Rosetta - Europe's comet chaser
Philae landing on cometArtist’s impression of the Rosetta orbiter deploying the Philae lander to comet 67P/Churyumov–Gerasimenko (not to scale).
Gas and dust streams from the ‘neck’ of Comet 67P/ Churyumov-GerasimenkoSince its arrival at the comet, Rosetta has observed jets of gas and dust. Numerous gas eruptions have been observed originating from the ‘neck’ of the comet. Using the measurements performed by the VIRTIS spectrometer, it has been possible to recognise a day/night cycle of cometary activity and identify the mechanism responsible.
Rosetta's journey through the Solar System (Click on the picture to see in larger scale); (c) DLR CC-BY 3.0To reach its destination adapting its route to match the comet's trajectory and substantial changes in speed were necessary. In practical terms, the orbiter accelerated by building momentum as it passed by Earth or Mars on what is known as a swing-by manoeuvre.
From time to time, the Rosetta orbiter was manoeuvred to within two kilometres of the comet in preparation for the end of the mission.On these occasions the OSIRIS camera managed to acquire images showing details just a few centimetres across. The surprise came on 2 September 2016: Philae was found in the shadows of a rock formation, lying sideways.
The European Space Agency (ESA) Rosetta mission was designed to study the formation and evolution of the Solar System by exploring one of the oldest and most primordial heavenly bodies – comets. The mission consisted of the Rosetta orbiter and the Philae lander. The probes were launched on 2 March 2004, travelled 6.4 billion kilometres in 10 years and, with the help of a few planet swing-bys, arrived at Comet 67P/Churyumov-Gerasimenko on 6 August 2014.
DLR played a major role in the construction of the lander and operated the Lander Control Center (LCC), from where the difficult task of landing on the comet on 12 November 2014 – a feat never before accomplished – was designed and controlled. On 27 July 2016, after almost two years of cometary exploration, the communications unit on board the Rosetta orbiter (which it used to communicate with the Philae lander) was switched off. On 30 September 2016, the operational part of the mission came to an official end, with the orbiter's controlled descent.
Rosetta at a glance - technical data and timeline
|The European Space Agency (ESA) approves the Rosetta mission:||November 1993|
|Original launch date:|
(to comet 46P/Wirtanen;
postponed due to technical problems
with the launcher)
|Beginning of 2003|
|Launch of Rosetta to comet 67P/Churyumov-Gerasimenko:||02 March 2004, 08:17 CET|
|1st Earth gravity assist:||04 March 2005|
|Mars gravity assist:||25 February 2007|
|2nd Earth gravity assist:||13 November 2007|
|Asteroid Steins flyby:||05 September 2008|
|3rd Earth gravity assist:||13. November 2009|
|Asteroid Lutetia flyby:||10 July 2010|
|Enter deep space hibernation:||08 June 2011|
|Exit deep space hibernation:||20 January 2014, 10:00 GMT|
|Major comet rendezvous manoeuvre:||May 2014|
|Arrive at comet:||06 August 2014|
|Philae lander delivery:||12 November 2014|
(Closest approach to Sun):
|13 August 2015|
|Mission end:||30 September 2016|
|Launch date:||2 March 2004, 08:17 CET|
|Launch site:||Kourou, French Guiana|
|Launcher:||Ariane 5 G|
|Mission duration:||12 years in total, until December 2015|
|Mission Control Centre:||European Space Operations Center (ESOC), Darmstadt|
|Philae Lander Control Centre:||DLR Microgravity User Support Centre, Cologne|
|Ground stations:||Perth, Australia and Kourou, French Guiana|
|Launch mass:||3000 kilograms|
|Science payload:||165 kilograms|
|Orbiter dimensions:||2.8 x 2.1 x 2.0 metres|
|Solar panel dimensions:||Two panels, each 14 metres long; total surface area of 64 square metres|
|Power via solar panels:||850 W at 3.4 AU*, 395 W at 5.25 AU*|
(* AU = Astronomical Unit = roughly the distance from Earth to the Sun)
|Communications antenna:||Two-axis steerable high-gain antenna, 2.2 metres in diameter|
|nstruments on the orbiter (11)|
|ALICE:||imaging ultraviolet spectrometer to analyse the composition of the comet's nucleus, coma and ion tail.|
|CONSERT (COmet Nucleus Sounding Experiment by Radio wave Transmission):||transmits long-wave radio signals through the comet's nucleus to explore its structure.|
|COSIMA (COmetary Secondary Ion Mass Spectrometer):||mass spectrometer that collects cometary dust grains and analyses their chemical composition.|
|GIADA (Grain Impact Analyser and Dust Accumulator):||determines the number, size and speed of the dust grains in the coma.|
|MIDAS (Micro-Imaging Dust Analysis System):||high-resolution scanning probe microscope that studies the fine structure of the dust particles around the asteroids and comet.|
|MIRO (Microwave Spectrometer for the Rosetta Orbiter):||microwave instrument for determining the composition of the core and coma, as well as for measuring cometary activity and determining physical properties of the surface of the nucleus (temperature) and coma molecules (density, temperature, and velocity).|
|OSIRIS (Optical, Spectroscopic, and InfraRed Remote Imaging System):||a telephoto and wide-angle camera that will acquire high-resolution images in different spectral bands for the characterisation of the nucleus and its surroundings.|
|ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis):||the instrument consists of two mass spectrometers and a pressure sensor and determines the chemical composition of the coma, the isotope ratios and the temperature and speed of the gas molecules.|
|RPC (Rosetta Plasma Consortium):||comprises ion and electron detectors and a magnetometer to measure physical properties of the nucleus and coma as well as the interaction of the coma and tail with the solar wind.|
|RSI (Radio Science Investigation):||uses the spacecraft communication system to determine the gravitational field, the comet size, mass and shape, as well as the structure of the nucleus.|
|VIRTIS (Visible and Infrared Thermal Imaging Spectrometer):||Abbildendendes Spektrometer, das die Zusammensetzung und Temperatur der Oberfläche misst sowie die Gasmoleküle in der Koma charakterisiert.|
|Data transmission:||16 kilobytes per second via the orbiter|
|Energy supply:||Solar generator, 4 Watts, primary (for the first 60 hours after the landing on the comet) and secondary (rechargeable) batteries|
|Instruments on the lander (10)|
|APX (Alpha-Particle-X-Ray-Spectrometer):||spectrometer for analysing the chemical composition of matter directly on the comet's surface.|
|CIVA (Comet Infrared and Visible Analyzer):||photographs the landing site and examines the samples of the comet’s surface acquired with the SD2 drill through microscopes.|
|CONSERT (Comet Nucleus Sounding Experiment by Radio wave Transmission):||radio wavelength probe for the screening of the nucleus in conjunction with the orbiter.|
|COSAC (Cometary Sampling and Composition):||determines the elementary, isotopic and chemical composition of the frozen components of the comet’s surface to a depth of 30 centimetres.|
|MUPUS (Multi-Purpose Sensors for Surface and Subsurface Science):||several sensors measure the surface temperature and thermal conductivity of the ground.|
|PTOLEMY:||an evolved gas analyser, which obtains accurate measurements of isotopic ratios of light elements.|
|ROLIS (Rosetta Lander Imaging System):||panoramic camera to photograph the landing site during and after Philae's landing phase.|
|ROMAP (Rosetta Lander Magnetometer and Plasmamonitor):||studies the magnetic field of the comet and the comet/solar-wind interaction.|
|SD2 (Sample, Drill and Distribution):||drilling mechanism for obtaining samples at a depth of up to 30 centimetres.|
|SESAME (Surface Electric Sounding and Acoustic Monitoring Experiment):||comprises sensors for measuring the acoustic and dielectric characteristics of the nucleus as well as a particle impact monitor.|
Kuiper Belt object moving in an elliptical orbit around the Sun between Jupiter and
|Year of discovery:||1969|
|Discoverers:||K. Churyumov, University of Kiev, Ukraine|
S. Gerasimenko, Institute of Astrophysics, Dushanbe, Tajikistan.
|First images of comet nucleus:||Acquired on 12 March 2003 by the Hubble Space Telescope; they show an oval body roughly 3 by 5 kilometres.|
|Mean diameter of nucleus:||4 kilometres|
|Orbital period around the Sun:||6.45 years|
|Minimum distance to the Sun (perihelion):||186 million kilometres (1.24 AU* )|
|Maximum distance from the Sun (aphelion):||857 million kilometres (5.68 AU* )|
|Orbital eccentricity:||0.64 (elliptical orbit)|
|Rotation period:||12.4 to 12.9 hours|
|Development of orbit:||In 1840, the perihelion distance was 4 AU; a Jupiter flyby followed, decreasing the perihelion distance. By 1959, the perihelion distance was 2.7 AU; another Jupiter flyby in February 1959 reduced it further to today's value.|
|Albedo (reflectivity):||0.04 (very low, darker than coal).|
|Density of the surface material:||100 to 500 kilograms per cubic metre (comparable with a dry sponge).|
|Mass loss:||During the perihelion pass on 13 August 2015, up to 300 kilograms of comet dust per second were swept to space by sublimating ice.|
* AU = Astronomical Unit = roughly the distance from Earth to the Sun
Rosetta 'post-mission' – new findings relating to the temperature and nature of the comet's surfaceTwo-and-a-half years have passed since the operational phase of the Rosetta mission came to an end in September 2016. However, scientific evaluation of the enormous amounts of data from the instruments on the spacecraft and the Philae lander is still ongoing.
‘Comets – The Rosetta Mission’ Exhibition Curation Team Awarded Europlanet Prize 2017The 2017 Europlanet Prize for Public Engagement with Planetary Science has been awarded to the team behind the outstandingly successful exhibition, ‘Comets – The Rosetta Mission: Journey to the Origins of the Solar System’, at the Museum für Naturkunde, Berlin. Ulrich Köhler, Barbara Stracke and Ekkehard Kührt, of the DLR Institute of Planetary Research, will accept the award on behalf of the exhibition’s curation team.
More than 700,000 visitors at the 'COMETS' exhibitionThe special exhibition 'COMETS – The Rosetta mission: A journey to the origins of the Solar System' has been the main attraction at the Museum für Naturkunde in Berlin for the last six months. Conceived and prepared by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) in cooperation with the world-famous Berlin museum and the Max Planck Society, the exhibition ended on 26 January 2017.
End of mission for RosettaOn 30 September 2016 at 13:19 CEST, the final signal from the Rosetta orbiter was received back on Earth. The ESA mission ended when the spacecraft touched down on Comet 67P/Churyumov-Gerasimenko. The international team of scientists had already said their farewells to the Philae lander back in February 2016, when its prolonged radio silence indicated that it would no longer report back to the team in the control centre at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR).
Company for the Philae landerThe Philae landing craft touched down on comet on 12 November 2014. It has now been found: it is not located at the convenient site originally selected for its landing, but rather – following a series of three bounces – in a grim and dark environment.
Comet lander Philae foundThe comet lander Philae has been found. The OSIRIS camera on board the Rosetta orbiter took the revealing images of the surface of Comet 67P/Churyumov-Gerasimenko on 2 September 2016. They show the landing craft lying sideways in a crevasse. Two of the three landing legs are clearly visible.
A slow farewell – Time to say goodbye to PhilaeThe last prolonged silence had already indicated that contact with the Philae lander will be increasingly unlikely, and the conditions on Comet 67P/Churyumov-Gerasimenko have become more hostile. "Unfortunately, the probability of Philae re-establishing contact with our team at the DLR Lander Control Center (LCC) is almost zero, and we will no longer be sending any commands; it would be very surprising if we received a signal now," said Stephan Ulamec Philae Project Manager of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR).
The Philae lander – three 'feet' on the ground, and all set to goPhilae was more than 500 million kilometres from Earth when it touched down on Comet 67P/Churyumov-Gerasimenko one year ago, on 12 November 2014. "We looked after and planned this mission for almost 20 years and launched the Rosetta orbiter and Philae lander on their journey through space – so landing day really was quite special," says Philae Project Manager Stephan Ulamec from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) to sum up the mood on the day.
Churyumov-Gerasimenko – mystery of the 'rubber duck' shape solvedShaped like a rubber duck – this was the talk upon the discovery of Comet 67P/Churyumov-Gerasimenko's surprising shape in July 2014. Scientists were amazed at the celestial body's extraordinary shape, which was revealed by the European Rosetta spacecraft.
Steam under the hood - an insight into ice patterns on Comet 67P/Churyumov-GerasimenkoGas and dust streams from the ‘neck’ of Comet 67P/ Churyumov-Gerasimenko Since its arrival at the comet, Rosetta has observed jets of gas and dust. Numerous gas eruptions have been observed originating from the ‘neck’ of the comet. Using the measurements performed by the VIRTIS spectrometer, it has been possible to recognise a day/night cycle of cometary activity and identify the mechanism responsible.