Asteroid (2867) Šteins Flyby Coming

Rosetta spacecraft meets asteroid Steins
Image credit: ESA TV - Rosetta spacecraft meets asteroid Steins

Rosetta, the European Space Agency (ESA) spacecraft on its way to orbit and deploy a lander on a comet, is now approaching Asteroid (2867) Šteins. The flyby will bring the spacecraft within 800 km of Šteins on Friday evening, September 5, 2008. The ESA will provide a webcast about the event beginning on September 06, 2008 from 04:00 until 11:20 GMT on the Rosetta website. Data is expect on Saturday after the flyby has been completed.

Šteins is 4.6 km in diameter and located in the main asteroid belt. Rosetta will collect information about the asteroid as it speeds by on its way to Comet 67P/Churyumov-Gerasimenko.

Here is the Šteins flyby timeline provided by ESA on the Rosetta Blog:

Timeline of nominal fly-by events

(All event times stated in ground time, CEST)

1 September

02:20 Instruments switched on (except OSIRIS which was already on for the navigation campaign)

4 September

07:20-11:20 Slot for possible trajectory correction manoeuvre (36 hours before closest approach)

13:20-18:20 Last opportunity to acquire images for optical navigation campaign

5 September

07:20-10:20 Slot for possible trajectory correction manoeuvre (12 hours before closest approach)

10:20 Navigation cameras switch to tracking mode – initially both used, then use CAM ‘A’ only (to be decided)

11:00 Uplink fly-by commands for asteroid fly-by mode (AFM)

Includes an update to the command profile already on board & the final updated AFM commands

20:18-20:38 Spacecraft ‘flip over’

20:39 Spacecraft switches automatically to asteroid fly-by mode

20:48 High-gain antenna on hold

From 10 minutes before to about 1 hour after closest approach, the high-gain antenna will not point to Earth. No telemetry will be received until the spacecraft exits the asteroid fly-by mode.

20:56 Sun illuminates Rosetta from the back and the asteroid fully

20:58 Closest approach, at a planned distance of 800 km from the asteroid

21:58 Rosetta automatically exits asteroid fly-by mode, high-gain antenna rotated to Earth pointing (until 22:05)

22:27 First post-fly-by acquisition of signal (AOS) – telemetry received via NASA’s Goldstone ground station

22:30 Start of science data download via Goldstone

6 September

04:06-16:01 Ground station pass via ESA’s New Norcia station – science data download continues. During the first 5 hrs, OSIRIS data will be downloaded, followed by 3:30 hrs of VIRTIS only, and then the rest of the science data

12:00 Live streaming of Rosetta Steins fly-by press conference from ESOC begins

13:00 Images from fly-by published on ESA web

15:00 End of press conference streaming

16:01 End of reception of first set of science data

After 6 September

Daily ground station passes until 5 October, including 8 hrs via New Norcia & one 4-hr DSN pass daily until 14 September – then daily passes via New Norcia only until 5 October.

As soon as the first closeup images of Steins are returned, I will update this page to change the background to a specific Steins theme. Please visit Frontier Channel on Saturday for the latest updates on the flyby.

More Information

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Richard Leis

Richard Leis is a writer and poet living in Tucson, Arizona. His poetry has been published in Impossible Archetype. His essays about fairy tales and technology have been published on Tiny Donkey and Fairy Tale Review’s “Fairy-Tale Files“.