sábado, 7 de março de 2015

Vênus, a Bela da Tarde, e Venus Express, entrando e saindo de cena

Olá!

Nessas noites em que a Lua vem chegando mais e mais tardia,
por que não aproveitarmos para bem  observarmos
a maravilhosa Vênus, a Bela da Tarde,
nos chamando através seu brilho intenso
no horizonte oeste,
ao cair da noite?

Se você estiver em um lugar bem plano,
poderá, inclusive, ainda observar Marte
 já quase escondendo-se de nossos olhares...
E sabemos que entre Marte e Vênus
encontra-se Urano, mas não podemos  vê-lo a olho nu,
que pena, somente através um simpático telescópio
e penso que a luminosidade ainda presente do Sol que já se refugiou atrás
do horizonte oeste não nos permitirá esta observação.

Nesta Postagem, Caro Leitor,
encontre alguma informação sobre
a Missão Venus Express -
Missão realizada pela ESA, a Agência Espacial Européia, 
e designada para estudar a atmosfera desse Planeta, desde a superfície até a ionosfera.

Venus Express foi lançada em novembro de 2005, alcançando Vênus em abril de 2006.
Infelizmente, ao final do ano de 2014, seu combustível terminou
e a Missão encontrou seu final, após 8 anos de inestimáveis serviços
e tendo realizado suas tarefas muito além do planejado...,
saindo de cena de forma gloriosa.

Com um abraço estrelado,
Janine Milward



Programa Stellarium

Programa Stellarium

Programa Stellarium


Programa Stellarium

Programa Stellarium

Programa Stellarium

Programa Stellarium




VENUS EXPRESS
- entrando e saindo de Cena




VENUS EXPRESS OBJECTIVES

Thanks to a set of state-of-the-art instruments for planetary investigations, Venus Express will dig into the secrets of the Venusian atmosphere.
It will study its complex dynamics and chemistry, and the interactions between the atmosphere and the surface, which will give clues about surface’s characteristics.
It will also study the interactions between the atmosphere and the interplanetary environment (solar wind) to better understand the evolution of the planet.
In the most comprehensive study of the Venusian atmosphere ever, Venus Express will address many open questions:
  • How do the complex global dynamics of the planet work?
    - What causes the super-fast atmospheric rotation and the hurricane-force winds?
    - What maintains the double atmospheric vortex at the poles?
  • How does the cloud system work?
    - How do clouds and haze form and evolve at different altitudes?
    - What is at the origin of mysterious ultraviolet marks at the clouds tops?
  • What processes govern the chemical state of the atmosphere?
  • What role does the ‘green-house effect’ play in the global evolution of the Venusian climate?
  • What governs the escape processes of the atmosphere?
  • Are there water, carbon dioxide or sulphuric acid cycles on Venus?
  • What caused the global volcanic resurfacing of Venus 500 million years ago?
  • Why are some areas on the surface so reflective to radar?
  • Is there present volcanic or seismic activity on the planet?


http://www.esa.int/spaceinimages/Images/2013/01/Visiting_Venus

Access the video  http://www.esa.int/spaceinvideos/Videos/2013/01/A_day_in_the_life_of_Venus_Express
  • Title A day in the life of Venus Express
  • Released 21/01/2013
  • Length 00:00:12
  • Language English
  • Footage Type Animation
  • Copyright ESA/MPS/DLR/IDA, M. Pérez-Ayúcar & C. Wilson
  • DescriptionThe Venusian cloud tops during nearly a full orbit of ESA’s Venus Express around the planet. The inset shows the corresponding position and relative speed of Venus Express as it approaches from its furthest distance of 66 000 km above the south pole, swooping down to 250 km above the north pole.
    The images were captured by the Venus Monitoring Camera on 7–8 January 2012 and are shown in false colour. The video was compiled using public data from the Venus Express data archive and was released as an ESA space science image of the week feature.
  • http://www.esa.int/spaceinvideos/Videos/2013/01/A_day_in_the_life_of_Venus_Express

A DAY IN THE LIFE OF VENUS EXPRESS

21 January 2013
Bright and dark cloud bands wind around the poles of Venus in this beautiful sequence tracked by ESA’s Venus Express as it makes a rollercoaster orbit around the planet.
We join the spacecraft from a staggering 66 000 km above the south pole, staring down into the swirling south polar vortex. From this bird’s-eye view, half of the planet is in darkness, the ‘terminator’ marking the dividing line between the day and night sides of the planet.
Intricate features on smaller and smaller scales are revealed as Venus Express dives to just 250 km above the north pole and clouds flood the field of view, before regaining a global perspective as it climbs away from the north pole.
..................................................................




Goals: The European Space Agency's Venus Express was designed to study the atmosphere of Venus, from the surface to the ionosphere. The mission reused the same design as ESA's Mars Express and spare parts from other deep space missions.

Accomplishments: After arriving at Venus in April 2006, Venus Express logged many firsts. One of the most significant findings were signs that Venus had been volcanically active in the last three million years -- suggesting the planet may still be geologically active.

The orbiter also made extensive meteorological maps of Venus, providing measurements of wind fields and temperatures and the chemical composition of the atmosphere. The spacecraft found a striking double-eyed atmospheric vortex that dominates the south pole. It detected water molecules escaping into space, found concrete evidence for lightning in the Venusian atmosphere and provided infrared glimpses of the hot surface.
Venus Express, after running out of propellant, ended its mission in December 2014.
http://solarsystem.nasa.gov/missions/profile.cfm?Sort=Alpha&Letter=V&Alias=Venus%20Express&Target=Venus







Venus Express lifts off on time at 04:33 CET
9 November 2005
Venus Express was launched at 04:33 CET by a Soyuz-Fregat rocket, from the Baikonur Cosmodrome in Kazahkstan.
http://www.esa.int/Our_Activities/Space_Science/Venus_Express/Venus_Express_launched






2006 July 17
See Explanation.  Clicking on the picture will download
 the highest resolution version available.
Venus Express Arrives at Venus 
Credit: ESA/MPSKatlenburg-LindauGermany
Explanation: Humanity now has a spacecraft orbiting Venus. The robotic Venus Express spacecraft launched by the European Space Agency in 2005 November arrived at Venus in 2006 April. Venus Express is now orbiting Earth's sister planet and returning pictures. Pictured above is a false-color, time-lapse movie in ultraviolet light captured by the Venus Express spacecraft as it flew over Venus' northern hemisphere in late May. Venus Express is scheduled to orbit Venus for three years and collect data that might help in answering questions that include why Venus continually generates hurricane-force winds, why Venus became so hot in the past, and if there is any current volcanic activity on Venus. It is hoped that a better understanding of Venus's hot and inhospitable climate will help humanity better understand Earth's climate as well.





Venus Express Anomaly
On 28 November 2014, the flight control team at ESOC reported loss of contact with Venus Express.
It is possible that the remaining fuel on board VEX was exhausted during the recent periapsis-raising maneuvers and that the spacecraft is no longer in a stable attitude (the spacecraft's high-gain antenna must be kept pointed toward Earth to ensure reliable radio contact).
Repeated attempts to re-establish contact using ESA and NASA deep-space tracking stations have been made since then, and there has been some limited success in the period since 3 December.
Although a stable telemetry link is not available, some telemetry packets were successfully downlinked. These confirm that the spacecraft is oriented with its solar arrays pointing toward the Sun, and is rotating slowly.
The operations team is currently attempting to downlink the table of critical events that is stored in protected memory on board, which may give details of the sequence of events which occurred over the past few days. The root cause of the anomaly (fuel situation or otherwise) remains to be established.
We will provide an update as soon as something more concrete is known.
Today, Venus Express is in the eighth year of its fantastic mission - pretty good for a satellite originally designed for just two years of orbiting in Venus' challenging conditions.

Venus Express Goes Gently Into the Night
ESA's Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.
Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24-hour orbit, travelling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.
However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.
...................................................................................................


Venus Express goes gently into the night

16 December 2014 ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year. 


http://www.esa.int/Our_Activities/Space_Science/Venus_Express
















16 December 2014
ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year. 
Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24‑hour orbit, traveling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.
However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.
Normally, the spacecraft would perform routine thruster burns to ensure that it did not come too close to Venus and risk being lost in the atmosphere. But this unique adventure was aimed at achieving the opposite, namely reducing the altitude and allowing an exploration of previously uncharted regions of the atmosphere.

Venus Express aerobraking
The campaign also provided important experience for future missions – aerobraking can be used to enter orbit around planets with atmospheres without having to carry quite so much propellant.
Between May and June 2014, the lowest point of the orbit was gradually reduced to about 130–135 km, with the core part of the aerobraking campaign lasting from 18 June to 11 July.
After this month of ‘surfing’ in and out of the atmosphere at low altitudes, the lowest point of the orbit was raised again through a series of 15 small thruster burns, such that by 26 July it was back up to about 460 km, yielding an orbital period of just over 22 hours.
The mission then continued in a reduced science phase, as the closest approach of the spacecraft to Venus steadily decreased again naturally under gravity.
Under the assumption that there was some propellant still remaining, a decision was taken to correct this natural decay with a new series of raising manoeuvres during 23–30 November, in an attempt to prolong the mission into 2015.
However, full contact with Venus Express was lost on 28 November. Since then the telemetry and telecommand links had been partially re-established, but they were very unstable and only limited information could be retrieved.
“The available information provides evidence of the spacecraft losing attitude control most likely due to thrust problems during the raising manoeuvres,” says Patrick Martin, ESA’s Venus Express mission manager.
“It seems likely, therefore, that Venus Express exhausted its remaining propellant about half way through the planned manoeuvres last month.” 
...................................................................

SAIBA MUITO MAIS SOBRE VENUS EXPRESS,
ACESSANDO  http://www.esa.int/Our_Activities/Space_Science/Venus_Express/








http://www.esa.int/Our_Activities/Space_Science/Venus_Express/Venus_Express_goes_gently_into_the_night





   

Date
Title
Source
16 Dec 2014Venus Express Goes Gently Into the NightESA
5 Dec 2014Venus Express AnomalyEuropean Space Agency
16 May 2014Venus Express Gets Ready to Take the PlungeESA
20 Jun 2013ESA Science Missions Continue in OvertimeESA
18 Jun 2013The Fast Winds of Venus Are Getting FasterESA
18 Jun 2013Super-Hurricane-Force Winds on Venus are Getting StrongerESA
24 Mar 2013Venus Vortices Go For Chaotic Multi-Storey Strolls Around The PolesUniversidad Del Pais
2 Dec 2012A new episode of active volcanism on Venus?ESA
12 Apr 2010Venus VolcanoesVenus Volcanoes
9 Feb 2009ESA Missions ExtendedEuropean Space Agency
30 May 2008New Details on Venusian Clouds RevealedEuropean Space Agency
15 May 2008Key Molecule Discovered in Venus's AtmosphereEuropean Space Agency
21 Feb 2008The Light and Dark of VenusEuropean Space Agency
28 Nov 2007NASA Scientist Confirms Light Show on VenusNASA/ESA/JPL
10 Oct 2007New Isotope Molecule May Add to Venus' Greenhouse EffectEuropean Space Agency
4 Jun 2007Venus Express and MESSENGER to Look at Venus in TandemEuropean Space Agency
23 May 2007Ground-based Observatories Join Forces with Venus ExpressEuropean Space Agency
7 May 2007Venus Express' Infrared Camera Goes FilmingEuropean Space Agency
11 Apr 2007One Year at Venus, and Going StrongEuropean Space Agency
4 Apr 2007Tracking Alien Turbulences with Venus ExpressEuropean Space Agency
14 Dec 2006Hot Stuff on Venus!European Space Agency
9 Nov 2006Happy Anniversary, Venus Express!European Space Agency
13 Oct 2006Complex Meteorology at VenusEuropean Space Agency
12 Jul 2006Science Updates From Venus ExpressEuropean Space Agency
29 Jun 2006Double Vortex at Venus South Pole UnveiledEuropean Space Agency
http://solarsystem.nasa.gov/news/archive.cfm?Mission=Venus_Express










Date
Title
Source
9 May 2006Venus Express has Reached Final OrbitEuropean Space Agency
14 Apr 2006Unexpected Detail in First-Ever Venus South Pole ImagesEuropean Space Agency
11 Apr 2006Venus Express Enters Orbit Around The Hothouse PlanetEuropean Space Agency
10 Apr 2006ESA's Venus Express To Reach Final DestinationEuropean Space Agency
31 Mar 2006Venus Within ESA Probe ReachEuropean Space Agency
17 Feb 2006Successful Venus Express Main Engine TestEuropean Space Agency
9 Nov 2005Venus Express en route to Probe the Planet's Hidden MysteriesEuropean Space Agency
24 Oct 2005European Space Agency's Venus Express Launch DelayedEuropean Space Agency
18 Oct 2005The European Space Agency's Venus Express Ready for Lift-offEuropean Space Agency
5 Oct 2004First Look: Venus ExpressEuropean Space Agency






Com um abraço estrelado,
Janine Milward