ESA Venus Express Status Report No. 82 – MESSENGER Flyby

14 Jun 2007 16:26

Report for Period 3 May to 9 June 2007

This period saw Venus Express’s special operations during the flyby of Venus by NASA’s MESSENGER spacecraft. Two full Cebreros passes were skipped to allow for the observations which proceeded as planned. One additional Cebreros pass was shortened to 3 hours to allow for proper cooling of VIRTIS prior to the observations.

The table below shows a chronology of the main activities in the reporting period:

At the end of the last Cebreros pass in the reporting period (DOY 160, 18:00z) Venus Express was orbiting Venus at 105 million km from the Earth. The one-way signal travel time was 352 seconds.

MESSENGER Flyby

Closest approach to Venus occurred at 23:08 UT on 5 June, with the MESSENGER spacecraft flying within 338 km over the Venusian coordinates 12.25° South and 165° East. At the time, Venus Express was on the opposite side of Venus, but it passed over the same region as MESSENGER both several hours before and after the flyby (orbital period of 24 hours). Together, the two spacecraft carried out observations of Venus’s cloud deck, plasma environment, atmosphere and its oxygen airglow and surface.

The flyby observations were further joined by ground based telescopes around the world in a coordinated campaign. For more details see also “Coordinated Ground-based Observation Campaign” in the right hand side navigation. 

Payload Activities

ASPERA
ASPERA has been reporting thermal out-of-limit (OOL) conditions at switch-on, when activated during Earth communications phases. Further instances of OOLs at switch-on have been avoided by disabling ASPERA mission timeline telecommands during periods of Earth pointing.