| In This Page |
|---|
| Venus Express Launch Video |
| Why Venus? |
| The Instruments |
| The Spacecraft |
| The Trajectory and Orbit |
| US Participants |
The Venus Express Mission
Watch Venus Express Launch Video
Why Venus
Missions to Venus have been generally more successful than the missions
to Mars: to date, thirteen Soviet and four atmospheric entry craft and
landers have probed the deep atmosphere of Venus, and two orbiters have
explored its atmosphere and surface, including Pioneer Venus, Venera 15,
Venera 16 and Magellan. In addition, two balloons (Vega 1 and Vega 2)
have flown in the atmosphere of Venus.
But, perhaps more compelling, Venus is a planet with incredible charisma
and a history of contribution to key scientific discoveries, including
both the heliocentric nature of the solar system and estimations of the
speed of light. Interest in Venus remains relevant today, perhaps more
so because of what the planet, so similar to our own, can tell us about
the Earth's evolution, atmosphere, and possibly even future.
Further study is necessary to understand the condition of the planet,
radar map the surface, and solve the great number of Venus' mysteries.
To this end, the Venus Express mission is engaged in a global investigation
of Venus' atmosphere, plasma environment, and some important aspects of
its geology and surface physics.
Key Questions:
If Venus and Earth formed in the same neighborhood of the Sun, why has Venus evolved so differently from Earth despite their many similarities?
Other Questions:
Venus and Earth have much in common but have significant differences in physical characteristics. These differences that have been determined from previous missions to Venus and Earth based observations lead to the following questions that Venus Express mission scientists want to explore with relevant observations.
- What role does the greenhouse effect play in the past, present, and in the future?
- What is the global thermal balance of the planet?
- How does the cloud system work?
- How did the atmosphere of Venus evolve?
- What are the behavior and characteristics of the clouds and hazes at the different levels?
- What is the origin of the UV markings in the clouds? What is the absorber?
- What is driving the rapid rotation of the atmosphere of Venus?
- What causes the circulation to be organized as a hemispheric vortex?
- What are the evolutionary and escape processes of water?
- How do the global dynamics of the planet work?
- Is there presently volcanic or seismic activity?
- What is the origin of the highly radar reflective areas on the surface?
Science Objectives of Venus Express Mission
Venus Express will investigate:
- The structure of Venus' atmosphere
- The composition and chemistry of Venus' atmosphere
- Dynamics of Venus' atmosphere
- The radiative balance on Venus
- The plasma environment and escape processes
- Venus' surface properties and geology
The Spacecraft
 Venus
Express |
 Spacecraft
Cutaway |
- Minor modifications to the Mars Express spacecraft (smaller solar panels and HGA, thermal design)
- Box-like structure 1.7 x 1.7 x1.4 meters
- Max launch mass 1270 kg
- Available solar power 800W @ Earth, 1370W @ Venus
- 3 x 24 Ah Li-Ion Batteries
- Telemetry link 14-230 kbps
- Mass memory 12 Gbit
- 400 N main engine, 2 x 4 x 10 N thrusters
The Instruments
ASPERA-4
ASPERA (Analyser of Space Plasmas and Energetic Atoms) will investigate the interaction between Venus' atmosphere and the solar wind by measuring the outflow of particles from both.
MAG
MAG (a magnetometer) will measure Venus' magnetic field, induced by the interaction between the solar wind and the atmosphere. It will also help understand the effect of the magnetic field on the planet's atmosphere.
PFS
PFS( Planetary Fourier Spectrometer) will measure the temperature of the atmosphere between 55 and 100 km of altitude. It will also measure surface temperature, a possible indicator of volcanic activity, and measure the composition of the atmosphere.
SPICAV/SOIR
SPICAV (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) will determine the density and temperature of the atmosphere between 80 and 180 km of altitude. It will also look for water, sulfur compounds, and oxygen molecules in the atmosphere.
VeRa
VeRa (Venus Radio Science) will investigate the ionosphere of Venus using the radio link between the VEX spacecraft and Earth. This will allow the study of density, temperature and pressure of the atmosphere at 35-100 km. It will also provide information about the solar wind in the inner Solar System.
VIRTIS
VIRTIS (Visible Infrared Thermal Imaging Spectrometer) will study the composition of the lower atmosphere below the cloud decks at 35-40 km. It will also track clouds at various altitudes in ultraviolet and infrared wavelengths to study atmospheric dynamics.
VMC
VMC (Venus Monitoring Camera) is a camera capable of taking pictures at near infrared, ultraviolet, and visible wavelengths simultaneously. It will be able to produce global images, study cloud dynamics, and image the surface. It will also assist other instruments in identifying phenomena.
The Trajectory and Orbit
- 24 hours period
- 250-400 km pericenter altitude
- 66,000 km apocenter altitude
- 90 degree inclination
- Pericentre latitude ~80 degreeN
- 7-10 hours communication link per orbit
