Esa reveals Rosetta is in 'perfect orbit' after first systems check ahead of historic comet landing Has passed its first of four system checks and is in 'perfect orbit' After a four billion mile journey, the probe is now 19 miles (30 km) away At 08.35 GMT tomorrow, engineers will attempt to land a probe on 67P If all goes to plan, Philae will send a signal back to Earth at 4pm GMT 'This, for me, is a wonderful dream come true,' mission director Paolo Ferri told MailOnline. Engineers at Rosetta mission control are anxiously counting down the hours before they attempt to make space history. At 08.35 GMT tomorrow, the team in Darmstadt, Germany, will send a command to release the Philae probe from Rosetta's grip. The probe will then be in free fall for seven hours, before landing on the icy surface of comet 67P/Churyumov-Gerasimenko. Scroll down for video, animation and a live feed from mission control At 08.35 GMT tomorrow, mission control in Darmstadt, Germany will send a command to release the Philae probe from Rosetta's grip. This picture shows the boulder-strewn neck region of Comet 67P/ChuryumovñGerasimenko. It was captured around 4.8 miles (7.7km) from the surface of the comet If all goes to plan, Philae should send a signal back to mission control engineers at around 4pm GMT. The comet is currently 300 million miles away (480 million km), and is travelling through space at about 34,000 mph (55,000 km/h). Flight managers gave their OK to the first of four checks that must be carried out before the probe Philae can descend from its orbiter craft onto a comet in deep space this afternoon. 'We got the first go, the first go-ahead,' an ESA spokeswoman said at mission control in Darmstadt, Germany. The satellite is in perfect orbit. The checklist was preceded by a brief moment of worry when Philae 'took a bit longer than expected' to be activated, said Paolo Ferri, mission leader at Darmstadt. We were a bit worried at first that the temperature would be wrong (for the descent) but it all worked out. We didn't lose any time,' Ferri said. 'The robot's batteries should be charged up by tonight.' No one has ever attempted such a daring feat, and even Esa engineers admit they initially thought it sounded more like science fiction. If they manage it, Rosetta and Philae could help unravel secrets of how the solar system formed 4.5 billion years ago. Engineers at Rosetta mission control are anxiously counting down the hours before they attempt to make space history by landing the Philae probe on comet 67P. Pictured is an artist's impression Rosetta might not release Philae at the right spot if the thrusters are activated at the wrong time. Jets of gas spewing from the comet could also cause problems during the descent, moving Philae off course. Another concern is the strange duck-shape of the comet, that means Philae could crash on landing, damaging its instruments. And even if Philae lands safely, it will need to attach itself to the comet using harpoons so that it does not fly off into space. Philae could also become too hot to operate as the comet travels towards the sun. Scientist say it will be able to withstand temperatures of 150°C. Rosetta has chased comet 67P/Churyumov-Gerasimenko through space for more than ten years in what has been described as 'the sexiest, most fantastic mission ever'. After a four billion mile (6.5 billion km) journey, it is now positioned in an orbit 19 miles (30 km) away from 67P. Emotions at mission control are already running high. 'This, for me, is a wonderful dream come true,' Paolo Ferri, mission director told MailOnline. It's not fair to compare it to a relationship with a human, but it's very close.' When it was launched in 2004, Rosetta was so far from 67P that it had to pass Earth three times and Mars once, so that it could use the planets' gravity to slingshot its way deep into the solar system. The spacecraft will spend more than a year studying the comet, which is made up of material left over from when our solar system was first created 4.5 billion years ago. Ahead of the landing, Esa has published a series 'beauty shots', taken by Rosetta's navigation camera, revealing the varied and dramatic terrain of the mysterious rock. The images shows a raised plateau on the larger lobe of Comet 67P/ChuryumovñGerasimenko. It was captured from a distance of 6 miles (9.8 km) from the center of the comet Incredibly, many of the images were taken at less than six miles (10km) from the comet's surface, and highlight what a challenging task Philae engineers have ahead of them. The Philae probe aims to analyse the comet in more detail than Rosetta ever could. As Philae descends, it will be travelling at walking speed of 3ft (one metre) per second relative to 67P while the duck-shaped rock is rotating constantly. Philae will need to be released with pinpoint accuracy as its landing site contains a mix of sheer cliffs and deep craters - any of which could scupper its chances. Scientists are aiming to land on a spot named 'Agilkia' on the smaller 'head' lobe of 67P after Philae is released from a distance of 14 miles (22.5km) from the centre of 67P. This image shows the Agilkia landing site on Comet 67P/ChuryumovGerasimenko, taken with Rosetta's navigation camera on 6 November. It was captured at a distance of 22 miles (35.5km) Jose Pellon-Bailon, one of eight flight engineers responsible for Rosetta, told MailOnline his team will have to make a series of Go or No-Go decisions before the landing. There are a number of things that could go wrong. For instance, Rosetta might not release Philae at the right spot if the thrusters are activated at the wrong time. Another concern is the strange duck-shape of the comet, which means Philae could crash land, damaging its instruments. And even if Philae lands safely, it will need to attach itself to the comet using harpoons. Philae is able to withstand temperatures of 150°C, but it could become too hot to operate as the comet travels towards the sun. If the green light is given on the landing, communication between Rosetta and mission control will take 28 minutes and 20 seconds each way - the time it takes for a signal to travel 315 million miles (510 million km) to Earth. 'It's difficult, in the sense that you are commanding something and you are seeing the effects almost one hour later,' says Pellon-Bailon. Ferri's biggest fear isn't that Philae will be damaged during the descent, but that it could fail to send a signal back at all. As its ices evaporate, instruments on board the orbiter will study the dust and gas particles that surround the comet and trail behind it The landing has been described by Esa as 'ridiculously difficult'. 'Imagine the comet as Mont Blanc,' says Ferri. Pellon-Bailon says his team are fully prepared, even down to what they will eat on the day. But it has been possible, and even if Philae doesn't make it on tomorrow, the mission has already achieved its main objective.