The European Space Agency's Planck satellite has just reached a critical point in its mission, as it got nearly halfway to its destination, the Lagrangian point L2. The delicate observatory has already started making a series of maneuvers in space, all aimed at pushing it onto the correct path to the L2. The moves were very delicate, and even the slightest inaccuracy could have sent the craft to another destination. The most important of the maneuvers began at 19:28 CEST on June 5th, and lasted for about 30 hours.

During this time, the spacecraft fired short “pulse burns,” lighting its engines for only six seconds each minute. These limitations were caused by the fact that Planck was slowly moving at one rotation per minute as it traveled in space, and also because the thrusters on it were not adjustable. This means that they can only fire when the rotation of the craft brings them in the correct position, which only happens for six seconds each minute.

A speed change of an estimated 550.8 kilometers/hour occurred following this stage of the mission, as opposed to the speed the craft have up until June 5th, of 105 840 km/hour, referenced to the Sun. Before the thruster burns began, the observatory was already 1.19 million kilometers away from Earth. According to ESA, the satellite needs to travel about 1.5 million kilometers to its destination, which it is scheduled to reach in July.

“Throughout the maneuver, we will closely monitor the spacecraft behavior and its dynamical state. Once the maneuver is complete, sometime late on Saturday, the Flight Dynamics team will analyze the burn performance and determine Planck's new orbit. Based on the results, we also have a slot available for a 'touch-up' maneuver on 17 June,” Matthias Muck, who is the Planck Flight Dynamics specialist at ESA's European Space Operations Center (ESOC), in Darmstadt, Germany, said before the delicate operations took place.

After the June 17th maneuver, only a single one remains before the end of its journey. In early July, it will have to light up its thrusters again, in a move that will take it on a stable orbit around the L2 point, at about 400,000 kilometers, ScienceDaily informs. Planck is the first European-built satellite exclusively dedicated to studying the Cosmic Microwave Background. The observatory, together with the Herschel telescope, blasted off from the Kourou Space Center in the French Guyana, South America, on May 14th, aboard an Ariane 5 delivery system.