It's been a busy year in space with new Mars missions launched, a NASA probe saying hello to Jupiter, and humanity's most ambitious comet exploration mission drawing to a close. It was a year when NASA geared up for the return of astronauts to deep space, and new launch vehicles reached technological milestones as well as suffering frustrating setbacks. It was also the year when we said goodbye to the last of the Mercury Seven astronauts. So join us as we look back on the highlights of the year in space, 2016.

Blast off ... and some spectacular landings

In some ways, 2016 felt a bit like the early 1960s as NASA and private companies jockeyed to create the next generation of launch vehicles that can not only deliver payloads into space, but also return to Earth for reuse. Unfortunately, like the 1960s, it was also a year marked by setbacks, delays, and spectacular launch pad explosions.

SpaceX

Elon Musk has never been accused of thinking small and his SpaceX commercial spaceflight company reflected this ambition in 2016. A Falcon 9 rocket chalked up a first on April 9 when, during the CRS-8 mission, it nailed the first-ever powered space booster landing at sea. Proving this was no fluke, on May 5, the company did it again – only at night, at high speed, and with very little fuel.

There was a slight glitch in June when a fourth sea landing attempt ended in a "rapid unscheduled disassembly" or, as it's commonly known, a crash. However, SpaceX bounced back on July 17 when it made another barge landing after sending the CRS-9 mission into space.

Things were going so well that Musk was cheerfully talking about attempting an unmanned Mars landing in 2018, which is a full four years ahead of schedule, followed by a manned landing in 2025. He then followed this up by outlining an audacious plan to send anyone who fancies it to Mars for US$100,000 on a"Battlestar Galactica" cruiser.

Unfortunately, such optimism was dampened by a launchpad explosion of a Falcon 2 on September 1 in an accident of a type not seen on US soil in over 60 years. The blame eventually fell on a problem with the helium system used to pressurize the propellant tanks, but the ongoing investigation has resulted in the next Falcon 9 flight being delayed until January 2017 and the first manned flight of the Crew Dragon until 2018.

Blue Origin

Meanwhile, Blue Origin continued its New Shepard program to develop its own reusable booster. On April 2, the New Shepard rocket made its third powered landing. After a live-broadcast flight and landing in June, the company followed up with an escape system test on October 5 when an unmanned capsule was blasted away from the booster in an emergency simulation. The company expected the New Shepard rocket to be destroyed by the maneuver, but it miraculously survived and landed safely.

Blue Origin also announced that it's already looking ahead to its next generation of launchers by unveiling plans for its New Glenn booster. Like the New Shepard, it's designed to be a reusable powered lander, but differs in that its larger variant – it will only be 50 ft (15 m) shorter than the veteran Saturn V rocket of the Apollo era.

Orbital OTK

It was also a comeback year for Orbital OTK. Almost two years after a disastrous liftoff explosion, Orbital-ATK's Antares booster went back into service in October, lifting off from NASA's Wallops Island facility in Virginia carrying the commercial OA-5 mission to deliver an Enhanced Cygnus unmanned cargo ship to the International Space Station.

Virgin Galactic

In the suborbital market, Virgin Galactic returned to the skies over a year after a fatal test flight accident of Spaceship (VSS) Enterprise. On December 4, Virgin Galactic's VSS Unity made its first free glider flight after being dropped by the WhiteKnightTwo mothership over the Mojave Desert during one hour 20 minute flight that included a ten minute, unpowered free flight to test the craft's systems and collect telemetry data.

NASA

Despite all the private commercial activity, NASA wasn't sitting idle. Work continued through the year on the Orion space capsule, with Crash test dummies abused in the name of safety, new solar panels readied for the next unmanned flight, and recovery operations practiced by the US Navy. The space agency even went so far as to see if food bars have the "right stuff" to provide breakfast for the crew of hungry astronauts.

Living and working in space

In addition to its usual scientific work, the International Space Station saw many firsts in 2016, and even got a little bigger in 2016.

Space Marathon and endurance records

On April 25, British astronaut Tim Peake set one of the oddest imaginable sport records by completing the London Marathon while aboard the ISS. Finishing in 3 hours 18 minutes, and 50 seconds. Peake used a treadmill in the Tranquility module, so he didn't spend three hours rushing about the space station yelling "gangway!" One of the most surprising aspects of the feat is that he is the second astronaut to run a marathon in space.

On August 24, Expedition Mission Commander Jeff Williams completed a marathon of a different kind by becoming the most experienced NASA astronaut to date. On his fourth space mission, the former US Army Colonel racked up 521 days cumulative days in orbit – beating former astronaut Scott Kelly's record of 520 days. When Expedition 48 came to an end and Williams returned to Earth on September 6, that total will be an impressive 534 days.

Inflatable habitat

In April, the CRS-8 mission docked with the ISS with a cargo that included the first inflatable space habitat. The 1,400-kg (3,086-lb) experimental Bigelow Expandable Activity Module (BEAM) is an inflatable storage module made of air-tight fabric based on NASA's abandoned TransHab. It's designed to provide living and working areas for astronauts, while reducing launch costs.

The BEAM was attached to one of the docking ports on the Tranquility module and inflated using a built-in pressurization system on May 28. It will remain on the station for two years while the crews assess its structural stability, leak rate, and ability to withstand radiation and temperature variations. At the end of the test period, the module will be jettisoned from the ISS and burn up on re-entry.

Planetary missions

2016 was an especially busy one in the field of planetary exploration. New missions were launched, old ones began to wind down, some ended abruptly, and some gracefully. In addition, old mysteries were solved and new ones cropped up to bewilder scientists.

Mars

Mars got a little crowded in 2016 with expeditions from the United States, Europe, Russia, and India on station, and more on the way from China and even private companies. Some have been remarkably successful and at least one new arrival ended with an unintentional bang.

Exomars

The ambitious Russo-European Mars technology demonstrator mission took off on March 14 from the Baikonur cosmodrome in Kazakhstan. A joint venture by ESA and Roscosmos, Exomars 2016 is the first of a two-phase mission to evaluate technologies for use on later expeditions to explore the Red Planet with the second unmanned probe scheduled to launch in 2020.

ExoMars 2016 arrived at Mars on October 19, but it was a bit of a mixed bag. While the Trace Gas Orbiter (TGO) mothership successfully went into orbit around the planet, the Schiaparelli lander was less lucky. Instead of making a soft landing on the Martian surface, a sensor error overloaded the computer and caused the probe to think it had already landed when it was actually thousands of feet in the air. The result was that it jettisoned its parachute early and fired its descent engines for only a couple of seconds, crashing into the Red Planet where one of its fuel tanks exploded.

Curiosity

On the space veteran's front, Curiosity started year five of what was initially planned as a two-year mission to explore the Red Planet. The US$2.5 billion unmanned nuclear rover is still seeking out areas where life once could or could now exist. However, it is showing signs of age as its computers continue to give trouble, its sampling drill tends to seize up, and its high-tech aluminum wheels threaten to disintegrate under the pummeling from the rough Martian terrain.

Beagle 2

2016 also saw Mars give up one its mysteries. In November as scientists at the University of Leicester and De Montfort University uncovered evidence that the UK's Beagle 2 lander actually succeeded in landing on Mars in 2003.

High resolution images from NASA's Mars Reconnaissance Orbiter (MRO) indicate that instead of crashing or getting tangled in its landing system, Beagle 2 made it down safely to the Martian surface and even activated itself. However, a badly deployed solar panel prevented the lander's antenna from pointing properly, so it was never able to send a signal home.

Jupiter

Juno

Mighty Jupiter received a new visitor from Earth on July 4 as NASA's Juno probe went into orbit around the giant planet to start a 20-month science mission. After a 35-minute entry burn, the spacecraft went into a highly eccentric polar orbit that will allow it to come within a record 2,500 mi (4,200 km) of the Jovian north pole. This allows the unique solar-powered orbiter to not only take some of the highest resolution images ever of Jupiter, but to skirt within the planet's deadly radiation belts.

Saturn

Cassini

While Jupiter said hello to a new Earth probe, Saturn is saying goodbye to an old one. In January, NASA's Cassini spacecraft carried out a series of engine burns that were the beginning of the end for the 20-year mission. Cassini spent 2016 exploring the poles of Saturn, returning images of an enormous hexagonal north polar jet stream. It also flew in a skimming trajectory over the planet's famous rings in 20 flybys and sent back highly detailed radar images of the sand dunes on Saturn's giant moon, Titan.

Cassini is scheduled to be destroyed in September next year during a controlled plunge into Saturn's atmosphere designed to avoid possible bio-contamination of the Saturnian moons.

Pluto

New Horizons

Even though the New Horizons deep-space probe flew by Pluto in July 2015, it continues to surprise scientists, having recently completed a 16-month dump of data collected during those dramatic few hours. The unmanned spacecraft is currently on a rendezvous with a Kuiper object called 2014 MU69, which is about a billion miles beyond Pluto, but as it travels it's still sending back observations on the solar winds on the outer frontiers of the Solar System.

The data sent back by New Horizons will keep scientists busy for many years to come. Already it has provided new insights into the nature of the planet's largest moon, Charon, and has indicated that there may be a slushy subsurface ocean beneath Pluto's Tombaugh Regio, as well as evidence that the dwarf planet experiences cloudy weather.

Comet 67P/Churyumov-Gerasimenko

Rosetta

2016 saw ESA's Rosetta land on its final resting place on comet 67P/Churyumov-Gerasimenko, wrapping up one of the most ambitious missions ever sent to explore a comet as. After 12 years of voyaging, the deep-space probe made a controlled landing on September 30 to impact on the comet's surface and shut down all its systems for the last time.

Philae

Meanwhile, on July 26, ESA said farewell to Rosetta's Philae lander. In November 2014, Philae became the first spacecraft to make a soft landing on a comet, but instead of securing itself as planned, the unmanned probe bounced several times in the extremely low gravity before coming to rest on its side in a crevice, where it was unable to recharge its batteries using its solar panels.

Though contact was reestablished occasionally as the comet swung close to the Sun, it never amounted to more than brief signals and as 67P headed back to the outer Solar system, mission control called it a day and stopped its listening brief. However, in September there was a happy postscript as images from Rosetta allowed the space agency to confirm the previously unknown spot where Philae now rests.

Looking outward

James Webb

Back on Earth, two new telescopes were limbering up to take on the heavens this year. NASA's James Webb Space Telescope (JWST) completed assembly in April at the Goddard Space Flight Center and in November testing of a key component was completed in anticipation of the Hubble Space Telescope's replacement's launch in 2018.

FAST

Meanwhile, half a world away in Guizhou Province, China, work was completed on the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The massive 1.5 billion yuan (US$180 million) telescope began operations in September, taking the title of the world's most powerful single-dish radio telescope from Arecibo in Puerto Rico.

In memoriam

John Glenn

Finally, 2016 rounded out on a somber note with the passing of one of the legends of the Space Race and former US senator Colonel John Glenn on December 8. The decorated fighter pilot of World War II and the Korean War was the last surviving Mercury Seven astronaut. He became an American hero after becoming the country's first man to orbit the Earth on February 20, 1962 aboard the Mercury-Atlas Friendship Seven space capsule. He later went on to serve in the United States Senate for 25 years and became the world's oldest astronaut in 1998, when he returned to space as a passenger/specialist on STS-95 Discovery.

Stay tuned to New Atlas in 2017 for news of all the latest advances in space exploration and aerospace technology.

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