Thursday, February 8, 2007

Rosetta's Swing Lessons

Rosetta, ESA’s comet chaser, is getting closer and closer to it’s Mars swing-by.

As it can be understood from the latest news, everything is working as predicted and a recently revealed wonderful image gives us a good hint about what is on the way.
The Red Planet will be reached on the 25th of the current month, as the spacecraft needs to gain acceleration in order to head towards Mother Earth for the next gravity assist manoeuvre in the month of November.
Taking advantage of this, a series of scientific operations are scheduled for the event.

Dr. Gerhard Schwehm, ESA-ESTEC Head of Solar System Science Operations Division and the mission’s Project Scientist, answers spacEurope questions and give us a full insight on what we will witness in the upcoming days.

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What new informations about Mars can Rosetta, in the whole of it's swing-by adventure, provide us as a must comparing with other missions actually orbiting and roving Mars?

-You have to understand that the gravity assist is for navigation not science. It is a great opportunity to cross calibrate instruments.
We will have the first close UV observation by ALICE, might see the dust environment due to the unique dynamic range and the filters of the OSIRIS camera, and make studies of the atmospheric loss processes by the RPC Plasma package.

From the orbiter which instruments will be used on the Mars swing-by?
And from the Philae Lander instruments? Some work on amino acids detection?

-OSIRIS ( Imaging), Navigation Camera, ALICE (UV Spectrometer), VIRTIS (Visual and IR Mapping Spectrometer), RPC and the cameras on the Lander and ROMAP, the plasma instrument and Magnetometer on the Lander + the Standard Radiation Monitor.
For the amino acids you have to sample and put material in furnace and than run through mass spectrometer. This you can only do when landed. I.e. COSAC will definitely not be on.
From the Lander only the CIVA imaging system and ROMAP will be on. And the Lander instruments can run through closest approach as the Lander has it own power system running on batteries.

Speaking of OSIRIS, what can we expect when compared with other imaging instruments already on Mars?

-Unfortunately we will go through an eclipse at closest approach and have to switch off, otherwise we would have got 4 m resolution as best of MEX HSRC.

And we will observe Phobos.

Phobos and Deimos also. What are the science objectives for Martian moons?

-Add to the data set in imaging and IR mapping: surface composition and morphology.

Trajectory's corrections are planned to the 9 th and the 18 th of February, are preparations following as expected?

-We still have four slots reserved before closest approach. We are very confident that we will only need the slot on 9 Feb. We are already close to the nominal trajectory, presently aim at about 286 km miss distance and as you know the nominal flyby will be at 250km on 25 Feb at 01:58 UTC.

There was a flight-test on the 7 th of January, did it surprise anyway? Were the science operations determinded to be cancelled and give full priority to spacecraft operations?

-I believe you mixing up some info. We had a very intense active payload check out from mid-November for one month where we checked all instruments and in case upgraded the on board S/W. We still have been planning small checks for some of the instruments, but now running the sequences as uploaded and concentrate on the flyby. If we would require a very late orbit update, i.e. a couple of hours before closest approach we would even cancel payload ops. You see: navigation has highest priority.

What can we earn from knowing better the relation between the martian atmosphere and solar wind? And from the radiation environment study?

-We will learn a lot of atmospheric loss processes due to the solar wind penetrating into the atmosphere. Wonderful results from ASPERA on MEX and VEX. We can learn a lot how an atmosphere is evolving through this cleaning process.
SREM provides the radiation environment at Mars and on the way to Mars, which is important for planning future human exploration.

Rosetta will be, at it's closest approach, only 250kms from Mars, which regions of the planet will be surveyed in detail?

-It is more the global aspect as we are switched off at closest approach.

This is a fenomenal mission in all it's extension.
From the Mars observations what results could outcome as a major surprise?

-Detection of dust in the Mars vicinity by OSIRIS would be exciting. we will get anyhow the first UV spectra. And last but not least new info on the plasma environment, the team is already really excited.

But again, do not forget, science here isn't the highest priority we take the opportunity to do science.


For detailed information regarding Rosetta's Mars Swing-by, please consult the Trajectory Status Presentation given by Trevor Morley from the ESOC Flight Dynamics Team for the Mars Swing-by Preparation Readiness Meeting that took place on the February the 2nd and which was kindly made accessible to spacEurope by Dr. Gerhard Schwehm.

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