Space Exploration Chronology: 1990-1999 | Magellan Venus | gjlHubble Telescope | First Exoplanet | Mars Pathfinder | Mir Space Station

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April 1990

NASA, ESA launch The Hubble Telescope

Credit: Courtesy of NASA/

Mission launched April 24, 1990
Destination reached April 24, 1990
Objectives Conduct observations of Cosmos using Wide Field and Planetary Camera, Goddard High Resolution Spectrograph, High Speed Photometer, Faint Object Camera, and Faint Object Spectrograph.
Results Overall, scientific work, that resulted from the Hubble Telescope, exceeded expectations. It established the rate of the expansion of the Universe more accurately than ever before. Allowed to establish the age of the Universe more precisely. Found that the expansion of the Universe was accelerating, rather than decelerating as was previously thought. Helped to better understand Dark Energy and Dark Matter, though still not conclusively nor entirely. Proved Black Holes to be real beyond doubt, they were also found to be present in center of virtually every galaxy. The Hubble established an intricate relationship between Galaxies and their Black Holes. Expanded our understand of gamma ray bursts. Found first evidence of extrasolar (beyond our Solar System) planets, later confirmed a number of extrasolar planets and provided us with fascinating information regarding their composition and dynamics. Obtained images of galaxies billions of years away, providing humanity with a glimpse into the cosmic past. Provided useful experience in terms of conducting complex repairs in orbit, a total of five such missions were undertaken using the Shuttle.

The Hubble Telescope became a legend over the course of its over two decades of existence. It was built to be repaired in space by astronauts, which was done five times, in an unprecedented complexity. The story of the Hubble is that of extreme difficulties and extraordinary success. It was planned as early as late 1960's, funded in the late 1970's with its launch continuously postponed from 1983 until 1989. After it was launched, it became immediately obvious that it had an inverted vital mirror which was fixed in 1993. Despite these shortcomings, Hubble proved to be a source of immense scientific data. The high cost of the entire Hubble Telescope project has always been controversial. However, thousands of scientific papers have been published based on data gathered by the telescope, significantly advancing the science of Astronomy.

Among its successes, The Hubble Telescope invigorated public interest in science and space exploration specifically, with its high resolution images of the worlds billions of light years away.

For more information visit the official NASA Hubble web-site by clicking on this text

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August 1990

Magellan probe arrives at Venus, begins radar mapping of the planet

Image courtesy of NASA
Click on the image to enlarge it

Mission launched May 4, 1989
Destination reached August 10, 1990
Objectives The Magellan mission studied land forms and tectonics, impact processes, erosion, deposition, chemical processes, and model the interior of Venus. Specific objectives were:

(1) obtain near-global radar images of Venus' surface with a resolution equivalent to optical imaging of 1 km per line pair;
(2) obtain a near-global topographic map with 50 km spatial and 100 m vertical resolution;
(3) obtain near-global gravity field data with 700 km resolution and 2--3 milligals (1 gal = 1 cm/s**2) accuracy; and,
(4) develop an understanding of the geological structure of the planet, including its density distribution and dynamics.(2)
Results Magellan imaged 98% of the total surface and showed us an Earth-sized planet with no evidence of Earth-like plate tectonics. At least 85% of the surface is covered with volcanic flows, the remainder by highly deformed mountain belts. Even with the high surface temperature (475 C) and high atmospheric pressure (92 bars), the complete lack of water makes erosion a negligibly slow process, and surface features can persist for hundreds of millions of years. Some surface modification in the form of wind streaks was observed. Over 80% of Venus lies within 1 km of the mean radius of 6051.84 km.

The mean surface age is estimated to be about 500 million years. A major unanswered question concerns whether the entire surface was covered in a series of large events 500 million years ago, or if it has been covered slowly over time. The gravity field of Venus is highly correlated with the surface topography, which indicates the mechanism of topographic support is unlike the Earth, and may be controlled by processes deep in the interior. Details of the global tectonics on Venus are still unresolved.(3)

Megallan chronology:

04 May 1989 - Launch
10 Aug 1990 - Venus orbit insertion and spacecraft checkout
15 Sep 1990 - Cycle 1: Radar mapping (left-looking)
15 May 1991 - Cycle 2: Radar mapping (right-looking)
15 Jan 1992 - Cycle 3: Radar mapping (left-looking)
14 Sep 1992 - Cycle 4: Gravity data acquisition
24 May 1993 - Aerobraking to circular orbit
03 Aug 1993 - Cycle 5: Gravity data acquisition
30 Aug 1994 - Windmill experiment
12 Oct 1994 - Termination experiment - loss of signal
13 Oct 1994 - Presumed loss of spacecraft

To read detailed account of cycles click here

Much of the NASA funding was directed at the Space Shuttle program for over a decade, resulting in no interplanetary scientific missions. Magellan was the first such mission since Pioneer Venus probes of 1978, which left many questions unanswered. It was the first interplanetary probe to be launched from the Space Shuttle.

Courtesy of NASA/
Color-coded hemispheric view of Venus to represent elevation
Click on the image to see in full resolution

As a result of Magellan's radar mapping, 98% of Venusian topographic terrain has been obtained and a computer generated 3D model produced. Venus is found to have a geologically young surface, thousands of kilometers long lava channels and lack of plate tectonics. The latter requires further investigation to be confirmed.

Courtesy of NASA/
Click on the image to see in full resolution
A portion of western Eistla Regio represented in a three-dimensional computer view of the surface using Magellan's data

Click on this link for more information about Magellan space probe

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A planet outside our Solar System is detected & confirmed, for the first time

Artist's rendering
Credit: Tyrogthekreeper, at
Click on the image to see in full resolution

Astronomers Aleksander Wolszczan and Dale Frail discovered first confirmed exoplanet. People had assumed and speculated about the existence of planets outside our Solar System before, but this discovery launched a massive, international hunt for extra solar planets, also known as exoplanets. In the beginning of the 21st century this search transformed into a more ambitious paradigm: search for Earth-like planets, first of which was discovered in 2010.

In 1992, astronomers had discovered two planets, orbiting around a Pulsar-type of star, located 980 light years away from Sol (our sun). The first planet is called PSR B1257+12 B, it is four time larger than Europe. Both planets are believed to be of chthonian class, which means that they are former Gas Giants, whose atmosphere was stripped due to extreme proximity to a star. These planets are regarded as deadly for life as we know it.

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Soviet-Russian space station Mir is completed

Completed Mir space station in 1996, picture taken from NASA Space Shuttle Atlantis
Credit: Courtesy of NASA/
Click on the image to see in full resolution

First module launched February 19, 1986
Space Station completed April 26, 1996
Objectives Launch and assemble in space six modules; Mir core module, Kvant-1, Kvant-2, Kristall, Spektr and Priroda. Mir was to operate in low Earth orbit as a scientific laboratory, in a unique microgravitational environment, continuing the legacy of the Soviet Salyut space stations. Crew would conduct experiments primarily in biology, human biology, astrophysics, astronomy, Earth meteorology and prepare for the future colonization of outer space.
Results The last crew visited Mir in 2000, for repair works. The space station broke numerous space-related records, which were later surpassed by the International Space Station. Launching of the post-soviet (1991) modules was greatly delayed, as Mir was transferred from the collapsed Soviet Union to the Russian Federation. In 1992 NASA became intrically involved in what became known as the Shuttle-Mir programme. In 1995 an American Docking Module was installed for easier access via the Space Shuttle. Russian, American and other astronauts from around the world worked onboard the Mir space station. The success of international cooperation on Mir served as foundation for the International Space Station.

Total of 28 long-duration crews inhabited Mir space station. 39 manned spaceflights to Mir were conducted. Despite constant need of repairs and a total cost of $4.3 Billion, Mir is regarded as a huge success in manned exploration of outer space. Following Mir, most manned activities in space involve international cooperation, which was not the case during the Cold War.

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NASA's Pathfinder lands on Mars

Click on the image to enlarge
Credit: Courtesy of NASA/

Mission launched December 4, 1996
Destination reached July 4, 1997
Objectives Proving feasibility of new landing technology and low cost approach for extensive, scientific exploration of Mars, becoming a trailblazer for future rover missions. Collect scientific data regarding meteorological conditions on the surface. Analyze rocks and soil samples. Study evolution of Martian geology.
Results Evidence found supporting ancient wet climate theory, including seemingly sedimentary rocks and highly magnetic dust. However, there was no evident erosion for billions of years, suggesting that it has been in its present condition for at least 1.8 billions of years. Crust found to have similar composition with that of Earth. Surface soil found to be generally uniform in its composition around the globe, partially due to the so called Dust Devils. The planet is found to have a central metallic core with a radius between 1,300 and 2,400 kilometers. New spacecraft delivery technology and technique successfully exercised.

Mars Pathfinder marked a new era in exploration of Mars on an unprecedented scale. It was the first major spacecraft to land on Mars and conduct scientific research since the famous Viking missions of 1976. Mars Pathfinder was a pioneer in several ways. It was part of new NASA dedication to launching relatively cheap missions in relatively small periods of time. The mission included the first successful rover to ever reach another planet and became a first in a series of successful missions in the beginning of the 21st century.

The rover, named Sojourner, employed first sophisticated use of Artificial Intelligence to automatically avoid obstacles on the Martian surface. This technology was later improved upon for use by future NASA rovers. The landing procedure utilized a new, innovative approach using airbags for a safe touchdown.*

Click on the image to enlarge it
Credit: Courtesy of NASA/

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  1. NASA archives
  2. National Space Science Center: Megallen, NSSDC ID: 1989-033B
  3. National Space Science Center: Magellan Mission to Venus
  4. List item 4 All Rights Reserved