* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Home -> Astronomy News -> Mission News -> Rosetta mission
Post Info
TOPIC: Rosetta mission
Blobrana


L

Posts: 131433
Date:
RE: Rosetta mission
Permalink  
 

Observational and theoretical studies of Comet 67P/Churyumov-Gerasimenko, the target of ESAs Rosetta mission, are building a detailed portrait of the comets nucleus as it travels around the Sun.
Observations of the comet using the 8.2 m-ESO Very Large Telescope (VLT) show an irregularly-shaped object that is about 4.6 kilometres in diameter with a rotational period of 12 hours 49 minutes.

 These observations were taken when the comet was approaching the furthest point from the Sun in its orbit. Rosetta will rendezvous with the comet in 2014 at a distance of about 600 million kilometres from the Sun. While a quite detailed portrait of the comet at small heliocentric distance has been drawn, a profound description of Rosettas target comet at large heliocentric distance is missing - Ms Cecilia Tubiana, who will be presenting results at the second European Planetary Science Congress (EPSC) in Potsdam on Tuesday 21st August.

A team of scientists, led by the Max Planck Institute for Solar System Research, observed the comets nucleus in June 2004, May and August 2006 and July 2007, when the comet was at least 680 million kilometres from the Sun.
Surprisingly, although the comet was not active, they found that a faint dust trail is visible in the images of the comet, extending more than 500 000 km along the comets orbital path.

 We believe that this dust trail is composed of large grains that the comet shed over the many times it has travelled along this path - Ms Cecilia Tubiana

Later on Tuesday 21st at the EPSC, Dr Jérémie Lasue, of the Service daéronomie in France, will present results of numerical studies that describe how a comets nucleus changes as it travels along its orbital path.

 Comets constantly evolve by ejecting material as their distance from the Sun changes and their temperature increases or falls. To land on a comets nucleus, you need to have a good idea of its structure, density and tensile strength. Comet 67P/Churyumov-Gerasimenko most probably has an irregular comet nucleus with crater-like depressions on its surface. Our team has developed a three-dimensional model of the internal processes in the nucleus, allowing us to predict the thermal evolution and surface activity as the comet moves along its orbit - Dr Jérémie Lasue.

Recent mission results suggest that a comets structure is highly stratified.

 Stardust showed that the dust ejected from the outer layers is composed of fluffy particles that can be relatively large.  These particles are rich in silicates and organics, which are the building blocks of life. Our simulations, for the first time, take into account the relationship between the impact history of the comet and the forces holding the comets constituents together. This technique has enabled us to reproduce and interpret the amazing layered structure and surface features that Deep Impact observed at comet 9P/Tempel 1. This is a new means to quantify the tensile strength of comet nuclei, which gives us vital information in preparing for Rosettas rendezvous with 67P/Churyumov-Gerasimenko - Dr Jérémie Lasue.

The teams of scientists from France and Italy in which Dr Lasue works, are developing these numerical tools to support two of Rosettas instruments:
VIRTIS, which will determine the composition of the ices in the comets nucleus as well as emitted gases and dust, and CONSERT, which will investigate the deep interior of the nucleus with radio waves.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

ESAs Rosetta and NASAs New Horizons are working together in their joint campaign to observe Jupiter. A preliminary analysis of the data from Rosettas Alice ultraviolet spectrometer indicates that the data quality is excellent and that good science is expected to follow.
New Horizons made its closest approach to Jupiter on 28 February 2007. Its principal objective was to use the gravity of the giant planet to slingshot it onwards to its rendezvous with Pluto, planned for 2015.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

During the very first observations of Rosetta’s flyby target 2867-Steins in March 2006 the onboard camera OSIRIS obtained the most accurate ‘light curve’ of this asteroid so far.
 OSIRIS observed Steins from a distance of 159 million kilometres and, from there, it obtained images and important clues about its characteristics.
Although ESA’s Rosetta is still far away from its destination comet 67P/Churyumov-Gerasimenko and its flyby targets 2867-Steins and 21-Lutetia, scientists have already started to collect preliminary data about these two largely unexplored asteroids. Advanced knowledge of the asteroids’ properties (like size and rotation period) is essential for the preparation of the planned asteroid observation campaigns in September 2008 and July 2010, respectively.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

ESA and NASA are mounting a joint campaign to observe Jupiter over the next few weeks with two different spacecraft. Rosetta will watch the big picture from its current position near Mars, whilst New Horizons will take close-up data as it speeds past the largest planet in our Solar System on its journey to Pluto.
 The co-ordinated observational campaign of Jupiter using Rosetta and New Horizons began this week. Jupiter remains a fascinating world of scientific mystery.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

During Rosetta's recent Mars swingby, the OSIRIS cameras captured a series of images of Mars and of Phobos transiting Mars' disk. The OSIRIS team have produced a cool animated sequence and a 3D view of the Red Planet.
The animated sequences (one faster, one slower) show the shadow of Phobos transiting Mars' disk on 24 February; the images were captured around 22:08 CET, a few hours prior to Rosetta's successful Mars swingby on 25 February.
The movies were produced by combining a series of separate images taken by the Optical, Spectroscopic and Infrared Remote Imaging System (OSIRIS) on board Rosetta.
The background of Mars changes slightly from image to image since the individual images were acquired using different colour filters. Phobos appears dark because it reflects less sunlight than Mars.

rosetta.phobos
Expand (22kb, 560 x 420)

Phobos is the inner moon of Mars; Phobos orbits closer to a major planet compared to any other moon in our solar system (less than 6000 km above the surface of Mars), and it is also one of the smallest known moons in the solar system.

MarsNACColorCloud
Expand (74kb, 1024 x 768)
Credits: ESA © 2007 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

At closest approach at 03:15 CET on 25 February, Rosetta passed over the planet's surface at a relative speed of 36 191 km/hr. During the swingby, the gravitational energy of Mars helped Rosetta change direction, while the spacecraft was decelerated with respect to the Sun by an estimated 7887 km/hour.
During the swingby, the gravitational energy of Mars helped Rosetta change direction, while the spacecraft was decelerated with respect to the Sun by an estimated 7887 km/hour. The spacecraft is now on the correct track towards Earth - its next destination planet whose gravitational energy Rosetta will exploit in November this year to gain acceleration and continue on its trek.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

This stunning view, showing portions of the Rosetta spacecraft with Mars in the background, was taken by the Rosetta Lander Imaging System (CIVA) on board Rosetta’s Philae lander just four minutes before the spacecraft reached closest approach to the Red Planet earlier this morning.

CIVA_Mars
Expand (257kb, 1024 x 1024)
Credits: CIVA / Philae / ESA Rosetta

While the Rosetta orbiter instruments were switched off as planned during several hours around closest approach, which occurred at 03:15 CET today, some of the lander instruments were operational and collected data from Mars.
This incredible CIVA image was taken about 1000 kilometres from the planet’s surface. A portion of the spacecraft and one of its solar arrays are visible in nice detail. Beneath, an area close to the Syrtis region is visible on the planet’s disk.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Two-colour composite of Mars seen by the OSIRIS narrow-angle camera on 24 February at 19:28 CET from a distance of about 240 000 km. Image resolution is about 5 km. The greenish regions are clouds above the red surface of Mars.

rosettaMars
Expand (57kb, 1024 x 768)
Expand (1234kb, 2048 x 2048)
Credits: ESA © 2007 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

A European space probe has completed a close fly-by of the planet Mars in a crucial manoeuvre on its 10-year journey to land on a distant comet.
The unmanned Rosetta craft passed within some 250 km of Mars.
In a precise move, the probe used the planet's gravity to change course on its voyage to the Churyumov-Gerasimenko comet out near Jupiter.

Read more

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

The timeline for Rosetta's speedy swingby of Mars on 25 February includes a series of slew manoeuvres, an occultation and signal blackout, an eclipse and some excellent opportunities for scientific observations.
 Rosetta's Mars swingby kicks off today with a series of complex slew manoeuvres to enable instrument calibration. The spacecraft has been correctly lined up on the proper trajectory since a series of engine firings in the past several weeks.
Rosetta is expected to pass the Red Planet at 250 km altitude and 36 191 km/hour with respect to Mars at closest approach. The swingby should reduce Rosetta's velocity with respect to the Sun by 7887 km/hour, and the spacecraft should depart Mars travelling at 78 779 km/hour relative to the Sun.

Timeline of major activities
 Note: Times shown are ground event times in Central European Time, equivalent to UTC (Coordinated Universal Time) + 1 hour. Spacecraft event time is 17 mins 33 secs earlier.
 
23 February
 17:32    First of a series of slew manoeuvres to perform instrument calibrations
19:30    Flight Control Team in ESOC's Main Control Room (MCR) around the clock

24 February
~14:00    Webcam in MCR switched on (access via ESA portal)
18:35    Additional slew manoeuvres to perform Mars observations with onboard instruments
22:30    End of observations until after Mars swingby

Source

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

On Sunday 25 February, ESA’s probe Rosetta, currently on a ten-year journey to comet Churyumov-Gerasimenko, will make its closest approach to the planet Mars, coming within 250 kilometres of its surface.
The critical close swingby of Mars is needed to use the gravity of Mars to modify the spacecraft’s speed and direction. Rosetta will emerge from its martian encounter pointed towards its next target, Earth ! It arrives for a second swingby of our home planet on 13 November (the first having already taken place on 4 March 2005).

Read more

__________________
«First  <  1 … 14 15 16 17 18  >  Last»  | Page of 18  sorted by
Quick Reply

Please log in to post quick replies.
Home -> Astronomy News -> Mission News -> Rosetta mission


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard