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European spacecraft tracking turbulence at Venus EUROPEAN SPACE AGENCY NEWS RELEASE Posted: April 3, 2007 New images and data from the European Space Agency's mission to Venus provide new insights into the turbulent and noxious atmosphere of Earth's sister planet. What causes violent winds and turbulences? Is the surface topography playing a role in the complex global dynamics of the atmosphere? Venus Express is on the case.
At the poles things get really complicated with huge double-eyed vortices providing a truly dramatic view. In addition, a layer of dense clouds covers the whole planet as a thick curtain, preventing observers using conventional optical means from seeing what lies beneath. Venus Express is on the contrary capable of looking through the atmosphere at different depths, by probing it at different infrared wavelengths. The Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board is continuing its systematic investigation of Venus' atmospheric layers to solve the riddle of the causes for such turbulent and stormy atmosphere. The images presented with this article focus on Venusian atmospheric turbulences and cloud features, whose shape and size vary with planetary latitudes. At the equator, clouds are irregular and assume a peculiar 'bubble'-shape. At mid latitudes they are more regular and streaky, running almost parallel to the direction of the super rotation with speed reaching more than 400 kilometres per hour. Going higher up in latitude, in the polar region, the clouds end up in entering a vortex shape. With its multi-wavelength eyes, VIRTIS can observe the atmosphere and the cloud layers not only at different depths, but also both in the day- and night-side of the planet - a characteristic that allows an overall assessment of the 'environmental' causes that can be at the origin of such an atmospheric complexity. At the equator, the extremely violent winds of the super-rotation are in constant 'battle' with other kinds of local turbulences, or 'regional' winds, creating very complex cloud structures. One type of regional wind is due to the strong flux of radiation from the Sun reaching the atmosphere of the planet on the day-side. This flux heats up the atmosphere creating convective cells, where masses of warm air move upwards and generate local turbulence and winds. On the night-side there is obviously no flux from the Sun, but the clouds' shape and the wind dynamics are somehow similar to that we see on the day-side. So, scientists are currently trying to understand if there is any mechanism other than 'convection' responsible for the equatorial turbulences, both on the day- and night-side of Venus. For instance, VIRTIS imaged clouds over Alpha Regio, an area close to the equator. This area is characterised by a series of troughs, ridges, and faults that are oriented in many directions, with surface features that can be up to 4 kilometres high. There might be a connection between the surface topography and the local atmospheric turbulence which is observed in this area. This and other hypotheses are being investigated by the Venus Express science teams using data from several instruments. Actually, the Venusian topography may play an important role also in the global atmospheric dynamics. Understanding this surface-atmosphere connection is one of the major objectives of Venus Express - something to be verified in the whole course of the mission. |
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After nearly a year in space, the European Retrievable Carrier (EURECA) satellite was plucked from orbit and stowed aboard Endeavour for return to Earth during STS-57. The June 1993 mission also featured the first flight of the commercial Spacehab module outfitted with a range of microgravity experiments for the crew to use. A spacewalk to demonstrate working on the end of the shuttle robot arm was performed as well.
Working in two shifts around the clock, the astronauts of shuttle mission STS-56 conducted extensive observations of the Earth's atmosphere using the ATLAS 2 payload in the spring of 1993. The SPARTAN Sun-studying satellite was deployed and then retrieved during Discovery's flight too. The crew narrates the highlights in this presentation.
Space shuttle Endeavour lofted another Tracking and Data Relay Satellite into orbit for NASA during a January 1993 mission. An Inertial Upper Stage boosted the craft toward geosynchronous orbit. Other highlights from STS-54 included a mobility-testing spacewalk and an educational project to demonstrate the physics behind toys in space. The crew narrates this post-flight film.
The Laser Geodynamics Satellite (LAGEOS), a small ball-shaped spacecraft designed to help earthquake research by monitoring the movements of the Earth's crustal plates, was launched from space shuttle Columbia in October 1992. The crew of STS-52 narrate the highlights of the mission, which included Canadian and microgravity experiments.
In advance of launching the Expedition 15 mission to the International Space Station, NASA officials preview the flight's objectives and challenges in this news briefing held March 27 at Johnson Space Center.
As the International Space Station's Expedition 14 winds down, officials managing the flight from Mission Control in Houston hold this retrospective briefing to talk about the mission.
The 50th flight of the space shuttle took place in September 1992. Endeavour's mission featured the Spacelab-J research module for Japan, as well as the first black female astronaut and the first married couple to fly together in space. The crew narrates the highlights in their post-flight film.
Shuttle Atlantis' summer 1992 flight provided the chance to test a revolutionary payload -- the Tethered Satellite System. A snag in the tether prevented a small satellite from reeling miles away from the shuttle as planned, the partial deployment showed power generation using the shoelace-size tether could work. The STS-46 mission also released the European Retrievable Carrier spacecraft to begin a year-long stay in orbit. The astronauts narrate highlights from the flight in this movie.