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A Really Neat Close-up of Comet NEAT from Kitt Peak Observatory
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By NASA
On July 23, 1999, space shuttle Columbia took to the skies on its 26th trip into space, to deliver its heaviest payload ever – the Chandra X-ray Observatory. The STS-93 crew included Commander Eileen M. Collins, the first woman to command a space shuttle mission, Pilot Jeffrey S. Ashby, and Mission Specialists Catherine “Cady” G. Coleman, Steven A. Hawley, and Michel A. Tognini of the French Space Agency (CNES). On the mission’s first day, they deployed Chandra, the most powerful X-ray telescope. With a planned five-year lifetime, Chandra continues its observations after a quarter century. For the next four days, the astronauts worked on twenty secondary middeck payloads and conducted Earth observations. The successful five-day mission ended with a night landing.
Left: The STS-93 crew patch. Middle: Official photo of the STS-93 crew of Eileen M. Collins, left, Steven A. Hawley, Jeffrey S. Ashby, Michel A. Tognini of France, and Catherine “Cady” G. Coleman. Right: The patch for the Chandra X-ray Observatory.
Tognini, selected by CNES in 1985 and a member of NASA’s class of 1995, received the first assignment to STS-93 in November 1997. He previously flew aboard Mir as a cosmonaut researcher, spending 14 days aboard the station in 1992. On March 5, 1998, First Lady Hilary R. Clinton announced Collins’ assignment as the first woman space shuttle commander in a ceremony at the White House together with President William J. “Bill” Clinton. NASA announced the rest of the crew the same day. For Collins, selected in the class of 1990, STS-93 represented her third space mission, having previously served as pilot on STS-63 and STS-84. Ashby, a member of the class of 1994, made his first flight aboard STS-93, while Coleman, selected in 1992, made her second flight, having flown before on STS-73. Hawley made his fifth flight, having previously served as a mission specialist on STS-41D, STS-61C, STS-31, and STS-82. He has the distinction of making the last flight by any member of his class of 1978, more than 21 years after his selection.
Left: Schematic of the Chandra X-ray Observatory showing its major components. Right: Diagram of the trajectory Chandra took to achieve its final operational 64-hour orbit around the Earth – IUS refers to the two burns of the Inertial Upper Stage and IPS to the five burns of Chandra’s Integral Propulsion System.
Because the Earth’s atmosphere absorbs X-ray radiation emitted by cosmic sources, scientists first came up with the idea of a space-based X-ray telescope in the 1970s. NASA launched its first X-ray telescope called Einstein in 1978, but scientists needed a more powerful instrument, and they proposed the Advanced X-ray Astrophysics Facility (AXAF). After a major redesign of the telescope in 1992, in 1998 NASA renamed AXAF the Chandra X-ray Observatory after Indian American Nobel Prize-winning theoretical physicist Subrahmanyan Chandrasekhar who made significant contributions to our knowledge about stars, stellar evolution, and black holes. Chandra, the third of NASA’s four Great Observatories, can detect X-ray sources 100 times fainter than any previous X-ray telescope. At 50,162 pounds including the Inertial Upper Stage (IUS) it used to achieve its operational orbit, Chandra remains the heaviest payload ever launched by the space shuttle, and at 57 feet long, it took up nearly the entire length of the payload bay. It has far exceeded its expected five-year lifetime, still returning valuable science after 25 years.
Left: The STS-93 crew during the Terminal Countdown Demonstration Test. Middle: The Chandra X-ray Observatory loaded into Columbia’s payload bay. Right: Liftoff of Columbia on the STS-93 mission carrying the Chandra X-ray Observatory and the first woman shuttle commander.
Columbia returned to KSC following its previous flight, the STS-90 Neurolab mission, in May 1998. Workers in KSC’s Orbiter Processing Facility (OPF) serviced the orbiter and removed the previous payload. With all four orbiters at KSC at the same time, workers temporarily stowed Columbia in the Vehicle Assembly Building (VAB), returning it to the OPF for final preflight processing on April 15, 1999. Rollover of Columbia from the OPF to the VAB took place on June 2, where workers mated it with an external tank and two solid rocket boosters. Following integrated testing, the stack rolled out to Launch Pad 39B on June 7. The crew participated in the Terminal Countdown Demonstration Test on June 24. Workers placed Chandra in Columbia’s payload bay three days later.
On July 23, 1994, Columbia thundered into the night sky from KSC’s Launch Pad 39B to begin the STS-93 mission. Two previous launch attempts on July 20 and 22 resulted in scrubs due to a faulty sensor and bad weather, respectively. As Columbia rose into the sky, for the first time in shuttle history a woman sat in the commander’s seat. Far below, problems arose that could have led to a catastrophic abort scenario. During the engine ignition sequence, a gold pin in Columbia’s right engine came loose, ejected with great force by the rapid flow of hot gases, and struck the engine’s nozzle, punching holes in three of its hydrogen cooling tubes. Although small, the hydrogen leak caused the engine’s controller to increase the flow of oxidizer, making the engine run hotter than normal. Meanwhile, a short-circuit knocked out the center engine’s digital control unit (DCU) and the right engine’s backup DCU. Both engines continued powered flight without a redundant DCU, with a failure in either causing a catastrophic abort. Although this did not occur, the higher than expected oxidizer usage led to main engine cutoff occurring 1.5 seconds early, leaving Columbia in a lower than planned orbit. The shuttle’s Orbiter Maneuvering System engines made up for the deficit. The harrowing events of the powered flight prompted Ascent Flight Director John P. Shannon to comment, “Yikes! We don’t need any more of these.”
Left: Eileen M. Collins, the first woman shuttle commander, shortly after reaching orbit. Right: First time space flyer STS-93 Pilot Jeffrey S. Ashby, shortly after reaching space.
After reaching orbit, the crew opened the payload bay doors and deployed the shuttle’s radiators, and removed their bulky launch and entry suits, stowing them for the remainder of the flight. The astronauts prepared for the mission’s primary objective, deployment of Chandra, and also began activating some of the middeck experiments.
Left: The Chandra X-ray Observatory in Columbia’s payload bay shortly after reaching orbit. Middle: Chandra raised to the deployment angle. Right: Chandra departs Columbia.
Coleman had prime responsibility for deploying Chandra. After initial checkout of the telescope by ground teams, the astronauts tilted Chandra and the IUS to an angle of 29 degrees. After additional checks, they tilted it up to the release angle of 58 degrees. A little over seven hours after launch, Coleman deployed the Chandra/IUS stack. Collins and Ashby flew Columbia to a safe distance, and about an hour after deployment, the IUS fired its first stage engine for about two minutes, followed by a two-minute burn of the second stage. This placed Chandra in a temporary elliptical Earth orbit with a high point of 37,200 miles. After separation of the IUS, Chandra used its own propulsion system over the next 10 days to raise its altitude to 6,214 miles by 86,992 miles, its operational orbit, circling the Earth every 64 hours. For the next four days of the mission, the astronauts operated about 20 middeck experiments, including a technology demonstration of a treadmill vibration isolation system planned for the International Space Station.
Left: Michel A. Tognini works with the Commercial Generic Bioprocessing Apparatus. Middle: Jeffrey S. Ashby checks the status of the Space Tissue Lab experiment. Right: Catherine G. Coleman harvests plants from the Plant Growth in Microgravity experiment.
Left: Catherine G. Coleman, left, and Michel A. Tognini pose near the Lightweight Flexible Solar Array Hinge technology demonstration experiment. Middle: Stephen A. Hawley checks the status of the Micro Electromechanical Systems experiment. Right: Tognini places samples of the Biological Research in Canisters experiment into a gaseous nitrogen freezer.
Left: Eileen M. Collins runs on the Treadmill Vibration Isolation System. Middle: Stephen A. Hawley, left, and Michel A. Tognini operate the Southwest Ultraviolet Imaging System instrument. Right: Inflight photograph of the STS-93 crew.
A selection of the STS-93 crew Earth observation photographs. Left: Laguna Verde in Chile. Middle left: Sunrise over the Mozambique Channel. Middle right: Darling River and lakes in Australia. Right: The Society Islands of Bora Bora, Tahaa, and Raiatea.
Left: Eileen M. Collins prepares to bring Columbia home. Middle: Columbia streaks through the skies over NASA’s Johnson Space Center in Houston during reentry. Right: Collins guides Columbia to a smooth touchdown on the Shuttle Landing Facility at NASA’s Kennedy Space Center in Florida.
Left: Three holes visible in the hydrogen cooling tubes of Columbia’s right main engine, seen after landing. Middle: The STS-93 crew pose in front of Columbia on the Shuttle Landing Facility at NASA’s Kennedy Space Center in Florida. Right: Eileen M. Collins addresses the crowd at Houston’s Ellington Field during the welcome home ceremony for the STS-93 crew, as Vice President Albert “Al” A. Gore and other dignitaries listen.
At the end of five days, the astronauts finished the last of the experiments and prepared for the return to Earth. On July 28, they closed Columbia’s payload bay doors, donned their launch and entry suits, and strapped themselves into their seats for entry and landing. Collins piloted Columbia to a smooth landing on KSC’s Shuttle Landing Facility, completing the 12th night landing of the shuttle program. The crew had flown 80 orbits around the Earth in 4 days, 22 hours, and 50 minutes. Columbia wouldn’t fly again until March 2002, the STS-109 Hubble Servicing Mission-3B. A postflight investigation into the cause of the short on ascent that led to two DCUs failing revealed a wire with frayed insulation, likely caused by workers inadvertently stepping on it, that rubbed against a burred screw head that had likely been there since Columbia’s manufacture. The incident resulted in significant changes to ground processes during shuttle inspections and repairs. With regard to the pin ejected during engine ignition that damaged the hydrogen cooling tubes, investigators found that those pins never passed any acceptance testing. Since STS-93 marked the last flight of that generation of main engines, newer engines incorporated a different configuration, requiring no design or other changes.
Enjoy the crew narrate a video about the STS-93 mission. Read Hawley’s recollections of the STS-93 mission in his oral history with the JSC History Office.
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By NASA
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ESA, NASA Solar Observatory Discovers Its 5,000th Comet
On March 25, 2024, a citizen scientist in the Czech Republic spotted a comet in an image from the Solar and Heliospheric Observatory (SOHO) spacecraft, which has now been confirmed to be the 5,000th comet discovered using SOHO data. SOHO has achieved this milestone over 28 years in space, even though it was never designed to be a comet hunter.
The 5,000th comet discovered with the Solar and Heliospheric Observatory (SOHO) spacecraft is noted by a small white box in the upper left portion of this image. A zoomed-in inset shows the comet as a faint dot between the white vertical lines. The image was taken on March 25, 2024, by SOHO’s Large Angle and Spectrometric Coronagraph (LASCO), which uses a disk to block the bright Sun and reveal faint features around it. NASA/ESA/SOHO The comet is a small body made of ice and rock that takes only a few years to orbit the Sun. It belongs to the “Marsden group” of comets. This group is thought to be related to comet 96P/Machholz (which SOHO observes when Machholz passes near the Sun every 5.3 years) and is named for the late scientist Brian Marsden who first recognized the group using SOHO observations. Only about 75 of the 5,000 comets discovered with SOHO belong to the Marsden group.
A joint mission of ESA (European Space Agency) and NASA, SOHO launched in December 1995 to study the Sun and the dynamics in its outer atmosphere, called the corona. A science instrument on SOHO, called the Large Angle and Spectrometric Coronagraph (LASCO), uses an artificial disk to block the blinding light of the Sun so scientists can study the corona and environment immediately around the Sun.
This also allows SOHO to do something many other spacecraft cannot – see comets flying close to the Sun, known as “sungrazing” comets or “sungrazers.” Many of these comets only brighten when they’re too close to the Sun for other observatories to see and would otherwise go undetected, lost in the bright glare of our star. While scientists expected SOHO to serendipitously find some comets during its mission, the spacecraft’s ability to spot them has made it the most prolific comet-finder in history – discovering more than half of the comets known today.
In fact, soon after SOHO launched, people around the world began spotting so many comets in its images that mission scientists needed a way to keep track of them all. In the early 2000s, they launched the NASA-funded Sungrazer Project that allows anyone to report comets they find in SOHO images.
This animation shows the Solar and Heliospheric Observatory’s 5,000th comet (circled) moving across the field relative to background stars. The images in this sequence were taken with the spacecraft’s Large Angle and Spectrometric Coronagraph (LASCO) instrument. NASA/ESA/SOHO SOHO’s 5,000th comet was found by Hanjie Tan, a Sungrazer Project participant who is originally from Guangzhou, China, and is currently pursuing a doctoral degree in astronomy in Prague, Czech Republic. Tan has been participating in the Sungrazer Project since he was 13 years old and is one of the project’s youngest comet discoverers.
“Since 2009, I’ve discovered over 200 comets,” Tan said. “I got into the Sungrazer Project because I love looking for comets. It’s really exciting to be the first to see comets get bright near the Sun after they’ve been traveling through space for thousands of years.”
Most of the 5,000 comets discovered using SOHO have been found with the help of an international cadre of volunteer comet hunters – many with no formal scientific training – participating in the Sungrazer Project.
“Prior to the launch of the SOHO mission and the Sungrazer Project, there were only a couple dozen sungrazing comets on record – that’s all we knew existed,” said Karl Battams, a space scientist at the U.S. Naval Research Lab in Washington, D.C., and the principal investigator for the Sungrazer Project. “The fact that we’ve finally reached this milestone – 5,000 comets – is just unbelievable to me.”
SOHO’s 5,000th comet was discovered with the help of volunteers participating in the NASA-funded Sungrazer Project.
Credit: NASA’s Goddard Space Flight Center The vast number of comets discovered using SOHO has allowed scientists to learn more about sungrazing comets and groups of comets that orbit the Sun. Comets discovered by the Sungrazer Project have also helped scientists learn more about the Sun, by watching the comets plunge through our star’s atmosphere like small solar probes.
“The statistics of 5,000 comets, and looking at their orbits and trajectories through space, is a super unique dataset – it’s really valuable science,” Battams said. “It’s a testament to the countless hours the project participants have put into this. We absolutely would never had reached this milestone if it wasn’t for what the project volunteers have done.”
The Sungrazer Project is one of many opportunities that anyone can get involved with to help make discoveries with NASA during the Heliophysics Big Year, which extends through the end of 2024. Learn more about SOHO, the Sungrazer Project, and other NASA science projects you can participate in:
NASA SOHO mission website ESA SOHO website The Sungrazer Project Why ESA and NASA’s SOHO Spacecraft Spots So Many Comets 4,000th Comet Discovered by ESA & NASA Solar Observatory NASA Citizen Science by Vanessa Thomas
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Mar 27, 2024 Related Terms
Citizen Science Comets Heliophysics Skywatching SOHO (Solar and Heliospheric Observatory) The Solar System The Sun Explore More
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By NASA
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NASA Collaborating on European-led Gravitational Wave Observatory in Space
The LISA (Laser Interferometer Space Antenna) mission, led by ESA (European Space Agency) with NASA contributions, will detect gravitational waves in space using three spacecraft, separated by more than a million miles, flying in a triangular formation. Lasers fired between the satellites, shown in this artist’s concept, will measure how gravitational waves alter their relative distances. AEI/MM/Exozet The first space-based observatory designed to detect gravitational waves has passed a major review and will proceed to the construction of flight hardware. On Jan. 25, ESA (European Space Agency), announced the formal adoption of LISA, the Laser Interferometer Space Antenna, to its mission lineup, with launch slated for the mid-2030s. ESA leads the mission, with NASA serving as a collaborative partner.
“In 2015, the ground-based LIGO observatory cracked open the window into gravitational waves, disturbances that sweep across space-time, the fabric of our universe,” said Mark Clampin, director of the Astrophysics Division at NASA Headquarters in Washington. “LISA will give us a panoramic view, allowing us to observe a broad range of sources both within our galaxy and far, far beyond it. We’re proud to be part of this international effort to open new avenues to explore the secrets of the universe.”
The LISA mission will enable observations of gravitational waves produced by merging supermassive black holes, seen here in a computer simulation. Most big galaxies contain central black holes weighing millions of times the mass of our Sun. When these galaxies collide, eventually their black holes do too. Download high-resolution video from NASA’s Scientific Visualization Studio. Credit: NASA’s Goddard Space Flight Center/Scott Noble; simulation data, d’Ascoli et al. 2018 NASA will provide several key components of LISA’s instrument suite along with science and engineering support. NASA contributions include lasers, telescopes, and devices to reduce disturbances from electromagnetic charges. LISA will use this equipment as it measures precise distance changes, caused by gravitational waves, over millions of miles in space. ESA will provide the spacecraft and oversee the international team during the development and operation of the mission.
Gravitational waves were predicted by Albert Einstein’s general theory of relativity more than a century ago. They are produced by accelerating masses, such as a pair of orbiting black holes. Because these waves remove orbital energy, the distance between the objects gradually shrinks over millions of years, and they ultimately merge.
These ripples in the fabric of space went undetected until 2015, when LIGO, the Laser Interferometer Gravitational-Wave Observatory, funded by the U.S. National Science Foundation, measured gravitational waves from the merger of two black holes. This discovery furthered a new field of science called “multimessenger astronomy” in which gravitational waves could be used in conjunction with the other cosmic “messengers” – light and particles – to observe the universe in new ways.
Along with other ground-based facilities, LIGO has since observed dozens more black hole mergers, as well as mergers of neutron stars and neutron star-black hole systems. So far, the black holes detected through gravitational waves have been relatively small, with masses of tens to perhaps a hundred times that of our Sun. But scientists think that mergers of much more massive black holes were common when the universe was young, and only a space-based observatory could be sensitive to gravitational waves from them.
“LISA is designed to sense low-frequency gravitational waves that instruments on Earth cannot detect,” said Ira Thorpe, the NASA study scientist for the mission at the agency’s Goddard Space Flight Center in Greenbelt, Maryland. “These sources encompass tens of thousands of small binary systems in our own galaxy, as well as massive black holes merging as galaxies collided in the early universe.”
Gravitational waves from a simulated population of compact binary systems in our galaxy were used to construct this synthetic map of the entire sky. Such systems contain white dwarfs, neutron stars, or black holes in tight orbits. Maps like this using real data will be possible once the LISA mission becomes active in the next decade. The center of our Milky Way galaxy lies at the center of this all-sky view, with the galactic plane extending across the middle. Brighter spots indicate sources with stronger gravitational signals and lighter colors indicate those with higher frequencies. Larger colored patches show sources whose positions are less well known. NASA’s Goddard Space Flight Center LISA will consist of three spacecraft flying in a vast triangular formation that follows Earth in its orbit around the Sun. Each arm of the triangle stretches 1.6 million miles (2.5 million kilometers). The spacecraft will track internal test masses affected only by gravity. At the same time, they’ll continuously fire lasers to measure their separations to within a span smaller than the size of a helium atom. Gravitational waves from sources throughout the universe will produce oscillations in the lengths of the triangle’s arms, and LISA will capture these changes.
The underlying measurement technology was successfully demonstrated in space with ESA’s LISA Pathfinder mission, which operated between 2015 and 2017 and also included NASA participation. The spacecraft demonstrated the exquisite control and precise laser measurements needed for LISA.
By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media contacts:
Alise Fisher
Headquarters, Washington
(202) 358-2546
alise.m.fisher@nasa.gov
Claire Andreoli
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
(301) 286-1940
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Last Updated Jan 25, 2024 Related Terms
Astrophysics Black Holes Galaxies, Stars, & Black Holes Goddard Space Flight Center Gravitational Waves Jet Propulsion Laboratory Laser Interferometer Gravitational Wave Observatory (LIGO) LISA (Laser Interferometer Space Antenna) Stellar-mass Black Holes Supermassive Black Holes The Universe Uncategorized Explore More
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By Alex
Date: June 10, 2023
Las Vegas, known for its vibrant nightlife, bustling casinos, and extravagant entertainment, has recently witnessed an unprecedented event that has left both locals and tourists awe-struck. Reports have emerged of a remarkable sighting, sparking speculation and excitement across the city. Witnesses claim to have spotted extraterrestrial beings, commonly referred to as "aliens," roaming the iconic Las Vegas Strip.
Late in the evening on June 8, a cluster of eyewitnesses claimed to have observed peculiar activity near several prominent landmarks along the renowned boulevard. These witnesses reported the presence of otherworldly creatures, vividly describing them as beings with elongated limbs, luminous eyes, and a mysterious aura surrounding their presence. The aliens were said to move with a grace and fluidity that defied human capabilities.
Multiple videos and photos flooded social media platforms, documenting the alleged extraterrestrial encounter. These digital snippets depict peculiar entities strolling casually alongside enthusiastic onlookers and bemused pedestrians. As news of the sightings spread, crowds began to gather, hoping to catch a glimpse of the enigmatic visitors from beyond our planet.
Local authorities were initially skeptical of the claims, attributing the sightings to an elaborate stunt or publicity stunt staged by the city's entertainment industry. However, as more reports poured in from reliable witnesses and the evidence continued to mount, officials decided to launch a formal investigation into the matter.
The Las Vegas Metropolitan Police Department, in collaboration with experts from various scientific disciplines, has initiated an inquiry to discern the authenticity of the sightings. Specialized teams have been dispatched to collect and analyze available data, including the videos and photographs captured during the alleged extraterrestrial encounter.
The scientific community, too, has been captivated by the developments in Las Vegas. Renowned astrophysicist Dr. Elizabeth Cohen expressed her fascination, stating, "If these sightings turn out to be authentic, it could be an extraordinary milestone in our understanding of extraterrestrial life. We must approach this with an open mind and employ rigorous scientific methodologies to investigate this extraordinary phenomenon."
While speculation is rife, it is important to remain cautious and avoid jumping to conclusions. The investigation is ongoing, and experts urge the public to refrain from spreading misinformation or engaging in panic-inducing behaviors.
The alleged alien sighting has reignited the age-old debate surrounding extraterrestrial life and its potential interactions with humanity. Las Vegas, often associated with extravagant spectacles and the unexpected, has now become the stage for a real-life sci-fi drama, capturing the imagination of both believers and skeptics alike.
As the world awaits the outcome of the investigation, the streets of Las Vegas continue to buzz with excitement and anticipation. Tourists and locals flock to the Strip, hoping for a glimpse of the mysterious visitors or any updates on the ongoing investigation.
Whether this encounter is a pivotal moment in our understanding of the universe or an elaborate ruse remains to be seen. Nevertheless, for now, Las Vegas remains a magnet for both earthly delights and the possibility of otherworldly encounters.
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