The Lucy spacecraft and one of its two solar arrays, 7.3 meters in diameter, during tests before its Oct. 16 launch. Credit: Lockheed Martin
WASHINGTON — Engineers are investigating why one of the two solar arrays on NASA’s Lucy spacecraft may have failed to lock into place when deployed after launch Oct. 16.
In an Oct. 17 statement, NASA said that while the spacecraft is healthy, one of the two circular solar panels “may not be fully latched” after its deployment. The solar arrays deployed in the first half-hour after separation from the Centaur upper stage of the Atlas 5 rocket that launched it early Oct. 16.
Both solar panels are generating power, the agency stated, and there are no other problems with the spacecraft. “In the current spacecraft attitude, Lucy can continue to operate with no threat to its health and safety,” NASA said in the statement. “The team is analyzing spacecraft data to understand the situation and determine next steps to achieve full deployment of the solar array.”
“This team has overcome many challenges already and I am confident they will prevail here as well,” Thomas Zurbuchen, NASA associate administrator for science, tweeted Oct. 17.
Lucy’s two solar panels are each 7.3 meters in diameter. Stored in a folded configuration, they were designed to unfurl “like Chinese fans,” said Joan Salute, associate director for flight programs in NASA’s planetary science division, at a prelaunch briefing Oct. 14.
The arrays have a combined 51 square meters of solar cells. That large area is needed since the spacecraft will be flying out to Jupiter’s distance from the sun, where the sunlight is only a few percent as powerful as at Earth. “That enables Lucy to travel further away from the sun than any other solar-powered spacecraft to date,” said Katie Oakman, Lucy structures and mechanisms lead at Lockheed Martin Space, at the Oct. 14 briefing. Lockheed was the prime contractor for Lucy, although the solar arrays were built by Northrop Grumman.
In the vicinity of the Earth, Lucy’s panels can generate 18 kilowatts of power. However, when flying by the Trojan asteroids that are the destination of the mission, the arrays will produce only 500 watts of power, still sufficient to operate the spacecraft and its three main instruments.
She added there was no specific design requirement for circular arrays versus more conventional rectangular ones, but that those offered the most area while fitting in the confines of the Atlas payload fairing. “This particular design really enables us to stow up closely and tightly next to the spacecraft for launch,” she said. “Having any particular shape other than this really unique design wouldn’t enable us to get to that 51-meter-squared of active cell area and still fit within the launch vehicle fairing.”
It’s unclear if the problem will affect other work to check out the spacecraft after its launch. That includes deployment of the instrument pointing platform, on which the three major instruments are mounted, which is scheduled for about two days after launch.
Quelle: SN
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NASA studying solar array issue with Lucy asteroid probe
NASA's $1 billion Lucy asteroid probe is safely on its way, but engineers are studying telemetry indicating one of its two circular solar arrays may not be fully deployed and latched in place, the agency said in a blog post Sunday.
Lucy was launched from Cape Canaveral early Saturday atop a United Launch Alliance Atlas 5 rocket and released on a trajectory setting up two velocity-boosting gravity-assist Earth flybys in 2022 and 2024 to fling the craft out to a swarm of asteroids sharing Jupiter's orbit.
A third Earth flyby is planned for 2030 to send the craft to a pair of asteroids in another "Trojan" swarm in 2033.
Two frames from a computer animation produced by NASA's Goddard Space Flight Center show how the Lucy asteroid probe's two solar arrays are designed to unfold in a circular fashion. Telemetry indicates one of the two arrays may not have locked in the fully open position after launch Saturday.NASANASA
Built by Lockheed Martin Space, Lucy will be operating farther from the sun than any other solar-powered spacecraft before it, and its two Northrop Grumman-built arrays, designed to unfold 360 degrees like Chinese fans, are critical to mission success.
Shortly after launch Saturday, NASA confirmed both 24-foot-wide arrays had deployed and were generating power. But on Sunday, the agency said one of the arrays may not be latched in place.
"Following a successful launch ... analysis of NASA's Lucy spacecraft systems show the spacecraft is operating well and is stable," the blog post said. "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."
An artist's impression of the Lucy probe as it flies past a Trojan asteroid.NASA
It's not yet clear whether the array in question is, in fact, fully deployed but not latched in place or whether it did not reach full deployment and is not generating the same amount of power as its counterpart. It's also not yet clear whether Lucy can safely fire its maneuvering thrusters with an unlatched array.
Thomas Zurbuchen, NASA's science chief, said he was confident engineers will resolve the problem.
"The two solar arrays have deployed, but one may not be fully latched," he tweeted. "The team is analyzing data to determine next steps. This team has overcome many challenges already and I am confident they will prevail here as well."
Whether intentional or not, Zurbuchen's tweet included a frame from the Goddard animation above showing one array fully deployed and one with a gap indicating a partial deployment.
Quelle: CBS News
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Update: 20.10.2021
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NASA officials optimistic Lucy asteroid mission will overcome solar array snag
Artist’s illustration of the final phase of deploying the solar arrays on NASA’s Lucy spacecraft. Credit: NASA
A NASA official said Monday there is “widespread optimism” that a solar array snag discovered on the Lucy asteroid probe after its launch over the weekend will not jeopardize the spacecraft’s 12-year exploration mission.
Lucy’s two solar arrays were folded up on each side of the box-shaped spacecraft during launch Saturday from Cape Canaveral aboard an Atlas 5 rocket. One of the two solar array wings fully unfurled and latched after launch, but NASA says it did not receive confirmation that the other wing latched into place.
The Atlas 5 deployed the Lucy probe nearly an hour after liftoff, sending the 3,300-pound (1,500-pound) spacecraft on an escape trajectory into the solar system. The launch kicked off a $981 million mission to explore the Trojan asteroids, a primordial population of small worlds leading and trailing Jupiter in its orbit around the sun.
Lucy is the mission is the first to explore the Trojan asteroids, which scientists say are leftover building blocks similar to objects that came together to form the solar systems giant outer planets. The probe will fly by seven Trojan asteroids between 2027 and 2033, plus one object in the main asteroid belt in 2025.
A few minutes after separating from the Atlas 5 launcher, Lucy began a pre-programmed sequence to unfold the solar arrays like giant Chinese fans. Fully deployed, the UltraFlex solar wings span about 24 feet (7.3 meters) in diameter, the circular power arrays to ever fly in space.
Both solar arrays are generating power, and Lucy’s batteries are fully charged, said Lori Glaze, director of NASA’s planetary science division.
“The spacecraft is stable and healthy, and it’s safe,” Glaze said Monday in a virtual town hall meeting by NASA’s science mission directorate. “It’s not in any danger, at this point, in this configuration. So we are taking our time in determining what’s going on with the solar array, and developing a path forward on how to remediate.”
“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.
“We don’t know if it’s a latch problem, or that it is only partially deployed,” Salute said.
Lucy will become the farthest spacecraft from the sun to ever rely on solar power, reaching a maximum distance of 530 million miles (853 million kilometers), nearly six times farther than Earth’s orbit. When it reaches the Trojan asteroids, Lucy’s solar arrays were expected to generate just 500 watts of power.
That level power output is sufficient to feed Lucy’s three science instruments, which only need about 82 watts of power during each asteroid encounter. Lucy’s flight computer, communications system, and other components will also draw on power generated by the UltraFlex arrays.
Salute said controllers may attempt to command Lucy to re-attempt a full deployment of the solar array.
“They’re checking different analyses, making sure that that would be safe to implement,” she said. “One of the steps that they would be taking in the fairly short term would be to provide a second attempt at full deployment and latching.”
The UltraFlex solar arrays on NASA’s Lucy spacecraft unfold during a ground test at a Lockheed Martin test facility in Colorado. Credit: Lockheed Martin
Lockheed Martin, the prime contractor for the Lucy spacecraft, oversees mission operations from a control center near Denver.
Although the solar arrays are generating sufficient power, engineers are also evaluating whether it is safe to fire the spacecraft’s main engine with an unlatched solar array. The mission’s first major deep space maneuver is tentatively scheduled for mid-November.
“At this point in time, they hope to go ahead with that maneuver, but it is too early to tell,” Salute said.
The spacecraft has continued firing its smaller attitude control thrusters without any issues, she said.
“They just want to really get a little more understanding under their belt about which would be safer — to re-deploy or to operate as is,” Salute said. “And I don’t think they have a firm answer on that option quite yet.”
Managers have postponed one other major post-launch activity to allow engineers to address the solar array issue. Lucy’s instrument platform was supposed to release and deploy two days after launch. That has been temporarily put on hold, according to Salute.
“There’s still widespread optimism that this can be overcome, or worked with,” Salute said.
Quelle: SN
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Update: 10.12.2021
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NASA Zeroing in on Path Forward for Lucy Solar Array
NASA plans to conduct additional ground tests on an engineering model of the Lucy 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.
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Lucy Instruments Checkout A-OK
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.
Quelle: NASA
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Update: 27.01.2022
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Cause of Lucy solar array deployment problem identified
Engineers believe they know why one of the two solar arrays on the Lucy spacecraft failed to fully deploy, but are still studying whether to try to redeploy the array. Credit: Lockheed Martin
WASHINGTON — Engineers have identified the likely reason one of two solar arrays on NASA’s Lucy asteroid mission failed to latch in place after launch, but NASA is still studying whether to fix the problem.
At a Jan. 25 meeting NASA’s Small Bodies Assessment Group, Hal Levison, principal investigator for Lucy at the Southwest Research Institute, expressed confidence that, regardless if the solar array is fully deployed or not, the issue will not affect the spacecraft’s ability to carry out its mission to study several Trojan asteroids leading and following Jupiter in its orbit around the sun.
Shortly after its Oct. 16 launch, deployed two large circular solar arrays, each 7.3 meters in diameter. The arrays are designed to unfurl like fans and latch into place. While one array, called -Y, did completely unfurl and latch, the other, +Y, did not latch into place.
“People have been working day and night since the launch to try and figure out what’s going on, and I think we understand it,” Levison said. The +Y array, rather than unfurling a full 360 degrees, instead went 347 degrees. In that configuration, the spacecraft is still generating more than 90% of its expected power. “Power is not an issue for the spacecraft, nor will it be through the entire mission if we have to fly it like it is.”
The arrays unfurl when a motor pulls on a lanyard, swinging one end of the array around and into place. Levison said that the most likely reason the array did not latch is that, for some reason, there was a loss of tension in the lanyard during deployment. That caused it to fall off a spool and wrap around the motor shaft. About 75 centimeters of lanyard remains to be pulled in.
“It matches the data really well, so we have really high confidence this is true,” he said. One possible cause of the loss of tension, he added, is a “dynamic interaction” between the two arrays during the deployment.
Mission managers are considering two alternatives. One is to turn the motors back on and try to bring in the remaining lanyard segment so that the array can lock into place. “We’re almost there, so I think if we can pull a little harder, we might be able to get it to latch,” he said. The motor can pull harder, he said, but engineers want to assess the risks of doing so before making another attempt.
The other option is to keep the array as is. While the array can generate enough power without being fully deployed, Levison said engineers want to study its integrity in that configuration during main engine burns. “The analysis so far is looking good. We should be able to do at least some of the main engine burns we’re planning.”
There’s no rush to decide whether to redeploy the array or leave it as is. “We have plenty of time because we’re not scheduled to fire the main engine for a while,” he said. “We’re taking our time to carefully go through our options.”
That assessment matches the most recent NASA update about the mission, published Jan. 12. It stated that the current plan for the mission “supports a latch attempt in the late April timeframe” but that engineers were still studying leaving the array in its current unlatched condition.
Levison added that all other aspects of the spacecraft, including its instruments, were working well. “Except for this problem, the spacecraft is really kicking butt,” he said. “The instruments and the spacecraft are all behaving nominally.”
Quelle: SN
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Update: 24.04.2022
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Lucy is "Go" for solar array deployment attempt
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.
Quelle: SD
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NASA's Lucy asteroid probe will watch the Super Flower Blood Moon eclipse from deep space
Lucy will have a unique view of the lunar eclipse happening May 15 to 16.
A simulation of how the Earth and moon will appear to the Lucy spacecraft around the time of the total lunar eclipse on May 15, 2022.(Image credit: NASA/SwRI)
Like a flashlight beam penetrating the dark, the moon's reflected sunlight will blink on and off during a lunar eclipse just visible by an asteroid-bound spacecraft.
A NASA spacecraft called Lucy plans to take a side view of the Super Flower Blood Mmoon lunar eclipse of May 15 on its way to visit clusters of asteroids that orbit the sun at about the same distance as Jupiter, called Trojans. The spacecraft, which launched in October 2021, is on a path back to Earth for a gravity assist to the outer solar system in October, but right now the spacecraft is still far away: roughly 70% of the distance between Earth and the sun. You can watch the Flower Blood Moon eclipse in webcasts, starting at 9:30 p.m. EDT (0130 GMT).
Regardless, at least some of the high-definition cameras on the spacecraft should (in theory) be able to see the moon passing into the Earth's shadow in the lunar eclipse on May 15 and 16, according to officials with the Southwest Research Institute in Colorado, where the mission's main science team is based.
"From this distance, Lucy will view the eclipse from an angle rarely seen," officials stated in a press release Thursday (May 12). "To Lucy, the gibbous Earth and moon will be easily visible. As the moon enters the shadow of the Earth it will blink out, [and] no longer be visible, until it moves again out of the Earth's shadow."
To see the eclipse in action, Lucy will perform imaging using its L'LORRI (Lucy Long Range Reconnaissance Imager)high resolution panchromatic camera. That's a next-generation instrument based on a version that flew on the New Horizons spacecraft that whizzed by Pluto and is visiting other asteroids in the faraway Kuiper Belt.
The press release hinted that other imagers may be involved, but did not offer specifics. Lucy carries a few other such instruments. There's L'Ralph, a "two in one" instrument with a color camera (the Multispectral Visible Imaging Camera, MVIC) and infrared imaging spectrometer (Linear Etalon Imaging Spectral Array, LEISA).
Additionally, during Lucy's main mission, the Terminal Tracking Cameras (T2CAM) provide wide-field imaging and L'TES, the infrared Thermal Emission Spectrometer, will measure the surface temperature of target asteroids.
"Viewing this eclipse will allow the Lucy team to do a 'test run' of the observation procedures, making sure that all the imagers and equipment are working as expected," SwRI stated. "It is also a fun opportunity as it is extremely rare to get real images of astronomical events like this, from such a unique vantage point."
On Earth, the Flower Moon's eclipse will be visible in total phase from portions of the Americas, Antarctica, Europe, Africa and the east Pacific. A penumbral eclipse (where the edge of Earth's shadow will fall over the moon) is visible in New Zealand, eastern Europe and the Middle East, although this type of eclipse is difficult to observe.
While timing depends on your location, TimeandDate.com says the partial eclipse phase of the moon eclipse begins May 15 at 10:28 p.m. EDT (0228 GMT on May 16). It will get to the red-hued Blood Moon peak May 16 at 12:11 a.m. EDT (0411 GMT). Then the event ends at 1:55 a.m. EDT (0555 GMT). Note the penumbral eclipse will begin about an hour earlier and end about an hour after the partial eclipse.
The principal investigator for NASA’s Lucy asteroid mission says he thinks it’s like the mission can operate as planned even if one of two solar arrays does not fully deploy and latch, based on recent progress tensioning the array. Credit: Lockheed Martin
WASHINGTON — Leaders of NASA’s Lucy asteroid mission are increasingly confident that the mission can continue as planned even if ongoing efforts to fully deploy and latch a solar array don’t succeed.
On May 9, controllers issued commands to run both the primary and backup motors for the solar array deployment process simultaneously, hoping that a harder pull would be sufficient to restore tension in the lanyard and continue deployment of the array. The spacecraft similarly ran both motors three times since then.
“That’s allowing us to make significant process towards latch, but we’re not latched yet,” Hal Levison, principal investigator for Lucy at the Southwest Research Institute, said in a presentation at a meeting of NASA’s Small Bodies Assessment Group June 8. “We are seeing significant tensioning of the array.”
That tensioning, he said, is a positive sign even though the array has not latched into place. “It makes it likely that, even if we don’t get the thing latched, we’ll be able to fly the mission as-is,” he said, noting the array, in its current configuration, is generating more than 90% of its planned power.
The mission is preparing for an Earth gravity-assist flyby in October, when the spacecraft will pass about 350 kilometers above the Earth. After a second Earth flyby in 2024, Lucy will go past an asteroid in the main belt in 2025, then several Trojan asteroids in a cluster leading Jupiter in orbit around the sun in 2027 and 2028. A third Earth flyby in 2030 will set up encounters with two Trojan asteroids in a separate cluster trailing Jupiter in 2033.
To set up the October flyby, Lucy performed a trajectory correction maneuver June 7, NASA said in a June 8 blog post. The maneuver is the first of several planned before the October flyby.
Quelle: SN
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Update: 20.06.2022
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NASA's Lucy mission adds 9th asteroid to its list of attractions
The asteroid still doesn't have a name, and it likely won't for a while
Artist's depictions of the eight asteroids that NASA's Lucy mission will visit.(Image credit: NASA Goddard/YouTube)
NASA's Lucy probe has gained a ninth asteroid destination for its 12-year mission.
Lucy launched in October 2021 and is bound for the Trojan asteroids, which, thanks to the pull of Jupiter's immense gravity, ride in the gas giant's orbit ahead of and behind the behemoth. In 2027, Lucy will become the first human-made object to fly past one of these asteroids.
The mission was designed to zoom past a main-belt asteroid then swing through a complicated itinerary of Trojan asteroids. And now, scientists have determined that one of Lucy's original target asteroids has a companion: another, tiny asteroid that orbits it and that Lucy will also be able to observe, Spaceflight Now report(opens in new tab)s.
Lucy's third target is an asteroid called Polymele, a gourd-shaped space rock that's roughly 13 miles (21 kilometers) from end to end. Polymele's shape is strange for an asteroid, suggesting that it's a remnant from the very early solar system — one that has managed to avoid collisions so far.
In March, astronomers observing Polymele in preparation for Lucy's eventual visit watched the asteroid pass in front of a star, blocking that star's distant light. In the process, they found something very curious: a tiny companion space rock.
"We got a really nice projected shape of Polymele, and then we were very surprised to detect an object about 200 kilometers (120 miles) away from Polymele," Hal Levison, a planetary scientist at the Southwest Research Institute and Lucy's principal investigator, said in a presentation last week, according to Spaceflight Now(opens in new tab). "It's 5 kilometers (3 miles) in diameter, and it's sitting almost exactly in Polymele's equatorial plane."
That companion does not have a name and won't have one until scientists know more about the asteroid's exact orbit, which might not happen until Lucy's visit. But some astronomers have jokingly begun calling it Shaun after the character in the animation "Shaun the Sheep."
Shaun is the second space rock to be added to the Lucy mission's itinerary: In 2020, scientists working on the mission determined that target asteroid Eurybates also boasts a small companion.
