Posted on by Jason Major

Saturn’s Fluctuating F Ring

Bright clumps of material spotted within Saturn’s ropy F ring (NASA/JPL/SSI)

Released today, this image acquired by NASA’s Cassini spacecraft shows some interesting structures forming within Saturn’s thinnest but most dynamic ring.

Of Saturn’s countless ring structures the F ring may very well be the most dynamic, if not the most fascinating. Orbiting Saturn just outside the edge of the A ring at a distance of 140,000 km (87,000 miles), the F ring is a hazy, ropy band of fine ice particles that shift, twist and occasionally gather into bright clumps… only to drift apart once more.

The F ring can range in width from 30 to 500 km (20-500 miles), depending on what’s going on in and outside of it.

The image above, originally captured by Cassini on June 28 and released today by the Cassini Imaging Central Laboratory for Operations (CICLOPS), shows a particularly bright clump of material at the outer edge of the F ring, as well as some finer structures and streamers forming within the inner bands. Due to the lighting geometry its thought that the clumps are mostly composed of dusty material.

Detail of the ghostly F ring structures (NASA/JPL/SSI)

The features seen here are likely due to the ring’s interactions with passing shepherd moons — such as the 148-km-wide Prometheus — or with small moonlets embedded within the ring itself. Mostly made of fine particles of dust and ice smaller than those found in smoke, the material orbiting within the F ring is extremely susceptible to external gravitational influences.

Original image scale is 4 km (3 miles) per pixel.

See more images from the entire Cassini mission on the CICLOPS site here (and for a look at more interesting ring dynamics check out these recent Cassini images of my personal favorite moon, Daphnis.)

 

Posted on by Jenny Winder

GOCE – How Low Can It Go?

Caption: GOCE over ice. Credits: ESA – AOES Medialab

Since March 2009, the European Space Agency (ESA) mission, Gravity field and steady-state Ocean Circulation Explorer (GOCE) has been orbiting Earth. It carries highly sensitive instrumentation able to detect tiny variations in the pull of gravity across the surface of the planet, allowing it to map our planet’s gravity with unrivaled precision, producing the most accurate gravity map of Earth. With the planned mission completed, the fuel consumption has been much lower than anticipated, enabling ESA to extend GOCE’s life and put it into an even lower orbit, improving the quality of the gravity model.

The GOCE spacecraft was designed to fly low and has spent most of its mission roughly 500km below most other Earth-observing missions, at an altitude of 255km. ESA’s Earth Scientific Advisory Committee recommended lowering the orbit by 20km at a rate of about 300m per day, starting in August. After coming down by 8.6 km, the satellite’s performance and orbit were assessed. Now, GOCE is again being lowered while continuing its gravity mapping. It is expected to reach 235 km by February.

Decreasing the altitude increases the spatial resolution and the precision of the data. The expected increase in data quality is so high (possibly 35%) that scientists are calling it GOCE’s ‘second mission. Volker Liebig, ESA’s Director of Earth Observation Programmes has said “What the team of ESA engineers is now doing has not been done before and it poses a challenge. But it will also trigger new research in the field of gravity based on the high-resolution data we are expecting.”

Caption: The image on the left shows GOCE’s gravity measurements over northern Europe, acquired from its previous altitude. The image on the right depicts the expected measurements over the same area after the satellite has been lowered. Credits: ESA / GOCE+ Theme 2

The first ‘geoid’ based on GOCE’s gravity measurements was unveiled in June 2010. It is a crucial reference for conducting precise measurements of ocean circulation, sea-level change and ice dynamics. The mission has also been studying air density and wind in space, and its data was recently used to produce the first global high-resolution map of the boundary between Earth’s crust and mantle, called the Mohorovicic, or “Moho” discontinuity.

As the orbit drops, atmospheric drag increasingly pulls the satellite towards Earth, so GOCE has to use the tiny thrust of its ion engine to continuously compensate for any drag to stay aloft and maintain the stability it needs to measure Earth’s gravity. GOCE has enough xenon fuel for another 50 weeks of operations. When the fuel runs out the satellite will be pulled into the deep atmosphere where it will burn up

Find out more about the GOCE mission here

Posted on by Carnival of Space

Carnival of Space #276

This week’s Carnival of Space is hosted by Universe Today’s very own John Williams at his very own Starry Critters website.

Click here to read Carnival of Space #276.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

Posted on by Nancy Atkinson

Brighter Than the Moon: Camera Captures Brilliant Leonid Fireball

The Leonid Meteor shower is usually notorious for the bright fireballs it can produce, but this fireball exploded with unexpected brilliance. Fortunately, an all-sky camera captured the event. NASA said there were numerous reports of a bright fireball over northwest Alabama on Sunday, Nov. 18 at approximately 7:30 p.m. EST. A check of the southeastern cameras operated by NASA’s Meteoroid Environment Office recorded the fireball, and its outburst was brighter than the Moon. If anyone happened to see this or capture anything similar with your camera, let us know!

Astrophotographers did manage to get some images of the Leonids over the weekend — which, other than this bright fireball — seemed to be relatively quiet. See images below:

A Leonid meteor over Trá Mór, Spiddal, Ireland on November 18, 2012 at 4:45 am local time. Credit: Trevor Durity

Trevor Durity captured a small Leonid fireball in the wee hours of the morning on Nov. 18. “One of the few meteors I saw,” Trevor wrote on Flickr. “Pure luck to have caught it … Appeared at first like a very bright shooting star – went about 10 degrees and blew up.”

Also in the picture are the Gemini twins Castor and Pollux to the top middle, M44 the Beehive Cluster to the lower left; and the bright star Procyon to the lower right of the twins, and Leo the Lion on the left hand side of the picture.

A lone Leonid was captured over Donegal, Ireland. Credit: Brendan Alexander.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Posted on by Nancy Atkinson

Stunning New Timelapse: Storms and Stars at Joshua Tree

Here’s another gorgeous timelapse by Gavin Heffernan, who returned to Joshua Tree National Park in California for his third look at the incredible night sky. “It was an epic night,” Gavin told UT, “with storms at first, then some of the clearest skies I’ve ever seen.”

The sky is ablaze with activity; the rolling storm, the Milky Way in all its glory, plus meteors, satellites and aircraft passing overhead. Gavin and his Sunchaser Pictures team shot the footage with a Canon 7D and Canon 5D, with a 24mm/1.4 lens and a 28mm/1.8. Most intervals are 25 seconds, except the 1st, which is 30 second, Gavin said.

If you like this one, take a look at Gavin’s first and second visits to Joshua Tree, too.

JOSHUA TREE JOURNEY 3: STORM from Sunchaser Pictures on Vimeo.

Posted on by Nancy Atkinson

Surreal Images of Soyuz Landing in the Dark

The Soyuz TMA-05M spacecraft is seen shortly after it landed on November 19, 2012 with the Expedition 33 crew. Credit: NASA/Bill Ingalls.

The Soyuz TMA-05M spacecraft carrying Expedition 33 Commander Suni Williams and Flight Engineers Yuri Malenchenko and Aki Hoshide landed in the steppe of Kazakhstan, and even though it was 7:56 a.m. Kazakhstan time (01:56 UTC Nov. 19, 8:56 p.m. EST on Nov. 18), it was still dark near the remote northern latitude town of Arkalyk (50°14’53.16″N). This was the first pre-dawn landing in darkness for a station crew since April 9, 2006, when Expedition 12 crew members returned. The overhead pictures from the scene have a surreal feel to them.

A problem with the Soyuz’ parachute – it deployed about 5 seconds later than planned – caused the crew to land several miles away from the planned landing site, but a Russian recovery team and NASA personnel reached the landing site by helicopter shortly afterward to assist the crew in getting out of the spacecraft, which landed on its side. Frigid temperatures greeted the crew when the hatch was opened; it was about -12 C (12 F), said NASA TV commentator Rob Navias.

Another overhead view of the Soyuz. Note the soot on the snow from the landing. Credit: Ria Novosti//Maxim Shipenkov. See a slideshow of images here.

The return of Williams, Hoshide and Malenchenko wraps up 127 days in space for the three since their launch from the Baikonur Cosmodrome in Kazakhstan on July 15, including 125 days spent aboard the International Space Station.

Screenshot from NASA TV of the post-landing activities.

Earlier the crew bid farewell to their fellow crewmates, NASA astronaut Kevin Ford and Russian cosmonauts Evgeny Tarelkin and Oleg Novitskiy, and closed the hatches between the spacecraft at 2:15 p.m. When the Soyuz undocked from the station’s Rassvet module at 5:26 p.m. it marked the end of Expedition 33 and the beginning of Expedition 34 under the command of Ford.

The Expedition 33 crew sit in chairs outside the Soyuz Capsule just minutes after they landed in a remote area outside the town of Arkalyk, Kazakhstan, on Monday, Nov. 19, 2012. Credit: NASA/Bill Ingalls.

Three additional Expedition 34 flight engineers — NASA astronaut Tom Marshburn, Canadian Space Agency astronaut Chris Hadfield, and Russian Federal Space Agency cosmonaut Roman Romanenko — are scheduled to launch from Baikonur Dec. 19 and dock to the station two days later for a five-month stay. Hadfield will become the first Canadian to command the station when Ford, Novitskiy and Tarelkin depart in March, marking the start of Expedition 35.

Here’s the video of the landing, although there is no actual footage of the Soyuz touching down, since it was dark and the spacecraft landed well away from the planned landing spot.

Posted on by Ken Kremer

Can Humans Live on Mars?

Image caption: Curiosity is taking the first ever radiation measurements from the surface of another planet in order to determine if future human explorers can live on Mars – as she traverses the terrain of the Red Planet. Curiosity is looking back to her rover tracks and the foothills of Mount Sharp and the eroded rim of Gale Crater in the distant horizon on Sol 24 (Aug. 30, 2012). This panorama is featured on PBS NOVA ‘Ultimate Mars Challenge’ documentary which premiered on PBS TV on Nov. 14. RAD is located on the rover deck in this colorized mosaic stitched together from Navcam images by the image processing team of Ken Kremer & Marco Di Lorenzo. Credit: NASA / JPL-Caltech / Ken Kremer / Marco Di Lorenzo

Metallic robots constructed by ingenious humans can survive on Mars. But what about future human astronauts?

NASA’s plucky Mars Exploration Rover Opportunity has thrived for nearly a decade traversing the plains of Meridiani Planum despite the continuous bombardment of sterilizing cosmic and solar radiation from charged particles thanks to her radiation hardened innards.

How about humans? What fate awaits them on a bold and likely year’s long expedition to the endlessly extreme and drastically harsh environment on the surface of the radiation drenched Red Planet – if one ever gets off the ground here on Earth? How much shielding would people need?

Answering these questions is one of the key quests ahead for NASA’s SUV sized Curiosity Mars rover – now 100 Sols, or Martian days, into her 2 year long primary mission phase.

Preliminary data looks promising.

Curiosity survived the 8 month interplanetary journey and the unprecedented sky crane rocket powered descent maneuver to touch down safely inside Gale Crater beside the towering layered foothills of 3 mi. (5.5 km) high Mount Sharp on Aug. 6, 2012.

Now she is tasked with assessing whether Mars and Gale Crater ever offered a habitable environment for microbial life forms – past or present. Characterizing the naturally occurring radiation levels stemming from galactic cosmic rays and the sun will address the habitability question for both microbes and astronauts. Radiation can destroy near-surface organic molecules.

Researchers are using Curiosity’s state-of-the-art Radiation Assessment Detector (RAD) instrument to monitor high-energy radiation on a daily basis and help determine the potential for real life health risks posed to future human explorers on the Martian surface.

“The atmosphere provides a level of shielding, and so charged-particle radiation is less when the atmosphere is thicker,” said RAD Principal Investigator Don Hassler of the Southwest Research Institute in Boulder, Colo. See the data graphs herein.

“Absolutely, the astronauts can live in this environment. It’s not so different from what astronauts might experience on the International Space Station. The real question is if you add up the total contribution to the astronaut’s total dose on a Mars mission can you stay within your career limits as you accumulate those numbers. Over time we will get those numbers,” Hassler explained.

The initial RAD data from the first two months on the surface was revealed at a media briefing for reporters on Thursday, Nov. 15 and shows that radiation is somewhat lower on Mars surface compared to the space environment due to shielding from the thin Martian atmosphere.

Image caption: Longer-Term Radiation Variations at Gale Crater. This graphic shows the variation of radiation dose measured by the Radiation Assessment Detector on NASA’s Curiosity rover over about 50 sols, or Martian days, on Mars. (On Earth, Sol 10 was Sept. 15 and Sol 60 was Oct. 6, 2012.) The dose rate of charged particles was measured using silicon detectors and is shown in black. The total dose rate (from both charged particles and neutral particles) was measured using a plastic scintillator and is shown in red. Credit: NASA/JPL-Caltech/ SwRI

RAD hasn’t detected any large solar flares yet from the surface. “That will be very important,” said Hassler.

“If there was a massive solar flare that could have an acute effect which could cause vomiting and potentially jeopardize the mission of a spacesuited astronaut.”

“Overall, Mars’ atmosphere reduces the radiation dose compared to what we saw during the cruise to Mars by a factor of about two.”

RAD was operating and already taking radiation measurements during the spacecraft’s interplanetary cruise to compare with the new data points now being collected on the floor of Gale Crater.

Mars atmospheric pressure is a bit less than 1% of Earth’s. It varies somewhat in relation to atmospheric cycles dependent on temperature and the freeze-thaw cycle of the polar ice caps and the resulting daily thermal tides.

“We see a daily variation in the radiation dose measured on the surface which is anti-correlated with the pressure of the atmosphere. Mars atmosphere is acting as a shield for the radiation. As the atmosphere gets thicker that provides more of a shield. Therefore we see a dip in the radiation dose by about 3 to 5%, every day,” said Hassler.

Image Caption: Curiosity Self Portrait with Mount Sharp at Rocknest ripple in Gale Crater. Curiosity used the Mars Hand Lens Imager (MAHLI) camera on the robotic arm to image herself and her target destination Mount Sharp in the background. Mountains in the background to the left are the northern wall of Gale Crater. This color panoramic mosaic was assembled from raw images snapped on Sol 85 (Nov. 1, 2012). Credit: NASA/JPL-Caltech/MSSS/Ken Kremer/Marco Di Lorenzo

There are also seasonal changes in radiation levels as Mars moves through space.

The RAD team is still refining the radiation data points.

“There’s calibrations and characterizations that we’re finalizing to get those numbers precise. We’re working on that. And we’re hoping to release that at the AGU [American Geophysical Union] meeting in December.”

Image caption: Daily Cycles of Radiation and Pressure at Gale Crater. This graphic shows the daily variations in Martian radiation and atmospheric pressure as measured by NASA’s Curiosity rover. As pressure increases, the total radiation dose decreases. When the atmosphere is thicker, it provides a better barrier with more effective shielding for radiation from outside of Mars. At each of the pressure maximums, the radiation level drops between 3 to 5 percent. The radiation level goes up at the end of the graph due to a longer-term trend that scientists are still studying. Credit: NASA/JPL-Caltech/SwRI

Radiation is a life limiting factor to habitability. RAD is the first science instrument to directly measure radiation from the surface of a planet other than Earth.

“Curiosity is finding that the radiation environment on Mars is sensitive to Mars weather and climate,” Hassler concluded.

Unlike Earth, Mars lost its magnetic field some 3.5 billion years ago – and therefore most of its shielding capability from harsh levels of energetic particle radiation from space.

Much more data will need to be collected by RAD before any final conclusions on living on Mars, and for how long and in which type habitats, can be drawn.

Learn more about Curiosity and NASA missions at my upcoming free public presentations:

And be sure to watch the excellent PBS NOVA Mars documentary – ‘Ultimate Mars Challenge’ – which also features Curiosity mosaics created by the imaging team of Ken Kremer & Marco Di Lorenzo.

Ken Kremer

…..

Dec 6: Free Public lecture titled “Atlantis, The Premature End of America’s Shuttle Program and What’s Beyond for NASA” including Curiosity, Orion, SpaceX and more by Ken Kremer at Brookdale Community College/Monmouth Museum and STAR Astronomy club in Lincroft, NJ at 8 PM

Dec 11: Free Public lecture titled “Curiosity and the Search for Life on Mars (in 3 D)” and more by Ken Kremer at Princeton University and the Amateur Astronomers Association of Princeton (AAAP) in Princeton, NJ at 8 PM.

Posted on by Nancy Atkinson

Change of Command on the Space Station

Before the crew of Expedition 32/33 comes home today, astronaut and commander Suni Williams handed over the reins of the International Space Station to Kevin Ford during the traditional change of command ceremony … which was not so traditional. Williams handed out gifts to the new crew, and at times seemed quite emotional. Last week Williams wrote in her blog that she really didn’t want to think about leaving the ISS. “Up to this point I haven’t, and sort of denied it,” she wrote. “And, I am still in denial, but I am going thru the motions because I don’t want to forget something when the hatch closes.”

Williams, Aki Hoshide of the Japanese Aerospace Exploration Agency, and Russian cosmonaut Yuri Malenchenko will return home after what seems like a short 125 days in space, arriving at the ISS on July 17.

They will leave the station today (Sunday, Nov 18), undocking at 22:26 UTC (5:26 p.m. EST) Sunday and land in Kazakhstan at 01:53 UTC on Monday (8:53 p.m EST Sunday). You can watch live coverage on NASA TV.

Remaining onboard the ISS to begin Expedition 34 are Ford, Oleg Novitskiy and Evgeny Tarelkin. They will be joined by Chris Hadfield of the Canadian Space Agency, Russian cosmonaut Roman Romanenko, and NASA’s Tom Marshburn on Dec. 21 to bring the ISS crew compliment back to six. As Ford notes in the video, the new crew are “newbies” with a combined in-space experience of about 3 months, while Williams and her crew have a combined time in space of about 3 years.

JAXA astronaut Aki Hoshide during an EVA on Nov. 1, 2012, where he and Suni Williams worked to troubleshoot problems with an ammonia leak outside the ISS. Credit: NASA

The time Williams, Hoshide and Malenchenko were on board saw the October arrival the first official commercial spacecraft, SpaceX’s Dragon. Williams and Hoshide also carried out two spacewalks, with Williams now holding the record for total spacewalk time by a female at 50 hours and 40 minutes over seven career spacewalks. Malenchenko is a space veteran with several Soyuz flights, a flight on the Space Shuttle and three stints on the ISS.

Here’s the scene as Williams, Hoshide and Malenchenko say goodbye and close the hatches between the ISS and Soyuz:

Posted on by Nancy Atkinson

Watch: Ultimate Mars Challenge

The PBS special “Ultimate Mars Challenge” that aired this week in the US is now available on YouTube. The production crew did a great job capturing the challenges of putting this mission together, and included scenes from building and testing the rover here on Earth to the nail-biting landing to even including some of the most recent images and discoveries from the mission.

Note: if the video above doesn’t play in your country, try going to the PBS NOVA website and watching it there. You can read more information about the episode here. As we mentioned previously, some of the mosaics and panoramas put together by Universe Today writer Ken Kremer, along with his imaging team partner Marco Di Lorenzo, were used in the PBS show. Congrats to Ken and Marco! Below is one of their images that was used:

Curiosity looks back to her rover tracks and the foothills of Mount Sharp and the eroded rim of Gale Crater in the distant horizon on Sol 24 (Aug. 30, 2012). This panorama is featured on PBS NOVA Ultimate Mars Challenge’ documentary premiering on Nov. 14. The colorized mosaic was stitched together from Navcam images. Credit: NASA / JPL-Caltech / Ken Kremer / Marco Di Lorenzo

Posted on by Nancy Atkinson

HUGE New Gale Crater Panoramas from Curiosity

The image above is a gorgeous view of the Curiosity rover’s surroundings in Gale Crater. However, it is just a sliver of an entire gigantic panorama put together by imaging wizard Stuart Atkinson. It’s made from 34 different images as Curiosity took in a full view of its environs. You can see the full panorama at Stu’s Gale Gazette website, where you can click on it to enlarge it, and as Stu says, “then take a good long look at the beautiful hills forming the rim of the crater. Just magnificent, aren’t they?”

Sure are. Stu told me via email that all this view is missing are “some sand ships hissing over the distant plain, glinting and flashing gold, sapphire and emerald in the sunlight, and a line of sword-swinging Tharks rushing towards the rover!”

Ah, I love Stu’s Barsoomian imagination…

Another imaging wizard from UnmannedSpaceflight.com, James Canvin, is also working on a Gigapan of some of the latest images and at last count has put together 371 images into one huge panorama! The Gigapan technology allows you to pan around and zoom in to see incredible details. Check it out.

UT writer Ken Kremer is also working on some new panoramas, along with his imaging partner Marco Di Lorenzo. Congrats are in order to Ken and Marco for the images, mosaics and panoramas they put together from the MSL mission being used in the PBS NOVA special presentation that aired this week, Ultimate Mars Challenge. The show is now available to watch online: on Universe Today here, or at the PBS website here. There is additional information about the show here.