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No. 228 – Start of eclipse season

No. 228 – Start of eclipse season

Report for the period 7 November to 4 December 2010 (week 45 - week 48)The reporting period, covering four weeks of Venus Express mission operations, was devoted to routine science activities.

An eclipse season started on 18 November 2010; during eclipse seasons, Venus Express passes through the shadow of Venus during part of its orbit around the planet and the resulting additional thermal control and power supply requirements lead to increased demands on the spacecraft’s batteries.

Summary of main activities
During the reporting period, routine mission operations were conducted using the ESA Cebreros ground station (CEB). Delta differential one-way ranging (DDOR) was performed on 12 November 2010, with the telemetry rate set to 22 kilobits per second. Tracking passes were performed on 15 November and 1 December 2010 using the Perth ground station. The beginning of transmission for a number of Cebreros communications passes was delayed at the request of the Venus Express Science Operations Centre (VSOC).

Main activities during reporting period

MET
(Day)

Date
(DD-MON-YYYY)

DOY

Main Activity

MET = Mission elapsed time; DOY = Day of year

1825 7-Nov-2010 311 CEB communications pass.
1826 8-Nov-2010 312 CEB communications pass.
1827 9-Nov-2010 313 CEB communications pass.
1828 10-Nov-2010 314 Short CEB communications pass due to maintenance.
1829 11-Nov-2010 315 Short CEB communications pass due to maintenance.
1830 12-Nov-2010 316 DDOR. CEB communications pass.
1831 13-Nov-2010 317 Telemetry rate set to 182 Kbps.
CEB communications pass.
1832 14-Nov-2010 318 CEB communications pass.
1833 15-Nov-2010 319 CEB communications pass. Perth tracking pass
1834 16-Nov-2010 320 CEB communications pass. Later BOT on VSOC request.
1835 17-Nov-2010 321 CEB communications pass due to maintenance.
1836 18-Nov-2010 322 CEB communications pass due to maintenance. Later BOT at VSOC request. Eclipse season start.
1837 19-Nov-2010 323 CEB communications pass.
1838 20-Nov-2010 324 CEB communications pass.
1839 21-Nov-2010 325 CEB communications pass. Telemetry bit rate decreased to 152kbps.
1840 22-Nov-2010 326 CEB communications pass. Later BOT at VSOC request.
1841 23-Nov-2010 327 CEB communications pass.
1842 24-Nov-2010 328 CEB communications pass. Later BOT at VSOC request.
1843 25-Nov-2010 329 CEB communications pass.
1844 26-Nov-2010 330 CEB communications pass. Later BOT at VSOC request.
1845 27-Nov-2010 331 CEB communications pass. Telemetry bit rate decreased to 114 kbps.
1846 28-Nov-2010 332 CEB communications pass. Later BOT at VSOC request.
1847 29-Nov-2010 333 CEB communications pass.
1848 30-Nov-2010 334 CEB communications pass. Later BOT at VSOC request.
1849 1-Dec-2010 335 CEB communications pass. Perth tracking pass.
1850 2-Dec-2010 336 CEB communications pass. Later BOT at VSOC request.
1851 3-Dec-2010 337 CEB communications pass.
1852 4-Dec-2010 338 CEB communications pass. Later BOT at VSOC request.

At the end of the reporting period on 4 December 2010, Venus Express was at 62.55 million kilometres from Earth. The one-way signal travel time was 208.5 seconds.

At the end of the reporting period, the final oxidizer mass was estimated to be 34.956 kilograms, and the final fuel mass estimate was 21.831 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

An outbound quadrature phase will start later in December 2010, during the next reporting period. 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 nine weeks before an inferior conjunction [see note 2] of Venus and an outbound quadrature phase starting nine weeks after an inferior conjunction. This outbound quadrature phase will start nine weeks after the inferior conjunction that occurred on 30 October 2010.

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 #261 through MOR #264. 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 18:39 UT

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