September 4, 2014 – The European Space Agency (ESA) will meet with members of the press at ESA Headquarters in Paris, France on September 15 to announce the primary landing site for Rosetta’s lander Philae. The landing will mark the first time in history that a human spacecraft has touched down on the surface of a comet.
Rosetta arrived at Comet 67P/Churyumov–Gerasimenko on August 6, and since that time, mission scientists and engineers have been carefully studying possible landing sites for Philae. Choosing the right landing site is a complex process. The site must balance the technical needs of the orbiter and lander during all phases of the separation, descent, and landing, and during operations on the surface with the scientific requirements of the ten instruments on board Philae.
Five candidate locations were announced on August 25 for further investigation, in order to determine possible orbital and operational strategies for Rosetta. Rosetta’s instruments have been use to create more detailed observations of the proposed sites.
By September 14, the five candidate sites will have been assessed and ranked, leading to the selection of a primary landing site and a backup. The final two sites, along with their operational challenges and scientific expectations, will be presented during the briefing on September 15.
The landing itself is currently scheduled for November 11. This will mark the first time a landing on a comet has ever been attempted. Philae will drill into the surface, extract and analyze samples, and send pictures and data back to Earth.
Rosetta’s rendezvous with Comet 67P/Churyumov-Gerasimenko has opened a new chapter in Solar System exploration. Comets are time capsules containing primitive material left over from the epoch when the Sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission should become the key to unlocking the history and evolution of our Solar System, as well as answering questions regarding the origin of Earth’s water and perhaps even life.
The comet is on a 6.5-year orbit around the Sun and today is 522 million km from it. At their closest approach on 13 August 2015, just under a year from now, the comet and Rosetta will be 185 million km from the Sun, meaning an eightfold increase in the light received from the Sun.
While Rosetta and its scientific instruments will watch how the comet evolves as heating by the Sun increases, observing how its coma develops and how the surface changes over time, the lander Philae and its instruments will be tasked with making complementary in situ measurements at the comet’s surface. The lander and orbiter will also work together using the CONSERT experiment to send and detect radio waves through the comet’s interior, in order to characterise its internal structure.
The orbiter’s payload includes the Alice ultraviolet spectrograph developed by the Southwest Research Institute (SwRI) in Boulder. Alice will analyze gases in the comet’s coma, which is the bright envelope of gas around the nucleus of the comet, and developed as a comet approaches the sun. Alice will also measure the rate at which the comet produces water, carbon monoxide and carbon dioxide. These measurements will provide valuable information about the surface composition of the nucleus.
Rosetta is an ESA mission with contributions from its Member States and NASA. Rosetta’s Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI. Rosetta will be the first mission in history to rendezvous with a comet, escort it as it orbits the Sun, and deploy a lander.