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GPM Celebrates Ten Years of Observing Precipitation for Science and Society
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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
Insights into metal alloy solidification
Researchers report details of phase and structure in the solidification of metal alloys on the International Space Station, including formation of microstructures. Because these microstructures determine a material’s mechanical properties, this work could support improvements in techniques for producing coatings and additive manufacturing or 3D printing processes.
METCOMP, an ESA (European Space Agency) investigation, studied solidification in microgravity using transparent organic mixtures as stand-ins for metal alloys. Conducting the research in microgravity removed the influence of convection and other effects of gravity. Results help scientists better understand and validate models of solidification mechanisms, enabling better forecasting of microstructures and improving manufacturing processes.
Image from the METCOMP investigation of how a metal alloy could look like as it solidifies. E-USOC Measuring the height of upper-atmospheric electrical discharges
Researchers determined the height of a blue discharge from a thundercloud using ground-based electric field measurements and space-based optical measurements from Atmosphere-Space Interactions Monitor (ASIM). This finding helps scientists better understand how these high-altitude lightning-related events affect atmospheric chemistry and could help improve atmospheric models and climate and weather predictions.
ESA’s ASIM is an Earth observation facility that studies severe thunderstorms and upper-atmospheric lighting events and their role in the Earth’s atmosphere and climate. Upper-atmospheric lightning, also known as transient luminous events, occurs well above the altitudes of normal lightning and storm clouds. The data collected by ASIM could support research on the statistical properties of many upper atmosphere lightning events, such as comparison of peak intensities of blue and red pulses with reports from lightning detection networks.
An artist’s impression of a blue jet as observed from the International Space Station.Mount Visual/University of Bergen/DTU Modeling a complex neutron star
Scientists report that they can use modeling of neutron star PSRJ1231−1411’s X-ray pulses to infer its mass and radius and narrow the possible behaviors of the dense matter at its core. This finding provides a better understanding of the composition and structure of these celestial objects, improving models that help answer questions about conditions in the universe.
The Neutron star Interior Composition Explorer provides high-precision measurements of pulses of X-ray radiation from neutron stars. This particular neutron star presented challenges in finding a fit between models and data, possibly due to fundamental issues with its pulse profile. The authors recommend a program of simulations using synthetic data to determine whether there are fundamental issues with this type of pulse profile that could prevent efforts to obtain tighter and more robust constraints.
Concentrators on the Neutron star Interior Composition Explorer instrument.NASAView the full article
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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
With the historic first international space docking mission only six months away, preparations on the ground for the Apollo-Soyuz Test Project (ASTP) intensified. At NASA’s Kennedy Space Center (KSC) in Florida, workers in the Vehicle Assembly Building (VAB) stacked the rocket for the mission, the final Saturn rocket assembled for flight. In the nearby Manned Spacecraft Operations Building (MSOB), the Apollo prime crew of Commander Thomas Stafford, Command Module Pilot Vance Brand, and Docking Module Pilot Donald “Deke” Slayton, and their backups Alan Bean, Ronald Evans, and Jack Lousma conducted vacuum chamber tests of the Command Module (CM), the final Apollo spacecraft prepared for flight.
Inside the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida, workers attach fins to the Saturn IB’s first stage. In the VAB, workers secure the first stage of the Saturn IB rocket onto the milk stool, perched on Mobile Launcher-1. Workers lift the second stage of the Saturn IB rocket prior to mating with the first stage. Workers lower a boilerplate Apollo spacecraft onto the Saturn IB rocket. The Saturn IB rocket, serial number SA-210, used for ASTP had a lengthy history. Contractors originally built its two stages in 1967, at a time when NASA planned many more Saturn IB flights to test Apollo spacecraft components in Earth orbit in preparation for the Moon landing. By 1968, however, after four uncrewed Saturn IB launches, only one launched a crew, Apollo 7. Four more Saturn IBs remained on reserve to launch crews as part of the Apollo Applications Program, renamed Skylab in 1970. Without an immediate mission, the two stages of SA-210 entered long-term storage in 1967. Workers later modified and refurbished the stages for ASTP before shipping them to KSC. The first stage arrived in April 1974 and the second stage in November 1972.
On Jan. 13, 1975, inside the cavernous VAB, workers stacked the Saturn IB rocket’s first stage onto Mobile Launcher-1 (ML-1), modified from its use to launch Saturn V rockets during the Apollo program with the addition of the milk stool pedestal. The milk stool, a 128-foot tall platform, allowed the Saturn IB to use the same Launch Umbilical Tower as the much larger Saturn V rocket at Launch Complex 39. The next day, workers lowered the second stage onto the first, followed by the Instrument Unit two days later. Finally, on Jan. 17 workers topped off the rocket with a boilerplate Apollo spacecraft while engineers continued testing the flight article in the MSOB.
The ASTP Apollo Command and Service Modules arrive at NASA’s Kennedy Space Center (KSC) in Florida. The ASTP Command Module arrives in KSC’s Manned Spacecraft Operations Building. The Command and Service Modules – CSM-111 – arrived at KSC from the Rockwell International plant in Downey, California, on Sept. 8, 1974, by C-5A Galaxy cargo plane. Rockwell had finished building the spacecraft in March 1970 and placed it in storage until July 1972. Modifications for ASTP took place between August 1972 and August 1974, following which Rockwell shipped the spacecraft to KSC. The sign on the shipping container bore the legend “From A to Soyuz – Apollo/Soyuz – Last and the Best.” Workers at KSC towed the modules to the MSOB for inspection and checkout, joined the two modules, and placed the combined spacecraft into a vacuum chamber.
The prime Apollo crew of Thomas Stafford, left, Vance Brand, and Donald “Deke” Slayton suit up in preparation for an altitude chamber test in the Command Module (CM). The astronauts inside the CM in the altitude chamber. In the MSOB, the prime and backup ASTP crews conducted tests of their spacecraft in an altitude chamber. After both crews completed simulated runs in December 1974, the prime crew of Stafford, Brand, and Slayton suited up, entered the CM inside the chamber, closed the hatch, and conducted an actual test on Jan. 14, with the chamber simulating altitudes of up to 220,000 feet. Two days later, the backup crew of Bean, Evans, and Lousma completed a similar test.
he backup Apollo crew of Alan Bean, left, Ronald Evans, and Jack Lousma suit up in preparation for an altitude chamber test in the Command Module (CM). Workers assist backup crewmember Lousma into the CM. To solve the problem of the Apollo and Soyuz spacecraft operating at different atmospheric pressures and compositions and using incompatible docking mechanisms, engineers designed a Docking Module (DM) that acted as both an airlock and a transfer tunnel and a Docking System (DS) that allowed the two nations’ spacecraft to physically join in space. NASA contracted with Rockwell International to build the DM. Engineers equipped one end of the DM with the standard Apollo probe-and-drogue docking mechanism and the other end with the androgynous system that linked up with its opposite half installed on the modified Soyuz spacecraft. During launch, the DM rested inside the Spacecraft Lunar Module (LM) Adaptor (SLA) atop the rocket’s upper stage, much like the LM during Apollo flights. Once in orbit, the astronauts separated the CSM from the upper stage, turned the spacecraft around, docked with the DM and pulled it free.
Workers lower the DM into Chamber B in the Space Environment Simulation Laboratory at NASA’s Johnson Space Center in Houston. Workers lower the DM into Chamber B in the Space Environment Simulation Laboratory at NASA’s Johnson Space Center in Houston. After extensive vacuum testing in Chamber B of the Space Environment Simulation Laboratory at NASA’s Johnson Space Center in Houston, the flight DM arrived at KSC on Oct. 29, 1974, and workers prepared it for more testing in a vacuum chamber in the MSOB. The flight DS arrived at KSC on Jan. 3, 1975, and two weeks later workers installed it on the DM. On Jan. 27, engineers lowered the DM onto the CM in the altitude chamber to conduct a mechanical docking test. Engineers conducted 10 days of joint tests of television and audio equipment to ensure systems compatibility.
Workers conduct a docking test of the Docking Module with the Command Module at NASA’s Kennedy Space Center in Florida. NASA support astronaut Robert Overmyer, right, works with engineers during compatibility testing. To be continued…
Major events around the world in January 1975:
January 5 – Musical The Wiz opens on Broadway, runs for 1,672 performances.
January 6 – The game show Wheel of Fortune debuts on NBC.
January 8 – Ella Grasso of Connecticut becomes the first elected female governor in the U.S.
January 11 – The S-II second stage of the Saturn V rocket that launched Skylab reenters the Earth’s atmosphere over the Indian Ocean.
January 12 – The Pittsburg Steelers beat the Minnesota Vikings in Super Bowl IX, played in Tulane Stadium in New Orleans.
January 15 – Space Mountain opens at Disney World in Orlando.
January 18 – The Jeffersons premieres on CBS.
January 22 – Launch of the Landsat-2 Earth resources monitoring satellite.
January 30 – Ernő Rubik applies for a patent in Hungary for his Magic Cube, later known as Rubik’s Cube.
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By NASA
Hubble Space TelescopeHubble Home OverviewAbout Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & BenefitsHubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts ScienceHubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky ObservatoryHubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb TeamHubble Team Career Aspirations Hubble Astronauts NewsHubble News Hubble News Archive Social Media Media Resources MultimediaMultimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More35th Anniversary 7 Min Read NASA Celebrates Edwin Hubble’s Discovery of a New Universe
The Cepheid variable star, called V1, in the neighboring Andromeda galaxy. Credits: NASA, ESA, Hubble Heritage Team (STScI/AURA); Acknowledgement: R. Gendler For humans, the most important star in the universe is our Sun. The second-most important star is nestled inside the Andromeda galaxy. Don’t go looking for it — the flickering star is 2.2 million light-years away, and is 1/100,000th the brightness of the faintest star visible to the human eye.
Yet, a century ago, its discovery by Edwin Hubble, then an astronomer at Carnegie Observatories, opened humanity’s eyes as to how large the universe really is, and revealed that our Milky Way galaxy is just one of hundreds of billions of galaxies in the universe ushered in the coming-of-age for humans as a curious species that could scientifically ponder our own creation through the message of starlight. Carnegie Science and NASA are celebrating this centennial at the 245th meeting of the American Astronomical Society in Washington, D.C.
The seemingly inauspicious star, simply named V1, flung open a Pandora’s box full of mysteries about time and space that are still challenging astronomers today. Using the largest telescope in the world at that time, the Carnegie-funded 100-inch Hooker Telescope at Mount Wilson Observatory in California, Hubble discovered the demure star in 1923. This rare type of pulsating star, called a Cepheid variable, is used as milepost markers for distant celestial objects. There are no tape-measures in space, but by the early 20th century Henrietta Swan Leavitt had discovered that the pulsation period of Cepheid variables is directly tied to their luminosity.
Many astronomers long believed that the edge of the Milky Way marked the edge of the entire universe. But Hubble determined that V1, located inside the Andromeda “nebula,” was at a distance that far exceeded anything in our own Milky Way galaxy. This led Hubble to the jaw-dropping realization that the universe extends far beyond our own galaxy.
In fact Hubble had suspected there was a larger universe out there, but here was the proof in the pudding. He was so amazed he scribbled an exclamation mark on the photographic plate of Andromeda that pinpointed the variable star.
In commemoration of Edwin Hubble’s discovery of a Cepheid variable class star, called V1, in the neighboring Andromeda galaxy 100 years ago, astronomers partnered with the American Association of Variable Star Observers (AAVSO) to study the star. AAVSO observers followed V1 for six months, producing a plot, or light curve, of the rhythmic rise and fall of the star’s light. Based on this data, the Hubble Space Telescope was scheduled to capture the star at its dimmest and brightest light. Edwin Hubble’s observations of V1 became the critical first step in uncovering a larger, grander universe than some astronomers imagined at the time. Once dismissed as a nearby “spiral nebula” measurements of Andromeda with its embedded Cepheid star served as a stellar milepost marker. It definitively showed that Andromeda was far outside of our Milky Way. Edwin Hubble went on to measure the distances to many galaxies beyond the Milky Way by finding Cepheid variables within those levels. The velocities of those galaxies, in turn, allowed him to determine that the universe is expanding.NASA, ESA, Hubble Heritage Team (STScI/AURA); Acknowledgment: R. Gendler As a result, the science of cosmology exploded almost overnight. Hubble’s contemporary, the distinguished Harvard astronomer Harlow Shapley, upon Hubble notifying him of the discovery, was devastated. “Here is the letter that destroyed my universe,” he lamented to fellow astronomer Cecilia Payne-Gaposchkin, who was in his office when he opened Hubble’s message.
Just three years earlier, Shapley had presented his observational interpretation of a much smaller universe in a debate one evening at the Smithsonian Museum of Natural History in Washington. He maintained that the Milky Way galaxy was so huge, it must encompass the entirety of the universe. Shapley insisted that the mysteriously fuzzy “spiral nebulae,” such as Andromeda, were simply stars forming on the periphery of our Milky Way, and inconsequential.
Little could Hubble have imagined that 70 years later, an extraordinary telescope named after him, lofted hundreds of miles above the Earth, would continue his legacy. The marvelous telescope made “Hubble” a household word, synonymous with wonderous astronomy.
Today, NASA’s Hubble Space Telescope pushes the frontiers of knowledge over 10 times farther than Edwin Hubble could ever see. The space telescope has lifted the curtain on a compulsive universe full of active stars, colliding galaxies, and runaway black holes, among the celestial fireworks of the interplay between matter and energy.
Edwin Hubble was the first astronomer to take the initial steps that would ultimately lead to the Hubble Space Telescope, revealing a seemingly infinite ocean of galaxies. He thought that, despite their abundance, galaxies came in just a few specific shapes: pinwheel spirals, football-shaped ellipticals, and oddball irregular galaxies. He thought these might be clues to galaxy evolution – but the answer had to wait for the Hubble Space Telescope’s legendary Hubble Deep Field in 1994.
The most impactful finding that Edwin Hubble’s analysis showed was that the farther the galaxy is, the faster it appears to be receding from Earth. The universe looked like it was expanding like a balloon. This was based on Hubble tying galaxy distances to the reddening of light — the redshift – that proportionally increased the father away the galaxies are.
The redshift data were first collected by Lowell Observatory astronomer Vesto Slipher, who spectroscopically studied the “spiral nebulae” a decade before Hubble. Slipher did not know they were extragalactic, but Hubble made the connection. Slipher first interpreted his redshift data an example of the Doppler effect. This phenomenon is caused by light being stretched to longer, redder wavelengths if a source is moving away from us. To Slipher, it was curious that all the spiral nebulae appeared to be moving away from Earth.
Two years prior to Hubble publishing his findings, the Belgian physicist and Jesuit priest Georges Lemaître analyzed the Hubble and Slifer observations and first came to the conclusion of an expanding universe. This proportionality between galaxies’ distances and redshifts is today termed Hubble–Lemaître’s law.
Because the universe appeared to be uniformly expanding, Lemaître further realized that the expansion rate could be run back into time – like rewinding a movie – until the universe was unimaginably small, hot, and dense. It wasn’t until 1949 that the term “big bang” came into fashion.
This was a relief to Edwin Hubble’s contemporary, Albert Einstein, who deduced the universe could not remain stationary without imploding under gravity’s pull. The rate of cosmic expansion is now known as the Hubble Constant.
Ironically, Hubble himself never fully accepted the runaway universe as an interpretation of the redshift data. He suspected that some unknown physics phenomenon was giving the illusion that the galaxies were flying away from each other. He was partly right in that Einstein’s theory of special relativity explained redshift as an effect of time-dilation that is proportional to the stretching of expanding space. The galaxies only appear to be zooming through the universe. Space is expanding instead.
Compass and scale image titled “Cepheid Variable Star V1 in M31 HST WFC3/UVIS.” Four boxes each showing a bright white star in the center surrounded by other stars. Each box has a correlating date at the bottom: Dec. 17, 2020, Dec. 21, 2010, Dec. 30, 2019, and Jan. 26, 2011. The center star in the boxes appears brighter with each passing date.NASA, ESA, Hubble Heritage Project (STScI, AURA) After decades of precise measurements, the Hubble telescope came along to nail down the expansion rate precisely, giving the universe an age of 13.8 billion years. This required establishing the first rung of what astronomers call the “cosmic distance ladder” needed to build a yardstick to far-flung galaxies. They are cousins to V1, Cepheid variable stars that the Hubble telescope can detect out to over 100 times farther from Earth than the star Edwin Hubble first found.
Astrophysics was turned on its head again in 1998 when the Hubble telescope and other observatories discovered that the universe was expanding at an ever-faster rate, through a phenomenon dubbed “dark energy.” Einstein first toyed with this idea of a repulsive form of gravity in space, calling it the cosmological constant.
Even more mysteriously, the current expansion rate appears to be different than what modern cosmological models of the developing universe would predict, further confounding theoreticians. Today astronomers are wrestling with the idea that whatever is accelerating the universe may be changing over time. NASA’s Roman Space Telescope, with the ability to do large cosmic surveys, should lead to new insights into the behavior of dark matter and dark energy. Roman will likely measure the Hubble constant via lensed supernovae.
This grand century-long adventure, plumbing depths of the unknown, began with Hubble photographing a large smudge of light, the Andromeda galaxy, at the Mount Wilson Observatory high above Los Angeles.
In short, Edwin Hubble is the man who wiped away the ancient universe and discovered a new universe that would shrink humanity’s self-perception into being an insignificant speck in the cosmos.
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.
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Edwin Hubble Hubble Views the Star That Changed the Universe The History of Hubble 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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Last Updated Jan 15, 2025 EditorAndrea GianopoulosLocationNASA Goddard Space Flight Center Related Terms
Andromeda Galaxy Astrophysics Astrophysics Division Goddard Space Flight Center Hubble Space Telescope 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.
Discovering a Runaway Universe
Our cosmos is growing, and that expansion rate is accelerating.
The History of Hubble
Hubble’s Night Sky Challenge
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