Story highlights If successful, the Rosetta mission will be the first to orbit and land on a comet

Scientists hope to learn more about the composition of comets

The robotic lander Philae is due to touch down in November

Could comets have brought water to the Earth? Rosetta may help answer the question

After a 10-year chase taking it billions of miles across the solar system, the Rosetta spacecraft is homing in on its close encounter with a comet.

Pictures of the oddly-shaped rock have already been returned but on Wednesday scientists at the European Space Agency , which is leading the project, say they hope to see images from within about 75 miles as the probe carries out the last of its braking maneuvers.

If successful, the mission will notch up a series of firsts. Rosetta will be the first spacecraft to orbit a comet on its journey around the sun, and in November mission controllers aim to place the robotic lander Philae on the surface -- something that has never been done before.

Previous missions have performed comet fly-bys but Rosetta is different. This probe will follow the comet for more than a year, mapping and measuring how it changes as it is blasted by the sun's energy.

Photos: Rosetta: The comet chaser Photos: Rosetta: The comet chaser The Rosetta probe sent an unexpected final image back to Earth shortly before it made a controlled impact onto the surface of Comet 67P last September. Hide Caption 1 of 40 Photos: Rosetta: The comet chaser Philae has been found! – The Rosetta spacecraft's high-resolution camera took this image of the Philae lander on September 2, 2016. The lander is wedged into a dark crack on a comet, named 67P/Churyumov--Gerasimenko, hurtling through space. The discovery comes less than a month before the Rosetta mission's end. Hide Caption 2 of 40 Photos: Rosetta: The comet chaser Philae is wedged in a dark corner of Rosetta – "We are so happy to have finally imaged Philae, and to see it in such amazing detail," says Cecilia Tubiana of the OSIRIS camera team. She was the first person to see the images when they were downlinked from the Rosetta probe, according to the European Space Agency. Hide Caption 3 of 40 Photos: Rosetta: The comet chaser Philae found using images from Rosetta – The image is detailed enough that viewers can pick out features of Philae's 3-foot-wide (1 meter) body. Even two of its three legs can be seen. Hide Caption 4 of 40 Photos: Rosetta: The comet chaser One of the primary objectives of the Rosetta mission was to drop the Philae lander onto the comet. The probe was successfully deployed in November 2014, becoming the first probe to land on a comet. But Philae failed to grab onto the comet and bounced around. It fell silent a few days later. Then on June 13, 2015, Philae came out of hibernation and "spoke" to mission managers at the European Space Agency for 85 seconds. This photo above was taken by the lander's mothership, the Rosetta orbiter, after the lander started its descent to the comet. Hide Caption 5 of 40 Photos: Rosetta: The comet chaser The Rosetta spacecraft captured this image of a jet of white debris spraying from Comet 67P/Churyumov--Gerasimenko on July 29, 2015. Mission scientists said this was the brightest jet seen to date in the mission. The debris is mostly of ice coated with dark organic material. Hide Caption 6 of 40 Photos: Rosetta: The comet chaser This image of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta on July 8, 2015 as the spacecraft and comet headed toward their closest approach to the sun. Rosetta was about 125 miles (201 kilometers) from the comet when it took this image. Hide Caption 7 of 40 Photos: Rosetta: The comet chaser Philae wakes up! Mission managers posted this cartoon of the lander yawning after it came out of hibernation on June 13, 2015. They also sent a series of tweets between the lander and its mothership, Rosetta. Hide Caption 8 of 40 Photos: Rosetta: The comet chaser Comet 67P/Churyumov-Gerasimenko is a Jupiter-family comet. Its 6.5 year journey around the Sun takes it from just beyond the orbit of Jupiter at its most distant, to between the orbits of Earth and Mars at its closest. The comet hails from the Kuiper Belt, but gravitational perturbations knocked it towards the Sun where interactions with Jupiter's gravity set it on its present-day orbit. Hide Caption 9 of 40 Photos: Rosetta: The comet chaser This image of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta on June 5, 2015, while the spacecraft was about 129 miles (208 kilometers) from the comet's center. Hide Caption 10 of 40 Photos: Rosetta: The comet chaser Rosetta's navigation camera took this image of the comet on June 1, 2015. Hide Caption 11 of 40 Photos: Rosetta: The comet chaser The Rosetta Mission is tracking Comet 67P/Churyumov-Gerasimenko on its orbit around the sun. This image was taken on May 3, 2015 at a distance of about 84 miles (135 km) from the comet's center. Hide Caption 12 of 40 Photos: Rosetta: The comet chaser This image of Comet 67P/Churyumov-Gerasimenko was taken on April 15, 2015. Hide Caption 13 of 40 Photos: Rosetta: The comet chaser Rosetta snapped this wide-angle view of Comet 67P/Churyumov-Gerasimenko in September 2014. Rosetta was about 107 million miles (172 million kilometers) from Earth and about 92 million miles (148 million kilometers) from the sun when the photo was released. Hide Caption 14 of 40 Photos: Rosetta: The comet chaser A camera on Rosetta took this picture of Comet 67P/Churyumov-Gerasimenko on November 22, 2014, from a distance of about 19 miles (31 kilometers). The nucleus is deliberately overexposed to reveal jets of material spewing from the comet. The 2.5-mile-wide (4-kilometer) comet has shown a big increase in the amount of water its releasing, according to NASA. The space agency says about 40 ounces (1.2 liters) of water was being sprayed into space every second at the end of August 2014. Hide Caption 15 of 40 Photos: Rosetta: The comet chaser Rosetta took this picture of a section of the comet's two lobes from a distance of about 5 miles (8 kilometers) on October 14, 2014. Hide Caption 16 of 40 Photos: Rosetta: The comet chaser The Rosetta spacecraft's Philae lander is shown sitting on Comet 67P/Churyumov-Gerasimenko after becoming the first space probe to land on a comet on November 12, 2014. The probe's harpoons failed to fire, and Philae bounced a few times. The lander was able to send back images and data for 57 hours before losing power. Hide Caption 17 of 40 Photos: Rosetta: The comet chaser Rosetta's lander, Philae, wasn't able to get a good grip on the comet after it touched down. This mosaic shows Philae's movements as it bounced across the comet. Hide Caption 18 of 40 Photos: Rosetta: The comet chaser Philae snapped these images after landing, and mission scientists used them to create a panoramic view of the landing site. A graphic shows where the probe would be sitting in the photograph. Hide Caption 19 of 40 Photos: Rosetta: The comet chaser The image of Comet 67P/Churyumov-Gerasimenko was taken by a camera on the Philae lander during its descent to the comet on November 12, 2014. The lander was about 1.9 miles (3 kilometers) from the surface at the time. Philae touched down on the comet about seven hours later. Hide Caption 20 of 40 Photos: Rosetta: The comet chaser Rosetta's OSIRIS camera captured this parting shot of the Philae lander after separation. Hide Caption 21 of 40 Photos: Rosetta: The comet chaser Rosetta's lander Philae took this parting shot of its mother ship shortly after separation on November 12, 2014, as Philae headed for a landing on Comet 67P. While Philae is the first probe to land on a comet , Rosetta is the first to rendezvous with a comet and follow it around the sun. Hide Caption 22 of 40 Photos: Rosetta: The comet chaser This mosaic is made of four individual images taken about 20 miles (31.8 kilometers ) from the center of the comet on November 4, 2014. Hide Caption 23 of 40 Photos: Rosetta: The comet chaser Rosetta took this image of comet 67P/Churyumov-Gerasimenko on September 15, 2014. The box on the right shows where the lander was expected to touch down. Hide Caption 24 of 40 Photos: Rosetta: The comet chaser The spacecraft sent this image as it approached the comet on August 6, 2014. From a distance of nearly 81 miles (130 kilometers), it reveals detail of the smooth region on the comet's "body" section. Hide Caption 25 of 40 Photos: Rosetta: The comet chaser This image, captured August 7, 2014, shows the diversity of surface structures on the comet's nucleus. Hide Caption 26 of 40 Photos: Rosetta: The comet chaser The comet's "head" can be seen in the left of the frame as it casts a shadow over the "body" in this image released August 6, 2014. Hide Caption 27 of 40 Photos: Rosetta: The comet chaser This image of the comet was taken on August 1, 2014, as Rosetta closed in its target. Hide Caption 28 of 40 Photos: Rosetta: The comet chaser Rosetta's mission started on March 2, 2004, when it was launched on a European Ariane 5 rocket from Kourou, French Guiana. Hide Caption 29 of 40 Photos: Rosetta: The comet chaser Rosetta is named after the Rosetta Stone, the black basalt that provided the key to deciphering Egyptian hieroglyphs. Scientists think the mission will give them new clues about the origins of the solar system and life on Earth. The mission is spearheaded by the European Space Agency with key support from NASA. Hide Caption 30 of 40 Photos: Rosetta: The comet chaser This photo shows Rosetta being tested before it was wrapped in insulating blankets and loaded on a rocket for launch. Hide Caption 31 of 40 Photos: Rosetta: The comet chaser Rosetta has massive solar wings to power the spacecraft. They were unfurled and checked out at the European Space Agency's test facilities before being packed up for liftoff. Hide Caption 32 of 40 Photos: Rosetta: The comet chaser After its closest approach to Earth in November 2007, Rosetta captured this image of the planet. Hide Caption 33 of 40 Photos: Rosetta: The comet chaser Rosetta snapped this image of Earth in November 2009. The spacecraft was 393,328 miles from Earth. Hide Caption 34 of 40 Photos: Rosetta: The comet chaser Rosetta passed asteroid Steins in September 2008, giving scientists amazing close-ups of the asteroid's huge crater. The asteroid is about 3 miles in diameter. Hide Caption 35 of 40 Photos: Rosetta: The comet chaser Rosetta took this image of Mars as it looped through the solar system. Hide Caption 36 of 40 Photos: Rosetta: The comet chaser This image was taken by an instrument on Rosetta's Philae lander just minutes before the spacecraft made its closest approach to Mars. Part of Rosetta and its solar arrays are visible. Hide Caption 37 of 40 Photos: Rosetta: The comet chaser On July 10, 2010, Rosetta flew about 1,864 miles from asteroid Lutetia, which is 10 times larger than asteroid Steins. Hide Caption 38 of 40 Photos: Rosetta: The comet chaser Look closely at the top of this picture. See that dot? That's Saturn. Rosetta snapped the picture of asteroid Lutetia and captured Saturn in the background. Hide Caption 39 of 40 Photos: Rosetta: The comet chaser After taking pictures of Earth, Mars and asteroids, Rosetta was put into hibernation in May 2011 after it reached the outer part of the solar system. Mission managers woke it January 20, 2014. Hide Caption 40 of 40

Mission controllers had to use the gravity of Earth and Mars to give the probe a slingshot acceleration to meet its target on the right trajectory. Rosetta also had to be put into hibernation for more than two years to conserve power before being woken up successfully in January this year.

Scientists hope to learn more about the composition of comets and perhaps whether they brought water to the Earth or even the chemicals that make up the building blocks of life.

"It really is such a step forward to anything that has come before," project scientist Matt Taylor told CNN.

Rosetta will soon begin mapping the surface of Comet 67P/Churyumov-Gerasimenko and find out more about its gravitational pull. This will help to find a suitable landing site for Philae and allow engineers to keep Rosetta in the right orbit.

As comets approach the sun, any ice melts and is turned into an ionized gas tail. The dust produces a separate, curving tail. It's these processes that Rosetta scientists hope to be able to study from close proximity.

Taylor explained that the survey will show the team what the comet nucleus looks like now and when it gets closer to the sun.

"We'll be able to make a comparison to now, when its relatively inert, to when it's highly active ... making this measurement over a year when we're riding alongside at walking pace and observing how a comet works and interacts with the sun," he said.

"We are there for over a year to see this compete development to the extent that you may even be able to measure the decrease in the volume of the nucleus ... see how much material has left the comet."

Rosetta's target comet 67P/Churyumov-Gerasimenko is known as a short-period comet. It reappears every six years as its orbit brings it close to the sun. Halley's comet has a period of about 76 years and is not due to return close enough to Earth to be visible until 2061. Others only return after thousands of years.