OSIRIS
The Scientific Imaging System for Rosetta
Optical, Spectroscopic, and Infrared Remote Imaging System
OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) is the main scientific imaging system on the orbiter of ESA's 
Rosetta mission to comet 67P/Churyumov-Gerasimenko.
OSIRIS comprises a high resolution Narrow Angle Camera (NAC) and a Wide Angle Camera (WAC). The NAC is designed to obtain high resolution images of the surface of comet 67P/Churyumov-Gerasimenko through 12 discrete filters over the wavelength range from 250 to 1000 nm at an angular resolution of 18.6 µrad/px. The WAC is optimised to provide images of the near nucleus environment in 14 discrete filters (240-720 nm) at an angular resolution of 101 µrad/px. Both cameras are equipped with 2048 x 2048 pixel CCD detectors, and have an off-axis optical configuration.
After the launch of Rosetta (2nd March 2004), OSIRIS was commissioned in seven slots between March 2004 and June 2005, and has been and will be actived on several occasions before Rosetta arrives in 2014 at its main target, comet 67P/Churyumov-Gerasimenko. OSIRIS already provided important scientific results. A monitoring campaign of comet 9P/Tempel 1 around the Deep Impact event on 4 July 2005 constitutes the first scientific observations with OSIRIS. The most important scheduled observing opportunities, before the arrival to 67P/Churyumov-Gerasimenko, are the Mars swing-fly-by in Feb. 2007, two Earth swing-bys in Nov. 2007 and Nov. 2009, and the fly-bys of the asteroids Steins (Sep. 2008) and Lutetia (July 2010).
The OSIRIS cameras were provided by a consortium from 5 European countries and from ESA, under the leadership of the the Max-Planck-Institute for Solar System Research (MPS) (Principal Investigator: H.U. Keller).
Science Objectives
The main objetive of OSIRIS is to study the physical and chemical processes that occur in, on, and near the cometary nucleus. In particular, OSIRIS allows researchers to determine the outflow of gas and dust from different regions of the cometary nucleus, and to compare active areas with deviations in surface mineralogy, in topography, and in local insolation. The main science objetives of OSIRIS are:
- characterise the size, shape, and density of the nucleus of comet 67P/Churyumov-Gerasimenko
- determine the rotational properties of the comet
- monitor the nucleus activity over many months at various scales
- study the mineralogy of the nucleus surface
- find a suitable landing spot for Philae, the Rosetta lander
The Instrument
The OSIRIS cameras are unobstructed mirror systems, equipped with two filter wheels containing 8 position each, and with backside illuminated CCD detectors comprising 2048 x 2048 pixels with a pixel size of 13.5 µm. Both cameras use identical image acquisition systems, consisting of the Focal Plane Assembly and the CCD Readout Box. The figure shows the two OSIRIS cameras (top and left) mounted on the -x panel of Rosetta.
OSIRIS comprises two cameras:
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NAC (Narrow Angle Camera)
The Narrow Angle Camera is designed to obtain high-resolution images of the comet at distances from more than 500 000 km down to 1 km, and of the asteroids 2867 Steins and 21 Lutetia during the interplanetary cruise. The camera also should be able to detect small ejected particles close to the cometary nucleus (brightness ratio = 1/1000). The NAC is equipped with 12 filters to characterise the reflectivity spectrum of the nucleus surface over a wide spectral range from 250 to 1000 nm. The NAC has a square field of view (FOV) of width 2.2o, has an instantaneous field of view (IFOV) of 18.6 µ rad (3.8 arcsec) per pixel, and is a moderately fast system (f/8). The system has a 717 mm focal length. A flat-field, three anastigmatic mirror system is adopted. It has a mass of 13.2 kg.
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WAC (Wide Angle Camera)
The principal objective of this camera is to study the intensity of gas emissions and dust-scattered sunlight as functions of position and viewing angle in the vicinity of the nucleus. The WAC is accomplished by 14 filters from 240 to 720 nm. Seven of the narrow band filters isolate gas emissions from the cometary coma; the others filters measure the dust continuum at wavelengths close to that of the gas emissions. The WAC has a FOV of 12x12o , has an angular resolution of 101 µ rad (20.5 arcsec) per pixel, and is a system with a fast focal ratio of f/5.6. The system has a 140 (sag)/131 (tan) mm focal length. Two aspherical mirror system is adopted. It weighs 9.5 kg.
Operations
Since March 2005 instrument health has been monitored in a checkout every 6 months. The instrument proved to be in good health in the two checkouts performed so far. Operations have included mechanism tests, instrument calibration, alignment between the boresights of the different remote sensing instruments on Rosetta, and interference check between OSIRIS and other instruments.
The Team
| Horst Uwe Keller |
OSIRIS Principal Investigator |
+49 5556 979 419 |
 keller@mps.mpg.de |
| Holger Sierks |
Co-Investigator, Manager of the Flight Instrument and Operations |
| Michael Küppers |
Co-Investigator, Science Coordinator |
| Stubbe Hviid |
Co-Investigator, Instrument Operations Manager |
| Rainer Kramm |
Co-Investigator, Detector Engineer |
| Miriam Rengel |
Post-doctoral Research Fellow |
| Wojtek Markiewicz |
Associate Scientist |
| Irene Büttner |
Ground Segment Engineering |
| Oliver Küchemann |
Instrument operations software |
| Sofie Spjuth |
Ph.D. student |
| Peter Barthol |
Co-Investigator -retired- |
| Werner Curdt |
Co-Investigator -retired- |
Related Press Releases
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Max-Planck-Forscher beobachten Auswirkungen des Einschlags auf dem Kometen Tempel 1
Press Release 06/2005 - 5th July 2005
Das Kamerasystem OSIRIS auf der Raumsonde ROSETTA misst dramatischen Helligkeitsanstieg.
Am 04. Juli um 7:52 mitteleuropäischer Sommerzeit schlug ein Kupfer-Projektil in den Kometen Tempel 1 ein, das von der NASA-Raumsonde Deep Impact zuvor abgefeuert wurde.
An der internationalen Kampagne zur Beobachtung der Folgen des Einschlags auf den Kometen nahm auch die ...
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Max-Planck Forscher beobachten Beschuss des Kometen Tempel
Press Release 05/2005 - 27th June 2005
Am 4. Juli 2005, 7:52 Uhr MESZ wird die NASA-Raumsonde "Deep Impact" einen 370 kg schweren Kupferblock mit einer Geschwindigkeit von 37100 km/h auf den Kometen 9P/Tempel 1 schießen.
Die Kollision, die etwa 4.5 Tonnen TNT entspricht, wird von der Raumsonde selbst, aber auch von vielen Stationen auf der Erde, vom Weltraumteleskop Hubble und der Raumsonde Rosetta beobachtet werden.
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ESA-Mission "Rosetta" vor dem Start
Press Release 01/2004 - 10th February 2004
Am 26. Februar 2004 um 4.16 Uhr oder 4.36 Uhr Ortszeit (8.16 Uhr oder 8.36 Uhr Mitteleuropäische Zeit) soll von Kourou in Französisch-Guayana aus die ESA-Mission "Rosetta" zu einer spektakulären Kometenmission starten.
Die Raumsonde besteht aus zwei Teilen - dem Orbiter "Rosetta" und einem integrierten Landegerät, das erst vor wenigen Tagen "Philae" getauft wurde. Beide treten ihren Flug gemeinsam an und sollen sich nach einer ...
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