The Viking landers were the first spacecraft to conduct experiments on Mars

Planetary exploration and the search for extraterrestrial life kicked off with Viking

NASA's Viking 1 and 2 missions revealed Mars' geological activity and potential for past life through their evidence of past surface water. Viking 1 held the record for the longest Mars surface operation until the Opportunity rover surpassed it in 2010.

Read the NASA overview of the results of Viking’s biological experiments on Mars

Three experiments on the Viking 1 and 2 landers searched for signs of metabolic activity in soil samples, indicating the presence of microorganisms. No definitive evidence of life was found in any experiment or lander imaging.

View the first photos ever taken from the Martian surface

NASA's Viking 1 landed on Mars on July 20, 1976, with Viking 2 following on September 3, 1976. The two captured 4,500 images of Mars as the first spacecraft to land and transmit data from the Red Planet successfully.

Viking established entry, descent, and landing methods for future planetary visits

The most significant engineering challenge was slowing the Viking lander, which would move through space at nearly 29,000 kilometers per hour before reaching Mars. This required the invention of supersonic parachute technology, which is still used today.

Explore the Spirit and Opportunity Martian rovers

The twin machines were tasked with studying the geology of Mars to identify evidence of past water activity, determine the composition of minerals, rocks, and soils, and perform "ground truth" experiments to calibrate and validate observations made by Mars orbiters.

Congress settled for the Viking program after canceling the Voyager Mars program

NASA's proposed Voyager missions to Mars and Venus in the 1970s were canceled due to budget cuts and the Apollo 1 fire. The Viking program's smaller scope—focused on data collection—was the economically viable alternative to manned Mars mission proposals.

Explore a timeline of every mission to Mars through 2020

The US has conducted the most missions (23) and has the highest success rate (74%), followed by Russia (18 missions at 5%). The first successful orbiter was Mariner 4, while Viking 1 was the first successful lander.

View an interactive collection of historical documents from the Viking project

This collection includes original mission bulletins, engineering and planning documents, and interview segments from more than 80 Viking team members who made the historic exploration of Mars’ surface by a lander possible.

The USSR’s Venera program made the only successful landings on Venus

While the Soviet space program is famous for launching the first satellite and human into orbit, its most extraordinary feat was the Venera missions—probes that captured data, images, and audio from Venus’s brutal surface. No other nation has repeated the achievement.

Explore a timeline of NASA's exploration of Mars

NASA has studied Mars extensively over 60 years using telescopes, orbiters, and rovers. From April 2021 to January 24, the Ingenuity helicopter completed its technology demonstration objective by flying more than 17 kilometers above the Martian surface.

The first flight on Mars carried a piece of the Wright plane with it

In April 2021, the solar-powered helicopter Ingenuity—attached to NASA’s Perseverance Mars rover—flew in what became the first controlled flight on a planet other than Earth. Carried with it was a piece of fabric from the famous 1903 Wright Flyer, a symbol of Ingenuity’s continuation of the Wright tradition.

NASA uses extreme Earth environments to prepare for space exploration

Analog missions in volcanic terrains and craters mimic Martian and lunar environments. Crew members operating in these missions, including at sites in Utah, Nevada, Arizona, and Hawai'i, test suits and specialized space instruments under simulated conditions.

How NASA measures marsquakes

Most probes sent to other planets and asteroids focus on surface phenomena, but NASA's InSight Lander is interested in looking deeper. Studying marsquakes as well as the red planet's crust and core, InSight provided four years of insight into how the rocky planets of the inner solar system formed.

A four-billion-year-old meteorite reignited the debate about life on Mars

Recovered from Antarctica in 1984, ALH84001 contained organic compounds, magnetite and iron sulfide grains of potential biological origin, and features that resembled fossilized bacteria. With technological advancements, scientists found abiotic origins for these features in the following decades.

The European Space Agency placed a lander on the surface of a comet in 2014

Launched in 2004, the Rosetta spacecraft performed three flybys of Earth and one of Mars as gravitational slingshots to gain the necessary velocity to successfully place the Philae lander module on comet 67P/Churyumov-Gerasimenko. Philae achieved a soft landing only after bouncing twice from failed deployments of its anchoring harpoons.

The team responsible for the first interplanetary sundials included Bill Nye

While reviewing designs for instruments to be carried by future Mars rovers, Nye suggested adapting the function of a calibration tool, which would be used by the Spirit and Opportunity rovers to help calibrate the brightness and color of their panoramic cameras on the Martian surface.

Exoplanet atmospheric gas patterns may indirectly provide evidence for life

When searching for life beyond the solar system, scientists first determine the range of distances from a star that liquid water—believed to be essential for life—can be found. Within this habitable zone, the presence of specific molecules in an exoplanet's atmosphere—detectable through spectral analysis—can indicate the presence of living things known to produce those compounds.

NASA's ESCAPADE mission will study Mars' atmosphere

The $80M mission—a collaboration between private companies, universities, and NASA—sent two copy machine-sized orbiters on a Blue Origin rocket to the red planet to study its magnetic field and atmospheric loss.

Martian skies and sunsets resembled Earth's hundreds of millions of years ago

Evidence suggests that Mars has had a thicker atmosphere, which included greenhouse gases, and a magnetic field in its past, resembling Earth's current composition. After losing its magnetic field—the protection from solar wind—the atmosphere and its associated atmospheric phenomena gradually disappeared.

Perseverance captures an aurora on Mars

The Perseverance rover captured the first visible Martian aurora, offering insights into Mars's atmospheric interactions. A coronal mass ejection likely triggered the aurora since the planet lacks a global magnetic field.

Besides Earth, Mars is the only possibly habitable planet in our solar system

Sending humans to Mars in the following decades poses significant challenges, from the vast distance covered to get materials there to powering technology during weekslong dust storms. Research is ongoing to develop life support systems that can regenerate or recycle consumables.

A prototype greenhouse for Biosphere 2 is now part of a test habitat for Mars

The Space Analog for the Moon and Mars combines the Test Module greenhouse with a workshop, kitchen, common area, sleeping quarters, and a yard that mimics lunar and Martian surfaces. A blind crew member in SAM’s first mission, Inclusion I, helped assess accessibility in potential future space habitats.

The Polaris Dawn program led to the first commercial spacewalk

As part of the Polaris program, this first mission included a crew comprising astronauts and SpaceX engineers, who conducted scientific experiments and cultural outreach, such as raising funds for St. Jude Children's Research Hospital.

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

Sputnik 1—launched in 1957—was Earth's first artificial satellite

Its launch accelerated US investment in the Space Race amid fears the Soviet Union had the technology to launch intercontinental nuclear warheads. It would be followed by Sputnik 2, which carried the first living being—a dog named Laika—to orbit.

A history of water on the moon

Is there water on the moon? In 2020, NASA's SOFIA mission confirmed the existence of water on the sunlit area of the lunar surface. Early astronomers mistook the dark spots on the Moon for oceans, but they are actually plains of dark, lava-produced...

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

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

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.'

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

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.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

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.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

The first robot in literature may have been a 'mechanical man' in 1907's 'Ozma of Oz,' a book in L Frank Baum's 'Wizard of Oz' series.

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 19th-century painters of the Hudson River School were among the first American romantics, with portraits that displayed the natural beauty of the young country.

The Beatles' US label rejected the band's first two singles, 'Please Please Me' and 'From Me to You,' with one executive calling the band 'dead in the water.'

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

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