NASA's Juno Mission Halfway to Jupiter Science

NASA - JUNO Mission logo.

Dec. 12, 2018

Image above: A south tropical disturbance has just passed Jupiter's iconic Great Red Spot and is captured stealing threads of orange haze from the Great Red Spot in this series of color-enhanced images from NASA's Juno spacecraft. From left to right, this sequence of images was taken between 2:57 a.m. and 3:36 a.m. PDT (5:57 a.m. and 6:36 a.m. EDT) on April 1, 2018, as the spacecraft performed its 12th close flyby of Jupiter. Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran.

Fly-Around of Jupiter by NASA's Juno Spacecraft

Video Credits: NASA/JPL-Caltech/SwRI/MSSS/JunoCam.

On Dec. 21, at 8:49:48 a.m. PST (11:49:48 a.m. EST) NASA's Juno spacecraft will be 3,140 miles (5,053 kilometers) above Jupiter's cloud tops and hurtling by at a healthy clip of 128,802 mph (207,287 kilometers per hour). This will be the 16th science pass of the gas giant and will mark the solar-powered spacecraft's halfway point in data collection during its prime mission.

Image above: This mosaic combines color-enhanced images taken over Jupiter's north pole when the lighting was excellent for detecting high bands of haze. The images were taken in the final hours of Juno's perijove 12 approach on April 1, 2018. Citizen scientists Gerald Eichstädt and John Rogers created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/John Rogers.

Juno is in a highly-elliptical 53-day orbit around Jupiter. Each orbit includes a close passage over the planet's cloud deck, where it flies a ground track that extends from Jupiter's north pole to its south pole.

Image above: Detailed structure in the clouds of Jupiter's South Equatorial Belt brown barge is visible in this color-enhanced image taken at 10:28 p.m. PDT on July 15, 2018 (1:28 a.m. EDT on July 16), as the spacecraft performed its 14th close flyby of the gas giant planet. Citizen scientist Kevin M. Gill created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.

"With our 16th science flyby, we will have complete global coverage of Jupiter, albeit at coarse resolution, with polar passes separated by 22.5 degrees of longitude," said Jack Connerney, Juno deputy principal investigator from the Space Research Corporation in Annapolis, Maryland. "Over the second half of our prime mission — science flybys 17 through 32 — we will split the difference, flying exactly halfway between each previous orbit. This will provide coverage of the planet every 11.25 degrees of longitude, providing a more detailed picture of what makes the whole of Jupiter tick."

Image above: A "brown barge" in Jupiter's South Equatorial Belt is captured in this color-enhanced image from NASA's Juno spacecraft. This color-enhanced image was taken at 10:28 p.m. PDT on July 15, 2018 (1:28 a.m. EDT on July 16), as the spacecraft performed its 14th close flyby of Jupiter. Citizen scientist Joaquin Camarena created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Joaquin Camarena.

Launched on Aug. 5, 2011, from Cape Canaveral, Florida, the spacecraft entered orbit around Jupiter on July 4, 2016. Its science collection began in earnest on the Aug. 27, 2016, flyby. During these flybys, Juno's suite of sensitive science instruments probes beneath the planet's obscuring cloud cover and studies Jupiter's auroras to learn more about the planet's origins, interior structure, atmosphere and magnetosphere.

Image above: A long, brown oval known as a "brown barge" in Jupiter's North North Equatorial Belt is captured in this color-enhanced image from NASA's Juno spacecraft. This image was taken at 6:01 p.m. PDT (9:01 p.m. EDT) on Sept. 6, 2018, as the spacecraft performed its 15th close flyby of Jupiter. Citizen scientist Kevin M. Gill created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.

"We have already rewritten the textbooks on how Jupiter's atmosphere works, and on the complexity and asymmetry of its magnetic field," said Scott Bolton, principal investigator of Juno, from the Southwest Research Institute in San Antonio. "The second half should provide the detail that we can use to refine our understanding of the depth of Jupiter's zonal winds, the generation of its magnetic field, and the structure and evolution of its interior."

Image above: This Earth-based observation of Jupiter and the South Tropical Disturbance approaching the Great Red Spot was captured on Jan. 26, 2018. Amateur astronomer Christopher Go took and processed this image. Image Credits: Christopher Go.

Two instruments aboard Juno, the Stellar Reference Unit and JunoCam, have proven to be useful not only for their intended purposes, but also for science data collection. The Stellar Reference Unit (SRU) was designed to collect engineering data used for navigation and attitude determination, so the scientists were pleased to find that it has scientific uses as well.

Image above: A multitude of bright white "pop-up" storms in this Jupiter cloudscape appear in this image from NASA's Juno spacecraft. This color-enhanced image was taken at 1:55 p.m. PDT (4:55 p.m. EDT) on Oct. 29, 2018, as the spacecraft performed its 16th close flyby of Jupiter. Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran.

"We always knew the SRU had a vital engineering job to do for Juno," said Heidi Becker, Juno's radiation monitoring investigation lead at NASA's Jet Propulsion Laboratory in Pasadena, California. "But after making scientific discoveries in Jupiter's radiation belts and taking a first-of-its-kind image of Jupiter's ring, we realized the added value of the data. There is serious scientific interest in what the SRU can tell us about Jupiter."

Image above: This image was taken at 7:21 p.m. PDT (10:21 p.m. EDT) on Sept. 6, 2018, as the spacecraft performed its 15th close flyby of Jupiter. The version of the image on the left side shows Jupiter in approximate true color, while the same image on the right has been processed to bring out detail close to the terminator and reveals four of the five southern circumpolar cyclones plus the cyclone in the center. Citizen scientist Björn Jónsson created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Björn Jónsson.

The JunoCam imager was conceived as an outreach instrument to bring the excitement and beauty of Jupiter exploration to the public.

 Juno spacecraft orbiting Jupiter. Animation Credit: NASA

"While originally envisioned solely as an outreach instrument to help tell the Juno story, JunoCam has become much more than that," said Candy Hansen, Juno co-investigator at the Planetary Science Institute in Tucson, Arizona. "Our time-lapse sequences of images over the poles allow us to study the dynamics of Jupiter's unique circumpolar cyclones and to image high-altitude hazes. We are also using JunoCam to study the structure of the Great Red Spot and its interaction with its surroundings."

The SRU and JunoCam teams both now have several peer-reviewed science papers —either published or in the works — to their credit.

Image above: Jupiter's northern circumpolar cyclones are captured in this color-enhanced image from NASA's Juno spacecraft. The image was taken at 5:42 p.m. PDT (8:42 p.m. EDT) on Sept. 6, 2018, as the spacecraft performed its 15th close flyby of Jupiter. Citizen scientist Gerald Eichstädt created this image using data from the spacecraft's JunoCam imager. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt.

NASA's JPL manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers Program, which is managed at NASA's Marshall Space Flight Center in Huntsville, Alabama, for NASA's Science Mission Directorate. The Italian Space Agency (ASI) contributed two instruments, a Ka-band frequency translator (KaT) and the Jovian Infrared Auroral Mapper (JIRAM). Lockheed Martin Space in Denver built the spacecraft.

More information about Juno is available at: https://www.nasa.gov/juno and https://www.missionjuno.swri.edu

More information on Jupiter is at: https://www.nasa.gov/jupiter

Images (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Dwayne Brown/JoAnna Wendel/Tony Greicius/JPL/DC Agle.

Greetings, Orbiter.ch

Dancing with the Enemy

ESO - European Southern Observatory logo.

12 December 2018

ESO’s R Aquarii Week continues with the sharpest R Aquarii image ever

R Aquarii peculiar stellar relationship captured by SPHERE

While testing a new subsystem on the SPHERE planet-hunting instrument on ESO’s Very Large Telescope, astronomers were able to capture dramatic details of the turbulent stellar relationship in the binary star R Aquarii with unprecedented clarity — even compared to observations from Hubble.

R Aquarii viewed by the Very Large Telescope and Hubble

This spectacular image — the second instalment in ESO’s R Aquarii Week — shows intimate details of the dramatic stellar duo making up the binary star R Aquarii. Though most binary stars are bound in a graceful waltz by gravity, the relationship between the stars of R Aquarii is far less serene. Despite its diminutive size, the smaller of the two stars in this pair is steadily stripping material from its dying companion — a red giant.

R Aquarii In the constellation Aquarius

Years of observation have uncovered the peculiar story behind the binary star R Aquarii, visible at the heart of this image. The larger of the two stars, the red giant, is a type of star known as a Mira variable. At the end of their life, these stars start to pulsate, becoming 1000 times as bright as the Sun as their outer envelopes expand and are cast into the interstellar void.

Digitized Sky Survey image around R Aquarii

The death throes of this vast star are already dramatic, but the influence of the companion white dwarf star transforms this intriguing astronomical situation into a sinister cosmic spectacle. The white dwarf — which is smaller, denser and much hotter than the red giant — is flaying material from the outer layers of its larger companion. The jets of stellar material cast off by this dying giant and white dwarf pair can be seen here spewing outwards from R Aquarii.

Zooming in on R Aquarii

Occasionally, enough material collects on the surface of the white dwarf to trigger a thermonuclear nova explosion, a titanic event which throws a vast amount of material into space. The remnants of past nova events can be seen in the tenuous nebula of gas radiating from R Aquarii in this image.

The ever-changing R Aquarii

R Aquarii lies only 650 light-years from Earth — a near neighbour in astronomical terms — and is one of the closest symbiotic binary stars to Earth. As such, this intriguing binary has received particular attention from astronomers for decades. Capturing an image of the myriad features of R Aquarii was a perfect way for astronomers to test the capabilities of the Zurich IMaging POLarimeter (ZIMPOL), a component on board the planet-hunting instrument SPHERE. The results exceeded observations from space — the image shown here is even sharper than observations from the famous NASA/ESA Hubble Space Telescope.

A vampiric star

SPHERE was developed over years of studies and construction to focus on one of the most challenging and exciting areas of astronomy: the search for exoplanets. By using a state-of-the-art adaptive optics system and specialised instruments such as ZIMPOL, SPHERE can achieve the challenging feat of directly imaging exoplanets. However, SPHERE’s capabilities are not limited to hunting for elusive exoplanets. The instrument can also be used to study a variety of astronomical sources — as can be seen from this spellbinding image of the stellar peculiarities of R Aquarii.

Close-up of a red giant star

Jet outburst of a vampiric star

Changing brightness of R Aquarii

Close-up of jets

More information:

This research was presented in the paper “SPHERE / ZIMPOL observations of the symbiotic system R Aqr. I. Imaging of the stellar binary and the innermost jet clouds” by H.M. Schmid et. al, which was published in the journal Astronomy & Astrophysics.

The team was composed of H. M. Schmid (ETH Zurich, Institute for Astronomy, Switzerland), A. Bazzon (ETH Zurich, Institute for Astronomy, Switzerland), J. Milli (European Southern Observatory), R. Roelfsema (NOVA Optical Infrared Instrumentation Group at ASTRON, the Netherlands), N. Engler (ETH Zurich, Institute for Astronomy, Switzerland) , D. Mouillet (Université Grenoble Alpes and CNRS, France), E. Lagadec (Université Côte d’Azur, France), E. Sissa (INAF and Dipartimento di Fisica e Astronomia “G. Galilei” Universitá di Padova, Italy), J.-F. Sauvage (Aix Marseille Univ, France), C. Ginski (Leiden Observatory and Anton Pannekoek Astronomical Institute, the Netherlands), A. Baruffolo (INAF), J.L. Beuzit (Université Grenoble Alpes and CNRS, France), A. Boccaletti (LESIA, Observatoire de Paris, France), A. J. Bohn (ETH Zurich, Institute for Astronomy, Switzerland), R. Claudi (INAF, Italy), A. Costille (Aix Marseille Univ, France), S. Desidera (INAF, Italy), K. Dohlen (Aix Marseille Univ, France), C. Dominik (Anton Pannekoek Astronomical Institute, the Netherlands), M. Feldt (Max-Planck-Institut für Astronomie, Germany), T. Fusco (ONERA, France), D. Gisler (Kiepenheuer-Institut für Sonnenphysik, Germany), J.H. Girard (European Southern Observatory), R. Gratton (INAF, Italy), T. Henning (Max-Planck-Institut für Astronomie, Germany), N. Hubin (European Southern Observatory), F. Joos (ETH Zurich, Institute for Astronomy, Switzerland), M. Kasper (European Southern Observatory), M. Langlois (Centre de Recherche Astrophysique de Lyon and Aix Marseille Univ, France), A. Pavlov (Max-Planck-Institut für Astronomie, Germany), J. Pragt (NOVA Optical Infrared Instrumentation Group at ASTRON, the Netherlands), P. Puget (Université Grenoble Alpes, France), S.P. Quanz (ETH Zurich, Institute for Astronomy, Switzerland), B. Salasnich (INAF, Italy), R. Siebenmorgen (European Southern Observatory), M. Stute (Simcorp GmbH, Germany), M. Suarez (European Southern Observatory), J. Szulagyi (ETH Zurich, Institute for Astronomy, Switzerland), C. Thalmann (ETH Zurich, Institute for Astronomy, Switzerland), M. Turatto (INAF, Italy), S. Udry (Geneva Observatory, Switzerland), A. Vigan (Aix Marseille Univ, France), and F. Wildi (Geneva Observatory, Switzerland).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

Links:

ESOcast 188 Light: Dancing with the Enemy: https://www.eso.org/public/videos/eso1840a/

Research paper: https://www.aanda.org/articles/aa/pdf/2017/06/aa29416-16.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

SPHERE: https://www.eso.org/public/teles-instr/paranal-observatory/vlt/vlt-instr/sphere/

NASA/ESA Hubble Space Telescope: https://www.spacetelescope.org/

Images, Text, Credits: ESO/Schmid et al./NASA/ESA/IAU and Sky & Telescope/Digitized Sky Survey 2. Acknowledgment: Davide De Martin/Videos: ESO, Digitized Sky Survey 2, ESA/Hubble, Nick Risinger (skysurvey.org). Music: astral electronic/T. Liimets et al./ESO/M. Kornmesser.

Best regards, Orbiter.ch

NASA's InSight Takes Its First Selfie

NASA - InSight Mission patch.

December 12, 2018

Image above: This is NASA InSight's first selfie on Mars. It displays the lander's solar panels and deck. On top of the deck are its science instruments, weather sensor booms and UHF antenna. The selfie was taken on Dec. 6, 2018 (Sol 10). Image Credits: NASA/JPL-Caltech.

NASA's InSight lander isn't camera-shy. The spacecraft used a camera on its robotic arm to take its first selfie - a mosaic made up of 11 images. This is the same imaging process used by NASA's Curiosity rover mission, in which many overlapping pictures are taken and later stitched together. Visible in the selfie are the lander's solar panel and its entire deck, including its science instruments.

Mission team members have also received their first complete look at InSight's "workspace" - the approximately 14-by-7-foot (4-by-2-meter) crescent of terrain directly in front of the spacecraft. This image is also a mosaic composed of 52 individual photos.

In the coming weeks, scientists and engineers will go through the painstaking process of deciding where in this workspace the spacecraft's instruments should be placed. They will then command InSight's robotic arm to carefully set the seismometer (called the Seismic Experiment for Interior Structure, or SEIS) and heat-flow probe (known as the Heat Flow and Physical Properties Package, or HP3) in the chosen locations. Both work best on level ground, and engineers want to avoid setting them on rocks larger than about a half-inch (1.3 cm).

Image above: This mosaic, composed of 52 individual images from NASA's InSight lander, shows the workspace where the spacecraft will eventually set its science instruments. Image Credits: NASA/JPL-Caltech.

"The near-absence of rocks, hills and holes means it'll be extremely safe for our instruments," said InSight's Principal Investigator Bruce Banerdt of NASA's Jet Propulsion Laboratory in Pasadena, California. "This might seem like a pretty plain piece of ground if it weren't on Mars, but we're glad to see that."

InSight's landing team deliberately chose a landing region in Elysium Planitia that is relatively free of rocks. Even so, the landing spot turned out even better than they hoped. The spacecraft sits in what appears to be a nearly rock-free "hollow" - a depression created by a meteor impact that later filled with sand. That should make it easier for one of InSight's instruments, the heat-flow probe, to bore down to its goal of 16 feet (5 meters) below the surface.

About InSight

JPL manages InSight for NASA's Science Mission Directorate. InSight is part of NASA's Discovery Program, managed by the agency's Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supports spacecraft operations for the mission.

A number of European partners, including France's Centre National d'Études Spatiales (CNES) and the German Aerospace Center (DLR), are supporting the InSight mission. CNES and the Institut de Physique du Globe de Paris (IPGP) provided the Seismic Experiment for Interior Structure (SEIS) instrument, with significant contributions from the Max Planck Institute for Solar System Research (MPS) in Germany, the Swiss Institute of Technology (ETH) in Switzerland, Imperial College London and Oxford University in the United Kingdom, and JPL. DLR provided the Heat Flow and Physical Properties Package (HP³) instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain's Centro de Astrobiología (CAB) supplied the wind sensors.

Related links:

Seismic Experiment for Interior Structure (SEIS): https://mars.nasa.gov/insight/mission/instruments/seis/

Heat Flow and Physical Properties Package (HP³): https://mars.nasa.gov/insight/mission/instruments/hp3/

For more information about InSight, and to follow along on its flight to Mars, visit: https://www.nasa.gov/insight

Images (mentioned), Text, Credits: NASA/JPL/Andrew Good.

Greetings, Orbiter.ch

Rosetta witnesses birth of baby bow shock around comet

ESA - Rosetta Mission patch.

12 December 2018

A new study reveals that, contrary to first impressions, Rosetta did detect signs of an infant bow shock at the comet it explored for two years – the first ever seen forming anywhere in the Solar System.

From 2014 to 2016, ESA’s Rosetta spacecraft studied Comet 67P/Churyumov-Gerasimenko and its surroundings from near and far. It flew directly through the ‘bow shock’ several times both before and after the comet reached its closest point to the Sun along its orbit, providing a unique opportunity to gather in situ measurements of this intriguing patch of space.

Rosetta spying infant bow shock at comet

Comets offer scientists an extraordinary way to study the plasma in the Solar System. Plasma is a hot, gaseous state of matter comprising charged particles, and is found in the Solar System in the form of the solar wind: a constant stream of particles flooding out from our star into space.

As the supersonic solar wind flows past objects in its path, such as planets or smaller bodies, it first hits a boundary known as a bow shock. As the name suggests, this phenomenon is somewhat like the wave that forms around the bow of a ship as it cuts through choppy water.

Bow shocks have been found around comets, too – Halley’s comet being a good example. Plasma phenomena vary as the medium interacts with the surrounding environment, changing the size, shape, and nature of structures such as bow shocks over time.

Rosetta looked for signs of such a feature over its two-year mission, and ventured over 1500 km away from 67P’s centre on the hunt for large-scale boundaries around the comet – but apparently found nothing.

“We looked for a classical bow shock in the kind of area we’d expect to find one, far away from the comet’s nucleus, but didn’t find any, so we originally reached the conclusion that Rosetta had failed to spot any kind of shock,” says Herbert Gunell of the Royal Belgian Institute for Space Aeronomy, Belgium, and Umeå University, Sweden, one of the two scientists who led the study.

“However, it seems that the spacecraft actually did find a bow shock, but that it was in its infancy. In a new analysis of the data, we eventually spotted it around 50 times closer to the comet’s nucleus than anticipated in the case of 67P. It also moved in ways we didn’t expect, which is why we initially missed it.”

Bow shock taking shape at comet

On 7 March 2015, when the comet was over twice as far from the Sun as the Earth and heading inwards towards our star, Rosetta data showed signs of a bow shock beginning to form. The same indicators were present on its way back out from the Sun, on 24 February 2016.

This boundary was observed to be asymmetric, and wider than the fully developed bow shocks observed at other comets.

“Such an early phase of the development of a bow shock around a comet had never been captured before Rosetta,” says co-lead Charlotte Goetz of the Institute for Geophysics and Extraterrestrial Physics in Braunschweig, Germany.

“The infant shock we spotted in the 2015 data will have later evolved to become a fully developed bow shock as the comet approached the Sun and became more active – we didn't see this in the Rosetta data, though, as the spacecraft was too close to 67P at that time to detect the ‘adult’ shock. When Rosetta spotted it again, in 2016, the comet was on its way back out from the Sun, so the shock we saw was in the same state but ‘unforming’ rather than forming.”

Herbert, Charlotte, and colleagues explored data from the Rosetta Plasma Consortium, a suite of instruments comprising five different sensors to study the plasma surrounding Comet 67P. They combined the data with a plasma model to simulate the comet’s interactions with the solar wind and determine the properties of the bow shock. 

Simulated view

The scientists found that, when the forming bow shock washed over Rosetta, the comet’s magnetic field became stronger and more turbulent, with bursts of highly energetic charged particles being produced and heated in the region of the shock itself. Beforehand, particles had been slower-moving, and the solar wind had been generally weaker – indicating that Rosetta had been ‘upstream’ of a bow shock.

“These observations are the first of a bow shock before it fully forms, and are unique in being gathered on-location at the comet and shock itself,” says Matt Taylor, ESA Rosetta Project Scientist.

“This finding also highlights the strength of combining multi-instrument measurements and simulations. It may not be possible to solve a puzzle using one dataset, but when you bring together multiple clues, as in this study, the picture can become clearer and offer real insight into the complex dynamics of our Solar System – and the objects in it, like 67P.”

Notes for Editors:

"The infant bow shock: a new frontier at a weak activity comet" by H. Gunell et al is published in Astronomy & Astrophysics, November 2018: https://doi.org/10.1051/0004-6361/201834225

The study used ion spectra from the Ion Composition Analyzer of the Rosetta Plasma Consortium (RPC-ICA), ion and electron spectra from the Ion and Electron Sensor (RPC-IES), and magnetic flux density measurements from the magnetometer instrument (RPC-MAG).

Related link:

Rosetta: http://www.esa.int/Our_Activities/Space_Science/Rosetta

Images, Video, Text, Credits: ESA/Markus Bauer/Matt Taylor/Institute for Geophysics and Extraterrestrial Physics TU Braunschweig/Charlotte Goetz/Royal Belgian Institute for Space Aeronomy/Umeå University/Herbert Gunell.


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NASA’s First Stellar Observatory, OAO 2, Turns 50

NASA - Orbiting Astronomical Observatory (OAO) 2 patch.

Dec. 11, 2018

At 3:40 a.m. EST on Saturday, Dec. 7, 1968, just three weeks before the highly anticipated launch of Apollo 8 and the first crewed flight to the Moon, an Atlas-Centaur rocket carrying NASA’s heaviest and most ambitious unpiloted satellite at the time blasted into the sky from Launch Complex 36B at Cape Canaveral Air Force Station, Florida.

Formally known as the Orbiting Astronomical Observatory (OAO) 2 and nicknamed Stargazer, it would become NASA’s first successful cosmic explorer and the direct ancestor of Hubble, Chandra, Swift, Kepler, FUSE, GALEX and many other astronomy satellites.

OAO 2 provided the first orbital stellar observations in ultraviolet light, shorter than wavelengths in the visible range spanning 3,800 (violet) to 7,500 (red) angstroms. Much of UV light is screened out by the atmosphere and unavailable to ground-based telescopes. Stargazer’s experiments made nearly 23,000 measurements, showed that young, hot stars were hotter than theoretical models of the time indicated, confirmed that comets are surrounded by vast clouds of hydrogen and discovered a curious feature of the interstellar medium that would take decades to understand.

“OAO 2 was a learning experience,” said Nancy Grace Roman, the first chief of astronomy in the Office of Space Science at NASA Headquarters, Washington. “We had to learn how to point a telescope to a single object and hold it there for a half hour or so.” This makes OAO 2 the ancestor of all space telescopes that can point to a given spot on the sky and track it for an extended period.

Seas of Infinity: OAO 2's 50th Anniversary

Video above: Watch James Kupperian Jr., the project scientist for NASA’s Orbiting Astronomical Observatories, explain the Stargazer (OAO 2) satellite and its instruments in this excerpt from “Seas of Infinity,” a 1968 NASA film about the mission. Image Credit: NASA.

The feat proved much harder to accomplish than anyone had expected a decade earlier, at the outset of the program. But the development of star trackers — small telescopes located around the spacecraft that lock onto appropriate guide stars — and associated control software enabled extended UV observations that were previously impossible.

Prior to OAO 2, ultraviolet observations of stars were acquired by suborbital sounding rockets that collect data for only five minutes each flight as they arc above much of the atmosphere. By 1968, it was estimated that sounding rockets had captured a total of three hours of stellar UV measurements in some 40 flights. OAO 2 could collect more data than this in a single day.

In June 1958, the National Academy of Science established the 15-member Space Science Board, chaired by Lloyd Berkner, to help advise the “possible new civilian space agency” — NASA, which was established the following month when the National Aeronautics and Space Act was signed into law. After the panel’s first meeting, Berkner contacted hundreds of U.S. scientists for recommendations on experiments that could be performed by a satellite with a modest payload.

At the end of the year, James Kupperian Jr., a physicist at the Naval Research Laboratory in Washington, first used “Orbiting Astronomical Observatories” in an outline of the project. The name stuck. In 1959, he moved to NASA’s Goddard Space Flight Center in Greenbelt, Maryland, to become chief of its astrophysics branch and serve as project scientist for all four OAO missions.

Image above: Technicians in a clean room at NASA’s Kennedy Space Center in Cape Canaveral, Florida, check out the Orbiting Astronomical Observatory 2 before the mission’s Dec. 7, 1968, launch. The white conical structures visible near the top of the spacecraft are two of its six star trackers, small telescopes that lock onto appropriate guide stars to keep the instruments on target. Image Credit: NASA.

Two astronomers who responded to Berkner’s request had already determined that ultraviolet observations of stars should be the initial focus for orbital astronomy. The first was Fred Whipple, director of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, who became the principal investigator for OAO 2’s Project Celescope (from “celestial telescope”). The experiment used four television cameras to make two-degree-square images of the sky in UV wavelengths between 1,200 and 3,250 angstroms.

The other scientist was Arthur Code, a professor of astronomy at the University of Wisconsin-Madison and director of its Washburn Observatory. Code became the principal investigator on the Wisconsin Experiment Package (WEP), a suite of seven telescopes. Four were designed to measure the UV brightness of stars from 1,330 to 4,250 angstroms, and a fifth, operating from 2,130 to 3,330 angstroms, was optimized for measuring the brightness of extended objects like nebulosity. Two scanning spectrometers recorded target spectra from 1,050 to 3,800 angstroms in 100 angstrom steps and at different resolutions.

“It’s kind of interesting that this project grew out of an institution that had never done photographic astronomy,” notes Jordan Marché II, an adjunct professor of astronomy at the University of Wisconsin, Madison. At the time, imaging, processing and measuring photographic plates was a typical aspect of astronomical work, but Code and his colleagues emphasized photometric studies over photography. “They were in this completely different mode of thinking about doing research,” Marché said.

Both experiments were mounted back-to-back within the 4,436-pound (2,012 kilogram) spacecraft and looked out opposite ends, taking turns viewing the universe.

The first WEP flew aboard OAO 1 on April 8, 1966, along with X-ray and gamma-ray experiments from Lockheed, MIT and Goddard. Just seven minutes after separation from its rocket, the spacecraft began experiencing problems in its power supply, including high-voltage arcing in the star trackers. After three days and 20 orbits, controllers terminated the mission without activating any of the experiments.

Take a "Swift" Tour of the Andromeda Galaxy

Video above: Take a tour of the best-ever UV image of our neighboring Andromeda Galaxy (M31), the closest large spiral to our own. Using its Ultraviolet/Optical Telescope, NASA’s Neil Gehrels Swift Observatory acquired 330 images in three UV colors. Some 20,000 ultraviolet sources are visible here, including M32, a small galaxy in orbit around M31. Dense clusters of hot, young, blue stars light up the disk beyond the galaxy's smooth, redder central bulge. M31 is located 2.5 million light-years away. Video Credits: NASA/Swift/Stefan Immler (Goddard) and Erin Grand (University of Maryland, College Park).

OAO 2 fared much better, continuing to work until it was shut down in February 1973. Issues with the Celescope — primarily a gradual loss of sensitivity in its modified TV tube detectors, called uvicons — resulted in the experiment being turned off in April 1970. By then, the Celescope had captured some 8,500 images across 10 percent of the sky, and Whipple’s team ultimately published a catalog of 5,068 UV stars.

The WEP experienced fewer problems. Some weeks after launch, a calibration source in the nebula photometer stuck in place, allowing no further data to be returned from that telescope. But while the filters in the other telescopes showed some degradation in orbit, the instruments performed well and were functioning when the spacecraft was shut down.

In addition to providing important UV data on some 1,200 stars, the WEP also observed planets, galaxies and comets. One of its most striking finds occurred in early 1970, when the instrument observed comet Tago-Sato-Kosaka, which had recently rounded the Sun and was headed back out into deep space. Observations showed the comet was surrounded by a UV-emitting cloud of hydrogen bigger than the Sun, dwarfing the comet’s visible structure; a similar feature was seen around comet Bennett later that year. These findings confirmed earlier predictions based on the idea that a comet’s tiny solid nucleus was largely made of frozen water. Solar ultraviolet light breaks up water molecules streaming off the icy nucleus, resulting in a sparse but vast envelope of hydrogen atoms that scatters UV sunlight.

Image above: An illustration of OAO 2, nicknamed Stargazer, in orbit around Earth. Image Credit: NASA.

One of the most interesting results from OAO 2 involved interstellar extinction, a measure of the way matter between the stars absorbs and scatters light. The WEP showed there was a narrow extinction “bump” — that is, an increase in the way UV light was absorbed or scattered — centered at about 2,175 angstroms. Early speculation suggested that this feature may represent evidence for graphite dust grains. But theorists have introduced more exotic possibilities in the decades since, including nanodiamonds, graphite “onions,” molecules called polycyclic aromatic hydrocarbons (PAHs) and fullerenes, large, hollow soccer-ball-shaped molecules formed by carbon atoms.

“The problem is that many of the exotic forms discussed are not likely to be sufficiently abundant in interstellar space,” said John Bradley, a researcher at the University of Hawaii at Manoa who has been intrigued by the UV bump for 20 years. Bradley and his colleagues identified a similar spectral feature from PAHs embedded within interplanetary dust particles. “PAHs are everywhere,” he said, “and they are most likely the source of the bump, possibly with the addition of closely related fullerene-like molecules.”

Related links:

GALEX (Galaxy Evolution Explorer): http://www.nasa.gov/mission_pages/galex/index.html

Hubble Space Telescope (HST): https://www.nasa.gov/mission_pages/hubble/main/index.html

Swift: http://www.nasa.gov/mission_pages/swift/main/index.html

NASA History: https://www.nasa.gov/topics/history/index.html

Images (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Francis Reddy.

Greetings, Orbiter.ch

Russian Spacewalkers Complete Crew Vehicle Inspection

ROSCOSMOS - Soyuz MS-09 Mission patch / EVA - Extra Vehicular Activities patch.

December 11, 2018

Expedition 57 Flight Engineers Oleg Kononenko and Sergey Prokopyev of Roscosmos completed a spacewalk lasting 7 hours and 45 minutes.

Image above: Spacewalker Oleg Kononenko is on the Strela boom getting ready for inspection work on the Soyuz crew vehicle. Image Credit: NASA TV.

The two cosmonauts opened the hatch to the Pirs docking compartment to begin the spacewalk at 10:59 a.m. EST. They re-entered the airlock and closed the hatch at 6:44 p.m. EST.

Soyuz MS-09 inspected by cosmonauts

During the spacewalk, the two examined the external hull of the Russian Soyuz MS-09 spacecraft attached to the space station, took images, and applied a thermal blanket. They also retrieved science experiments from the Rassvet module before heading back inside.

It was the 213th spacewalk in support of International Space Station assembly, maintenance and upgrades, the fourth for Kononenko, and the second for Prokopyev.

Image above: A pair of empty Orlan spacesuits are seen inside the Pirs Docking Compartment airlock where cosmonauts stage Russian spacewalks. Image Credit: NASA.

Prokopyev, NASA astronaut Serena Auñón-Chancellor, and ESA (European Space Agency) astronaut Alexander Gerst are scheduled to depart the station in the Soyuz MS-09 at 8:42 p.m. Dec. 19, returning home to Earth after a six-and-half-month mission.

Related links:

Pirs docking compartment: https://www.nasa.gov/mission_pages/station/structure/elements/pirs-docking-compartment

213th spacewalk: http://www.nasa.gov/mission_pages/station/spacewalks

Soyuz MS-09: https://www.nasa.gov/feature/soyuz-launches-arrivals-and-departures

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA/Mark Garcia/NASA TV/SciNews.

Best regards, Orbiter.ch

Space Station Science Highlights: Week of December 3, 2018

ISS - Expedition 57 Mission patch.

Dec. 11, 2018

NASA astronaut Anne McClain, David Saint-Jacques of the Canadian Space Agency, and Oleg Konenenko of the Russian space agency Roscosmos joined Expedition 57 Commander Alexander Gerst of ESA (European Space Agency), Serena Auñón-Chancellor of NASA, and Sergey Prokopyev of Roscosmos aboard the International Space Station last week.

Image above: NASA astronaut Anne McClain, David Saint-Jacques of the Canadian Space Agency, and Oleg Konenenko of the Russian space agency Roscosmos joined Expedition 57 Commander Alexander Gerst of ESA (European Space Agency),Serena Auñón-Chancellor of NASA, and Sergey Prokopyev of Roscosmos aboard the space station last week. Image Credit: NASA.

In addition to expanding the crew, the station also received tons of new science aboard the SpaceX CRS-16 Dragon. Science included investigations like Molecular Muscle, Rodent Research-8, Perfect Crystals and many more.

Image above: Dragon’s 16th mission to the orbital lab will deliver almost 5,700 pounds of science, crew supplies and hardware. Image Credit: NASA.

Here’s a look at some of the science conducted last week aboard the orbiting lab:

Habitats readied for rodent investigation

Spending a lot of time in space causes changes to the human body, including bone, muscle, the cardiovascular system and the immune system. Similar changes occur as people age on Earth. That makes spaceflight an opportunity to study – and perhaps lessen – the effects of aging. 

Rodent Research-8 (RR-8) examines the physiology of aging and the effect of age on disease progression using groups of young and old mice flown in space and kept on Earth. Last week, crew members prepared for the arrival of the mice by installing two habitats and stowing habitats used in previous investigations.

Spinning science: cement solidification in space

Solidifying cement in microgravity minimizes gravity-driven phenomena and creates a different microstructure than that observed in typical laboratory conditions on Earth. Understanding the process in microgravity is essential to advancing the ultimate use of cement in extraterrestrial settings, such as Mars or the Moon.

MVP-Cell-05 investigates the complex process of cement solidification at various levels of gravity (lunar, Mars and 0.7 g). The MVP facility, used to conduct research in space with a wide variety of sample types, includes internal carousels that simultaneously can produce up to 2 g of artificial gravity.

Last week, a crewmember mixed control and experiment samples within the portable glove bag. Eight experiment samples were inserted into the MVP centrifuge facility to simulate 0.7 g.

Learn more about the MVP facility here: https://www.nasa.gov/mission_pages/station/research/news/Spinning_Science_MVP_Arrives_At_ISS

Image above: NASA astronaut and station commander Alexander Gerst working on the CASIS PCG-16 investigation. CASIS PCG-16 evaluates growth of LRRK2 protein crystals in microgravity, a protein implicated in Parkinson’s disease. Image Credit: NASA.

Virtual reality sessions test sensory perception aboard orbiting lab

The VECTION investigation, sponsored by the Canadian Space Agency (CSA), examines how lack of gravity disrupts a person’s ability to visually interpret motion, orientation and distance. A better understanding of the vestibular system and its involvement in sensory perception – learning when and how to trust their eyes, touch and other senses – could help humans in a range of environments, from under water to outer space.

Last week, a crew member performed configuration steps for the VECTION software, as well as verification of the virtual reality headset and trackball components. Later, crew members deployed the VECTION hardware and performed experiment sessions, downlinking data to the ground afterwards. 

To learn more about this investigation, click here: https://www.nasa.gov/mission_pages/station/research/news/human_senses_in_space

Other work was done on these investigations:

- CASIS PCG 16 evaluates growth of LRRK2 protein crystals in microgravity. LRRK2 is implicated in Parkinson’s disease, but crystals of the protein grown on Earth are too small and compact to study: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7855

- Cemsica tests using particles of calcium-silicate (C-S) to synthesize nanoporous membranes (those with pores 100 nanometers or smaller) that can separate carbon dioxide (CO2) molecules from air or other gases: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7721

- The Marrow investigation studies the effect of microgravity on bone marrow. It is believed that microgravity, like long-duration bed rest on Earth, has a negative effect on the bone marrow and the blood cells that are produced in the bone marrow: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1673

- Molecular Muscle examines the molecular mechanisms behind muscle loss and the potential for developing countermeasures targeting those mechanisms: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7576

- Behavioral Core Measures examines an integrated, standardized suite of measurements for its ability to rapidly and reliably assess the risk of adverse cognitive or behavioral conditions and psychiatric disorders during long-duration spaceflight: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7537

- Standard Measures collects a set of core measurements related to many human spaceflight risks from astronauts before, during, and after long-duration missions. The aim is to ensure consistent capture of an optimized, minimal set of measures from crew members until the end of the International Space Station Program in order to characterize the adaptive responses to and risks of living in space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7711

Space to Ground: Four Orbits Later: 12/07/2018

Related links:

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

SpaceX CRS-16 Dragon: https://www.nasa.gov/mission_pages/station/research/news/spx16-research

Molecular Muscle: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7576

Rodent Research-8: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7713

Perfect Crystals: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7617

MVP-Cell-05: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7874

VECTION: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7484

Canadian Space Agency (CSA): https://www.canada.ca/en/space-agency.html

Spot the Station: https://spotthestation.nasa.gov/

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/Vic Cooley, Lead Increment Scientist Expeditions 57/58.

Best regards, Orbiter.ch