Does New Horizons’ Next Target Have a Moon?

NASA - New Horizons Mission logo.

Dec. 12, 2017

Image Credits: NASA/JHUAPL/SwRI

Scientists were already excited to learn this summer that New Horizons’ next flyby target – a Kuiper Belt object a billion miles past Pluto -- might be either peanut-shaped or even two objects orbiting one another. Now new data hints that 2014 MU69 might have orbital company: a small moon.

That’s the latest theory coming from NASA’s New Horizons team, as it continues to analyze telescope data on the target of a New Year’s Day 2019 flyby. “We really won’t know what MU69 looks like until we fly past it, or even gain a full understanding of it until after the encounter,” said New Horizons science team member Marc Buie, of the Southwest Research Institute, Boulder, Colorado, who offered an update on the analysis of MU69 Monday at the American Geophysical Union Fall Meeting in New Orleans. “But even from afar, the more we examine it, the more interesting and amazing this little world becomes.”

The data that led to these hints at MU69’s nature were gathered over six weeks in June and July, when the team made three attempts to place telescopes in the narrow shadow of MU69 as it passed in front of a star. The most valuable recon came on July 17, when five telescopes deployed by the New Horizons team in Argentina were in the right place at the right time to catch this fleeting shadow — an event known as an occultation – and capture important data on MU69’s size, shape and orbit. That data raised the possibility that MU69 might be two like-sized objects, or what’s known as a binary.

Images above: On three occasions in June and July 2017, New Horizons mission team members attempted to track a small, distant Kuiper Belt object, 2014 MU69, as it passed in front of a star – an event known as an occultation. The colored lines mark the path of the star as seen from different telescopes on each day; the blank spaces on those lines indicate the few seconds when MU69 blocked the light from the star. Scientists are using these observations to craft a picture of MU69 and any companion bodies. Images Credits: NASA/JHUAPL/SwRI/James Tuttle Keane.

The prospect that MU69 might have a moon arose from data collected during a different occultation on July 10, by NASA's airborne Stratospheric Observatory for Infrared Astronomy (SOFIA). Focused on MU69’s expected location while flying over the Pacific Ocean, SOFIA detected what appeared to be a very short drop-out in the star’s light. Buie said further analysis of that data, including syncing it with MU69 orbit calculations provided by the European Space Agency’s Gaia mission, opens the possibility that the “blip” SOFIA detected could be another object around MU69.

“A binary with a smaller moon might also help explain the shifts we see in the position of MU69 during these various occultations,” Buie added. “It’s all very suggestive, but another step in our work to get a clear picture of MU69 before New Horizons flies by, just over a year from now.”

New Horizons probe. Image Credits: NASA/JHUAPL/SwRI

That flyby will be the most distant in the history of space exploration. Ancient Kuiper Belt object MU69, just discovered in 2014, is more than 4 billion miles (6.5 billion kilometers) from Earth. It appears to be no more than 20 miles (30 kilometers) long, or, if a binary, each about 9-12 miles (15-20 kilometers) in diameter. Like other objects in the Kuiper Belt, MU69 offers a close-up look at the remnants of the ancient planet-building process, small worlds that hold critical clues to the formation of the outer solar system.

“The occultation effort that Marc Buie and his team led for New Horizons has been invaluable in opening our eyes to the very real possibilities that MU69 is both a lot more complex than anyone suspected, and that it holds many surprises for us at flyby on New Year’s Eve and New Year’s Day, 2019,” added New Horizons Principal Investigator Alan Stern, also from Southwest Research Institute. “The allure of its exploration is becoming stronger and stronger as we learn more and more about it. It’s just fantastic!”

Related links:

NASA's airborne Stratospheric Observatory for Infrared Astronomy (SOFIA): https://www.nasa.gov/mission_pages/SOFIA/index.html

New Horizons: http://www.nasa.gov/mission_pages/newhorizons/main/index.html

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

Best regards, Orbiter.ch

Chandra Reveals the Elementary Nature of Cassiopeia A

NASA - Chandra X-ray Observatory patch.

December 12, 2017

Where do most of the elements essential for life on Earth come from? The answer: inside the furnaces of stars and the explosions that mark the end of some stars’ lives.

Astronomers have long studied exploded stars and their remains – known as “supernova remnants” – to better understand exactly how stars produce and then disseminate many of the elements observed on Earth, and in the cosmos at large.

Due to its unique evolutionary status, Cassiopeia A (Cas A) is one of the most intensely studied of these supernova remnants. A new image from NASA’s Chandra X-ray Observatory shows the location of different elements in the remains of the explosion: silicon (red), sulfur (yellow), calcium (green) and iron (purple). Each of these elements produces X-rays within narrow energy ranges, allowing maps of their location to be created. The blast wave from the explosion is seen as the blue outer ring.

X-ray telescopes such as Chandra are important to study supernova remnants and the elements they produce because these events generate extremely high temperatures – millions of degrees – even thousands of years after the explosion. This means that many supernova remnants, including Cas A, glow most strongly at X-ray wavelengths that are undetectable with other types of telescopes.


Chandra’s sharp X-ray vision allows astronomers to gather detailed information about the elements that objects like Cas A produce. For example, they are not only able to identify many of the elements that are present, but how much of each are being expelled into interstellar space. 



The Chandra data indicate that the supernova that produced Cas A has churned out prodigious amounts of key cosmic ingredients. Cas A has dispersed about 10,000 Earth masses worth of sulfur alone, and about 20,000 Earth masses of silicon. The iron in Cas A has the mass of about 70,000 times that of the Earth, and astronomers detect a whopping one million Earth masses worth of oxygen being ejected into space from Cas A, equivalent to about three times the mass of the sun. (Even though oxygen is the most abundant element in Cas A, its X-ray emission is spread across a wide range of energies and cannot be isolated in this image, unlike with the other elements that are shown.)



Astronomers have found other elements in Cas A in addition to the ones shown in this new Chandra image. Carbon, nitrogen, phosphorus and hydrogen have also been detected using various telescopes that observe different parts of the electromagnetic spectrum. Combined with the detection of oxygen, this means all of the elements needed to make DNA, the molecule that carries genetic information, are found in Cas A.



Oxygen is the most abundant element in the human body (about 65% by mass), calcium helps form and maintain healthy bones and teeth, and iron is a vital part of red blood cells that carry oxygen through the body. All of the oxygen in the Solar System comes from exploding massive stars. About half of the calcium and about 40% of the iron also come from these explosions, with the balance of these elements being supplied by explosions of smaller mass, white dwarf stars. 



While the exact date is not confirmed, many experts think that the stellar explosion that created Cas A occurred around the year 1680 in Earth’s timeframe. Astronomers estimate that the doomed star was about five times the mass of the Sun just before it exploded. The star is estimated to have started its life with a mass about 16 times that of the Sun, and lost roughly two-thirds of this mass in a vigorous wind blowing off the star several hundred thousand years before the explosion.



Chandra X-ray Observatory. Animation Credits: NASA/CXC

Earlier in its lifetime, the star began fusing hydrogen and helium in its core into heavier elements through the process known as “nucleosynthesis.” The energy made by the fusion of heavier and heavier elements balanced the star against the force of gravity. These reactions continued until they formed iron in the core of the star.  At this point, further nucleosynthesis would consume rather than produce energy, so gravity then caused the star to implode and form a dense stellar core known as a neutron star.

The exact means by which a massive explosion is produced after the implosion is complicated, and a subject of intense study, but eventually the infalling material outside the neutron star was transformed by further nuclear reactions as it was expelled outward by the supernova explosion.

Chandra has repeatedly observed Cas A since the telescope was launched into space in 1999. The different datasets have revealed new information about the neutron star in Cas A, the details of the explosion, and specifics of how the debris is ejected into space.



NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Image Credits: NASA/CXC/SAO.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2017/casa_life/

Formore Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Chandra X-Ray Observatory: https://www.nasa.gov/mission_pages/chandra/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Lee Mohon.

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Bright Areas on Ceres Suggest Geologic Activity

NASA - Dawn Mission patch.

December 12, 2017

Occator Perspective View

Image above: The bright areas of Occator Crater -- Cerealia Facula in the center and Vinalia Faculae to the side -- are examples of bright material found on crater floors on Ceres. This is a simulated perspective view. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA PSI.

If you could fly aboard NASA's Dawn spacecraft, the surface of dwarf planet Ceres would generally look quite dark, but with notable exceptions. These exceptions are the hundreds of bright areas that stand out in images Dawn has returned. Now, scientists have a better sense of how these reflective areas formed and changed over time -- processes indicative of an active, evolving world.

"The mysterious bright spots on Ceres, which have captivated both the Dawn science team and the public, reveal evidence of Ceres' past subsurface ocean, and indicate that, far from being a dead world, Ceres is surprisingly active. Geological processes created these bright areas and may still be changing the face of Ceres today," said Carol Raymond, deputy principal investigator of the Dawn mission, based at NASA's Jet Propulsion Laboratory in Pasadena, California. Raymond and colleagues presented the latest results about the bright areas at the American Geophysical Union meeting in New Orleans on Tuesday, Dec. 12.

Different Kinds of Bright Areas

Since Dawn arrived in orbit at Ceres in March 2015, scientists have located more than 300 bright areas on Ceres. A new study in the journal Icarus, led by Nathan Stein, a doctoral researcher at Caltech in Pasadena, California, divides Ceres' features into four categories.

The first group of bright spots contains the most reflective material on Ceres, which is found on crater floors. The most iconic examples are in Occator Crater, which hosts two prominent bright areas. Cerealia Facula, in the center of the crater, consists of bright material covering a 6-mile-wide (10-kilometer-wide) pit, within which sits a small dome. East of the center is a collection of slightly less reflective and more diffuse features called Vinalia Faculae. All the bright material in Occator Crater is made of salt-rich material, which was likely once mixed in water. Although Cerealia Facula is the brightest area on all of Ceres, it would resemble dirty snow to the human eye.

The Bright Stuff: New NASA Dawn Findings at Ceres

More commonly, in the second category, bright material is found on the rims of craters, streaking down toward the floors. Impacting bodies likely exposed bright material that was already in the subsurface or had formed in a previous impact event.

Separately, in the third category, bright material can be found in the material ejected when craters were formed.

The mountain Ahuna Mons gets its own fourth category -- the one instance on Ceres where bright material is unaffiliated with any impact crater. This likely cryovolcano, a volcano formed bythe gradual accumulation of thick, slowly flowing icy materials, has prominent bright streaks on its flanks.

Oxo Crater at LAMO

Image above: Oxo Crater is an example of bright material found on the rims of a crater on Ceres. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI.

Over hundreds of millions of years, bright material has mixed with the dark material that forms the bulk of Ceres' surface, as well as debris ejected during impacts. That means billions of years ago, when Ceres experienced more impacts, the dwarf planet's surface likely would have been peppered with thousands of bright areas.

"Previous research has shown that the bright material is made of salts, and we think subsurface fluid activity transported it to the surface to form some of the bright spots," Stein said.

The Case of Occator

Why do the different bright areas of Occator seem so distinct from one another? Lynnae Quick, a planetary geologist at the Smithsonian Institution in Washington, has been delving into this question.

The leading explanation for what happened at Occator is that it could have had, at least in the recent past, a reservoir of salty water beneath it. Vinalia Faculae, the diffuse bright regions to the northeast of the crater's central dome, could have formed from a fluid driven to the surface by a small amount of gas, similar to champagne surging out of its bottle when the cork is removed.

Haulani Crater in Enhanced Color

Image above: Ahuna Mons, Ceres' unique tall mountain, hosts the only example of bright material on Ceres that is not associated with an impact. This is a simulated perspective view. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

In the case of the Vinalia Faculae, the dissolved gas could have been a volatile substance such as water vapor, carbon dioxide, methane or ammonia. Volatile-rich salty water could have been brought close to Ceres' surface through fractures that connected to the briny reservoir beneath Occator. The lower pressure at Ceres' surface would have caused the fluid to boil off as a vapor. Where fractures reached the surface, this vapor could escape energetically, carrying with it ice and salt particles and depositing them on the surface.

Cerealia Facula must have formed in a somewhat different process, given that it is more elevated and brighter than Vinalia Faculae. The material at Cerealia may have been more like an icy lava, seeping up through the fractures and swelling into a dome. Intermittent phases of boiling, similar to what happened when Vinalia Faculae formed, may have occurred during this process, littering the surface with ice and salt particles that formed the Cerealia bright spot.

Ahuna Mons: Side View

Image above: Ahuna Mons, Ceres' unique tall mountain, hosts the only example of bright material on Ceres that is not associated with an impact. This is a simulated perspective view. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Quick's analyses do not depend on the initial impact that formed Occator. However, the current thinking among Dawn scientists is that when a large body slammed into Ceres, excavating the 57-mile-wide (92-kilometer-wide) crater, the impact may have also created fractures through which liquid later emerged.

"We also see fractures on other solar system bodies, such as Jupiter's icy moon Europa," Quick said. "The fractures on Europa are more widespread than the fractures we see at Occator. However, processes related to liquid reservoirs that might exist beneath Europa's cracks today could be used as a comparison for what may have happened at Occator in the past."

Map of Ceres' Bright Spots

Image above: This map from NASA's Dawn mission shows locations of bright material on dwarf planet Ceres. There are more than 300 bright areas, called "faculae," on Ceres. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI/Caltech.

As Dawn continues the final phase of its mission, in which it will descend to lower altitudes than ever before, scientists will continue learning about the origins of the bright material on Ceres and what gave rise to the enigmatic features in Occator.

The Dawn mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: https://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

https://www.nasa.gov/dawn

https://dawn.jpl.nasa.gov

Images (mentioned), Video, Text, Credits: NASA/JPL/Elizabeth Landau.

Greetings, Orbiter.ch

Galileo launch brings navigation network close to completion

ARIANESPACE - Ariane 5 / Flight VA240 Mission poster.


12 December 2017

Galileo lifts off

Europe has four more Galileo navigation satellites in the sky following their launch on an Ariane 5 rocket. After today’s success, only one more launch remains before the Galileo constellation is complete and delivering global coverage.

Video above: Arianespace orbits four more Galileo satellites as Ariane 5 logs 82nd successful launch in a row.

Ariane 5, operated by Arianespace under contract to ESA, lifted off from Europe’s Spaceport in Kourou, French Guiana at 18:36 GMT (19:36 CET, 15:36 local time), carrying Galileo satellites 19–22. The first pair of 715 kg satellites was released almost 3 hours 36 minutes after liftoff, while the second pair separated 20 minutes later.

They were released into their target 22 922 km-altitude orbit by the dispenser atop the Ariane 5 upper stage. In the coming days, this quartet will be steered into their final working orbits. There, they will begin around six months of tests – performed by the European Global Navigation Satellite System Agency (GSA) – to check they are ready to join the working Galileo constellation.

Four Galileos on Ariane 5

This mission brings the Galileo system to 22 satellites. Initial Services began almost a year ago, on 15 December 2016.

“Today’s launch is another great achievement, taking us within one step of completing the constellation,” remarked Jan Wörner, ESA’s Director General.

“It is a great achievement of our industrial partners OHB (DE) and SSTL (GB) for the satellites, as well as Thales-Alenia-Space (FR, IT) and Airbus Defense and Space (GB, FR) for the ground segment and all their subcontractors throughout Europe, that Europe now has a formidable global satellite navigation system with remarkable performance.”

Galileos atop Ariane 5

Paul Verhoef, ESA’s Director of Navigation, added: “ESA is the design agent, system engineer and procurement agent of Galileo on behalf of the European Commission. Galileo is now an operating reality, so, in July, operational oversight of the system was passed to the GSA.

“Accordingly, GSA took control of these satellites as soon as they separated from their launcher, with ESA maintaining an advisory role. This productive partnership will continue with the next Galileo launch, by Ariane 5 in mid-2018. 

Related links:

What is Galileo?: http://www.esa.int/Our_Activities/Navigation/Galileo/What_is_Galileo

EC Galileo website: http://ec.europa.eu/growth/sectors/space/galileo/index_en.htm

European GNSS Agency: http://www.gsa.europa.eu/

Use Galileo: http://www.usegalileo.eu/EN/

Images, Video, Text, Credits: ARIANESPACE/ESA/Manuel Pedoussaut/Pierre Carril, 2017.

Best regards, Orbiter.ch

NASA's Juno Probes the Depths of Jupiter's Great Red Spot

NASA - JUNO Mission logo.

Dec. 11, 2017

Data collected by NASA's Juno spacecraft during its first pass over Jupiter's Great Red Spot in July 2017 indicate that this iconic feature penetrates well below the clouds. Other revelations from the mission include that Jupiter has two previously uncharted radiation zones. The findings were announced Monday at the annual American Geophysical Union meeting in New Orleans.

The Great Red Spot Plunge

Video above: This animation takes the viewer on a simulated flight into, and then out of, Jupiter’s upper atmosphere at the location of the Great Red Spot. It was created by combining an image from the JunoCam imager on NASA's Juno spacecraft with a computer-generated animation. Video Credit: NASA.

"One of the most basic questions about Jupiter's Great Red Spot is: how deep are the roots?" said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "Juno data indicate that the solar system's most famous storm is almost one-and-a-half Earths wide, and has roots that penetrate about 200 miles (300 kilometers) into the planet's atmosphere."

The science instrument responsible for this in-depth revelation was Juno's Microwave Radiometer (MWR). "Juno's Microwave Radiometer has the unique capability to peer deep below Jupiter's clouds," said Michael Janssen, Juno co-investigator from NASA's Jet Propulsion Laboratory in Pasadena, California. "It is proving to be an excellent instrument to help us get to the bottom of what makes the Great Red Spot so great."

Jupiter's Great Red Spot is a giant oval of crimson-colored clouds in Jupiter's southern hemisphere that race counterclockwise around the oval's perimeter with wind speeds greater than any storm on Earth. Measuring 10,000 miles (16,000 kilometers) in width as of April 3, 2017, the Great Red Spot is 1.3 times as wide as Earth.

Image above: This graphic shows a new radiation zone Juno detected surrounding Jupiter, located just above the atmosphere near the equator. Also indicated are regions of high-energy, heavy ions Juno observed at high latitudes. Image Credits: NASA/JPL-Caltech/SwRI/JHUAPL.

"Juno found that the Great Red Spot's roots go 50 to 100 times deeper than Earth's oceans and are warmer at the base than they are at the top," said Andy Ingersoll, professor of planetary science at Caltech and a Juno co-investigator. "Winds are associated with differences in temperature, and the warmth of the spot's base explains the ferocious winds we see at the top of the atmosphere."

The future of the Great Red Spot is still very much up for debate. While the storm has been monitored since 1830, it has possibly existed for more than 350 years. In the 19th century, the Great Red Spot was well over two Earths wide. But in modern times, the Great Red Spot appears to be diminishing in size, as measured by Earth-based telescopes and spacecraft. At the time NASA's Voyagers 1 and 2 sped by Jupiter on their way to Saturn and beyond, in 1979, the Great Red Spot was twice Earth's diameter. Today, measurements by Earth-based telescopes indicate the oval that Juno flew over has diminished in width by one-third and height by one-eighth since Voyager times.

Juno also has detected a new radiation zone, just above the gas giant's atmosphere, near the equator. The zone includes energetic hydrogen, oxygen and sulfur ions moving at almost light speed.

Image above: This figure gives a look down into Jupiter's Great Red Spot, using data from the microwave radiometer instrument onboard NASA's Juno spacecraft. Each of the instrument's six channels is sensitive to microwaves from different depths beneath the clouds. Image Credits: NASA/JPL-Caltech/SwRI.

"The closer you get to Jupiter, the weirder it gets," said Heidi Becker, Juno's radiation monitoring investigation lead at JPL. "We knew the radiation would probably surprise us, but we didn't think we'd find a new radiation zone that close to the planet. We only found it because Juno's unique orbit around Jupiter allows it to get really close to the cloud tops during science collection flybys, and we literally flew through it."

The new zone was identified by the Jupiter Energetic Particle Detector Instrument (JEDI) investigation. The particles are believed to be derived from energetic neutral atoms (fast-moving ions with no electric charge) created in the gas around the Jupiter moons Io and Europa. The neutral atoms then become ions as their electrons are stripped away by interaction with the upper atmosphere of Jupiter.

Juno also found signatures of a high-energy heavy ion population within the inner edges of Jupiter's relativistic electron radiation belt -- a region dominated by electrons moving close to the speed of light. The signatures are observed during Juno's high-latitude encounters with the electron belt, in regions never explored by prior spacecraft. The origin and exact species of these particles is not yet understood. Juno's Stellar Reference Unit (SRU-1) star camera detects the signatures of this population as extremely high noise signatures in images collected by the mission's radiation monitoring investigation.

Animation above: This looping animation simulates the motion of clouds in Jupiter's Great Red Spot. The animation was made by applying a wind movement model to a mosaic of JunoCam images. Animation Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Justin Cowart.

To date, Juno has completed eight science passes over Jupiter. Juno's ninth science pass will be on Dec. 16.

Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida, and arrived in orbit around Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,100 miles (3,400 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.

JUNO probe orbiting Jupiter. Animation Credits: NASA/JPL-Caltech

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California.

More information on the Juno mission is available at:

https://www.nasa.gov/juno

https://www.missionjuno.swri.edu

The public can follow the mission on Facebook and Twitter at:

http://www.facebook.com/NASAJuno

http://www.twitter.com/NASAJuno

Images (mentioned), Animations (mentioned), Video (mentioned), Text, Credits:NASA/Dwayne Brown/Laurie Cantillo/Tony Greicius/JPL/DC Agle.

Best regards, Orbiter.ch

Mission Status Update – Cruising Toward Asteroid Bennu

NASA - OSIRIS-REx Mission patch.

Dec. 11, 2017

OSIRIS-REx is continuing outbound cruise operations, en route to arrival in August of 2018 at the asteroid Bennu. The spacecraft is currently 29.6 million miles (47.6 million kilometers) from Earth and is executing a program designed to study and reduce the presence of water on the spacecraft.

During routine in-flight testing of the spacecraft’s thermal properties earlier this year, the mission’s navigation team noticed an unexpected minor acceleration of the spacecraft when the Sample Return Capsule (SRC) was exposed to sunlight. The mission team determined that this small thrust was caused by the outgassing of water that had been adsorbed by the SRC’s heat shield and backshell before launch.  Retention of water in blanketing and other materials – and the subsequent outgassing of this water – occurs with all spacecraft. For OSIRIS-REx, it was determined that when the SRC was exposed to the Sun at a distance of less than 1 Astronomical Unit (1 AU = approximately 93 million miles), this trapped water escaped and imparted a small thrust. While this small thrust would not be a problem for other missions, the gravity at the target asteroid Bennu is low enough that even this small amount of thrust could make orbital operations more difficult for OSIRIS-REx.

Image above: The OSIRIS-REx spacecraft is expected to reach its asteroid destination in 2018. Image Credit: NASA.

To better understand the outgassing effects on the spacecraft’s trajectory – and to bake out much of the remaining water before the spacecraft arrives at Bennu – the OSIRIS-REx mission team designed an outgassing program for execution starting earlier this fall. The choice of timing took into account both the spacecraft’s proximity to the Sun (less than 1 AU) and the fact that there were no science activities planned during this period. The outgassing program is being run concurrently with outbound cruise operations and does not affect the timing of the spacecraft’s arrival at Bennu.

Starting in mid-October, the spacecraft has been placed into various attitudes to expose different parts of the SRC to direct sunlight and initiate outgassing. Priority is given to the portions of the SRC that will face the Sun during asteroid proximity operations. The mission team has been able to detect and measure the rate of outgassing at each attitude and has determined that water is being removed as expected. The goal is to reduce the outgassing to the point where the spacecraft can fly the planned baseline trajectories around Bennu without modifications, and preliminary indications show that the program is progressing toward this goal. The program is scheduled to run through early January 2018.

Related links:

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

Asteroids: https://www.nasa.gov/mission_pages/asteroids/main/index.html

Bennu: https://www.nasa.gov/subject/6880/bennu/

Image (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center, by Nancy Neal Jones.

Greetings, Orbiter.ch

China Launches Communications Satellite for Algeria

CASC - China Aerospace Science and Technology Corporation logo.

Dec. 10, 2017

Long March-3B carrying Alcomsat-1 launch

China successfully launched a communications satellite into a preset orbit from the Xichang Satellite Launch Center in the southwestern province of Sichuan early Monday, as part of a contract for design, construction and launch of the satellite for Algeria. Liftoff took place at 16:40 GMT (11:40 a.m. EST).

China Launches Communications Satellite for Algeria

Alcomsat-1, Algeria first communications satellite, was launched 40 minutes after midnight by a Chinese Long March-3B carrier rocket, making it the 258th flight mission for the Long March rocket series.

The satellite, built for a 15-year service life, was the first cooperative project in aerospace industry between the two countries.

Alcomsat-1 satellite

It will be used by Algeria for television broadcast, emergency communication, distance education, e-governance, enterprise communication services, broadband Internet and satellite-based navigation.

For more information about China Aerospace Science and Technology Corporation (CASC): http://english.spacechina.com/n16421/index.html

Images, Video, Text, Credits: CASC/CCTV+/Günter Space Page/Orbiter.ch Aerospace.

Greetings, Orbiter.ch