The International Space Station is slowly falling due to atmospheric drag

The International Space Station is powered entirely by large solar arrays

Launched in 1998, its original solar panels were designed to withstand no more than 20 years of wear from temperature swings and micrometeoroid impacts in space. Replacement panels that roll out like carpets have since been installed.

Take a virtual tour of the International Space Station

The ISS is the largest human-made object in space. Its modules were meticulously connected by robotic arms and astronauts during slow, careful spacewalks, creating a structure with over eight miles of electrical wire.

Atmospheric drag is causing the Hubble Space Telescope to drift toward Earth slowly

Without interventions to boost the observatory to a higher orbit, Hubble is expected to fall to Earth's surface in the mid-2030s. In the meantime, the telescope is expected to continue to be productive by shifting its mode of operation to rely on a single gyroscope, down from three.

When retired, the International Space Station will undergo a controlled de-orbit

With plans to transition low-Earth orbit operations to private entities, the ISS is expected to be retired by 2030, using a SpaceX de-orbit vehicle. Although reentry will burn up most hardware, NASA intends for any surviving debris to fall into an uninhabited ocean area.

Space trash forced astronauts on the International Space Station to take shelter

An inactive Russian satellite broke up into nearly 200 pieces, prompting astronauts on the space station to take shelter in a docked spacecraft and a capsule that could be used to escape in case of emergency.

Visualize the impact of satellites and space debris orbiting Earth

According to NASA, approximately 9,000 metric tons of debris are orbiting Earth, with 70% of it located in low Earth orbit, where the Hubble Space Telescope and the International Space Station reside. The growing reliance on space-based platforms for modern technologies, including Starlink satellites, increases the risk of debris collisions.

Technologies developed for the ISS have brought benefits to people on Earth

About 93% of water used onboard the International Space Station is recycled through filtration and purification systems that have since been used in regions lacking access to clean water. Treatments to mitigate bone loss and muscle atrophy in astronauts can also help aging adults.

Watch a livestream of Earth from the International Space Station

The feed is made possible by the SpaceTV-1 camera system, which is live over 20 hours a day. Video replays are shown during routine loss of signal communications with the inter-satellite link relaying the video data.

Read about every visitor to the International Space Station

The US has sent the most astronauts to the ISS, with 170 visitors, followed by 64 from Russia, 11 from Japan, and nine from Canada. American astronauts Michael E. Lopez-Alegria and Peggy A. Whitson and Russian cosmonauts Yuri Malenchenko and Fyodor Yurchikhin have the most trips, with five each.

Emulating Earth’s light-dark cycle is important for astronaut health and safety

Astronauts aboard the International Space Station experience 16 daily sunrises, but scientists have learned to try to promote circadian rhythms by phasing through several light settings aboard the ISS to improve astronauts’ sleep and productivity.

Planets' high orbital speeds prevent them from falling into their host star

Although the gravitational force attracts a planet and the star it orbits around, the large speed the planet orbits with, which is acquired during its formation process, causes it to continuously miss the star as it orbits around it. This is analogous to theoretically throwing a baseball horizontally faster and faster until it's fast enough to orbit the Earth while attempting to fall to its surface.

In 2018, SpaceX launched a Tesla Roadster into heliocentric orbit for publicity

As of February 2023, the vehicle and its mannequin driver—dubbed "Starman"—have completed three and a quarter revolutions around the sun. One paper estimated that the car has a 22% chance of crashing into Earth within the next 15 million years.

Microgravity environments reduce muscle mass and bone density

Muscles that assist with balance and resistance to gravity are not subjected to their usual workload on the International Space Station. See the type of exercises that astronauts must complete for roughly two hours daily and learn why these movements are necessary to preserve astronauts' muscles, bones, and cardiovascular health.

Understanding why suction cups rely on Earth's atmosphere to work

When pressed against a surface, air is squeezed out of a sealed volume, causing the internal pressure to drop below the surrounding atmospheric pressure, and this imbalance creates the "sticking." For this reason, astronauts do not use suction cups or related technologies to stay on spacecraft during spacewalks.

Thermodynamics makes building data centers in space to cool equipment impractical

Rather than cooling via interactions with flowing cold air or water, data centers in space would dissipate energy primarily by radiation, in which an object at any temperature above absolute zero emits light. This method is much less efficient at cooling and would require hyperscale data centers to have radiator panels thousands of times larger than those on the International Space Station.

Space tourism rockets emit up to 100 times more CO₂ per passenger than airplanes

Rocket launches release significant amounts of water vapor, nitrous oxide, and rocket propellants, which generate greenhouse gases and air pollutants. High-altitude emissions can persist for years, affecting the ozone layer.

Astrobee is a free-floating robotic system helping with routine tasks on the ISS

Three cube-shaped robots use electric fans to fly through the microgravity environment of the International Space Station. They are equipped with cameras and sensors that allow them to "see" and navigate their surroundings to take inventory, document experiments, and move cargo.

Why the edge of Earth's atmosphere varies depending on which property is considered

As the distance from Earth's center increases, the planet's gravitational force weakens, causing it to gradually lose its ability to retain gases at the farthest edge of its atmosphere—the exosphere. At a height of approximately 200,000 kilometers (124,000 miles)—halfway to the Moon—the exosphere has so little density that it is indistinguishable from interstellar space.

Five hazards of human spaceflight

From space radiation to isolation, humans struggle when it comes to traveling and living in space. What does this mean for long-term spaceflight? This hour-long podcast episode attempts to answer that question while detailing five major spaceflight hazards.

The Space Launch System: NASA's most powerful rocket ever

The Space Launch System is intended to be the most powerful rocket ever built by NASA. Possible missions include returning to the moon and perhaps even reaching Mars. This speculative and mostly silent video uses animation to explore the inner workings of the SLS, showing it launching and in space flight.

Earth is constantly bombarded by material from space

Most of this matter is composed of small particles, with any smaller than 33 feet in diameter burning up in the atmosphere. Larger asteroids can reach the ground, and those larger than several thousand feet cause global damage, including earthquakes and tsunamis.

Earth's smooth, continuous motion as it orbits the sun prevents detectable motion

Although humans are sensitive to acceleration, Earth's nearly circular orbit around the sun and its slow spin relative to its size produce negligibly small, minimally changing accelerations. However, the changing seasons and the day-night cycle are evidence of Earth's movement through space, as verified by satellites and telescopes.

NASA's budget makes up less than 0.4% of total US spending

NASA's annual budget consists mainly of human spaceflight activities (50%) and robotics and scientific research programs (30%). It peaked at almost $70B in 1964 but has been below $30B since 1995, coming from discretionary nondefense funds.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Voyager spacecraft defied expectations and only powered down after 47 years in space

Originally built for a four-year mission, Voyagers 1 and 2 used a rare planetary alignment and gravity assists to reach interstellar space. With limited power and aging systems, they will continue to send data until the mid-2030s. (Some readers may experience a paywall.)

On April 12, 1961, Soviet cosmonaut Yuri Gagarin became the first human in space

In 1961, Soviet cosmonaut Yuri Gagarin became the first human to orbit Earth, deepening US fears of falling behind in the space race. Watch archival footage to see why the mission was such a historic turning point.

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

See the 25 of the best photos of auroras from around the world.

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Calculate how much of your tax dollars go to each federal program based on your income, filing status, and number of children

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

In 2009, the nation was gripped by the story of a missing young boy who was believed to be floating over Colorado in a homemade balloon, until it was revealed that he was at home the whole time.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time