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No. 229 - Start of outbound quadrature phase

No. 229 - Start of outbound quadrature phase

Report for the period 5 December 2010 to 1 January 2011 (week 49 - week 52)The reporting period, covering four weeks of Venus Express mission operations, was devoted to routine science activities.

An outbound quadrature phase began on 30 December 2010. Quadrature phases are periods of about five weeks during which the Sun-spacecraft-Earth angle is between 75° and 95°. They occur twice in every synodic period [see note 1] of Venus (584 days, or about 19 months), with an inbound quadrature phase ending 9 weeks before an inferior conjunction [see note 2] of Venus and an outbound quadrature phase starting 9 weeks after an inferior conjunction. This outbound quadrature phase started nine weeks after the inferior conjunction that occurred on 30 October 2010.

Summary of main activities
During the reporting period, routine mission operations were conducted using the ESA Cebreros ground station (CEB). The beginning of transmission for a number of Cebreros communications passes was delayed at the request of the Venus Express Science Operations Centre (VSOC). The delayed start of the communication passes allowed the Venus Monitoring Camera (VMC) team to take images with optimal angles to track cloud movements. A number of Cebreros communications passes were shortened, either at the request of VSOC or due to scheduled maintenance of the ground station. Delta differential one-way ranging (DDOR) was performed on 7 December 2010. A tracking test was performed using the Perth ground station (PER) on 9 December 2010. An orbital correction manoeuvre (OCM) was performed on 12 December 2010.

Main activities during reporting period

MET
(Day)

Date
(DD-MON-YYYY)

DOY

Main Activity

MET = Mission elapsed time; DOY = Day of year

1853 5-Dec-2010 339 CEB communications pass.
1854 6-Dec-2010 340 CEB communications pass. Later BOT at VSOC request. Telemetry bit rate set to 91 kbps before CEB pass.
1855 7-Dec-2010 341 CEB communications pass. DDOR before communications pass.
1856 8-Dec-2010 342 CEB communications pass. Later BOT at VSOC request.
1857 9-Dec-2010 343 CEB communications pass. PER tracking test before communications pass.
1858 10-Dec-2010 344 CEB communications pass. Later BOT at VSOC request.
1859 11-Dec-2010 345 CEB communications pass.
1860 12-Dec-2010 346 CEB communications pass. OCM performed.
1861 13-Dec-2010 347 CEB communications pass. Telemetry bit rate set to 76 kbps before CEB pass.
1862 14-Dec-2010 348 CEB communications pass. Shortened due to CEB maintenance.
1863 15-Dec-2010 349 CEB communications pass. Shortened due to CEB maintenance.
1864 16-Dec-2010 350 CEB communications pass.
1865 17-Dec-2010 351 CEB communications pass.
1866 18-Dec-2010 352 CEB communications pass.
1867 19-Dec-2010 353 CEB communications pass. Telemetry bit rate set to 57 kbps before CEB pass.
1868 20-Dec-2010 354 CEB communications pass.
1869 21-Dec-2010 355 CEB communications pass.
1870 22-Dec-2010 356 CEB communications pass.
1871 23-Dec-2010 357 CEB communications pass.
1872 24-Dec-2010 358 CEB communications pass.
1873 25-Dec-2010 359 CEB communications pass.
1874 26-Dec-2010 360 CEB communications pass.
1875 27-Dec-2010 361 CEB communications pass.
1876 28-Dec-2010 362 CEB communications pass.
1877 29-Dec-2010 363 CEB communications pass.
1878 30-Dec-2010 364 CEB communications pass. Telemetry bit rate set to 45 kbps before CEB pass. Quadrature entry. Shortened pass at VSOC request.
1879 31-Dec-2010 365 CEB communications pass.
1880 1-Jan-2011 1 CEB communications pass.

At the end of the reporting period on 1 January 2011, Venus Express was at 93 million kilometres from Earth. The one-way signal travel time was 310 seconds.

At the end of the reporting period, the final oxidizer mass was estimated to be 34.732 kilograms, and the final fuel mass estimate was 21.687 kilograms.

Payload Activities

ASPERA The instrument was regularly operated as part of the routine plan.
MAG The instrument was regularly operated as part of the routine plan.
PFS The instrument was not operated.
SPICAV The instrument was regularly operated as part of the routine plan.
VMC The instrument was regularly operated as part of the routine plan.
VeRa No operations.
VIRTIS The instrument was regularly operated as part of the routine plan.

Future Milestones

The swap from using the small high-gain antenna (HGA2) for Earth communications to HGA1 will be performed on 12 January 2011. Earth occultation season #10 will start on 17 January 2011. The spacecraft will exit outbound quadrature on 6 February 2011.

Occultation #10 will start in January 2011.

Notes

  1. The synodic period is the time between two successive identical configurations as seen from the Earth.
  2. A conjunction is the alignment of two Solar System bodies (in this case Venus and the Sun) so that they have the same longitude as seen from Earth. An inferior conjunction occurs when Venus is between the Sun and the Earth; superior conjunction refers to when Venus is on the opposite side of the Sun from Earth.


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Legal disclaimer
This report is based on four ESOC mission operations reports, MOR #265 through MOR #268. Please see the copyright section of the legal disclaimer (bottom of this page) for terms of use.

Last Update: 1 September 2019
30-Nov-2021 17:35 UT

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