Even as the debate heats up on whether we need a "backup" planet, as advocated by tech billionaire and SpaceX CEO Elon Musk, the resolve to take humans to Mars got stronger in 2018.
Musk told the media in November that there is "70 per cent chance that he will go to Mars", despite a "good chance" of him not surviving either on the way or after landing. It is only very likely that only a few people might be willing to join Musk in this journey - either because of the risk or the cost involved.
But his "Starship" (formerly known as the BFR), a fully reusable vehicle designed to take humans and supplies to Mars and also to dramatically cut travel time within Earth, got its first reservation from a private passenger this year -- Japanese billionaire Yusaku Maezawa -- who is scheduled to start a journey to the Moon in 2023.
This year, the US space agency NASA also firmed up its plans to return humans to the Moon and use its lunar experience to prepare to send astronauts to Mars in the 2030s.
In February, NASA hosted a conference for scientists to discuss future exploration and research using the Gateway spacecraft that will orbit the Moon and support human and robotic missions. In the following months, the space agency announced several measures to take the mission forward.
"We created new US commercial partnerships to land back on the Moon. We made breakthroughs in our quest to send humans farther into space than ever before," NASA Administrator Jim Bridenstine said in a statement.
Boosting such ambition this year was a demonstration of a new nuclear reactor power system that could provide surface power on the Moon and Mars.
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What excited the scientists even more was the discovery of a large saltwater lake under the ice near the South Pole on the Red Planet - raising the possibility of life being there on Mars in some form.
The discovery by a team of Italian researchers was made using an instrument on the European Space Agency's Mars Express spacecraft.
While a manned-mission to Mars is still at least a decade away, NASA successfully launched this year a probe to "touch the Sun". The mission broke records for fastest human-made object and closest approach to the Sun, and sent home its first light images - including a picture of Earth - in late October, NASA said, adding that the probe's first flight through the Sun's outer atmosphere was on November 7.
In 2018, NASA's first asteroid sample return mission reached its destination after a two-year journey. The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft arrived at asteroid Bennu on December 3. Analysis of initial data from the mission revealed water locked inside the clay that makes up Bennu.
This year also marked only the second time in history that a human-made object reached the space between the stars as NASA's Voyager 2 probe exited the heliosphere -- the protective bubble of particles and magnetic fields created by the Sun.
The year also bid farewell to two veteran scientific spacecraft - one of them NASA's Kepler space telescope that ran out of fuel after nine years of searching for planets outside our solar system.
NASA, however, now has a probe to take forward Kepler's job. The Transiting Exoplanet Survey Satellite (TESS), launched in April, is continuing the search for planets outside our solar system.
NASA said its Dawn mission, which was launched in 2007, also ran out of fuel this year, but not before becoming the first spacecraft to orbit two separate bodies in the solar system - the asteroid Vesta and dwarf planet Ceres.
The year also brought relief to space enthusiasts as Russian Cosmonaut Alexey Ovchinin and US astronaut Nick Hague escaped unhurt after their Soyuz spacecraft heading to the International Space Station (ISS) had to make an emergency landing due to a booster failure.
And even as the US remains at the forefront of space exploration, the world has learned to train its eyes on China, which is reportedly developing a new-generation manned rocket and spacecraft for its lunar explorations.
(Gokul Bhagabati can be contacted at gokul.b@ians)
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