The decades-long search for life elsewhere in the universe is building to a crescendo in 2021.

Driving the news: Three new Mars missions are slated to arrive at the Red Planet in February and a powerful space telescope is expected to finally launch this year.

Details: NASA's Perseverance rover's landing site is thought to be the geological remains of a river delta — and one of the best places on Mars to search for signs of past life.

• The rover is also going to cache interesting looking rocks for return to Earth on a future mission so scientists can analyze them for signatures of life that might include fossilized hints that microbes once lived in those rocks.
• Two Mars missions from China and the United Arab Emirates will also study the Red Planet, focusing on its geology and atmosphere, which would affect our understanding of any past life on Mars.

NASA is also expected to launch its long-delayed James Webb Space Telescope, which could help scientists gather more data on habitable planets around other stars.

• Hunts for intelligent life that creates radio waves, including the well-funded Breakthrough Listen project, are also continuing to methodically search the skies for these possible signs of life.
• China's FAST radio telescope — the largest in the world — plans to allow international scientists to use the powerful tool in 2021.

Between the lines: The search for life today isn't just about finding Earth 2.0 or even microbial life on Mars.

• Scientists are following up on last year's discovery that there may be a gas in Venus' atmosphere that could indicate life in the planet's clouds.
• That finding is helping to widen the scope of the search for life elsewhere, according to astrophysicist Jessie Christiansen.
• "[I]t doesn't need to be a balmy beach on the side of a tropical ocean somewhere where a few strands of proteins come together," Christiansen told Axios.

The big picture: Astronomer Frank Drake famously estimated there are on the order of about 10,000 detectable societies in our galaxy.

• If that's correct, "[y]ou have to look at a few million [star systems] to find one,” astronomer Seth Shostak of the SETI institute told Axios. Now, he says, researchers are getting closer to surveying that many stars.
• So far, the hunt for life beyond Earth has only focused on scanning a relatively small amount of the sky for radio waves from elsewhere and scientists have only recently figured out that most stars have planets around them.

What to watch: LUVOIR and HabEx, two proposed space telescopes NASA is considering building, would characterize and find possibly Earth-like worlds around distant stars.

• "That's the holy grail in terms of looking for life because that's the one place we know that life has happened: on an Earth-like planet around a star like the Sun," Christiansen said.

Yes, but: While all of these missions will set scientists up to figure out more about whether and where life might exist elsewhere in our universe, it's no guarantee they'll actually find it.

• Scientists have found hints of possible life on Mars and potentially habitable planets for years, but knowing whether any hard evidence is actually a sign of life is far more difficult.
• "The real problem is you cannot guarantee that if you spend this amount of money, you will book success," Shostak said of radio wave hunts in particular.
• These missions, however, will focus the search.