No. 228 – Start of eclipse season
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 |
Date |
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
- The synodic period is the time between two successive identical configurations as seen from the Earth.
- 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.