Venus Express

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Venus Express was the first European mission to Venus. It was a follow on to Mars Express mission. Many of the instruments on the mission were upgraded versions of those on the Mars Express platform.

Venus Express Picture

Mission

Venus Express was launched on a Soyuz-Fregat rocket from the Baikonur Cosmodrome, Kazakhstan on 9 November, 2005. The cruise to Venus took 153 days. The spacecraft entered Venusian orbit in April 2006. Once captured by Venusian gravity, the spacecraft manoeuvred into its operational orbit. The mapping mission was planned to last for 2 Venusian days, about 500 Earth days. It actually lasted more than 9 years.

Venus Express was a European Space Agency mission. The main contractor was EADS Astrium, Toulouse, France which also lead a team of 25 subcontractors from 14 European countries.

The aim of the Venus Express was:

1. To study the atmosphere and plasma environment of Planet Venus from orbit.

2. To investigate the role played by the greenhouse effect in creation of the atmosphere.

3. To study the behaviour and characteristics of cloud and haze formation at different altitudes.

4. To study the Venus’ weak magnetic field.

5. To study high radio wave reflectivity areas on the surface.

6. To search for the possibility of volcanic or seismic activity.

7. To investigate why Venus rotates backwards and so slowly, just one revolution every 243 Earth days.

8. To investigate the mysterious ultraviolet absorption features at an altitude of about 80 kilometres.

Venus Express Spacecraft

The Venus Express used a three-axis stabilised spacecraft design and was based on the Mars Express satellite bus. Only minor changes from Mars Express were required to accommodate the instruments payload.

Venus Express orbited at half the distance to the Sun as compared to Mars. The spacecraft required some design changes to make it more suitable for operating around Venus. In comparison to Mars Express, the radiators on the surface of Venus Express were increased in area and efficiency since the heating of the spacecraft is four times greater.

In comparison to Mars Express, Venus Express needed more energy to brake and be captured into orbit around Venus since the gravity of Venus is almost the same as Earth’s and is about eight times higher than that of Mars.

Specs:

Launch Mass: 1270 kg (including 93 kg orbiter payload and 570 kg fuel)
Spacecraft Bus Dimensions: 1.5 x 1.8 x 1.4 m
Thrust of Main Engine: 400 N
Attitude Thrusters: Two sets of four, each delivering 10 Newtons each
Power Storage: Three lithium-ion batteries
Antennas: Two high-gain dishes, HGA1 = 1.3 m diameter, HGA2 = 0.3 m in diameter, 2 low-gain antennas
Total Mission Cost: 220 million euros ($262 million U.S. 2005).

The Venus Express Mission Control Centre (VMOC) was located at ESOC, ESA’s control centre, in Darmstadt, Germany. After launch, the antenna dishes at the European deep-space ground stations at Villafranca, Spain, New Norcia, West Australia and Kourou, French Guiana were used for communications. When the Venus Express spacecraft reached Venus orbit, communication was be done using the antenna dish located at Cebreros near Madrid, Spain. The New Norcia, Western Australia antenna was also used to support the Venus Radio science experiment (VeRa).

Instruments

Most of the instruments on Venus Express were re-using designs and/or spare hardware originating from either Mars Express or Rosetta Spacecraft. The instruments are provided by collaborative efforts between scientific institutes in ESA member states and Russia.

1. Analyser of Space Plasma and Energetic Atoms (ASPERA) (Institute of Space Physics, Kiruna, Sweden):
ASPERA investigated the interaction between the solar wind and the atmosphere of Venus by measuring outflowing particles from the planet’s atmosphere and the particles making up the solar wind.
Heritage: Mars Express (ASPERA-3)

2. Planetary Fourier Spectrometer (PFS): (Rome, Italy)
PFS measured the temperature and composition measurements of the atmosphere and the surface temperature.
Heritage: Mars Express (PFS)

3. Ultraviolet and Infrared Atmospheric Spectrometer (SPICAV) (France, Belgium, Russia)

SPICAV assisted in the analysis of Venus’s atmosphere. It searched for the small quantities of water expected to exist in the Venusian atmosphere. It also looked for sulphur compounds and molecular oxygen in the atmosphere.
Heritage: Mars Express (SPICAM)

4. Ultraviolet/Visible/Near-Infrared mapping spectrometer (VIRTIS) (Italy, France)

VIRTIS studied the composition of the lower atmosphere between 40 kilometres altitude and the surface. It tracked the clouds in both ultraviolet and infrared wavelengths and allowed scientists to study atmospheric dynamics at different altitudes.
Heritage: Rosetta (VIRTIS)

5. Venus Radio Science Experiment (VeRa) (Germany)
VeRa was a radio sounding experiment that transmitted radio waves from the spacecraft and reflected them off the surface or passed them through the atmosphere.
Heritage: Rosetta (RSI).

6. Venus Monitoring Camera (VMC) (Germany)
VMC was a wide-angle multi-channel camera that was used to take images of the planet in the near infrared, ultraviolet and visible wavelengths. It assisted in the identification of phenomena seen by other instruments.
Heritage: Newly developed for Venus Express

7. Magnetic Field Measurements (MAG) (Austria)
Mag measured the strength of Venus’s magnetic field and the direction of it as affected by the solar wind.
Heritage: Rosetta Lander (ROMAP)

Mission History

Venus Express mission was proposed in March 2001 after ESA asked for proposals suggesting how to reuse the design of the Mars Express spacecraft.

On 28 January 2003, EADS Astrium officially signed the Venus Express contract with the European Space Agency (ESA) worth 82.4 million Euros for the design and development of the spacecraft

30 September 2004: Venus Express spacecraft is complete

10 August 2005: Venus Express arrives in Baikonur Cosmodrome

8 September 2005: Venus Express electrical tests complete.

11 April 2006: Successful VOI Manoeuvre. After a 153 day cruise to Venus the spacecraft entered Venusian orbit.

May 2006: Final Operational Orbit

8 April 2010: Emissivity measurements carried out with the VIRTIS instrument aboard the European Space Agency’s Venus Express spacecraft indicate that Venus has been volcanically active in recent geological times.

16 December 2014: European Space Agency ended the mission in December 2014.

Did you know?

* Soyuz/Fregat rocket was built by Starsem, a European/Russian launcher consortium.

* ESA relied on NASA’s Deep Space Network up until 2002. Independent access to deep space was identified as a necessity. In 2002, ESA’s first deep-space antenna located in New Norcia, West Australia began operations. ESA’s second deep-space radio antenna opened on 28 September, 2005 at Cebreros (Avila, Spain). The first task of Cebreros was tracking the Venus Express spacecraft.

Related Books

Atlas of Venus by Peter Cattermole (Author), Patrick Moore (Author)
From Amazon.com, Amazon.co.uk

Venus II: Geology, Geophysics, Atmosphere, and Solar Wind Environment (Space Science Series) by D. M. Hunten
From Amazon.com, Amazon.co.uk

Europe’s Space Programme: To Ariane and Beyond by Brian Harvey
from Amazon.com, Amazon.co.uk, Amazon.ca

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