygnus would not have time to do these tests before rendezvous, and could not do them once berthed. In this case I feed certain that NASA would take pictures, and if needed even send an astronaut to investigate in person (via EVA) if the pictures were not conclusive.
[...] an image of the failure is not of much - if any - actual help. [...] if its an unfixable problem all the cameras do is give you a photo of the unfixable problem. They don't do anything to actually help you solve it.Only true in isolation. They may not help your mission solve it, but they can help the next mission avoid it. That's why NASA started demanding telemetry during descent of Mars missions. In case of mishap it is no help to the mission, but it could help later ones avoid the same fate.
Post by: Jim on 11/06/2021 01:22 pm
1. So the question is, are they willing to launch Cygnus with a poorly understood failure in the same family of solar arrays?
2. I'd guess not, so this puts some pressure on the Lucy team to debug the problem. They may not need to actually unfold the array, but at least they will need to understand the cause so that the Cygnus team can avoid a repeat
1. It's up to NG. But most likely they will.
2. It doesn't nothing of the sort. The spacecraft teams, missions, risk structure, etc are all separate. Lucy owes nothing to Cygnus. NG, the manufacturer of the solar arrays for both, is already involved.
Post by: Jim on 11/06/2021 01:27 pm
Only true in isolation. They may not help your mission solve it, but they can help the next mission avoid it. That's why NASA started demanding telemetry during descent of Mars missions. In case of mishap it is no help to the mission, but it could help later ones avoid the same fate.
Not the same thing. It is telemetry. Cameras would also be useless without telemetry.
Post by: TrevorMonty on 11/06/2021 03:17 pm
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Post by: webdan on 11/06/2021 03:31 pm
From October 27, 2021:
Quote
Most recently, the spacecraft’s position was adjusted on Oct. 26 to allow the team to measure how much electric current is moving through the partially deployed solar array and thus understand how close that array is to the fully latched position. Analysis indicates that the array is between 75% and 95% deployed. It is currently being held in place by a lanyard, specifically designed to help unfurl the arrays during deployment.
Edit: Updated link points to relevant entries.
Post by: LouScheffer on 11/07/2021 10:29 pm
I sincerely hope this not the attitude at NASA. Both ISS re-supply and planetary exploration are NASA objectives. For Lucy to say "not my problem" when something they could do would help a sister project would be the mark of a dysfunctional organization. If the resolution of the Lucy failure would help maintain the ISS schedule, I'd expect the NASA administrator (to whom they both ultimately report) to direct Lucy to work harder than they might if it was only their problem.It doesn't nothing of the sort. The spacecraft teams, missions, risk structure, etc are all separate. Lucy owes nothing to Cygnus. NG, the manufacturer of the solar arrays for both, is already involved.
[...] this puts some pressure on the Lucy team to debug the problem. They may not need to actually unfold the array, but at least they will need to understand the cause so that the Cygnus team can avoid a repeat
Post by: Jim on 11/08/2021 01:02 am
I sincerely hope this not the attitude at NASA. Both ISS re-supply and planetary exploration are NASA objectives. For Lucy to say "not my problem" when something they could do would help a sister project would be the mark of a dysfunctional organization. If the resolution of the Lucy failure would help maintain the ISS schedule, I'd expect the NASA administrator (to whom they both ultimately report) to direct Lucy to work harder than they might if it was only their problem.
wrong again on every point.
It is not a NASA sister project. Cygnus is a commercial project of NG and not NASA. NASA is only buying a service from NG. NG manages the hardware and risks.
Lucy has a different risk posture and goals and is not going to jeopardize anything for Cygnus.
Post by: Sam Ho on 11/08/2021 04:05 am
Some years ago Orion was rendered with circular solar arrays, e.g. some of the dual Orion scenarios visiting a small asteroid. Now, of course, it's four rectangular arrays.The US-built Orion service module would have used the Ultraflex arrays. The current European-built one does not.
Lucy's Ultraflex arrays are 7.3m diameter. The Cygnus ones are 3.7m, and Phoenix and Insight are about 2.1m. The Orion ones would have been 6m.
The post below has an Ultraflex brochure from 2015 attached. (The source link is dead now, as Orbital ATK has since been absorbed by NG.)
For an overview of the stuff that is well-proven today, here's a brochure for Orbital-ATK's Ultraflex panels, which have flown successfully on the Phoenix Mars lander and which will be used on the next Cygnus flight:(also attached) https://www.orbitalatk.com/space-systems/space-components/solar-arrays/docs/FS007_15_OA_3862%20UltraFlex.pdf
Note that these are arrays designed to survive a high-vibration launch environment, deploy, and then survive 1-5 gees and/or martian dust storms when deployed. Less overengineered mechanical supports could achieve significantly higher power to weight ratios, especially if assembled in space.
Post by: DanClemmensen on 11/08/2021 04:34 am
Earliest capture of the page at Internet Archive is:Some years ago Orion was rendered with circular solar arrays, e.g. some of the dual Orion scenarios visiting a small asteroid. Now, of course, it's four rectangular arrays.The US-built Orion service module would have used the Ultraflex arrays. The current European-built one does not.
Lucy's Ultraflex arrays are 7.3m diameter. The Cygnus ones are 3.7m, and Phoenix and Insight are about 2.1m. The Orion ones would have been 6m.
The post below has an Ultraflex brochure from 2015 attached. (The source link is dead now, as Orbital ATK has since been absorbed by NG.)For an overview of the stuff that is well-proven today, here's a brochure for Orbital-ATK's Ultraflex panels, which have flown successfully on the Phoenix Mars lander and which will be used on the next Cygnus flight:(also attached) https://www.orbitalatk.com/space-systems/space-components/solar-arrays/docs/FS007_15_OA_3862%20UltraFlex.pdf
Note that these are arrays designed to survive a high-vibration launch environment, deploy, and then survive 1-5 gees and/or martian dust storms when deployed. Less overengineered mechanical supports could achieve significantly higher power to weight ratios, especially if assembled in space.
https://web.archive.org/web/20150614210218/https://www.orbitalatk.com/space-systems/space-components/solar-arrays/docs/FS007_15_OA_3862%20UltraFlex.pdf
Post by: LouScheffer on 11/08/2021 12:00 pm
You're kidding, right? If at the Cygnus Launch Readiness Review, NASA says "We are not comfortable launching with a not-understood in-family failure, and won't sign off until it a root cause is determined and mitigated", then NG could launch anyway?I sincerely hope this not the attitude at NASA. Both ISS re-supply and planetary exploration are NASA objectives. For Lucy to say "not my problem" when something they could do would help a sister project would be the mark of a dysfunctional organization. If the resolution of the Lucy failure would help maintain the ISS schedule, I'd expect the NASA administrator (to whom they both ultimately report) to direct Lucy to work harder than they might if it was only their problem.It is not a NASA sister project. Cygnus is a commercial project of NG and not NASA. NASA is only buying a service from NG. NG manages the hardware and risks.
And NASA even more directly controls the Lucy mission. I agree NASA will not force Lucy to do anything that might jeopardize the mission, but they can surely direct them to expedite the process.
Post by: Jim on 11/08/2021 12:09 pm
You're kidding, right? If at the Cygnus Launch Readiness Review, NASA says "We are not comfortable launching with a not-understood in-family failure, and won't sign off until it a root cause is determined and mitigated", then NG could launch anyway?
Nope. Not NASA's call to make.
The LRR is not a NASA review, it is NG review and NASA is only an observer for most of it. NASA's only call is on ops near the ISS. NASA has a separate review for ISS ops (ORR).
Post by: Jim on 11/08/2021 12:14 pm
And NASA even more directly controls the Lucy mission. I agree NASA will not force Lucy to do anything that might jeopardize the mission, but they can surely direct them to expedite the process.
No, not really. ISS (JSC) NASA isn't going to tell SMD (GSFC) NASA to change or speed up their plans for Cygnus. Especially, when troubleshooting involves maneuvering by Lucy.
ISS logstics is much lower level priority than science spacecraft
Post by: Rondaz on 11/10/2021 08:06 pm
21:30 10 Nov 2021
The interplanetary station "Lucy" sent the first photo from space, which was the final stage of the initial check of all subsystems of the apparatus after launch. The device still has not fully revealed one of the solar panels, it is expected that an attempt to fully deploy it will take place no earlier than November 16, according to the blog of the mission.
Lucy was launched into space on October 16, 2021, its purpose is to study seven Trojan asteroids of Jupiter, which are located in the vicinity of the L 4 and L 5 Lagrange points in the Sun-Jupiter system, and one Main Belt asteroid. The study of such objects will help planetary scientists better understand the processes that took place in the early solar system. The station will study all asteroids from a flyby using four scientific instruments - two cameras and two spectrometers.
A distinctive feature of the station are two deployable circular solar panels, each 7.3 meters in diameter. A day after the launch of the spacecraft, NASA reported that one of the batteries might not fully open. Further analysis of the data from the station showed that the degree of disclosure of the battery is from 75 to 95 percent. It is not fixed, but it maintains its position with a sling and generates almost the same level of electricity as a fully expanded battery. The engineering team is expected to try to redeploy the battery on November 16. If this does not help, then the battery may be left in this state for the entire duration of the flight.
On November 9, the Lucy team published the first photograph taken by the station. The picture was taken with a T2Cam and shows the starry sky. At the moment, all scientific instruments of the apparatus have passed preliminary tests, and the station is in flight mode. The first trajectory correction maneuver is expected to take place in mid-December.
We talked in detail about the scientific program "Lucy" in the material "Flying around Troy" .
Alexander Voytyuk
https://nplus1.ru/news/2021/11/10/lucy-first-photo
Post by: Jim on 11/10/2021 08:10 pm
Alexander Voytyuk
https://nplus1.ru/news/2021/11/10/lucy-first-photo
Is he just repeating a NASA press release?
Post by: John Santos on 11/10/2021 09:02 pm
Post by: ccdengr on 11/10/2021 09:06 pm
Is he just repeating a NASA press release?Couldn't find a press release, but some of this info is from the Lucy twitter feed: https://twitter.com/LucyMission
Post by: deadman1204 on 11/10/2021 09:18 pm
13 Enhanced Cygnus craft have flown with the OTK solar arrays, with out any problems (Cygnus OA-4 to NG-16), as have Insight and Phoenix (and possibly others?), adding up to at least 32 arrays, including Lucy. There has been only one deployment failure, which has not resulted in loss-of-mission. This is a 3% partial failure rate. NASA/NG could engage in analysis paralysis trying to diagnose the issue, or they could just inspect all the unflown arrays for any signs of damage or possible problems, review the test data from the development of the arrays (both of which they have probably already done, or at least commenced), and launch the next Cygnus, knowing full well that if there is an issue, they can actually look at it up close and personal, and maybe poke it with a stick. The worst outcome might be a power shortage on the Cygus that would affect the environment of any cargo. (If there was anything incredibly valuable on board, they could replace it with food, water, clothing or other nonperishible cargo and launch the vulnerable stuff next time.) That's almost never possible with space hardware, but it is possible with Cygnus and it makes perfect sense to me.
Soo a few things:
1. There are no cyngus arrays to inspect because they all burn up on reentry
2. Its a completely different system. Lucy's panels are specially made for this mission. Thats like saying all buildings are the same cause they all have the same vague shape.
3. If they break something, they are screwed. Its gonna take years for lucy to get anywhere. Who cares if they are careful and take a few weeks/months to figure it out. If they rush and mess up, there is no undo button.
Post by: mn on 11/10/2021 09:31 pm
...
2. Its a completely different system. Lucy's panels are specially made for this mission. Thats like saying all buildings are the same cause they all have the same vague shape.
..
It has been stated many times on this thread (and therefore it must be true ;)), that it is the same array as cygnus just larger.
Did NG change anything just for Lucy (likely, considering the larger size)?
Or perhaps they changed something recently that is applicable to Lucy and also Cygnus?
Post by: deadman1204 on 11/10/2021 11:16 pm
...
2. Its a completely different system. Lucy's panels are specially made for this mission. Thats like saying all buildings are the same cause they all have the same vague shape.
..
It has been stated many times on this thread (and therefore it must be true ;)), that it is the same array as cygnus just larger.
Did NG change anything just for Lucy (likely, considering the larger size)?
Or perhaps they changed something recently that is applicable to Lucy and also Cygnus?
And yet, the big question no one can answer - whats the rush?
Post by: LouScheffer on 11/12/2021 01:29 pm
There is no rush for Lucy - they have years of cruise to get this system sorted out.It has been stated many times on this thread (and therefore it must be true ;)), that it is the same array as cygnus just larger.
Did NG change anything just for Lucy (likely, considering the larger size)?
Or perhaps they changed something recently that is applicable to Lucy and also Cygnus?
And yet, the big question no one can answer - whats the rush?
However, there is a Cyngus launch, NG-17, scheduled for February 2022, about 4 months from now. The arrays on that mission use a closely related deployment technology. NASA is paying about $262 million for each Cygnus flight (https://arstechnica.com/science/2018/04/nasa-to-pay-more-for-less-cargo-delivery-to-the-space-station/) and might reasonably be concerned about launching with a system that has an un-understood failure in a closely related product. This concern could be addressed if Lucy finds a root cause for the deployment failure. Lucy does not need to fix the problem by this deadline, just understand what caused it so Cygnus can rule out a similar failure.
Members here disagree on the seriousness of this deadline. Jim believes that NG could decide to launch Cygnus without first understanding the cause of the Lucy failure to deploy, and that NASA would/could not force this issue. I, on the other hand, believe that NASA is paying for the mission, and is historically very averse to launching with potential problems un-resolved. (Certainly for commercial crew, NASA has demanded all sorts of work by the providers to make sure every failure mode was understood as well as possible. Perhaps they would be more tolerant of risk for ISS resupply - it's "only" $262 million, after all - but I find this hard to believe.)
And perhaps the Lucy problem, though not fully understood, is understood well enough to know the same flaw will not happen on Cygnus. There has been no public indication of this, but if so there is no urgency to finding the true root cause.
Post by: Jim on 11/12/2021 02:07 pm
Perhaps they would be more tolerant of risk for ISS resupply - it's "only" $262 million, after all - but I find this hard to believe.)
They are because it isn't $262 million until the cargo is delivered. CRS does have a different risk posture. Believe it.
Post by: deadman1204 on 11/12/2021 02:08 pm
There is no rush for Lucy - they have years of cruise to get this system sorted out.It has been stated many times on this thread (and therefore it must be true ;)), that it is the same array as cygnus just larger.
Did NG change anything just for Lucy (likely, considering the larger size)?
Or perhaps they changed something recently that is applicable to Lucy and also Cygnus?
And yet, the big question no one can answer - whats the rush?
However, there is a Cyngus launch, NG-17, scheduled for February 2022, about 4 months from now. The arrays on that mission use a closely related deployment technology. NASA is paying about $262 million for each Cygnus flight (https://arstechnica.com/science/2018/04/nasa-to-pay-more-for-less-cargo-delivery-to-the-space-station/) and might reasonably be concerned about launching with a system that has an un-understood failure in a closely related product. This concern could be addressed if Lucy finds a root cause for the deployment failure. Lucy does not need to fix the problem by this deadline, just understand what caused it so Cygnus can rule out a similar failure.
Members here disagree on the seriousness of this deadline. Jim believes that NG could decide to launch Cygnus without first understanding the cause of the Lucy failure to deploy, and that NASA would/could not force this issue. I, on the other hand, believe that NASA is paying for the mission, and is historically very averse to launching with potential problems un-resolved. (Certainly for commercial crew, NASA has demanded all sorts of work by the providers to make sure every failure mode was understood as well as possible. Perhaps they would be more tolerant of risk for ISS resupply - it's "only" $262 million, after all - but I find this hard to believe.)
And perhaps the Lucy problem, though not fully understood, is understood well enough to know the same flaw will not happen on Cygnus. There has been no public indication of this, but if so there is no urgency to finding the true root cause.
Do we actually know they are the same system, only different sized? Even if Cygnus made them both, that doesn't automatically mean they function identically.
Post by: LouScheffer on 11/12/2021 02:43 pm
Last time Cygnus failed, NASA paid 80% of the full price, plus had to replace all the cargo, and there was no requirement for OA to replace the missing upmass. From the Inspector general's report (https://oig.nasa.gov/docs/IG-15-023.pdf):Perhaps they would be more tolerant of risk for ISS resupply - it's "only" $262 million, after all - but I find this hard to believe.)They are because it isn't $262 million until the cargo is delivered. CRS does have a different risk posture. Believe it.
Quote
[..] the CRS-1 contracts do not require Orbital or SpaceX to re-fly failed missions or carry upmass from a failed mission on future flights, nor do they make the companies liable for any cargo destroyed as a result of a launch failure or other anomaly. While Orbital or SpaceX would forfeit the cargo delivery milestone payment (20 percent) as a penalty for a mission failure, NASA is not entitled to recover milestone payments already made for a failed launch [...]That would seem to supply plenty of incentive for NASA to care about this problem, even if it's NG's direct responsibility. Plus, of course, the impact on ISS logistics.
Anyway this thread is about Lucy. I hope they will find the cause in time, and this whole question will be moot.
Post by: Jim on 11/12/2021 03:00 pm
Post by: woods170 on 11/13/2021 03:21 pm
<snip>
Do we actually know they are the same system, only different sized? Even if Cygnus made them both, that doesn't automatically mean they function identically.
Emphasis mine.
Yes, same basic system. One of the regularly advertised strong points of the Ultraflex arrays is the scalability.
The arrays on Cygnus, Lucy and the lander at the Martian pole all use the same basic design, same basic structure (albeit scaled) and same materials. Solar Cells might be different though, depending on such factors as required resistance to radiation, etc.
Post by: TrevorMonty on 11/13/2021 04:58 pm
Sent from my SM-G570Y using Tapatalk
Post by: edzieba on 11/29/2021 01:56 pm
Quote
NASA’s Lucy spacecraft continues to operate in cruise mode – the standard mode for its orbit away from Earth.
Checkouts for the Lucy instruments were successfully completed Nov. 8, and all instruments are working normally
. Following checkout completion, the instruments were powered off, and the remaining spacecraft subsystem commissioning activities are continuing as scheduled.
Lucy’s Solar Array Anomaly Response Team has made progress searching for the cause of the solar array’s incomplete deployment. The team has used an engineering model of the solar array motor and lanyard to replicate what was observed during the initial solar array deployment. The test data and findings suggest the lanyard may not have wound on the spool as intended. Testing continues to determine what caused this outcome, and a range of scenarios are possible. The team isn’t planning to attempt to move or further characterize the current state of the solar array deployment before Wednesday, Dec. 1, at the earliest.
Post by: Rondaz on 12/08/2021 05:44 pm
Karen Fox Posted on December 8, 2021
NASA plans to conduct additional ground tests on an engineering model of the solar array motor and lanyard prior to potentially attempting full deployment of one of the probe’s solar arrays.
A project team completed an assessment Dec. 1 of the ongoing solar array issue, which did not appear to fully deploy as planned after launch in late October. Initial ground tests determined additional motor operations are required to increase the probability of the latching Lucy’s array in place as intended, and the team has recommended additional testing.
Spacecraft operations included discharging and charging the battery while pointed at Earth, moving the spacecraft to point to the Sun, operating the solar array motor with the launch day parameters, moving back to pointing at Earth, and then another battery discharge and recharge. The solar arrays charge the batteries, then the batteries are deliberately discharged, and the solar array circuits are used to recharge the batteries; performing these charging and discharging processes gives the team more information about the solar array circuits.
The team gathered information on two of the 10 gores – the individual solar array panel segments that make up the full array — that previously had no data. NASA now has data on all 10 gores confirming they are open, producing power as expected, and not stuck together.
These activities are helping the agency create a robust plan for attempting to fully deploy the array. Additional ground tests using the engineering model setup will validate a two-motor attempt for full deployment. NASA currently is creating a schedule and the resources needed to support that effort, as well as continuing to study the possibility of leaving the array as is.
https://blogs.nasa.gov/lucy/2021/12/08/nasa-zeroing-in-on-path-forward-for-lucy-solar-array/
Post by: Rondaz on 12/09/2021 09:47 am
https://twitter.com/nextspaceflight/status/1468842462533672960
Post by: Rondaz on 12/17/2021 02:25 pm
https://youtu.be/bytkvsQepts
Post by: Rondaz on 01/12/2022 05:47 pm
Karen Fox Posted on January 12, 2022
The Lucy spacecraft, launched on Oct. 16, 2021, is now over 30 million miles, or 48 million kilometers, from Earth and continues to operate safely in “outbound cruise” mode. Besides a solar array that didn’t latch after deployment — an issue the mission team is working to resolve— all spacecraft systems are normal. The arrays are producing ample energy, charging the spacecraft’s battery as expected under normal operating conditions.
The current plan supports a latch attempt in the late April timeframe; however, the team is continuing to study the possibility of leaving the array as is. In the meantime, in the lab, they are testing a dual motor solar array deployment using both the primary and backup motor. The testing aims to determine if engaging both motors at the same time applies enough force to complete the deployment and latch the solar array.
In addition to the solar array activity, the team continues to run routine operations on the spacecraft. The next activity is calibrating guidance, navigation & control hardware to ensure pointing accuracy of the spacecraft.
On January 5, Lucy completed a test to look at the dynamics of the spacecraft in order to characterize the solar array.
https://blogs.nasa.gov/lucy/2022/01/12/lucy-cruising-to-orbit-testing-solar-array-options-on-ground/
Post by: eeergo on 01/25/2022 06:39 pm
https://twitter.com/TM_Eubanks/status/1486050079656091653
Post by: woods170 on 01/25/2022 07:14 pm
The problem with the solar array appears to have been reliably diagnosed: the landyard used to pull the array in place somehow jumped out of its spool "lane" and started to wind around the (obviously much smaller diameter) motor shaft, causing less length of it to be wound. They appear to be able to pull harder to reel back the remaining landyard around the shaft.
https://twitter.com/TM_Eubanks/status/1486050079656091653
It will be fun to see if they manage to figure out WHY there was a period with no tension on the lanyard.
Post by: eeergo on 01/25/2022 08:49 pm
The problem with the solar array appears to have been reliably diagnosed: the landyard used to pull the array in place somehow jumped out of its spool "lane" and started to wind around the (obviously much smaller diameter) motor shaft, causing less length of it to be wound. They appear to be able to pull harder to reel back the remaining landyard around the shaft.
https://twitter.com/TM_Eubanks/status/1486050079656091653
It will be fun to see if they manage to figure out WHY there was a period with no tension on the lanyard.
I think I'm not familiar with the specifics (do you have the duration of said period at hand?) but it could be the moment the landyard "fell off" the racetrack on the spool? There must have been a moment in which the landyard was overtaut, when it was getting out of its lane and moving over the (wider diameter) ledge, and then undertaut/slack when it slipped off it, taking a certain already-spooled length of cable over with it to fall to the (narrower diameter) motor shaft, if I'm visualizing it right.
On the other hand, that proposal of a mechanism says nothing of the root cause. Was it some FOD on the racetrack the landyard spooled over and until it was eventually too thick and "fell over"? Maybe the panel swayed/stuck too much during deployment and caused a "snap" that whipped the landyard around and unwound some of it? Or was it just some design problem that popped up in 0G and made the spooling unreliable, maybe even bunching the landyard on one side of the spool? Seems unlikely they will determine such a thing with the sensors at hand...
Post by: Rondaz on 01/29/2022 09:38 pm
19:25 29 Jan. 2022
An incompletely opened one of the solar panels of the interplanetary station "Lucy" will not affect the progress of the scientific program. This was the conclusion of the mission team that analyzed the problem. Nevertheless, an attempt to re-deploy the battery will be made at the end of April, according to Spacenews.com.
Lucy was launched into space last October to study seven Jupiter Trojan asteroids and one Main Belt asteroid. Thanks to the apparatus, for the first time, scientists will see such bodies up close and will be able to test models of the processes that took place in the early solar system. The station will study all asteroids from a flyby trajectory using cameras and spectrometers.
Shortly after launch, the station deployed two circular solar arrays, each 7.3 meters in diameter. They are designed to unfold like a fan when folded. However, one of the batteries did not fully open - its end turned 347 instead of 360 degrees. As a result, the electric power generated by solar panels amounted to a little more than 90 percent of the nominal.
On January 25, 2022, Lucy Program Manager Hal Levison spoke at a meeting of the Small Body Assessment Group (SBAG) about the results of the analysis of the situation with the solar array. The cause of the problems was the loss of tension on the line pulled by the motor, which did not fully open and fix the position of the battery. However, whether the battery is fully deployed or not, the problem will not affect the progress of the science program. Engineers still have an option to try to restart the engine and re-deploy the battery at the end of April. If this operation fails, Lucy will continue to fly anyway. In mid-December, the station should make the first trajectory correction maneuver.
We talked in detail about the scientific program "Lucy" in the material "Flying around Troy" .
Alexander Voytyuk
https://nplus1.ru/news/2022/01/29/lucy-solar-array
Post by: Blackstar on 01/29/2022 10:57 pm
Ugh. This article reads like a bad translation.
Post by: Comga on 01/29/2022 11:30 pm
"an attempt to re-deploy the battery..."
Ugh. This article reads like a bad translation.
Yes
Rondaz posts news about NASA missions from Russian website. (nplus1 dot r u ) The double translation seems to do this often.
Post by: LouScheffer on 01/30/2022 12:29 pm
The problem with the solar array appears to have been reliably diagnosed: the landyard used to pull the array in place somehow jumped out of its spool "lane" and started to wind around the (obviously much smaller diameter) motor shaft, causing less length of it to be wound. They appear to be able to pull harder to reel back the remaining landyard around the shaft.As someone pointed out (perhaps in another forum), some space problems are complex faults in innovative mechanisms. This one would be immediately understood by a sailor of the fifteenth century, as would be the two possible solutions - leave it be, and keep turning the crank.
Post by: Rondaz on 04/21/2022 07:30 pm
Karen Fox Posted on April 21, 2022
On April 18, NASA decided to move forward with plans to complete the deployment of the Lucy spacecraft’s stalled, unlatched solar array. The spacecraft is powered by two large arrays of solar cells that were designed to unfold and latch into place after launch. One of the fan-like arrays opened as planned, but the other stopped just short of completing this operation.
Through a combination of rigorous in-flight solar array characterization and ground testing, Lucy engineers determined the unlatched solar array is nearly fully open, positioned at approximately 345 out of the full 360 degrees, and is producing ample energy for the spacecraft. Nonetheless, the team is concerned about potential damage to the array if the spacecraft conducts a main engine burn in its present configuration.
After launch, the arrays were opened by a small motor that reels in a lanyard attached to both ends of the folded solar array. The team estimates that 20 to 40 inches of this lanyard (out of approximately 290 inches total) remains to be retracted for the open array to latch.
The solar array was designed with both a primary and a backup motor winding to give an added layer of reliability for the mission-critical solar array deployment. Lucy engineers will take advantage of this redundancy by using both motors simultaneously to generate higher torque than was used on the day of launch. Ground tests show that this added torque may be enough to pull the snarled lanyard the remaining distance needed to latch.
The team is now preparing to complete the solar array deployment in two steps. The first step, tentatively scheduled for the week of May 9, is intended to pull in most of the remaining lanyard and verify that flight results are consistent with ground testing. This step will also strengthen the array by bringing it closer to a fully tensioned state. Because this step is designed to be limited in duration, the array is not likely to latch at that point.
If this step goes as planned, the second step will continue the array deployment with the intent to fully latch. Information gleaned from the first part will help fine-tune the second. The second step is currently planned for a month after the initial one, giving engineers enough time to analyze the data seen in the first attempt.
https://blogs.nasa.gov/lucy/2022/04/21/nasas-lucy-mission-is-go-for-solar-array-deployment-attempt/
Post by: Rondaz on 05/10/2022 04:52 pm
Erin Morton Posted on May 10, 2022
On May 9, NASA’s Lucy team executed the first of two planned steps in its efforts to complete the deployment of the spacecraft’s unlatched solar array. This first step was time-limited and was intended to validate that the team’s ground testing adequately represented the flight system’s performance, rather than to latch the solar array. Analysis is currently underway to determine if the results are consistent with ground testing. After reviewing the data, the team will determine the next steps for the deployment effort. The second step is tentatively scheduled for about a month after the first one.
https://blogs.nasa.gov/lucy/2022/05/10/nasas-lucy-team-completes-step-one-of-the-solar-array-deployment-attempt/
Post by: Rondaz on 05/20/2022 08:53 pm
https://youtu.be/2P71WZxJdyU
Post by: Barley on 05/21/2022 04:45 pm
Lucy spacecraft sees Earth & moon during lunar eclipse in amazing timelapse..What an awful way to present interesting video. Looping was entirely gratuitous.
https://youtu.be/2P71WZxJdyU
Post by: Rondaz on 05/25/2022 09:58 am
10:33 25 May 2022
The interplanetary station "Lucy" sent to Earth pictures of the beginning of a total lunar eclipse, taken from an unusual angle. During the shooting, the station was in interplanetary space and kept the Earth and the Moon in the camera's field of view at the same time, which made it possible to see the temporary disappearance of the Moon, according to the mission's website.
Lucy launched into space last fall and will explore one Main Belt asteroid and seven mysterious Jupiter Trojan asteroids that have never been visited by spacecraft before. Data is expected. collected by the station will allow us to characterize asteroids and better understand the processes that took place in the early solar system.
On May 15, 2022, Lucy, being at a distance of about one hundred million kilometers from Earth, was able to observe a total lunar eclipse from an unusual angle. At the time of the survey, the station was almost perpendicular to the line connecting the Earth and the Moon, keeping both celestial bodies in the field of view.
When the Moon entered the Earth's shadow, the onboard L'LORRI camera, which took pictures of the entire process, recorded the disappearance of the Moon. In total, for almost three hours of observations, the device received 86 images of the eclipse. This made it possible not only to take a fresh look at this phenomenon from deep space, but also to calibrate the device.
Previously, we talked about problems with one of the station's solar arrays, which, fortunately, will not interfere with its scientific program. Details about the scientific program "Lucy" can be found in the material "Flying around Troy" .
Alexander Voytyuk
https://nplus1.ru/news/2022/05/25/lucy-eclipse
Post by: Rondaz on 06/09/2022 01:51 am
https://twitter.com/planet4589/status/1534663079522344961
Post by: redliox on 06/10/2022 12:00 am
Post by: deadman1204 on 06/13/2022 02:34 pm
Post by: edzieba on 06/14/2022 12:15 pm
Can the tethers stretch overtime if it never latches?IIRC the tethers are Vectran, like the array gore fabric. Vectran has extraordinarily low creep (none detected at 50% breaking load over >year test timeframes), so should have no appreciable stretch over time.
Post by: Rondaz on 06/28/2022 07:58 pm
Erin Morton Posted on June 28, 2022
From May 6 to June 16, NASA’s Lucy mission team carried out a multi-stage effort intended to further deploy the spacecraft’s unlatched solar array. The team commanded the spacecraft to operate the array’s deployment motor for limited periods of time, allowing them to closely monitor the response of the spacecraft. As a result of this effort, the mission succeeded in further deploying the array and now estimates that the solar array is between 353 degrees and 357 degrees open (out of 360 total degrees for a fully deployed array). Additionally, the array is under substantially more tension, giving it significantly more stabilization. The mission team is increasingly confident the solar array will successfully meet the mission’s needs in its current tensioned and stabilized state.
Further deployment attempts will be paused as the Lucy spacecraft enters a planned period of limited communications. Due to thermal constraints caused by the relative positions of the Earth, spacecraft, and Sun, the spacecraft will be unable to communicate with the Earth via its high-gain antenna for several months. Throughout this period, the spacecraft will remain in contact with Lucy’s ground team via its low-gain antenna. The spacecraft will emerge from this partial communications blackout after its Earth gravity assist maneuver on Oct 16. At that time, the mission team will have more opportunities to attempt further deployment efforts if deemed necessary.
On June 21, the spacecraft successfully carried out a trajectory correction maneuver, which is the second in a series of maneuvers to prepare the spacecraft for its Earth flyby.
https://blogs.nasa.gov/lucy/2022/06/28/significant-progress-in-nasas-lucy-spacecraft-solar-array-deployment-efforts/
Post by: Rondaz on 07/03/2022 09:55 pm
https://twitter.com/Falcon_1e/status/1543646428265959424
Post by: Rondaz on 07/08/2022 10:17 am
https://twitter.com/SpaceIntellige3/status/1545174817183109120
Post by: FutureSpaceTourist on 08/03/2022 09:03 pm
Quote
Shortly after launch, the #LucyMission spacecraft ran into trouble with one of its solar arrays. Across millions of miles, the team found a way to troubleshoot the problem, and the mission is moving toward its next milestone. Learn how they did it: https://www.nasa.gov/feature/goddard/2022/nasa-team-troubleshoots-asteroid-bound-lucy-across-millions-of-miles
Post by: whitelancer64 on 08/03/2022 09:11 pm
*SNIP Tweet*QuoteShortly after launch, the #LucyMission spacecraft ran into trouble with one of its solar arrays. Across millions of miles, the team found a way to troubleshoot the problem, and the mission is moving toward its next milestone. Learn how they did it: https://www.nasa.gov/feature/goddard/2022/nasa-team-troubleshoots-asteroid-bound-lucy-across-millions-of-miles
"After months of simulations and testing, NASA decided to move forward with the first option – a multi-step attempt to fully redeploy the solar array. On seven occasions in May and June, the team commanded the spacecraft to simultaneously run the primary and backup solar array deployment motors. The effort succeeded, pulling in the lanyard, and further opening and tensioning the array.
The mission now estimates that Lucy’s solar array is between 353 degrees and 357 degrees open (out of 360 total degrees for a fully deployed array). While the array is not fully latched, it is under substantially more tension, making it stable enough for the spacecraft to operate as needed for mission operations.
The spacecraft is now ready and able to complete the next big mission milestone – an Earth-gravity assist in October 2022. Lucy is scheduled to arrive at its first asteroid target in 2025."
Post by: Rondaz on 08/04/2022 12:36 am
https://youtu.be/UX4cCKKFVrs
Post by: Rondaz on 08/12/2022 12:17 pm
https://twitter.com/SpaceNosey/status/1558007247283933185
Post by: edzieba on 08/12/2022 12:29 pm
The @NASA fails to fully unfold the solar panel of the #LUCY probe . After several attempts, they have managed to get the huge panel that was not fully deployed, to open between 353 and 357 degrees, of the desired 360. This will be enough for the probe to function normally.The 345° the array initially deployed to was sufficient for normal operation in terms of power output. The concern was not over deployment angle, but that the panel was sufficiently tensioned to avoid damage during subsequent manoeuvres. The dual-motor runs have aided and tensioning the array and 'jamming' the tether wrapped around the spindle in place.
https://twitter.com/SpaceNosey/status/1558007247283933185
Post by: deadman1204 on 08/12/2022 02:33 pm
The 345° the array initially deployed to was sufficient for normal operation in terms of power output. The concern was not over deployment angle, but that the panel was sufficiently tensioned to avoid damage during subsequent manoeuvres. The dual-motor runs have aided and tensioning the array and 'jamming' the tether wrapped around the spindle in place.I guess I thought the fear was shifting mass during burns throwing things off. How could this have caused damage?
Post by: edzieba on 08/13/2022 01:26 am
The arrays are fairly thin films (it's how the ultraflex/megaflex arrays achieve such high specific power), and whilst the substrate is relatively robust the conductors and cells embedded within it are not so tolerant of repeated flexing. The flexing during folding and initial deployment is well characterised, but a 'loose' array flapping around under spacecraft motion or bending in a way that folds the substrate in a manner other than the pre-folded gore pleats risks an internal conductor failure causing an open circuit & cutting off connection to parts of the array, or a short causing local heating (as well as power loss).The 345° the array initially deployed to was sufficient for normal operation in terms of power output. The concern was not over deployment angle, but that the panel was sufficiently tensioned to avoid damage during subsequent manoeuvres. The dual-motor runs have aided and tensioning the array and 'jamming' the tether wrapped around the spindle in place.I guess I thought the fear was shifting mass during burns throwing things off. How could this have caused damage?
Post by: Rondaz on 08/20/2022 11:51 am
Discovery Alert! Our #LucyMission has discovered a tiny moonlet around the Jupiter Trojan asteroid Polymele, one of the mission's targets of study. Lucy was already set to visit more asteroids than any other space mission. Add one to the roster!
https://twitter.com/SpaceNosey/status/1560939438720655360
Post by: edzieba on 08/23/2022 07:29 am
Post by: Blackstar on 08/23/2022 03:35 pm
I'd expect it to receive the temporary moniker 'Polymoon'.
Sounds like a Harry Potter character.
Post by: Comga on 08/25/2022 04:53 pm
Source article (https://www.nasa.gov/feature/goddard/2022/nasa-s-lucy-team-discovers-moon-around-asteroid-polymele) (so you don't ned to dig through tweets for the actual data). The moon is currently unnamed, (snip)
Another triumph for stellar occultation observations and the SwRI occultation chasing team.
I still think stellar occultations are marvelous. I made one of those observations myself several years ago.
Note that “observed” 125 km is the minimum distance from the newly discovered moon to Polymele, as there is nothing in this data about the third dimension, distance. It could be tens to hundreds of kilometers closer or farther than Polymele.
Quote
Using the occultation data, the team assessed that this satellite is roughly 3 miles (5 km) in diameter, orbiting Polymele, which is itself around 17 miles (27 km) along its widest axis. The observed distance between the two bodies was about 125 miles (200 km).
Credits: NASA's Goddard Space Flight Center
edit: In the image, each line is the track of the background star as projected on the plane that includes Polymele and is perpendicular to the line of sight, from the diverse observation points on the ground. The grey lines were not interrupted. The blue lines were interrupted and the points where the star disappeared and reappeared are marked. The stated sizes are the ellipses that best fit the point sets, here four for the moon and many for Polymele. (When this team caught Arrokoth, they had many interrupted tracks, and so could deduce that the shape was complex, a finding verified by the New Horizons flyby imaging of it as a contact binary.)
Post by: ddspaceman on 09/17/2022 07:59 pm
Post by: Rondaz on 10/10/2022 12:41 pm
https://twitter.com/LucyMission/status/1578790579231936513
Post by: Rondaz on 10/13/2022 11:40 am
https://twitter.com/planet4589/status/1580327888574119938
Post by: jbenton on 10/15/2022 10:34 pm
https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=14225&button=recent (https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=14225&button=recent)
https://www.nasa.gov/feature/goddard/2022/lucy-ega (https://www.nasa.gov/feature/goddard/2022/lucy-ega)
This is from the second article:
Quote
At around 6:55 a.m. EDT, Lucy will first be visible to observers on the ground in Western Australia (6:55 p.m. for those observers). Lucy will quickly pass overhead, clearly visible to the naked eye for a few minutes before disappearing at 7:02 a.m. EDT as the spacecraft passes into the Earth’s shadow. Lucy will continue over the Pacific Ocean in darkness and emerge from the Earth’s shadow at 7:26 a.m. EDT. If the clouds cooperate, sky watchers in the western United States should be able to get a view of Lucy with the aid of binoculars.
“The last time we saw the spacecraft, it was being enclosed in the payload fairing in Florida,” said Hal Levison, Lucy principal investigator at the Southwest Research Institute (SwRI) Boulder, Colorado office. “It is exciting that we will be able to stand here in Colorado and see the spacecraft again. And this time Lucy will be in the sky.”
Lucy will then rapidly recede from the Earth’s vicinity, passing by the Moon and taking a few more calibration images before continuing out into interplanetary space.
“I’m especially excited by the final few images that Lucy will take of the Moon,” said John Spencer, acting deputy project scientist at SwRI. “Counting craters to understand the collisional history of the Trojan asteroids is key to the science that Lucy will carry out, and this will be the first opportunity to calibrate Lucy’s ability to detect craters by comparing it to previous observations of the Moon by other space missions.”
The public is invited to join the #WaveToLucy social media campaign by posting images of themselves waving towards the spacecraft and tagging the @NASASolarSystem account. Additionally, if you are in an area where Lucy will be visible, take a photograph of Lucy and post it to social media with the #SpotTheSpacecraft hashtag.
EDIT: The second article also has a link to this website,http://lucy.swri.edu/SpotTheSpacecraft-EGA1.html (http://lucy.swri.edu/SpotTheSpacecraft-EGA1.html), for more detailed information on when and where to see Lucy during the flyby.
Post by: Rondaz on 10/16/2022 11:21 am
https://youtu.be/e-TEem7TmME
Post by: Rondaz on 10/16/2022 11:59 am
https://twitter.com/CanberraDSN/status/1581572144231632896
Post by: Rondaz on 10/16/2022 12:20 pm
https://twitter.com/SpaceNosey/status/1581589357886345218
Post by: Rondaz on 10/16/2022 05:11 pm
Lee Kanayama (@Falcon_1e) recaps the spacecraft's status and science to date and previews the mission's next steps:
https://twitter.com/TGMetsFan98/status/1581665049935912961
Post by: Rondaz on 10/16/2022 05:19 pm
https://twitter.com/SpaceNosey/status/1581634745930485761
Post by: Rondaz on 10/20/2022 09:32 am
https://twitter.com/tony873004/status/1582778559801659392
Post by: lrk on 10/20/2022 07:40 pm
Post by: Phil Stooke on 10/20/2022 07:50 pm
But this is a good illustration of the fact that so-called heliocentric disposal is not disposal at all. We have seen quite a few of these objects come back after varying periods - like the Apollo 12 SIVB. They represent hazards every time they pass through the Earth-Moon system. The only ways to really dispose of something are re-entering Earth's atmosphere or impact on the Moon. And since lunar impact produces potential raw materials for future lunar industry (e.g. additive manufacturing) that gets my vote.
Post by: Eric Hedman on 10/21/2022 03:57 am
I'm working on the battery!I'm curious. Is the battery modified from designs and builds for previous missions? Or do you start from scratch for this one incorporating newer technology? And do the demands on the batteries change much from mission to mission?
Post by: FutureSpaceTourist on 10/25/2022 03:19 pm
twitter.com/nasasolarsystem/status/1584927037613305857
Quote
Hello, beautiful! As the #LucyMission passed by Earth recently, it captured this look at our planet. The upper left of the image includes a view of Hadar, Ethiopia, home to the 3.2 million-year-old human ancestor fossil for which the spacecraft was named https://go.nasa.gov/3ssVDBf
https://twitter.com/nasasolarsystem/status/1584927043963457537
Quote
Lucy also snapped this family portrait of Earth and the Moon (far left, click to enlarge) from a distance of 890,000 miles (1.4 million kilometers), taken as part of an instrument calibration sequence to prepare for Lucy's upcoming asteroid explorations. More images to come!
Post by: LouScheffer on 10/25/2022 05:40 pm
Interesting. It looks like the Centaur received a significant gravitational slowdown as it passed by the Earth - I thought that it wasn't possible for a spacecraft to obtain a gravity assist/slowdown with the same body from which it departed, without an intermediate deep-space dV maneuver? And presumably the Centaur was passivated shortly after spacecraft deployment, which would preclude this?Yes, and LUCY appeared to have the opposite effect. It looked like it gained energy.
However, I think both of these are illusions based on a 2D view of 3D orbits. Both Lucy and the second stage were given a sizeable C3, and Lucy had almost no maneuvering between launch and the gravity assist (and the second state had none, as you pointed out). How then did they have a period of exactly a year (same as Earth?). The answer is a change of inclination. By picking the right inclination, one can generate a 1 year circular orbit with almost any escape velocity. Then the stage comes back to Earth, and again leaves Earth, with the same (Earth relative) velocity. Bur when viewed from a viewpoint perpendicular to Earth's orbit, it looks like it's gaining or losing energy.
Post by: edzieba on 10/26/2022 12:06 pm
By using an Earth gravity assist to bend the trajectory, you get to rob from Earth's hefty 30km/s orbital velocity to gain tangential velocity you would not be able to deliver with a direct departure. If you use this velocity gain for an inclination change with the same orbital period (or a combination of apoapsis and periapsis change with an eccentricity change), you can perform multiple passes of the same body you launched from - as Lucy will.Interesting. It looks like the Centaur received a significant gravitational slowdown as it passed by the Earth - I thought that it wasn't possible for a spacecraft to obtain a gravity assist/slowdown with the same body from which it departed, without an intermediate deep-space dV maneuver? And presumably the Centaur was passivated shortly after spacecraft deployment, which would preclude this?Yes, and LUCY appeared to have the opposite effect. It looked like it gained energy.
However, I think both of these are illusions based on a 2D view of 3D orbits. Both Lucy and the second stage were given a sizeable C3, and Lucy had almost no maneuvering between launch and the gravity assist (and the second state had none, as you pointed out). How then did they have a period of exactly a year (same as Earth?). The answer is a change of inclination. By picking the right inclination, one can generate a 1 year circular orbit with almost any escape velocity. Then the stage comes back to Earth, and again leaves Earth, with the same (Earth relative) velocity. Bur when viewed from a viewpoint perpendicular to Earth's orbit, it looks like it's gaining or losing energy.
Post by: FutureSpaceTourist on 10/26/2022 05:32 pm
Quote
Say cheese!📸🌕 Our #LucyMission captured this mosaic of the Moon on Oct. 16, hours after it flew by Earth for Lucy's first of three gravity assists. Lucy was about 140,000 miles (230,000 km) from the Moon when it took these images. Click to enlarge! go.nasa.gov/3DC9w6F
Post by: LouScheffer on 10/26/2022 05:58 pm
There is no energy gain from the first (current) Lucy flyby, only a change in direction. It does not enable you to launch with a smaller rocket. You can see this from first principles - Lucy left Earth with a relative velocity V. In the absence of a deep space maneuver (and Lucy did none) it will return with the same Earth-relative velocity (and angle) that it left with. And since a flyby does not change the planet-relative velocity, it leaves again with the same planet relative velocity V that it had at launch. Therefore it could have been launched a year later, with exactly the same rocket, just by aiming in a different direction.By using an Earth gravity assist to bend the trajectory, you get to rob from Earth's hefty 30km/s orbital velocity to gain tangential velocity you would not be able to deliver with a direct departure. If you use this velocity gain for an inclination change with the same orbital period (or a combination of apoapsis and periapsis change with an eccentricity change), you can perform multiple passes of the same body you launched from - as Lucy will.Interesting. It looks like the Centaur received a significant gravitational slowdown as it passed by the Earth - I thought that it wasn't possible for a spacecraft to obtain a gravity assist/slowdown with the same body from which it departed, without an intermediate deep-space dV maneuver? And presumably the Centaur was passivated shortly after spacecraft deployment, which would preclude this?Yes, and LUCY appeared to have the opposite effect. It looked like it gained energy.
However, I think both of these are illusions based on a 2D view of 3D orbits. Both Lucy and the second stage were given a sizeable C3, and Lucy had almost no maneuvering between launch and the gravity assist (and the second state had none, as you pointed out). How then did they have a period of exactly a year (same as Earth?). The answer is a change of inclination. By picking the right inclination, one can generate a 1 year circular orbit with almost any escape velocity. Then the stage comes back to Earth, and again leaves Earth, with the same (Earth relative) velocity. Bur when viewed from a viewpoint perpendicular to Earth's orbit, it looks like it's gaining or losing energy.
This is explicitly stated for Lucy: "The backup Lucy trajectory launches in 2022 and skips the first Earth flyby but is otherwise nearly identical to the nominal Lucy. A 2024 launch is also possible but does not include any Earth flybys and requires a large rocket to throw to a high C3." From Trajectory Design of the Lucy Mission to Explore the Diversity of the Jupiter Trojans (https://ntrs.nasa.gov/api/citations/20190032357/downloads/20190032357.pdf).
So why do a flyby that gains nothing, energy wise? There are at least two reasons. First, if there is a chance to be launched on an Ariane rocket, it's often needed since the Ariane does not do parking orbits (second stage does not restart). Hence it cannot launch in some directions. So instead they launch into an Earth-return orbit, and use the flyby to change into another otherwise inaccessible direction. Second, this strategy gives you two identical launch windows one year apart. This can help avoid problems such as befell Psyche, where they missed their launch window and the later options are much worse.
Now, between this Earth flyby and the next, Lucy will perform a fairly large Deep-Space maneuver. This changes the Earth-return velocity, and particularly the Earth orbit-spacecraft angle (which is otherwise conserved). This will result in a large gain of energy, as opposed to the current flyby. The net gain is several times larger than the magnitude of the deep space maneuver itself, which is why it is called "delta-v leveraging".
Post by: edzieba on 10/27/2022 02:30 pm
Changes in direction require significant energy. This is why plane changes are so expensive in terms of propellant.There is no energy gain from the first (current) Lucy flyby, only a change in direction.By using an Earth gravity assist to bend the trajectory, you get to rob from Earth's hefty 30km/s orbital velocity to gain tangential velocity you would not be able to deliver with a direct departure. If you use this velocity gain for an inclination change with the same orbital period (or a combination of apoapsis and periapsis change with an eccentricity change), you can perform multiple passes of the same body you launched from - as Lucy will.Interesting. It looks like the Centaur received a significant gravitational slowdown as it passed by the Earth - I thought that it wasn't possible for a spacecraft to obtain a gravity assist/slowdown with the same body from which it departed, without an intermediate deep-space dV maneuver? And presumably the Centaur was passivated shortly after spacecraft deployment, which would preclude this?Yes, and LUCY appeared to have the opposite effect. It looked like it gained energy.
However, I think both of these are illusions based on a 2D view of 3D orbits. Both Lucy and the second stage were given a sizeable C3, and Lucy had almost no maneuvering between launch and the gravity assist (and the second state had none, as you pointed out). How then did they have a period of exactly a year (same as Earth?). The answer is a change of inclination. By picking the right inclination, one can generate a 1 year circular orbit with almost any escape velocity. Then the stage comes back to Earth, and again leaves Earth, with the same (Earth relative) velocity. Bur when viewed from a viewpoint perpendicular to Earth's orbit, it looks like it's gaining or losing energy.
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You can see this from first principles - Lucy left Earth with a relative velocity V. In the absence of a deep space maneuver (and Lucy did none) it will return with the same Earth-relative velocity (and angle) that it left with. And since a flyby does not change the planet-relative velocity, it leaves again with the same planet relative velocity V that it had at launch. Therefore it could have been launched a year later, with exactly the same rocket, just by aiming in a different direction.A common error: EVERY gravity assist (that does not add an Oberth burn) will have the same velocity arriving to and departing from a target object within that target object's reference frame. That's fundamental to how a gravity assist works. The key is that in a Heliocentric frame (or any other reference frame that is not comoving with the target body) there IS a velocity change, because you are utilising the velocity of the target object in addition to the approach velocity. Whatever object you launched from is irrelevant to the vector addition involved.
Remember that Lucy has literally just performed a gravity assist that has more than doubled its orbital period and dramatically increased its apoapsis, with a near identical periapsis. That's very much a nonzero change in orbital energy, with IIRC around a 7km/s change in heliocentric velocity at periapsis.
See attached heliocentric CEs from "LUCY: NAVIGATING A JUPITER TROJAN TOUR" (AAS 17-632). Those Earth gravity assists are very much the major contributors to changes in orbit, including EGA1.
::EDIT:: Forgot to C&P the main point: the backup launch opportunity this year is a much higher energy launch than the 2021 opportunity. The reason the 2021 opportunity was targeted even though other launch vehicles had sufficient performance to be able to achieve the energy for the 2022 opportunity was because those were the ONLY two achievable launch opportunities to enter the grand tour trajectory. Targeting the first allowed the possibility to miss it and still achieve the second. Targeting only the second meant missing the opportunity forever.
Post by: LouScheffer on 10/27/2022 04:12 pm
Remember that Lucy has literally just performed a gravity assist that has more than doubled its orbital period and dramatically increased its apoapsis, with a near identical periapsis. That's very much a nonzero change in orbital energy, with IIRC around a 7km/s change in heliocentric velocity at periapsis.This seems obvious, but it's subtly wrong. The right question is "why is the initial orbit so short?". Recall Lucy launched with a C3 of 28.64 km^2/sec^2, or about 5.35 km/sec relative to Earth. This is exactly what you need to get an apogee of 1.6 AU and a period of 2 years (this is what Juno did directly, and the orbit Lucy has after the flyby). But the initial orbit had a 1 year period. What's going on?
The answer is that they applied this velocity at right angles to the Earth's orbit. This results in a 1 year orbit inclined to the Earth's orbit. Exactly a year later, the two orbits intersect again, with the same Earth relative velocity of 5.35 km/sec. This time they use the encounter to re-direct the velocity in the direction of the Earth's orbit, putting Lucy into the 1.6 AU and 2 year orbit. But the rocket's launch supplied all the energy to do that - it was simply "stored" in an orbit inclined to Earth's orbit.
You can see this more easily in a thought experiment. Imagine you had a rocket capable of an Earth relative velocity of 42 km/sec (far beyond the state of the art, and way above solar system escape of about 12 km/sec.) But instead you use this to put a probe into a 1 year orbit directly perpendicular to Earth's orbit (going directly above the poles of the Sun). In exactly one year, it returns to Earth again, coming in with the same velocity with which it left. Now you can use an Earth gravity assist to redirect it in the direction of Earth's velocity and send it screaming out of the Solar system. All that energy was added during the initial launch - it was simply stored in the difference of inclinations, where it can be losslessly retrieved by a flyby. (This would not really work since the flyby perigee for such a high speed turn would be below the Earth's surface, but it works in principle.)
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::EDIT:: Forgot to C&P the main point: the backup launch opportunity this year is a much higher energy launch than the 2021 opportunity.I suspect you will not be able to find a reference for this, since it's not true. Check the JPL Horizons spacecraft ephemeris if you doubt this. The actual launch added about 5.35 km/sec of Earth relative velocity. That's what it returned with, and what it left with again. So the launch opportunity this year had the same energy requirements as the launch last year.
Post by: briantipton on 10/27/2022 05:53 pm
Post by: LouScheffer on 10/27/2022 11:57 pm
Lucy was launched on 2021-Oct-17 at 09:34 UTC. So look at 1,2 and 3 days after:
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Ephemeris / WWW_USER Thu Oct 27 16:29:34 2022 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Lucy (spacecraft) (-49) {source: Lucy_merged_DE430}
Center body name: Earth (399) {source: Lucy_merged_DE430}
Center-site name: GEOCENTRIC
*******************************************************************************
Start time : A.D. 2021-Oct-17 09:34:00.0000 UT
Stop time : A.D. 2021-Oct-19 09:34:00.0000 UT
Step-size : 1440 minutes
*******************************************************************************
[...]
*******************************************************************************
Date__(UT)__HR:MN delta deldot
***************************************************
$$SOE
2021-Oct-17 09:34 0.00326805370796 5.4978150
2021-Oct-18 09:34 0.00641778886509 5.4262040
2021-Oct-19 09:34 0.00954475874064 5.4061152
$$EOE
*******************************************************************************
And here is Lucy for +- 3 days around flyby (16 Oct 2022, 11:04 UTC)
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Date__(UT)__HR:MN delta deldot
***************************************************
$$SOE
2022-Oct-13 11:04 0.00961975203153 -5.4009607
2022-Oct-14 11:04 0.00649734030893 -5.4153018
2022-Oct-15 11:04 0.00335601941468 -5.4780855
2022-Oct-16 11:04 0.00004508440229 -0.4001412
2022-Oct-17 11:04 0.00335539272653 5.4814037
2022-Oct-18 11:04 0.00649335231037 5.4031619
2022-Oct-19 11:04 0.00960381240196 5.3723812
$$EOE
*******************************************************************************
In particular, note that Lucy leaves the flyby with almost exactly the same Earth-relative velocity it had at launch. Since the Earth has the same heliocentric velocity at both launch and flyby (same day of the year) this means both the 2021 and 2022 windows had the same energy requirement.
Post by: edzieba on 10/28/2022 12:10 pm
In particular, note that Lucy leaves the flyby with almost exactly the same Earth-relative velocity it had at launch.Again, any gravitation assist will ALWAYS have the same target-body-relative velocity (or rather, velocity magnitude) before and after encounter. That's a fundamental requirement of a gravitational assist and tells you nothing about the heliocentric velocity, which is the velocity you are actually interested in.
If you instead ask for heliocentric, you see the change plain as day:
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Ephemeris / WWW_USER Fri Oct 28 05:09:59 2022 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Lucy (spacecraft) (-49) {source: Lucy_merged_DE430}
Center body name: Sun (10) {source: Lucy_merged_DE430}
Center-site name: BODYCENTRIC
*******************************************************************************
Start time : A.D. 2022-Oct-13 00:00:00.0000 UT
Stop time : A.D. 2022-Oct-19 00:00:00.0000 UT
Step-size : 1440 minutes
*******************************************************************************
Target pole/equ : No model available
Target radii : (unavailable)
Center geodetic : 0.00000000,0.00000000,0.0000000 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.00000000,0.00000000,0.0000000 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : IAU_SUN {East-longitude positive}
Center radii : 696000.0 x 696000.0 x 696000.0 k{Equator, meridian, pole}
Target primary : Earth (R_eq= 6378.137) km
Vis. interferer : None
Rel. light bend : Sun {source: Lucy_merged_DE430}
Rel. lght bnd GM: 1.3271E+11 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
EOP file : eop.221026.p230119
EOP coverage : DATA-BASED 1962-JAN-20 TO 2022-OCT-26. PREDICTS-> 2023-JAN-18
Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass n.a. , Daylight (NO )
Table cut-offs 2: Solar elongation ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO )
Table cut-offs 3: RA/DEC angular rate ( 0.0=NO )
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Date__(UT)__HR:MN delta deldot
***************************************************
$$SOE
2022-Oct-13 00:00 0.98682465575539 4.9115032
2022-Oct-14 00:00 0.98966366431995 4.9215899
2022-Oct-15 00:00 0.99251327922315 4.9529509
2022-Oct-16 00:00 0.99540735583089 5.1349678
2022-Oct-17 00:00 0.99719043220151 0.5163914
2022-Oct-18 00:00 0.99752560553255 0.6638734
2022-Oct-19 00:00 0.99796476198117 0.8578989
$$EOE
*******************************************************************************
Post by: LouScheffer on 10/28/2022 01:52 pm
I agree 100% with these observations. But this was not the point of the exercise.In particular, note that Lucy leaves the flyby with almost exactly the same Earth-relative velocity it had at launch.Again, any gravitation assist will ALWAYS have the same target-body-relative velocity (or rather, velocity magnitude) before and after encounter. That's a fundamental requirement of a gravitational assist and tells you nothing about the heliocentric velocity, which is the velocity you are actually interested in.
If you instead ask for heliocentric, you see the change plain as day:
The point was that the heliocentric velocity after the flyby is Earth's heliocentric velocity + Earth relative velocity of 5.35 km/sec. This Earth-relative velocity is exactly the same as what the 2021 launch provided. So if the launch occurred in the 2022 window, the exact same rocket could have launched Lucy into the exact same final orbit, without using a flyby at all.
Launching from Earth, then returning (without maneuvering) and doing an Earth flyby, results in the same trajectories that can be reached without doing a flyby. Unlike flybys of non-launch bodies, or launch-return trajectories with deep space maneuvers in between, there is no net gain when an object leaves a planet, then returns without maneuvering and does a flyby. This is because all *3* velocities (planet leaving, planet returning, planet outbound) are exactly the same, as shown in the JPL results. So by launching in the correct direction at the time of the flyby, the same rocket can deliver the same payload into the same heliocentric trajectory without using a flyby.
So there was no net benefit, in terms of heliocentric velocity achievable, to Lucy's first Earth flyby. Exactly the same final heliocentric velocity (and hence apogee, orbital period, etc.) can be obtained by the same rocket, either by direct injection at the second opportunity or by using the flyby and the first opportunity.
That being said, there are good reasons for doing two consecutive flybys of the same body (or a launch and a flyby) without a maneuver in between. These include schedule flexibility, access to launch DLA (the Ariane reason), or that making a sharp enough turn runs into the planet's surface (requiring the turn to be broken into two smaller turns). But the reason, unlike most other flybys, is not energy gain.
Post by: mn on 10/28/2022 02:32 pm
If there is a good 3D animation to explain all this it would be awesome.
Post by: edzieba on 10/28/2022 03:36 pm
If you keep using Earth-relative terms, all you will ever get is 0. You need to use Heliocentric terms.I agree 100% with these observations. But this was not the point of the exercise.In particular, note that Lucy leaves the flyby with almost exactly the same Earth-relative velocity it had at launch.Again, any gravitation assist will ALWAYS have the same target-body-relative velocity (or rather, velocity magnitude) before and after encounter. That's a fundamental requirement of a gravitational assist and tells you nothing about the heliocentric velocity, which is the velocity you are actually interested in.
If you instead ask for heliocentric, you see the change plain as day:
The point was that the heliocentric velocity after the flyby is Earth's heliocentric velocity + Earth relative velocity of 5.35 km/sec. This Earth-relative velocity is exactly the same as what the 2021 launch provided.
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*******************************************************************************
Ephemeris / WWW_USER Fri Oct 28 08:22:07 2022 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Lucy (spacecraft) (-49) {source: Lucy_merged_DE430}
Center body name: Sun (10) {source: Lucy_merged_DE430}
Center-site name: BODY CENTER
*******************************************************************************
Start time : A.D. 2022-Oct-16 00:00:00.0000 TDB
Stop time : A.D. 2022-Oct-17 00:00:00.0000 TDB
Step-size : 1440 minutes
*******************************************************************************
Center geodetic : 0.00000000,0.00000000,0.0000000 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.00000000,0.00000000,0.0000000 {E-lon(deg),Dxy(km),Dz(km)}
Center radii : 696000.0 x 696000.0 x 696000.0 k{Equator, meridian, pole}
Keplerian GM : 1.3271244004127939E+11 km^3/s^2
Output units : KM-S, deg, Julian Day Number (Tp)
Output type : GEOMETRIC osculating elements
Output format : 10
Reference frame : Ecliptic of J2000.0
*******************************************************************************
JDTDB
EC QR IN
OM W Tp
N MA TA
A AD PR
*******************************************************************************
$$SOE
2459868.500000000 = A.D. 2022-Oct-16 00:00:00.0000 TDB
EC= 1.716013900110615E-01 QR= 1.243409953437408E+08 IN= 2.276207530627643E-01
OM= 2.023807629546826E+02 W = 8.264340533115573E+01 Tp= 2459789.431403169408
N = 1.135052585797230E-05 MA= 7.754142120870668E+01 TA= 9.727279020508999E+01
A = 1.500980250864992E+08 AD= 1.758550548292577E+08 PR= 3.171659220943899E+07
2459869.500000000 = A.D. 2022-Oct-17 00:00:00.0000 TDB
EC= 4.083887192654294E-01 QR= 1.491229046335262E+08 IN= 6.860342089426681E-02
OM= 2.412284441373491E+01 W = 3.563845925466997E+02 Tp= 2459867.043434009422
N = 5.215747849477016E-06 MA= 1.107028406793846E+00 TA= 2.886415327998717E+00
A = 2.520623076158531E+08 AD= 3.550017105981801E+08 PR= 6.902174153915383E+07
$$EOE
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Semimajor axis before EGA1: 1.500980250864992 x 10^08 km
Semimajor axis after EGA1: 2.520623076158531 x 10^08 km
Specific orbital energy before EGA1: -4.42×10^8 J/kg
Specific orbital energy after EGA1: -2.633×10^8 J/kg
Vis-viva doesn't lie, Lucy gained energy from EGA1. To launch into the post-EGA1 orbit direct from Earth would require that additional energy to be provided by the launch vehicle (rather than stolen from Earth's specific orbital energy).
Gravitational assists passing by the originating body are no more or less special than any other gravitational assist. You can borrow orbital energy from the originating body just as you can from any other, there is no cosmic rulemaker preventing you from doing so.
Post by: ccdengr on 10/28/2022 04:48 pm
So if the launch occurred in the 2022 window, the exact same rocket could have launched Lucy into the exact same final orbit, without using a flyby at all.This does seem to be true: http://lucy.swri.edu/timeline/PhaseD.html says
Quote
Lucy will launch out of Cape Canaveral, Florida, in October 2021... If for some reason Lucy is unable to launch during this window, there will be another opportunity a year later.But I didn't find any discussion of this in any of the extensive literature about the mission design, which seems a bit odd if this was truly a pure form of "store in orbit" as it seems to have been.
Post by: Comga on 10/28/2022 05:15 pm
After Deep Space 1 (https://en.wikipedia.org/wiki/Deep_Space_1?wprov=sfti1)observed the “shoe last” shape of Comet Braille (https://en.wikipedia.org/wiki/9969_Braille?wprov=sfti1), JPL felt the need to add sophistication to the Impactor targeting (beyond the center of brightness).
This consumed that year, and much of the budget reserves, and most of the 1.5 years for spacecraft commissioning, but it kept the mission on track for 10P/Comet Tempel 2 (https://en.wikipedia.org/wiki/10P/Tempel?wprov=sfti1), with no change in impact velocity and the science operations
Post by: edzieba on 10/28/2022 05:59 pm
Yes, I also have had no luck finding more detail on the backup trajectory: only that there are an additional "high C3" class of trajectories available that do not include the 2022 backup launch, but "high C3" in that context was >40 km^2/s^2 so there is a wide margin above the 28.64 km^2/s^2 of the 2021 launch for the backup launch to be within. And no source has claimed that the 2022 backup launch opportunity was the same C3 as the original 2021, nor that it would be achievable on the same vehicle (Atlas V 401 is at the low end of C3 capability, so there are alternatives capable of higher C3 launches).So if the launch occurred in the 2022 window, the exact same rocket could have launched Lucy into the exact same final orbit, without using a flyby at all.This does seem to be true: http://lucy.swri.edu/timeline/PhaseD.html saysQuoteLucy will launch out of Cape Canaveral, Florida, in October 2021... If for some reason Lucy is unable to launch during this window, there will be another opportunity a year later.But I didn't find any discussion of this in any of the extensive literature about the mission design, which seems a bit odd if this was truly a pure form of "store in orbit" as it seems to have been.
Post by: LouScheffer on 10/28/2022 06:28 pm
Vis-viva doesn't lie, Lucy gained energy from EGA1. To launch into the post-EGA1 orbit direct from Earth would require that additional energy to be provided by the launch vehicle (rather than stolen from Earth's specific orbital energy).Sure, Lucy gained energy when measured in the heliocentric frame. But the energy it gained just brings it back to the energy it could have had from a direct launch. That's because the launch, very deliberately, did not put Lucy into the max possible energy orbit.
Let's look one day after the flyby:
Lucy's heliocentric speed is 35.29 km/sec
Earth's heliocentric speed is 29.88 km/sec
Lucy's launch added 5.4 km/sec.
So if the same rocket had been used for a direct launch at flyby time, and aligned with the Earth vector, the speed would be 29.88 + 5.4 = 35.28 km/sec in the heliocentric frame. This is exactly the same as the real Lucy had after the flyby. This is not a coincidence. The original launch was not in a direction designed to maximize heliocentric velocity. It was in a direction that could be converted to a max heliocentric velocity later by a flyby. But the total delta-V supplied by the rocket is the same in both cases. There was no gain in capability by using the flyby.
Quote
Gravitational assists passing by the originating body are no more or less special than any other gravitational assist. You can borrow orbital energy from the originating body just as you can from any other, there is no cosmic rulemaker preventing you from doing so.Yes, there is a cosmic rule that prevents this - it's the triangle inequality: the length of the sum of two vectors cannot be longer than the sum of the two vector lengths. Consider a spacecraft after the first of consecutive flybys, with no maneuver in between. The planet has heliocentric velocity Vp. The spacecraft has planet-relative velocity Vs. So the max possible heliocentric velocity of the probe is Vp + Vs, when the vectors align. Now consider the second flyby. The spacecraft will approach with same planet-relative velocity with which it left (Vs), and leave again with the same planet-relative velocity, Vs. The planet, assuming a circular orbit, has the same heliocentric velocity Vp. So the final maximum heliocentric velocity is again Vp + Vs. The second flyby makes no further improvement.
This can be seen a different way. The first flyby gains by aligning the planet and the probe's velocity vectors. Once these are aligned, it makes no further improvement to do another alignment - they are already as aligned as possible.
Post by: LouScheffer on 10/28/2022 06:51 pm
The "store in orbit" is certainly implied by the Lucy trajectory literature: "The backup Lucy trajectory launches in 2022 and skips the first Earth flyby but is otherwise nearly identical to the nominal Lucy. A 2024 launch is also possible but does not include any Earth flybys and requires a large rocket to throw to a high C3." From Trajectory Design of the Lucy Mission to Explore the Diversity of the Jupiter Trojans (https://ntrs.nasa.gov/api/citations/20190032357/downloads/20190032357.pdf).So if the launch occurred in the 2022 window, the exact same rocket could have launched Lucy into the exact same final orbit, without using a flyby at all.This does seem to be true: http://lucy.swri.edu/timeline/PhaseD.html saysQuoteLucy will launch out of Cape Canaveral, Florida, in October 2021... If for some reason Lucy is unable to launch during this window, there will be another opportunity a year later.But I didn't find any discussion of this in any of the extensive literature about the mission design, which seems a bit odd if this was truly a pure form of "store in orbit" as it seems to have been.
It is not stated exactly what "nearly identical" means, but I would certainly interpret this as "the already contracted rocket can be used". If you needed a bigger rocket, or a bigger model of the same rocket, this would surely not be considered "nearly identical". In addition to the increased cost of the larger rocket, presumably much of the load analysis would need to be re-done.
Post by: ccdengr on 10/28/2022 07:01 pm
And no source has claimed that the 2022 backup launch opportunity was the same C3 as the original 2021, nor that it would be achievable on the same vehicle...I did find this in https://www.planetary.org/articles/nasas-lucy-mission-gets-caught-between-rocket-companies (from the days of the SpaceX protest when ULA was picked to launch Lucy):
Quote
There is a backup launch opportunity in 2022, though this is not ideal. It is less energetically favorable (it requires more fuel) and it is less monetarily favorable (it adds another year of development costs).And when SpaceX withdrew the protest, https://spacenews.com/spacex-drops-protest-of-nasa-launch-contract/ said
Quote
Lucy must launch during a 20-day window in October 2021 in order to carry out its complex trajectory of flybys of six Trojan asteroids and one in the main asteroid belt. Should the launch miss that window, the mission cannot be flown as currently planned.But it still seems weird that none of this is described in the trajectory documents [edit: except for what Lou noted above. I suppose this could have been ULA exaggerating the extra fuel impact.]
Post by: LouScheffer on 10/28/2022 07:52 pm
I did find this in https://www.planetary.org/articles/nasas-lucy-mission-gets-caught-between-rocket-companies (from the days of the SpaceX protest when ULA was picked to launch Lucy):This is very hand-wavy, but I could easily imagine the 2022 opportunity has slightly higher C3 than 2021. From the physics, they should be identical, if both are launched at the optimum moments. NASA however requires a launch window of 20 days or so, to cope with potential delays. So the vehicle requirement is that needed at the worst edge of the launch window, which will have a C3 higher than launch on the optimum day. For a 2022 direct launch this would be unavoidable.QuoteThere is a backup launch opportunity in 2022, though this is not ideal. It is less energetically favorable (it requires more fuel) and it is less monetarily favorable (it adds another year of development costs).And when SpaceX withdrew the protest, https://spacenews.com/spacex-drops-protest-of-nasa-launch-contract/ saidQuoteLucy must launch during a 20-day window in October 2021 in order to carry out its complex trajectory of flybys of six Trojan asteroids and one in the main asteroid belt. Should the launch miss that window, the mission cannot be flown as currently planned.But it still seems weird that none of this is described in the trajectory documents [edit: except for what Lou noted above. I suppose this could have been ULA exaggerating the extra fuel impact.]
For a launch in 2021, however, a minor tweak to launch energy might be enough to bring the 2022 flyby to the optimum date. This could result in a flatter penalty curve for not launching in the center of the window, and hence a better worst case.
To add speculation on speculation, it could be that the 2021 launch was close to the limit of the Atlas 401 model chosen, making only the 2021 window feasible. (The NASA launch performance calculator no longer shows Atlas models, presumably as all Atlases are accounted for so no new missions can use one, so this is hard to check.) So it could be that to a trajectory geek the two opportunities were "nearly identical" but to ULA they were not. This would explain the statement above that if the window was missed the mission could not be completed as planned. SpaceX presumably would have bid FH with recovery, which has plenty of margin, so to SpaceX the two opportunities might have been equivalent.
Post by: LouScheffer on 10/28/2022 08:18 pm
To add speculation on speculation, it could be that the 2021 launch was close to the limit of the Atlas 401 model chosen, making only the 2021 window feasible. (The NASA launch performance calculator no longer shows Atlas models, presumably as all Atlases are accounted for so no new missions can use one, so this is hard to check.) So it could be that to a trajectory geek the two opportunities were "nearly identical" but to ULA they were not. This would explain the statement above that if the window was missed the mission could not be completed as planned. SpaceX presumably would have bid FH with recovery, which has plenty of margin, so to SpaceX the two opportunities might have been equivalent.This does not appear to be the case. From this figure (https://www.researchgate.net/figure/Payload-Mass-vs-C3-Plots-for-Delta-IV-and-Atlas-V-Launch-Vehicles_fig6_268063332), it looks like the 401 can throw about 1900 kg to a C3 of 30. Since Lucy was only 1550 kg, there should have been plenty of margin.
Post by: LouScheffer on 10/29/2022 03:46 pm
This matches well with what Lucy did. If you assume earth has a 1 au, circular orbit, then applying 5400 m/s sideways while keeping the total heliocentric velocity constant (hence keeping a = 1 au and 1 year orbit) results in an orbit with a period of 1 year and an eccentricity of 0.18. This will re-encounter the Earth in 1 year with the same 5400 m/s earth-relative.
You can mix and match combinations of inclination and eccentricity. Imagine a cone centered around the Earth's velocity vector. Any point on the rim of this cone results in an orbit that returns in 1 year. At 6 or 12 o'clock, it's a pure inclination change. At 3 or 9 o'clock, it's a pure eccentricity change. Any other angle, it's a combination. All will work.
There are practical implications of each choice. A pure eccentricity change means the perigee will be closer to the Sun than the Earth's orbit, and the spacecraft must be designed for this additional heating. A pure inclination change does not have this problem, but requires an orbital injection above the Artic (or Antarctic) circle. This costs performance from lower latitude launch sites, and is not possible for Ariane.
Post by: edzieba on 10/29/2022 09:29 pm
Let's look one day after the flyby:Lucy did not gain 5.4km/s during EGA1, it gained 10.5 km/s, as the post-encounter heliocentric velocity is 46.3 km/s, not 35.28 km/s [1].
Lucy's heliocentric speed is 35.29 km/sec
Earth's heliocentric speed is 29.88 km/sec
Lucy's launch added 5.4 km/sec.
So if the same rocket had been used for a direct launch at flyby time, and aligned with the Earth vector, the speed would be 29.88 + 5.4 = 35.28 km/sec in the heliocentric frame. This is exactly the same as the real Lucy had after the flyby.
Consider a spacecraft after the first of consecutive flybys, with no maneuver in between. The planet has heliocentric velocity Vp. The spacecraft has planet-relative velocity Vs. So the max possible heliocentric velocity of the probe is Vp + Vs, when the vectors align.Look, this is the third time now: you can't go throwing in planet-centric velocities and expect to get a useful answer, as those will always be the same on arrival and departure. You MUST use ONLY non-planet-centric (heliocentric, unless you're truly masochistic) velocities to get a valid result. Target-body-centric velocities will always remain unchanged, for any gravitation assist, of any body, anywhere, ever. Every time you try and mix reference frames like this, you'll end up with incorrect results.
You also have a second error here because of that error:
Now consider the second flyby. The spacecraft will approach with same planet-relative velocity with which it left (Vs), and leave again with the same planet-relative velocity, Vs.Because we need to use heliocentric terms, the second approach will be Vp+Vs and departure Vp+Vp+Vs.
You can see this in the table I posted earlier, where EGA2 gains a significant apogee increase even after the argument of periapsis and longitude of the ascending node changes of DSM2. And in the velocity terms for EGA1 in [1].
[1]
*******************************************************************************
Ephemeris / WWW_USER Sat Oct 29 14:22:30 2022 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Lucy (spacecraft) (-49) {source: Lucy_merged_DE430}
Center body name: Solar System Barycenter (0) {source: DE441}
Center-site name: BODY CENTER
*******************************************************************************
Start time : A.D. 2022-Oct-16 00:00:00.0000 TDB
Stop time : A.D. 2022-Oct-17 00:00:00.0000 TDB
Step-size : 1440 minutes
*******************************************************************************
Center geodetic : 0.00000000,0.00000000,0.0000000 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.00000000,0.00000000,0.0000000 {E-lon(deg),Dxy(km),Dz(km)}
Center radii : (undefined)
Output units : KM-S
Output type : GEOMETRIC cartesian states
Output format : 3 (position, velocity, LT, range, range-rate)
Reference frame : Ecliptic of J2000.0
*******************************************************************************
JDTDB
X Y Z
VX VY VZ
LT RG RR
*******************************************************************************
$$SOE
2459868.500000000 = A.D. 2022-Oct-16 00:00:00.0000 TDB
X = 1.364189998735192E+08 Y = 5.661707347071493E+07 Z = 3.154997789361700E+04
VX=-6.449117167960130E+00 VY= 2.925269969864847E+01 VZ=-1.171443814067903E-01
LT= 4.926780928853261E+02 RG= 1.477011764688442E+08 RR= 5.256670641320246E+00
2459869.500000000 = A.D. 2022-Oct-17 00:00:00.0000 TDB
X = 1.355551898851639E+08 Y = 5.934802209731743E+07 Z = 2.842320427207649E+04
VX=-1.357725197781770E+01 VY= 3.267071946192011E+01 VZ= 4.249170289851456E-02
LT= 4.936004574159977E+02 RG= 1.479776943986663E+08 RR= 6.654842051704313E-01
$$EOE
*******************************************************************************
Pre-encounter velocity magnitude: 35.8 km/s
Post-encounter velocity magnitude: 46.3 km/s
Post by: LouScheffer on 10/29/2022 10:16 pm
Could you explain how you get a post-encounter magnitude of 46.3 km/sec? Looking at the JPL report above, I see the post-encounter magnitude as sqrt(Vx^2 + Vy^2 + Vz^2), or sqrt(13.58^2 + 32.67^2 + 0.042^2) = 35.38 km/sec. This also agrees with what you get when you ask Horizons for the heliocentric velocity directly (the column VmagSn in the following output):Let's look one day after the flyby:Lucy did not gain 5.4km/s during EGA1, it gained 10.5 km/s, as the post-encounter heliocentric velocity is 46.3 km/s, not 35.28 km/s [1].
Lucy's heliocentric speed is 35.29 km/sec
Earth's heliocentric speed is 29.88 km/sec
Lucy's launch added 5.4 km/sec.
So if the same rocket had been used for a direct launch at flyby time, and aligned with the Earth vector, the speed would be 29.88 + 5.4 = 35.28 km/sec in the heliocentric frame. This is exactly the same as the real Lucy had after the flyby.
[1]
*******************************************************************************
Ephemeris / WWW_USER Sat Oct 29 14:22:30 2022 Pasadena, USA / Horizons
*******************************************************************************
Target body name: Lucy (spacecraft) (-49) {source: Lucy_merged_DE430}
Center body name: Solar System Barycenter (0) {source: DE441}
Center-site name: BODY CENTER
*******************************************************************************
Start time : A.D. 2022-Oct-16 00:00:00.0000 TDB
Stop time : A.D. 2022-Oct-17 00:00:00.0000 TDB
Step-size : 1440 minutes
*******************************************************************************
[...]
*******************************************************************************
$$SOE
2459868.500000000 = A.D. 2022-Oct-16 00:00:00.0000 TDB
X = 1.364189998735192E+08 Y = 5.661707347071493E+07 Z = 3.154997789361700E+04
VX=-6.449117167960130E+00 VY= 2.925269969864847E+01 VZ=-1.171443814067903E-01
LT= 4.926780928853261E+02 RG= 1.477011764688442E+08 RR= 5.256670641320246E+00
2459869.500000000 = A.D. 2022-Oct-17 00:00:00.0000 TDB
X = 1.355551898851639E+08 Y = 5.934802209731743E+07 Z = 2.842320427207649E+04
VX=-1.357725197781770E+01 VY= 3.267071946192011E+01 VZ= 4.249170289851456E-02
LT= 4.936004574159977E+02 RG= 1.479776943986663E+08 RR= 6.654842051704313E-01
$$EOE
*******************************************************************************
Pre-encounter velocity magnitude: 35.8 km/s
Post-encounter velocity magnitude: 46.3 km/s
Date__(UT)__HR:MN R.A._____(ICRF)_____DEC delta deldot VmagSn VmagOb
*****************************************************************************************************
$$SOE
2022-Oct-16 11:04 22 02 41.69 -13 13 19.8 0.00004508440229 -0.4001412 38.3104270 12.1114861
2022-Oct-17 11:04 06 52 49.41 +23 20 05.6 0.00335539272653 5.4814037 35.2878384 5.4844026
2022-Oct-18 11:04 06 56 51.39 +23 19 45.2 0.00649335231037 5.4031619 35.2041914 5.4039683
2022-Oct-19 11:04 06 58 13.83 +23 19 35.0 0.00960381240196 5.3723812 35.1669563 5.3727170
$$EOE
*****************************************************************************************************
Post by: LouScheffer on 10/29/2022 10:34 pm
I completely agree that one of us is ending up with incorrect results.Consider a spacecraft after the first of consecutive flybys, with no maneuver in between. The planet has heliocentric velocity Vp. The spacecraft has planet-relative velocity Vs. So the max possible heliocentric velocity of the probe is Vp + Vs, when the vectors align.Look, this is the third time now: you can't go throwing in planet-centric velocities and expect to get a useful answer, as those will always be the same on arrival and departure. You MUST use ONLY non-planet-centric (heliocentric, unless you're truly masochistic) velocities to get a valid result. Target-body-centric velocities will always remain unchanged, for any gravitation assist, of any body, anywhere, ever. Every time you try and mix reference frames like this, you'll end up with incorrect results.
You can and must mix reference frames when doing vector addition of velocities, as we are doing here. Imagine, for example, you are in a car moving 100 km/hr in ground-centric coordinates. Standing in the car, you throw a ball at 50 km/hr in car-centric coordinates. Now the ball is travelling at a max of 100 + 50 = 150 km/hr in ground coordinates, if you throw it straight forward. If you throw it backwards, it could be as little as 100 - 50 = 50 km/hr in ground coordinates. If you throw it sideways, you get sqrt(100^2+50^2) = 111.8 km/hr in ground coordinates. Substitute "heliocentric" for ground and "planet" for car, you can see you must add the planet-centric velocity of the spacecraft to the heliocentric velocity of the planet to get the heliocentric velocity of the spacecraft.
Post by: Rondaz on 10/31/2022 03:33 pm
https://youtu.be/gSHJ3uSnI-A
Post by: Rondaz on 11/18/2022 05:59 pm
Erin Morton Posted on November 18, 2022
Now that NASA’s Lucy spacecraft has successfully carried out its first Earth gravity assist, it has resumed high-data-rate communication with Earth. The Lucy spacecraft continues to operate safely and progress toward its mission goals.
Earlier this year, the team executed a series of commands to further deploy the spacecraft’s unlatched solar array. While deployment attempts were paused during a period of low-data-rate communications, the team continued to analyze the spacecraft’s telemetry and carry out ground-based tests. Based on these analyses, the team decided to continue attempts to further deploy the solar array. The likelihood of mission success in the current unlatched state is high, however the team expects that additional deployment—or potential latch—only improves confidence in performance without jeopardizing the spacecraft’s safety.
On Monday, Nov. 7, the spacecraft was instructed to point toward the Sun and operate the array deployment motors for a short period of time. As expected, the latest attempt deployed the wing incrementally forward, but it did not latch. The operation did succeed in providing the team with data to evaluate the array’s status and ascertain any changes since the last deployment attempt on June 16. During this analysis, the team identified that a small vibration occurred as the unlatched array interacted with the spacecraft’s attitude controller while the array was pointed toward Earth and at a cold temperature. The vibration did not occur as a result of the deployment activity itself. While this vibration is too small to pose a risk to the spacecraft in its current state, further array deployment attempts have been paused while the attitude controller is updated to resolve this issue. In the meantime, the spacecraft was reoriented so that the array is warmer, and the team found that the vibration is not present. The team will re-evaluate further redeployment activities once the updates to the controller are checked out on the spacecraft.
All of Lucy’s instruments functioned as expected during the gravity assist and provided an excellent test of the spacecraft’s systems and mission procedures. The team is continuing to analyze the images of the Earth and Moon collected during the flyby.
https://blogs.nasa.gov/lucy/2022/11/18/nasas-lucy-mission-provides-update-on-latest-deployment-efforts/
Post by: FutureSpaceTourist on 01/21/2023 02:55 pm
Quote
NASA quietly announced this week it's planning no further attempts to fully deploy a solar array on the Lucy spacecraft. Its current state "carries an acceptable level of risk and further deployment activities are unlikely to be beneficial at this time."
https://blogs.nasa.gov/lucy/2023/01/19/nasas-lucy-mission-suspending-further-solar-array-deployment-activities/
Quote
NASA’s Lucy Mission Suspending Further Solar Array Deployment Activities
NASA’s Lucy mission team has decided to suspend further solar array deployment activities. The team determined that operating the mission with the solar array in the current unlatched state carries an acceptable level of risk and further deployment activities are unlikely to be beneficial at this time. The spacecraft continues to make progress along its planned trajectory.
Shortly after the spacecraft’s Oct. 2021 launch, the mission team realized that one of Lucy’s two solar arrays had not properly unfurled and latched. A series of activities in 2022 succeeded in further deploying the array, placing it into a tensioned, but unlatched, state. Using engineering models calibrated by spacecraft data, the team estimates that the solar array is over 98% deployed, and it is strong enough to withstand the stresses of Lucy’s 12-year mission. The team’s confidence in the stability of the solar array was affirmed by its behavior during the close flyby of the Earth on Oct. 16, 2022, when the spacecraft flew within 243 miles (392 km) of the Earth, through the Earth’s upper atmosphere. The solar array is producing the expected level of power at the present solar range and is expected to have enough capability to perform the baseline mission with margin.
The team elected to suspend deployment attempts after the attempt on Dec. 13, 2022, produced only small movement in the solar array. Ground-based testing indicated that the deployment attempts were most productive while the spacecraft was warmer, closer to the Sun. As the spacecraft is currently 123 million miles (197 million km) from the Sun (1.3 times farther from the Sun than the Earth) and moving away at 20,000 mph (35,000 km/hr), the team does not expect further deployment attempts to be beneficial under present conditions.
Due to the energy boost that the spacecraft received during last October’s Earth gravity assist, the spacecraft is now on an orbit which will take it over 315 million miles (500 million km) from the Sun before returning to Earth for a second Earth gravity assist on Dec. 12, 2024. Over the next year and a half, the team will continue to collect data on how the solar array behaves during flight. Most significantly, the team will observe how the array behaves during a maneuver in Feb. 2024, when the spacecraft operates its main engine for the first time. As the spacecraft warms up during its approach to Earth in the fall of 2024, the team will re-evaluate if additional steps to reduce risk will be needed.
Author Erin Morton
Posted on January 19, 2023
Categories Lucy Mission
Tags Lucy
Post by: edzieba on 01/23/2023 12:47 pm
It's also not accurate to say the team is "planning no further attempts". Further attempts are being planned for when Lucy approaches closer to the Sun and warms up again - current attempts are being halted because ground testing indicates that the low temperatures are preventing further progress in reeling the tether - and whether those plans are enacted will be determined after the DSM2 burn and whether that has any effect on the array state (e.g. if it is 'well jammed' by the tether wrapped around the spindle, or whether it moves and further tightening is desirable).
Post by: vjkane on 01/25/2023 07:06 pm
NASA’s Lucy Team Announces New Asteroid Target
https://www.nasa.gov/feature/goddard/2023/nasa-s-lucy-team-announces-new-asteroid-target (https://www.nasa.gov/feature/goddard/2023/nasa-s-lucy-team-announces-new-asteroid-target)
NASA’s Lucy spacecraft will add another asteroid encounter to its 4-billion-mile journey. On Nov. 1, 2023, Lucy will get a close-up view of a small main-belt asteroid to conduct an engineering test of the spacecraft’s innovative asteroid-tracking navigation system.
The Lucy mission is already breaking records by planning to visit nine asteroids during its 12-year tour of the Jupiter Trojan asteroids, which orbit the Sun at the same distance as Jupiter. Originally, Lucy was not scheduled to get a close-up view of any asteroids until 2025, when it will fly by the main belt asteroid (52246) Donaldjohanson. However, the Lucy team identified a small, as-yet unnamed asteroid in the inner main belt, designated (152830) 1999 VD57, as a potential new and useful target for the Lucy spacecraft.
“There are millions of asteroids in the main asteroid belt,” said Raphael Marschall, Lucy collaborator of the Nice Observatory in France, who identified asteroid 1999 VD57 as an object of special interest for Lucy. “I selected 500,000 asteroids with well-defined orbits to see if Lucy might be traveling close enough to get a good look at any of them, even from a distance. This asteroid really stood out. Lucy’s trajectory as originally designed will take it within 40,000 miles of the asteroid, at least three times closer than the next closest asteroid.”
A diagram of the solar system, with the Sun a small yellow dot just off-center and Mercury, Venus, Earth, and Mars' orbits represented by colorful circles. The Lucy mission's blue orbit intersects with asteroid 1999 VD57's pink orbit.
As the NASA Lucy spacecraft travels through the inner edge of the main asteroid belt in the Fall of 2023, the spacecraft will fly by the small, as-of-yet unnamed, asteroid (152830) 1999 VD57. This graphic shows a top-down view of the Solar System indicating the spacecraft's trajectory shortly before the November 1 encounter.
Credits: NASA's Goddard Space Flight Center
The Lucy team realized that, by adding a small maneuver, the spacecraft would be able to get an even closer look at this asteroid. So, on Jan. 24, the team officially added it to Lucy’s tour as an engineering test of the spacecraft’s pioneering terminal tracking system. This new system solves a long-standing problem for flyby missions: during a spacecraft’s approach to an asteroid, it is quite difficult to determine exactly how far the spacecraft is from the asteroid, and exactly which way to point the cameras.
“In the past, most flyby missions have accounted for this uncertainty by taking a lot of images of the region where the asteroid might be, meaning low efficiency and lots of images of blank space,” said Hal Levison, Lucy principal investigator from the Southwest Research Institute Boulder, Colorado office. “Lucy will be the first flyby mission to employ this innovative and complex system to automatically track the asteroid during the encounter. This novel system will allow the team to take many more images of the target.”
It turns out that 1999 VD57 provides an excellent opportunity to validate this never-before-flown procedure. The geometry of this encounter—particularly the angle that the spacecraft approaches the asteroid relative to the Sun—is very similar to the mission’s planned Trojan asteroid encounters. This allows the team to carry out a dress rehearsal under similar conditions well in advance of the spacecraft’s main scientific targets.
This asteroid was not identified as a target earlier because it is extremely small. In fact, 1999 VD57, estimated to be a mere 0.4 miles (700 m) in size, will be the smallest main belt asteroid ever visited by a spacecraft. It is much more similar in size to the near-Earth asteroids visited by recent NASA missions OSIRIS-REx and DART than to previously visited main belt asteroids.
The Lucy team will carry out a series of maneuvers starting in early May 2023 to place the spacecraft on a trajectory that will pass approximately 280 miles (450 km) from this small asteroid.
Lucy’s principal investigator 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
Post by: Phil Stooke on 01/25/2023 09:57 pm
True, and sounds like a good thing. But I will point out that it was those images of blank space which enabled the discovery of 243 Ida's little satellite Dactyl (the first asteroid satellite to be confirmed) during the Galileo mission. However, I would expect to see dedicated satellite searches during the Lucy asteroid encounters, so nothing likely to be lost.
Post by: deadman1204 on 01/26/2023 02:35 pm
“In the past, most flyby missions have accounted for this uncertainty by taking a lot of images of the region where the asteroid might be, meaning low efficiency and lots of images of blank space,” said Hal Levison...Didn't new horizons run som algorithm to discard alot of their blank images from the pluto encounter instead of wasting bandwidth on downloading them?
True, and sounds like a good thing. But I will point out that it was those images of blank space which enabled the discovery of 243 Ida's little satellite Dactyl (the first asteroid satellite to be confirmed) during the Galileo mission. However, I would expect to see dedicated satellite searches during the Lucy asteroid encounters, so nothing likely to be lost.
Post by: Phil Stooke on 01/26/2023 08:59 pm
Post by: mmonty on 01/26/2023 10:02 pm
Don't know about every instrument, but Ralph observations were planned in advance and took into account possible pointing/slew errors and uncertainty in where Pluto would be in the field-of-view.“In the past, most flyby missions have accounted for this uncertainty by taking a lot of images of the region where the asteroid might be, meaning low efficiency and lots of images of blank space,” said Hal Levison...Didn't new horizons run som algorithm to discard alot of their blank images from the pluto encounter instead of wasting bandwidth on downloading them?
True, and sounds like a good thing. But I will point out that it was those images of blank space which enabled the discovery of 243 Ida's little satellite Dactyl (the first asteroid satellite to be confirmed) during the Galileo mission. However, I would expect to see dedicated satellite searches during the Lucy asteroid encounters, so nothing likely to be lost.
Post by: Sam Ho on 01/30/2023 10:09 pm
Don't know about every instrument, but Ralph observations were planned in advance and took into account possible pointing/slew errors and uncertainty in where Pluto would be in the field-of-view.“In the past, most flyby missions have accounted for this uncertainty by taking a lot of images of the region where the asteroid might be, meaning low efficiency and lots of images of blank space,” said Hal Levison...Didn't new horizons run som algorithm to discard alot of their blank images from the pluto encounter instead of wasting bandwidth on downloading them?
True, and sounds like a good thing. But I will point out that it was those images of blank space which enabled the discovery of 243 Ida's little satellite Dactyl (the first asteroid satellite to be confirmed) during the Galileo mission. However, I would expect to see dedicated satellite searches during the Lucy asteroid encounters, so nothing likely to be lost.
New Horizons could do both lossy and lossless compression, along with subframing. From Section 5.3:
Quote
The New Horizons software implements both lossless and lossy compression. Nonpacketized science data are read off of the SSR, compressed and formed into CCSDS packets, and written back to the SSR. There is also the option to read the non-packetized science data off of the SSR, form the data into CCSDS packets without doing any sort of compression, and write the data back to the SSR.Fountain, G.H., Kusnierkiewicz, D.Y., Hersman, C.B. et al. The New Horizons Spacecraft. Space Sci Rev 140, 23–47 (2008). https://doi.org/10.1007/s11214-008-9374-8
Lossless compression can be combined with subframing, or windowing. Rather than performing the lossless compression on the entire image, it is possible to specify up to eight subframes of the image and then perform the lossless compression on the data within these subframes.
Preprint at https://www.boulder.swri.edu/pkb/ssr/ssr-fountain.pdf
The Galileo Ida encounter imagery used ‘‘jailbar search’’ to find the most interesting frame segments to return.
Quote
The initial playback, immediately following encounter, was designed to locate the highest priority data and the high-resolution mosaics HIRES and ENCNTR, on the tape. A technique dubbed ‘‘jailbar search’’ was used in which only two or three image lines out of every 330 were extracted off the tape and returned to Earth from all 45 frames in these two mosaics. From these sparse image segments, together with the most probable Ida shape solutions determined from ground-based lightcurve data (cf. Thomas et al. 1996), it was possible to determine which images contained Ida and also make more accurate estimates of Ida’s size, shape, and pole orientation. Using this information, the segments of frames (cf. Table IIB) containing Ida in these mosaics were selected for full rate playback.
Dactyl turned up in the jailbar search:
Quote
The first data returned were jailbar searches of the color sequences acquired between 222 and 210 min. from encounter and of some of the early rotation data obtained on approach. It was during the examination of these data that, on Feb. 17, 1994, Dactyl, a natural satellite of Ida was discovered (Belton and Carlson 1994).Michael J.S. Belton, Clark R. Chapman, Kenneth P. Klaasen, Ann P. Harch, Peter C. Thomas, Joseph Veverka, Alfred S. McEwen, Robert T. Pappalardo. Galileo's Encounter with 243 Ida: An Overview of the Imaging Experiment, Icarus 120, 1-19, (1996), ISSN 0019-1035, https://doi.org/10.1006/icar.1996.0032.
(https://www.sciencedirect.com/science/article/pii/S0019103596900329)
Galileo used a much more aggressive lossy Integer Cosine Transform compression (a relative of JPEG) for most of the mission after Jupiter arrival.
See, for example, this review paper:
Beser, Nicholas D. Space Data Compression Standards. Johns Hopkins APL Technical Digest, Volume 15, Number 3, 206-223 (1994). https://www.jhuapl.edu/Content/techdigest/pdf/V15-N03/15-03-Beser.pdf
Post by: Comga on 01/30/2023 10:22 pm
Every Ralph frame was planned in advance.
New Horizons could do lossy and lossless compression.
However, after seeing some of the artifacts from that lossy compression, it was switched off and the entire volume of stored data, including frames where nothing was expected, were downlinked losslessly.
(They may still be downlinking the very last, lowest priority data along with currrent data like the Student Dust Counter, SWAP, PEPSI, and LORRI’s Cosmic Optical Background images.)
Post by: deadman1204 on 01/31/2023 02:21 pm
It isn’t clear how this is relevant to Lucy, but both of you are correct.The discussion was based around the fact that it wasn't known how many shots would totally miss the target. We don't have a perfect position for Lucy targets (nor did we have one for pluto). There was good estimates, but the margin of error wasn't insignificant.
Every Ralph frame was planned in advance.
New Horizons could do lossy and lossless compression.
However, after seeing some of the artifacts from that lossy compression, it was switched off and the entire volume of stored data, including frames where nothing was expected, were downlinked losslessly.
(They may still be downlinking the very last, lowest priority data along with currrent data like the Student Dust Counter, SWAP, PEPSI, and LORRI’s Cosmic Optical Background images.)
Post by: Targeteer on 03/20/2023 02:17 pm
Characterisation of the new target of the NASA Lucy mission: asteroid 152830 Dinkinesh (1999 VD57)
J. de León, J. Licandro, N. Pinilla-Alonso, N. Moskovitz, T. Kareta, M. Popescu
The NASA Lucy mission is aimed at the study of the very interesting population of Jupiter Trojans, considered as time capsules from the origin of our solar system. During its journey, the mission will pass near a main belt asteroid, Donaldjohanson. Recently, NASA has announced that a new asteroid in the belt will also be visited by Lucy: 152830 Dinkinesh (1999 VD57). The main goal of this work is to characterise this newly selected target, asteroid Dinkinesh, in order to provide critical information to the mission team. To achieve it, we have obtained visible spectra, colour photometry, and time-series photometry of Dinkinesh, using several telescopes located at different observatories. For the spectra we used the 10.4m Gran Telescopio Canarias (GTC), in the island of La Palma (Spain); for the colour photometry the 4.3m Lowell Discovery Telescope (LDT), near Happy Jack, Arizona (USA) was used; and for the time-series photometry we used the 82cm IAC80 telescope located in the island of Tenerife (Spain). Both visible spectrum and reflectance values computed from colour photometry show that Dinkinesh is an S-type asteroid, i.e., it is composed mainly of silicates and some metal. According to observations done by the NEOWISE survey, S-type asteroids have typical geometric albedo of pV = 0.223 ± 0.073. From our time-series photometry, we obtained an asteroid mean magnitude r′ = 19.99 ± 0.05, which provides an absolute magnitude Hr′ = 17.53 ± 0.07 assuming G = 0.19 ± 0.25 for S-types. Using our colour-photometry, we transformed Hr′ to HV = 17.48 ± 0.05. This value of absolute magnitude combined with the geometric albedo provides a mean diameter for Dinkinesh of ∼900 m, ranging between a minimum size of 542 m and a maximum size of 1309 m.
Comments: 4 pages, 3 figures, Accepted for publication in A&A
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2303.05918 [astro-ph.EP]
(or arXiv:2303.05918v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2303.05918
Post by: Targeteer on 04/16/2023 06:16 pm
Apr 13, 2023
NASA’s Lucy Mission Snaps its First Views of Trojan Asteroid Targets
Four animated images are shown side-by-side horizontally. They are dotted with dozens of bright spots, stars, on a dark background. Little specs, Trojan asteroids photographed by the Lucy spacecraft, are circled and moving slightly across each image.
This story was updated at 4:30 p.m. EST on April 13 to indicate that Lucy will visit two main belt asteroids rather than one.
Some of the asteroids NASA’s Lucy mission will visit are still more than 330 million miles (530 million kilometers) away from the spacecraft, which is more than three times the average distance between Earth and the Sun. But despite the great distance and the comparatively small sizes of these asteroids, Lucy caught views of four of them recently.
From March 25 to 27, 2023, Lucy used its highest resolution imager, L’LORRI, to capture its first views of four Jupiter Trojan asteroids. From left to right in the above image: Eurybates, Polymele, Leucus, and Orus.
Although the four images are all at the same scale, the orientation of each is different, reflecting the different orientations of the L’LORRI camera as it turned to capture each target.
The targets were also observed for different time periods based on their rotation periods:
Eurybates images were taken over a span of 6.5 hours.
Polymele, about 2.5 hours.
Leucus, 2 hours.
Orus, 10 hours.
Learn more about NASA's Lucy mission.
These images are the first in a series of planned observations designed to measure how the Trojan asteroids reflect light at higher angles than is observable from Earth. Though the asteroids are still just single points of light in these images, seen against a background of distant stars, the data will help the team choose exposure times for Lucy’s close-up observations of its targets.
Lucy will fly by these asteroids in 2027 and 2028 as the spacecraft travels through a swarm of small asteroids that lead Jupiter in its orbit around the Sun. Lucy is just more than a year into a 12-year voyage that entails close observation of nine of Jupiter’s Trojans — the first space mission ever to visit them — and two main belt asteroids.
By Katherine Kretke
Southwest Research Institute
Image credit: NASA/Goddard/SwRI/JHU-APL
Post by: Targeteer on 05/20/2023 07:38 am
NASA’s Lucy Spacecraft Adjusts Course for Asteroid Flyby in November
On May 9, NASA’s Lucy spacecraft carried out a trajectory correction maneuver to set the spacecraft on course for its close encounter with the small main belt asteroid Dinkinesh. The maneuver changed the velocity of the spacecraft by only about 7.7 mph (3.4 m/s).
Even though the spacecraft is currently travelling at approximately 43,000 mph (19.4 km/s), this small nudge is enough to move the spacecraft nearly 40,000 miles (65,000 km) closer to the asteroid during the planned encounter on Nov. 1, 2023. The spacecraft will fly a mere 265 miles (425 km) from the small, half-mile- (sub-km)-sized asteroid, while travelling at a relative speed of 10,000 mph (4.5 km/s).
The Lucy team will continue to monitor the spacecraft’s trajectory and will have further opportunities to fine tune the flight path if needed.
The Lucy team is also continuing to analyze the data collected from its spring instrument calibration campaign and make other preparations for the mission’s first asteroid encounter. This encounter will provide a valuable test of the spacecraft’s systems and procedures to make sure that everything operates as expected during the mission’s high-speed asteroid encounters.
Post by: Targeteer on 05/27/2023 06:21 pm
https://www.nasa.gov/sites/default/files/atoms/audio/ep289_lucy.mp3
Post by: ddspaceman on 09/12/2023 08:34 pm
@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
Post by: FutureSpaceTourist on 10/19/2023 07:29 pm
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.
https://youtu.be/tzcosX_HIo4QuoteOn 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
Post by: vjkane on 10/26/2023 03:10 pm
L’Ralph: A Visible/Infrared Spectral Imager for the Lucy Mission to the Trojans (http://"https://link.springer.com/article/10.1007/s11214-023-01009-2")
The paper is open access.
Post by: FutureSpaceTourist on 11/01/2023 03:36 pm
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:
Quote
A 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
Post by: FutureSpaceTourist on 11/01/2023 07:05 pm
Quote
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
Post by: Blackstar on 11/02/2023 05:35 pm
https://www.nasa.gov/image-article/nasas-lucy-spacecraft-discovers-2nd-asteroid-during-dinkinesh-flyby/
Post by: sdsds on 11/02/2023 05:48 pm
Post by: Blackstar on 11/02/2023 07:12 pm
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.
Post by: Zed_Noir on 11/02/2023 10:51 pm
Post by: Blackstar on 11/02/2023 10:58 pm
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.
Post by: CuddlyRocket on 11/03/2023 06:01 am
--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.
Post by: jgoldader on 11/03/2023 09:04 am
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.
Post by: Phil Stooke on 11/03/2023 10:58 pm
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.
Post by: Don2 on 11/04/2023 09:19 pm
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.
Post by: FossilDS on 11/07/2023 06:28 pm
...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 (https://science.nasa.gov/missions/lucy/nasas-lucy-surprises-again-observes-1st-ever-contact-binary-orbiting-asteroid/)
Post by: ddspaceman on 11/29/2023 04:55 pm
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.
Post by: Blackstar on 02/01/2024 04:38 pm
Here are some slides.
Post by: zubenelgenubi on 02/01/2024 07:37 pm
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?
Post by: Blackstar on 02/01/2024 09:43 pm
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.
Post by: Phil Stooke on 02/01/2024 11:02 pm