In 2004, the European Space Agency launched the satellite Rosetta to complete an ambitious mission: not only was Rosetta to travel approximately 4 billion miles, make three gravity-assist flybys of Earth and one of Mars in order to make a precision rendezvous with a comet hurtling through space, but also then land on the comet.

“After ten years, five months and four days travelling towards our destination, looping around the Sun five times and clocking up 6.4 billion kilometres (3.9 billion miles), we are delighted to announce finally ‘we are here’,” said Jean-Jacques Dordain, ESA’s Director General in a statement.

In January 2014, Rosetta ‘woke up’ from deep space hibernation to prepare its approach to the comet 67P/Churyumov–Gerasimenko (C-G). Following wake-up, the orbiter’s 11 science instruments and 10 lander instruments were reactivated and readied for scientific observations.

Upon Rosetta’s final approach, beginning in early May, operators executed 10 orbital correction maneuvers. These critical maneuvers positioned the spacecraft to enter orbit of the comet and reduced the its velocity with respect to the comet from 775 m/s (1,733.62 mph) to 1 m/s (2.23 mph), a speed equivalent to walking pace. After the last maneuver August 6, Rosetta rendezvoused with C-G and entered into orbit.

“Arriving at the comet is really only just the beginning of an even bigger adventure, with greater challenges still to come as we learn how to operate in this unchartered environment, start to orbit and, eventually, land,” said Sylvain Lodiot, ESA’s Rosetta spacecraft operations manager.

There are multiple factors ESA scientists must consider when attempting a real-life version of Lunar Lander. Low gravity will be an issue, and teams studied potential landing procedures at the Max Planck Institute in Katlenburg-Lindau before launching.

Another potential pitfall will be the terrain of the comet. A sloped or inclined topography could prove dire, and even on a flat surface the satellite may experience technical difficulties. If the surface is too hard Rosetta could bounce off of the surface, damaging instruments and result in mission failure. Alternatively if the ground is too sandy, the spacecraft could sink or settle in a manner that obstructs subsequent data collection. To err on the side of caution, scientists equipped the satellite with harpoons and ice screws to be prepared for landing no matter what the terrain and environment.

Stefan Ulamec, Philae Lander Manager is confident that the slow approach speed will negate any possible malfunctions, “this is like walking and bouncing against a wall; it hurts but it won’t kill you!” he said during a Rosetta discussion on Friday.

The landing site selection group convenes from August 22-24, and will determine five potential landing sites then before determining a final landing spot in mid-September. After landing, scientists can begin the next great phase of the mission: exploring and gathering information from a moving comet.

“After landing, Rosetta will continue to accompany the comet until its closest approach to the Sun in August 2015 and beyond, watching its behavior from close quarters to give us a unique insight and real-time experience of how a comet works as it hurtles around the Sun.” said Matt Taylor, ESA Rosetta project scientist.