The
aim of the Venus Express is:
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
uses a three-axis stabilised spacecraft design and is based on
the Mars Express satellite bus. Only minor changes from Mars
Express were required to accommodate the instruments payload.
Venus Express will be orbiting 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 have been increased in area and efficiency since
the heating of the spacecraft is four times greater.
In comparison to Mars
Express, Venus Express needs 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) is 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 will be used
for communications. When the Venus Express spacecraft is in
orbit around Venus, communication will be done using the antenna
dish located at Cebreros near Madrid, Spain. The New Norcia
antenna will be used to support the Venus Radio science
experiment (VeRa).
Instruments
Most of the
instruments on Venus Express are 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 will investigate 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 will measure the
temperature of the atmosphere between altitudes of 55?00
kilometres, make composition measurements of the atmosphere and
measure the surface temperature.
Heritage: Mars Express (PFS)
3. Ultraviolet and Infrared Atmospheric Spectrometer (SPICAV)
(France,
Belgium, Russia)
SPICAV will assist in the
analysis of Venus’s atmosphere. It will search for the small
quantities of water expected to exist in the Venusian
atmosphere. It will also look for sulphur compounds and
molecular oxygen in the atmosphere.
Heritage: Mars Express (SPICAM)
4. Ultraviolet/Visible/Near-Infrared mapping spectrometer (VIRTIS)
(Italy, France)
VIRTIS will study the
composition of the lower atmosphere between 40 kilometres
altitude and the surface. It will track the clouds in both
ultraviolet and infrared wavelengths and allow scientists to
study atmospheric dynamics at different altitudes.
Heritage: Rosetta (VIRTIS)
5. Venus Radio Science Experiment (VeRa)
(Germany)
VeRa is a radio
sounding experiment that will transmit radio waves from the
spacecraft and reflect them off the surface or pass them through
the atmosphere.
Heritage: Rosetta (RSI).
6. Venus Monitoring Camera (VMC)
(Germany)
VMC is a wide-angle
multi-channel camera that will be able to take images of the
planet in the near infrared, ultraviolet and visible
wavelengths. It will assist in the identification of phenomena
seen by other instruments.
Heritage: Newly developed for Venus Express
(reusing parts of Mars Express’s High Resolution Stereo Camera
and the Rosetta Optical, Spectroscopic and Infrared Remote
Imaging System (OSIRIS).
7. Magnetic Field Measurements (MAG)
(Austria)
Mag will
measure 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.
Did
you know?
* Soyuz/Fregat rocket is built by Starsem, a
European/Russian launcher consortium.
*
ESA had to rely 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 will open on 28 September, 2005 at Cebreros
(Avila, Spain). The first task of Cebreros will be that of
tracking the Venus Express spacecraft.
