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Planetary News: Venus Express (2006)

Europe Prepares for Venus Express' Arrival

By Emily Lakdawalla
April 3, 2006
Venus Express
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Venus Express
Credit: ESA

On April 11, 2006 at 07:17 UTC (00:17 PDT), the European Space Agency's Venus Express will fire its engines to enter orbit at Venus. Venus Express will be the first spacecraft in orbit at the planet since NASA's Magellan returned its last signal to Earth on October 12, 1994.

Venus Express is the last in a series of three ESA spacecraft that were based on the same spacecraft design. The first, Rosetta, launched March 2, 2004, with a price tag of more than 1 billion Euros. The second, Mars Express, reused the Rosetta design and a few of the instruments and was launched June 2, 2003 at a cost of 300 million Euros. Venus Express, launched November 9, 2005, reuses the design again and has instruments with heritage from both Mars Express and Rosetta at a cost of 220 million Euros.

The science objectives of the instrument suite on Venus Express focus primarily on understanding Venus' thick, stifling atmosphere from an elongated orbit that will permit both distant (global) and high-resolution views. The science orbit will be established about a month after Venus Express' arrival, and the primary mission is planned to last until September 2008. Following is a timeline of the arrival events.

Space-
craft
Time
(UTC)		 Earth Received Time Event
PDT UTC CEST
07:12 00:17 07:17 09:17 Main engine burn begins
The burn of the main engine will last 51 minutes and produce a velocity change of more than 1.2 kilometers per second (4,000 feet per second).
07:38 00:45 07:45 09:45 Occultation begins
Venus Express' path will take it behind Venus as seen from Earth. As a result, the controllers on Earth will lose radio contact for 10 minutes as the engine continues to burn.
07:48 00:55 07:55 09:55 Occultation ends
Venus Express' main engine should still be firing as the occultation ends. Controllers will be searching intently for the spacecraft's signal once it reappears from behind the planet.
08:00 01:07 08:07 10:07 Main engine burn ends
Venus Express will now be in Venus orbit.
09:00 02:07 09:07 11:07 X-band transmitter on
During the orbit insertion maneuver, Venus Express will employ an omnidirectional S-band antenna. After orbit insertion, the spacecraft will switch to a higher-bit-rate X-band antenna and begin transmitting information about the spacecraft's health.
  02:30 09:30 11:30 Press conference
An orbit insertion program and this press conference will be carried live on ESA TV.
At the time of Venus orbit insertion, it will take 6 minutes and 46 seconds for signals to travel the 125 million kilometers (78 million miles) from the spacecraft to Earth. Earth received times for the events are given for Pacific Daylight Time (PDT), Universal Time (UTC), and Central European Summer Time (CEST). Visit www.timeanddate.com to convert times to your local time zone.

Assuming the orbit insertion happens according to plan, the spacecraft will attempt to take some data during the hours and days afterward. The first images could be available as early as 24 hours following the arrival. Over the month following the orbit insertion, Venus Express will perform seven maneuvers to establish its science orbit:

Date Activity Velocity Change
(meters per second)
April 15 Pericenter Control Maneuver #1 5.52
April 20 Apocenter Lowering Maneuver #1 189.70
April 23 Apocenter Lowering Maneuver #2 111.98
April 26 Apocenter Lowering Maneuver #3 10
April 30 Apocenter Lowering Maneuver #4 8
May 3 Apocenter Trim 2
May 6 Pericenter Control Maneuver #2 3.15

The Planetary Society will be on hand at the European Space Operations Centre in Darmstadt, Germany to witness the arrival of Venus Express. Also attending will be Tatianna Cwick, Grand Prize winner in The Planetary Society's Venus Express Art Contest. Stay tuned to The Planetary Society Weblog for news and updates about Venus Express' arrival!