with the 30 sections of each solar array, provide a regulated 28 V bus, distribute this power via protected outputs and to handle the battery charging and discharging. For Herschel, the solar array is fixed on the bottom part of the baffle designed to protect the cryostat from the Sun. The three-axis attitude control system maintains this baffle in direction of the Sun. The top part of this baffle is covered with optical solar reflector (OSR) mirrors reflecting 98% of the Sun's energy, avoiding heating of the cryostat. Attitude and orbit control This function is performed by the attitude control computer (ACC) which is the platform for the ACMS. It is designed to fulfil the pointing and slewing requirements of the Herschel and Planck payload. The Herschel spacecraft is three-axis stabilized. The absolute pointing error needs to be less than 3.7 arc seconds. The main sensor of the line of sight in both spacecraft is the star tracker. Launch and orbit The spacecraft, built in the Cannes Mandelieu Space Center, under Thales Alenia Space Contractorship, was successfully launched from the Guiana Space Centre in French Guiana at 13:12:02 UTC on 14 May 2009, aboard an Ariane 5 rocket, along with the Planck spacecraft, and placed on a very elliptical orbit on its way towards the second Lagrangian point. The orbit's perigee was 270.0 km (intended ), apogee 1,197,080 km (intended ), inclination 5.99 deg (intended ). On 14 June 2009, ESA successfully sent the command for the cryocover to open which allowed the PACS system to see the sky and transmit images in a few weeks. The lid had to remain closed until the telescope was well into space to prevent contamination. Five days later the first set of test photos, depicting M51 Group, was published by ESA. In mid-July 2009, approximately sixty days after launch, it entered a halo orbit of 800,000 km average radius around the second Lagrangian point (L2) of the Earth-Sun system, 1.5 million kilometres from the Earth. Discoveries On 21 July 2009, Herschel commissioning was declared successful, allowing the start of the operational phase. A formal handover of the overall responsibility of Herschel was declared from the programme manager Thomas Passvogel to the mission manager Johannes Riedinger. Herschel was instrumental in the discovery of an unknown and unexpected step in the star forming process. The initial confirmation and later verification via help from ground-based telescopes