ESA Science & Technology - Publication Archive
Venus Express was launched in late October, 2005, and arrived at the planet in April 2006, where it is now in orbit and the return to Earth of new information about Venus' atmosphere, surface, and space environment has begun. The purpose of this special issue of Planetary and Space Science is to lay out the background to the mission, in terms of the planet and its mysteries as well as the spacecraft, its instruments, and the planned observations, in order to review the context in which the new results will be analysed and interpreted.
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ESA's ambition of inter-planetary exploration using a fast-track low cost industrial programme was well achieved with Mars Express. Reusing the platform architecture for the service module and specifically the Propulsion system enabled Venus Express to benefit from several lessons learnt from the Mars Express experience. Using all existing components qualified for previous programmes, many of them commercial telecommunication spacecraft programmes with components available from stock, an industrial organisation familiar from Mars Express was able to compress the schedule to make the November 2005 launch window a realistic target. While initial inspection of the CPS schematic indicates a modified Eurostar type architecture, - a similar system using some Eurostar components - would be a fairer description. The use of many parts of the system on arrival at the destination (Mars or Venus in this case) is a departure from the usual mode of operation, where many components are used during the initial few weeks of GTO or GEO. The system modifications over the basic Eurostar system have catered for this in terms of reliability contingencies by replacing components, or providing different levels of test capability or isolation in flight. This paper aims to provide an introduction to the system, address the evolution from Eurostar, and provide an initial assessment of the success of these modifications using the Mars Express experience, and how measures have been adopted specifically for Venus Express.
An insufficient amount of pressurant gas in the propulsion system or a working temperature in the pressurant tank outside the qualification limits can cause a decrease in the performance of the thrusters or even the loss of the mission. This paper presents an engineering tool used able to compute the Pressurant budget of a mission and the effects of influencing parameters. The updated tool allows to also compute the temperature, pressure and mass evolution inside the pressurant tank during the various mission phases. The tool has been used to verify the calculations done by Astrium Stevenage for Mars Express and Venus Express. The pressurant gas used for both cases was helium. The tool permits to use other combinations of pressurant gases and propellants for different propellant systems (monopropellant and bipropellant systems).
A new concept of a high-resolution near-IR spectrometer consisting of an echelle grating combined with an acousto-optic tunable filter (AOTF) for separation of diffraction orders, is developed for space-borne studies of planetary atmospheres. A compact design with no moving parts within the mass budget of 3-5 kg allows to reach the resolving power 20 000-30 000. Only a small piece of spectrum in high diffraction orders can be measured at a time, but thanks to flexibility of the AOTF electrical tuning, such pieces of spectrum can be measured randomly and rapidly within the spectral range. This development can be used for accurate measurements of important atmospheric gases, such as CO2 in terrestrial atmosphere, isotopic ratios and minor gases. A spectrometer, based on this principle, SOIR (Solar Occultation InfraRed) is being built for Venus Express (2005) ESA mission. Instruments based on this principle have high potential for the studies of the Earth, in particular for measurements of isotopes of water in the lower atmosphere, either in solar occultation profiling (tangent altitude <10 km), or observing solar glint for integral quantities of the components. Small size of hardware makes them ideal for micro-satellites, which are now agile enough to provide necessary pointing for solar occultation or glint observations. Also, the atmosphere of Mars has never been observed at local scales with such a high spectral resolution. A laboratory prototype consisting of 275-mm echelle spectrometer with Hamamatsu InGaAs 512-pixel linear array and the AOTF has demonstrated a resolving power of 30 000 in the spectral range of 1-1.7 µm. The next set up, covering the spectral ranges of 1-1.7 µm and 2.3-4.3 µm, and the Venus Express SOIR are briefly discussed.
A paper originally presented by EADS Astrium at the 55th IAC in Vancouver in October 2004.
On October 26th of next year, Venus Express spacecraft will depart from Baikonur on-board the Soyuz/Fregat Launch Vehicle. It will be the very first European mission to the "morning star", two years after the first European trip to Mars. Venus Express will carry 7 science payloads dedicated to global investigation of the Venusian atmosphere.
A paper originally presented by EADS Astrium at the 54th IAC in Bremen in September 2003.
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. This will be the first European spacecraft to visit the planet Venus. Venus Express is scheduled for launch from the Baikonour Cosmodrome in Kazakhstan in November 2005. It will be launched by a Soyuz-Fregat rocket and put immediately into its transfer orbit to Venus.