Mariner 10 121k
gif
Viking gif
Galileo gif
Voyager
lista a seguir contém apenas as naves espaciais de interesse para a ciência planetária. A lista está longe de ser completa (para mais detalhes, veja abaixo. Grande parte do que se segue foi adaptada de sci.space FAQ.
( mais informações, NASA Spacelink)
Ainda estamos rastreando ambas as naves, e elas devem continuar a funcionar, embora suas baterias estejam se esgotando. A Pioneer 11 provavelmente perderá sua energia até o final de 1995; a Pioneer poderá durar mais alguns anos. Elas estão penetrando no espaço interestelar - a primeira façanha dessa natureza já realizada pelo homem.
Como as primeiras naves a deixar nosso sistema solar, as Pioneers 10 e 11 levam uma mensagem na forma de uma placa anodizada de ouro, de 6 x 9 pol., afixada à sua estrutura principal.
( página inicial Projeto Pioneer , e mais sobre as sondas Pioneer 10 e Pioneer 11 ,através da NASA Spacelink; situação atual, NASA Ames)
(mais na página da web, JPL)
( mais informações , NASA Spacelink; tutorial, UCLA)
A Viking Lander 1 fez sua última transmissão em 11 de novembro de 1982. O controladores de vôo da JPL tentaram, por mais seis meses e meio, retomar o contato com a Viking Lander 1, mas não conseguiram. A missão chegava assim a seu término, em 21 de maio de 1983.
Um detalhe interessante: o lander da Viking 1 tinha sido projetado pela Thomas A. Mutch Memorial Station em memória do falecido líder da equipe de formação de imagens da lander. O National Air and Space Museum , em Washington, DC, é responsável pela guarda da placa da Mutch Station, até que ela possa ser afixada à espaçonave por uma missão tripulada.
(mais informações e uma página da Web, JPL)
Entre as duas missões Voyager, nosso conhecimento dos quatro planetas gigantes, seus satélites e anéis, aumentou consideravelmente. As Voyager 1 & 2 descobriram que Júpiter apresenta complexos fenômenos atmosféricos, relâmpagos e auroras. Três novos satélites foram descobertos. Duas grandes surpresas: Júpiter tem anéis e Io tem vulcões ativos, com significativos efeitos na magnetosfera joviana.
Quando as sondas chegaram a Saturno, elas descobriram mais de 1000 pequenos anéis e 7 satélites, inclusive os satélites pastores previstos, responsáveis pela estabilidade dos anéis. O clima era ameno, comparado com o de Júpiter: jatos de vapor com variação mínima (o ciclo de 33 anos da grande mancha /faixa branca é conhecido). A atmosfera de Titã era nevoenta. A aparência de Mimas foi surpreendente: uma maciça cratera de impacto dava-lhe a aparência de Estrela da Morte. A grande surpresa aqui foi o estranho aspecto dos anéis. Trançados, rugas e raios eram tão inesperados quanto inexplicáveis.
Diferente de Urano, verificou-se que a atmosfera de Netuno é bastante ativa, incluindo-se numerosas formações de nuvens. Os arcos anelares observados eram nódulos brilhantes em um dos anéis. Dois outros anéis e seis outros satélites foram descobertos. O eixo magnético de Netuno também era oblíquo. Tritão tinha a aparência de um cantalupo e geysers (o que é líquido a 38k?)
Se não ocorrerem imprevistos, poderemos manter comunicação com ambas as naves pelo menos até o ano 2030. Ambas têm grande quantidade de hidrazina - espera-se que a Voyager 1 tenha suficiente força propulsora até o ano 2040 e a Voyager 2, até 2034. O fator limitante são os RTGs (geradores térmicos de radio-isótopo). A potência de saída dos RTGs está caindo lentamente a cada ano. Por volta do ano 2000, não haverá força suficiente para energizar o espectrômetro de ultravioleta. Até 2010, a energia terá caído a um nível tal, que nem todos os instrumentos de campos e partículas poderão continuar a ser alimentados ao mesmo tempo. Um esquema de distribuição de energia será então acionado. Alguns dos instrumentos (F&P) serão ligados e outros desligados. A nave poderá permanecer operando nesse modo por mais dez anos, após o que, sua energia provavelmente será muito baixa para mantê-la.
(uma ótima "página inicial" na NSSDC; fact sheet e uma página da Web, JPL; informações gerais, NASA/ARC)
Em abril de 1990, a Giotto foi reativada. Três dos instrumentos estavam funcionando perfeitamente, 4 estavam parcialmente danificados mas em condições de uso, o restante, inclusive a câmera, estava inutilizado. A 2 de julho de 1990, a Giotto fez uma máxima aproximação com a Terra e foi redirecionada para um encontro bem sucedido com o cometa Grigg-Skjellerlup, a 10 de julho de 1992.
Os controladores de terra retomaram o controle de nave. Seu potencial para futuras missões está sendo avaliado.
(para mais informações, veja a página inicial Missão Clementine, USGS e a página sobre Clementine , NASA PDA e as outras páginas às quais ela faz referência.)
(mais informações, uma página da Web e uma segunda página da Web do JPL; página Magellan, da NASA PDS; fact sheet, NSSDC)
Both Voyagers are using their ultraviolet spectrometers to map the heliosphere and study the incoming interstellar wind. The cosmic ray detectors are seeing the energy spectra of interstellar cosmic rays in the outer heliosphere
It is now estimated that Voyager 1 will pass the Pioneer 10 spacecraft in January 1998 to become the most distant human-made object in space.
( more info from JPL)
As of December 1 1994, Voyager 1 was 8.7 billion kilometers (5.4 billion miles) from Earth traveling at 61,200 km/hr (39,000 mph) and Voyager 2 was 6.7 billion kilometers (4.2 billion miles) from Earth traveling at 57,600 km/hr (36,000 mph).
Galileo has already returned the first resolved images of two asteroids, 951 Gaspra and 243 Ida, while in transit to Jupiter. It has also returned pictures of the impact of Comet SL9 onto Jupiter from its unique vantage point.
Efforts to unfurl the stuck High Gain Antenna (HGA) have essentially been abandoned. With its Low Gain Antenna Galileo transmits data at about 10 bits per second. JPL has developed a backup plan using enhancements of the receiving antennas in the Deep Space Network and data compression (JPEG-like for images, lossless compression for data from the other instruments) on the spacecraft. This should allow Galileo to achieve approximately 70% of its original science objectives with the much lower speed Low Gain Antenna. Long term Jovian weather monitoring, which is imagery intensive, will suffer the most.
Galileo Schedule
----------------
10/18/89 - Launch from Space Shuttle
02/09/90 - Venus Flyby
10/**/90 - Venus Data Playback
12/08/90 - 1st Earth Flyby
05/01/91 - High Gain Antenna (was to have) Unfurled
07/91 - 06/92 - 1st Asteroid Belt Passage
10/29/91 - Asteroid Gaspra Flyby
12/08/92 - 2nd Earth Flyby
05/93 - 11/93 - 2nd Asteroid Belt Passage
08/28/93 - Asteroid Ida Flyby
07/13/95 - Probe Separation
07/20/95 - Orbiter Deflection Maneuver
12/07/95 - Jupiter/Io Encounter; Europa flyby
07/04/96 10:01 - Ganymede-1
09/06/96 19:01 - Ganymede-2
11/04/96 13:30 - Callisto-3
11/06/96 18:42 - Europa-3A ("non-targeted" flyby @32,000 km
on the same orbit as Callisto-3)
12/19/96 06:56 - Europa-4
01/20/97 01:13 - Europa-5A (flyby @27,400 km during solar
conjunction - counts for gravity - not science)
02/20/97 17:03 - Europa-6
04/04/97 06:00 - Europa-7A ("non-targeted" @23,200 km on the
Ganymede-7 orbit)
04/05/97 07:11 - Ganymede-7
05/06/97 12:12 - Callisto-8A ("non-targeted" @33,500 km on
the Ganymede-8 orbit)
05/07/97 15:57 - Ganymede-8
06/25/97 13:48 - Callisto-9
06/26/97 17:20 - Ganymede-9A ("non-targeted" @80,000 km on
the Callisto-9 orbit)
09/17/97 00:21 - Callisto-10
11/06/97 21:47 - Europa-11
(more details)
The magnetotail passage occurs on the long orbit between Callisto 9 and
10. Galileo will also obtain a few images of Jupiter's ring system and
some of its smaller satellites.
The closest approaches to the Galilean satellites (as compared to Voyager) are:
Voyager Galileo (targeted) Galileo (non-targeted) Io 20,570 km 1,000 km -- Europa 205,720 588 23,200 Ganymede 62,130 255 80,000 Callisto 126,400 416 33,500For the Galileo camera a distance of 50,000 km yields a resolution of 1 km, so the non-targeted flybys (along with the distant phase of approach and departure to the targeted flybys) will give the large amount of coverage at 1/2 to 2 km resolution, and the close approach phase of the targeted flybys will give on the order of dozens to hundreds of frames of medium and high resolution (<200 m and <80 m respectively). Galileo will pass by Jupiter at a distance of only 214,000 km from the cloud tops on its first "perijove" on 7-Dec-1995
(Galileo page from NASA PDS; the Galileo Home Page and more info from JPL; newsletter; web page; NSSDC page)
Named for the American astronomer Edwin Hubble.
Much, much more information about HST and HST pictures are available at the Space Telescope Science Institute. HST's latest images are posted regularly. (Here is a brief history of the HST project. There's also some more HST info at JPL.)
(Ulysses Home Pages from JPL and ESA; a Fact Sheet from JPL; yet more info )
The main scientific goal of the mission is to measure the mass, momentum and energy of the solar wind that somehow is transferred into the space environment around the Earth. Although much has been learned from previous space missions about the general nature of this huge transfer, it is necessary to gather a great deal of detailed information from several strategic regions of space around the Earth before scientists understand the ways in which the planet's atmosphere responds to changes in the solar wind.
The launch also marks the first time a Russian instrument will fly on an American spacecraft. The Konus Gamma-Ray Spectrometer instrument, provided by the Ioffe Institute, Russia, is one of two instruments on Wind which will study cosmic gamma-ray bursts, rather than the solar wind. A French instruments is also aboard.
At first, the satellite will have a figure-eight orbit around the Earth with the assistance of the Moon's gravitational field. Its furthest point from the Earth will be up to 990,000 miles (1,600,000 kilometers), and its closest point will be at least 18,000 miles (29,000 kilometers).
Later in the mission, the Wind spacecraft will be inserted into a special halo orbit in the solar wind upstream from the Earth, at the unique distance which allows Wind to always remain between the Earth and the Sun (about 930,000 to 1,050,000 miles, or 1,500,000 to 1,690,000 kilometers, from the Earth).
An earlier plan for an asteroid fly-by on the way out similar to the highly successful Galileo fly-bys of Ida and Gaspra was scrapped in order to reduce costs.
One of the most intriguing aspects of Titan is the possibility that its surface may be covered in part with lakes of liquid hydrocarbons that result from photochemical processes in its upper atmosphere. These hydrocarbons condense to form a global smog layer and eventually rain down onto the surface. The Cassini orbiter will use onboard radar to peer through Titan's clouds and determine if there is liquid on the surface. Experiments aboard both the orbiter and the entry probe will investigate the chemical processes that produce this unique atmosphere.
Key Scheduled Dates for the Cassini Mission (VVEJGA Trajectory) ------------------------------------------------------------- 10/06/97 - Titan IV/Centaur Launch 04/21/98 - Venus 1 Gravity Assist 06/20/99 - Venus 2 Gravity Assist 08/16/99 - Earth Gravity Assist 12/30/00 - Jupiter Gravity Assist 06/25/04 - Saturn Arrival 11/06/04 - Probe Separation 11/27/04 - Titan Probe Entry 06/25/08 - End of Primary Mission( Cassini page from JPL; Cassini page from NASA PDS; more info from JPL; fact sheetfrom NASA Spacelink; info on the Doppler Wind Experiment on Huygens)
Mars Global Surveyor will be a polar-orbiting spacecraft at Mars designed to provide global maps of surface topography, distribution of minerals and monitoring of global weather.
Launched with a Delta II expendable vehicle from Cape Canaveral, Fla., in November 1996, the spacecraft will cruise 10 months to Mars (arriving in September 1997), where it will be initially inserted into an elliptical capture orbit. During the following four months, thruster firings and aerobraking techniques will be used to reach the nearly circular mapping orbit over the Martian polar caps. Aerobraking, a technique pioneered by the Magellan mission, which uses the forces of atmospheric drag to slow the spacecraft into its final mapping orbit, will provide a means of minimizing the amount of fuel required to reach the low Mars orbit. Mapping operations are expected to begin in late January 1998.
The spacecraft will circle Mars once every two hours, maintaining a "sun synchronous" orbit that will put the sun at a standard angle above the horizon in each image and allow the mid-afternoon lighting to cast shadows in such a way that surface features will stand out. The spacecraft will carry a portion of the Mars Observer instrument payload and will use these instruments to acquire data of Mars for a full Martian year, the equivalent of about two Earth years. The spacecraft will then be used as a data relay station for signals from U.S. and international landers and low-altitude probes for an additional three years.
International participation, collaboration and coordination will enhance all missions of the program. Landers in future years -- 1998, 2001, 2003 and 2005 -- will capitalize on the experience of the Mars Pathfinder lander mission to be launched in 1996. Small orbiters launched in the 1998 and 2003 opportunities will carry other instruments from the Mars Observer payload and will serve as data relay stations for international missions of the future.
The Mars Global Surveyor spacecraft will be acquired from industry through a competitive procurement. The science payload will be provided as government-furnished equipment that was built to duplicate the instruments flown on Mars Observer. The payload includes the Mars orbital camera, thermal emission spectrometer, ultra-stable oscillator, laser altimeter, magnetometer/electron reflectometer and Mars relay system.
The Jet Propulsion Laboratory will manage the project for NASA's Solar System Exploration Division and will provide the mission design, navigation, and conduct mission operations. Tracking and data acquisition will be provided by a 34-meter subnetwork of the worldwide Deep Space Network.
Project costs for the Mars Global Surveyor through 30 days after launch will be approximately $155 million.
(MGS Home Page; from JPL)
Pathfinder is planned for a fiscal year 1994 start by NASA's Office of Space Science with a cost cap of $150 million in fiscal year 1992 dollars. It is the first in NASA's Discovery Program series of low-cost planetary missions.
A small (10-kilogram or 22-pound) rover will be carried by Pathfinder. Funded by the NASA Office of Advanced Concepts and Technology, the rover will perform technology, science and engineering experiments on the Martian surface.
It is scheduled to arrive at Mars in July 1997.
(More info from JPL)
Science objectives include characterizing global geology and geomorphology of Pluto and Charon, mapping both sides of each body, and characterizing Pluto's atmosphere (the atmosphere is freezing out as Pluto moves away from the Sun, so launching early and minimizing flight time is critical for this objective). The 7 kilogram instrument package might include a CCD imaging camera, IR mapping spectrometer, UV spectrometer, and radio science occultation experiments.
The PFF spacecraft would be highly a miniaturized descendant of the present class of outer solar system platforms, breaking the trend of increasingly complex and expensive probes such as Galileo and Cassini.
There's an article about PFF by its designers in the Sep/Oct 1994 issue of The Planetary Report, the bimonthly newsletter from The Planetary Society.
Funding for this project is very much in doubt.
(more info from NASA; Pluto Express home page)
Scheduled for launch in February 1996 aboard a Delta 2 rocket, the NEAR spacecraft should arrive in orbit around asteroid 433 Eros in early January 1999. It will then survey the rocky body for a minimum of one year, at altitudes as close as 15 miles (24 kilometers). Eros is one of the largest and best-observed asteroids whose orbits cross Earth's path. These asteroids are closely related to the more numerous "Main Belt" asteroids that orbit the Sun in a vast doughnut-shaped ring between Mars and Jupiter.
Hermes is a joint effort between JPL and TRW. If it is approved, it will be launched in 1999.
Mariner 10 121k
gif Viking gif Galileo gif
... Sun
... Small
Bodies ... Medium
... Spacecraft ... Plea
... 
