50 years ago the space race took humans to the moon

In 1969, Neil Armstrong became the first human to walk on the moon. Those first steps were preceded by a fast-paced technological race between the Soviet Union and the USA. Here's how it all started.

The story of human spaceflight begins in the 1950s. It was a time when there were just two superpowers: the USA and the Soviet Union. And they gave the world a bitter arms race.

If you dominated in space, you could also dominate on Earth. That was the thinking. And the Soviet Union was out in front. After all, there's little difference between a space rocket and an inter-continental ballistic missile.

John Glenn was one of the first American astronauts. Glenn was a fighter pilot during the second world war and in the Korean War. As a test pilot in 1957, he flew the first supersonic aircraft for the US air force. But he wasn't so sure whether the US would win the space race against the Soviets. "They had been launching rockets and ours had been blowing up too much on the launchpad," recalled Glenn later. "That was the background to what happened in 1957, when they sent up Sputnik."

  The Americans were slower but more thorough


  Sputnik was the first ever satellite

As was discovered later, Sputnik wasn't a particularly elaborate piece of technology — it was a metal ball with a simple radio transmitter and receiver inside.

But the Soviet success shocked the world. And put pressure on the US government to counter this new threat from space.

"In 1957, Sputnik signaled the beginning of the space age, and the United States was behind," said US astronaut Neil Armstrong.

The USA's answer to Sputnik was a far more complex satellite called "Explorer 1."

But not only that, the then-president, Dwight D. Eisenhower, also established an American space agency, NASA.

A clear vision: Human spaceflight

America's goal was to send humans into space.

"We have one of the most challenging assignments that has ever been given to modern man," said Eisenhowever in a speech at the time.

"We will be developing and launching into space vehicles needed to obtain scientific data and to explore the solar system. We will be preparing for the day when manned flight goes into space," he said.

And the American engineers were sure they could do it, too. They had Wernher von Braun on their side.

Wernher von Braun was a aerospace engineer, who had built rockets for Nazi Germany. After the war, von Braun migrated to the US with about a hundred of his best experts and built an American missile program.

The American public saw von Braun as the ultimate expert. It was only later, in the 1970s, that people started to ask questions about von Braun's Nazi past and his involvement in war crimes.

But that wasn't an issue for von Braun in the 1950s.

His sole concern, and that of his team, was delivering better satellites than the Soviets. And they succeeded.

"We have produced more scientific knowledge with our smaller vehicles than the Russians have with their much larger ones," boasted von Braun during a press conference.

Skeptical test pilots

American test pilots at the time were less than enthusiastic about sending humans into space.

"They were trying to convince me how neat it would be to get into a capsule on top of a rocket," recalled US astronaut, Walter Schirra, later. "And I said: No way! Send the idiot who is sitting on a canon in the circus — and forget us! Then they tried to convince me: 'No, it will be alright — we'll put some monkeys and chimpanzees in first'. But I thought: Now I know I want out of here! So I really had a very negative opinion of it."

Schirra's objections did not hold long.

In 1959, Schirra become one of the first seven astronauts presented by NASA to the public for its Mercury Project.

They were full of optimism in front of the press.

And then the first Mercury rocket started, with a major fault.

"None of us has ever seen a missile launch," said Glenn, who was one of the original seven. "The booster launches and we see a big flame and we stand there watching it like this. And here these seven budding astronauts watching this go up to 27,000 feet and it blew. And it just looked like an atomic bomb over our heads. Then we were looked at each other and thought: We'll have to talk to the engineers tomorrow."

Chimpanzees or people

There was another shock sooner after that.

On April 12, 1961, cosmonaut Yuri Gagarin became the first person to orbit the Earth. And the Soviets were out in front again.

"We started launching monkeys and chimpanzees and then they launched Juri Gagarin," recalled Schirra later. "We were totally shocked by that."

It was time for another strong political signal.

John F. Kennedy had been elected US President. And like Eisenhower before him, Kennedy was determined to take the technological lead from the Soviets.

In a speech, Kennedy said: "I believe that this nation should commit itself to achieving a goal, before this decade is out, of landing a man on the moon and returning him safely to the Earth."

Then, in another speech, he reiterated his determination: "We choose to go to the moon in this decade and do the other thing, not because they are easy, but because they are hard."

The Soviet lead shrinks

Kennedy could say that because the US had started to catch up.

When Alan Shepherd became the first American to orbit Earth on May 5, 1961, the gap between them and the Soviets had shrunk to less than a month.

The USA had switched to the fast lane.

In the next eight years, the USA launched almost twice as many space missions as the Soviets. However, America's good run was not all good. In 1967 a spacecraft exploded during a ground test and three astronauts died.

That threw the American space program back by 21 months.

But it didn't stop NASA from setting ever more ambitious goals — such as the first moon orbits in October and November 1968. It was the first time astronauts had seen the far side of the moon.

"On Apollo 8, we rotated the spacecraft and saw for the very first time the far site of the moon, only 60 miles below," said US astronaut James Lovell later. "And we were like three school kids looking into a candy store window. I kind of forgot the flight plan for a second as those ancient old craters slowly slipped by."

Media-friendly frenzy

It was a short step from there to landing on the moon.

Apollo 11 was the first mission to land on lunar surface.

Astronaut Michael Collins stayed back in the orbiter when Buzz Aldrin and Neil Armstrong undocked from the Command Module in the landing vehicle, the Eagle.

"There are certain events in life, that you never forget and the lunar landing, and in particular, the last seconds leading up to the landing will never be forgotten," said Gene Kranz.

Kranz was the Flight Director at NASA's control center in Houston, Texas. While trying to land the capsule on the moon's surface, various computer alarms went off.

"As the crew took over, about two minutes prior to landing, searching for the landing site, we knew that we were using a lot more fuel than we had expected," recalled Kranz.

Things remained hectic, even after the successful landing and Armstrong and Aldrin had said those legendary words: "the Eagle has landed."

"No controller had a chance to absorb the emotion of that landing," Kranz recalled, "because we had to work for the next two hours — nonstop."

The moon landing was a world first. And so was the live coverage of the event on TV.

Public interest was huge. More than 2000 journalists were accredited at Cape Canaveral and Houston.

"Up until that moment, TV had always been a goal, but not a requirement," said Kranz.

And that everything would work in the deciding moment was far from certain.

"Once, we landed safely, the only thing that counted for us was to see the picture. What I felt at that moment was: 'The TV better work or else!' and if it doesn't they really will know who I am — because I will be the man who didn't bring you television on the moon."

But the technology delivered and millions of people across the world watched as Neil Armstrong became the first human to put a foot on the moon, and said those other legendary words:

"That's one small step for [a] man, one giant leap for mankind."

Moon station 'Deep Space Gateway' to be built by Russia and US

Work on a joint US-Russia space station orbiting the Moon is to begin in the mid 2020s. The base is intended to serve as a launching point for manned missions to Mars.

The US and Russia on Wednesday announced plans to cooperatively build the first lunar space station.

Roscosmos and NASA — Russia and America's space agencies — said they had signed a cooperation agreement at an astronautical congress in Adelaide.

The agreement brings Russia onboard to the Deep Space Gateway project announced by NASA earlier this year, which aims to send humans to Mars via a lunar station.

The proposed station would serve as a base for lunar exploration for humans and robots, and as a stopover for spacecraft.

"While the Deep Space Gateway is still in concept formulation, NASA is pleased to see growing international interest in moving into cislunar space (between Earth and the Moon) as the next step for advancing human space exploration," said Robert Lightfoot, acting administrator at NASA headquarters in Washington.

The two nations would work together to develop the systems and standards needed to organize scientific missions in lunar orbit and to the surface of the Moon, Roscosmos said.

The partners intend "to develop international technical standards which will be used later, in particular to create a space station in lunar orbit," Roscosmos said.

Participants agreed it was important to develop unified standards to avoid future problems in space, Igor Komarov, Roscosmos's general director, said in televised remarks.

Roscosmos and NASA have already agreed on standards for a docking unit of the future station," the Russian space agency said.

"Taking into account the country's extensive experience in developing docking units, the station's future elements — as well as standards for life-support systems — will be created using Russian designs."

The two agencies plan to begin main works in the mid 2020s and will model the station on the ISS.

Why aren’t Jeff Bezos and Elon Musk trying to colonize the moon?

In terms of distance, the moon is easier and less expensive for humans to access. So why aren’t we racing to colonize the moon? How come Elon Musk is so obsessed with Mars?

The space race between Russia and the United States is over, but that doesn't mean interest in the moon has dried up – now, along with national governments, multi-billion dollar companies are making moon (and Mars, by association) landing a priority.

This generation's race, in proper form, is taking place between former PayPal CEO, amateur rapper and Tesla tycoon Elon Musk and Amazon's owner Jeff Bezos, who also owns the Washington Post.

The logic appears to be: Once the European regulators get too tough, you've gotta set up shop somewhere else.

Musk and Bezos both plan to visit the moon before NASA's Artemis mission plans to land in 2024, picking up where the 12 moonwalkers of the Apollo missions left off. However, the main goal isn't the moon, but Mars.

Musk says he's going to space because "there's nothing more exciting than being out there among the stars”, while Bezos' ambitions are fueled by a belief that "we will run out of energy” on Earth.

Musk published an ambitious self-authored study last year outlining his vision of Mars colonization. The report acknowledges the importance of visiting the moon first as a sort of stopping-off point, a choice Bezos and NASA have also deemed prudent.

Both Bezos and Musk have pledged to assist in NASA's recently announced 2024 mission to the moon, Artemis. The mission, previously scheduled to send humans to the moon by 2028, was hastened to 2024 in March by an

order issued by the Trump administration.

If everyone cares about Mars more, why are we going back to the moon? 

Neil Armstrong and Buzz Aldrin's initial Apollo 11 moon landing was more of a political triumph over the Soviet Union than a scientific one – the mission lasted just 3 days, and little actual scientific work was performed.

However, in the following Apollo missions, astronauts collected rocks allowing scientists to better understand the composition of the moon's surface, many of which they preserved for later generations with better technology to study.

With new remote sensing technology, scientists recently discovered the existence of water on the north and south poles of the moon. This discovery, paired with the knowledge acquired from the preserved moon rock, will better guide Artemis venturers on a quest to discover lunar water.

The existence of this water could be fairly groundbreaking if, with further exploration, more is discovered and scientists are able to find ways to extract it. An ample supply of lunar water could help support a space station on the moon - which was previously considered unlikely due to a general understanding that the moon was drier than the Sahara.

At this point, if anyone wants to colonize Mars, they will need to take laborious, energy-heavy trips from Earth lasting up to 8 months one-way. A moon station could help mitigate the lengthy journey, according to planetary geologist Georgiana Kramer. This could save Mars-faring rockets time, energy and money.

Can we use lunar water?

Because the moon isn't tilted on an axis, like Earth, the poles receive no sunlight at all. Water ice exists in deep craters on these poles, where Artemis plans to land.

NASA planetary geologist Sarah Noble said the source of the water is still unknown, but that it could be the result of comet and meteorite deposition (because the moon has no atmosphere to ward them off); solar winds from the sun, which could bring hydrogen that mixes with oxygen-hosting minerals on the moon's surface; or early lunar volcanism, which could have released water that is still trapped.

Early lunar volcanism also created lava tubes, which are also found on Earth in volcanic areas in Hawaii and Colorado. They are long, cave-like tunnels on the surface of the moon, where lava once flowed and has now cooled

When the feasibility of life on the moon is discussed in online forums such as Reddit, the idea of placing a space station inside one of the lava tubes is often raised. Both Kramer and Noble confirm this could potentially work, depending on what's discovered during the Artemis mission. The rock, Kramer said, could shield the sun's radiation and feature relatively normalized temperatures

Noble said in the short term, life in the tubes isn't part of NASA's plan, but in the long term, they could be investigated by robots.

It will be impossible to know whether these theories are accurate until scientists are able to sample the water, however, which is why Artemis plans to land on the south pole of the moon, where much of it is concentrated. Up to this point, scientists haven't had any physical interactions with lunar water, Kramer said.

If a good amount of water is discovered, it could be used for rocket fuel and drinking, which could make Mars exploration easier.

Which place is better for life: Mars or the moon?

All of that said, Mars simply has more resources than the moon, Robert Zubrin, an aerospace engineer, wrote in a treatise published by the National Space Society's magazine "Ad Astra".

"In contrast to the Moon, Mars is rich in carbon, nitrogen, hydrogen and oxygen, all in biologically readily accessible forms such as carbon dioxide gas, nitrogen gas, and water ice and permafrost. Carbon, nitrogen, and hydrogen are only present on the Moon in parts per million quantities, much like gold in seawater," he wrote.

Zubrin is the author of Mars Direct, a research paper-turned-book advocating for Mars exploration, and heads the Mars Society, which also advocates for Mars exploration.

The moon does not receive enough natural sunlight to grow plants of any variety, Zubrin writes, but Mars does, which will allow future colonists to sustain themselves in a way they never could on the moon.

This is all in addition to the moon's lack of an atmosphere, extreme weather changes and barren, radioactive surface.

Zubrin's analysis of Mars illustrates why life on the moon is only considered in the context of the lunar body serving as a stopping-off point on the way to something bigger and better - or, at least, more sustainable for human populations.

Why isn't Germany taking over the moon?

By and large, "Made in Germany" is not the driving force behind companies in Europe's powerhouse preparing to go to space. The country spends millions on the industry but not nearly enough, say critics.

At a recent gathering in Berlin of space technology businesses the mood was upbeat. Yet while astronaut Matthias Maurer was stealing the show and beguiling schoolchildren and adults alike, there were important issues floating through the air. The biggest question wasn't about colonizing Mars, sending millionaire tourists to the moon or even mining it for minerals. The biggest question of all was: Why isn't tech wonderland Germany at the head of the space race?

Besides giants Airbus and OHB in Bremen, there are a lot of smaller companies and startups looking toward the stars throughout Germany. Standing above all these private companies is the European Space Agency (ESA), an organization made up of 22 member countries with a total budget of €5.72 billion ($6.39 billion) for 2019.

After France, the German government is its second-biggest cash contributor. For this money, Berlin was able to get two prizes: ESA Mission Control in Darmstadt and the astronaut training center in Cologne. This may sound like a big win, but they came at a steep price. Germany's contribution to ESA this year alone was €927 million.

At home Germany spends an additional €285 million on space programs. This may seem like a lot, but it's a pittance compared with France's €726 million. Overall Germany only spends 0.05% of GDP on such programs. This puts them behind India, Italy, Japan, China ,Russia, France and the US which spends 0.224% according to Goldman Sachs' European Space Policy Institute.

Missing the boat

But no matter how much is being spent, many are critical about how it is spent. Right now the lion's share of government cash goes to the major players, Airbus and OHB. Tom Segert, director of business and strategy at the startup Berlin Space Technologies, is one of those who sees change coming though. "We are having a moment where the big players in Germany, but also the smaller players, are waking up. They realize something big is going to happen," he told DW.

In Germany, "we have the technology, but we don't have the demand," said Segert, pointing to the fact that these conglomerates are working on big international projects and building big satellites, not the smaller ones businesses actually want. This is the gap that Berlin Space Technologies wants to fill.

Founded in 2010 by three friends, the startup now has 29 employees who work to design small satellites systems — anywhere from the size of a microwave oven to a washing machine — and the technology behind them.

"Space seemed to be the place where you can always do something new, something that nobody has done before. I didn't know about the bureaucracy that was awaiting me and about all the pitfalls of a government-driven space program," said Segert. Nonetheless, the company has so far taken part in over 50 space missions.

Making a prototype can take 1-2 years. But the company wants to move away from individual satellites into mass manufacturing, and for this they have started a joint venture in India. Once a satellite goes into large-scale mass production, the building time can be reduced to one or two weeks. This drives down costs, and having more satellites in orbit creates a network, a "constellation of satellites" in space.

The forefront of technology


In general, Segert thinks that for most companies building satellites is a waste of resources. They should instead focus on services and data. "The biggest chances for European startups are in the downstream because they are getting the data for free [from NASA or ESA]. It's not the best data, but they get some data for free which is a big hurdle for everybody else."

Focusing more on services will lead to the demise of many manufacturing companies. Only the strongest will survive — Darwin in space — a typical process in maturing industries.

At the same time industry associations are pushing Germany to build a spaceport, or launching center, of its own. They are not talking about those big enough to send humans into space, but one that would enable companies to launch rockets and satellites without depending on other countries. Today only a handful of countries have this capability. Bringing it closer to home would make things easier.

Though such prestige projects fascinate the public, space programs have developed many technologies that have come into normal use and impact daily life. Things like batteries, ceramics, solar technologies, autonomous driving and the use of lightweight metals were all advanced thanks to space innovations.

A shot in the dark

Newer technologies using satellites include better communications, weather forecasting and navigation. Images from space can be used to monitor coral reefs, forests, water levels, fires or natural disasters. They can also watch pipelines, trains and power lines. These images can teach about the Earth and bring home the ideas of global warming.

To make the most of the possibilities in space, Segert from Berlin Space Technologies would like to see industry do more of the things that ESA, Airbus or OHB do — things that are often funded by taxpayers. He also warns companies to stick to the things they are good at like making equipment, components, satellites, rockets, organizing launches or providing services. Not everything at once.

"I am very doubtful about hardware startups that are founded right now because they are very late to the game," concluded Segert. For him the future of the space business in Germany is unclear, it can go two ways: The first would be a business-as-usual model in which the government spends ever-increasing amounts of money to keep national champions alive that skew the marking and where no real progress is made.

In the second model the government, taxpayers and companies would see that things have not been done in the most efficient way. The government will get out of the business of making satellites and turn into a consumer of services. This would lead to a decline in satellite manufactures and costs. Then the focus would be on data, the gold of the 21st century.

Space offers nearly infinite possibilities and a lot of room to grow. Now 50 years after the first moon landing, the real test will be to see if governments will create the legal framework to govern space and then step aside and let the market take over and give consumers what they want. Germany as a big spender can nudge it either way

Astronauts walk on 'Mars' as stress test reaches halfway point

A team of astronauts who boarded a simulated spacecraft in June, 2010, have finally reached 'virtual Mars.' One goal of the experiment is to study the effects of isolation over the 520-day return trip to the red planet.

It may have gone largely unnoticed by the outside world, but a three-man astronaut crew just made history by landing on "Mars" on Monday.

True, it was only an ersatz planet located on Russian soil. But the landing was a significant milestone in an ongoing experiment meant to show whether sending humans to the red planet in reality is at all feasible in future.

The virtual martian landscape the astronauts explored was created in a hall at the Institute of Biomedical Problems (IMBP) in Moscow. Still, Italian crew member Diego Urbina was clearly aware that, virtual planet or not, he also was writing history.

"Today, as I see this red planet surface, I can already feel how inspiring it will be to look through the eyes of the first human to step on Mars. I salute the explorers of tomorrow and wish them Godspeed," Urbina said.

Feet on the ground

Urbina and his Russian colleague Aleksandr Smoleyevsky spent one hour and 12 minutes on the faux-martian surface before returning to their landing vehicle to rejoin Wang Yue from China.

In the coming week, two more sorties will follow, after which the astronauts will start their virtual ascent back to their orbital mothership, where they have been living with three other crew members since June last year.

The six volunteers, including two Europeans, three Russians and one Chinese, are taking part in the first experiment to simulate a manned mission to Mars in real time over 520 days. That is the time necessary to fly to Mars, spend several days on the surface and return to Earth. One of the aims is to see how humans will react, physically and psychologically, to such an undertaking.

The results so far have been encouraging.

They feel OK," IMBP deputy director, Boris Morukov, said. "Once every two months they undergo a thorough medical check-up, their physical condition is being tested all the time, and there is ongoing psychological monitoring. Many have even improved their physical abilities.

Self-reliance

The crew, he said, are still highly motivated, even if some inevitable signs of fatigue are beginning to show. The men have been living together for months in a rather large but still limited space. They have also been subjected to various emergency situations, like the disruption of their main energy supplies. But according to Morukov, the crew coped very well with these calamities.

"What is so typical of a flight to Mars is that it is fully self-supporting," he said. "Spacecraft in orbit are controlled from the Earth, but here the crew has to take decisions independently, on all problems and emergencies."

It would also be impossible for the crew of a Mars voyage to simply turn the ship around and head home if they needed help, Morukov said.

"It is impossible to return to the earth in case of an emergency," he said. "This is a psychological factor which is difficult to simulate, it is difficult to make them believe that they are surrounded by space, and not in Moscow.''

But so far, the simulation appears to have been highly convincing. The first walk on the virtual martian surface was monitored from Russia's very real mission control center outside Moscow. Even the communication with the crew had sounded as if the signal, indeed, had to bridge the whole distance from the Earth to Mars and back.

The crew will spend most of this year on board their spacecraft. Their long, simulated journey back to Earth begins on March 1. The virtual landing on Earth is scheduled for early November. A real manned mission to Mars, if it ever takes place, is unlikely to happen before 2030.

ESA hopes to launch robotic mini-shuttle by 2020

European space authorities are in the very early planning stages of the next generation of unmanned spacecraft. The new mini-shuttle, about the size of a car, would follow an already approved craft, the IXV.

The European Space Agency could launch a new unmanned, robotic miniature space shuttle by 2020, presuming that upcoming planning meetings, which begin this month, approve the project.

The new, as-yet-unnamed shuttle, would be the next version of ESA's Intermediate Experimental Vehicle (IXV), which is slated to enter space in 2013, according to Giorgio Turmino, the IXV's project manager. "The objectives might be robotic servicing of space infrastructures with a re-flyable system of limited sizes (to limit cost on both the launcher and the spacecraft sides)," Tumino said in an e-mail to Deutsche Welle.

This new craft would likely be the European answer to an American space drone, known as the X-37B Orbital Test Vehicle, which has flown two space missions since last year.

Budget of 'millions, not billions'

However, Turmino added that it was still too soon to share many details of the new project, including how much it will cost the 18 member-state ESA.

"The idea is to have a prototype representative of an operational system, built and flown after the IXV," he noted. "The budget should be affordable for ESA member states, based on millions not billions."

By comparison, ESA said in an internal newsletter article published in 2006 that the budget for the IXV project was 55 million euros ($80 million), although the BBC reported in 2009 that the IXV's budget was 130 million euros.

The American space shuttle program is schedule to fly its final mission in early July 2011, which will tie all future re-entry spacecraft - which ferry personnel and equipment to the International Space Station - to the Russian space program until 2013. The IXV, and its planned descendant, would launch from the Guiana Space Center, in Kourou, French Guiana, in South America. Both craft will be designed to survey the Earth from space, as well as potentially repair satellites while in orbit. "The IXV project objectives are the design, development, manufacturing, and on-ground and in-flight verification of an autonomous European lifting and aerodynamically controlled re-entry system," ESA said on the official IXV web page.  

Saturn receiving water from one of its moons, ESA spacecraft finds

The planet's upper atmosphere is marked by the presence of water. But where it comes from has been a mystery until now. The ESA's Herschel spacecraft has identified water shooting from jets on Saturn's Enceladus moon.

The European Space Agency's (ESA) Herschel spacecraft has identified the source of a water vapor ring surrounding Saturn. One of Saturn's moons - Enceladus - spews 250 kilograms (550 pounds) of water vapor into space every second. The announcement was published Tuesday on the ESA's website

Anywhere from three to five percent of that water ends up falling onto the planet itself, influencing the chemical composition of its atmosphere. No other moon in the solar system is known to do so. The water expelled from Enceladus mostly erupts from jets in an area of the moon's south pole known as the "Tiger Strips" for their distinctive markings.

  Paul Hartogh, of the Lower Saxony-based Max Planck Institute for Solar System Research, led the analysis of data gathered by Herschel and told Deutsche Welle the water emitted by Enceladus is "enough to explain the amount of water first discovered in Saturn's atmosphere" in 1997.

The reason why so much water is produced is not clear," he said. "Of course you have this warm area in the south - and that is probably created by some tidal forces - but the exact mechanism is not know. The amount of energy dissipating due to tidal forces is actually not enough to explain why so much water is produced there.

Water for life

According to Tilman Spohn, of the German Aerospace Center's Institute of Planetary Research in Berlin, the discovery is a puzzling one which gives rise to more questions than it answers. Enceladus' eruptions are surprising for a body of its size, he said. A general assumption is that the larger a body in space is, the more unstable and active it becomes.

  This thing is (actually) too small to generate volcanic activity and generate heat," Spohn told Deutsche Welle. "There is much more heat output than you would expect for a body like that."

Yet beyond Enceladus' inexplicable qualities, the moon has caught scientists' interest in part because the presence of liquid water is a prerequisite for life as we know it.

"There is speculation about Enceladus being habitable for microbial life forms - nobody has discovered anything like that yet, but it is a body of particular interest in terms of life outside the earth," Spohn said.

Compared with Earth

Walter Schmidt, a specialist on planets and comets at the Finnish Meteorological Institute of Helsinki, says Enceladus seems to be covered by an ice cap with water underneath.

An early explanation for the eruption of water could be Saturn's gravitational pull on its moon, he said. Other moons of Saturn also have eruptions, although they spew materials other than water into space.

Because of the low pressure in space, the water coming from Enceladus becomes a vapor can't remain in its liquid form or freeze, which is why it becomes vapor, according to Schmidt. The water vapor is then broken down into hydrogen and oxygen by UV light and collisions with solar wind particles. That "basically ensures that water molecules are not stable in space," he added.

Schmidt says studying the conditions on Saturn and Enceladus can help scientists to "understand what makes Earth so special" in its ability to sustain life and explain "how water came here to Earth in the first place."

The spectroscopic capabilities of Herschel allow the spacecraft to distinguish between water, oxygen and hydrogen, Schmidt added.

"Water has a very characteristic spectral distribution and can be detected rather easily," he said. "Once it disassociates these spectral properties are gone, one has to look separately for oxygen lines and hydrogen lines."

ESA spacecraft finds first oxygen gas molecules in space

Scientists have detected oxygen molecules in the star-forming region of Orion. Researchers believe frozen dust particles consisting of oxygen atoms evaporated in the heat of budding stars to form molecules.

In a new scientific paper published on Monday, the European Space Agency's (ESA) Herschel spacecraft has discovered oxygen molecules in space. The findings were published in the August 1 edition of Astrophysical Journal.

While oxygen in its atomic form exists in water and carbon monoxide - and according to researchers is therefore the third most abundant element in the universe - ESA's Herschel mission has discovered the first molecular instance of oxygen space. That is, two oxygen atoms bound together to form the dioxygen (O2) molecule.

 The oxygen molecules were discovered in the Orion star-forming region. However, they are few in number. The scientists used three infrared frequencies emitted by Herschel's far-infrared instrument and found one oxygen molecule for every million hydrogen molecules within gas and dust surrounding Orion's forming stars.

 The scientists had decided to search Orion based on the theory that heat from the constellation's forming stars would evaporate ice from tiny dust grains to form oxygen molecules.

  The largest single mirror ever built for a space telescope is aboard the Herschel spacecraft, which collects "long-wavelength radiation from some of the coldest and most distant objects in the universe," according to the ESA.

Hiding' oxygen According to Göran Pilbratt, a Netherlands-based ESA scientist on the Herschel project, the scientists hope to find out where else in space oxygen molecules may have formed. "

It will certainly be of considerable interest to establish abundances of O2 in different environments to be able to understand what is going on," he told Deutsche Welle in an e-mail. "Obviously non-stationary processes must be at play.

We already now know for a fact a lot of the oxygen must exist in other forms than O2." Pilbratt added that scientists long suspected oxygen molecules exist in space, but have been baffled by their inability to find them. NASA's Submillimeter Wave Astronomy Satellite and Sweden's Odin mission have both searched so far, without any results

Stationary chemical models indicate that a lot of the oxygen in the interstellar medium ought to exist in the form of O2, but previous searches showed this not to be the case, providing upper limits two orders of magnitude lower than the expected abundances," he said

Other space scientists have been encouraged by this result. Bérengère Parise, a French researcher based at the Max Planck Institute in Bonn, whose team last month revealed the presence of hydrogen peroxide in space, said that this new finding is a positive step.

"This discovery will allow astrochemists to refine their models and better understand the chemical interplays between gas and dust particles in interstellar clouds, as well as to understand how much material is frozen out onto the surface of cold dust particles," she wrote in an e-mail sent to Deutsche Welle.

A measured abundance is always much more constraining for models than an upper limit based on non-detections (as was available in the past)," she added. "Star formation theories will also have to take into account the observed abundance of oxygen in the computation of the cooling rates."

NASA's California-based Paul Goldsmith, one of leaders of the international team of investigators, said finding the oxygen molecules opens the door to further questions. "We didn't find large amounts of (oxygen molecules), and still don't understand what is so special about the spots where we find it," he said in a statement. "The Universe still holds many secrets."  

Venus has ozone layer, ESA scientists say

The solar system's second planet's newfound ozone may help to understand other planets. Scientists are hoping for more missions to confirm the presence of simple life on the harsh, turbulent planet.

On Thursday, the European Space Agency (ESA) announced that its Venus Express spacecraft had discovered that Venus, the second-closest planet to the Sun, has an ozone layer.
Scientists say that ozone on a planet may indicate the presence of life.

The ozone found on Venus is at far too small of a concentration to indicate that it derived from life there. But comparisons with ozone levels on Earth could help set parameters to determine the likelihood of life elsewhere

By chance
Scientists from ESA made the determination after analyzing measurements from instruments aboard the Venus Express craft.

"We have been able to identify the signature [of the gas]," Franck Montmessin, an ESA researcher, told Deutsche Welle.

On-board instruments measured changes in wavelength of starlight passing through Venus' rather thick atmosphere.

"It was a bit by chance," Montmessin said. "We carefully looked at the spectra, and we saw some unexpected features," he explained.

The finding built on discovery of ozone on Mars, which "was more obvious," Montmessin added.

Other scientists were excited by these findings.

Anja Bauermeister, an astrobiologist at the German Aerospace Center, who was not part of the new ESA findings, told Deutsche Welle that she thinks the data are trustworthy, in particular since the measurements were taken so close to the planet
As for life - possibly microbial - on Venus, Bauermeister said, "There is speculation."

These tiny, simple forms of life could have occurred shortly after the planet was formed, and if so, then most likely in drops of water in clouds of the upper atmospheric layers.

But the greenhouse effect on Venus, due in part to its lacking a thick ozone layer, has effectively prevented it from being hospitable to life.

"Conditions on Venus are really too harsh - people say it's basically like hell: hot, acidic," Montmessin said.

Ozone on Venus is nowhere near levels indicating that it originated from life. Rather, the Venusian ozone layer is likely a result of sunlight breaking up carbon dioxide in the planet's atmosphere.

Biosignatures

Ozone may, however, act as a "biosignature" - an element indicating the presence of life. "If we find ozone on an exoplanet, we can't just jump for joy and say 'yoo-hoo! We've found life!'," Bauermeister said.

 Exobiologists and astronomers say that the presence of ozone, especially in combination with oxygen and carbon dioxide, is a decent indicator of a higher probability that life may exist on a planet. Bauermeister noted that methane, together with oxygen, is also a good biosignature.

But the best one, she explained, is nitrous oxide, since it's a direct byproduct of life. However, nitrous oxide is extremely difficult to measure in light spectrums, she added

  Further probes

Montmessin said the ozone signatures were found quite high in the atmosphere, at about 100 kilometers from the surface of the planet. The ability for the Venus Express to probe the Venus atmosphere is limited, due to a thick layer of sulphuric acid. "One could send balloons into the Venusian atmosphere" to probe it further,

Montmessin said, adding that this has been done in the past. In any case, he said, "we need to go back to Venus and use other types of measurements to see if there are types of complex organisms there." Author: Sonya Angelica Diehn Editor: Cyrus Farivar  

NASA finds more Earth-sized planets that could support life

The planets are likely the right size and right temperature to support complex life. The Kepler planet-searching telescope has detected nearly 50 such planets in one small part of the observable universe.

NASA said Monday its Kepler Space Telescope mission discovered 10 new rocky, Earth-like planets outside of our solar system which

Are we alone?

 Maybe Kepler today has told us indirectly, although we need confirmation, that we are probably not alone," said Kepler scientist Mario Perez. Those 10 planets were orbiting suns at a similar distance to Earth's orbit around the sun.

This distance is considered the "Goldilocks Zone" - not too close, not too far away from the sun, just right to support life.

 Seven of these planets were circling stars similar to our sun. This does not mean life of any complexity has been found on these planets, but the chances that Earth is the only planet that supports life are dwindling.

  "It implies that Earth-size planets in the habitable zone around sun-like stars are not rare,

" Harvard astronomer Avi Loeb wrote in an email to the AP news agency. Loeb was not part of the Kepler research team. Kepler also discovered 209 other planets, scientists announced Monday.

 More planets than expected The Kepler telescope has detected nearly 50 planets in the Goldilocks Zone in four years of searching. The Kepler telescope only looked at a small part of the Milky Way galaxy.

The telescope studied about 150,000 stars, while the Milky Way contains hundreds of billions of stars.

Before Kepler was launched in 2009, astronomers hoped there would be Earth-like planets around about 1 percent of stars. Scientists involved with the Kepler telescope said that number is closer to 60 percent this weekend. "This number could have been very, very small," said Caltech astronomer Courtney Dressing. "I, for one, am ecstatic."

 The Kepler telescope will soon make way for its successor. The Transisting Exoplanet Survey Satellite (TESS) will observe the brightest 200,000 nearby stars for two years starting next year. The James Webb Space telescope, which will replace the

Hubble telescope next year, will be able to detect the make-up of atmospheres of exoplanets. The James Webb telescope will also be able to determine the possibility of finding potential life forms. kbd/rc (AFP, AP, Reuters)

  

Scientists discover water on planet outside solar system

Astronomers have detected water vapor in the atmosphere of the exoplanet K2-18b. They say it is the first planet beyond earth that has the potential to support life.

Scientists from University College London (UCL) announced Wednesday that they had detected water vapor in the atmosphere of an exoplanet eight times the mass of Earth and 110 light years away. 

The so-called super-Earth, known as K2-18b, is twice the size of Earth and is located in the Leo constellation in the Milky Way.

The scientists reported in the Nature Astronomy journal that K2-18b is in a "Goldilocks," or habitable zone with the right proximity to its sun to make water in liquid form, and thus life, possible.

Looking to answer the big question

Angelos Tsiaras, who was the lead author of the UCL study published in the latest issue of the journal, said: "K2-18b is not 'Earth 2.0' as it is significantly heavier and has a different atmospheric composition. However, it brings us closer to answering the fundamental question:

Is the Earth unique?" Tsiaras and his colleagues made the discovery while using open-source algorithms to analyze data captured by the ESA/NASA Hubble Space Telescope.

 Their analysis of starlight filtered through K2-18b's atmosphere pointed to the unmistakable molecular signature of water vapor. Scientists analyzing the Hubble data say they found hydrogen and helium in K2-18's atmosphere as well.

Heavy gravity and intense radiation

Though the discoveries would suggest the potential for sustaining life, given the planet's extreme gravity and intense UV radiation, it would still be impossible for humans to inhabit it. Still, scientists are excited. Giovanna Tinetti, who co-authored the UCL report, says, "We cannot assume that it has oceans on the surface, but it is a real possibility."

 'The first of many' Another co-author, Ingo Waldmann, says: "It is likely that this is the first of many discoveries of potentially habitable planets.

This is not only because super-Earths like K2-18b are the most common planets in our galaxy, but also because red dwarfs — smaller stars than our sun — are the most common stars."    K2-18b was discovered by NASA's Kepler Space Telescope in 2015. It is one of hundreds of planets with a mass between that of Neptune and the Earth.

 Scientists are confident that many more such planets will be discovered in the near future by NASA's James Webb Space Telescope and the European Space Agency's ARIEL Space Mission, which is set to launch in 2028.

  

New planet discovered in orbit of young Milky Way star

A second planet has been discovered circling Beta Pictoris, 

a fledgling star in our own galaxy offering astronomers a rare glimpse of a planetary system in the making, according to a study published Monday.

We talking about a giant planet about 3,000 times more massive than Earth, situated 2.7 times further from its star than the Earth is from the Sun,"

 said Anne-Marie Lagrange, an astronomer at France's National Centre for Scientific Research and lead author of a study in Nature Astronomy. The new planet, β Pictoris c, completes its orbit roughly every 1,200 days. Like its big sister β Pictoris b, discovered by Lagrange and her team in 2009, it is a gassy giant.

Visible with the naked eye, Beta Pictoris—with a mass nearly twice that of the Sun—is a newborn by comparison: only 23 million years old. 

The Sun is more than 4.5 billion years old. It is also relatively nearby, just over 63 light years, and surrounded by a disk of stellar dust. This swirling halo of debris and gas was the first such configuration to be captured in image, making Beta Pictoris a celebrity star in the 1980s.

 "To better understand the early stage of formation and evolution, this is probably the best planetary system we know of," Lagrange told AFP. Observations show that the two planets are still taking shape.

  β Pictoris c was discovered by analysing 10-years worth of high-resolution data obtained with instruments at the La Silla Observatory in northern Chile,

run by the intergovernmental European Southern Observatory. In 2014, scientists said β Pictoris b spins at a breakneck speed of some 25 kilometres per second (90,000 kph or 56,000 miles per hour).

 Located in the southern constellation of Pictor—"The Painter's Easel"—Beta Pictoris is the second brightest star in its constellation.

UK will lead European exoplanet mission

A telescope to study the atmospheres of planets beyond our Solar System will be launched by the European Space Agency in the late 2020s.

The mission, to be known as Ariel, was selected by the organisation's Science Programme Committee on Tuesday. 

 The venture will be led scientifically from the UK by University College London astrophysicist Giovanna Tinetti. "In the next decade we will see many, many planets being discovered - thousands, actually," she said. "All this is amazing,

but we want to go beyond that and start to understand the nature of those planets, how they formed, how they evolved, and ultimately to put our Solar System in the bigger picture," the principal investigator told BBC News.

  Ariel will use a metre-sized mirror and instrumentation designed to analyse, in visible and infrared light, the chemical make-up of the gases that shroud distant worlds, or exoplanets as they are known.

 This information should provide insights on how certain types of planets come to form around particular stars. Prof Tinetti explained: "We want to sample lots of planets - some that are small like the Earth or very big like Jupiter; and at different temperatures - extremely hot, warm or temperate - around very different types of stars.

We want to sample all the extremes and the more normal cases, because what we want to try to understand is the 'standard model' for planets, if such a model even exists." Ariel (Atmospheric Remote-Sensing Infrared Exoplanet Large-survey)

  Ariel is the latest selection in Esa's Medium Class portfolio. To win the launch opportunity in 2028, the proposal had to beat competition from an X-ray telescope (Xipe) and a mission to study energetic particles around the Earth (Thor).

 A detailed technical assessment will now be conducted before the Ariel project is formally "adopted" - Esa legal-speak for "final go-ahead".

This sign-off, which should happen in the next two years, paves the way for manufacture of the flight hardware. Ariel is the third exoplanet venture chosen by Esa in recent years.

Already coming down the line is a small telescope called Cheops that should go up next year to better measure the size of these far-off worlds; and this will be followed in 2026 by Plato, a telescope that aims to find "true Earths" - planets the same size as our home world that orbit at the same distance from Sun-like stars.

 And the Americans, too, have their dedicated planet-hunters, with the newest, the Transiting Exoplanet Survey Satellite (Tess), launching in the next few weeks. But at some point, the science of exoplanets has to move beyond simply finding and counting objects; their chemical compositions and physical conditions have to be determined.

 The telescope that will start to make big inroads into this problem is the James Webb observatory, the successor to Hubble. Due in orbit next year, it will study planetary atmospheres in exquisite detail with its 6.5m-diameter mirror.

But the US space agency-led mission will probably only get to look at perhaps 150-200 exoplanets in its first five years of operation because of all the other demands on its time from astronomers. Ariel, on the other hand,

will have the single quest and that should see it characterising in the region of 500-1,000 planets during its primary years in orbit.

  Steady platform

And one aspect that would work in Ariel's favour is the absence of any moving parts in its build, commented Plato team-member Dr Don Pollaco from Warwick University, UK.

 "The issue with all of these planet experiments is that the signals you are looking for are so incredibly small that any systematics in the instrument itself will dominate the signal," he explained.

 "And the systematics are often associated with bits that move. So the great thing about Ariel is that it is fixed-format - nothing changes," he told BBC News. Ariel is likely to cost Esa about €460m (£405m) for the spacecraft chassis, the launch vehicle and operations.

As is customary for science missions like this, the agency's individual member states pick up the cost of the scientific payload. The UK will have the technical lead on the project and the instrumentation therefore will be assembled at the Rutherford Appleton Laboratory at Harwell in Oxfordshire.

 Dr Graham Turnock, the chief executive of the UK Space Agency, said: "It is thanks to the world-leading skills of our innovative space community that a UK-led consortium has been chosen to take forward the next ESA science mission.

This demonstrates what a vital role we continue to play in European collaboration on research in space. "The Ariel mission is a prime example of the scientific innovation underpinning the wider economy. It relies on the UK's science and engineering expertise, which are at the forefront of the government's Industrial Strategy."  

James Webb Space Telescope comes together

The successor to the Hubble observatory has reached a key milestone in its construction.

All the elements that make up the James Webb Space Telescope (JWST) have been brought together for the first time. 

 It sets the stage for some critical tests that will hopefully lead to a launch to orbit sometime in 2021. JWST will use a colossal mirror and state-of-the-art instruments to try to see the glow from the very first stars to shine in the Universe. 

 It will also have the power to resolve the atmospheres of many of the new planets now being discovered beyond our Solar System, and to analyse their atmospheres for the potential for life. 

 The telescope is a joint endeavour of the American (Nasa), European (Esa) and Canadian (CSA) space agencies.  

It can be thought of as having three main parts - a telescope (mirrors and instruments); 

a big sunshield to shade its sensitive view of the sky; and a spacecraft unit that will manage the observatory's day-to-day operations in orbit. 

 These three segments have finally been bolted together at a Los Angeles factory facility belonging to the prime contractor, Northrop Grumman.  

All the components that have gone into making JWST have been repeatedly tested - at both the individual and the integrated level. That cycle of testing continues now that the three major segments are connected.

  A vital test will be a demonstration that Webb can fully deploy its sunshield. This tennis court-sized parasol is made up of five extremely thin layers of Kapton insulating film. Its job is to put the mirrors and four instruments completely in the shade when observing the cosmos. 

Stray light from our Sun would otherwise warm surfaces and swamp the faint infrared radiation coming from distant galaxies. But to be effective, the shield must roll out properly without kinks and without tears. 

 "This is an exciting time to now see all Webb's parts finally joined together into a single observatory for the very first time," said Gregory Robinson, the Webb programme director at Nasa HQ in Washington, DC. 

 "The engineering team has accomplished a huge step forward and soon we will be able to see incredible new views of our amazing Universe."

Anyone who has followed the story of JWST knows it is running late - very late, by more than decade. The project has also gone massively over-budget. The cost after build, launch and five years of operations is estimated to be about $10bn. 

But this is a venture that astronomers fully expect to be a revelation. The current Hubble telescope, for example, is restricted in how deeply it can see into space - and therefore how far back in time it can see. 

Its 2.4m-wide mirror cannot quite collect enough photons, and its instruments are not sensitive in just the right portion of the electromagnetic spectrum to be able to probe the era of first star formation - more than 13.5 billion years ago. 

JWST in contrast has a 6.5m-wide mirror - seven times the light-collecting area of Hubble - and its instruments will be perfectly tuned in the infrared to pick up the light from these founding stars.  

Exoplanet discovered around neighbouring star

Astronomers have discovered a planet around one of the closest stars to our Sun.

Nearby planets like this are likely to be prime targets in the search for signatures of life, using the next generation of telescopes. The planet's mass is thought to be 3.2 times that of our own, placing it in a category of world known as a "super-Earth". It orbits Barnard's star, which sits "just" six light-years away. The star is an extremely faint "red dwarf" that's about 3% as bright as the Sun.

  The research is published in the journal Nature. Co-author Guillem Anglada Escudé said the newly discovered world was "possibly a mostly rocky planet with a massive atmosphere. It's probably very rich in volatiles like water, hydrogen, carbon dioxide - things like this. Many of them are frozen on the surface".

The Sun's closest neighbours

Dr Anglada Escudé, from Queen Mary University of London, added: "The closest analogue we may have in the Solar System might be the moon of Saturn called Titan, which also has a very thick atmosphere and is made of hydrocarbons. It has rain and lakes made of methane."

The planet, Barnard's Star b, is about as far away from its star as Mercury is from the Sun. It's the second closest exoplanet to Earth after Proxima Centauri b, whose discovery was announced in 2016.

The planet orbits past a boundary called the "snow line", beyond the traditional habitable zone where water can remain liquid on the surface. On distance alone, it's estimated that temperatures would be about -150C on the planet's surface. However, a massive atmosphere could potentially warm the planet, making conditions more hospitable to life.

  The researchers used the radial velocity method for their detection.

The technique can detect "wobbles" in a star caused by the gravitational pull of an orbiting planet.

 These wobbles also affect the light coming from the star.

As it moves towards Earth its light appears shifted towards the blue part of the spectrum and, as it moves away,

it appears shifted towards the red. Earth-sized planet orbits neighbouring star Where should we look for aliens? Could Nasa's next big thing detect alien life? "This planet is particularly complicated because the orbital period (the time to complete one full orbit of the host star) is 233 days. In one year, you only see one part of the cycle, and you have to cover it over many years to be sure that it's repeating," Dr Anglada Escudé told me.

The team re-examined archived data obtained from two astronomical surveys over a 20-year period. They also added new observations with the Carmenes spectrometer in Almeria, Spain, the Eso/Harps instrument in Chile and the Harps-N instrument in the Canary Islands. It's the first time the radial velocity technique has been used to detect a planet this small so far away from its host star

We couldn't get a single experiment that would detect it unambiguously, so we had to combine all the data very carefully," said the Queen Mary University of London astronomer. "We found a lot of systematic errors from several of the instruments that were producing "ghost signals".

It was not only about getting new data but also about understanding the systematic effects. Only when we had done that did the signal become very clear and obvious."

 When the next generation of telescopes come online, scientists will be able to characterise the planet's properties. This will likely include a search for gases like oxygen and methane in the planet's atmosphere, which might be markers for biology.

 "The James Webb Space Telescope might not help in this case, because it was not designed for what's called high contrast imaging. But in the US, they are also developing WFirst - a small telescope that's also used for cosmology," said Dr Anglada Escudé. "If you take the specs of how it should perform,

it should easily image this planet. When we have the image we can then start to do spectroscopy - looking at different wavelengths, in the optical, in the infrared, looking at whether light is absorbed at different colours, meaning there are different things in the atmosphere." 

This is not the first time there have been claims of a planet around Barnard's Star. In the 1960s, the Dutch astronomer Peter van de Kamp, working in the US, published his evidence for a planetary companion, based on perturbations in the motion of the star. However, van de Kamp's claims proved controversial, as other scientists were not able to reproduce his finding.

 "The new planet is impossible for Peter van de Kamp to have detected. The signal would have been too small for the technique he was using," said Guillem Anglada Escudé. However, the new data contain tentative hints of a second planet orbiting Barnard's Star even further out than the Super-Earth. "The new data does show evidence for a long period object. That object... has a very low probability of being the van de Kamp planet.

But it's a long shot," said Anglada Escudé. In a separate article published in Nature, Rodrigo Diaz, from the Institute of Astronomy and Space Physics in Buenos Aires, Argentina, who was not involved with the study, said the discovery "gives us a key piece in the puzzle of planetary formation and evolution, and might be among the first low-mass exoplanets whose atmospheres are probed in detail".

 He added: "Difficult detections such as this one warrant confirmation by independent methods and research groups... a signal for the planet might be detectable in astrometric data - precision measurements of stellar positions - from the Gaia space observatory that are expected to be released in the 2020s.

" The star is named after the American astronomer E E Barnard, who measured properties of its motion in 1916.  

Water found for first time on 'potentially habitable' planet

Astronomers have for the first time discovered water in the atmosphere of a planet orbiting within the habitable zone of a distant star.

The finding makes the world - which is called K2-18b - a plausible candidate in the search for alien life.

 Within 10 years, new space telescopes might be able to determine whether K2-18b's atmosphere contains gases that could be produced by living organisms.

 Details were published in the scientific journalNature Astronomy .

 The lead scientist, Prof Giovanna Tinetti of University College London (UCL), described the discovery as "mind blowing". "This is the first time that we have detected water on a planet in the habitable zone around a star where the temperature is potentially compatible with the presence of life," she said.

 The habitable zone is the region around a star where temperatures are considered sufficiently benign for water to exist in liquid form on the surface of a planet. The new planet is just over twice the size of Earth - in a planet category known as a "super Earth" - and has a temperature cool enough to have liquid water, between zero and 40C. K2-18b is 111 light-years - about 650 million million miles - from Earth,

too far to send a probe. So the only option is to wait for the next generation of space telescopes to be launched in the 2020s and to look for gases in the planet's atmosphere that could only be produced by living organisms.

 What is an exoplanet?

Planets beyond our Solar System are called exoplanets

1. The first exoplanet was discovered in 1992, orbiting a pulsar (a neutron star that emits electromagnetic radiation)

2. More than 4,000 have been detected to date using several techniques

3. Many of these worlds are large planets believed to resemble Jupiter or Neptune

4. Many giant planets have been found orbiting very close to their stars


The team behind the discovery looked through the planets discovered by the Hubble Space Telescope between 2016 and 2017.

The researchers determined some of the chemicals in their atmosphere by studying the changes to the starlight as the planets orbited their suns.

The light filtered through the planets' atmospheres was subtly altered by the composition of the atmosphere.

 Only K2-18b revealed the molecular signature of water, which is a vital ingredient for life on Earth. Dr Angelos Tsiaras, a member of the UCL team, said that finding water in the atmosphere of a "potentially habitable exoplanet was incredibly exciting". Other astronomers, however, dispute the claim that the planet is potentially habitable.

One analysis indicates that planets that are 1.5 times the mass of the Earth are unlikely to have a rocky surface. There is also concern that K2-18b's size and gravity would make it difficult for the world to support life.

 Other critics suggest that the planet should not be classified as a super-Earth, but as a mini Neptune instead. This is a class of planet that is typically more massive than a super-Earth (it includes worlds that are up to 10 times the mass of our own planet).

Prof Tinetti, however, maintains her view that the new world is potentially habitable. She said it had a mean density that's comparable to that of Mars (which is composed of silicates) and Jupiter's moon Europa, and much higher than Neptune's. "K2-18b cannot be classified as a mini-Neptune,

it is more likely to be a planet with an interior of rock and ices. These types of planets, [are] sometimes called 'ocean planets'," she told BBC News. "Now, whether this planet really has an ocean at the surface or rock,

we cannot tell with current observations, but having water in the atmosphere is a good start." But it is a view that Dr Laura Kreidberg, of the Centre for Astrophysics at Harvard University does not agree with.

 
The interior of the planet is much more like Neptune. Pressure and temperature increase with depth, so that before a rocky surface is reached, it is too hot and too high-pressure for complex molecules like DNA or any of the other building blocks of life to form," she told BBC News. Prof David Charbonneau, also from Harvard University, said the fact that K2-18b's atmosphere was detected was proof in itself that it could not support life. "If the planet had a thin secondary atmosphere similar to Earth it would be so thin that Hubble couldn't detect it."

  Another issue is that astronomers can't agree what conditions are needed for habitability. We only have the Earth to go on but life may also be possible on other types of worlds

 It is likely to require a survey of the chemical composition of, perhaps, hundreds of worlds and an understanding of how they are created and evolve, according to Prof Tinetti.

 "The Earth really stands out in our own Solar System. It has oxygen, water and ozone. But if we find all that around a planet around a distant star we have to be cautious about saying that it supports life," she said.

 "This is why we need to understand not just a handful of planets in the galaxy but hundreds of them. And what we hope is that the habitable planets will stand out,

that we will see a big difference between the planets that are habitable and the ones that are not."