The Milky Way’s Ancient Heart

ESO - European Southern Observatory logo.

12 October 2016

VISTA finds remains of archaic globular star cluster

Variable stars close to the galactic centre

Ancient stars, of a type known as RR Lyrae, have been discovered in the centre of the Milky Way for the first time, using ESO’s infrared VISTA telescope. RR Lyrae stars typically reside in ancient stellar populations over 10 billion years old. Their discovery suggests that the bulging centre of the Milky Way likely grew through the merging of primordial star clusters. These stars may even be the remains of the most massive and oldest surviving star cluster of the entire Milky Way.

A team led by Dante Minniti (Universidad Andrés Bello, Santiago, Chile) and Rodrigo Contreras Ramos (Instituto Milenio de Astrofísica, Santiago, Chile) used observations from the VISTA infrared survey telescope, as part of the Variables in the Via Lactea (VVV) ESO public survey, to carefully search the central part of the Milky Way. By observing infrared light, which is less affected by cosmic dust than visible light, and exploiting the excellent conditions at ESO’s Paranal Observatory, the team was able to get a clearer view of this region than ever before. They found a dozen ancient RR Lyrae stars at the heart of the Milky Way that were previously unknown.

RR Lyrae stars in the constellation of Sagittarius

Our Milky Way has a densely populated centre — a feature common to many galaxies, but unique in that it is close enough to study in depth. This discovery of RR Lyrae stars provides compelling evidence that helps astronomers decide between two main competing theories for how nuclear bulges form [1].

RR Lyrae stars are typically found in dense globular clusters. They are variable stars, and the brightness of each RR Lyrae star fluctuates regularly. By observing the length of each cycle of brightening and dimming in an RR Lyrae, and also measuring the star’s brightness, astronomers can calculate its distance [2].

Wide-field view of the Centre of the Milky Way

Unfortunately, these excellent distance-indicator stars are frequently outshone by younger, brighter stars and in some regions they are hidden by dust. Therefore, locating RR Lyrae stars right in the extremely crowded heart of the Milky Way was not possible until the public VVV survey was carried out using infrared light. Even so, the team described the task of locating the RR Lyrae stars in amongst the crowded throng of brighter stars as “daunting”.

Their hard work was rewarded, however, with the identification of a dozen RR Lyrae stars. Their discovery indicate that remnants of ancient globular clusters are scattered within the centre of the Milky Way’s bulge.

Variable RR Lyrae stars

Rodrigo Contreras Ramos elaborates: “This discovery of RR Lyrae Stars in the centre of the Milky Way has important implications for the formation of galactic nuclei. The evidence supports the scenario in which the nuclear bulge was originally made out of a few globular clusters that merged.”

The theory that galactic nuclear bulges form through the merging of globular clusters is contested by the competing hypothesis that these bulges are actually due to the rapid accretion of gas. The unearthing of these RR Lyrae stars — almost always found in globular clusters — is very strong evidence that part of the Milky Way's nuclear bulge did in fact form through merging. By extension, all other similar galactic bulges may have formed the same way.

Zoom on the galactic centre

Not only are these stars powerful evidence for an important theory of galactic evolution, they are also likely to be over 10 billion years old — the dim, but dogged survivors of perhaps the oldest and most massive star cluster within the Milky Way.

Pan across the galactic centre

Notes:

[1] The nuclear stellar bulge is the compact component in the innermost regions of the Milky Way (and other galaxies) extending to a size of about 400 light-years.

[2] RR Lyrae stars, like some other regular variables such as Cepheids, show a simple relationship between how quickly they change in brightness and how luminous they are. Longer periods mean brighter stars. This period-luminosity relationship can be used to deduce the distance of a star from its period of variation and its apparent brightness.

More information:

This research was presented in a paper to appear in The Astrophysical Journal Letters.

The team is composed of D. Minniti (Instituto Milenio de Astrofísica, Santiago, Chile; Departamento de Física, Universidad Andrés Bello, Santiago, Chile; Vatican Observatory, Vatican City State; Centro de Astrofisica y Tecnologias Afines - CATA), R. Contreras Ramos (Instituto Milenio de Astrofísica, Santiago, Chile;  Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Santiago, Chile), M. Zoccali (Instituto Milenio de Astrofísica, Santiago, Chile; Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Santiago, Chile), M. Rejkuba (European Southern Observatory, Garching bei München, Germany; Excellence Cluster Universe, Garching, Germany), O.A. Gonzalez (UK Astronomy Technology Centre, Royal Observatory, Edinburgh, UK), E. Valenti (European Southern Observatory, Garching bei München, Germany), F. Gran (Instituto Milenio de Astrofísica, Santiago, Chile;  Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Santiago, Chile)

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. 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, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:
Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1636/eso1636a.pdf

Variables in the Via Lactea (VVV) ESO public survey: https://vvvsurvey.org/

VISTA infrared survey telescope: http://www.eso.org/vista/

ESO’s Paranal Observatory: http://www.eso.org/public/teles-instr/paranal/

Images, Text, Credits: ESO/VVV Survey/D. Minniti/IAU and Sky & Telescope/Digitized Sky Survey 2. Acknowledgment: Davide De Martin and S. Guisard (www.eso.org/~sguisard)/Videos: ESO/VVV Survey/D. Minniti/Digitized Sky Survey 2, N. Risinger (skysurvey.org. Acknowledgment: Davide De Martin and S. Guisard (www.eso.org/~sguisard), Music: Johan B. Monell (www.johanmonell.com)/5th Dimension.

Greetings, Orbiter.ch

What to expect from Schiaparelli’s camera

ESA & ROSCOSMOS - ExoMars Mission logo.

12 October 2016

As the ExoMars Schiaparelli module descends onto Mars on 19 October it will capture 15 images of the approaching surface. Scientists have simulated the view we can expect to see from the descent camera.

Schiaparelli will separate from its mothership, the Trace Gas Orbiter, on 16 October, with some six million km still to travel before entering the atmosphere of Mars at 14:42 GMT three days later.

Its descent will take just under six minutes, using a heatshield, parachute, thrusters and a crushable structure for the landing.

Animation above: Simulating Schiaparelli's descent camera view. Images Credits:: NASA/JPL/MRO; simulation: ESA.

Schiaparelli is primarily a technology demonstrator to test entry, descent and landing technologies for future missions and is therefore designed to operate for a only few days.

The small surface science package will take readings of the atmosphere, but there is no scientific camera like those found on other landers or rovers – including the ExoMars rover that is planned for launch in 2020.

The lander does, however, carry ESA’s small, 0.6 kg technical camera, a refurbished spare flight model of the Visual Monitoring Camera flown on ESA’s Herschel/Planck spacecraft to image the separation of the two craft after their joint launch.

Animation above: The Planck-Sylda composite seen receding from Herschel after separation. Animation Credit: ESA.

Its role is to capture 15 black and white images during the descent that will be used to help reconstruct the module’s trajectory and its motion, as well giving context information for the final touchdown site.

The wide, 60º field-of-view will deliver a broad look at the landscape below, to maximise the chances of seeing features that will help to pinpoint the landing site and reveal Schiaparelli’s attitude and position during descent.

Images above: Simulated view of Schiaparelli’s descent images. Images Credits: spacecraft: ESA/ATG medialab; simulated views based on NASA MRO/CTX images (credit: NASA/JPL/MRO); landing ellipse background image: THEMIS daytime infrared map from Mars Odyssey; simulation: ESA.

The camera will start taking images around a minute after Schiaparelli’s front shield is jettisoned, when the module is predicted to be about 3 km above the surface. This will result in images covering about 17 sq km on the surface.

The images will be taken at 1.5 s intervals, ending at an altitude of about 1.5 km, covering an area of roughly 4.6 sq km.

Then, at an altitude of about 1.2 km, the parachute and rear cover will be jettisoned, and the thrusters ignited. The thrusters will cut out just 2 m above the surface, with the module’s crushable structure absorbing the force of impact.

Image above: Schiaparelli’s camera sequence. Image Credits: background map: NASA/JPL/MRO; simulation: ESA.

Schiaparelli will target the centre of a 100 km x 15 km landing ellipse, in a relatively flat area in Meridiani Planum, close to the equator in the southern hemisphere. This region has been imaged extensively from orbit, including by ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter.

To plan for analysing Schiaparelli’s descent, thousands of simulations were made varying the atmospheric conditions and the flight path to the surface. From one such simulation, which touched down at the centre of the landing ellipse, simulated images were then made using data from NASA’s orbiter covering the Meridiani region, as shown here.

In reality, the altitudes at which images are actually taken may vary somewhat, depending on the atmospheric conditions, the final path through the atmosphere and the speed at which Schiaparelli descends.

The real images taken on 19 October will be stored in Schiaparelli’s memory before being beamed up to the Mars Reconnaissance Orbiter and downlinked to Earth on 20 October.

Image above: Schiaparelli descent imaging in context. Image Credits: central region: NASA/JPL/MRO; background image: THEMIS daytime infrared map from Mars Odyssey; simulation: ESA.

More information:

ExoMars is a cooperative project between ESA and Roscosmos. It comprises two missions: the Trace Gas Orbiter and the Schiaparelli entry, descent and landing demonstrator module, which were launched on 14 March 2016, and the ExoMars rover and surface platform, scheduled for launch in 2020.

The first of the real images taken by DECA during Schiaparelli’s descent to the surface on 19 October, are expected to be presented during a press briefing on the morning of 20 October, along with other information confirming the status of the lander, and published on our ESA web channels.

The camera was built by OIP in Belgium.

Related links:

Robotic exploration of Mars: http://exploration.esa.int/

Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

Roscosmos: http://en.federalspace.ru/

ExoMars at IKI: http://exomars.cosmos.ru/

Thales Alenia Space: https://www.thalesgroup.com/en/worldwide/space/space

NASA In 2016 ExoMars orbiter (Electra radio): http://mars.nasa.gov/programmissions/missions/future/exomarsorbiter2016/

Where on Mars?: http://whereonmars.co/

More about...

ExoMars Factsheet: http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_Factsheet

ExoMars frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_frequently_asked_questions

ExoMars brochure: http://www.esa.int/About_Us/ESA_Publications/ESA_Publications_Brochures/ESA_BR-327_EXOMARS_2016

NASA's Mars Reconnaissance Orbiter (MRO): http://mars.nasa.gov/mro/

Images (mentioned), Animations (mentioned), Text, Credits: ESA/Detlef Koschny/Elliot Sefton-Nash/Markus Bauer.

Best regards, Orbiter.ch

Final exams prepare Thomas Pesquet for launch

ESA - Proxima mission logo.

12 October 2016

With a launch planned for the early morning of 16 November, ESA astronaut Thomas Pesquet, NASA astronaut Peggy Whitson and Roscosmos commander Oleg Novitsky face a busy schedule of Soyuz exams this month.

Peggy, Oleg and Thomas in front of Soyuz

The trio will be flying to the International Space Station on a new model of Soyuz ferry designated MS. The MS stands for ‘modernised systems’ and this will be the third launch of the lighter, upgraded Soyuz. A new spacecraft means new flight procedures, so Oleg, Thomas and Peggy have more homework than usual to master the controls.

They passed their first test on 6 October with a manual reentry exam, piloting the craft back to Earth safely in a simulation.

Thomas is the flight engineer, sitting on the left of commander Oleg and acting as co-pilot for launch and return.

Soyuz MS-03 crew

On 13 October the trio will enact a rendezvous and docking with the Space Station in their simulator at Star City near Moscow.

These exams are as faithful to the real thing as possible – everything except the weightlessness, the Station and movement is recreated. The instructors invariably programme emergency scenarios into the mix to make sure the astronauts react accordingly and show they know their stuff.

Thomas Pesquet training in Soyuz simulator

After their second test, the trio have 10 days to prepare for the last stretch: in three days they must pass another rendezvous simulation and an exam on the Station’s Russian segment, ending with the final Soyuz qualification exam on 25 October.

That last exam will see them work through a complete launch and docking dressed in the Sokol suits they will wear in space. To begin, commander Oleg will choose an unmarked envelope that contains the emergency scenarios that will be played out – from a fire in the spacecraft to loss of pressure or problems with the docking mechanism.

Afterwards, Oleg, Peggy and Thomas will pay a traditional tribute to fallen cosmonauts at Moscow’s Red Square before heading to the launch site at Baikonur in Kazakhstan.

Journey to the ISS Part 2: Soyuz rendezvous and docking explained

Thomas says, “These are exciting times and I am privileged to be working with the best instructors and crewmates who inspire confidence at every step of the journey. I cannot wait to be launched be into space with Oleg and Peggy.”

Mission Proxima

Thomas’s Proxima mission includes more than 50 experiments for ESA and France’s CNES space agency, plus many more for Station partners.

Oleg, Peggy and Thomas

Thomas is keen on sharing his experience in the run up to launch and his adventure in space – follow him and the mission via thomaspesquet.esa.int and watch the launch live on the ESA website: http://thomaspesquet.esa.int/

Related links:

ESA Proxima mission: http://www.esa.int/Our_Activities/Human_Spaceflight/Proxima

CNES Proxima website: https://proxima.cnes.fr/

Where is the International Space Station?: http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Where_is_the_International_Space_Station

Images, Text, Credits: ESA/GCTC.

Best regards, Orbiter.ch

Science Flows From Space to Ground and Back

ISS - International Space Station logo.

Oct. 11, 2016

What goes up must come down, the saying goes. Sometimes, what comes down goes up again. That is true for several science investigations on the International Space Station, which led to advances on Earth that will be applied in new ways back in space.

Researchers studied the principles of capillary flow and mechanical forces in the low-gravity environment aboard the station. Back on Earth, that knowledge is being applied to design systems for performing various tests of human health. That work in turn may help advance future human space exploration.

One of Emulate’s Organ-Chip devices. Image Credit: Emulate

Capillary forces involve movement of liquid due not to gravity, but interactions between the molecules of the liquid, and between it and a surface such as a container (think of dipping a paper towel in water). In microgravity, capillary forces are more difficult to control on a larger scale, which presents challenges for handling liquid propellants, thermal control, wastewater management and recycling in space.

Three investigations – CFE, CFE2, and CCF – each examined capillary flows in space to help improve design of these systems. A related investigation looked at wetting – a liquid’s ability to spread across a surface – along significant distances and in unusual container shapes in microgravity.

“Through these investigations, we have learned how to make liquids behave, to go where we want them to go, using passive forces of wetting and surface tension,” said Mark Weislogel, principal investigator for three of the experiments. “Control the container shape, and you can exploit those forces to make all the liquid go where you want and to keep air and liquid in the right place.”

This work inspired the formation of IRPI, an Oregon-based research and development firm specializing in fluid-thermal engineering solutions for aerospace, biomedical, and energy applications. Weislogel serves as vice president and senior scientist at the company.

Now, IRPI is helping to apply those lessons learned in space to a technology developed on Earth by Emulate, Inc. The technology, referred to as a ‘Human Emulation System,’ offers researchers a living biological platform that can be used for predicting human response to diseases, medicines, chemicals and foods. The system includes Organ-Chips, which are micro-engineered environments lined with specific, living human cells and tissues such as lung, liver, brain or kidney. Each chip’s tiny channels reproduce blood and air flow and recreate natural physiology and mechanical forces that cells experience within the human body.

Image above: Capillary forces at work in an investigation on the International Space Station. Image Credit: NASA.

A major challenge with many such micro-engineered systems, however, is controlling the movement and integrity of the liquid. The capillary and wetting investigations in space have been extremely useful in addressing this challenge.

“The people at IRPI are experts at fluid mass transport and how to apply it, and we benefit from their insight into how to more precisely control the biological and biochemical microenvironment inside our Organ-Chips,” said Chris Hinojosa, associate director of discovery at Emulate.

After this science went up into space and came back down to Earth, it now may have new applications back in space.

“The collaboration with IRPI provides an exciting opportunity to use our technology for predicting how different factors – such as varying mechanical forces, inflammation, air quality or radiation – may affect the health of astronauts in the space environment,” Hinojosa said.

“Imagine putting an astronaut’s own cells on one of these chips outside the station or on a probe to Mars,” Weislogel said. “You can, in effect, expose someone to life-threatening conditions and see how they respond without actually putting them in harm’s way.”

Image above: Astronaut Cady Coleman conducting a capillary flow investigation aboard the space station Image Credit: NASA.

Emulate is at the early stages of taking an individual patient’s stem cells and differentiating them to create personalized Organ-Chips for precision medicine and personal health applications on Earth, Hinojosa said, and this collaboration could be used to extrapolate that process into using cells from an astronaut.

“One thing we think is powerful is that you can do experiments on these living systems, these personalized human Organ-Chips, that you wouldn’t be able to conduct on an actual human,” Hinojosa said. “We also can look at response to injury or invasion by, say, lunar-dust, bacteria or virus in real-time, or begin to design individualized drugs and preventative health programs.”

Emulate’s adaptation of the Organ-Chips platform for future research investigations on the space station will further improve its products on Earth.

“Learning something like how to ship this living system up to the space station and conduct automated experiments without affecting the biology will really help us as we begin shipping our lab-ready research products all over the world,” Hinojosa said. “NASA’s expertise on logistics and materials offers a wealth of new information and thinking and, in turn, we can be useful to them in a number of ways, such as providing a new biological platform that can enable a new era of research on human health in space.”

Intenational Space Station (ISS). Image Credit: NASA

The back and forth – or in this case, up and down – creates great potential.

“We know how to control fluids, especially at microscale,” said IRPI president Ryan Jenson. “Emulate really understands the science and NASA understands the impacts of testing in space. As a result, we have fundamental science from space applied in terrestrial fields, then that same technology taken back to space to learn more about astronaut health. Everybody wins.”

Capillary flow experiment

Related links:

Investigation – CFE: http://www.nasa.gov/mission_pages/station/research/experiments/978.html

Investigation – CFE2: http://www.nasa.gov/mission_pages/station/research/experiments/459.html

Investigation – CCF: http://www.nasa.gov/mission_pages/station/research/experiments/303.html

IRPI: http://irpillc.com/

Emulate, Inc.: https://emulatebio.com/

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

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

Images (mentioned), Text, Credits: NASA/JSC/Melissa Gaskill/Kristine Rainey.

Best regards, Orbiter.ch

NASA’s Newest Deep Space Network Antenna is Operational

NASA - DSN Team patch.

Oct. 11, 2016

NASA’s newest Deep Space Network (DSN) antenna began communicating with Mars Odyssey and MAVEN (Mars Atmosphere and Volatile Evolution) on October 1 and is now an officially operational addition to the network.

Deep Space Station - 36 (DSS-36) in Canberra, Australia, is one of four 34 meter (111 foot) Beam Waveguide (BWG) antennas to be built as part of the DSN Aperture Enhancement Project. When completed, the new set of antennas will provide the same, if not higher, sensitivity and received signal power as one of the 70 meter (230 foot) antennas that have been operating for over 50 years.

Image above: Deep Space Station 36 (DSS-36) in Canberra, Australia became operational on October 1. Image Credit: NASA.

These new antennas are important in NASA’s Journey to Mars as they will allow missions, both robotic and human, to uplink and downlink larger amounts of science and telemetry, tracking, and command data back and forth from Earth.

BWG antennas differ from conventional antennas in that the transmission and reception of multiple frequencies is facilitated by the rotation of a mirror situated beneath the antenna, in the pedestal room. The location of sensitive instrumentation and transmitters in the pedestal room rather than in the structure of the antenna makes BWG antennas less complicated and more flexible to maintain than conventional antennas.

The DSN, which has been in operation for over 50 years, provides communication and tracking services to about 35 NASA and non-NASA missions beyond geosynchronous orbit (26,000 miles above the Earth’s surface). Its three Deep Space Communication Complexes located in Goldstone, California; Canberra, Australia; and Madrid, Spain are separated by approximately 120 degrees of longitude to ensure that any spacecraft in deep space can communicate with at least one station at all times as the Earth rotates. NASA has performed reconnaissance on every planet in the solar system; the Deep Space Network was there to provide communication and tracking services to all those missions.

Image above: Deep Space Station 36's (DSS-36) first job was to communicate with Mars Odyssey and MAVEN (Mars Atmosphere and Volatile Evolution). Image Credit: NASA.

Two antennas in Madrid, Spain are currently under construction. DSS-56 is scheduled to be operational in October 2019, while DSS-53 is scheduled to begin operations in October 2020. Canberra’s first new 34 meter BWG, DSS-35, began operations on October 1, 2014. When not needed by a mission for arraying, the 34 meter antennas may support individual spacecraft. Antenna arraying combines the signals received by multiple antennas to function as a single large antenna – in this instance as a 70 meter antenna.

Next month, Robert Lightfoot, NASA Associate Administrator, members from NASA’s Space Communications and Navigation (SCaN) Program Office, the Jet Propulsion Laboratory (JPL), Australia’s Commonwealth Scientific and Industrial Research Organisation, and the US Embassy in Canberra, Australia, will gather at the Canberra Deep Space Communications Complex for the ribbon cutting ceremony of the new antenna.

The Commonwealth Scientific and Industrial Research Organisation performs the day-to-day operations at the Canberra Deep Space Communications Complex. JPL manages the operations and maintenance of the DSN for SCaN.

- Deep Space Network (DSN): http://www.nasa.gov/directorates/heo/scan/services/networks/txt_dsn.html

- Jet Propulsion Laboratory - Deep Space Network: http://deepspace.jpl.nasa.gov/

- Canberra Deep Space Communications Complex: http://www.cdscc.nasa.gov/

- Deep Space Network Aperture Enhancement Project: http://www.nasa.gov/directorates/heo/scan/services/networks/txt_daep.html

- View SCaN Latest News Archive: http://www.nasa.gov/directorates/heo/scan/collection_scan_accordion_archive_1.html

Images (mentioned), Text, Credits: NASA/Michael Blackwood.

Greetings, Orbiter.ch

In Daylight on the Night Side

NASA - Cassini Mission to Saturn patch.

Oct. 11, 2016

NASA's Cassini spacecraft looks down at the rings of Saturn from above the planet's nightside. The darkened globe of Saturn is seen here at lower right, along with the shadow it casts across the rings.

The image shows that even on the planet's night side, the rings remain in sunlight, apart from the portion that lies within Saturn's shadow. The rings also reflect sunlight back onto the night side of the planet, making it appear brighter than it would otherwise appear.

Saturn's small moon Prometheus (53 miles or 86 kilometers across) is faintly visible as a speck near upper left. The shadow of Saturn was once long enough to stretch to the orbit of Prometheus. But as northern summer solstice approaches, Saturn's shadow no longer reaches that far (see PIA20498). So Prometheus will not move into the darkness of the planet's shadow until the march of the seasons again causes the shadow to lengthen.

This view looks toward the sunlit side of the rings from about 41 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Aug. 14, 2016.

The view was obtained at a distance of approximately 870,000 miles (1.4 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 87 degrees. Image scale is 53 miles (86 kilometers) per pixel. Prometheus has been brightened by a factor of two to enhance its visibility.

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

The LISA Pathfinder Science Archive is online

ESA - LISA Pathfinder Mission patch.

10 October 2016

ESA's LISA Pathfinder Science Archive opens its virtual gates to the world. It contains data collected by the satellite during the mission's first few months, covering the nominal operations phase of the LISA Technology Package (LTP) – the European payload on LISA Pathfinder.

Launched on 3 December 2015, LISA Pathfinder reached its operational orbit roughly 1.5 million km from Earth towards the Sun in late January 2016. There, it has been demonstrating technology to observe gravitational waves from space by placing two test masses – a pair of identical gold-platinum cubes, measuring 46 mm and with a mass of 2 kg each – in the most precise free fall ever obtained.

LISA Pathfinder in space. Image Credits: ESA/C. Carreau

After the commissioning phase, science operations with the LTP payload started on 1 March and lasted until 25 June. The baton was then passed to the Disturbance Reduction System, an additional experiment provided by NASA on the LISA Pathfinder satellite, that is currently taking measurements. Operations with the LTP will start again in November, for seven months of the extended mission.

First results based on just two months of science operations showed that LISA Pathfinder exceeded expectations, as the two test masses are falling freely through space under the influence of gravity alone, unperturbed by other external forces, to a precision more than five times better than originally required.

As the LTP consortium's proprietary period on the data has expired, the entire data set – including the telemetry of the satellite from launch until the end of the LTP nominal operations phase – is now being published online so that the worldwide scientific community can access it.

Image above: LISA Pathfinder first results. Image Credits: spacecraft: ESA/ATG medialab; data: ESA/LISA Pathfinder Collaboration.

The archive, which features an intuitive cross-platform web interface with search panels, asynchronous data download in several formats and access to an online help-desk, will be regularly updated with new data releases and results. New users who subscribe to the archive will have access to all downlink products and planning files.

The LISA Pathfinder Science Archive is hosted on ESA's servers at the European Space Astronomy Centre (ESAC) near Madrid, Spain.

Related links:

LISA Pathfinder Science Archive: http://lpf.esac.esa.int/lpfsa/

Related Publications:

Armano, M., et al.: http://sci.esa.int/lisa-pathfinder/57912-armano-et-al/

For more information about LISA Pathfinder, visit: http://sci.esa.int/lisa-pathfinder/

Images (mentioned), Text, Credits: ESA/Paul McNamara/Michele Armano.

Best regards, Orbiter.ch