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Space News Update — July 29, 2014 —

Contents

In the News

Story 1:

Extension Granted for NASA's Spitzer Infrared Telescope

Story 2:

Cassini Spacecraft Reveals 101 Geysers and More on Icy Saturn Moon

Story 3:

Rough Road Ahead: Rocky Mars Terrain Challenges Curiosity Rover

Departments

The Night Sky

ISS Sighting Opportunities

NASA-TV Highlights

Space Calendar

Food for Thought

Space Image of the Week

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1. Extension Granted for NASA's Spitzer Infrared Telescope

Artist's concept of the Spitzer Space Telescope. Credit: NASA/JPL-Caltech

NASA officials said this week they plan to keep funding the Spitzer observatory for two more years, reversing a preliminary decision this spring to shut down the space-based infrared telescope due to budget concerns. Launched in August 2003, the Spitzer mission is in an extended mission. A biennial senior review panel commissioned by NASA to issue funding recommendations for the space agency's long-lived astrophysics missions concluded in May that Spitzer did not warrant further funding, at least at the levels requested by scientists. But NASA left open the opportunity for Spitzer managers to submit an amended proposal offering a dialed-back mission that required less federal funding. J.D. Harrington, a NASA spokesperson, said the space agency's science directorate received a follow-up proposal from the Spitzer team and identified funding to keep the mission going. "Of course, we are relieved that NASA has found a way forward keeping Spitzer in operation," said George Helou, deputy director of the Spitzer Science Center at the California Institute of Technology. "And we are grateful to the community and to the NASA leadership for their support." "However, we do know that some reduction in workforce will be needed because we are expecting a lower budget," Helou wrote in an email to Spaceflight Now. "In fact, even the budget we had proposed would have entailed some workforce reduction as cost savings. The implications for operations are not a planned cut in the number of observing hours, but a greater likelihood that such cuts will arise because of less refined schedules, or because of slower recovery from a fault condition. Other implications are a reduced level of funding for the observers to use in analyzing and publishing their data." In a statement, NASA said Spitzer "is an important resource for on-going infrared observations for programs across the science mission directorate." The extension granted by NASA is still subject to congressional appropriations in fiscal year 2015, which begins Oct. 1, officials said.

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Harrington said NASA's astrophysics and planetary science divisions have requested observing time on Spitzer for next year, and both divisions have committed funding to support their observations. NASA directed Spitzer managers to plan for a budget comparable to the mission's fiscal year 2014 operating budget, according to Harrington. Officials said Spitzer's budget next year will likely end up below the $15.35 million figure first requested by the mission's scientists. The space agency's top astrophysics priority is the James Webb Space Telescope, a successor to the Hubble Space Telescope set for launch in 2018. NASA says its share of the ambitious once-in-a-generation space telescope will cost U.S. taxpayers $8.8 billion. Harrington said Spitzer would incorporate a guest observer program and achieve budget savings through "operational efficiencies." Spitzer is one of NASA's famed Great Observatories alongside Hubble, the Chandra X-ray Observatory and the Compton Gamma Ray Observatory, which ended its mission in 2000. Hubble and Chandra received four-year extensions after the astrophysics senior review panel ranked those missions as high-priority. Other NASA missions, such as the Kepler planet-hunting observatory, were granted two-year extensions. "We are committed to continuing to enable Great Observatory science with the Spitzer warm mission, thereby setting the scientific stage for JWST, within allocated resources," Helou wrote in an email to Spaceflight Now. Spitzer's total cost, including its development, construction, launch and operations, comes to more than $1 billion. The telescope was launched into an Earth-trailing orbit around the sun, and it is now located about 120 million miles from Earth, a distance that is gradually increasing. Spitzer will eventually be in a position where distance and interference from the sun will prevent stable communications with Earth. "We have verified that we can operate through 2018 with manageable degradation in communications," Helou wrote in an email. "We have not tried to probe further than that." Spitzer launched with a supply of super-cold liquid helium to cool its most sensitive infrared detectors, which were designed to image some of the coldest reaches of the universe. Since 2009, Spitzer has only been able to use two of its shorter wavelength imaging bands after running out of cryogenic helium. Detectors in the near-infrared bands do not need to be chilled to do their work. But officials still see high demand for Spitzer in the astronomy community. "Researchers are asking for six times more hours of observing than we have to allocate," Helou said in an interview. "That's been the case for the last two years. There are 700 papers published every year that leverage Spitzer data." One primary task for Spitzer recently has been to follow up on planet discoveries by Kepler, confirming their existence and studying their environments. "We are making great progress both in exoplanets and in the study of the very early universe ... where we're studying the galaxies formed in the first half billion years of the universe," Helou said.

Source: Spaceflight Now Return to Contents

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2. Cassini Spacecraft Reveals 101 Geysers and More on Icy Saturn Moon

This artist's rendering shows a cross-section of the ice shell immediately beneath one of Enceladus' geyser-active

fractures, illustrating the physical and thermal structure and the processes ongoing below and at the surface. Image

Credit: NASA/JPL-Caltech/Space Science Institute

Scientists using mission data from NASA’s Cassini spacecraft have identified 101 distinct geysers erupting on

Saturn’s icy moon Enceladus. Their analysis suggests it is possible for liquid water to reach from the moon’s

underground sea all the way to its surface.

These findings, and clues to what powers the geyser eruptions, are presented in two articles published in the

current online edition of the Astronomical Journal.

Over a period of almost seven years, Cassini’s cameras surveyed the south polar terrain of the small moon, a

unique geological basin renowned for its four prominent "tiger stripe” fractures and the geysers of tiny icy

particles and water vapor first sighted there nearly 10 years ago. The result of the survey is a map of 101

geysers, each erupting from one of the tiger stripe fractures, and the discovery that individual geysers are

coincident with small hot spots. These relationships pointed the way to the geysers’ origin.

After the first sighting of the geysers in 2005, scientists suspected repeated flexing of Enceladus by Saturn’s

tides as the moon orbits the planet had something to do with their behavior. One suggestion included the

back-and-forth rubbing of opposing walls of the fractures generating frictional heat that turned ice into geyser-

forming vapor and liquid.

Alternate views held that the opening and closing of the fractures allowed water vapor from below to reach

the surface. Before this new study, it was not clear which process was the dominating influence. Nor was it

certain whether excess heat emitted by Enceladus was everywhere correlated with geyser activity.

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To determine the surface locations of the geysers, researchers employed the same process of triangulation

used historically to survey geological features on Earth, such as mountains. When the researchers compared

the geysers’ locations with low-resolution maps of thermal emission, it became apparent the greatest geyser

activity coincided with the greatest thermal radiation. Comparisons between the geysers and tidal stresses

revealed similar connections. However, these correlations alone were insufficient to answer the question,

“What produces what?”

The answer to this mystery came from comparison of the survey results with high-resolution data collected in

2010 by Cassini’s heat-sensing instruments. Individual geysers were found to coincide with small-scale hot

spots, only a few dozen feet (or tens of meters) across, which were too small to be produced by frictional

heating, but the right size to be the result of condensation of vapor on the near-surface walls of the fractures.

This immediately implicated the hot spots as the signature of the geysering process.

“Once we had these results in hand we knew right away heat was not causing the geysers, but vice versa,”

said Carolyn Porco, leader of the Cassini imaging team from the Space Science Institute in Boulder, Colorado,

and lead author of the first paper. “It also told us the geysers are not a near-surface phenomenon, but have

much deeper roots.”

Thanks to recent analysis of Cassini gravity data, the researchers concluded the only plausible source of the

material forming the geysers is the sea now known to exist beneath the ice shell. They also found that narrow

pathways through the ice shell can remain open from the sea all the way to the surface, if filled with liquid

water.

In the companion paper, the authors report the brightness of the plume formed by all the geysers, as seen

with Cassini’s high resolution cameras, changes periodically as Enceladus orbits Saturn. Armed with the

conclusion the opening and closing of the fractures modulates the venting, the authors compared the

observations with the expected venting schedule due to tides.

They found the simplest model of tidal flexing provides a good match for the brightness variations Cassini

observes, but it does not predict the time when the plume begins to brighten. Some other important effect is

present and the authors considered several in the course of their work.

Source: NASA Return to Contents

This graphic shows a 3-D model of 98 geysers whose source locations and tilts were found in a Cassini imaging survey of Enceladus' south polar terrain by the method of triangulation. Image Credit: NASA/JPL-Caltech/Space Science Institute

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3. Rough Road Ahead: Rocky Mars Terrain Challenges Curiosity Rover

Engineers are faced with surprising wheel damage on the Curiosity Mars rover mission. Credit: NASAJPL-Caltech/MSSS

The Curiosity rover's wheels have taken a beating thus far on Mars, and the road ahead may be even rockier.

The 1-ton robot has just crossed out of its landing ellipse — the 12- by 4-mile (19 by 7 kilometers) zone that was targeted for its dramatic August 2012 touchdown — and is now moving toward an increasingly challenging landscape called the Zabriskie Plateau, mission team members said.

"We are heading out into very rough terrain," Curiosity project scientist John Grotzinger, a geologist at the California Institute of Technology in Pasadena, said during a presentation at the 8th International Conference on Mars, which took place at Caltech last week. "These rocks have been a problem for us."

Curiosity embarked last July on a roughly 5-mile (8 km) drive to the base of Mount Sharp, which has long been its ultimate science destination. The car-size rover has about 2 miles (3.2 km) left to go, researchers said.

Toward the end of 2013, Curiosity encountered a region studded with sharp rocks, which presented the mission with a major technical challenge. Unlike what had been experienced by other Mars rovers, these rocks were embedded in the surface like spikes in a parking lot exit. In previous encounters with such obstacles, most rolled over and did not present a risk to the rover wheels.

The sharp rocks, looking like 3- and 4-inch (7.6 and 10.2 centimeters) shark’s teeth, appeared to be wind-sculpted. Soft formations apparently overlie harder rock, and as the wind scours the region, what is left behind are the jagged remains of the tough subsurface stuff.

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"The wind becomes a big problem for our wheels," Grotzinger said. "As the rocks fall apart, they are sculpted by the wind to points that we see as we drive along."

Grotzinger and Curiosity rover planner team lead Chris Roumeliotis displayed to the audience at Caltech graphic images of wheel wear captured by Curiosity’s cameras.

"We did an inventory of the wheels," Grotzinger said, "and here’s the image that set us on into a constructed panic."

The mosaic showed wheels that had been dented, punctured and even torn by the rocks below. "To figure out what to do… you take a picture of a metal wheel," he added, "and when you see the planet on the other side [i.e. through a large hole in the wheel], unless it says 'JPL,' it's a problem."

The JPL phrase refers to the holes that had been engineered into the wheels to mark the rover’s path in the sandy surface; these holes spell out 'JPL' in Morse code. But the Martian landscape could be clearly seen through additional rips and tears in the metal.

An extensive testing campaign was immediately initiated both at JPL’s "Mars Yard," a rocky surface set up at the lab, as well as in the field near California's Death Valley. Roumeliotis showed a video of one such test. It used a roughly 3-inch by 1-inch (7.6 by 2.5 cm) aluminum spike with a dull point to simulate a sharp rock.

"Welcome to 'The Impaler,'" Roumeliotis said as the rover drove over the spike and the wheel’s surface tore like wet paper. There was a visceral gasp from the audience.

Roumeliotis pointed out that such damage only occurred when the rover was driving forward, due to the pivot points of the suspension system. A similar video of the rover driving backward showed the wheels traversing the spike with no ill effects. In the months ahead, the rover will therefore be driving backward across some of the worst areas, as it did when crossing the last rocky patch. This results in less damage, and what does occur tends to affect two wheels and not four when driving in this mode, team members said.

In a later conversation, Grotzinger pointed out that the real strength in Curiosity’s beer-keg-size wheels lies not in the tread surface but rather in the metal ridge and flexible spokes inside. "The internal rim and the flexible spokes really absorb much of the punishment," he said.

The rover team considered seven different pathways for the remaining distance between Curiosity’s current location and the 3.4-mile-high (5.5 km) Mount Sharp, whose many rock layers record a history of Mars' changing environmental conditions over time.

Curiosity will descend into a shallow, sandy-floored valley to avoid the worst of the upcoming terrain. The rover team plans to skirt the deeper sand by hugging the edge of the valley floor, where the drift thins out near the wall.

Someone posted Robert Frost’s poem "The Road Less Taken" at JPL in tribute to the challenging choices ahead, Grotzinger told the crowd. The choice seemed fitting.

"But I’ll bet Frost never imagined there could be seven routes that you might take, "Grotzinger added with a smile.

Source: Space.com Return to Contents

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The Night Sky

Source: Sky and Telescope Return to Contents

Tuesday, July 29

Vega is the brightest star very high in the east. Far down to its lower right shines Altair, almost as bright. Altair is flagged by little Tarazed (3rd magnitude) a finger-width above it, an orange giant far in Altair's background.

Wednesday, July 30

The two brightest stars of summer are Vega, just east of the zenith after dark, and Arcturus, less high toward the west. Both are zero magnitude.

The next zero-magnitude star to make its appearance will be Capella. It doesn't emerge until the early-morning hours. Look for it low in the north-northeast after about 1 a.m. local time (depending on your location, especially your latitude).

Thursday, July 31

In a really dark sky, the Milky Way now forms a magnificent arch high across the whole eastern sky after darkness is complete. It runs all the way from below Cassiopeia in the north-northeast, up and across Cygnus and the Summer Triangle high in the east, and down past the spout of the Sagittarius Teapot in the south.

Friday, August 1

At dusk this evening, the Moon forms the lower-right end of a very long, curving line of celestial objects. Counting to the Moon's upper left, these are Spica, Mars, and Saturn, as shown here.

Today is Lammas Day or Lughnasadh, one of the four traditional "cross-quarter" days midway between the solstices and equinoxes. More or less. The actual midpoint between the June solstice and the September equinox this year comes at 2:40 a.m. August 7th Eastern Daylight Time (6:40 UT). That will be the exact midpoint of astronomical summer.

Watch from night to night as the waxing Moon moves eastward past the lineup of Spica, Mars, and then Saturn. (The blue 10° scale is about the size of your fist held at arm's length. The Moon is plotted for the middle of North America, and it's shown three times actual apparent size.)

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ISS Sighting Opportunities (from Denver)

Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Time Zone)

Tuesday, July 29

8:15 a.m. - ISS Expedition 40 In-Flight Event with Flight Engineer Alexander Gerst for ESA and the German ARD Network (all channels)

8:45 a.m. - ISS Expedition 40 In-Flight Event with Flight Engineer Alexander Gerst for ESA and the German ARD Network (will be interpreted) (all channels)

7:15 p.m. - Coverage of the Launch of the European Space Agency’s “Georges Lemaitre” Automated Transfer Vehicle to the ISS (all channels)

Thursday, July 31

12 p.m. - Mars Announcement (all channels)

1:10 p.m. - ISS Expedition 40 In-Flight Event with ABC “Nightline” (all channels)

Watch NASA TV online by going to the NASA website. Return to Contents

Date Visible Max Height Appears Disappears

Tue Jul 29, 4:57 AM 2 min 19° 10 above NNW 19 above NNE

Wed Jul 30, 2:32 AM 1 min 11° 10 above NNW 11 above N

Wed Jul 30, 4:09 AM 2 min 15° 11 above NNW 15 above NNE

Thu Jul 31, 3:20 AM 1 min 12° 10 above NNW 12 above N

Thu Jul 31, 4:56 AM 6 min 37° 10 above NW 11 above E

Fri Aug 1, 2:32 AM < 1 min 11° 10 above NNW 11 above N

Fri Aug 1, 4:08 AM 5 min 25° 11 above NNW 10 above E

Fri Aug 1, 10:26 PM < 1 min 10° 10 above SW 10 above SW

Sat Aug 2, 3:19 AM 5 min 19° 10 above NNW 10 above ENE

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Space Calendar

Jul 29 - ATV-5 (Georges Lemaitre) Ariane 5 Launch (International Space Station)

Jul 29 - South Delta-Aquarids Meteor Shower Peak

Jul 29 - Comet C/2014 N2 (PANSTARRS) Closest Approach To Earth (1.431 AU)

Jul 29 - Comet 2P/Encke Closest Approach To Earth (2.130 AU)

Jul 29 - Comet 282P/2003 BM80 Closest Approach To Earth (3.017 AU)

Jul 29 - Comet C/2013 H1 (La Sagra) At Opposition (4.040 AU)

Jul 29 - Asteroid 19578 Kirkdouglas Closest Approach To Earth (1.069 AU)

Jul 29 - Asteroid 9674 Slovenija Closest Approach To Earth (1.829 AU)

Jul 29 - 15th Anniversary (1999), Deep Space 1, Asteroid Braille Flyby

Jul 30 - Comet 117P/Helin-Roman-Alu At Opposition (2.117 AU)

Jul 30 - Asteroid 103 Hera Occults HIP 91781 (6.1 Magnitude Star)

Jul 30 - Asteroid 11926 Orinoco Closest Approach To Earth (1.327 AU)

Jul 30 - Asteroid 3665 Fitzgerald Closest Approach To Earth (1.387 AU)

Jul 30 - Asteroid 2135 Aristaeus Closest Approach To Earth (1.503 AU)

Jul 31 - GPS 2F-7 Atlas 5 Launch

Jul 31 - Comet P/2013 G1 (Kowalski) Closest Approach To Earth (2.693 AU)

Jul 31 - Asteroid 2014 MD6 Near-Earth Flyby (0.075 AU)

Jul 31 - Asteroid 3904 Honda Closest Approach To Earth (1.697 AU)

Jul 31 - Asteroid 79896 Billhaley Closest Approach To Earth (1.980 AU)

Jul 31 - 15th Anniversary (1999), Lunar Prospector, Moon Impact

Jul 31 - 45th Anniversary (1969), Mariner 6, Mars Flyby

Aug 01 - Alpha Capricornids Meteor Shower Peak

Aug 01 - Comet P/1999 XN120 (Catalina) At Opposition (3.740 AU)

Aug 01 - Comet 144P/Kushida At Opposition (4.325 AU)

Aug 01 - Asteroid 2014 OG1 Near-Earth Flyby (0.068 AU)

Aug 01 - Asteroid 3949 Mach Closest Approach To Earth (1.225 AU)

Aug 01 - Asteroid 7462 Grenoble Closest Approach To Earth (1.457 AU)

Aug 01 - Asteroid 9357 Venezuela Closest Approach To Earth (1.837 AU)

Aug 01 - Asteroid 3352 McAuliffe Closest Approach To Earth (2.199 AU)

Aug 02 - Mercury Passes 1.0 Degrees From Jupiter

Source: JPL Space Calendar Return to Contents

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Food for Thought

The Most Precise Measurement of an Alien World's Size

Using data from NASA's Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement ever

of the size of a world outside our solar system, as illustrated in this artist's conception. Image Credit: NASA/JPL-Caltech

Thanks to NASA's Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement

ever of the radius of a planet outside our solar system. The size of the exoplanet, dubbed Kepler-93b, is now

known to an uncertainty of just 74 miles (119 kilometers) on either side of the planetary body.

The findings confirm Kepler-93b as a "super-Earth" that is about one-and-a-half times the size of our planet.

Although super-Earths are common in the galaxy, none exist in our solar system. Exoplanets like Kepler-93b

are therefore our only laboratories to study this major class of planet.

With good limits on the sizes and masses of super-Earths, scientists can finally start to theorize about what

makes up these weird worlds. Previous measurements, by the Keck Observatory in Hawaii, had put Kepler-

93b's mass at about 3.8 times that of Earth. The density of Kepler-93b, derived from its mass and newly

obtained radius, indicates the planet is in fact very likely made of iron and rock, like Earth.

"With Kepler and Spitzer, we've captured the most precise measurement to date of an alien planet's size,

which is critical for understanding these far-off worlds," said Sarah Ballard, a NASA Carl Sagan Fellow at the

University of Washington in Seattle and lead author of a paper on the findings published in the Astrophysical

Journal.

"The measurement is so precise that it's literally like being able to measure the height of a six-foot tall person

to within three quarters of an inch -- if that person were standing on Jupiter," said Ballard.

Kepler-93b orbits a star located about 300 light-years away, with approximately 90 percent of the sun's mass

and radius. The exoplanet's orbital distance -- only about one-sixth that of Mercury's from the sun -- implies a

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scorching surface temperature around 1,400 degrees Fahrenheit (760 degrees Celsius). Despite its newfound

similarities in composition to Earth, Kepler-93b is far too hot for life.

To make the key measurement about this toasty exoplanet's radius, the Kepler and Spitzer telescopes each watched

Kepler-93b cross, or transit, the face of its star, eclipsing a tiny portion of starlight. Kepler's unflinching gaze also

simultaneously tracked the dimming of the star caused by seismic waves moving within its interior. These readings

encode precise information about the star's interior. The team leveraged them to narrowly gauge the star's radius,

which is crucial for measuring the planetary radius.

Spitzer, meanwhile, confirmed that the exoplanet's transit looked the same in infrared light as in Kepler's visible-

light observations. These corroborating data from Spitzer -- some of which were gathered in a new, precision

observing mode -- ruled out the possibility that Kepler's detection of the exoplanet was bogus, or a so-called false

positive.

Taken together, the data boast an error bar of just one percent of the radius of Kepler-93b. The measurements

mean that the planet, estimated at about 11,700 miles (18,800 kilometers) in diameter, could be bigger or smaller

by about 150 miles (240 kilometers), the approximate distance between Washington, D.C., and Philadelphia.

Spitzer racked up a total of seven transits of Kepler-93b between 2010 and 2011. Three of the transits were

snapped using a "peak-up" observational technique. In 2011, Spitzer engineers repurposed the spacecraft's peak-up

camera, originally used to point the telescope precisely, to control where light lands on individual pixels within

Spitzer's infrared camera.

The upshot of this re-jiggering: Ballard and her colleagues were able to cut in half the range of uncertainty of the

Spitzer measurements of the exoplanet radius, improving the agreement between the Spitzer and Kepler

measurements. "Ballard and her team have made a major scientific advance while demonstrating the power of

Spitzer's new approach to exoplanet observations," said Michael Werner, project scientist for the Spitzer Space

Telescope at NASA's Jet Propulsion Laboratory, Pasadena, California.

Source: NASA Return to Contents

_________________________________________________________________________________________

NASA’s Long-Lived Mars Opportunity Rover Sets Off-World Driving Record

NASA's Opportunity Mars rover, which landed

on the Red Planet in 2004, now holds the off-Earth roving distance record after accruing 25

miles (40 km) of driving. The previous record was held by the Soviet Union's Lunokhod 2

rover. A drive of 157 feet (48 m) on July 27

put Opportunity's total odometry at 25.01 miles (40.25 km).

This month's driving brought the rover

southward along the western rim of

Endeavour Crater. The rover had driven more than 20 miles (32 km) before arriving at

Endeavour Crater in 2011. Source: NASA

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Space Image of the Week

SN 1006 Supernova Remnant

Image Credit: NASA, ESA, Zolt Levay (STScI)

Explanation: A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in

the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation

of Lupus, still puts on a cosmic light show across the electromagnetic spectrum. In fact, this composite view

includes X-ray data in blue from the Chandra Observatory, optical data in yellowish hues, and radio image data

in red. Now known as the SN 1006 supernova remnant, the debris cloud appears to be about 60 light-years

across and is understood to represent the remains of a white dwarf star.

Part of a binary star system, the compact white dwarf gradually captured material from its companion star.

The buildup in mass finally triggered a thermonuclear explosion that destroyed the dwarf star. Because the

distance to the supernova remnant is about 7,000 light-years, that explosion actually happened 7,000 years

before the light reached Earth in 1006. Shockwaves in the remnant accelerate particles to extreme energies

and are thought to be a source of the mysterious cosmic rays.

.

Source: NASA Return to Contents