NASA
Mariner 2 was the first successful interplanetary spacecraft. It flew past Venus in 1962.
updated 12/14/2012 2:49:35 PM ET 2012-12-14T19:49:35

Fifty years ago Friday, NASA's Mariner 2 spacecraft made its closest approach to the planet Venus, marking the first-ever flyby of another planet.

Mariner 2 zoomed to within 21,564 miles (34,675 kilometers) of Venus on Dec. 14, 1962, gathering a trove of data about Earth's hellishly hot sister planet. The probe took the first close-up measurements of Venus' scorching temperatures, for example, helping confirm scientists' suspicions that a runaway greenhouse effect had taken hold of the world.

Tracking Mariner 2's radio signals, researchers also calculated Venus' mass with unprecedented precision, NASA officials said.

The spacecraft's flyby also marked a proud moment for NASA and the United States, after a five-year stretch in which the Soviet Union had claimed all of the world's big space firsts. The Soviets successfully launched the first artificial satellite in 1957, sent a probe to the moon in 1959 and put the first human in space in 1961. [Video: Mariner 2's Venus Flyby]

"JPL has always attempted to do mighty things on behalf of NASA and our nation," Charles Elachi, director of NASA's Jet Propulsion Laboratory in Pasadena, Calif., which managed Mariner 2's mission, said in a statement. "Achieving America's first 'first in space' is among the lab's proudest achievements."

Mariner 2 had a bumpy ride. Shortly after launch on Aug. 27, 1962, an electrical short caused the probe's rocket to roll, rendering it unresponsive to guidance commands. But the short circuit mysteriously healed itself about a minute later, NASA officials said.

Things got dicey during Mariner 2's cruise to Venus, too. A solar panel on the spacecraft stopped working on two separate occasions, and attitude-controlling gyroscopes misbehaved.

Further, the probe's temperature rose dramatically as it approached Venus, causing managers to worry that Mariner 2 might be cooked before it could complete its mission.

But Mariner 2 overcame all of this, and the rest is history.

In addition to lifting Venus' veil, the spacecraft's observations also confirmed the existence of the solar wind and enabled scientists to refine the value of the astronomical unit — the distance from Earth to the sun, which is about 93 million miles (150 million km).

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In the half-century after Mariner 2's close encounter, other spacecraft have further studied the second planet from the sun. The Soviet Union even landed a number of probes on Venus' surface, beginning with Venera 7 in 1970. But Mariner 2 will always have a special place in history.

"There will be other missions to Venus, but there will never be another first mission to Venus," Jack James of JPL, Mariner 2's project manager, said before his death in 2001.

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Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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