Lunar encore

Lunar encore
by Staff Writers
Paris (ESA) Jul 20, 2023

Happy international Moon day! Today marks the annual celebration of the Apollo 11 lunar landing on 20 July, in 1969. More than fifty years later, during the Artemis I mission on 28 November 2022, this image was captured by a camera placed on the tip of one of the European Service Module's four solar array wings, part of the Orion spacecraft.

The frame shows the Orion spacecraft on the left with one solar wing extending from the European Service Module to the right, dividing Earth (above) and the Moon. The cones on the European Service Module are the thrusters for the engines the spacecraft has for propulsion. The smaller cones on the side, in groups of four are part of the reaction control system used to orient the spacecraft, and the larger ones facing the camera grouped by two are the auxiliary thrusters.

Artemis I is the first in a series of missions to propel humankind forward to the Moon and beyond. The Artemis programme aims to establish permanent stations and outposts in orbit around our natural satellite. During the Artemis I test flight, the Orion spacecraft flew without astronauts. NASA provided the rocket and the crew capsule and ESA the European Service Module - Orion's 'powerhouse'.

The test flight allowed mission control at NASA's Johnson Space Center to get a feel for the spacecraft and push it to the limits of its capabilities. To everyone's delight Orion exceeded all expectations. For the European experts who worked on the European Service Module, the mission was even more rewarding due to the live view of the commands provided by the cameras on board.

The primary purpose of the cameras was self-observation: to monitor the spacecraft on its two-week mission around the Moon. "As engineers we are lucky to have the livestream and high-quality photos, as they are rare, most satellites don't take selfies," says Thales Alenia Space's Lorenzo Andrioli, "To see those images of Orion flying by the Moon and to think you have touched those components is a very special feeling."

Orion was equipped with 16 strategically placed cameras across its structure, with one at the end of each of the four solar array wings. The wing cameras were especially versatile. The solar arrays were designed to swivel, pivot and rotate to capture as much sunlight as possible. During the test flight, they could also be repositioned to capture better views of the Moon. On occasion, the entire spacecraft was rotated to get extraordinary shots.

The European Service Module played a crucial role in enabling these photos. It consumed less fuel while also generating more electricity than required for the mission. The surplus of energy allowed for the repositioning of the spacecraft and solar wings.

Each operation in space requires close coordination between the spacecraft systems: electrical power, propulsion, thermal and data handling. Changing one parameter has immediate effects on the others, for example moving the solar panels would change the amount of electricity generated, and adjusting the spacecraft may necessitate the thermal team's preparation of heaters to maintain optimal operating temperatures.

With this resounding success, all is set for Artemis II which will see four astronauts orbit the Moon and return to Earth. NASA's commander Reid Wiseman, pilot Victor Glover and mission specialist Christina Koch, together with Canadian Space Agency astronaut Jeremy Hansen will embark on this exciting mission in 2024.