Relative position of Rosetta and Steins in target plane - 11 August 2008
This plot shows the situation in the target plane for the Rosetta fly-by of asteroid Steins. It is based on the optical navigation data as well as all radiometric data (spacecraft tracking) and ground-based astrometric data up to and including 11 August 2008.
Ellipses indicate 3-sigma error circles around Rosetta's determined positions (crosses) relative to asteroid Steins (red point at origin). The target relative position of Rosetta for the Steins fly-by is marked in green and is 800 km from asteroid Steins.
The plot shows four colour-coded positions, each derived with progressively more input from the optical navigation campaign with Rosetta's on-board cameras.
|The black cross and associated dashed 3-sigma error ellipse is the solution without optical data from the navigation campaign
|The orange cross and associated dashed 3-sigma error ellipse is the solution with additionally the NAVCAM data from 4 August.
|The magenta cross and associated dashed 3-sigma error ellipse is the solution with additionally the optical data from 7 August.
|The blue cross and associated 3-sigma error ellipse is the solution from 11 August.
On 11 August, Rosetta's final projected relative position was 246.4 km from the target and too close to Steins. If there would be no further change to Rosetta's trajectory, the spacecraft would pass asteroid Steins at about 554.2 km (blue cross). A trajectory control manoeuvre (TCM) was performed on 14 August to have the projected postion of Rosetta move close to the target (see related image).