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Quasars are the light fantastic. They are the brightest beacons in the universe, blazing across space with the intrinsic brightness of one trillion suns. Yet the objects are not vast galaxies, but they appear as pinpoint sources in the biggest telescopes of today – hence the term "quasar" for quasi-stellar object. Discovered in the 1960s, it took more than two decades of research to come to the conclusion that quasars are produced by the gusher of energy coming from over-fed supermassive black holes inside the cores of very distant galaxies. And, most quasars bloomed into a brief existence 12 billion years ago.

The big question has been, why? What was happening in the universe 12 billion years ago? The universe was smaller and so crowded that galaxies collided with each other much more frequently than today. Astronomers using Hubble's near-infrared vision tested this hypothesis by looking at dusty quasars where their glow was suppressed by dust, allowing a view of the quasar's surroundings. Hubble's sharp vision revealed chaotic collisions between galaxies that gave birth to quasars by fueling a supermassive central black hole.

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    • By NASA
      On Jan. 19, 1965, Gemini 2 successfully completed the second of two uncrewed test flights of the spacecraft and its Titan II booster, clearing the way for the first crewed mission. The 18-minute suborbital mission achieved the primary goals of flight qualifying the Gemini spacecraft, especially its heat shield during a stressful reentry. Recovery forces retrieved the capsule following its splashdown, allowing engineers to evaluate how its systems fared during the flight. The success of Gemini 2 enabled the first crewed mission to fly two months later, beginning a series of 10 flights over the following 20 months. The astronauts who flew these missions demonstrated the rendezvous and docking techniques necessary to implement the Lunar Orbit Rendezvous method NASA chose for the Moon landing mission. They also proved that astronauts could work outside their spacecraft during spacewalks and that spacecraft and astronauts could function for at least eight days, the minimum time for a roundtrip lunar mission. The Gemini program proved critical to fulfill President John F. Kennedy’s goal of landing a man on the Moon and returning him safely to Earth before the end of the 1960s. 
      Cutaway diagram of the Gemini spacecraft. Workers at Launch Pad 19 lift Gemini 2 to mate it with its Titan II rocket. At Pad 19, engineers verify the flight simulators inside Gemini 2. Following the success of Gemini 1 in April 1964, NASA had hoped to fly the second mission before the end of the year and the first crewed mission by January 1965. The two stages of the Titan II rocket arrived at Cape Kennedy from the Martin Marietta factory in Baltimore on July 11, and workers erected it on Launch Pad 19 five days later. A lightning strike at the pad on Aug. 17 invalidated all previous testing and required replacement of some pad equipment. A series of three hurricanes in August and September forced workers to partially or totally unstack the vehicle before stacking it for the final time on Sept. 14. The Gemini 2 spacecraft arrived at Cape Kennedy from its builder, the McDonnell Company in St. Louis, on Sept. 21, and workers hoisted it to the top of the Titan II on Oct. 18. Technical issues delayed the spacecraft’s physical mating to the rocket until Nov. 5. These accumulated delays pushed the launch date back to Dec. 9. 

      The launch abort on Dec. 9, 1964. Liftoff of Gemini 2 from Launch Pad 19 on Jan. 19, 1965. Engineers in the blockhouse monitor the progress of the Titan II during the ascent. Fueling of the rocket began late on Dec. 8, and following three brief holds in the countdown, the Titan’s two first stage engines ignited at 11:41 a.m. EST on Dec. 9. and promptly shut down one second later. Engineers later determined that a cracked valve resulted in loss of hydraulic pressure, causing the malfunction detection system to switch to its backup mode, forcing a shutdown of the engines. Repairs meant a delay into the new year. On Jan. 19, 1965, following a mostly smooth countdown, Gemini 2 lifted off from Pad 19 at 9:04 a.m. EST. 

      The Mission Control Center (MCC) at NASA’s Kennedy Space Center in Florida. In the MCC, astronauts Eugene Cernan, left, Walter Schirra, Gordon Cooper, Donald “Deke” Slayton, and Virgil “Gus” Grissom monitor the Gemini 2 flight. In the Gemini Mission Control Center at NASA’s Kennedy Space Center in Florida, Flight Director Christopher C. Kraft led a team of flight controllers that monitored all aspects of the flight. At the Manned Spacecraft Center (MSC), now NASA’s Johnson Space Center in Houston, a team of controllers led by Flight Director John Hodge passively monitored the flight from the newly built Mission Control Center. They would act as observers for this flight and Gemini 3, the first crewed mission, before taking over full control with Gemini IV, and control all subsequent American human spaceflights. The Titan rocket’s two stages placed Gemini 2 into a suborbital trajectory, reaching a maximum altitude of 98.9 miles, with the vehicle attaining a maximum velocity of 16,709 miles per hour. Within a minute after separating from the Titan’s second stage, Gemini 2 executed a maneuver to orient its heat shield in the direction of flight to prepare for reentry. Flight simulators installed where the astronauts normally would sit controlled the maneuvers. About seven minutes after liftoff, Gemini 2 jettisoned its equipment section, followed by firing of the retrorockets, and then separation of the retrorocket section, exposing the spacecraft’s heat shield. 

      View from a camera mounted on a cockpit window during Gemini 2’s reentry. View from the cockpit window during Gemini 2’s descent on its parachute. Gemini 2 then began its reentry, the heat shield protecting the spacecraft from the 2,000-degree heat generated by friction with the Earth’s upper atmosphere. A pilot parachute pulled away the rendezvous and recovery section. At 10,000 feet, the main parachute deployed, and Gemini 2 descended to a splashdown 2,127 miles from its launch pad, after a flight of 18 minutes 16 seconds. The splashdown took place in the Atlantic Ocean about 800 miles east of San Juan, Puerto Rico, and 25 miles from the prime recovery ship, the U.S.S. Lake Champlain (CVS-39). 

      A U.S. Navy helicopter hovers over the Gemini 2 capsule following its splashdown as a diver jumps into the water. Sailors hoist Gemini 2 aboard the U.S.S. Lake Champlain. U.S. Navy helicopters delivered divers to the splashdown area, who installed a flotation collar around the spacecraft. The Lake Champlain pulled alongside, and sailors hoisted the capsule onto the carrier, securing it on deck one hour forty minutes after liftoff. The spacecraft appeared to be in good condition and arrived back at Cape Kennedy on Jan. 22 for a thorough inspection. As an added bonus, sailors recovered the rendezvous and recovery section. Astronaut Virgil “Gus” Grissom, whom along with John Young NASA had selected to fly the first crewed Gemini mission, said after the splashdown, “We now see the road clear to our flight, and we’re looking forward to it.” Flight Director Kraft called it “very successful.” Gemini Program Manager Charles Matthews predicted the first crewed mission could occur within three months. Gemini 3 actually launched on March 23. 
      Enjoy this NASA video of the Gemini 2 mission. 
      Postscript 
      The Gemini-B capsule and a Manned Orbiting Laboratory (MOL) mockup atop a Titan-IIIC rocket in 1966. The flown Gemini-B capsule on display at the Cape Canaveral Space Force Museum in Florida. Former MOL and NASA astronaut Robert Crippen stands beside the only flown Gemini-B capsule – note the hatch in the heat shield at top. Gemini 2 not only cleared the way for the first crewed Gemini mission and the rest of the program, it also took on a second life as a test vehicle for the U.S. Air Force’s Manned Orbiting Laboratory (MOL). The Air Force modified the spacecraft, including cutting a hatch through its heat shield, renamed it Gemini-B, and launched it on Nov. 3, 1966, atop a Titan IIIC rocket. The test flight successfully demonstrated the hatch in the heat shield design during the capsule’s reentry after a 33-minute suborbital flight. Recovery forces retrieved the Gemini-B capsule in the South Atlantic Ocean and returned it to the Air Force for postflight inspection. This marked the only repeat flight of an American spacecraft intended for human spaceflight until the advent of the space shuttle. Visitors can view Gemini 2/Gemini-B on display at the Cape Canaveral Space Force Museum.  
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    • By NASA
      On Jan. 17, 1990, NASA announced the selection of its 13th group of astronaut candidates. The diverse group comprised 23 candidates – seven pilots and 16 mission specialists. The group included one African American, one Asian American, and five women including the first female pilot and the first Hispanic woman. Following one year of astronaut candidate training, all 23 became eligible for technical assignments within the astronaut office and for assignment to space shuttle crews. All members of the group completed at least one spaceflight, making significant contributions to the space shuttle program, the Shuttle Mir program, important science missions, and assembly and maintenance of the International Space Station. Several went on to serve in key NASA management positions. 
      The Group 13 NASA astronaut candidates pose for a group photo – front row kneeling, Charles Precourt, left, Janice Voss, Ellen Ochoa, David Wolf, Eileen Collins, and Daniel Bursch; standing, William Gregory, left, Jeffrey Wisoff, Carl Walz, Richard Searfoss, Donald Thomas, James Halsell, Thomas Jones, James Newman, Kenneth Cockrell, Bernard Harris, Leroy Chiao, Ronald Sega, Susan Helms, William McArthur, Nancy Sherlock, Richard Clifford, and Terrance Wilcutt. The newest class of NASA astronaut candidates included pilot candidates Kenneth Cockrell, Eileen Collins, William Gregory, James Halsell, Charles Precourt, Richard Searfoss, and Terrence Wilcutt and mission specialist candidates Daniel Bursch, Leroy Chiao, Rich Clifford, Bernard Harris, Susan Helms, Thomas Jones, William Mc Arthur, James Newman, Ellen Ochoa, Ronald Sega, Nancy Sherlock, Donald Thomas, Janice Voss, Carl Walz, Jeffrey Wisoff, and David Wolf. From the 1,945 qualified applicants, NASA invited 103 candidates for interviews and medical exams at NASA’s Johnson Space Center (JSC) in Houston between September and November 1989. 
      Group 13 astronaut candidates Bernard Harris, left, Susan Helms, and William McArthur during wilderness survival training. Group 13 astronaut candidates William Gregory, left, and Susan Helms during water survival training. Group 13 astronaut candidate Eileen Collins listens to a lecture on parachute ejection. The 23 astronaut candidates reported to work at JSC on July 16, 1990, to begin their one-year training period. During the yearlong training, the candidates attended classes in applied sciences, space shuttle systems, space medicine, Earth and planetary sciences, and materials sciences. They visited each of the NASA centers to learn about their functions and received instruction in flying the T-38 Talon training aircraft, high-altitude and ground egress systems, survival skills, parasail flight, and scuba. They experienced short-duration weightlessness aboard NASA’s KC-135 aircraft dubbed the Vomit Comet. After completing the astronaut candidate training, they qualified for various technical assignments within the astronaut office leading to assignments to space shuttle crews. 
      The Group 13 patch. Group 13 NASA astronaut Daniel Bursch Group 13 NASA astronaut Leroy Chiao Group 13 NASA astronaut Rich Clifford. Per tradition, most astronaut classes have a nickname, often humorously given to them by the previous class of astronauts. In the case of the class of 1990, they chose their own nickname, The Hairballs. The origin stems from the class adopting a black cat as their mascot, in recognition of their class number 13. The nickname came about as hairballs are often associated with cats. 
      Daniel Bursch 
      Born in Pennsylvania, Bursch grew up in New York state and graduated from the U.S. Naval Academy. He served as a pilot in the U.S. Navy prior to his selection as an astronaut. He received his first flight assignment as a mission specialist on STS-51, flying with fellow Hairballs Newman and Walz on the 10-day flight aboard Discovery in 1993. On his second mission, the 10-day STS-68 flight aboard Endeavour in 1994, Bursch, accompanied by fellow classmates Jones, Wilcutt, and Wisoff, served as a mission specialist on the Space Radar Laboratory-2 (SRL-2) Earth observation mission. For his third trip into space, Bursch flew as a mission specialist aboard Endeavour for the 10-day STS-77 mission in 1996. For his fourth and final spaceflight, Bursch, along with fellow Hairball Walz, spent 196 days in space as an Expedition 4 flight engineer aboard the space station in 2001 and 2002, conducting two spacewalks totaling 11 hours 46 minutes. He launched on STS-108 and returned on STS-111. Across his four missions, Bursch accumulated 227 days in space. 
      Leroy Chiao 
      California native Chiao earned a doctorate in chemical engineering from the University of California, Santa Barbara, before NASA selected him as an astronaut. For his first flight, he flew as a mission specialist on STS-65, the International Microgravity Lab-2 (IML-2) mission aboard Columbia in 1994. Fellow Hairballs Halsell, Walz, and Thomas accompanied Chiao on the nearly 15-day flight, the longest shuttle mission up to that time. During his second spaceflight, the nine-day STS-72 flight of Endeavour in 1996, Chiao participated in two spacewalks totaling 13 hours 3 minutes to demonstrate future techniques. In 2000, Chiao, accompanied by fellow classmates McArthur and Wisoff, flew the 13-day STS-92 3A space station assembly mission aboard Discovery. He participated in two spacewalks with classmate McArthur totaling 13 hours 16 minutes. For his fourth and final mission, Chiao served as commander of Expedition 10 in 2004 and 2005, spending 193 days in space. During the mission, he conducted two spacewalks totaling 9 hours 58 minutes. During his four flights, Chiao logged 229 days in space and spent more than 36 hours outside on his six spacewalks. 
      Rich Clifford 
      Clifford, born in California, grew up in Ogden, Utah. He holds the distinction as one of the first three astronauts of his class assigned to a spaceflight, the seven-day STS-53 mission aboard Discovery in 1992 to deploy a large satellite for the Department of Defense. His second flight, the SRL-1 mission aboard Endeavour took place in 1994. Fellow Hairball Jones accompanied him on the STS-59 11-day Earth observation mission. For his third and final spaceflight, Clifford flew as a mission specialist on the STS-76 third Shuttle Mir docking mission. During the nine-day mission in 1996, accompanied by fellow classmate Sega, Clifford participated in a six-hour one-minute spacewalk. During his three spaceflights, he accumulated nearly 28 days in space. 

      Group 13 NASA astronaut Kenneth Cockrell. Group 13 NASA astronaut Eileen Collins Group 13 NASA astronaut William Gregory. Group 13 NASA astronaut James Halsell. Kenneth Cockrell 
      Cockrell, a native Texan, served as naval aviator prior to his selection as an astronaut. On his first mission, STS-56, he served as a mission specialist for the nine-day ATLAS-2 Earth observation mission in 1993. Fellow classmate Ochoa accompanied him on the flight aboard Discovery. Cockrell served as pilot on his second mission, the 11-day STS-69 Endeavour flight in 1995 to deploy and retrieve the Wake Shield Facility. Classmate Voss accompanied him on this mission. Cockrell commanded his third spaceflight, STS-80 in 1996 aboard Columbia, accompanied by fellow Hairball Jones. At 17 days 15 hours 53 minutes days, it holds the distinction as the longest shuttle flight. He once again served as commander on his fourth mission, the STS-98 5A space station assembly flight in 2001. Accompanied by classmate Jones, the crew delivered the U.S. Laboratory Module Destiny during the 13-day mission. On his fifth and final spaceflight, Cockrell commanded the STS-111 space station UF-2 utilization mission in 2002. During the 14-day flight, the crew brought the Expedition 5 crew to the station and returned the Expedition 4 crew, including Hairballs Bursch and Walz. During his five missions, Cockrell accumulated 64.5 days in space. He served as Chief of the Astronaut Office from October 1997 to October 1998. 
      Eileen Collins 
      Hailing from New York state, Collins has the distinction as the first female selected by NASA as a shuttle pilot. She received her first flight assignment as pilot of STS-63, the eight-day Shuttle-Mir rendezvous mission in 1995. Fellow classmates Harris and Voss accompanied her aboard Discovery. Collins once again served as pilot on STS-84, the sixth Shuttle-Mir docking mission commanded by fellow Hairball Precourt. The nine-day flight aboard Atlantis took place in 1997. On her third flight, Collins served as the first female commander of a space mission, the five-day STS-93 flight of Columbia in 1999 to deploy the Chandra X-ray Observatory. She commanded her fourth and final mission, the STS-114 return to flight mission following the Columbia accident. The 14-day flight aboard Discovery took place in 2005. During her four missions, Collins logged 36 days in space. 
      William Gregory 
      New York native Gregory served as a U.S. Air Force pilot when NASA selected him as an astronaut. He flew his single mission as pilot of STS-67, the 17-day Astro-2 mission aboard Endeavour in 1995. The mission set a record for the longest shuttle flight up to that time. 
      James Halsell 
      Halsell, a native of Louisiana, served as a U.S. Air Force pilot when NASA selected him as an astronaut. On his first spaceflight, he served as pilot on STS-65, the IML-2 mission aboard Columbia in 1994. Fellow Hairballs Chiao, Walz, and Thomas accompanied Halsell on the nearly 15-day flight, the longest shuttle mission up to that time. Halsell once again served as pilot on his second flight, STS-74, the second Shuttle-Mir docking mission that delivered the Docking Module to Mir. Classmate McArthur joined Halsell on the eight-day Atlantis flight in 1995. He commanded his third spaceflight, STS-83 aboard Columbia, the Microgravity Sciences Lab in 1997. Because managers cut the flight short after four days due to a fuel cell failure, NASA decided to refly the mission, with the same crew, later in the year as STS-94, and it stayed in space for nearly 16 days. Classmates Voss and Thomas accompanied Halsell on both missions. Halsell also commanded his fifth and final spaceflight, the STS-101 2A.2a space station logistics mission in 2000. Classmate Helms accompanied Halsell on the 10-day mission aboard Atlantis. During his five missions, Halsell accumulated more than 52 days of spaceflight time.  

      Group 13 NASA astronauts Bernard Harris Group 13 NASA astronaut Susan Helms. Group 13 NASA astronaut Thomas Jones. Group 13 NASA astronaut William McArthur. Bernard Harris 
      Texas native Harris served as a NASA flight surgeon when the agency selected him as an astronaut. He holds the distinction as one of the first three astronauts of his class assigned to a spaceflight. He served as a mission specialist on the STS-55 joint U.S.-German Spacelab D2 mission in 1993. Fellow Hairball Precourt accompanied him on the 10-day flight aboard Columbia. Harris flew as payload commander on his second and final spaceflight, the STS-63 Mir rendezvous mission in 1995, accompanied by classmates Collins and Voss. During the flight, Harris conducted a 4-hour 49-minute spacewalk, earning the distinction as the first African American to do so. Across his two missions, Harris logged 18 days in space. 
      Susan Helms 
      Helms, a native of Portland, Oregon, graduated from the U.S. Air Force Academy in the first class that included women. Shortly after her selection as an astronaut, NASA assigned her to her first spaceflight, and she holds the distinction as one of the first three astronauts of her class assigned to a mission. She flew as a mission specialist on STS-54, a six-day flight aboard Endeavour in 1993 that deployed the sixth Tracking and Data Relay Satellite. On her second mission, Helms flew aboard STS-64, an 11-day flight aboard Discovery in 1994. She served as the payload commander on STS-78, the Life and Microgravity Sciences Spacelab mission aboard Columbia in 1996. The flight set a then-record of 16 days 22 hours for the longest space shuttle mission. On her fourth mission, she served as a mission specialist on STS-101, the 2A.2a space station logistics mission in 2000 commanded by classmate Halsell. The Atlantis mission lasted 10 days. For her fifth and final spaceflight, she served as a flight engineer during Expedition 2, the first woman to fly a long-duration mission on the International Space Station. She conducted one spacewalk lasting 8 hours 56 minutes, a record not broken until 2024. During her five spaceflights she logged 211 days in space. 
      Thomas Jones 
      Jones, a native of Baltimore, graduated from the U.S. Air Force Academy and served as a B-52 pilot when NASA selected him as an astronaut. For his first spaceflight, he served as a mission specialist on STS-59, the 11-day SRL-1 Earth observation mission on Endeavour in 1994, along with classmate Clifford. Later that same year, with just 163 days between the two missions – the second shortest turnaround time in history – Jones served as payload commander on STS-68, the 11-day SRL-2 mission also on Endeavour. Fellow Hairballs Wilcutt, Wisoff, and Bursch accompanied him on the mission. In 1996, Jones flew as a mission specialist on STS-80, commanded by classmate Cockrell. During the nearly 18-day flight – the longest shuttle flight in history – Jones had planned to participate in two spacewalks, but a stuck bolt prevented the opening of Columbia’s airlock hatch, forcing the cancelation of the excursions. Jones flew his fourth and final mission in 2001, the STS-98 5A space station assembly flight, commanded by classmate Cockrell. During the 13-day mission of Atlantis, the crew installed the U.S. Laboratory Module Destiny and Jones participated in three spacewalks totaling nearly 20 hours. During his four spaceflights, Jones logged 53 days in space. 
      William McArthur 
      Hailing from North Carolina, West Point graduate McArthur worked as a space shuttle vehicle integration test engineer at JSC when NASA selected him as an astronaut. He received his first spaceflight assignment as a mission specialist on the STS-58 Spacelab Life Sciences-2 (SLS-2) mission in 1993. Classmates Searfoss and Wolf accompanied him on the 14-day Columbia mission, at the time the longest space shuttle flight. In 1995, he flew as a mission specialist on STS-74, the second Shuttle Mir docking mission that brought the Docking Module to Mir. Classmate Halsell served as pilot on the eight-day flight of Atlantis. McArthur next flew on STS-92, the 3A space station assembly mission in 2000, accompanied by classmates Chiao and Wisoff. McArthur completed two spacewalks with Chiao totaling 13 hours 16 minutes during the 13-day Atlantis mission. For his fourth and final spaceflight, McArthur served as commander of the 190-day Expedition 12 in 2005-2006, conducting two spacewalks totaling 11 hours 5 minutes. During his four missions, McArthur logged 225 days in space and spent more than 24 hours on four spacewalks. He served as the director of the JSC Safety and Mission Assurance Directorate from 2011 to 2017. 

      Group 13 NASA astronaut James Newman. Group 13 NASA astronaut Ellen Ochoa. Group 13 NASA astronaut Charles Precourt. Group 13 NASA astronaut Richard Searfoss. James Newman 
      Born in Micronesia, Newman grew up in San Diego and earned a doctorate in physics from Rice University. He worked at JSC as a crew and flight controller trainer when NASA selected him as an astronaut. For his first spaceflight assignment, Newman flew as a mission specialist on STS-51 in 1993 with fellow Hairballs Bursch and Walz. During the 10-day mission aboard Discovery, Newman conducted a 7-hour 5-minute spacewalk with Walz to demonstrate future spacewalking techniques. His second flight took place in 1995, the 11-day STS-69 mission of Endeavour, with classmate Halsell serving as pilot. On his third mission, Newman flew as a mission specialist on STS-88, the first space station assembly flight in 1998. Classmate Sherlock, now using her married name Currie, accompanied him on the 12-day Atlantis mission. Newman participated in three spacewalks totaling 21 hours 22 minutes. For his fourth and final spaceflight in 2002, Newman flew on STS-109, the fourth servicing mission to the Hubble Space Telescope, accompanied once again by classmate Currie. During the 11-day Columbia mission, Newman conducted two spacewalks totaling 14 hours 46 minutes. During his career four spaceflights, Newman logged more than 43 days in space and spent nearly 50 hours on six spacewalks. 
      Ellen Ochoa 
      Born in Los Angeles, Ochoa received her doctorate in electrical engineering from Stanford University and worked at NASA’s Ames Research Center in California’s Silicon Valley when NASA selected her as an astronaut. Her first flight assignment came in 1993 when she flew as a mission specialist on STS-56, the nine-day ATLAS-2 Earth observation mission. Classmate Cockrell accompanied her on the Discovery mission. On her second spaceflight, she served as payload commander on the STS-66 ATLAS-3 mission, an 11-day flight of Atlantis in 1994. For her third flight, she flew on Discovery’s STS-96, the 10-day 2A.1 space station assembly and logistics mission in 1999. In 2002, on her fourth and final mission, STS-110, she served as a mission specialist on the 8A space station assembly flight that brought the S0 truss to the facility. The flight on Atlantis lasted nearly 11 days. Over her four missions, Ochoa accumulated nearly 41 days in space. Following her spaceflights, Ochoa served in management positions with increasing scope and responsibilities, as director of the Flight Crew Operations Directorate, JSC deputy director, and JSC director. 
      Charles Precourt 
      Massachusetts native Precourt graduated from the U.S. Air Force Academy and served as a U.S. Air Force pilot when NASA selected him as an astronaut. On his first spaceflight in 1993, he served as a mission specialist on STS-55, the joint U.S.-German Spacelab D2 mission. Fellow Hairball Harris accompanied him on the 10-day Columbia mission. On his next spaceflight, Precourt served as pilot on STS-71, the first Shuttle-Mir docking mission in 1995. The 10-day Atlantis mission included the first shuttle-based crew rotation. Precourt commanded his third spaceflight, STS-84 in 1987, the sixth Shuttle-Mir docking mission. Classmate Collins served as pilot on the nine-day Atlantis mission. He commanded his fourth and final space mission, STS-91, the ninth and final Shuttle-Mir docking flight, earning him the honor as the only American astronaut to visit Mir three times. The 10-day mission aboard Discovery took place in 1998. Across his four spaceflights, Precourt logged nearly 39 days in space. He served as chief of the Astronaut Office from October 1998 to November 2002. 
      Richard Searfoss 
      Born in Michigan, Searfoss graduated from the U.S. Air Force Academy and served as an instructor at the U.S. Air Force Test Pilot School when NASA selected him as an astronaut. On his first spaceflight, Searfoss served as pilot on STS-58, the SLS-2 mission in 1993. Classmates McArthur and Wolf joined him on the flight aboard Columbia, at 14 days then the longest space shuttle mission. In 1996, he once again served as pilot on STS-76, the third Shuttle-Mir docking mission. Classmates Clifford and Sega joined him on the nine-day flight aboard Atlantis. Searfoss commanded his third and final spaceflight, the 16-day STS-90 Neurolab mission aboard Columbia in 1998. Across his three missions, Searfoss logged 39 days in space. 

      Group 13 NASA astronaut Ronald Sega. Group 13 NASA astronaut Nancy Sherlock. Group 13 NASA astronaut Donald Thomas. Group 13 NASA astronaut Janice Voss. Ronald Sega 
      Ohio native Sega graduated from the U.S. Air Force Academy and worked as a research associate professor of physics at the University of Houston when NASA selected him as an astronaut. On his first spaceflight, he served as a mission specialist aboard STS-60, the first Shuttle-Mir mission. The eight-day mission aboard Discovery took place in 1994. For his second and final spaceflight in 1996, Sega served as a mission specialist on STS-76, the third Shuttle-Mir docking mission. Fellow Hairballs Searfoss and Clifford also flew on the nine-day Atlantis mission. Across his two spaceflights, Sega logged 17.5 days in space. 
      Nancy Sherlock Currie 
      Born in Delaware, Sherlock grew up in Ohio and worked as a flight simulation engineer at JSC when NASA selected her as an astronaut. On her debut spaceflight, Sherlock flew as a mission specialist on STS-57, the first flight of the Spacehab module in 1993. Fellow classmates Voss and Wisoff joined her on the 10-day mission aboard Endeavour. On her subsequent missions, she flew under her married name of Currie. Her second trip into space took place in 1995, the nine-day STS-70 mission aboard Discovery. Classmate Thomas joined her on this mission to deploy the seventh TDRS satellite. On her third mission, Currie flew as a mission specialist on STS-88, the first space station assembly mission in 1998. Classmate Newman accompanied her on the 12-day Atlantis mission. For her fourth and final spaceflight in 2002, Currie flew on STS-109, the fourth Hubble Space Telescope servicing mission. Classmate Newman once again accompanied her on the 11-day Columbia mission. Across her four spaceflights, Currie logged nearly 42 days in space. 
      Donald Thomas 
      Ohio native Thomas earned a doctorate in materials science from Cornell University and worked as a materials science engineer at JSC when NASA selected him as an astronaut. For his first flight, he flew as a mission specialist on STS-65, the IML-2 mission aboard Columbia in 1994. Fellow Hairballs Halsell, Chiao, and Walz accompanied Thomas on the nearly 15-day flight, the longest shuttle mission up to that time. His second trip into space took place in 1995, the nine-day STS-70 mission aboard Discovery. Classmate Currie joined him on this mission to deploy the seventh TDRS satellite. Thomas flew his third spaceflight on STS-83 aboard Columbia, the MSL mission in 1997. Because managers cut the flight short after four days due to a fuel cell failure, NASA decided to fly the mission again, with the same crew, later in the year as STS-94, for the full 16-day mission duration. Classmates Halsell and Voss accompanied Thomas on both missions. Across his four missions, Thomas logged 43 days in space. 
      Janice Voss 
      Ohio native Voss earned a doctorate in aeronautics and astronautics from the Massachusetts Institute of Technology and worked as an integration manager at Orbital Science Corporation in Houston when NASA selected her as an astronaut. On her first spaceflight, Voss flew as a mission specialist on STS-57, the first flight of the Spacehab module in 1993. Fellow classmates Sherlock and Wisoff joined her on the 10-day mission aboard Endeavour. Voss flew as a mission specialist on her second spaceflight, the STS-63 Mir rendezvous mission in 1995, accompanied by classmates Collins and Harris. Voss flew as payload commander on her third spaceflight on STS-83 aboard Columbia, the MSL mission in 1997. Because managers cut the flight short after four days due to a fuel cell failure, NASA decided to refly the mission, with the same crew, later in the year as STS-94, for the full 16-day mission duration. Classmates Halsell and Thomas accompanied Voss on both missions. On her fifth and final spaceflight, Voss once again served as payload commander on STS-99, the Shuttle Radar Topography Mission. The 11-day mission aboard Endeavour took place in 2000. Over her five missions, Voss accumulated 49 days of spaceflight time. 

      Group 13 NASA astronaut Carl Walz. Group 13 NASA astronaut Terrance Wilcutt. Group 13 NASA astronaut Jeff Wisoff. Group 13 NASA astronaut David Wolf. Carl Walz 
      A native of Ohio, Walz worked as a flight test manager at the U.S. Air Force Flight Test Center in Nevada when NASA selected him as an astronaut. He received his first flight assignment as a mission specialist on STS-51, flying with fellow Hairballs Bursch and Newman on the 10-day flight aboard Discovery in 1993. Walz conducted a 7-hour 5-minute spacewalk with Newman to demonstrate future spacewalking techniques. For his second flight, he flew as a mission specialist on STS-65, the IML-2 mission aboard Columbia in 1994. Fellow Hairballs Halsell, Chiao, and Thomas accompanied Walz on the nearly 15-day flight, the longest shuttle mission up to that time. On his third trip into space, he served as a mission specialist on STS-79, the fourth Shuttle-Mir docking mission in 1996. Classmate Wilcutt served as pilot on the 10-day Atlantis mission. For his fourth and final spaceflight, Walz, along with fellow Hairball Bursch, spent 196 days in space as an Expedition 4 flight engineer aboard the space station in 2001 and 2002, conducting two spacewalks totaling 11 hours 50 minutes. He launched on STS-108 and returned on STS-111. Across his four missions, Walz logged more than 230 days in space and spent nearly 19 hours on three spacewalks. 
      Terrance Wilcutt 
      A native of Kentucky, Wilcutt served in the U.S. Marine Corps and worked as a test pilot at Naval Air Station Patuxent River when NASA selected him as an astronaut. Wilcutt served as pilot on his first spaceflight, STS-68, the 10-day SRL-2 Earth observation mission aboard Endeavour in 1994. Classmates Bursch, Jones, and Wisoff accompanied Wilcutt on the flight. He served as pilot on his second spaceflight, the STS-79 fourth Shuttle-Mir docking mission in 1996. Fellow Hairball Walz accompanied him on the 10-day Atlantis mission. Wilcutt commanded his third mission, STS-89, the eighth Shuttle-Mir docking mission. The nine-day flight aboard Endeavour took place in 1998. He commanded his fourth and final spaceflight in 2000, the STS-106 2A.2b space station assembly and logistics mission. The 12-day mission flew on Atlantis. Across his four missions, Wilcutt logged 42 days in space. He served as the NASA chief of Safety and Mission Assurance from 2011 to 2020. 
      Jeff Wisoff 
      Virginia native Wisoff earned a doctorate in applied physics from Stanford University and worked as an assistant professor at Rice University when NASA selected him as an astronaut. On his first spaceflight, Wisoff flew as a mission specialist on STS-57, the first flight of the Spacehab module in 1993. Fellow classmates Sherlock and Voss joined him on the 10-day mission aboard Endeavour. He participated in a 5-hour 50-minute spacewalk to demonstrate future spacewalking techniques. Wisoff served as a mission specialist on his second spaceflight, STS-68, the 10-day SRL-2 Earth observation mission aboard Endeavour in 1994. Classmates Bursch, Jones, and Wilcutt accompanied him on the flight. He served as a mission specialist on his third flight, STS-81, the fifth Shuttle-Mir docking mission in 1997. The 10-day flight took place aboard Atlantis. He flew his fourth and final mission on STS-92, the 3A space station assembly mission in 2000 that brought the Z1 truss to the facility. Wisoff participated in two spacewalks totaling 14 hours 3 minutes during the 13-day Discovery mission. Across his four spaceflights, Wisoff logged 44 days in space and spent nearly 20 hours on three spacewalks. 
      David Wolf 
      A native of Indiana, Wolf earned a medical degree from Indiana University and worked as an aerospace medical officer at JSC when NASA selected him as an astronaut. He received his first spaceflight assignment as a mission specialist on the STS-58 SLS-2 mission in 1993. Classmates Searfoss and McArthur accompanied him on the 14-day Columbia mission, at the time the longest space shuttle flight. For his second trip into space, he completed the 128-day NASA-6 long-duration mission as part of the Shuttle-Mir program in 1997 and 1998, launching aboard STS-86 and returning aboard STS-89. He participated in a 3-hour 52-minute spacewalk. He flew his third spaceflight as a mission specialist on the STS-112 9A space station assembly mission in 2002 that delivered the S1 truss to the orbiting lab. During the 11-day Atlantis mission, Wolf participated in three spacewalks totaling 19 hours 41 minutes. He completed his fourth mission on STS-127 in 2009, earning him the distinction as the last Hairball to make a spaceflight. During the 16-day Endeavour mission that delivered the Japanese module’s exposed pallet to the space station, Wolf participated in three spacewalks totaling 18 hours 24 minutes. Across his four spaceflights, Wolf logged more than 168 days in space and spent 42 hours on seven spacewalks. 
      Summary
      The NASA Group 13 astronauts made significant contributions to spaceflight. As a group, they completed 85 flights spending 1,960 days, or more than five years, in space, including one long-duration flight aboard Mir and five aboard the International Space Station. One Hairball made a single trip into space, three made two trips, one made three, 15 made four, and three went five times. Twenty-one members of the group contributed their talents on Spacelab or other research missions and three performed work with the great observatories Hubble and Chandra. Thirteen participated in the Shuttle Mir program, with 11 visiting the orbiting facility, one of them twice, another three times, and one completing a long-duration mission. Fifteen visited the International Space Station, five twice, participating in its assembly, research, maintenance, and logistics, with five completing long-duration missions aboard the facility. Eleven of the 23 performed 37 spacewalks spending 242 hours, or more than 10 days, outside their spacecraft.  

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    • By NASA
      Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More 35th Anniversary 2 min read
      Hubble Captures Young Stars Changing Their Environments
      This NASA/ESA Hubble Space Telescope image features the nearest star-forming region to Earth, the Orion Nebula (Messier 42, M42), located some 1,500 light-years away. ESA/Hubble, NASA, and T. Megeath This NASA/ESA Hubble Space Telescope image peers into the dusty recesses of the nearest massive star-forming region to Earth, the Orion Nebula (Messier 42, M42). Just 1,500 light-years away, the Orion Nebula is visible to the unaided eye below the three stars that form the ‘belt’ in the constellation Orion. The nebula is home to hundreds of newborn stars including the subject of this image: the protostars HOPS 150 and HOPS 153.
      These protostars get their names from the Herschel Orion Protostar Survey, conducted with ESA’s Herschel Space Observatory. The object visible in the upper-right corner of this image is HOPS 150: it’s a binary star system where two young protostars orbit each other. Each star has a small, dusty disk of material surrounding it. These stars gather material from their respective dust disks, growing in the process. The dark line that cuts across the bright glow of these protostars is a cloud of gas and dust falling in on the pair of protostars. It is over 2,000 times wider than the distance between Earth and the Sun. Based on the amount of infrared light HOPS 150 is emitting, as compared to other wavelengths it emits, the protostars are mid-way down the path to becoming mature stars.
      Extending across the left side of the image is a narrow, colorful outflow called a jet. This jet comes from the nearby protostar HOPS 153, which is out of the frame. HOPS 153 is significantly younger than its neighbor. That stellar object is still deeply embedded in its birth nebula and enshrouded by a cloud of cold, dense gas. While Hubble cannot penetrate this gas to see the protostar, the jet HOPS 153 emitted is brightly and clearly visible as it plows into the surrounding gas and dust of the Orion Nebula.
      The transition from tightly swaddled protostar to fully fledged star will dramatically affect HOPS 153’s surroundings. As gas falls onto the protostar, its jets spew material and energy into interstellar space, carving out bubbles and heating the gas. By stirring up and warming nearby gas, HOPS 153 may regulate the formation of new stars in its neighborhood and even slow its own growth.
      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Explore More

      Three-Year Study of Young Stars with NASA’s Hubble Enters New Chapter


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      Bow Shock Near a Young Star

      Media Contact:
      Claire Andreoli (claire.andreoli@nasa.gov)
      NASA’s Goddard Space Flight Center, Greenbelt, MD
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      Details
      Last Updated Jan 16, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
      Astrophysics Astrophysics Division Goddard Space Flight Center Hubble Space Telescope Nebulae Protostars Stars The Universe Keep Exploring Discover More Topics From Hubble
      Hubble Space Telescope


      Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


      Exploring the Birth of Stars



      Hubble’s Night Sky Challenge



      Hubble Focus: The Lives of Stars


      This e-book highlights the mission’s recent discoveries and observations related to the birth, evolution, and death of stars.

      View the full article
    • By NASA
      Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More 35th Anniversary 6 Min Read NASA’s Hubble Traces Hidden History of Andromeda Galaxy
      This photomosaic of the Andromeda galaxy is the largest ever assembled from Hubble observations. Credits:
      NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI) In the years following the launch of NASA’s Hubble Space Telescope, astronomers have tallied over 1 trillion galaxies in the universe. But only one galaxy stands out as the most important nearby stellar island to our Milky Way — the magnificent Andromeda galaxy (Messier 31). It can be seen with the naked eye on a very clear autumn night as a faint cigar-shaped object roughly the apparent angular diameter of our Moon.
      A century ago, Edwin Hubble first established that this so-called “spiral nebula” was actually very far outside our own Milky Way galaxy — at a distance of approximately 2.5 million light-years or roughly 25 Milky Way diameters. Prior to that, astronomers had long thought that the Milky way encompassed the entire universe. Overnight, Hubble’s discovery turned cosmology upside down by unveiling an infinitely grander universe.
      Now, a century later, the space telescope named for Hubble has accomplished the most comprehensive survey of this enticing empire of stars. The Hubble telescope is yielding new clues to the evolutionary history of Andromeda, and it looks markedly different from the Milky Way’s history.
      This is largest photomosaic ever assembled from Hubble Space Telescope observations. It is a panoramic view of the neighboring Andromeda galaxy, located 2.5 million light-years away. It took over 10 years to make this vast and colorful portrait of the galaxy, requiring over 600 Hubble overlapping snapshots that were challenging to stitch together. The galaxy is so close to us, that in angular size it is six times the apparent diameter of the full Moon, and can be seen with the unaided eye. For Hubble’s pinpoint view, that’s a lot of celestial real estate to cover. This stunning, colorful mosaic captures the glow of 200 million stars. That’s still a fraction of Andromeda’s population. And the stars are spread across about 2.5 billion pixels. The detailed look at the resolved stars will help astronomers piece together the galaxy’s past history that includes mergers with smaller satellite galaxies. NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI)
      Download this image (10,552 x 2,468)(9 MB)


      Download this image (42,208 x 9,870)(203 MB)

      Without Andromeda as a proxy for spiral galaxies in the universe at large, astronomers would know much less about the structure and evolution of our own Milky Way. That’s because we are embedded inside the Milky Way. This is like trying to understand the layout of New York City by standing in the middle of Central Park.
      “With Hubble we can get into enormous detail about what’s happening on a holistic scale across the entire disk of the galaxy. You can’t do that with any other large galaxy,” said principal investigator Ben Williams of the University of Washington. Hubble’s sharp imaging capabilities can resolve more than 200 million stars in the Andromeda galaxy, detecting only stars brighter than our Sun. They look like grains of sand across the beach. But that’s just the tip of the iceberg. Andromeda’s total population is estimated to be 1 trillion stars, with many less massive stars falling below Hubble’s sensitivity limit.
      Photographing Andromeda was a herculean task because the galaxy is a much bigger target on the sky than the galaxies Hubble routinely observes, which are often billions of light-years away. The full mosaic was carried out under two Hubble programs. In total, it required over 1,000 Hubble orbits, spanning more than a decade.
      This panorama started with the Panchromatic Hubble Andromeda Treasury (PHAT) program about a decade ago. Images were obtained at near-ultraviolet, visible, and near-infrared wavelengths using the Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble to photograph the northern half of Andromeda.
      This is the largest photomosaic ever made by the Hubble Space Telescope. The target is the vast Andromeda galaxy that is only 2.5 million light-years from Earth, making it the nearest galaxy to our own Milky Way. Andromeda is seen almost edge-on, tilted by 77 degrees relative to Earth’s view. The galaxy is so large that the mosaic is assembled from approximately 600 separate overlapping fields of view taken over 10 years of Hubble observing — a challenge to stitch together over such a large area. The mosaic image is made up of at least 2.5 billion pixels. Hubble resolves an estimated 200 million stars that are hotter than our Sun, but still a fraction of the galaxy’s total estimated stellar population. Interesting regions include: (a) Clusters of bright blue stars embedded within the galaxy, background galaxies seen much farther away, and photo-bombing by a couple bright foreground stars that are actually inside our Milky Way; (b) NGC 206 the most conspicuous star cloud in Andromeda; (c) A young cluster of blue newborn stars; (d) The satellite galaxy M32, that may be the residual core of a galaxy that once collided with Andromeda; (e) Dark dust lanes across myriad stars.
      NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI)
      Download this image (2,000 x 1,125)(1.5 MB)


      Download this image (7,680 x 4,320)(16 MB)

      This program was followed up by the Panchromatic Hubble Andromeda Southern Treasury (PHAST), recently published in The Astrophysical Journal and led by Zhuo Chen at the University of Washington, which added images of approximately 100 million stars in the southern half of Andromeda. This region is structurally unique and more sensitive to the galaxy’s merger history than the northern disk mapped by the PHAT survey.
      The combined programs collectively cover the entire disk of Andromeda, which is seen almost edge-on — tilted by 77 degrees relative to Earth’s view. The galaxy is so large that the mosaic is assembled from approximately 600 separate fields of view. The mosaic image is made up of at least 2.5 billion pixels.
      The complementary Hubble survey programs provide information about the age, heavy-element abundance, and stellar masses inside Andromeda. This will allow astronomers to distinguish between competing scenarios where Andromeda merged with one or more galaxies. Hubble’s detailed measurements constrain models of Andromeda’s merger history and disk evolution.
      A Galactic ‘Train Wreck’
      Though the Milky Way and Andromeda formed presumably around the same time many billions of years ago, observational evidence shows that they have very different evolutionary histories, despite growing up in the same cosmological neighborhood. Andromeda seems to be more highly populated with younger stars and unusual features like coherent streams of stars, say researchers. This implies it has a more active recent star-formation and interaction history than the Milky Way.
      “Andromeda’s a train wreck. It looks like it has been through some kind of event that caused it to form a lot of stars and then just shut down,” said Daniel Weisz at the University of California, Berkeley. “This was probably due to a collision with another galaxy in the neighborhood.”
      A possible culprit is the compact satellite galaxy Messier 32, which resembles the stripped-down core of a once-spiral galaxy that may have interacted with Andromeda in the past. Computer simulations suggest that when a close encounter with another galaxy uses up all the available interstellar gas, star formation subsides.
      The Andromeda Galaxy, our closest galactic neighbor, holds over 1 trillion stars and has been a key to unlocking the secrets of the universe. Thanks to NASA’s Hubble Space Telescope, we’re now seeing Andromeda in stunning new detail, revealing its dynamic history and unique structure.
      Credit: NASA’s Goddard Space Flight Center; Lead Producer: Paul Morris
      Download this video

      “Andromeda looks like a transitional type of galaxy that’s between a star-forming spiral and a sort of elliptical galaxy dominated by aging red stars,” said Weisz. “We can tell it’s got this big central bulge of older stars and a star-forming disk that’s not as active as you might expect given the galaxy’s mass.”
      “This detailed look at the resolved stars will help us to piece together the galaxy’s past merger and interaction history,” added Williams.
      Hubble’s new findings will support future observations by NASA’s James Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope. Essentially a wide-angle version of Hubble (with the same sized mirror), Roman will capture the equivalent of at least 100 high-resolution Hubble images in a single exposure. These observations will complement and extend Hubble’s huge dataset.
      The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
      Explore More

      Explore the Night Sky: Messier 31


      Hubble’s High-Definition Panoramic View of the Andromeda Galaxy


      NASA’s Hubble Finds Giant Halo Around the Andromeda Galaxy

      Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
      Claire Andreoli (claire.andreoli@nasa.gov)
      NASA’s Goddard Space Flight Center, Greenbelt, MD
      Ray Villard
      Space Telescope Science Institute, Baltimore, MD
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      Details
      Last Updated Jan 16, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
      Andromeda Galaxy Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Hubble Space Telescope Spiral Galaxies The Universe Keep Exploring Discover More Topics From Hubble
      Hubble Space Telescope


      Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.


      Hubble Science



      Hubble’s Night Sky Challenge



      Hubble Images


      View the full article
    • By NASA
      3 min read
      NASA Solar Observatory Sees Coronal Loops Flicker Before Big Flares
      For decades, scientists have tried in vain to accurately predict solar flares — intense bursts of light on the Sun that can send a flurry of charged particles into the solar system. Now, using NASA’s Solar Dynamics Observatory, one team has identified flickering loops in the solar atmosphere, or corona, that seem to signal when the Sun is about to unleash a large flare.
      These warning signs could help NASA and other stakeholders protect astronauts as well as technology both in space and on the ground from hazardous space weather.
      NASA’s Solar Dynamics Observatory captured this image of coronal loops above an active region on the Sun in mid-January 2012. The image was taken in the 171 angstrom wavelength of extreme ultraviolet light. NASA/Solar Dynamics Observatory Led by heliophysicist Emily Mason of Predictive Sciences Inc. in San Diego, California, the team studied arch-like structures called coronal loops along the edge of the Sun. Coronal loops rise from magnetically driven active regions on the Sun, where solar flares also originate.
      The team looked at coronal loops near 50 strong solar flares, analyzing how their brightness in extreme ultraviolet light varied in the hours before a flare compared to loops above non-flaring regions. Like flashing warning lights, the loops above flaring regions varied much more than those above non-flaring regions.
      “We found that some of the extreme ultraviolet light above active regions flickers erratically for a few hours before a solar flare,” Mason explained. “The results are really important for understanding flares and may improve our ability to predict dangerous space weather.”
      Published in the Astrophysical Journal Letters in December 2024 and presented on Jan. 15, 2025, at a press conference during the 245th meeting of the American Astronomical Society, the results also hint that the flickering reaches a peak earlier for stronger flares. However, the team says more observations are needed to confirm this link.
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      supports HTML5 video
      The four panels in this movie show brightness changes in coronal loops in four different wavelengths of extreme ultraviolet light (131, 171, 193, and 304 angstroms) before a solar flare in December 2011. The images were taken by the Atmospheric Imaging Assembly (AIA) on NASA’s Solar Dynamics Observatory and processed to reveal flickering in the coronal loops. NASA/Solar Dynamics Observatory/JHelioviewer/E. Mason Other researchers have tried to predict solar flares by examining magnetic fields on the Sun, or by looking for consistent trends in other coronal loop features. However, Mason and her colleagues believe that measuring the brightness variations in coronal loops could provide more precise warnings than those methods — signaling oncoming flares 2 to 6 hours ahead of time with 60 to 80 percent accuracy.
      “A lot of the predictive schemes that have been developed are still predicting the likelihood of flares in a given time period and not necessarily exact timing,” said team member Seth Garland of the Air Force Institute of Technology at Wright-Patterson Air Force Base in Ohio.
      Each solar flare is like a snowflake — every single flare is unique.
      Kara kniezewski
      Air Force Institute of Technology
      “The Sun’s corona is a dynamic environment, and each solar flare is like a snowflake — every single flare is unique,” said team member Kara Kniezewski, a graduate student at the Air Force Institute of Technology and lead author of the paper. “We find that searching for periods of ‘chaotic’ behavior in the coronal loop emission, rather than specific trends, provide a much more consistent metric and may also correlate with how strong a flare will be.”
      The scientists hope their findings about coronal loops can eventually be used to help keep astronauts, spacecraft, electrical grids, and other assets safe from the harmful radiation that accompanies solar flares. For example, an automated system could look for brightness changes in coronal loops in real-time images from the Solar Dynamics Observatory and issue alerts.
      “Previous work by other researchers reports some interesting prediction metrics,” said co-author Vadim Uritsky of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the Catholic University of Washington in D.C. “We could build on this and come up with a well-tested and, ideally, simpler indicator ready for the leap from research to operations.”
      By Vanessa Thomas
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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      Details
      Last Updated Jan 15, 2025 Related Terms
      Goddard Space Flight Center Heliophysics Heliophysics Division Space Weather The Sun Explore More
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