Herschel links Jupiter’s water to comet impact

ESA - Herschel Mission patch.

23 April 2013

ESA’s Herschel space observatory has solved a long-standing mystery as to the origin of water in the upper atmosphere of Jupiter, finding conclusive evidence that it was delivered by the dramatic impact of comet Shoemaker-Levy 9 in July 1994.

During the spectacular week-long collision, a string of 21 comet fragments pounded into the southern hemisphere of Jupiter, leaving dark scars in the planet’s atmosphere that persisted for several weeks.

The remarkable event was the first direct observation of an extraterrestrial collision in the Solar System. It was followed worldwide by amateur and professional astronomers with many ground-based telescopes and the NASA/ESA Hubble Space Telescope.

Shoemaker-Levy 9 impact site G

ESA’s Infrared Space Observatory was launched in 1995 and was the first to detect and study water in Jupiter’s upper atmosphere. It was widely speculated that comet Shoemaker-Levy 9 may have been the origin of this water, but direct proof was missing.

Scientists were able to exclude an internal source, such as water rising from deeper within the planet’s atmosphere, because it is not possible for water vapour to pass through the ‘cold trap’ that separates the stratosphere from the visible cloud deck in the troposphere below.

Thus the water in Jupiter’s stratosphere must have been delivered from outside. But determining its origin had to wait more than 15 years, until Herschel used its sensitive infrared eyes to map the vertical and horizontal distribution of water’s chemical signature.

Herschel’s observations found that there was 2–3 times more water in the southern hemisphere of Jupiter than in the northern hemisphere, with most of it concentrated around the sites of the 1994 comet impact. Additionally, it is only found at high altitudes.

 Water in Jupiter’s atmosphere

“Only Herschel was able to provide the sensitive spectral imaging needed to find the missing link between Jupiter’s water and the 1994 impact of comet Shoemaker-Levy 9,” says Thibault Cavalié of the Laboratoire d’Astrophysique de Bordeaux, lead author of the paper published in Astronomy and Astrophysics.

“According to our models, as much as 95% of the water in the stratosphere is due to the comet impact.”

Another possible source of water would be a steady rain of small interplanetary dust particles onto Jupiter. But, in this case, the water should be uniformly distributed across the whole planet and should have filtered down to lower altitudes.

ESA’s Herschel Infrared Space Observatory

Also, one of Jupiter’s icy moons could deliver water to the planet via a giant vapour torus, as Herschel has seen from Saturn’s moon Enceladus, but this too has been ruled out. None of Jupiter’s large moons is in the right place to deliver water to the locations observed.

Finally, the scientists were able to rule out any significant contributions from recent small impacts spotted by amateur astronomers in 2009 and 2010, along with local variations in the temperature of Jupiter’s atmosphere.

Shoemaker-Levy 9 is the only likely culprit.

“All four giant planets in the outer Solar System have water in their atmospheres, but there may be four different scenarios for how they got it,” says Dr Cavalié. “For Jupiter, it is clear that Shoemaker-Levy 9 is by far the dominant source, even if other external sources may contribute also.”

Comet Shoemaker-Levy 9 approaches Jupiter

“Thanks to Herschel’s observations, we have now linked a unique comet impact – one that was followed in real time and which captured the public’s imagination – to Jupiter’s water, finally solving a mystery that has been open for nearly two decades,” adds Göran Pilbratt, ESA’s Herschel project scientist.

The observations made in this study foreshadow those planned for ESA’s future Jupiter Icy moons Explorer mission launching towards the Jovian system in 2022, where it will map the distribution of Jupiter’s atmospheric ingredients in even greater detail.

Notes for Editors:

“The spatial distribution of water in the stratosphere of Jupiter from Herschel-HIFI and –PACS observations,” by T. Cavalié et al. is published in Astronomy & Astrophysics, 553, A21, May 2013.

The observations were obtained under the Herschel Guaranteed Time Key Programme “Water and related chemistry in the Solar System”. HIFI observations were taken in July 2010 and PACS observations were made in October 2009 and December 2010.  The results were complemented with data on the stratospheric temperature of Jupiter taken at NASA’s Infrared Telescope Facility taken during the same period.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Related links:

Herschel: ESA's giant infrared observatory: http://www.esa.int/Our_Activities/Space_Science/Herschel

Online Showcase of Herschel Images OSHI: http://oshi.esa.int/

Herschel operations: http://www.esa.int/Our_Activities/Operations/Herschel_operations

This article in depth: http://sci.esa.int/jump.cfm?oid=51720

Read science paper: http://www.aanda.org/10.1051/0004-6361/201220797

Herschel Science Centre: http://herschel.esac.esa.int/

Images, Text, Credits: ESA / R. Evans, J. Trauger, H. Hammel and the HST Comet Science Team / Water map: ESA/Herschel/T. Cavalié et al.; Jupiter image: NASA/ESA/Reta Beebe (New Mexico State University) / Comet Shoemaker-Levy 9 approaches Jupiter: NASA, ESA, H. Weaver & E. Smith (STScI) and J. Trauger & R. Evans (Jet Propulsion Laboratory).

Best regards, Orbiter.ch

Concept mission to clear a defunct satellite from orbit

ESA - European Space Agency patch.

23 April 2013

 Cleaning space

Artist’s concept showing how a defunct satellite could be grappled for a controlled reentry into Earth’s atmosphere, where it would burn up and be destroyed harmlessly.

This is one of several concepts for clearing dead satellites from orbit being studied by space agencies and industry across Europe.

Hundreds of experts from across the globe are meeting at Europe’s largest-ever debris forum this week to share research findings and discuss potential solutions.

Satellite operators worldwide, including those flying telecom, weather, navigation, broadcast and climate-monitoring missions, are focusing their efforts on controlling space debris.

Scientists estimate the level of space debris orbiting Earth to be around 29 000 objects larger than 10 cm, 670 000 pieces larger than 1 cm and more than 170 million above 1 mm – and any one of these could seriously damage a spacecraft.

Cleaning space above our atmosphere is a strategic goal for ESA.

Background:
   
About debris: http://www.esa.int/Our_Activities/Operations/Space_Debris/Cleaning_space
   
Analysis and prediction: http://www.esa.int/Our_Activities/Operations/Space_Debris/Analysis_and_prediction
    
Scanning & observing: http://www.esa.int/Our_Activities/Operations/Space_Debris/Scanning_observing
   
Re-entry and collision avoidance: http://www.esa.int/Our_Activities/Operations/Space_Debris/Re-entry_and_collision_avoidance
   
Mitigating space debris generation: http://www.esa.int/Our_Activities/Operations/Space_Debris/Mitigating_space_debris_generation
   
Debris removal: http://www.esa.int/Our_Activities/Operations/Space_Debris/Debris_removal
   
Hypervelocity impacts and protecting spacecraft: http://www.esa.int/Our_Activities/Operations/Space_Debris/Hypervelocity_impacts_and_protecting_spacecraft
   
International cooperation: http://www.esa.int/Our_Activities/Operations/Space_Debris/International_cooperation

Images, Text, Credits: ESA / Mixed-Reality Communication GmbH.

Greetings, Orbiter.ch

Taking two bites at ocean salinity?

ESA - SMOS Mission logo / NASA - Aquarius Mission patch.

22 April 2013

The saltiness of the oceans is being closely monitored from space by both ESA’s SMOS and NASA’s Aquarius missions, but in slightly different ways. By joining forces, researchers are exploiting these complementary missions to benefit climate science even further.

Freshwater plume from SMOS (top) Aquarius (bottom)

Everyone knows that seawater is salty, but it isn’t that obvious that the concentration of salt – the salinity – of the surface waters of the world’s oceans varies considerably with location and season.

Salinity is controlled largely by the balance between evaporation and precipitation, so it is an important component of Earth’s water cycle and closely coupled to weather and climate. It is also an important driver in ocean circulation, which in turn, is crucial in moderating the climate.

In fact, ocean salinity is an 'essential climate variable' – a key parameter of climate change.

SMOS in orbit

Until the launch of SMOS in 2009 and Aquarius in 2011, global data on this important variable were simply not available. Scientists need this information to feed into the mathematical models they use to understand the complexities of the exchange processes between Earth’s surfaces and the atmosphere.

Thanks to both missions, these much-needed data are leading to a better understanding of the water cycle, how the ocean works and how salinity is linked to weather and climate.

ESA’s SMOS satellite and NASA’s Aquarius sensor, carried on Argentina’s SAC-D satellite, both use an L-band radiometer to map ocean salinity but offer different resolutions and revisit times.

Salinity from SMOS and Aquarius

For example, Aquarius provides better ‘pixel’ accuracy than SMOS, whereas SMOS provides higher revisit times and spatial resolution.

While it has been shown clearly that their datasets agree and provide similar information, the differences in the data can be exploited to yield even more detail about variations in the salinity of our oceans.

Aquarius in orbit

For instance, the animation above shows the freshwater plume in the Pacific Ocean west of Panama as seen from both missions. This fresh pool is a consequence of heavy summer rains over Central America. Wind is also an important factor in the salinity of the water in this region.

Related links:

SMOS: http://www.esa.int/Our_Activities/Observing_the_Earth/SMOS/

Access SMOS data: http://earth.esa.int/SMOS/

Essential climate variable: http://www.wmo.int/pages/prog/gcos/index.php?name=EssentialClimateVariables

SMOS & Aquarius science workshop: http://www.smosaquarius2013.org/

Aquarius: http://aquarius.nasa.gov/index.html

Ifremer: http://www.salinityremotesensing.ifremer.fr/home

SMAP: http://smap.jpl.nasa.gov/

CONAE: http://www.conae.gov.ar/eng/

Images, Video, Text, Credits: ESA / P. Carril / NASA / IFREMER / ESR.

Best regards, Orbiter.ch

NASA Successfully Launches Three Smartphone Satellites

NASA logo.

April 22, 2013

Three smartphones destined to become low-cost satellites rode to space Sunday aboard the maiden flight of Orbital Science Corp.'s Antares rocket from NASA's Wallops Island Flight Facility in Virginia.

The trio of "PhoneSats" is operating in orbit, and may prove to be the lowest-cost satellites ever flown in space. The goal of NASA's PhoneSat mission is to determine whether a consumer-grade smartphone can be used as the main flight avionics of a capable, yet very inexpensive, satellite.

NASA PhoneSat 1.0

Transmissions from all three PhoneSats have been received at multiple ground stations on Earth, indicating they are operating normally. The PhoneSat team at the Ames Research Center in Moffett Field, Calif., will continue to monitor the satellites in the coming days. The satellites are expected to remain in orbit for as long as two weeks.

"It's always great to see a space technology mission make it to orbit -- the high frontier is the ultimate testing ground for new and innovative space technologies of the future," said Michael Gazarik, NASA's associate administrator for space technology in Washington.

"Smartphones offer a wealth of potential capabilities for flying small, low-cost, powerful satellites for atmospheric or Earth science, communications, or other space-born applications. They also may open space to a whole new generation of commercial, academic and citizen-space users."

PhoneSat 1.0 design

Satellites consisting mainly of the smartphones will send information about their health via radio back to Earth in an effort to demonstrate they can work as satellites in space. The spacecraft also will attempt to take pictures of Earth using their cameras. Amateur radio operators around the world can participate in the mission by monitoring transmissions and retrieving image data from the three satellites. Large images will be transmitted in small chunks and will be reconstructed through a distributed ground station network. More information can found at: http://www.phonesat.org

NASA's off-the-shelf PhoneSats already have many of the systems needed for a satellite, including fast processors, versatile operating systems, multiple miniature sensors, high-resolution cameras, GPS receivers and several radios.

NASA engineers kept the total cost of the components for the three prototype satellites in the PhoneSat project between $3,500 and $7,000 by using primarily commercial hardware and keeping the design and mission objectives to a minimum. The hardware for this mission is the Google-HTC Nexus One smartphone running the Android operating system.

PhoneSat 1.0 assembly

NASA added items a satellite needs that the smartphones do not have -- a larger, external lithium-ion battery bank and a more powerful radio for messages it sends from space. The smartphone's ability to send and receive calls and text messages has been disabled.

Each smartphone is housed in a standard cubesat structure, measuring about 4 inches square. The smartphone acts as the satellite's onboard computer. Its sensors are used for attitude determination and its camera for Earth observation.

For more about information about NASA's Small Spacecraft Technology Program and the PhoneSat mission, visit: http://www.nasa.gov/smallsats

The PhoneSat mission is a technology demonstration project developed through the agency's Small Spacecraft Technology Program, part of NASA's Space Technology Mission Directorate. The directorate is innovating, developing, testing and flying hardware for use in future science and exploration missions. NASA's technology investments provide cutting-edge solutions for our nation's future. For more information about NASA's Space Technology Mission Directorate, visit: http://www.nasa.gov/spacetech

Images, Text, Credit: NASA.

Cheers, Orbiter.ch

Facing Enceladus

NASA / ESA - Cassini Mission to Saturn patch.

22 April 2013

 Facing Enceladus

A patchwork network of frozen ridges and troughs cover the face of Enceladus, Saturn’s most enigmatic of icy moons.

This face-on colour view of Enceladus was taken by the international Cassini spacecraft on 31 January 2011, from a distance of 81 000 km, and processed by amateur astronomer Gordan Ugarković.

Saturn’s imposing gravitational pull massages the moon’s icy shell, buckling it into ridges that tower over deep fractures.

The cavernous scar towards the south, which may plunge to depths of a kilometre, cuts across other features, indicating its relative youth. By contrast, the cratered region to the north, which is split in two by a vast swath of grooved terrain, hints at a much older surface that has so far escaped the resurfacing experienced elsewhere.

Enceladus is a moon bursting at the seams: along the southern hemisphere, plumes of ice particles mixed with water vapour, salts and organic material jet from fissures nicknamed ‘tiger stripes’.

Some of the plumes pump their spray into space at speeds of over 2000 km/h, injecting particles into Saturn’s E-ring.

The chemistry of the plumes suggests that there may be a liquid ocean hidden beneath the moon’s surface that could provide a suitable habitat for life.

Cassini spacecraft Enceladus flyby

A thin crescent of Enceladus is illuminated by incident sunlight coming from the right hand side of this frame, including sunlight that has been reflected by Saturn onto the moon.

The Cassini–Huygens mission is a cooperative project of NASA, ESA and ASI, the Italian space agency. NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington DC, USA.

Related links:

At Saturn and Titan: http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Cassini-Huygens in depth: http://sci.esa.int/huygens

Images, Text, Credits: ESA / NASA / JPL-Caltech / SSI / G. Ugarković.

Greetings, Orbiter.ch

NASA Partner Orbital Sciences Test Launches Antares Rocket

NASA / ORBITAL - Antares A One Mission patch.

April 21, 2013

 The Antares rocket clears the launch pad on its way to orbit. Credit: NASA

NASA commercial space partner Orbital Sciences Corporation Sunday launched its Antares rocket at 5:00 p.m. EDT from the new Mid-Atlantic Regional Spaceport Pad-0A at the agency's Wallops Flight Facility in Virginia.

Successful Launch for Antares

The test flight was the first launch from the pad at Wallops and was the first flight of Antares, which delivered the equivalent mass of a spacecraft, a so-called mass simulated payload, into Earth's orbit.

"Today's successful test marks another significant milestone in NASA's plan to rely on American companies to launch supplies and astronauts to the International Space Station, bringing this important work back to the United States where it belongs," said NASA Administrator Charles Bolden. "Congratulations to Orbital Sciences and the NASA team that worked alongside them for the picture-perfect launch of the Antares rocket. In addition to providing further evidence that our strategic space exploration plan is moving forward, this test also inaugurates America's newest spaceport capable of launching to the space station, opening up additional opportunities for commercial and government users.

The Cygnus spacecraft is designed to carry cargo and experiments for ISS. Image credit: NASA

"President Obama has presented a budget for next year that ensures the United States will remain the world leader in space exploration, and a critical part of this budget is the funding needed to advance NASA's commercial space initiative. In order to stop outsourcing American space launches, we need to have the President's budget enacted. It's a budget that's good for our economy, good for the U.S. Space program -- and good for American taxpayers."

The test of the Antares launch system began with the rocket's rollout and placement on the launch pad April 6, and culminated with the separation of the mass simulator payload from the rocket.

The completed flight paves the way for a demonstration mission by Orbital to resupply the space station later this year. Antares will launch experiments and supplies to the orbiting laboratory carried aboard the company's new Cygnus cargo spacecraft through NASA's Commercial Resupply Services (CRS) contract.

"Today's successful test flight of Orbital Sciences' Antares rocket from the spaceport at Wallops Island, Virginia, demonstrates an additional private space-launch capability for the United States and lays the groundwork for the first Antares cargo mission to the International Space Station later this year," said John Holdren, director of the Office of Science and Technology Policy. "The growing potential of America's commercial space industry and NASA's use of public-private partnerships are central to President Obama's strategy to ensure U.S. leadership in space exploration while pushing the bounds of scientific discovery and innovation in the 21st century. With NASA focusing on the challenging and exciting task of sending humans deeper into space than ever before, private companies will be crucial in taking the baton for American cargo and crew launches into low-Earth orbit.

Antares description. Image credit: Orbital

"I congratulate Orbital Sciences and the NASA teams at Wallops, and look forward to more groundbreaking missions in the months and years ahead."

Orbital is building and testing its Antares rocket and Cygnus spacecraft under NASA's Commercial Orbital Transportation Services (COTS) program. After successful completion of a COTS demonstration mission to the station, Orbital will begin conducting eight planned cargo resupply flights to the orbiting laboratory through NASA's $1.9 billion CRS contract with the company.

NASA initiatives, such as COTS, are helping to develop a robust U.S. commercial space transportation industry with the goal of achieving safe, reliable and cost-effective transportation to and from the International Space Station and low-Earth orbit. NASA's Commercial Crew Program also is working with commercial space partners to develop capabilities to launch U.S. astronauts from American soil in the next few years.

For more information about the upcoming Orbital test flights, and links to NASA's COTS and Commercial Crew programs, visit: http://www.nasa.gov/orbital

For information on Orbital's Antares launch vehicle, visit: http://www.orbital.com/Antares

Images, Text, Video, Credits: NASA / Trent J. Perrotto / Johnson Space Center / Josh Byerly / Orbital Sciences Corp.

Best regards, Orbiter.ch

CME Headed Toward Planet Mercury

NASA - STEREO Mission logo / NASA / ESA - SOHO Mission patch.

April 21, 2013

The same region of the sun erupted with another coronal mass ejection (CME) at 3:54 a.m. on April 21, 2013. Experimental NASA research models show the CME left the sun at speeds of 550 miles per second. The models show that the CME will also pass by NASA’s Messenger and the flank of the CME may graze STEREO-A. The Messenger and STEREO mission operators have been notified. There may be some particle radiation associated with this event, which in the worst case scenarios can impact computer electronics on board interplanetary spacecraft. If warranted, operators can put spacecraft into safe mode to protect the instruments from the solar material.

(Click on the image for enlarge)

This image of a coronal mass ejection (CME) was captured at 7:30 a.m. EDT on April 20, 2013. The CME is headed in the direction of Mercury. The large bright spot on the left is Venus. Credit: ESA & NASA / SOHO.

On April 20, 2013, at 2:54 a.m. EDT, the sun erupted with a coronal mass ejection (CME), a solar phenomenon that can send billions of tons of solar particles into space that can affect electronic systems in satellites. Experimental NASA research models show that the CME left the sun at 500 miles per second and is not Earth-directed. However, it may pass by NASA's Messenger and STEREO-A satellites, and their mission operators have been notified. There is, however, no particle radiation associated with this event, which is what would normally concern operators of interplanetary spacecraft since the particles can trip computer electronics on board. When warranted, NASA operators can put spacecraft into safe mode to protect the instruments from the solar material.

What is a solar flare? What is a CME?

For answers to these and other space weather questions, please visit the Spaceweather Frequently Asked Questions page: http://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html

Related Links:

View Past Solar Activity: http://www.nasa.gov/mission_pages/sunearth/multimedia/Solar-Events.html

Image (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Karen C. Fox.

Greetings, Orbiter.ch