On Oct. 21, 2008, the Indian Space Research Organization launched its first mission to the moon. The mission was named Chandrayaan-1, and it consisted of both an orbiter and an impactor.

Chandrayaan-1 launched from the Satish Dhawan Space Center on an Indian rocket called the Polar Satellite Launch Vehicle, or PSLV-XL. (Launch occurred at 8:52 p.m. EDT, though it was about 6:22 a.m. local time at the launch site on Oct. 22.)

It arrived in lunar orbit about three weeks later and dropped off the Moon Impact Probe, which crashed into the moon on Nov. 14. The rest of the Chandrayaan-1 spacecraft stayed in orbit, where it collected and transmitted data from the moon to Earth for about a year. The mission ended abruptly 14 months ahead of its planned end date when scientists lost contact with the probe.

Why it mattered

The Indian Space Research Organisation, or ISRO, had a lot riding on the success of Chandrayaan-1 moon mission, which marked the first-ever deep space mission by the Indian space agency. It was also the first mission to the moon for India, a country that hopes to launch its own crewed spacecraft and build a space station.

Chandrayaan-1 did more than just demonstrate that India's space program was capable of launching missions to the moon; it also returned some amazing science results, like evidence of water ice on the moon.

"In September 2009, scientists published results of data collected by the American M3 instrument which had detected absorption features on the polar regions of the surface of the Moon usually linked to hydroxyl- and/ or water-bearing molecules," NASA said in a mission overview.

The spacecraft carried 11 instruments to study the moon, five of them built by ISRO. The rest were experiments for the European Space Agnecy and NASA.

"In addition to the five Indian instruments, the spacecraft carried scientific equipment from the United States, the United Kingdom, Germany, Sweden, and Bulgaria," NASA said.

It took until Nov. 8, 2008 for Chandrayaan-1 to enter lunar orbit, where it stayed until contact was lost in August 2009, most likely due to a power supply failure caused by overheating.

"This was short of the spacecraft’s planned two-year lifetime, although ISRO noted that at least 95% of its mission objectives had been accomplished by then," NASA wrote.

India did not stop at the moon with Chandrayaan-1. In 2019, the country launched the Chandrayaan-2 orbiter, which carried the Vikram lander and Pragyan rover. Chandrayaan-2 reached lunar orbit successfully, but the Vikram landing failed.

The Chandrayaan-3 misson followed in 2023, which successfully landed a new Vikram lander and Pragyan rover near the moon's south pole. India plans to launch the Chandryaan-4 mission to return moon samples to Earth in 2028.

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On Oct. 20, 1970, the Soviet Union launched the Zond 8 spacecraft on a mission to the moon. This was the last mission in the Zond program.

After the first three Zond missions explored Venus and Mars, the next ones were circumlunar missions that flew around the moon before returning to Earth. Although there was no crew on board, the Zond spacecraft was designed with cosmonauts in mind.

The Zond missions served as test flights for the Soviet Union's plans to send cosmonauts to the moon. But those plans for crewed flights never came to fruition. This was partly because the U.S. had already put astronauts on the moon, but also because the Zond missions had a lot of technical problems.

Zond 8 was considered a success — even though its guidance system malfunctioned on the way back to Earth. The spacecraft still returned to Earth safely and splashed down in the Indian Ocean one week after it launched.

Why it mattered

While the Zond 1 and Zond 2 missions were launched toward Venus and Mars, respectively, the primary target of most Zond missions was the moon. At the time, the Soviet Union was embroiled in an ongoing space race with the United States to be the first on the moon with a human crew.

By the time Zond 8 launched on Oct. 20, 1970, that space race was lost to the Soviet Union. NASA and the U.S. had already landed astronauts on the moon twice with Apollo 11 and Apollo 12 (in July and November of 1969, respectively), and even peformed the first space rescue fo the Apollo 13 astronauts in April 1970.

While Zond 8 was uncrewed, it was a test flight of the Soviet Union's L1 spacecraft that was designed to fly a cosmonaut around the moon. It looped around the moon in a lunar flyby, approaching within 1,120 kilometers of the moon's surface at its closest point, according to RussianSpaceWeb.com.

Cameras on Zond 8 captured stunning views of the Earth and moon, recreating the iconic Earthrise views seen by Apollo 8 astronauts two years earlier in 1968.

Zond 8 ultimately splashed down in the Indian Ocean on Oct. 27, 1970 after a solar attitude sensor failed, sending it on a shorter, steeper reentry path during landing, according to RussianSpaceWeb.com. It was retrieved by a recovery ship, marking the end of the Soviet moon landing program. Russian would go on to develop a series of Salyut space stations, culminating in the long-lived Mir space station.

After decades without a moon probe, Russia did launch a new uncrewed moon lander in 2023. That Luna 25 mission failed and crashed into the lunar surface after an onboard engine controller malfunctioned. The country has pledged a return to the moon in 2027.

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On Oct. 19, 2016, the European Space Agency's ExoMars mission arrived at Mars!

ExoMars 2016 consists of the Trace Gas Orbiter and the Schiaparelli lander. The orbiter and lander traveled there together and separated on Oct. 16, three days before the orbiter entered orbit around Mars, and the lander touched down on the planet's surface. But something went wrong during the lander's descent, and it crashed into the ground.

Schiaparelli did not survive the accident, but the Trace Gas Orbiter is still functional. It is currently circling the planet, looking for methane and other gases in the Martian atmosphere that could be evidence for possible biological activity.

Why it mattered

ExoMars 2016 was a landmark mission for the European Space Agency and designed to be the vanguard of a two-flight ExoMars program to send an orbiter, lander and rover to Mars.

Launched in March 2016, ExoMars 2016 aimed to achieve two goals for ESA and Russia. First, the mission aimed to use the Schiaparelli lander to test landing techniques that would be vital on a planned ExoMars 2018 rover. Second, the mission would deliver a critical orbiter around Mars to study the planet's atmosphere and serve as a communications link for that future Mars rover.

In the end, ExoMars 2016 was just a partial success, with ESA officials calling it "96% successful." due to the loss of the lander.

While Schiaparelli separated smoothly from the ExoMars Trace Gas Orbiter spacecraft, it stopped communicating with Earth just 1 minute before its planned landing on Oct. 19. Photos from NASA's Mars Reconnaissance Orbiter at Mars later revealed what appeared to be its crash site and, nearby, its jettisoned parachute. Officials suspect Schiaparelli did not fire its descent thrusters as designed in order to slow itself enough for a safe landing. A data glitch was cited as its cause.

The Trace Gas Orbiter, meanwhile, continues to study Mars to this day and has spent 10 years and counting studying the Martian atmosphere.

The launch of ExoMars 2018, which includes the Mars rover Rosalind Franklin, was delayed by the Schiaparelli failure, as well as the loss of its Russian Proton rocket when ESA severed its partnership with Russia over that country's war on Ukraine.

The ExoMars rover is now expected to launch no earlier than 2028, with a landing on Mars expected in 2030.

In 2026, another country took aim at Mars on this day.

The Japan Aerospace Exploration Agency attempted to launch the ambitious Martian Moons eXploration mission (called MMX) to land a probe on the Mars moon Phobos and return samples to Earth.

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On Oct. 18, 1963, a cat went to space! Félicette was a French "catstronaut" who became the first and only feline to fly to space.

While the U.S. and Soviet Union were busy launching primates, dogs and humans, the French decided to join the space race by launching a cat. Félicette, a stray tuxedo cat from the streets of Paris, was a substitute for another cat named Felix, who somehow escaped on launch day.

So Félicette went where no cat had ever gone before. She boarded a French Véronique AG1 rocket and soared 130 miles above the Earth before safely parachuting back down.

Luckily Félicette made it home alive and well, unlike many of the other animal astronauts that flew during the space race.

Why it mattered

Félicette survived spaceflight, but was short of this world. She was euthanized two months after her recovery so scientists could study her brain.

A second cat was launched by the French on Oct. 24, but its flight did not go so well, veering off course. When the cat was found a day later, it was discovered it have died as a result of the journey. From there on, CERMA (Centre d'Enseignement et de Recherches de Médecine Aéronautique) changed its research to flying monkeys.

Félicette may have become a footnote to history had it not been for a crowdfunded effort to raise a statue in her memory nearly 60 years later. The sculpture was unveiled in 2019 at the International Space University in Strasbourg, France. European astronauts Helen Sharman, Paolo Nespoli and Reinhold Ewald were on hand for its reveal.

In addition to the memorial statue, Félicette has been memorialized on postage stamps issued by Chad and Comoros, both former French colonies.

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On Oct. 17, 2016, Orbital ATK (now Northrop Grumman Space Systems) returned to flight, successfully launching a cargo shipment to the International Space Station (ISS) after its previous cargo mission failed to launch.

The private spaceflight company was contracted by NASA to fly cargo to the ISS, and stakes were high for this launch. Orbital ATK's last attempt nearly two years earlier ended in a catastrophic explosion a few seconds after liftoff.

Despite some delays, the newly upgraded Antares rocket flawlessly blasted off into the night sky from NASA's Wallops Flight Facility in Virginia. Six days later, the Cygnus cargo spacecraft arrived at the ISS to deliver food, supplies and science experiments to the crew.

Why it mattered

For the International Space Station to be able to sustain a continuous human occupancy, periodic cargo deliveries are needed. Russia fulfills part of this requirement with its Progress spacecraft, and both ESA (European Space Agency) and JAXA (Japan Aerospace Exploration Agency) have contributed with their Automated Transfer Vehicle (ATV) and H-II Transfer Vehicle (HTV), respectively.

For its part, NASA contracted with Orbital (today, Northrop Grumman) and SpaceX to fly commercial resupply service missions. Both were needed to keep the U.S. operating segment of the station well supplied and with the science and research materials needed for the crew's work.

Below is a video of the explosion

Though adjustments can be made to go without one or more of these vehicles for a short period of time, the Progress, Cygnus and Dragon are key components of the ISS's continuous operation. So returning a vehicle to flight after a catastrophic exploration is important to well-being of the International Space Station program.

As it happened, Antares would fly another 12 times before having to stand down again to be redesigned, but that is for a different This Day in Space entry.

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On Oct. 16, 1975, NASA launched the first operational GOES satellite!

GOES-A was the first in a series of weather satellites that NASA jointly operated with the National Oceanic and Atmospheric Administration (NOAA).

The name is short for Geostationary Operational Environmental Satellite. GOES-A launched on a Delta rocket from Cape Canaveral, Florida. GOES satellites all have a geostationary orbit, which means they always face the same part of Earth — in this case, the Indian Ocean. Once GOES-A became operational, it was renamed GOES-1.

The GOES satellite fleet has grown over the years, and is a critical link in the chain of satellites tracking Earth's weather from space. In 2016, NASA and NOAA launched GOES-R, the first in a new next-generation series of GOES weather satellites, with more to follow in ensuing years.

Why it mattered

With weather forecasts so prevalent (you can literally find them in the palm of your hand with a smartphone), it may be hard to think that such daily information wasn't always readily available. But that was the case when NOAA began building what has become an essential part of the U.S. weather monitoring fleet of satellites.

GOES-A, or GOES-1 as it was later called, "gave forecasters their first near-real time look at atmospheric conditions from a fixed location," NOAA officials said in an overview.

The satellite launched from Pad 17A at what is now the Cape Canaveral Space Force Station and returned its first photo just nine days after liftoff, on Oct. 25, 1975. The satellite was equipped with a Visible/Infrared Spin Scan Radiometer (VISSR) to capture Earth observations in daylight and nighttime to track clouds and surface temperature.

The spin-stabilized satellite was able to observe Earth just 10% of the time, but was still the most up-to-date satellite observations for weather forecasters.

GOES-1 was active until March 7, 1985, when it was ultimately decommissioned. But during that time, NASA and NOAA launched five more successors, GOES 2, 3, 4, 5 and 6.

"For 50 years, GOES data has been the backbone of short-term forecasts and warnings of severe weather and environmental hazards in the Western Hemisphere and forecasts and warnings of space weather hazards," NOAA wrote while celebrating 50 years of GOES satellites. "Each successive generation of GOES has brought improvements and new capabilities to monitor our part of the world."

Since the first next-generation GOES satellite, GOES-R, launched in 2016, NOAA has flown another three satellites, most recently with GOES-U weather satellite launch in 2024.

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