30.09.2021
NASA’s Lucy Mission Prepares for Launch to Trojan Asteroids
NASA has tested the functions of Lucy, the agency’s first spacecraft to study Jupiter’s Trojan asteroids, filled it with fuel, and is preparing to pack it into a capsule for launch Saturday, Oct. 16.
Named after characters in Greek mythology, these asteroids circle the Sun in two swarms, with one group leading ahead of Jupiter in its path, the other trailing behind it. Lucy will be the first spacecraft to visit these asteroids. By studying these asteroids up close, scientists hope to hone their theories on how our solar system’s planets formed 4.5 billion years ago and why they ended up in their current configuration.
“With Lucy, we’re going to eight never-before-seen asteroids in 12 years with a single spacecraft,” said Tom Statler, Lucy project scientist at NASA Headquarters in Washington. “This is a fantastic opportunity for discovery as we probe into our solar system’s distant past.”
Following all pandemic protocols, Lucy team members have spent the past eight weeks at NASA’s Kennedy Space Center in Florida, preparing the spacecraft for flight. Engineers have tested the spacecraft’s mechanical, electrical, and thermal systems and practiced executing the launch sequence from the mission operations centers at Kennedy and Lockheed Martin Space in Littleton, Colorado. In early August, engineers installed the spacecraft’s high-gain antenna, its second most prominent feature after the expansive solar arrays, which will allow the spacecraft to communicate with Earth.
“There has been a lot of hands-on work,” said Donya Douglas-Bradshaw, Lucy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This summer has gone by so fast; it’s hard to believe we’re nearly at launch.”
On Sept. 18, propulsion engineers finished filling Lucy’s fuel tanks with approximately 1,600 pounds (725 kilograms) of liquid hydrazine and liquid oxygen, which make up 40% of the mass of the spacecraft. The fuel will be used for precise maneuvers that will propel Lucy to its asteroid destinations on schedule, while the solar arrays – each the width of a school bus – will recharge the batteries that will power spacecraft instruments.
The Lucy spacecraft will soon be packed into the two halves of the launch vehicle fairing, which will close around it like a clamshell. After the spacecraft is encapsulated, the Lucy team will be able to communicate with it electrically through an “umbilical cord.”
“Launching a spacecraft is almost like sending a child off to college – you’ve done what can for them to get them ready for that next big step on their own,” said Hal Levison, the principal investigator of the Lucy mission, based at the Southwest Research Institute in Boulder, Colorado.
In early October, the encapsulated spacecraft will be transported to the Vehicle Integration Facility at the Cape Canaveral Space Force Station, where it will be “mated” with the United Launch Alliance Atlas V 401 rocket. The Atlas V will lift off from Space Launch Complex 41.The rocket will carry Lucy outside Earth’s atmosphere to begin the long journey to the Trojan asteroids.
A few days prior to launch, engineers will power up the Lucy spacecraft in preparation for the mission. This process will take about 20 minutes.
“The spacecraft will sit in launch configuration and the engineering team will continuously monitor its health and status to make sure Lucy is ready to go,” said Jessica Lounsbury, the Lucy project systems engineer at Goddard. “And then it’s launch day.”
Lucy’s first launch attempt is scheduled for 5:34 a.m. EDT on Oct. 16. That day, the team will be “called to stations” at 1 a.m., which is when everyone is expected to arrive at mission control and other stations to monitor the spacecraft and run through the full launch countdown procedures. If weather or any other issues prohibit a launch that day, the team will have additional launch opportunities beginning the following day.
Southwest Research Institute in Boulder, Colorado, is the home institution of the principal investigator for the Lucy mission. Goddard 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 agency’s Science Mission Directorate in Washington. The launch is managed by NASA’s Launch Services Program based at Kennedy.
Quelle: NASA
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NASA's Lucy science mission will fly by eight asteroids
NASA plans to launch its Lucy spacecraft from Florida on Oct. 16 to fly by eight asteroids starting in 2025, marking the first time scientists will gain close-up views of them.
The spacecraft for the $981 million mission is at Kennedy Space Center for launch preparations, which include packing atop an Atlas V rocket for its 12-year voyage. United Launch Alliance plans to send the probe into space from adjacent Cape Canaveral Space Force Station.
Lucy will pass by a single asteroid in 2025 on its way to Jupiter's orbit, where its complex trajectory will take it by seven more asteroids in the so-called Trojan Belt.
The trip will be the first time any spacecraft has visited the Trojan asteroids, Lori Glaze, director of NASA's Planetary Science Division, said Tuesday during an online press conference.
"By studying the Trojan asteroids, we can gain more insight into the history of the outer solar system and the giant planets Jupiter, Saturn, Uranus and Neptune," Glaze said.
The Trojans are debris left from the formation of those planets, and NASA believes they haven't changed since the dawn of the solar system's planets, she said.
The spacecraft is about 43 feet long and has two very large disc-like solar arrays about 24 feet in diameter. More than 500 engineers and technicians built it at Lockheed Martin's plant in Littleton, Colo., where they assembled more than 430 components and more than 2 miles over wire, said Rich Lipe, the Lockheed Martin spacecraft program manager.
The large solar arrays are needed because Lucy will spend more than a decade so far from the sun. According to NASA, the solar arrays must open flawlessly soon after launch to provide Lucy with the power supply it will need.
After spending years to reach the asteroids, Lucy will attempt to fly within 600 miles of them, said Keith Noll, a NASA planetary astronomer and Lucy project scientist. The spacecraft will scan the rocky space objects with three instruments.
"Lucy doesn't slow down. It will be moving anywhere between 3 and 5 miles per second relative to the asteroids," Noll said. "The very best data will be collected in just a few hours during the closest approach."
The mission takes its name from the fossilized human skeleton found in Africa in 1974 that provided unique insight into humanity's evolution, according to NASA. The skeleton was named Lucy because teams of excavators at the discovery site routinely played the Beatles tune Lucy in the Sky with Diamonds.
Like the skeleton, the Lucy mission is geared to revolutionize knowledge of the past and formation of the solar system, according to NASA's mission profile.
Scientists will pore over Lucy's data for decades, said Hal Levison, a planetary scientist and a principal investigator on the mission, who is with the non-profit Southwest Research Institute based in San Antonio.
"The asteroids chosen for this are very physically different from one another," Levison said. "For example they have very different colors." He said that diversity should ensure that Lucy obtains a range of information about the Trojan asteroids.
Quelle: UPI
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Update: 8.10.2021
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NASA’s Lucy asteroid mission 10 days from launch
Fueled up for a 12-year mission of exploration, NASA’s Lucy science probe is nearly ready for launch Oct. 16 from Florida’s Space Coast to begin a journey through the solar system to visit eight asteroids, a record number for a single spacecraft.
Ground teams completed testing of the Lucy spacecraft last month inside a climate-controlled clean room at the Astrotech payload processing facility in Titusville, Florida, a few miles from the gates to NASA’s Kennedy Space Center.
The tests capped a two-month campaign at Astrotech since the Lucy spacecraft arrived from its Lockheed Martin factory in Colorado. Technicians loaded hydrazine and nitrogen tetroxide propellants into the probe to feed its small maneuvering thrusters and main engine, which will help steer Lucy toward its asteroid targets.
“Lucy is done, and we’re ready to fly,” said Hal Levison, the mission’s principal investigator from the Southwest Research Institute, or SWRI, in Boulder, Colorado.
The $981 million mission will be the first to explore a population of asteroids called the Trojans, which orbit the sun ahead of and behind Jupiter.
Scientists believe the Trojan asteroids represent a diverse sample of the types of small planetary building blocks left behind after the solar system formed 4.5 billion years ago. Lucy will fly by eight different asteroids from 2025 through 2033, including seven in the Trojan swarms.
The 3,300-pound (1,500-kilogram) Lucy spacecraft is scheduled for launch aboard an Atlas 5 rocket Oct. 16 during a 75-minute window opening at 5:34 a.m. EDT (0834 GMT). The mission has 23 days to blast off and take advantage of a unique alignment between Earth and the asteroids in the outer solar system.
If something prevents launch this year, NASA has a backup opportunity to launch Lucy in October 2022 without any impact to the mission’s science goals.
But the launch campaign has run smoothly in Florida, and officials overcame hurdles associated with the COVID-19 pandemic to keep Lucy on schedule.
“The pandemic hit us a really inopportune time,” said Arlin Bartels, Lucy’s deputy project manager at NASA’s Goddard Space Flight Center. “It hit right when the instrument teams were just getting into their fabrication and into their testing.
“Over 400 components go into the spacecraft. We were still in the supply chain phase at that point. Planetary launch periods are very unforgiving in the best of circumstances because everything has to come and hit per schedule,” Bartels said. “Trying to do that during a pandemic like this is a very daunting situation, and I’m not sure that everyone, when the pandemic hit, thought we would be able to see this through on time.”
But engineers finished assembling the spacecraft, attached its three science instruments, completed construction of the probe’s fan-shaped solar arrays, and put Lucy through a battery of tests to ensure it will survive the rigors of launch and deep space operations.
“We’re not working anything on the spacecraft or the launch vehicle that concerns any of us at this moment,” said Omar Baez, NASA’s launch director for the Lucy mission.
Last Friday, United Launch Alliance completed a countdown dress rehearsal at Cape Canaveral. The launch team loaded kerosene, liquid hydrogen, and liquid oxygen propellants into the Lucy mission’s Atlas 5 rocket, verifying the launch vehicle and ground systems are ready for the real countdown.
“We came out of that test Friday evening in good shape, so the vehicle is ready to accept the encapsulated Lucy spacecraft,” Baez said in an interview with Spaceflight Now. “So we’re ready to go.”
While ULA tested the Atlas 5 rocket last week, workers in the Astrotech payload processing facility encapsulated the Lucy spacecraft inside the Atlas 5’s nose shroud. The aerodynamic fairing will shield the probe during final pre-launch preps, and protect the craft during the first few minutes of the climb into space.
The 13.8-foot-diameter (4.2-meter) payload fairing, produced by ULA in Harlingen, Texas, is emblazoned with the Lucy mission logo. The insignia features a pictorial illustration of the fossilized remains of a human ancestor, called Lucy by the scientists who discovered her in Ethiopia in 1974.
The Lucy skeleton became the namesake for the Lucy asteroid mission.
Like the fossil discovery informed scientists about human evolution, the Trojan asteroids could provide clues about the solar system’s ancient history. After Jupiter formed and settled into its current orbit, the asteroids became trapped in swarms, each centered on a gravitationally-stable libration point ahead of and behind the solar system’s biggest planet.
Lucy, the fossil, received its name after scientists heard the Beatles song “Lucy In The Sky With Diamonds” while celebrating the discovery. Scientists developing the Trojan asteroid explorer saw the connection.
“These asteroids really are like diamonds in the sky in terms of their scientific value for understanding how the giant planets formed and the solar system evolved,” Levison said.
“That fossil transformed our understanding of hominid evolution, just like we hope that the Lucy spacecraft will transform our understanding of solar system,” said Cathy Olkin, mission’s deputy principal investigator from SWRI.
NASA selected the Lucy mission, along with another asteroid explore named Psyche, for development in 2017. Psyche is scheduled to launch next year to orbit a metal-rich asteroid.
Researchers believe the Trojan asteroids are the leftovers from the earliest period of the solar system’s history, when similar small objects clumped together to form the gas and ice planets of the outer solar system.
“If all this story is true, and Lucy is going to test some of these hypotheses, these objects really do represent objects that formed throughout the outer solar system, and are now in the Trojan swarms, where a mission like Lucy can go and study them,” Levison said.
Scientists know little about the Trojan asteroids. Lucy will be the first spacecraft to ever fly through the Trojan swarms, where researchers have found more than 7,000 small objects. There may be thousands more awaiting discovery using large telescopes.
But even the Hubble Space Telescope can’t resolve details about the composition and appearance of the Trojan asteroids. Scientists have a rough approximation of the size of each object to be visited by Lucy, and know a bit about their colors. Some are gray, and some are more reddish in appearance.
After blasting off from Cape Canaveral, the Lucy spacecraft will spend a year in an orbit around the sun similar to Earth’s, before returning to its home planet next October for a gravity assist slingshot maneuver to begin heading out into the solar system.
A second flyby of Earth in December 2024 will send Lucy toward its first asteroid encounter. The spacecraft will speed past asteroid Donaldjohanson, named for the scientist who discovered the Lucy fossil, in April 2025.
Then Lucy will fly into the first Trojan swarm, visiting five asteroids — including a tiny moon of one of the objects — in just 15 months between August 2027 and November 2028.
At its most distant arc, Lucy will be more than 500 million miles (800 million kilometers) from the sun. The spacecraft will be the farthest spacecraft from the sun to ever rely on solar power.
A final swing by Earth in 2030 will set up Lucy for the last encounter of the 12-year mission, a flyby of a binary pair of asteroids named Patroclus and Menoetius in March 2033. Each of the two objects are about the same size, with diameters of more than 60 miles (100 kilometers), making them the largest targets of Lucy’s solar system sojourn.
At each asteroid, Lucy will have just hours to take the best pictures and gather the most useful data. The probe will zip by the asteroids at a relative velocity of several miles per second, using a gimbaling instrument platform to point its camera and science instruments.
“Lucy is a flyby mission, so after spending years traveling more than a billion miles to get to our targets, we aim almost directly at them, flying within 600 miles (1,000 kilometers) of their surfaces,” said Keith Noll, NASA’s project scientist for the Lucy mission. “And Lucy doesn’t slow down for these flybys.”
Quelle: SN
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Update: 15.10.2021
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Lucy Mission Set to Launch to Study Trojan Asteroids
With the Lucy spacecraft aboard, a United Launch Alliance Atlas V rocket is seen as it is rolled out of the Vertical Integration Facility to the launch pad at Space Launch Complex 41, Thursday, Oct. 14, 2021, at Cape Canaveral Space Force Station in Florida. Lucy will be the first spacecraft to study Jupiter's Trojan asteroids. Like the mission's namesake – the fossilized human ancestor, "Lucy," whose skeleton provided unique insight into humanity's evolution – Lucy will revolutionize our knowledge of planetary origins and the formation of the solar system.
The Lucy mission is slated to launch on Saturday, Oct. 16, 2021, at 5:43 a.m. EDT. Launch coverage begins on NASA TV at 5 a.m.
Quelle: NASA
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