Rosetta flyby of Asteroid Steins, 5th September 2008 Options

[peter59]

Only 78 days to Stein encounter ! I can't believe I forgot about this event.

[cndwrld]

Here is some information on the flyby. I tried to include the timeline, but I'm not familiar with the BB code so I don't know if it will show up. The timeline is in Word table format, and I couldn't figure out how to show it. So I just created a JPG of it and tried to attach it.


Fly-by operations

Rosetta will be closest to Steins on 5 September 2008 at 20:58 CEST (= 18:58 UT, ground time). The minimum distance from the asteroid will be 800 km. This is the minimum distance from which Rosetta is able to track the asteroid continuously.

Rosetta will pass by Steins very fast, at a speed of 8.6 km/s relative to the asteroid. This means that the distance between Rosetta and the asteroid will change very rapidly (by a factor of 10 within 15 minutes before and after the fly-by), and the asteroid will quickly diminish in the cameras’ field of view.

Between 40 and 20 minutes before closest approach, Rosetta will be flipped and readied to enter the asteroid fly-by mode (AFM). During this mode, the orientation of the spacecraft is automatically driven by the navigation cameras to continuously keep the asteroid in the field of view of the imaging instruments.

Although most scientific observations will be performed in the few hours around closest approach, several instruments will be on for a few days around closest approach.

Communication with Earth will take place through ESA’s New Norcia Deep Space antenna as the main station. NASA’s DSN Goldstone, Canberra and Madrid stations will provide support for tracking before closest approach and for science operations, filling the gap in visibility between Cebreros and New Norcia after closest approach. ESA’s Cebreros Deep Space antenna will be used in the 2 days preceding closest approach. Radio signals to and from Rosetta (located at 2.41 Astronomical Units, or about 360 million km from Earth at the time of fly-by) will take 20 minutes to travel to their destination.

A timeline of the main fly-by operations is given below:

CA = Closest Approach;
TCM = Trajectory Correction Manoeuvre;
AFM = Asteroid Fly-By Mode
HGA = High Gain Antenna
Spacecraft time = UT ground time – 20’



There will be material released in the run-up to the flyby, including video- and pod-casts and a web blog. Media activities start at ESOC, Darmstadt at 18:00 CET on Friday, 05 Sept. On Saturday, 06 Sept from 12:00 - 13:00 CET, the results of the flyby will be presented at ESOC and placed on the web pages.