Rosetta and Philae
First spacecraft to orbit and land on a comet.
The Rosetta mission, a cornerstone of the European Space Agency’s Horizon 2000 programme, launched in March 2004 aboard an Ariane 5 rocket. Its primary objective was a detailed study of comet 67P/Churyumov–Gerasimenko, a goal it achieved through both an orbiter and a lander module named Philae. The spacecraft’s journey included gravity-assist flybys of Earth and Mars, as well as encounters with the asteroids 2867 Šteins and 21 Lutetia. After reaching the comet in August 2014, Rosetta became the first spacecraft to orbit a comet nucleus. In November of that year, Philae performed the first successful soft landing on a comet, though its battery depleted two days later. Brief communication with the lander was re-established in mid-2015, but the orbiter’s communications module was eventually deactivated in July 2016. The mission concluded in September 2016 with Rosetta’s controlled hard landing on the comet’s Ma’at region. The total cost of the mission was approximately €1.3 billion. The probe’s name referenced the Rosetta Stone, while the lander was named after the Philae obelisk, both key artifacts in deciphering Egyptian hieroglyphs, symbolizing the mission’s goal of unlocking cometary secrets. The spacecraft carried a micro-etched nickel disc containing thousands of language translations. The mission achieved numerous firsts, including the first European close encounters with asteroids, the first use of solar cells as a primary power source near Jupiter’s orbit, and the first on-site analysis of a comet’s surface composition. Its history traces back to earlier comet missions like Giotto, with the project evolving from a planned sample-return mission into a rendezvous and lander mission after NASA’s cancellation of a similar project.
- field
- Space exploration, cometary science
- nationality
- European Space Agency
- known_for
- First spacecraft to orbit a comet; first soft landing on a comet nucleus
Lore & Background
The Rosetta spacecraft was a box-shaped orbiter built by the European Space Agency, carrying the Philae lander module. Philae was a small, robotic lander designed to detach from the orbiter and touch down on a comet. The mission’s primary target was comet 67P/Churyumov–Gerasimenko, a frozen body that orbits the Sun. Rosetta’s defining characteristic was its ability to perform the first-ever orbit of a comet nucleus, and Philae achieved the first controlled landing on a comet’s surface. The spacecraft’s journey included flybys of Earth, Mars, and the asteroids 21 Lutetia and 2867 Šteins. Rosetta was powered by solar cells, making it the first spacecraft to operate near Jupiter’s orbit using this energy source. Its instruments, twelve on the orbiter and nine on the lander, were designed for detailed study of the comet’s composition and activity. The mission concluded with Rosetta’s hard landing on the comet in the Ma’at region. The names Rosetta and Philae were chosen in reference to the Rosetta Stone and the Philae obelisk, ancient inscriptions that helped decipher Egyptian hieroglyphs, symbolizing the mission’s goal of unlocking secrets of the early Solar System.
Reader's Guide
It achieved many historic firsts: it was the first spacecraft to orbit a comet nucleus, the first to fly alongside a comet as it headed towards the inner Solar System, and the first to examine at close proximity the activity of a frozen comet as it is warmed by the Sun. The Philae lander obtained the first images from a comet's surface and made the first on-site analysis of its composition. The mission's name was inspired by the Rosetta Stone, reflecting the hope that the spacecraft would help decipher the early Solar System, much as the stone helped decipher Egyptian hieroglyphs. Its legacy includes a detailed study of a comet that continues to inform understanding of cometary composition and Solar System formation.
Did You Know?
- Rosetta was the first spacecraft to orbit a comet nucleus.
- The total cost of the mission was about €1.3 billion (US$1.8 billion).
More in Space Missions 1-22
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