Rosetta mission: setback as landing probe fails to respond initially Matt Taylor, a Rosetta project scientist, said: "We had a hiccup when we first powered it up. There was a little bit of a delay with it coming online. We don't know what caused it and we are seeking to find out the cause. Obviously it's a concern for the next step. But everything appears to be working OK now so we're keeping our fingers crossed. Scientists said that the craft was on the right orbit, and the Twitter feed for Philae announced that it was "definitely" warmed up after the early glitches. Comets throughout history have been associated with ill omen; harbingers of doom which streaked across the skies foretelling plague, death and apocalypse. But the Rosetta mission could prove that they are actually responsible for all of life on Earth - and possibly life beyond it as well. The scientists will be particularly excited if they find "left-handed" amino acids - so-called because they have mirror image "right-handed" forms - as those are the type which make up most of life on Earth. Finding them on a comet would not only give the strongest indication yet that we have alien ancestry, but it would show that Earth-like life could exist on other planets. John Plane, professor of atmospheric chemistry at the University of Leeds, said: "It's hugely exciting. One of the great mysteries is whether life came from comets. And if these 'left-handed" amino acids are found, then clearly these comets will be seeding other planets as well. We will be able to look in great detail at what is in the ice. There is also a theory that the icy comets brought huge amounts of water to Earth during a period of intense bombardment 4 billion years ago. Prof Stanley Cowley, of the University of Leicester's department of physics and astronomy, said: "Comets represent bodies which were left over, essentially unprocessed, from the formation of the solar system some 4.5 billion years ago. It is therefore an interesting relic from that otherwise inaccessible epoch. Comet impacts are thought to have been one of the principal means by which water was delivered to the early Earth, possibly contributing half the water in our oceans. The comet is orbiting at 34,000 miles per hour. It is 360 million miles away from Earth, about half way between the orbits of Mars and Jupiter. The surface is a jumble of cliffs, boulders and steep slopes. If Philae is released when Rosetta is just a centimetre out of alignment, the lander could fall hundreds of metres away from the chosen touchdown spot. On Tuesday night, the European Space Agency website said that Rosetta was on course to deliver the probe on the correct trajectory, thus completing the first "critical moment" of the landing. Dr Daniel Brown, an astronomy lecturer at Nottingham Trent University, said: "Although we have landed on planets, moons and asteroids, it has never been attempted for a nucleus of a comet, and with good reason. These objects have a very low gravity, are loosely composed of ice, dust and rocks, and are very irregular in shape. They are temperamental in their behaviour and notoriously difficult to predict. The probe is expected to land and fix itself to the two-mile-long comet using harpoons and drills. It will then begin to analyse the ice, organic material and chemicals present in the comet's nucleus, and later, as it gets closer to the Sun and begins to heat up, the emissions of gases such as carbon dioxide. Prof Alan Fitzsimmons from the astrophysics research centre at Queen's University, Belfast, and colleagues have spent more than a decade studying comet 67P/Churyumov-Gerasimenko and measuring its properties. "We have waited over 10 years for this day, but with the comet being over 317 million miles away, all we can do now is cross our fingers and hope," he said. The Rosetta mission realises the ambition of mankind to explore our origins and discover what is out there. The distance between Earth and the comet means that mission control will not find out whether the landing has been a success for 28 minutes and 20 seconds due to the amount of time it will take the radio waves to travel and transmit the data. While Philae is on the surface, Rosetta will continue flying in formation with the comet at a distance of about 18 miles. Rosetta has already been travelling for more than a decade. The craft was launched on March 2, 2004, from Kourou, French Guiana. It is named after the Rosetta Stone, which provided the key to deciphering hieroglyphics. Scientists hope the spacecraft will provide a similar breakthrough in our understanding of the past. The Philae probe is named after the island in the Nile where an obelisk was found which also displayed inscriptions in two ancient languages and helped with deciphering the Rosetta Stone.