Historic Space Missions
Contrary to what we have learnt, the universe today does not comprise celestial bodies only. Humans have added their bit to it with a number of spacecraft, satellites and planetary cameras that are constantly sending back information to unveil the many mysteries of this cosmos.Who knows what the future will bring? But for now, here is a selection of the space missions currently charting alien voids...
Mass: 970 kilograms (2,140 pounds) total, consisting of 870-kilogram (1,914-pound) satellite (including radar instrument) and 76 kilograms (167 pounds) of thruster propellantOverviewScatterometer, the ocean-observing satellite was built in record time of 12 months, after Nasa Scatterometer (NSCAT) instrument on Japan's Midori satellite lost power in 1997, nine months after its launch. The second Scatterometer was launched in 1999, and its main functions include sending radar pulses to the ocean surface and measuring the ‘backscattered' or echoed radar pulses that bounce back to the satellite. When the scatterometer instrument - also called Seawinds - senses the ripples by winds near the ocean's surface, scientists are able to compute wind's speed and direction.Scatterometer circles Earth at an altitude of 800 kilometers (500 miles) once every 101 minutes, passing close to Earth's north and south poles.
Advanced Spaceborne Thermal Emission And Reflection Radiometer
As part of Nasa's Earth Observing System, ASTER is an imaging instrument flying on Terra satellite, with the aim to catch high-resolution global, regional and local images of Earth in 14 colour bands. Launched in late 1999, ASTER is a joint venture of US-Japan science team, and is quite useful when it comes to variety of land surface studies, courtesy its ability to serve as a zoom lens for other instruments.
Voyager 1 and 2
Mass: 2,100 kilograms (4,600 pounds) at launch; 825 kilograms (about 1,800 pounds) during mission.
One of the oldest space expeditions, Voyager 1 and 2 were first launched in 1977, and are expected to continue their research until 2020. The twin spacecrafts were rocketed into space in order to explore the three gaseous outer planets, Saturn, Uranus and Neptune. Within a span of 15 years, both managed to achieve their target, and were able to send valuable information regarding the atmosphere of the three planets. Finally, in August 1989, Voyager 2, flew by Neptune, which at that point was the farthest member of the solar system from the sun - Pluto once again became most distant in 1999. And almost a decade later, Voyager 1, passed the Pioneer 10 spacecraft to become the most distant human-made object in space.
Multi-Angle Imaging Spectroradiometre
InstrumentMass: 148 kilograms (326 pounds)OverviewA sophisticated imaging system like no other, MISR's unique point is its ability to collect images from nine widely spaced angles the satellite rides on glides above Earth. The different angled images captured by MISR have allowed scientists to study many different phenomena on Earth's surface and in its atmosphere, for example, developing three-dimensional models of the planet's surface and atmosphere. Like ASTER, MISR was also launched on Terra satellite in late 1999.
SpacecraftMass: 370 kilograms (814 pounds)OverviewA joint venture of Nasa and the European Space Agency, Ulysses was launched in 1990 with the aim to explore the heliosphere - the bubble in space blown out by the solar wind. It passed Jupiter in early 1992 and finally made its first pass of the Sun's south pole in 1994, and then another pass of the north pole in 1995. The next southern polar pass was made in 2000, and late last year Ulysses once again crossed into the Sun's south polar cap to track the sunspot cycle and the cycle of solar activity.Scientists hope that this exploration will help reveal the Sun's influence on space environment, and particularly on Earth. They are also monitoring the change in polarity of the Sun's magnetic field and its effect on the way cosmic ray particles reach the inner heliosphere.
Spacecraft:Mass: 5,712 kilograms (12,593 pounds), consisting of 2,125-kilogram (4,685-pound) orbiter, 320-kilogram (705-pound) Huygens probe, launch vehicle adapter and 3,132 kilograms (6,905 pounds) of propellants.Overview:Cassini is probably one of the most important and interesting ventures by Nasa, the European Space Agency and the Italian Space Agency, the three collaborators of the experiment. The spacecraft was sent in space in 1997 to study Saturn, for which on Cassini was Huygens, a scientific probe which was released from the main spacecraft to parachute through the atmosphere to the surface of Saturn and its largest moon, Titan.Around mid-2004 Cassini entered Saturn's orbit, and by early 2005 Huygens had dove into Titan's atmosphere. At present, the spacecraft is hovering in the ringed-planet's atmosphere only, sending back valuable images to unveil the mysteries of Saturnian system, studied by more than 250 scientists on daily basis.
Galaxy Evolution Explorer
OverviewGalaxy Evolution Explorer or GALEX was sent into space in 2003 in order to observe the million galaxies, and determine the distance of each galaxy from Earth and how fast stars are forming in each of them. Scientists believe that such information will help them understand when the existing stars and the chemical elements makeup our galaxy to form. The mission is also essential in understanding the evolution of the universe.GALEX's other goals included several first-of-a-kind sky surveys, like an extra-galactic (beyond our galaxy) ultraviolet all-sky survey.
2003 Mars Exploration Rovers
Spacecraft: Spirit and OpportunityMass: 180 kilogramsOverviewThe two rovers, Opportunity and Spirit have been scouring the Martian terrain for more than three years now. They landed on the red planet in early January, both rovers have been extremely vital in sending back information about Martian geology and atmosphere, courtesy the more than 100,000 spectacular full-colour images. These images have enabled scientist to study Mars deeper than what meets the telescopic eye. The rovers have been given different tasks to cover. While Spirit has managed to ‘unearth' variety of rocks on what has been named ‘Columbia Hills', discovering traces of water, Opportunity probed into a craters to reveal proof of past inter-dune playa lakes that evaporated to form sulfate-rich sands. Both rovers continue to explore the Martian land in search or further discoveries.
Wide Field And Planetary Camera 1 And 2
The main camera instrument on the Hubble Space Telescope, this 2.5-meter-diameter (8-foot) mirror collects light from extremely distant objects in deep space. The camera has played a vital role in discoveries in space by capturing sharp images, from its four internal camera systems: three wide-field cameras, and one narrow-field camera.
The first Wide Field/Planetary Camera was installed on the telescope in 1990. However, scientists soon discovered a small error in the curvature of the telescope's main mirror, which made it impossible to focus images sharply. The problem was solved and the next camera instrument, Wide Field/Planetary Camera 2, was installed on the telescope by spacewalking astronauts on a space shuttle mission three years after the initial launch.
Spitzer Space telescope
OverviewTermed as a cousin of Hubble telescope, Spitzer's main purpose is to study stars, galaxies and planetary discs. It was launched in 2003, and is the fourth and the final observatory under Nasa's Great Observatory Programme. Spitzer is also the first mission under Nasa's Origins programme, which seeks to answer the questions of our origin and whether we are alone in this Universe or not.This year, Spitzer, along with Hubble, discovered nine of the smallest, faintest and most compact galaxies ever observed in the distant Universe. These new galaxies are around a hundred to a thousand miles smaller than our Milky Way, and according to scientists, the stars in the galaxies are just a few million years old and are in the process of turning Big Bang elements (primarily hydrogen and helium) into heavier elements. This discovery will bring scientists closer in understanding the formative years of the Universe.
SpacecraftMass: 500 kg (1102 lbs)Overview:A joint mission of the US and France, Jason 1 is a follow up of Topex/Poseidon that measured oceanography from 1992-2005. It was launched in late 2001, with the aim to monitor global ocean circulation, to study the ties between the oceans and atmosphere and to improve global climate forecasts and predictions. Jason 1's findings have played an imperative role in understanding the relationship between Earth and ocean currents; observe sea-level changes and measure climate changes from close quarters. Jason 1 flew in tandem with Topex/ Poseidon until the latter spacecraft ceased operation.
Mass: 385 kilograms (848 pounds) total, consisting of 254-kilogram (560-pound) spacecraft and 46-kilogram (101-pound) sample return capsule, plus 85 kilograms (187 pounds) fuel.
The fourth Discovery mission - a programme to competitively select proposals for low-cost solar system exploration missions with highly focused science goals - Stardust was launched in early 1999 with the aim to bring back cometary material to the Earth. It was specially focused on a well-preserved comet called Wild-2 (pronounced as, ‘Vilt-2'), which makes the mission a pioneer in such expeditions.
In the spring of 2000, Stardust collected interstellar dust, and the next year it executed a flyby of Earth. In 2004, the spacecraft finally flew close to Wild-2, and collected particles for the analysis, which were then brought back by the sample return capsule in 2006. Scientists believe that Stardust's findings will reveal more about the composition of the building blocks of the early solar system and our neighbouring local stellar medium.
Presently, Stardust continues to orbit in space with the special focus on Wild-2.
The main pupose of Nasa's Deep Impact is to compare a comet surface with its coma and interior. It was done in mid-2005 when the spacecraft deployed an impactor which was essentially ‘run over' by the nucleus of comet Tempel 1. Travelling at a speed of 37,000 kms per hour, when the impactor crashed into the comet, the spacecraft was able to watch the 6.5-kilometre wide comet nucleus from nearby, and collected pictures and data. The study of the comet's nucleus helped in revealing the clues to early formation of solar system. Deep Impact's other findings of the comet are also of great importance to the scientific world. The spacecraft was launched into space in early 2005.
One of the most recent missions, CloudSat was launched into space in 2006. It is the first spacecraft to observe clouds on global basis, and its more important objective is to find data that could evaluate and improve the way clouds are represented in global models. These findings will help in better prediction of the clouds, and understanding of their relationship with the climate change.
Dawn was launched into the space in 2007 and is expected to complete its primary missions by 2015. Planning to cover 4.8 billion kms, Dawn's main purpose is to explore Vesta, one of the largest asteroids in the solar system, and the dwarf planet Ceres. Scientists believe that the study of these two bodies will help to compare the different evolutionary path each takes and provide an idea of the early solar system. They also hope that the data from the mission will bring significant breakthroughs in explaining how the solar system was formed.
Tropospheric Emission Spectrometre
TES, launched in 2004, and is aboard on Nasa's Aura spacecraft under the Earth's Observatory System programme. It has been designed to measure the state and composition of Earth's troposphere - the layer of the atmosphere that extends from Earth's surface to about 16-kilometres in altitude. The instrument's main purpose is to study ozone to give scientists the information about the location of ozone in troposphere, and how it interacts with other chemicals in the atmosphere. This will help scientists to better understand climate changes and issues like global warming, chemistry of polluted air, and ozone depletion in the stratosphere.
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