Posted on by Nancy Atkinson

Next TEGA “Bake” Could Be Last for Phoenix

The “vibrating” done to get the first Mars arctic soil sample into Phoenix’s TEGA (Thermal and Evolved Gas Analyzer) oven may have caused a short circuit that could happen again the next time the oven is used, perhaps with fatal results. A team of engineers and scientists assembled to assess TEGA after a short circuit was discovered in the instrument, and came to a fairly disheartening conclusion. “Since there is no way to assess the probability of another short circuit occurring, we are taking the most conservative approach and treating the next sample to TEGA as possibly our last,” said Peter Smith, Phoenix’s principal investigator. Therefore, the Phoenix team is doing everything they can to assure the next sample delivered to TEGA will be ice-rich.

The short circuit was believed to have been caused when TEGA’s oven number four was vibrated repeatedly over the course of several days to break up clumpy soil so that it could get inside the oven. Delivery to any TEGA oven involves a vibration action, and turning on the vibrator in any oven will cause oven number 4 to vibrate as well, which could cause a short.

A sample taken from the trench called “Snow White” that was in Phoenix’s robotic arm’s scoop earlier this week likely has dried out, so the soil particles are to be delivered to the lander’s optical microscope on Thursday. If material remains in the scoop, the rest will be deposited in the Wet Chemistry Laboratory, possibly early on Sunday.

The mission teams will mark the Independence Day holiday with a planned “stand down” from Thursday morning, July 3, to Saturday evening, July 5. A skeleton crew at the University of Arizona in Tucson, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and Lockheed Martin Space Systems in Denver, Colo., will continue to monitor the spacecraft and its instruments over the holiday period.

“The stand down is a chance for our team to rest, but Phoenix won’t get a holiday,” Smith said. The spacecraft will be operating from pre-programmed science commands, taking atmospheric readings and panoramas and other images.

Once the sample is delivered to the chemistry experiment, Smith said the highest priority will be obtaining the ice-rich sample and delivering it to TEGA’s oven number zero.

The Phoenix team will conduct tests and trial runs so the instruments can deliver the icy sample quickly, in order to avoid sublimation of materials during the delivery process, so the solid ice doesn’t vaporize.

Original News Source: Phoenix News

Posted on by Nancy Atkinson

Where In The Universe Challenge #10

I’ve been enjoying a few lazy days of summer relaxing by a lake. The weather has been perfect, the lake is clear and warm, the food and drinks plentiful; a perfect vacation. But I finally realized (late in the day) today is Wednesday, and its time for another “Where In The Universe” challenge. So, here’s an image, and your mission is to guess where in the universe this picture was taken. You get extra points for guessing the spacecraft that is responsible for the image, too. So take your time, maybe put your feet up and grab a cold beverage on this warm day and ponder this image for awhile. No peeking below for the answer until you’ve made your guess.

When I first saw this image, I thought for sure it was a picture of some icy planetary surface or body of water. But actually, its not ice at all. This is Lake Erie, in the United States, and the image was taken on May 28th, 2006 at about noon local time, on a nice summer day. The sun is just at the right angle that causes a glint off the water, giving it an icy appearance. The image shows features on the surface of Lake Erie, about 50 kilometers (30 miles) west of Cleveland, Ohio.

The image shows V-shaped wakes of small water craft, as well as broad patterns of larger craft, probably large freighters carrying cargo, that displace and disturb more water during passage. These larger wakes are aligned with the direct course between Detroit and Cleveland (not shown in the image). Some of the broad, ill-defined swaths of light and dark (aligned from lower left to upper right) are streaks of wind-roughened water, which reflect the Sun differently.

This image was taken by an astronaut on board the International Space Station with a Kodak 760C digital camera using an 800 mm lens. They are provided by the ISS Crew Earth Observations experiment and the Image Science & Analysis Group, Johnson Space Center.

So, where ever you are, you can now enjoy gazing at a lake, just like I’ve been doing all week. My lake is a lot smaller than Lake Erie, though. But, enjoy!

Learn more about this image at NASA’s Earth Observatory site.

Posted on by Nancy Atkinson

GLAST Powers Up

The GLAST (Gamma-ray Large Area Space Telescope) spacecraft blasted off on June 11, 2008, and after acclimating to the cold reaches of space, the instruments on board are now powering up and have sent back signals to Earth indicating that all systems are operational. Meanwhile back on Earth, several bases of operations for the telescope are gearing up for processing data from the various instruments.

The Large Area Telescope (LAT), one of two instruments aboard GLAST has sent back data to Stanford Linear Accelerator Center’s Instrument Science Operations Center (ISOC) where it will be monitored, processed, and distributed to the rest of the science team worldwide. The observatory is commanded from the Mission Operations Center (MOC) at NASA Goddard Space Flight Center, and during the present initial on-orbit commissioning phase is staffed by a team from across the mission.

Manager Rob Cameron said, “Powering up the LAT has been even smoother than we had hoped. Everything has worked well-in fact, it’s going great. We’re already receiving high-quality data that we
can use to get the instrument ready for the best science return.”

Peter Michelson, of Stanford University, spokesperson and principal investigator for the LAT collaboration, said, “We’re off to a great start and we’re looking forward to a new view of our universe once science operations begin.”

GLAST will explore the most extreme, high energy environments in the universe, and seek answers to questions about dark matter, supermassive black hole systems, pulsars, and the origin of cosmic rays. It also will study the mystery of gamma-ray bursts.

VIDEO of GLAST and gamma rays from pulsars

After the 60-day checkout and initial calibration period, the project will begin science operations in earnest. The LAT will perform a full-sky survey for the first year of the mission and will rapidly respond to gamma-ray bursts detected by both GLAST instruments.

NASA’s GLAST mission has been developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

Original News Source: NASA’s GLAST Site

Posted on by Nancy Atkinson

STEREO Maps Far Reaches of Solar System

NASA’s twin STEREO spacecraft have been studying the sun since their launch in 2006. But the mission made a surprising and unexpected discovery by detecting particles from the edge of the solar system, and for the first time, scientists have now been able to map the region where the hot solar wind meets up with the cold interstellar medium. However, this wasn’t done with optical instruments imaging in visible light, but by mapping the region by means of neutral, or uncharged, atoms. This breakthrough is a “new kind of astronomy using neutral atoms,” said Robert Lin, from the University of California Berkeley, and lead for the suprathermal electron sensor aboard STEREO. “You can’t get a global picture of this region, one of the last unexplored regions of the heliosphere, any other way because it is too tenuous to be seen by normal optical telescopes.” The findings also help clear up a discrepancy in the amount of energy in the region found by the Voyager 2 spacecraft as it passed through the edge of the solar system last year.

The heliosphere stretches from the sun to more than twice the distance of Pluto. Beyond its edge, called the heliopause, lies the relative quiet of interstellar space, at about 100 astronomical units (AU) – 100 times the Earth-sun distance. The termination shock is the region of the heliosphere where the supersonic solar wind slows to subsonic speed as it merges with the interstellar medium. The heliosheath is the region of churning plasma between the shock front and the interstellar medium.

The twin STEREO spacecraft, in Earth’s orbit about the sun, take stereo pictures of the sun’s surface and measure magnetic fields and ion fluxes associated with solar explosions.

Between June and October 2007, however, the suprathermal electron sensor in the IMPACT (In-situ Measurements of Particles and CME Transients) suite of instruments on board each STEREO spacecraft detected neutral atoms originating from both the shock front and the heliosheath beyond.

“The suprathermal electron sensors were designed to detect charged electrons, which fluctuate in intensity depending on the magnetic field,” said lead author Linghua Wang, a graduate student in UC Berkeley’s Department of Physics. “We were surprised that these particle intensities didn’t depend on the magnetic field, which meant they must be neutral atoms.”

UC Berkeley physicists concluded that these energetic neutral atoms were originally ions heated up in the termination that lost their charge to cold atoms in the interstellar medium and, no longer hindered by magnetic fields, flowed back toward the sun and into the suprathermal electron sensors on STEREO.

“This is the first mapping of energetic neutral particles from beyond the heliosphere,” Lin said. “These neutral atoms tell us about the hot ions in the heliosheath. The ions heated in the termination shock exchange charge with the cold, neutral atoms in the interstellar medium to become neutral, and then flow back in.”

According to Lin, the neutral atoms are probably hydrogen, since most of the particles in the local interstellar medium are hydrogen.

The findings from STEREO, reported in the July 3 issue of the journal Nature, clear up a discrepancy in the amount of energy dumped into space by the decelerating solar wind that was discovered last year when Voyager 2 crossed the solar system’s termination shock and entered the surrounding heliosheath.

The newly discovered population of ions in the heliosheath contains about 70 percent of the energy dissipated in the termination shock, exactly the amount unaccounted for by Voyager 2’s instruments, the UC Berkeley physicists concluded. The Voyager 2 results are reported in the same issue of Nature.

A new NASA mission, the Interstellar Boundary Explorer (IBEX), is planned for launch later this year to map more thoroughly the lower-energy energetic ions in the heliosheath by means of energetic neutral atoms to discover the structure of the termination shock and how hydrogen ions are accelerated there.

Original News Source: EurekAlert

Posted on by Fraser Cain

Seasons on Saturn

Collage showing the change in seasons on Saturn. Credit: NASA/ESA/Hubble

Like Earth, Saturn’s axis is tilted relative to the Sun’s equator – 27-degrees on Saturn, compared to 23-degrees for Earth. And this tilt is very easy to see, because Saturn’s rings extend out from its equator. There are times during its orbit when we see Saturn’s rings fully extended, and other times when the rings are just a thin line, seen edge on.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

Since Saturn takes 30 years to orbit the Sun, so it’s seasons are much, much longer than Earth’s. Each of the planet’s hemispheres take turns soaking up radiation from the Sun, heating up. When the rings are fully facing the Sun, they can shade the planet, and further decrease the amount of energy received by the hemisphere experiencing winter.

And these seasons do have an impact on the planet’s weather. Over the course of 20 years, scientists recorded that wind speeds around Saturn’s equatorial regions decreased by about 40%. NASA’s Voyager flybys in 1980-81 detected wind speeds of 1,700 km/h, while they were only going about 1,000 km/h in 2003.

Here’s an article from Universe Today about how Saturn’s weather changes over long periods, and the discovery of a cyclone at the planet’s north pole.

Astronomy Picture of the Day has a beautiful image of Saturn’s changing seasons, and an article from BBC about the planet’s changing wind speeds.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.

Posted on by Fraser Cain

Temperature of Saturn

Color view of Saturn. Image credit: NASA/JPL/SSI

It’s almost impossible to say what is the temperature of Saturn. The highest cloud tops, right at the edge of space, are colder than -150 °C. But as you travel down into the planet, pressures and temperatures rise. At the very core, temperatures can reach 11,700 °C.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

As I mentioned above, the internal core of Saturn gets as high as 11,700 °C. This comes from the huge amount of hydrogen and helium compressing down and heating up the core.

Saturn actually generates heat. In fact, it’s putting out 2.5 times as much energy as it receives from the Sun. This is because the planet’s gravity is slowly compressing it down, and generating heat as it does this.

Once you reach the cloud layers in Saturn’s atmosphere, temperatures drop quickly. The bottom of the clouds are made of water ice and have an average temperature of -23 °C. Above this is a layer of ammonium hydrosulfide ice, with an average temperature of -93 °C. Above this are the ammonia ice clouds that give Saturn its orange/yellow color. Temperatures at the very edge of Saturn can get as low as -150 °C.

Here’s an article about a hot spot on Saturn, and the temperature of its rings.

Here’s an article about Saturn from How Stuff Works, and more facts on Saturn from ESA.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.

Posted on by Fraser Cain

What Color is Saturn?

Color view of Saturn. Image credit: NASA/JPL/SSI

Even through a small telescope, Saturn takes on a beautiful pale yellow with hints of orange. With a more powerful telescope, like Hubble, or images captured by NASA’s Cassini spacecraft, you can see subtle cloud layers, swirling storms mixing orange and white together.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

But what gives Saturn its color?

Like Jupiter, Saturn is made almost entirely of hydrogen, a small amount of helium, and then trace amounts of other compounds, like ammonia, water vapor and hydrocarbons.

The colors we see come just from the upper cloud layers of Saturn, which are largely composed of ammonia crystals, and the lower level clouds are either ammonium hydrosulfide or water.

Saturn has a banded pattern in its atmosphere, similar to Jupiter, but they’re much fainter and wider near the equator. It also has long-lived storms – nothing like Jupiter’s Great Red Spot – which often occur when the planet nears the summer solstice for the northern hemisphere.

Some photographs of Saturn captured by NASA’s Cassini spacecraft make the planet look blue, similar to Uranus. But this is probably just because of how the light is scattering from Cassini’s perspective.

This article has a nice full-color image of Saturn, and another nice wallpaper of Saturn.

Here’s a beautiful image of Saturn from Solar Views, and a false color image from Hubble.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.

Posted on by Nancy Atkinson

Proposed Mission Could Study Space-Time Around Black Holes

What do black holes, magnetars and supernovae have in common? They all emit X-rays. But it’s difficult, if not impossible to study certain aspects of the X-ray emissions from these powerful objects. And there’s much we don’t understand about how black holes distort space-time around them, or how magnetars affect their surroundings, or how cosmic rays are accelerated by shocks in supernova remnants. A proposed new NASA mission called Gravity and Extreme Magnetism (GEMS), will use a new technique to study what has been unattainable until now. GEMS won’t study the X-ray emission of these objects directly, but will build up a picture indirectly by measuring the polarization of X-rays emitted from these violent regions.


No current mission has resolution to do this, or in the case of magnetic field imaging, simply can’t do this because magnetic fields are invisible.

X-rays are very powerful, and like all light, X-rays have a vibrating electric field. When light travels freely through space, it can vibrate in any direction. However, under certain conditions, it becomes polarized, meaning it is forced to vibrate in only one direction. This happens when light scatters off of a surface, for example.

In a similar manner, we use polarized glasses to reduce road glare. The glare is simply light that has become polarized by scattering off the road. The glasses are made to block polarized light, so they eliminate the glare.

“GEMS will be the first mission designed just to measure the polarization of these X-rays, which will enable us to explore these exotic places in an unprecedented way,” said GEMS Principal Investigator Dr. Jean Swank of NASA’s Goddard Space Flight Center in Greenbelt, Md.
GEMS was proposed as part of NASA’s Explorer program, and was selected as one of six missions for a detailed concept study. NASA will select two of the six for development in the spring of 2009. One selected mission is scheduled to launch in 2012, and the other is planned for launch in 2015.

“GEMS will be able to tell the shapes of the X-ray-emitting matter trapped near black holes better than existing missions can — in particular, whether matter around a black hole is confined to a flat disk or puffed into a sphere or squirting out in a jet,” said Swank.

“Since X-rays are polarized by the space swirling around a spinning black hole, GEMS also provides a method of determining black hole spin independent of other techniques, which is needed to check their accuracy,” said Swank.

The heart of GEMS will be a small chamber filled with gas. As X-rays travel through the gas, they release a cloud of electrons along their path. Since the electrons tend to move in the same direction as the electric field produced by the X-ray, the instrument will measure the electron cloud to get the direction of the X-ray’s electric field, which is the same as its polarization.

Original News Source: PhysOrg

Posted on by Ian O'Neill

“Almost Perfect” Samples are Scraped From Mars Surface For Analysis

The tranch called Snow White where the scrapes of ice and soil were extracted (NASA/UA)

With the Phoenix Mars lander in full science-operation-swing, the robotic arm has just scraped an “almost perfect” mix of regolith and water ice for its next analysis. Using a blade on the scoop, the robotic arm carried out 50 scraping actions across the bottom of the enlarged “Snow White” trench that was excavated on June 17th (22 sols since Phoenix touched down). Today, on Sol 33 of the mission, Phoenix has been preparing little mounds of dirt ready to be scooped up and dropped into the Thermal and Evolved-Gas Analyzer (TEGA) so the constituent minerals and water can be analysed. Besides, Phoenix has just built the first ever mini-sand castles on the Martian surface!

On Sol 24 of the mission, only 24 sols after it landed on Mars, Phoenix found the first evidence of water ice on the Martian surface. Pictures taken four sols apart showed a white substance had sublimed into the tenuous Martian atmosphere at about the correct rate for water ice under those conditions. This was after a bumpy start when the clumpy regolith didn’t make it past the TEGA screen in a preliminary oven experiment. Then last week, Phoenix carried out a preliminary “wet-lab” test with the Microscopy, Electrochemistry and Conductivity Analyzer (MECA) instrument and found the mix of minerals in the Mars regolith and its pH levels had a striking resemblance with soils commonly found here on Earth. With all these groundbreaking discoveries mounting up, what can we expect next?

Well, today’s announcement suggests the next step is to thoroughly prepare small piles of samples scraped from the bottom of a trench called “Snow White” dug on Sol 22. Once this is complete, each sample (containing approximately two to four teaspoonfuls) can then be sprinkled into the TEGA instrument so thorough analysis can take place. The bottom of Snow White appears to be rich in water ice, so the scraping action will have created small particles of regolith and small ice crystals. Having encountered the clumpiness of regolith before, the mission scientists are keen to push ahead with some flawless experiments.

Having overviewed the small samples, agreeing that the piles were “almost perfect samples of the interface of ice and soil,” Phoenix has been sent commands to scoop up each pile of dirt and sprinkle them into the TEGA. The instrument will then bake and analyse the soil to assess its volatile ingredients, like water. The melting point of the water ice can also be assessed. Once the data has been transmitted back to Earth scientists can begin to study the constituents of the sub-surface regolith, gaining a detailed look into just how hospitable the Red Planet could be.

Keep making those little sand castles Phoenix, we’re watching you very closely…

Source: Phoenix (University of Arizona)

Posted on by Nicholos Wethington

Canada to build World’s First Asteroid-hunting Satellite

Just yesterday (June 30th) was the 100-year anniversary of the Tunguska event, when a small piece of ice or rock exploded in the air near the Podkammenaya Tungus river in Siberia, flattening trees and scaring the heck out of people in the surrounding area. Thankfully, the blast didn’t happen in a populated area and nobody was killed, but there are many more pieces of debris floating around out there in space. If we want to do something about an asteroid headed our way, or keep astronauts safe from space debris, knowing is half the battle. Thanks to a new microsatellite being built by the Canadian Space Agency, we will soon have a better map of the objects surrounding the Earth’s orbit.

The Near Earth Object Surveillance Satellite (NEOSSat) is a small satellite, about the size of a suitcase and weighing 143 pounds (65 kilograms). This puts it in a class of satellites known as “microsatellites”. Canada has already launched a successful microsatellite mission – Microvariability and Oscillation of STars (MOST) – that measured the light oscillation of stars to determine their age.

NEOSSat will monitor asteroids, comets and space junk in near-Earth orbit – within 100 – 1240 miles (160 – 2000 km) – to create a detailed survey of objects close to the Earth. It will also track other satellites, such as geosynchronous satellites, which orbit further out at 22,400 miles (~36,000 km).

NEOSSat wont’ orbit the way many satellites do – around the equator of the Earth – but will rather follow a polar orbit, circling from pole to pole every 50 minutes. This allows it to observe near the Sun where asteroids that orbit uniquely inside the Earth’s orbit are to be found. It will use a sunshade to observe with 45 degrees of the Sun. The polar orbit also gives the spacecraft the ability to use parallax to determine the distance to asteroids, comets and debris

Because of its location outside the Earth’s atmosphere, NEOSSat can also be small – it will use only a 15cm (6 inch) telescope. The small size will make the satellite easy to pack in with another, larger satellite for launch, thus reducing the cost of the mission.

Satellites are much better at making observations because they don’t have to look through the Earth’s thick atmosphere. NEOSSat will provide a huge advantage in surveying the hundreds of thousands of objects surrounding the Earth.

Dr. Alan Hildebrand the Canada Research Chair in Planetary Science in the University of Calgary’s Department of Geoscience said,”NEOSSat being on-orbit will give us terrific skies for observing 24-hours a day, guaranteed. Keeping up with the amount of data streaming back to us will be a challenge, but it will provide us with an unprecedented view of space encompassing Earth’s orbit.”

The mission is funded by as a joint project between the Canadian Space Agency and Defense Research Development Canada.

Source: EurekAlert, NEOSSat