Space Coast bustling with 4 crew launches on tap from SpaceX, Boeing

The National Aeronautics and Space Agency, or NASA, was founded on July 29, 1958, when President Dwight D. Eisenhower signed the National Aeronautics and Space Act, one year after the Soviets launched Sputnik 1, the world's first artificial satellite. NASA was designed from the start to push the bounds of space exploration with research into aerospace and aeronautics as well as with a civilian space program.

In honor of World Space Week, which takes place Oct. 4-10, Stacker compiled a list of key astronomy and astrophysics terms from a variety of authoritative science communication sources, including Crash Course: Astronomy, How Stuff Works, and International Comet Quarterly.

As the agency unrelentingly forged a path toward astronomical discovery, NASA also invented a number of technologies that we use in our everyday lives. These include artificial limbs, LASIK surgery, improved water filtration, camera phones, freeze-dried foods, memory foam, LED lights, and even the Dust Buster. In fact, it was a NASA scientist who invented the Super Soaker squirt gun.

Keep reading to learn the terms that are commonly used in this fascinating field.

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Similar to how raindrops hit a moving car window as if from an angle, an aberration of light is the phenomenon where stars or other celestial bodies appear from Earth to be slightly off from their true position. This happens because of motion—specifically, the interaction of the Earth's movement with the speed of light causes this confusing phenomenon.

Alpha Centauri is the name of the closest star system to earth. It comprises two main stars, Alpha Centauri A and Alpha Centauri B, as well as the closest of the three stars, Proxima Centauri. In 2016, astronomers found an Earth-sized planet orbiting Proxima Centauri, later named Proxima b. While this planet shows signs that life could exist, astronomers are still unsure how habitable it is. 

Also known as M31, this galaxy is the closest to the Milky Way, where the Earth exists. Andromeda Galaxy has a similar structure to the Milky Way; it is spiral in shape and has a large density of stars, dust, and gas. Because of its proximity, it is the only galaxy that can be seen from Earth with the unaided eye, particularly on fall and winter nights. 

Asteroids are chunks of rock or metal that used to be parts of other small planets that have broken off due to a collision in space and now orbit the sun. The word asteroid means "star-like," referring to their emission of light. Asteroids can be lumped into orbital groupings called families and form into an asteroid belt. 

A barycenter is the common center mass around which a solar system orbits. While it has become common knowledge that planets orbit stars, it is, in fact, the barycenter that both stars and planets orbit around. Our solar system's barycenter is constantly changing position based on where each of the planets is in its orbit, ranging from being near the center of the sun to being just outside its surface. 

The Big Bang Theory is a model describing the origin of the universe. It explains how the universe expanded from a high-density, high-temperature state into the cosmos we see today. Although there are alternative theories, this is the most widely recognized theory of how the universe began.

Binary stars are systems that only contain two stars that orbit together. Together, they orbit a common center of mass. There are two types of binary stars: wide binaries and close binaries. Wide binaries orbit with a significant distance apart from each other, causing them to have little effect on each other. Close binaries orbit closely and actually can acquire material from one another.

Made famous by Einstein's theory of general relativity, a black hole is the small dense core remnant of a dead star. Since the density of this core is more than about three times more than the density of the sun, the strong force of gravity produces a black hole. 

A brown dwarf is born from a collapse of gas and dust, similar to stars. This collapse creates a large amount of energy that gets trapped in a ball of material. The energy emits light from within for tens of millions of years, becoming dimmer as time passes. 

A celestial sphere is a tool used in spherical astronomy. It is a sphere with a large radius that is concentric with Earth. The sky surrounding the Earth is projected on the sphere, which is helpful for astronomers when they are attempting to plot positions in situations where distances aren't important. 

Besides being a beautiful phenomenon rarely visible from Earth, comets are icy, frozen balls of gas, rock, and dust. Comets gain their trademark bright glow by emitting gas as their orbit passes close to the sun, sometimes even resulting in a glowing tail.

One of the first things we learn about space is its many constellations. From Orion and his belt to the mythical Seven Sisters and the Big and Little Dipper, constellations map out a group of stars that form shapes in the sky. Explorers first used constellations to map directions as well as a tool for storytelling.

Like the cosmic mystery its name evokes, dark energy is hard to define. The easiest way to think of it is a property of space that accounts for an expanding universe. The universe's "empty space" may still have its own, dark energy. However, scientists are still trying to pin down the properties of this dark energy that makes up most of the universe.

Somewhat similar to dark energy, dark matter also covers a large chunk of the universe and remains quite mysterious to scientists. The main difference is that dark matter explains more about how groups of objects in the universe function together. Though scientists have a greater understanding of what dark matter isn't than what it is, a leading theory posits dark matter is made from exotic particles like axions or Weakly Interacting Massive Particles (WIMPS). 

Also known to most as the Doppler effect, the Doppler shift explains the phenomenon of the change in frequency of a wave in relation to an observer. This can be observed when an ambulance drives past you and the volume of the siren doesn't quite match with the proximity of the ambulance to you. 

An eclipse refers to one body in space moving into the shadow of another body. Eclipses can exist in two forms—solar and lunar—depending on the orbit of the Earth and moon. With a lunar eclipse, the moon moves behind the Earth. During a solar eclipse, the moon orbits between the Earth and the sun.

During an equinox, Earth experiences an even 12 hours of daytime and 12 hours of nighttime. This occurs twice a year: The March equinox marks spring's arrival in the Northern Hemisphere and Fall in the Southern Hemisphere. The September equinox ushers in the fall's arrival in the north and spring in the south.

Escape velocity is the speed that an object needs in order to escape a planet or moon's gravitational pull. For example, the escape velocity for a spaceship to leave the surface of Earth is about 25,000 miles per hour. 

When planets exist beyond our solar system and orbit a star other than the sun, they are called an exoplanet. Exoplanets are extremely hard to see, as they are often hidden by the glare of the star they orbit. Because of that, the first exoplanet was not recognized until 1992.

Named after Italian-American physicist Enrico Fermi, the Fermi paradox is a theory using statistical analysis to postulate why we have yet to see signs of life on other planets within our galaxy. The paradox assesses the likeliness that there are similar planets to Earth within the Milky Way, and likely have the ability to support life, yet no signs of life have been found which means it's a paradox.

We all know that we live in the Milky Way galaxy, but what exactly is a galaxy? A galaxy is a wide-ranging mix of dust, gas, stars, and various solar systems brought together by a singular gravitational pull.

A gamma-ray burst is the most violent type of explosion in the universe. The explosion itself emits more energy in 10 seconds than the sun will emit in its lifetime. When it happens, it's the brightest source of light in the observable universe. Satellite evidence suggests gamma-ray bursts are the result of matter collapsing into black holes.

Based on the Latin word for "weight," gravity is a natural phenomenon where things with mass or energy are drawn toward its center. The force of gravity is what keeps us planted on Earth's surface and also keeps the Earth orbiting the sun. 

A hypergalaxy consists of one large dominant galaxy surrounded by various smaller tertiary galaxies. The Milky Way and our neighboring Andromeda galaxies are both hypergalaxies.

A light-year is as simple a concept as its name suggests. It is an astronomical distance that measures the distance that light travels in a year. One light-year roughly equates to 6 trillion miles.

Understanding Magellanic clouds has become a propelling source of understanding distant galaxies. They consist of two irregular galaxies that orbit the Milky Way. Orbiting about 200,000 light-years away, the Magellanic clouds are formed by the Large Magellanic Cloud and the Small Magellanic Cloud.

Magnitude refers to a mathematical measurement for something's size or extent in comparison to other similar objects. In astronomy, magnitude is a unitless system used to measure the varying degrees of brightness of objects in the sky. Greek astronomer Hipparchus introduced the concept of magnitude for classifying stars in 129 B.C., referring to the brightest stars in the sky as "first magnitude."

A meteor is a rocky object or asteroid that vaporizes when entering the Earth's atmosphere. They're often called "shooting stars" and provide a beautiful glowing tail as they enter the atmosphere. Next time you see one, be sure to make a wish upon a meteor! 

The Earth's galactic home, the Milky Way is a spiral galaxy that is constantly rotating. The Milky Way contains a high amount of dust and gas wrapped around the central galactic bulge. The galactic bulge contains a dense amount of dust, gas and stars. And within that bulge, exists a large black hole (see slide #8). Our solar system lies about 30,000 light-years from the galaxy's center.

The moon is a heavenly body that orbits the Earth and happens to be the easiest object to spot in the night sky. As the moon orbits our planet, we see it go through "phases," where at different times different proportions of the moon's surface are visible. These phases have guided time since the beginning of humanity. The calendar month roughly replicates the moon's orbit of the Earth. 

A nebula is a large cloud of dust and gas in space that is produced when a star dies. The gas and dust eventually clump together into a mass large enough to form its own gravity. Nebulae can also be places for new stars to form and are sometimes referred to as "star nurseries."

The Nebular hypothesis is the most widely accepted theory of how our solar system was born. The theory itself was born during the Scientific Revolution from the 16th to 18th centuries. The theory's essence states that our solar system was birthed from a nebula billions of years ago. The theory has also been applied to how all stars came to be.

Neutron stars are small, but very dense objects that are birthed by the explosive death of a giant star. Neutron stars can exist in two states. The first is a pulsar, which emits a narrow radiation beam. The second is a magnetar, which has a powerful magnetic field that has the force to distort atoms.

Named after astronomer Jan Oort whose theory about a cloud comprising a shell of icy objects existing beyond the Kuiper Belt, or the region that exists in our solar system beyond Neptune, could be responsible for the long-term comets visible from Earth (like Halley's). The cloud is theorized to comprise the remains of disc materials of planets and the sun.

In short, an orbit is the gravitationally curved trajectory of an object in space. In other words, an orbit is the circular motion in which objects in space travel due to gravity's pull. For example, the moon orbits around the Earth and the Earth orbits around the sun in a circular motion. An object that orbits another is called its satellite.

Measuring using parallax involves estimating the distance of nearby celestial objects by measuring movement against more distant celestial objects. This method is often used when measuring distances of neighboring stars, called stellar parallax. 

Quasars are large distant objects in space that are powered by large, powerful black holes. They tend to shine so brightly that their light eclipses the old galaxies that they exist within. They are capable of emitting thousands of times more energy than the Milky Way emits.

A red giant is a star that is reaching its final days and approaching death. If a star has turned into a red giant, the star is in the last states of its stellar evolution and expands. Our own sun will eventually expand and turn into a red giant—but not for a few billion years. 

Red shift and blue shift explain how light changes wavelength as objects in space move closer or farther from each other. As an object moves away from us, the light is shifted towards the red end of the color spectrum. In turn, as it moves closer, the light shifts towards the blue end of the spectrum. Along with blue shift, red shift is hugely valuable in understanding the universe's expansion.

A solar system is a gravitationally bound system of a sun and the objects that orbit it. That includes the bodies that orbit the objects orbiting the sun. For example, our solar system contains the sun, the planets that orbit it, as well as moons and other objects that orbit them. 

Solar wind is a wind streaming solar particles and plasma from the sun. As a solar wind carries charged particles from the sun towards the Earth could have catastrophic effects for Earth's habitants. But don't worry, Earth's magnetic field provides a pretty sturdy shield against any of these negative effects. 

Sometimes referred to as the "noodle effect," spaghettification is when the extreme tidal forces stretch out objects to be long and thin like a noodle. This effect can also be caused by the immense gravitational pull of a black hole.

Other than serving as beautiful guiding lights in our sky, stars are astronomical objects that are composed of gas that pulls itself together with its own gravitational pull. Nuclear fusion at the star's core creates the light that stars emit. 

In the same way that planets can be gravitationally bound to the sun, causing them to orbit it, stars can also cluster together due to gravity. Two types of star clusters can be determined: globular clusters and open clusters. Globular clusters are tight clusters of thousands of older stars, whereas open clusters are made up of a few hundred very young stars.

A supernova is the largest explosion that can be seen with the human eye. A supernova occurs as the last step of a dying massive star that emits an extremely bright light. This occurs in the death of a star at least five times the mass of our solar system's sun.

A telescope is the signature tool of astronomers to see far objects out in space in further detail. Today, telescopes are designed with curved mirrors that gather light from the sky and concentrate it so that far away objects are visible.

The theory of relativity was developed by Albert Einstein in 1905 and includes both theories of special relativity and general relativity. The theory determines that the laws of physics are the same for all non-accelerating observers and was monumental in introducing a framework for space and time.

Tides are the rise and fall of sea level that is caused by the gravitational pull of the moon and the sun. They are one of the most reliable phenomena in the world. The difference between high and low tide is called the tidal range.

A white dwarf is a relatively small star that is about the size of a planet that is very dense. It is essentially a star that has exhausted all of its nuclear fuel from within. It expels most of its outer material, leaving a white-hot core that cools over the next billion years. 

And lastly, we have landed at the universe. A loaded definition that has flummoxed scientists for generations, a universe contains billions of galaxies and even more stars along with their planets, moons, asteroids, comets, dust, and gas, all of which exists swirling around in the massive thing we call space.

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The universe is nearly 14 billion years old. Human existence makes up a tiny fraction of that time. If the history of Earth was made up of 24 hours, humans came into the picture just before 11:59 p.m.—and we've spent much of that time fascinated with space.

For so long, we have posited theories and done our best to reach the most distant corners of the universe. Sixteenth-century Mesopotamians envisioned space as a cosmic ocean. While under the reign of the Roman Empire, Ptolemy theorized a geocentric universe. In 2015, new evidence emerged supporting the existence of water on Mars, and more recently, space tourism has been a hot topic of conversation. People at all points in history have had ideas about what lies beyond the sky and have wanted both to understand and see it for themselves.

In honor of World Space Week, Stacker curated a gallery of groundbreaking NASA missions.

In the modern world, NASA is at the forefront of space exploration, making knowledge of the great unknown even more possible. Founded in 1958 and headquartered in Washington D.C., NASA quickly changed the course of both robotic and human spaceflight. Since its creation, the agency has put people on the moon, created new windows into viewing the universe, and discovered extrasolar planets, among other things. And as it turns out, the people doing all this incredible work are a little more down-to-Earth than the general public may believe. While some might be geniuses, they're also simply curious human beings.

The forthcoming images depict some of NASA's most profound achievements and capture these missions in a way that is at once visually profound and scientifically meaningful. Read on to learn about some of the most incredible moments and missions in NASA history.

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In 1958, the launch of Explorer 1 marked a crucial turning point: this was the first time the United States succeeded in launching a satellite into space. The Soviet Union had launched Sputnik 1 in late 1957, and Explorer 1 showcased the fact that the United States was very much a contender in the space race. Explorer 1 transmitted signals to Earth for just under four months and was destroyed years later, in 1970, when it reentered Earth's atmosphere.

Before NASA put anyone on the moon or even sent anyone into space, it needed to create and test a spacecraft that was up to the task. Thus, the Saturn V was born. This rocket, the kind that eventually would carry Neil Armstrong and Buzz Aldrin to the moon, was tested in stages throughout the 1960s and underwent its first full unmanned test flight in 1967, becoming the first-ever launch from the Kennedy Space Center in Florida.

Testing an entire rocket at once via a launch—rather than testing various aspects incrementally—was a novel approach, and then-Space Center Director Dr. Kurt H. Debus commented afterward that it "went extremely well."

By October 11, 1968, when Apollo 7 launched from Cape Canaveral in Florida, humans had already spent some time in space—the first among them being Yuri Gagarin of the Soviet Union. However, Apollo 7 orbited Earth 163 times over nearly 11 days, making it the longest trip thus far and breaking additional barriers by being the first manned spaceship to broadcast live on national TV. The successful goal of this mission was to both test the ship's equipment and to ensure that the three crew members could survive a trip this long.

Some may think Christmas with the in-laws is tough, but the crew of Apollo 8, who spent their 1968 Christmas in space, would likely beg to differ. The Apollo 8 mission was intended to test both the spacecraft and the crew in an orbit between the Earth and the moon (referred to as cislunar), and an orbit around the moon , which had never before been done. The mission went well, proving the technology new to this spacecraft, such as a combined forward hatch, was in good shape and ready for further use and development.

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While Apollo 8 successfully orbited the moon, it did not land, and additional testing was required to ensure that astronauts could visit the moon and return home safely. Enter the 1969 Apollo 9 mission, in which a crew tried out a piece of technology crucial to this goal: the lunar landing module. The mission was a success, and the crew could reattach the landing module in space, proving that a trip to the moon was not far off.

Often referred to as the "dress rehearsal" for the first lunar landing, the 1969 Apollo 10 mission essentially went through the motions of a moon landing, including detaching the lunar lander from the command module and putting it through the first portion of a descent, without actually touching down. The lunar lander and command module are respectively—and charmingly—referred to as Snoopy and Charlie Brown. Though everyone returned safely, the crew experienced a moment of panic when human error led the lunar module to spin wildly out of control (and the crew to shout a few choice expletives).

Ladies and gentlemen, the moment we've all been waiting for: on July 16, 1969, a Saturn V rocket carrying Neil Armstrong, Michael Collins, and Buzz Aldrin launched from Kennedy Space Center. Four days later, Armstrong became the first human being to set foot on the moon. A new documentary about this event has shed light on some forgotten moments of the mission, such as Neil Armstrong taking the time, in a live TV broadcast during the crew's return to Earth, to pay homage to the technicians and engineers who built the 363-foot rocket that would make history. Eight years after former President John F. Kennedy declared the lofty goal of putting a man on the moon, it was finally a reality.

A few short months after the Apollo 11 mission put the first two men on the moon, the Apollo 12 mission followed suit. On November 19, 1969, Charles Conrad Jr. and Alan L. Bean became the third and fourth souls to set foot on the lunar surface, spending 32 hours there while third crew member Richard F. Gordon, II stayed on board the spacecraft. Mission goals included collecting data and samples from the lunar surface, setting up the Apollo Lunar Surface Experiments Package (which would be left there to gather additional information), and checking on Surveyor 3, an unmanned spacecraft that had landed there two years earlier.

Houston, we have a problem: While this widely known phrase is not entirely accurate (crew member John Swigert actually said, "OK, Houston, we've had a problem here"), it still summarizes what happened during the Apollo 13 mission. This mission was intended to be the third moon landing, but that goal had to be aborted when an oxygen tank exploded 56 hours into the flight. The three men on board—Swigert, Fred Haise, and Jim Lovell—were then forced to take shelter in the lunar module and quickly assemble an adapter that would make the air breathable, thus proving the possibility of a safe return to Earth even in the face of harrowing danger.

Part of Apollo 13's objectives had been to land for the first time on a particular area of the moon known as Fra Mauro, a crater named for the 15th-century Italian geographer. Since Apollo 13 never landed, Apollo 14—which launched in early 1971 and carried a three-person crew of Alan Shepard, Stuart Roosa, and Edgar Mitchell—took over the goal of the Fra Mauro landing. After takeoff, the spacecraft struggled and experienced five failed attempts at connecting the command ship with the docking ring of the landing craft, but ultimately succeeded and completed the mission.

The July 1971 Apollo 15 mission was the fourth mission to put human beings on the moon. This mission marked the revolutionary debut of the lunar roving vehicle—also known as a "moon buggy"—a four-wheeled, open-air vehicle designed to function with the moon's gravitational pull, thus enabling astronauts to observe a wider range of the lunar surface in a single visit. One aim of the trip was to take more photographs than in prior visits, so the crew of this mission traveled with a variety of cameras to capture scenes during every part of the journey.

Beginning on April 16, 1972, the Apollo 16 mission lasted just over 11 days and carried the three-person crew of John Young, Thomas "Ken" Mattingly, and Charles Duke. Young and Duke set foot on the moon's surface and spent over 20 hours there collecting, in an amazing feat, over 200 pounds of lunar samples. Duke also made history by leaving something behind: a family photo with this message written on the back: "This is the family of astronaut Charlie Duke from planet Earth who landed on the moon on April 20, 1972."

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Apollo 17, which launched on December 7, 1972, marked the last time humans set foot on the moon; however, the legacy of this mission is still very much alive. NASA recently announced it would open a collection of lunar rocks from Apollo missions 15, 16, and 17 that had never been studied in full. The latter mission alone brought back 250 pounds of rocks. These samples were preserved for a time when more advanced technology could delve deeply into the clues they may hold, and the time to dig in has finally come.

The journey of Pioneer 10, a space probe that launched from Cape Canaveral on March 2, 1972, was filled with firsts. At the time, NASA was gearing up to take advantage of a rare alignment in the solar system that would allow for a "Planetary Grand Tour"—meaning a group of spacecrafts could visit multiple planets in one trip. To prepare for this journey, Pioneer 10 was sent on a data-gathering mission and became the first spacecraft to reach Jupiter and the first to leave the inner solar system.

Pioneer 11 served as a companion probe to Pioneer 10 and was launched into space in 1973. Pioneer 11's journey marked another important first for NASA: this probe was the first to encounter Saturn, and it was also able to send back amazing images of Jupiter's polar regions. The spacecraft experienced a few technical setbacks and failures on its outbound journey but overcame them and made such discoveries as an additional ring around Saturn. The last contact with this spacecraft occurred in late 1995.

The central goal of NASA's 1970s Viking missions was to gather images of and data pertaining to Mars, as knowledge of the planet was slim. The Viking project proved a huge success, producing some 50,000 images of Mars and disproving the theory that the Martian sky was blue, similar to that of Earth— it's actually pinkish during daytime. Viking landers could also touch down and analyze Martian soil and atmosphere, a huge stepping stone in scientific understanding of this planet.

The space probe Voyager 2 was sent into space in 1977, and in late 2018 it exited the heliosphere—the region of space that surrounds the sun and is impacted by its magnetic field—and officially went interstellar. In the decades preceding this monumental moment, Voyager 2 encountered and photographed Jupiter, Neptune, Uranus, and Saturn; it is the only probe to face the latter two planets. Voyager 1 went interstellar in 2012, and now both probes are on a mission to send back information about what lies beyond the solar system, though they are still many thousands of years from reaching the stars for which they have set course.

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Skylab, NASA's first space station, was made out of a component of a Saturn V rocket during a time of NASA budget constraints. It launched unmanned in May 1973. The goal was to test the viability, for the first time, of a space station a crew could inhabit for extended periods to conduct scientific research; in fact, several crews (one of which included Charles Conrad, a member of Apollo 12) visited and occupied the station during its time in space. Skylab's return to Earth became an international media spectacle, as NASA could not pinpoint the exact moment when or location where the craft would crash back through the atmosphere.

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NASA's Space Shuttle Program—in effect from 1981 to 2011—marked a huge scientific stride in creating the first effectively reusable spacecraft. The program created a fleet of five spacecraft during its three-decade run, and before Space Shuttle Challenger's tragic end, it carried Sally Ride, the first U.S. woman in space. Space Shuttle Discovery successfully carried 184 men and women to space and back and spent 365 days in space before it was retired in 2011.

For much of the Cold War, the United States and the former Soviet Union used space to compete against one another, but the Shuttle-Mir program noted a great shift in this dynamic. The program was a U.S.-Russia collaboration, comprising U.S. shuttles and astronauts visiting the Russian space station, Mir. When the U.S. space shuttle Atlantis docked at Mir in 1995, history was made in more ways than one: The U.S. and Russian spacecraft together formed the biggest man-made satellite, and the trip itself made up this country's 100th human space mission.

On July 23, 1971, Landsat 1 (originally named the Earth Resources Technology Satellite) was launched into space. The goal of the Landsat program was to obtain extensive satellite imagery of Earth's terrain. Today, both Landsat 8, which began operating in 2013, and Landsat 9, which was launched in 2021, are active and functional. The program was heavily opposed at the start due to budget restrictions and the U.S. Department of Defense's fear that such photography would negatively affect the confidentiality of the missions. But it was ultimately funded and became a successful and valuable program.

The Hubble Space Telescope is named for Edwin Powell Hubble, a hugely important 20th-century American astronomer who discovered and proved the existence of galaxies beyond the Milky Way. The telescope was launched into orbit in 1990 and has since broken barriers through its unique ability to capture and transmit images of space. The telescope is used for extensive scientific research projects, such as the Frontier Fields program, but members of the public can also apply for observation time.

Chandra X-ray Observatory, launched by NASA in 1999, is a telescope designed for detecting X-ray emissions in space. These emissions occur in the universe's hottest regions, where stars explode, and Chandra has been groundbreaking in its ability to capture images of such phenomena. The telescope captured images of a 2019 galactic storm in a distant galaxy in a cosmic structure known as the "Teacup," located over 1 billion light years from Earth.

The Spitzer Space Telescope, which launched in 2003 and retired in 2020, was an infrared telescope that has allowed scientists visual access to previously unseen regions of the universe. The telescope is made up of two main components: the spacecraft itself and the cryogenic telescope assembly. It has produced striking images of brown dwarfs, molecular clouds, and more. Spitzer is notable for its role in scientists' ability to identify exoplanets and has given insight into galaxies over 13 billion light-years from Earth.

If you don't enjoy spending extended periods of time with your coworkers, then a job on the International Space Station may not be for you. The Space Station, which launched into orbit in 1998, has been continuously inhabited, with crews generally staying on board for six months at a time. Many nations contribute crew members and scientific knowledge to the project, and the three members of the current Expedition 58—Oleg Kononenko, Anne McClain, and David Saint-Jacques—have been aboard since December 2018. This consistent presence of humans in space is groundbreaking in its own right and has allowed the scientific community to perform extensive experiments and gain knowledge about how humans can live in space.

Since 2012, the Curiosity rover for the Mars Science Laboratory has been stationed on the red planet, trying to provide an answer to one specific question: Was Mars ever able to support life, specifically microscopic organisms known as microbes? Mars Science Laboratory's mission is a subset of NASA's Mars Exploration Program, designed to study the habitability of Mars and determine whether the planet could one day be a home for humans. Through its success in shedding light on Mars, Curiosity is living up to its name, which was bestowed by a 12-year-old named Clara Ma, who won Mars Science Laboratory's essay contest in 2009.

Many spacecraft and brave astronauts have traveled the galaxy, but the Parker Solar Probe has embarked on a mission unlike anything that came before it. Launched in 2018, this probe will encounter unimaginably intense heat and radiation and is doing so to learn more about the sun's outer corona —the aura of plasma surrounding it. Another detail that sets the Parker Solar Probe apart from all other NASA missions is that it's the first to be named for a living individual: Eugene Newman Parker, a professor at the University of Chicago who theorized revolutionary concepts about how the sun emits energy.

Because of the dense layer of clouds that surrounds it, Jupiter maintains an environment that could shed light on the conditions in play when the solar system was first formed. This is the primary reason Juno is so important. Launched in 2011, it is the first probe to map Jupiter's structure so far below the clouds. It can sample the charged particles on the planet's poles, which have never been analyzed in such a way. Juno is the name of the Roman goddess who was able to see through clouds to check on her husband, Jupiter, which is perfectly fitting.

OSIRIS-REx's mission is no small undertaking. This spacecraft—and those behind it at NASA—seeks answers to questions such as where humans come from and why the universe exists as it does. OSIRIS-REx was launched in 2016 and is currently traveling back to Earth with samples from asteroid Bennu, which was chosen for this mission because of its size, composition, and proximity. The great feat of OSIRIS-REx is that it's on track to be the first mission to return an asteroid sample to Earth—on track for 2023.

Besides the great discoveries it provided, the Cassini-Huygens spacecraft also marked an act of unity in the name of science. This spacecraft, which traveled to Saturn carrying a probe known as Huygens, was a joint effort among NASA, the European Space Agency, and the Italian Space Agency. Cassini-Huygens' mission lasted 20 years, and in that time it made many critical discoveries, including revelations about the gravitational pull of Saturn's rings. Huygens also made the first landing on Titan, one of Saturn's moons. Perhaps most impressively, the Cassini-Huygens mission ended with a grand finale: In its last months, Cassini-Huygens dove through the gap between Saturn and its rings 22 times, creating a well of data about this previously unexplored region.

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Elon Musk's SpaceX is going where no private company has gone before: to space. The mission, representing the first astronaut trip to space since 2011, is part of NASA's Commercial Crew Program. The Crew Dragon spacecraft had astronauts Robert Behnken and Douglas Hurley on board when it took off from Launch Complex 39A in Florida on a Falcon 9 rocket on May 30, 2020.

NASA's Mars Exploration program launched the Perseverance rover in July 2020 as part of a multi-year program to collect organic samples and search for signs of life on the Red Planet. Fastened to the rover was a helicopter named Ingenuity, tasked with testing flight capabilities on Mars.

Perseverance has since revealed different types of rock present in Jezero Crater—including volcanic rock types that had, at some point, been in contact with water. Ingenuity has demonstrated that flight is, indeed, possible on Mars, having flown dozens of successful test flights. 

After many delays, the James Webb Space Telescope launched on December 25, 2021. The telescope uses infrared wavelengths to see further into the universe than we've ever been able to see before and is expected to provide invaluable information on the formation of galaxies in the early universe.

Since its launch, Webb has already sent back images of the oldest galaxy ever seen, clear views of the rings around Neptune, and detailed images of Jupiter. It has also aided in the discovery of carbon dioxide on an exoplanet.