ULA Successfully Launches Payload for the NRO

ULA - Atlas V / NROL-55 Mission poster.


Oct. 8, 2015

United Launch Alliance Successfully Launches Payload for the National Reconnaissance Office

Atlas V Rocket also Delivers 13 CubeSats to Orbit

A United Launch Alliance (ULA) Atlas V rocket carrying a payload for the National Reconnaissance Office (NRO) and 13 CubeSats lifted off from Space Launch Complex-3 Oct. 8 at 5:49 a.m. PDT. Designated NROL-55, the mission is in support of national defense. This is ULA’s 10th launch in 2015 and the 101st successful launch since the company was formed in December 2006.

Atlas V rocket carrying NROL-55 & CubeSats launch

“Congratulations on today’s successful launch of NROL-55! ULA is honored to have collaborated with the NRO Office of Space Launch and the Air Force on the integration and launch of the NROL-55 spacecraft to orbit with our Atlas V vehicle,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs. “Launches like this only happen with exceptional teamwork by an extremely talented team and a one-launch-at-a-time focus on mission success.”    

The Atlas V rocket also delivered 13 Government Rideshare Advanced Concepts Experiment (GRACE) CubeSats to orbit. The nine NRO-sponsored CubeSats and four NASA-sponsored CubeSats were mounted to the Aft-Bulkhead Carrier located on the back end of the Centaur upper stage.

“The GRACE CubeSats will perform missions demonstrating tracking technologies, software-defined radio communications and will also conduct other measurements and experiments,” said Sponnick. “We are happy that ULA could play a part in bringing these nano-satellites to orbit along with the NRO payload through a cost-effective rideshare.”

Atlas V NROL-55 Launch Highlights

The 13 CubeSats were developed by Aerospace Corporation, the Army’s Space and Missile Defense Center, Tyvak, SRI International, the University of Alaska-Fairbanks, Salish Kootenai College, AMSAT and the Jet Propulsion Laboratory. Weighing 1-5 kilograms, they are developed, launched and controlled at a fraction of the cost of a typical operating satellite.

The NRO payload and GRACE CubeSats were launched aboard an Atlas V Evolved Expendable Launch Vehicle (EELV) 401 configuration vehicle, which includes a 4-meter-diameter payload fairing. The Atlas booster for this mission was powered by the RD AMROSS RD-180 engine and the Centaur upper stage was powered by the Aerojet Rocketdyne RL10C-1 engine.

A CubeSat (Illustration)

ULA's next launch is the Atlas V Global Positioning System (GPS) IIF-11 satellite for the U.S. Air Force, scheduled for Oct. 30 from Space Launch Complex-41 from Cape Canaveral Air Force Station, Florida.

The EELV program was established by the U.S. Air Force to provide assured access to space for Department of Defense and other government payloads. The commercially developed EELV program supports the full range of government mission requirements, while delivering on schedule and providing significant cost savings over the heritage launch systems.

With more than a century of combined heritage, United Launch Alliance is the nation’s most experienced and reliable launch service provider. ULA has successfully delivered more than 100 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system.

For more information on ULA, visit the ULA website at http://www.ulalaunch.com. Join the conversation at http://www.facebook.com/ulalaunch, http://twitter.com/ulalaunch and http://instagram.com/ulalaunch.

Images, Video, Text, Credits: United Launch Alliance (ULA)/Wikimedia.

Greetings, Orbiter.ch

NASA's Curiosity Rover Team Confirms Ancient Lakes on Mars

NASA - Mars Science Laboratory (MSL) patch.

Oct. 8, 2015

A new study from the team behind NASA's Mars Science Laboratory/Curiosity has confirmed that Mars was once, billions of years ago, capable of storing water in lakes over an extended period of time.

Using data from the Curiosity rover, the team has determined that, long ago, water helped deposit sediment into Gale Crater, where the rover landed more than three years ago. The sediment deposited as layers that formed the foundation for Mount Sharp, the mountain found in the middle of the crater today.

Image above: A view from the "Kimberley" formation on Mars taken by NASA's Curiosity rover. The strata in the foreground dip towards the base of Mount Sharp, indicating flow of water toward a basin that existed before the larger bulk of the mountain formed. Image Credits: NASA/JPL-Caltech/MSSS.

"Observations from the rover suggest that a series of long-lived streams and lakes existed at some point between about 3.8 to 3.3 billion years ago, delivering sediment that slowly built up the lower layers of Mount Sharp," said Ashwin Vasavada, Mars Science Laboratory project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, and co-author of the new Science article to be published Friday, Oct. 9.

The findings build upon previous work that suggested there were ancient lakes on Mars, and add to the unfolding story of a wet Mars, both past and present. Last month, NASA scientists confirmed current water flows on Mars.

"What we thought we knew about water on Mars is constantly being put to the test,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at NASA Headquarters in Washington. "It’s clear that the Mars of billions of years ago more closely resembled Earth than it does today. Our challenge is to figure out how this more clement Mars was even possible, and what happened to that wetter Mars." 

Before Curiosity landed on Mars in 2012, scientists proposed that Gale Crater had filled with layers of sediments. Some hypotheses were "dry," suggesting that sediment accumulated from wind-blown dust and sand. Others focused on the possibility that sediment layers were deposited in ancient lakes.

The latest results from Curiosity indicate that these wetter scenarios were correct for the lower portions of Mount Sharp. Based on the new analysis, the filling of at least the bottom layers of the mountain occurred mostly by ancient rivers and lakes over a period of less than 500 million years.

Image above: An image taken at the "Hidden Valley" site, en-route to Mount Sharp, by NASA's Curiosity rover. A variety of mudstone strata in the area indicate a lakebed deposit, with river- and stream-related deposits nearby.
Image Credits: NASA/JPL-Caltech/MSSS.

"During the traverse of Gale, we have noticed patterns in the geology where we saw evidence of ancient fast-moving streams with coarser gravel, as well as places where streams appear to have emptied out into bodies of standing water," Vasavada said. "The prediction was that we should start seeing water-deposited, fine-grained rocks closer to Mount Sharp. Now that we've arrived, we're seeing finely laminated mudstones in abundance that look like lake deposits."

The mudstone indicates the presence of bodies of standing water in the form of lakes that remained for long periods of time, possibly repeatedly expanding and contracting during hundreds to millions of years. These lakes deposited the sediment that eventually formed the lower portion of the mountain. 

"Paradoxically, where there is a mountain today there was once a basin, and it was sometimes filled with water," said John Grotzinger, the former project scientist for Mars Science Laboratory at the California Institute of Technology in Pasadena, and lead author of the new report. "We see evidence of about 250 feet (75 meters) of sedimentary fill, and based on mapping data from NASA's Mars Reconnaissance Orbiter and images from Curiosity's camera, it appears that the water-transported sedimentary deposition could have extended at least 500 to 650 feet (150 to 200) meters above the crater floor."

Furthermore, the total thickness of sedimentary deposits in Gale Crater that indicate interaction with water could extend higher still, perhaps up to one-half mile (800 meters) above the crater floor.

Above 800 meters, Mount Sharp shows no evidence of hydrated strata, and that is the bulk of what forms Mount Sharp. Grotzinger suggests that perhaps this later segment of the crater's history may have been dominated by dry, wind-driven deposits, as was once imagined for the lower part explored by Curiosity.

Mars Science Laboratory (MSL) or Curiosity rover. Image Credits: NASA/J PL-Caltech

A lingering question surrounds the original source of the water that carried sediment into the crater. For flowing water to have existed on the surface, Mars must have had a thicker atmosphere and warmer climate than has been theorized for the ancient era when Gale Crater experienced the intense geological activity. However, current models of this paleoclimate have, literally, come up dry.

At least some of the water may have been supplied to the lakes by snowfall and rain in the highlands of the Gale Crater rim. Some have made the argument that there was an ocean in the plains north of the crater, but that does not explain how the water managed to exist as a liquid for extended periods of time on the surface.

"We have tended to think of Mars as being simple," Grotzinger mused. "We once thought of the Earth as being simple too. But the more you look into it, questions come up because you're beginning to fathom the real complexity of what we see on Mars. This is a good time to go back to reevaluate all our assumptions. Something is missing somewhere."

More information about Mars Science Laboratory is online at: http://www.nasa.gov/msl

NASA's Mars Science Laboratory Project is using Curiosity to assess ancient habitable environments and major changes in Martian environmental conditions. NASA's Jet Propulsion Laboratory, a division of Caltech, built the rover and manages the project for NASA's Science Mission Directorate in Washington.

Based on a Caltech news release written by Rod Pyle.

Images /mentioned), Text (mentioned), Credits: NASA/JPL/Whitney Clavin.

Greetings, Orbiter.ch

Astronaut brains as beacons for researchers

ISS - International Space Station logo.

8 October 2015

How astronauts adapt to the stresses of living in space is helping researchers to pinpoint the causes of common disorders on Earth.

Upside down or right way up?

From the brain’s point of view, living in space is very stressful. The signals from an astronaut’s body in space go haywire as they float in weightlessness. The inner ear reports that it is falling, but the eyes show that nothing is moving.

As fluid shifts to the head, the brain usually interprets this extra pressure as a sign it is upside down – but in space there is no up or down. The body clock might signal that it is tired after a day’s work on the International Space Station, but astronauts experience 16 sunrises and sunsets every 24 hours.

Spacewalks can be extra stressful

Despite all these conflicting signals the brain adapts and within a few days astronauts float through their home in space as if born there.

The amazing ability of our brains to adapt to new experiences is what makes us survive and thrive, but brains also seem to benefit from the past. Experienced astronauts need less time to readapt to weightlessness than rookies, even if the missions are years apart.

Searching connections

Researchers at the University of Antwerpen, Liege and Leuven in Belgium have devised the ‘Brain-DTI’ study to learn more about how astronauts’ brains adapt to spaceflight.

Before and after their flights, up to 16 astronauts will be put in an advanced MRI scanner. The images show the brain’s neural networks and how the connections change after the astronauts’ experiences in space.

MRI scanner

The research has far to go but it is already revealing some areas of the brain that are involved in adapting to new experiences based on conflicting signals from the body – and pointing to areas of interest for people on Earth.

Research for people closer to Earth

Several common disorders found on the ground arise from the brain not adapting to signals from the body correctly. A type of vertigo, for example, can develop when the brain does not adapt to conflicting signals from the inner ear, much like when an astronaut is in space.

Medical researchers now have a starting point to look for problem areas in the complex brain structure in people who suffer from such disorders.

Principle investigator Professor Floris Wuyts explains: “The research on astronauts is an ethical way to look at people’s brains before and after a stressful incident.

“Ideally, we would have brain scans of people when they were healthy and after they started suffering from a disorder, because then we can see where the changes have taken place. But such an ideal situation does not exist, and neither can we give subjects a traumatic experience on purpose, of course.”

Neural networks shown in MRI scan

For the first time a controlled study using advanced MRI methods is showing researchers where to look in the brain’s complex neural network to target areas for further study and cures.

Floris concludes: “The scans from the astronauts are like lighthouses, illuminating points where problems can be in patients on Earth.”

The Brain-DTI study should finish collecting data in 2018 but the first paper, including also data from recent ESA parabolic flight campaigns, has already been published: http://rd.springer.com/article/10.1007%2Fs00429-015-1054-3

Related links:

University of Antwerpen: http://www.uantwerp.be/aurea

University of Liege: http://www.ulg.ac.be/cms/c_5000/en/home

University of Leuven: http://www.kuleuven.be/english

International Space Station Benefits for Humanity: http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station_Benefits_for_Humanity

European space laboratory Columbus: http://www.esa.int/Our_Activities/Human_Spaceflight/Columbus

Experiment archive: http://eea.spaceflight.esa.int/

Images, Text, Credits: ESA/NASA/DLR/University of Antwerpen.

Greetings, Orbiter.ch

China launches Long March 2D carrying Jilin-1 mission

CASC - China Aerospace Science and Technology Corporation logo.

October 7, 2015

Image above: A Long March 2D rocket carrying the Jilin-1 satellites lifts off from the Jiuquan Satellite Launch Center in northwest China. Image Credits: Xinhua/Zhao Peng.

China launched four satellites to provide photographs to commercial clients while helping with harvest assessment, geological disaster prevention and resource surveys. The launch of the Jilin-1 mission took place at 04:13 UTC on Wednesday, using a Long March-2D launch vehicle from the 603 Launch Pad at the Jiuquan Satellite Launch Center’s LC43.

China launches commercial remote-sensing satellites

The Jilin-1 mission was developed on the China’s Jilin Province and is the country’s first self-developed remote sensing satellite for commercial use. Jilin-1 consists of four satellites, one for high-definition images, one for testing new space technology and another two for video.

Data will be provided to commercial clients to help them forecast and mitigate geological disasters, as well as shorten the time scale for the exploration of natural resources. The satellites were developed by the Chang Guang Satellite Technology Co., Ltd under the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences.

Hight Resolution Video Camera on satellite. Image Credit: CASC

Jilin-1 is a 420 kg high-definition optical satellite with a 0.72 m resolution pan-chromatic camera and 4 m resolution multi-spectral camera. It is equipped with three deployable solar panels for power generation that will be stored in internal batteries. The satellite will operate on a 656 km sun synchronous orbit.

Jilin-1 satellite. Image Credit: CASC

The first phase will see the launch of the first four Jilin-1 satellites. Between 2016 and 2019 there are plans to have 16 satellites in orbit, completing a remote sensing network that will cover the entire globe and will be capable of a three to four hours update in the data provided. From 2020, the plans point to a 60 satellite orbital constellation capable of a 30 minutes update in the data provided.

From 2030 the Jilin constellation will have 138 satellites in orbit, forming a all-day, all-weather, full spectrum acquisition segment data and a capability of observing any global arbitrary point with a 10 minutes revisit capability, providing the world’s highest spatial resolution and time resolution space information products.

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

Images (mentioned), Video, Text, Credits: CASC/China.org.cn/CNTV/Orbiter.ch Aerospace.

Greetings, Orbiter.ch

All Along the Fractures

NASA - Mars Reconnaissance Orbiter (MRO) patch.

Oct. 7, 2015

The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter often takes images of Martian sand dunes to study the mobile soils. These images provide information about erosion and movement of surface material, about wind and weather patterns, even about the soil grains and grain sizes. However, looking past the dunes, these images also reveal the nature of the substrate beneath.

Within the spaces between the dunes, a resistant and highly fractured surface is revealed. The fractured ground is resistant to erosion by the wind, and suggests the material is bedrock that is now shattered by a history of bending stresses or temperature changes, such as cooling, for example.

Alternately, the surface may be a sedimentary layer that was once wet and shrunk and fractured as it dried, like gigantic mud cracks. In either case, the relative small and indistinct fractures have trapped the dark dune sand marching overhead. Now the fractures have become quite distinct, allowing us to examine the orientation and spacing of the fractures to learn more about the processes that formed them.

This view is one image product from HiRISE observation (http://www.uahirise.org/ESP_042223_1890), taken July 30, 2015, at 2:33 p.m. local Mars time, 8.719 degrees north latitude, 67.347 degrees east longitude.

Mars Reconnaissance Orbiter. Image Credit: NASA/JPL-Caltech

HiRISE is one of six instruments on the Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter and collaborates with JPL to operate it.

For more information about Mars Reconnaissance Orbiter (MRO), visit: http://www.nasa.gov/mission_pages/MRO/main/index.html

Images, Text, Credits: NASA/JPL-Caltech/University of Arizona/Caption: Mike Mellon/Sarah Loff.

Greetings, Orbiter.ch

Mysterious Ripples Found Racing Through Planet-forming Disc

ESA - Hubble Space Telescope logo.


7 October 2015

Unique structures spotted around nearby star

Hubble and VLT images of the disc around AU Microscopii

Using images from the NASA/ESA Hubble Space Telescope and ESO’s Very Large Telescope, astronomers have discovered never-before-seen structures within a dusty disc surrounding a nearby star. The fast-moving wave-like features in the disc of the star AU Microscopii are unlike anything ever observed, or even predicted, before now. The origin and nature of these features present a new mystery for astronomers to explore. The results are published in the journal Nature on 8 October 2015.

AU Microscopii, or AU Mic for short, is a young, nearby star surrounded by a large disc of dust [1]. Studies of such debris discs can provide valuable clues about how planets, which form from these discs, are created.

Ground-based view of the sky around the nearby star AU Microscopii

Astronomers have been searching AU Mic’s disc for any signs of clumpy or warped features, as such signs might give away the location of possible planets. And in 2014 they used the  powerful high-contrast imaging capabilities of ESO’s newly installed SPHERE instrument, mounted on the Very Large Telescope for their search — and discovered something very unusual.

“Our observations have shown something unexpected,” explains Anthony Boccaletti of the Observatoire de Paris, France, lead author on the paper. “The images from SPHERE show a set of unexplained features in the disc which have an arch-like, or wave-like, structure, unlike anything that has ever been observed before.”

Zoom on AU Mic

Five wave-like arches at different distances from the star show up in the new images, reminiscent of ripples in water. After spotting the features in the SPHERE data the team turned to earlier images of the disc taken by the NASA/ESA Hubble Space Telescope in 2010 and 2011 to see whether the features were also visible in these [2]. They were not only able to identify the features on the earlier Hubble images — but they also discovered that they had changed over time. It turns out that these ripples are moving — and very fast!

“We reprocessed images from the Hubble data and ended up with enough information to track the movement of these strange features over a four-year period,” explains team member Christian Thalmann (ETH Zürich, Switzerland). “By doing this, we found that the arches are racing away from the star at speeds of up to about 40 000 kilometres/hour!”

The features further away from the star seem to be moving faster than those closer to it. At least three of the features are moving so fast that they could well be escaping from the gravitational attraction of the star. Such high speeds rule out the possibility that these are conventional disc features caused by objects — like planets — disturbing material in the disc while orbiting the star. There must have been something else involved to speed up the ripples and make them move so quickly, meaning that they are a sign of something truly unusual [3].

Mysterious ripples moving through the disc of AU Microscopii

“Everything about this find was pretty surprising!” comments co-author Carol Grady of Eureka Scientific, USA. “And because nothing like this has been observed or predicted in theory we can only hypothesise when it comes to what we are seeing and how it came about.”

The team cannot say for sure what caused these mysterious ripples around the star. But they have considered and ruled out a series of phenomena as explanations, including the collision of two massive and rare asteroid-like objects releasing large quantities of dust, and spiral waves triggered by instabilities in the system’s gravity.

But other ideas that they have considered look more promising.

“One explanation for the strange structure links them to the star’s flares. AU Mic is a star with high flaring activity — it often lets off huge and sudden bursts of energy from on or near its surface,” explains co-author Glenn Schneider of Steward Observatory, USA. “One of these flares could perhaps have triggered something on one of the planets — if there are planets — like a violent stripping of material which could now be propagating through the disc, propelled by the flare’s force.”

“It is very satisfying that SPHERE has proved to be very capable at studying discs like this in its first year of operation,” adds Jean-Luc Beuzit, who is both a co-author of the new study and also led the development of SPHERE itself.

The team plans to continue to observe the AU Mic system with SPHERE and other facilities, including ALMA, to try to understand what is happening. But, for now, these curious features remain an unsolved mystery.

Notes:

[1] AU Microscopii lies just 32 light-years away from Earth. The disc essentially comprises asteroids that have collided with such vigour that they have been ground to dust.

[2] The data were gathered by Hubble’s Space Telescope Imaging Spectrograph (STIS).

[3] The edge-on view of the disc complicates the interpretation of its three-dimensional structure.

Hubblecast 88: Mysterious Ripples Found Racing Through Planet-forming Disc:
http://www.spacetelescope.org/videos/heic1521a/

Notes for editors:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

More information:

This research was presented in a paper entitled “Fast-Moving Structures in the Debris Disk Around AU Microscopii”, to appear in the journal Nature on 8 October 2015.

The international team of astronomers in this study consists of Anthony Boccaletti (Observatoire de Paris, CNRS, France), Christian Thalmann (ETH Zürich, Switzerland), Anne-Marie Lagrange (Université Grenoble Alpes, France; CNRS, IPAG, France), Markus Jansons (Stockholm University, Sweden; Max-Planck-Institut für Astronomie, Germany), Jean-Charles Augereau (Université Grenoble Alpes, France; CNRS, IPAG, France), Glenn Schneider (University of Arizona Tucson, USA), Julien Milli (ESO, Chile; CNRS, IPAG, France), Carol Grady (Eureka Scientific, USA), John Debes (STScI, USA), Maud Langlois (CNRS/ENS-L, France), David Mouillet (Université Grenoble Alpes, France; CNRS, IPAG, France), Thomas Henning (Max-Planck-Institut für Astronomie, Germany), Carsten Dominik (University of Amsterdam, Netherlands), Anne-Lise Maire (INAF–Osservatorio Astronomico di Padova, Italy), Jean-Luc Beuzit (Université Grenoble Alpes, France; CNRS, IPAG, France), Joe Carson (College of Charleston, USA), Kjetil Dohlen (CNRS, LAM, France), Markus Feldt (Max-Planck-Institut für Astronomie, Germany), Thierry Fusco (ONERA, France; CNRS, LAM, France), Christian Ginski (Sterrewacht Leiden, Netherlands), Julien H. Girard (ESO, Chile; CNRS, IPAG, France), Dean Hines (STScI, USA), Markus Kasper (ESO, Germany; CNRS, IPAG, France), Dimitri Mawet (ESO, Chile), Francois Ménard (Universidad de Chile, Chile), Michael Meyer (ETH Zürich, Switzerland), Claire Moutou (CNRS, LAM, France), Johan Olofsson (Max-Planck-Institut für Astronomie, Germany), Timothy Rodigas (Carnegie Institution of Washington, USA), Jean-Francois Sauvage (ONERA, France; CNRS, LAM, France), Joshua Schlieder (NASA Ames Research Center, USA; Max-Planck-Institut für Astronomie, Germany), Hans Martin Schmid (ETH Zürich, Switzerland), Massimo Turatto (INAF–Osservatorio Astronomico di Padova, Italy), Stephane Udry (Observatoire de Genève, Switzerland), Farrokh Vakili (Université de Nice-Sophia Antipolis, France), Arthur Vigan (CNRS, LAM, France; ESO, Chile), Zahed Wahhaj (ESO, Chile; CNRS, LAM, France) and John Wisniewski (University of Oklahoma, USA).

Links:

Release on NASA Hubblesite: http://www.spacetelescope.org/news/heic1521/hubblesite.org/newscenter/archive/releases/2015/36/

Relaese on ESO website: http://www.eso.org/public/news/eso1538/

Related links:

SPHERE instrument: http://www.eso.org/public/teles-instr/vlt/vlt-instr/sphere/

Very Large Telescope (VLT): http://www.eso.org/public/teles-instr/vlt/

Image credit: ESO, NASA & ESA/Digitized Sky Survey 2/Videos: ESO, ESA & NASA/Digitized Sky Survey 2/N. Risinger (skysurvey.org)/Music: Johan Monell.

Best regards, Orbiter.ch

Exoplanet Anniversary: From Zero to Thousands in 20 Years

NASA - Kepler Space Telescope Mission patch.

October 7, 2015

Image above: This year we celebrate the discovery of 51 Pegasi b in October, 1995. This giant planet is about half the size of Jupiter and orbits its star in about four days. '51 Peg' helped launch a whole new field of exploration. Image credits: NASA/JPL-Caltech.

October 6 marks the 20th anniversary of the first discovery of a planet orbiting a sun-like, or "normal," star beyond our solar system. The planet, called 51 Pegasi b, belongs to a class of planets now known as exoplanets. Since that momentous discovery, thousands more exoplanets have been found in our galaxy.

Kepler Space Telescope. Image Credit: NASA

For details about planned public events to mark the occasion, and other related stories and graphics, visit: http://planetquest.jpl.nasa.gov/page/20-years

As of today, there are more than 1,800 confirmed exoplanets. More than 1,000 of these were discovered by NASA's Kepler mission, breaking wide open the field of exoplanet science. Kepler has even identified some planets with Earth-like traits, such as Kepler-452b, a near-Earth-size planet found in the habitable zone of a sun-like star. The habitable zone is the region around a star where temperatures are just right for one of life's essential ingredients -- water -- to pool on a planet's surface.

NASA's funny Exoplanet Travel Posters: http://planetquest.jpl.nasa.gov/exoplanettravelbureau

PSO J318.5-22 - Where the Nightlife Never Ends

 
Poster above: Discovered in October 2013 using direct imaging, PSO J318.5-22 belongs to a special class of planets called rogue, or free-floating, planets. Wandering alone in the galaxy, they do not orbit a parent star. Not much is known about how these planets come to exist, but scientists theorize that they may be either failed stars or planets ejected from very young systems after an encounter with another planet. These rogue planets glow faintly from the heat of their formation. Once they cool down, they will be dancing in the dark. Poster Credits: NASA/JPL.

Experience the Gravity of a Super Earth

 
Poster above: Twice as big in volume as the Earth, HD 40307g straddles the line between "Super-Earth" and "mini-Neptune" and scientists aren't sure if it has a rocky surface or one that's buried beneath thick layers of gas and ice. One thing is certain though: at eight time the Earth's mass, its gravitational pull is much, much stronger. Poster Credits: NASA/JPL.

Relax on Kepler-16b - Where your shadow always has company 

Poster above: Like Luke Skywalker's planet "Tatooine" in Star Wars, Kepler-16b orbits a pair of stars. Depicted here as a terrestrial planet, Kepler-16b might also be a gas giant like Saturn. Prospects for life on this unusual world aren't good, as it has a temperature similar to that of dry ice. But the discovery indicates that the movie's iconic double-sunset is anything but science fiction. Poster Credits: NASA/JPL.

Kepler-186 f - Where the Grass is Always Redder

 
Poster above: Kepler-186f is the first Earth-size planet discovered in the potentially 'habitable zone' around another star, where liquid water could exist on the planet's surface. Its star is much cooler and redder than our Sun. If plant life does exist on a planet like Kepler-186f, its photosynthesis could have been influenced by the star's red-wavelength photons, making for a color palette that's very different than the greens on Earth. This discovery was made by Kepler, NASA's planet hunting telescope. Poster Credits: NASA/JPL.

NASA's Ames Research Center, Moffett Field, California, manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder.

For more information about the Kepler mission, visit: http://www.nasa.gov/kepler

A related feature story about other potentially habitable planets is online at: http://www.jpl.nasa.gov/news/news.php?feature=4666

Images (mentioned), Posters (mentioned), Text, Credits: NASA/JPL/Whitney Clavin.

Best regards, Orbiter.ch