NASA’s Asteroid-Bound Spacecraft Aces Instrument Check

NASA - OSIRIS-REx Mission patch.

Sept. 26, 2016

Its science instruments have been powered on, and NASA’s OSIRIS-REx spacecraft continues on its journey to an asteroid. The spacecraft has passed its initial instrument check with flying colors as it speeds toward a 2018 rendezvous with the asteroid Bennu.

Last week NASA’s spacecraft designed to collect a sample of an asteroid ran the first check of its onboard instruments. Starting on Sept. 19, engineers controlling the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft powered on and operated the mission’s five science instruments and one of its navigational instruments. The data received from the checkout indicate that the spacecraft and its instruments are all healthy.

Image above: The first-light images of star fields from OCAMS’s MapCam and PolyCam illustrate each camera’s specialized function. MapCam’s medium resolution and wider field of view will help map the entire surface of Bennu in color. While PolyCam’s field of view is much smaller, it can see much fainter objects at a higher resolution. PolyCam’s ability to act as a telescopic will help the OSIRIS-REx team spot Bennu while it is still appears as a point of light against a field of stars. Image Credits: NASA/Goddard/University of Arizona.

Instrument testing commenced with the OSIRIS-REx Camera Suite (OCAMS), provided by the University of Arizona. On Monday, OCAMS executed its power-on and test sequence with no issues. The cameras recorded a star field in Taurus north of the constellation Orion along with Orion’s bright red star Betelgeuse. The three OCAMS cameras performed flawlessly during the test.

On Monday and Wednesday, the OSIRIS-REx Laser Altimeter (OLA), contributed by the Canadian Space Agency, conducted its test sequences, which included a firing of its laser.  All telemetry received from the OLA instrument was as expected.

On Tuesday, both the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS), provided by NASA’s Goddard Space Flight Center, and the OSIRIS-REx Thermal Emissions Spectrometer (OTES), provided by Arizona State University, were separately powered on for tests. Data from both during the checkout showed that the instruments were healthy. The science measurements acquired from OTES exceeded the instrument’s performance requirements.

Image above: On Sept. 19, the OCAMS MapCam camera recorded a star field in Taurus, north of the constellation Orion as part of the OSIRIS-REx spacecraft’s post-launch instrument check. MapCam's first color image is a composite of three of its four color filters, roughly corresponding to blue, green, and red wavelengths. The three images are processed to remove noise, co-registered, and enhanced to emphasize dimmer stars. Image Credits: NASA/Goddard/University of Arizona.

On Wednesday, the student experiment from MIT, the Regolith X-ray Imaging Spectrometer (REXIS), executed its functional test with no problems.  And on Thursday, the Touch and Go Camera System (TAGCAMS) navigational camera was powered on and tested, and it operated as expected.  As part of its checkout, TAGCAMS took an image of the spacecraft’s Sample Return Capsule.

The downlink of the test data continued through Sunday via the spacecraft’s low gain antenna (LGA), which transmitted at 40 kbps to NASA’s Deep Space Network.

Goddard Space Flight Center provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. Lockheed Martin Space Systems in Denver built the spacecraft and is providing spacecraft flight operations. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the agency’s New Frontiers Program for its Science Mission Directorate in Washington.

OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security Regolith Explorer): http://www.nasa.gov/mission_pages/osiris-rex/index.html

Images (mentioned), Text, Credits: NASA's Goddard Space Flight Center/Nancy Neal Jones/Karl Hille/University of Arizona/Erin Morton.

Greetings, Orbiter.ch

Hubble Spots Possible Water Plumes Erupting on Jupiter's Moon Europa

NASA - Hubble Space Telescope patch.

Sept. 26, 2016

Astronomers using NASA's Hubble Space Telescope have imaged what may be water vapor plumes erupting off the surface of Jupiter's moon Europa. This finding bolsters other Hubble observations suggesting the icy moon erupts with high altitude water vapor plumes.

The observation increases the possibility that missions to Europa may be able to sample Europa’s ocean without having to drill through miles of ice.

Image above: This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the features -- rising over 100 miles (160 kilometers) above Europa’s icy surface -- to be discerned. The water is believed to come from a subsurface ocean on Europa. The Hubble data were taken on January 26, 2014. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions. Image Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center.

“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”

The plumes are estimated to rise about 125 miles (200 kilometers) before, presumably, raining material back down onto Europa's surface. Europa has a huge global ocean containing twice as much water as Earth’s oceans, but it is protected by a layer of extremely cold and hard ice of unknown thickness. The plumes provide a tantalizing opportunity to gather samples originating from under the surface without having to land or drill through the ice.

The team, led by William Sparks of the Space Telescope Science Institute (STScI) in Baltimore observed these finger-like projections while viewing Europa's limb as the moon passed in front of Jupiter.

The original goal of the team's observing proposal was to determine whether Europa has a thin, extended atmosphere, or exosphere. Using the same observing method that detects atmospheres around planets orbiting other stars, the team realized if there was water vapor venting from Europa’s surface, this observation would be an excellent way to see it.

"The atmosphere of an extrasolar planet blocks some of the starlight that is behind it," Sparks explained. "If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette. And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter."

In 10 separate occurrences spanning 15 months, the team observed Europa passing in front of Jupiter. They saw what could be plumes erupting on three of these occasions.

Hubble Directly Images Possible Plumes on Europa

Video above: NASA's Hubble Space Telescope took direct ultraviolet images of the icy moon Europa transiting across the disk of Jupiter. Out of 10 observations, Hubble saw what may be water vapor plumes on three of the images. This adds another piece of supporting evidence to the existence of water vapor plumes on Europa; Hubble also detected spectroscopic signatures of water vapor in 2012. Video Credits: Goddard/Katrina Jackson.

This work provides supporting evidence for water plumes on Europa. In 2012, a team led by Lorenz Roth of the Southwest Research Institute in San Antonio, detected evidence of water vapor erupting from the frigid south polar region of Europa and reaching more than 100 miles (160 kilometers) into space. Although both teams used Hubble's Space Telescope Imaging Spectrograph instrument, each used a totally independent method to arrive at the same conclusion.

"When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it's pretty similar to what Roth and his team found," Sparks said. "The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work."

But as of yet, the two teams have not simultaneously detected the plumes using their independent techniques. Observations thus far have suggested the plumes could be highly variable, meaning that they may sporadically erupt for some time and then die down. For example, observations by Roth’s team within a week of one of the detections by Sparks’ team failed to detect any plumes.

If confirmed, Europa would be the second moon in the solar system known to have water vapor plumes. In 2005, NASA's Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn's moon Enceladus.

Scientists may use the infrared vision of NASA’s James Webb Space Telescope, which is scheduled to launch in 2018, to confirm venting or plume activity on Europa. NASA also is formulating a mission to Europa with a payload that could confirm the presence of plumes and study them from close range during multiple flybys.

“Hubble’s unique capabilities enabled it to capture these plumes, once again demonstrating Hubble’s ability to make observations it was never designed to make,” said Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington. “This observation opens up a world of possibilities, and we look forward to future missions -- such as the James Webb Space Telescope -- to follow up on this exciting discovery.”

The work by Sparks and his colleagues will be published in the Sept. 29 issue of the Astrophysical Journal.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (the European Space Agency.) NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. STScI, which is operated for NASA by the Association of Universities for Research in Astronomy in Washington, conducts Hubble science operations.

For images and more information about Europa and Hubble, visit:

http://www.nasa.gov/hubble
http://hubblesite.org/
https://www.spacetelescope.org/

Image (mentioned), Video (mentioned), Text, Credits: NASA/Sean Potter/Laurie Cantillo/Space Telescope Science Institute/Ann Jenkins/Ray Villard/Karen Northon.

Best regards, Orbiter.ch

The Incredible Shrinking Mercury is Active After All

NASA - MESSENGER Mission patch.

Sept. 26, 2016

It’s small, it’s hot, and it’s shrinking. New NASA-funded research suggests that Mercury is contracting even today, joining Earth as a tectonically active planet.

Images obtained by NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft reveal previously undetected small fault scarps— cliff-like landforms that resemble stair steps. These scarps are small enough that scientists believe they must be geologically young, which means Mercury is still contracting and that Earth is not the only tectonically active planet in our solar system, as previously thought.

The findings are reported in a paper in the October issue of Nature Geoscience.

“The young age of the small scarps means that Mercury joins Earth as a tectonically active planet, with new faults likely forming today as Mercury’s interior continues to cool and the planet contracts,” said lead author Tom Watters, Smithsonian senior scientist at the National Air and Space Museum in Washington, D.C.

Image above: It’s small, it’s hot, and it’s shrinking. Surprising new NASA-funded research suggests that Mercury is contracting even today, joining Earth as a tectonically active planet. Image Credits: NASA/JHUAPL/Carnegie Institution of Washington/USGS/Arizona State University.

Large fault scarps on Mercury were first discovered in the flybys of Mariner 10 in the mid-1970s and confirmed by MESSENGER, which found the planet closest to the sun was shrinking. The large scarps were formed as Mercury’s interior cooled, causing the planet to contract and the crust to break and thrust upward along faults making cliffs up to hundreds of miles long and some more than a mile (over one-and-a-half kilometers) high.

In the last 18 months of the MESSENGER mission, the spacecraft’s altitude was lowered, which allowed the surface of Mercury to be seen at much higher resolution. These low-altitude images revealed small fault scarps that are orders of magnitude smaller than the larger scarps. The small scarps had to be very young, investigators say, to survive the steady bombardment of meteoroids and comets. They are comparable in scale to small, young lunar scarps that are evidence Earth’s moon is also shrinking.

Image above: Small graben, or narrow linear troughs, have been found associated with small fault scarps (lower white arrows) on Mercury, and on Earth’s moon. The small troughs, only tens of meters wide (inset box and upper white arrows), likely resulted from the bending of the crust as it was uplifted, and must be very young to survive continuous meteoroid bombardment. Image Credits: NASA/JHUAPL/Carnegie Institution of Washington/Smithsonian Institution.

This active faulting is consistent with the recent finding that Mercury’s global magnetic field has existed for billions of years and with the slow cooling of Mercury’s still hot outer core.  It’s likely that the smallest of the terrestrial planets also experiences Mercury-quakes—something that may one day be confirmed by seismometers.

“This is why we explore,” said NASA Planetary Science Director Jim Green at Headquarters in Washington, D.C. “For years, scientists believed that Mercury’s tectonic activity was in the distant past. It’s exciting to consider that this small planet – not much larger than Earth’s moon – is active even today.”   

Managed by the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, MESSENGER launched Aug. 3, 2004 and began orbiting Mercury March 18, 2011. The mission ended with a planned impact on the surface of Mercury on April 30, 2015.

For more information about MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging), visit: http://www.nasa.gov/mission_pages/messenger/main/index.html

Images (mentioned), Text, Credits: NASA/ Bill Keeter.

Greetings, Orbiter.ch

Hidden Wonders

NASA & ESA - Cassini-Huygens Mission to Saturn & Titan patch.

Sept. 26, 2016

NASA's & ESA's Cassini spacecraft looks toward the brilliant disk of Saturn, surrounded by the icy lanes of its rings. Faint wisps of cloud are visible in the atmosphere. At bottom, ring shadows trace delicate, curving lines across the planet.

Prometheus (53 miles or 86 kilometers across) is just a few pixels wide in this view, barely visible as a dark speck in front of the planet, below the rings and to the left of center.

Between April and September 2017, Cassini will plunge repeatedly through the gap that separates the planet from the rings.

This view looks toward the sunlit side of the rings from about a degree above the ring plane. The image was taken in green light with the Cassini spacecraft wide-angle camera on July 21, 2016.

The view was obtained at a distance of approximately 529,000 miles (852,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 37 degrees. Image scale is 30 miles (50 kilometers) per pixel.                              

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org and ESA's website http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image, Text, Credits: NASA/JPL-Caltech/Space Science Institute/Tony Greicius.

Greetings, Orbiter.ch

Astrometry through the ages

ESA - Gaia Mission patch.

26 September 2016

Astrometry, the science of charting the sky, is one of the oldest branches of astronomy. Over the centuries, scientific and technological advancements have gradually improved the quality and information content of stellar catalogues.

Astrometry through the ages

This infographic illustrates qualitatively the progress in size and precision of measuring stellar positions and distances through the ages, featuring a series of landmarks in the history of astrometry, from ancient scientists to the space missions of our time.

The precision of stellar position measurements in the most ancient catalogues (top row) is represented with a blur around the stars, while the precision of the stellar distance measurements in the modern catalogues (bottom row) is conveyed with a linear ruler pointing towards the lower left corner of each frame – representing the location of Earth – and passing through each star. In the case of Gaia, ESA's state-of-the-art space mission currently charting over one billion stars (bottom right frame), the rulers are much smaller than the star symbols and thus not visible, to indicate the unparalleled precision of the mission.

The first documented records of systematic astronomical observations date back to the Assyro-Babylonians around 1000 BCE, and the oldest known stellar catalogue was compiled in the second century BCE by the Greek astronomer Hipparchus of Nicaea.

Hipparchus' catalogue (first frame, top row) lists the positions of 850 stars with a precision of less than one degree (one degree is twice the angular size of the full Moon) determined using only naked-eye observations and the few instruments available at the time: gnomons, astrolabes, and armillary spheres.

In the fifteenth century, Ulugh Beg of the Timurid dynasty constructed an enormous sextant with a radius of 36 metres in Samarkand, located in present-day Uzbekistan. Ruling over Central Asia, Ulugh Beg was also an astronomer and mathematician, and he compiled a catalogue of 994 stellar positions with a precision slightly better than that of Hipparchus (second frame, top row).

In the late sixteenth century, Danish astronomer Tycho Brahe measured the positions of about 1000 stars with a precision of about one arcminute, using large quadrants and sextants at the Uraniborg observatory on the island of Hven (in present-day Sweden). His catalogue (third frame, top row) was completed in 1598 and published in 1627.

In 1725, English astronomer John Flamsteed published the first stellar catalogue (fourth frame, top row) compiled with the aid of a telescope, listing the positions of almost 3000 stars with a precision of 10-20 arcseconds. French astronomer Jérôme Lalande published an even greater catalogue (fifth frame, top row) with the position of 50 000 stars and a precision of around three arcseconds, in 1801.

Not so long after that, in 1838, German astronomer Friedrich Bessel was the first to publish a reliable measurement of parallax, the yearly displacement of a star's position due to Earth's revolution around the Sun. Bessel's measurement for the star 61 Cygni amounted to 0.314 arcseconds, placing the star at a distance of about 10 light-years.

Bessel used a special type of telescope, the heliometer, originally developed to observe the Sun and consisting of a lens cut in half. Two more astronomers, the German Wilhelm Struve and the British Thomas Henderson, also successfully measured parallaxes in the late 1830s. While not strictly a catalogue, these three were the first measurements of stellar distances in the history of astronomy (first frame, bottom row).

From the 1850s onwards, the application of photography to astrometry transformed the practice of charting the sky. Compiling many photographic observations, Dutch astronomer Jacobus Kapteyn started measuring the parallax of a few hundreds of stars in the early 1900s (second frame, bottom row).

In 1924, American astronomer Frank Schlesinger made huge progress in the use of photographic plates to measure parallaxes and published a catalogue with the parallaxes of almost 2000 stars, probing stellar distances out to a few dozen light-years from Earth. His catalogue was extended to about 6000 stars by Louise Freeland Jenkins in 1952, and to over 8000 stars by William van Altena in 1995 (third frame, bottom row), but the flickering effect caused by Earth's atmosphere and the distortion of the telescopes caused by Earth's gravity prevented astronomers from reaching a precision better than about 0.01 arcseconds.

The onset of the space age brought astrometry firmly back to centre stage in astronomy. ESA's Hipparcos mission, operating from 1989 to 1993, was the first space telescope devoted to measuring stellar positions.

The Hipparcos catalogue, released in 1997, contains the position, parallax and proper motion of 117 955 stars with a precision of 0.001 arcseconds, allowing astronomers to probe stellar distances out to over 300 light-years (fourth frame, bottom row).

https://soundcloud.com/esa/from-hipparchus-to-hipparcos-a-sonification-of-stellar-catalogues

The Gaia mission is building on the legacy of Hipparcos to chart one billion stars – about one per cent of the content of our Galaxy. Eventually, it will measure positions and parallaxes with astrometric precisions down to 0.00001 arcseconds for the brightest stars observed (fifth frame, bottom row).

Read more in the History of Astrometry series: http://sci.esa.int/gaia/history-of-astrometry

ESA's Gaia mission recently released its first batch of data, based on observations obtained with the satellite during its first 14 months of science operations. This ambitious mission is the culmination of over two thousand years of astrometry – the science of charting the sky. A new sonification demonstrates in a novel way the remarkable progress that has been made in the lead up to the first data release from Gaia. Related article:

From Hipparchus to Hipparcos: A sonification of stellar catalogues
http://sci.esa.int/gaia/58311-from-hipparchus-to-hipparcos-a-sonification-of-stellar-catalogues/

Related links:
Gaia: http://www.esa.int/Our_Activities/Space_Science/Gaia

Gaia overview: http://www.esa.int/Our_Activities/Space_Science/Gaia/Gaia_overview

Gaia factsheet: http://www.esa.int/Our_Activities/Space_Science/Gaia/Gaia_factsheet

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Gaia/Frequently_Asked_Questions_about_Gaia

Gaia brochure: http://www.esa.int/About_Us/ESA_Publications/ESA_BR-296_Gaia_ESA_s_galactic_census

Image, Text, Credit: European Space Agency (ESA).

Greetings, Orbiter.ch

FAST - The World largest radiotelescope in service

FAST - Five-hundred-meter Aperture Spherical Telescope logo.

September 25, 2016

Image above: The installation of the world's largest radio telescope, Five-hundred-meter Aperture Spherical Telescope (FAST), is completed in Guizhou, China, on July 3, 2016. Image Credit: Xinhua.

The largest radio telescope in the world became operational Sunday (Today) in the southwest of China. The enormous tool is part of a huge project which aims according to Beijing detect extraterrestrial intelligent life.

Building the world's largest radio telescope - BBC News

Called by scientists "Five-hundred-meter Aperture Spherical Radio Telescope (FAST)", the telescope began operating around midday, said Xinhua news agency. FAST, which has a spherical aperture with a diameter of 500 meters, covering an area equivalent to 30 football fields, is located in a rural area of Guizhou province (southwest), three karst hills.

Finding intelligent life

The plant, whose construction began in March 2011, has cost 1.2 billion yuan (180 million francs) and significantly exceeds in size the Arecibo radio telescope, located in the island of Puerto Rico, which has a diameter 305 meters.

Image above: Largest ever in the world, the Chinese five hundred meter Aperture Spherical Telescope (FAST) is about to complete, now we can wait for the aliens. Image Credit: Xinhua.

The Director General of the Chinese Astronomical Society, Wu Xiangping, said last year in New China that the high degree of sensitivity FAST would "help search of intelligent life outside our galaxy."

Related article:

China FAST hunt for alien life with giant telescope
http://orbiterchspacenews.blogspot.ch/2016/07/china-fast-hunt-for-alien-life-with.html

For more information about Five-hundred-meter Aperture Spherical Telescope (FAST), visit: http://fast.bao.ac.cn/en/

Images (mentioned), Video (mentioned), Text, Credits: CDN/Xinhua/WikiMedia Commons/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

Voyager Golden Record ready to land on Earth

NASA - Voyager 1 & 2 Mission patch.

September 25, 2016

In the USA, an initiative aimed at making available to earthlings the Golden Record, Album designed for extraterrestrials.

In 2017, it will make 40 years that NASA has sent probes Voyager 1 and 2, on which hung the Golden Record, explore the outer solar system. In view of this anniversary, a label of San Francisco launched a crowdfunding campaign on Kickstarter to publish on vinyl sound substance of the famous disc 12-inch gold-plated.

Image above: The Golden Record aboard Voyager 1 and 2. Image Credit: NASA.

The project will become reality if backed up to 200,000 francs. before 21 October 2016. This is the case because in 48 hours, Internet users have already promised 330,000 francs. If the interest is huge, it is that there is at present on our planet no copy of the cake sent into space to present the Earth to aliens. Even the famous astrophysicist Carl Sagan had not obtained copy, while he was yet in the scientific head of the team responsible for defining its content.

Artist's view of the Voyager probe. Image Credit: NASA

To recall, in the furrows of the Golden Record included among other images of our planet (which will be the subject of a book), various sounds from wind noise to the cries of animals, greetings in 55 languages and 90 minutes of music. Among the titles sent into the cosmos include "Johnny B. Goode" by Chuck Berry, "Melancholy Blues" of Louis Armstrong and works by Bach, Mozart and Beethoven.

Chuck Berry - Johnny B. Goode

The track, of course, comes from the famous Golden Record, a copy of which is aboard each of two of NASA's most famous spacecraft. Back in the summer of 1977, the space agency launched Voyager 1 and 2 toward Jupiter and Saturn to explore those worlds up-close for the first time. But the space probes didn't stick around; they kept going and going.

On the off-chance that either of the robots might encounter a sentient alien race, scientists pre-loaded two 12-inch gold-plated phonograph records with grainy sounds and images reminiscent of our diverse and vibrant life here on Earth. Then they attached one record to each spacecraft before launching them: http://voyager.jpl.nasa.gov/spacecraft/goldenrec.html

For the first time, NASA has strung together each of the nearly 20 individual sounds of Earth into one beautiful yet eerie track, which the space agency just released to SoundCloud for your listening pleasure: https://soundcloud.com/nasa/sets/golden-record-sounds-of

Graphics above: NASA left instructions on each of the Voyager's golden records for extraterrestrial life to enjoy. Graphics Credit: NASA.

NASA meant for the recordings to serve as an auditory and visual time capsule of sorts — and a sleeker, updated take on a six-by-nine-inch golden plaque launched with each of the Pioneer 10 and 11 spacecraft. Those plaques were engraved with a naked man and woman gesturing goodwill, then bolted to the outside of each spacecraft's frame:

Image above: Pioneer 10 and 11, launched in 1972, were the first spacecraft to leave our solar system. Image Credits: NASA/WikiMedia Commons.

The contents of the record were selected for NASA by a committee chaired by Carl Sagan of Cornell University, et. al. Dr. Sagan and his associates assembled 115 images and a variety of natural sounds, such as those made by surf, wind and thunder, birds, whales, and other animals.

Artist's view of the Pioneer probe. Image Credits: NASA/WikiMedia Commons

To this they added musical selections from different cultures and eras, and spoken greetings from Earth-people in fifty-five languages, and printed messages from President Carter and U.N. Secretary General Waldheim. Each record is encased in a protective aluminum jacket, together with a cartridge and a needle. Instructions, in symbolic language, explain the origin of the spacecraft and indicate how the record is to be played.

Voyager Golden Record Explained

The definitive work about the Voyager record is "Murmurs of Earth" by Executive Director, Carl Sagan, Technical Director, Frank Drake, Creative Director, Ann Druyan, Producer, Timothy Ferris, Designer, Jon Lomberg, and Greetings Organizer, Linda Salzman. Basically, this book is the story behind the creation of the record, and includes a full list of everything on the record. "Murmurs of Earth", originally published in 1978, was reissued in 1992 by Warner News Media with a CD-ROM that replicates the Voyager record. Unfortunately, this book is now out of print, but it is worth the effort to try and find a used copy or browse through a library copy.

Related links:

Pioneer 10 and 11: http://www.nasa.gov/centers/ames/missions/archive/pioneer10-11.html

Voyager 1 & 2: http://voyager.jpl.nasa.gov/

Images (mentioned), Videos, Text, Credits: NASA/Wikipedia/Jhon Lomberg/YouTube/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch