Rosetta (spacecraft)

Rosetta (spacecraft)
Name	Rosetta
Mission type	Comet orbiter/lander
Operator	European Space Agency
COSPAR ID	2004-006A
SATCAT	28169
Mission duration	Planned: 12 years, Final: 12 years, 6 months, 28 days
Spacecraft	Rosetta
Manufacturer	Astrium
Launch mass	2,900 kg (6,400 lb)
Power	850 watts
Launch date	2 March 2004, 07:17 UTC
Launch rocket	Ariane 5 G+
Launch site	Guiana Space Centre ELA-3
Last contact	30 September 2016
Interplanetary	* Flyby of Mars (2007) * Flybys of 2867 Šteins (2008) and 21 Lutetia (2010) * Rendezvous with 67P/Churyumov–Gerasimenko (2014) * Deployment of Philae (2014)
Insignia caption	Mission patch

Rosetta (spacecraft) was a pioneering robotic space probe developed and operated by the European Space Agency (ESA) to perform a detailed study of comet 67P/Churyumov–Gerasimenko. As the cornerstone mission of ESA's Horizon 2000 program, it became the first spacecraft to orbit a comet and deploy a lander to its surface. The mission's data has fundamentally transformed scientific understanding of comets, providing unprecedented insights into the composition of the early Solar System.

Mission overview

Approved in November 1993, the Rosetta mission was designed to chase, orbit, and land on a comet, a feat never before attempted. The primary objective was to understand the origin and evolution of the Solar System by examining the pristine, icy material of a comet nucleus. Managed from the European Space Operations Centre (ESOC) in Darmstadt, the mission involved a large consortium of scientific institutions across Europe and NASA, which contributed several key instruments. The ambitious plan required a complex 10-year journey through the inner Solar System, utilizing multiple gravity assist maneuvers to reach its target.

Spacecraft design

The Rosetta orbiter was a large, box-shaped satellite bus with two 14-meter-long solar panels, necessary to generate sufficient power far from the Sun. The main structure was built by Astrium (now Airbus Defence and Space) in Friedrichshafen. Key subsystems included a high-gain antenna for communication with Earth, a propulsion module with 24 bipropellant thrusters for trajectory corrections, and a sophisticated attitude control system. The spacecraft was designed to operate in the harsh thermal environment of deep space and in the dusty coma of an active comet, requiring robust shielding and fault-protection software.

Scientific instruments

Rosetta carried a suite of eleven scientific instruments to analyze the comet from orbit. These included the ALICE ultraviolet spectrometer, the OSIRIS camera system, the VIRTIS visible and infrared spectrometer, and the MIRO microwave instrument for studying the comet's nucleus and coma. Other instruments, like ROSINA and COSIMA, analyzed the composition of gases and dust grains, while CONSERT used radio waves to probe the comet's internal structure. The Philae lander carried an additional ten instruments for in-situ surface measurements.

Journey to comet 67P

Launched on 2 March 2004 aboard an Ariane 5 rocket from the Guiana Space Centre, Rosetta began a circuitous 6.4-billion-kilometer voyage. It performed gravity-assist flybys of Mars in February 2007 and Earth three times (2005, 2007, 2009). During its cruise, it successfully flew past and imaged asteroids 2867 Šteins in September 2008 and 21 Lutetia in July 2010. The spacecraft entered a 31-month period of deep-space hibernation in June 2011 to conserve power, waking as planned in January 2014 before its final approach to comet 67P/Churyumov–Gerasimenko.

Philae lander

On 12 November 2014, Rosetta released the Philae lander, which descended to the surface of the comet. Anchoring harpoons failed to fire, causing Philae to bounce and come to rest in a shaded area named Abydos on the smaller lobe of the comet. Despite limited sunlight for its solar panels, Philae operated for about 60 hours, returning valuable data from instruments like SD2 and Ptolemy before entering hibernation. Brief contact was re-established in June 2015 as the comet approached the Sun, but the lander was never fully recovered.

Key discoveries

Rosetta's observations revolutionized comet science, revealing 67P/Churyumov–Gerasimenko as a dark, dusty, and highly porous "rubber duck"-shaped body with a diverse landscape of cliffs, pits, and boulders. The ROSINA instrument detected molecular oxygen and nitrogen, while the ratio of deuterium to hydrogen in the comet's water was found to be distinct from Earth's, challenging theories that comets delivered our planet's oceans. The COSIMA instrument identified complex organic molecules, including the amino acid glycine, strengthening the link between comets and the prebiotic chemistry necessary for life.

End of mission

As comet 67P receded from the Sun, power to Rosetta's instruments diminished. ESA mission planners designed a controlled descent to the comet's surface in the Ma'at region on 30 September 2016. During its final hours, Rosetta took extremely high-resolution images and made unique scientific measurements from close range. The impact was commanded to ensure the spacecraft could not accidentally contact Earth in the future, with the final signal received at the European Space Operations Centre at 11:19 UTC, marking the end of one of the most successful deep-space missions in history.

Category:European Space Agency spacecraft Category:Comet missions Category:Space probes launched in 2004