Heliophysics Nugget: Mapping Tons of Meteoric Dust in the Sky

Heliophysics nuggets are a collection of early science results, new research techniques, and instrument updates that further our attempt to understand the sun and the dynamic space weather system that surrounds Earth. On Aug.11 and 12, 2013, the annual Perseid meteor shower will peak, filling the sky with streaks of light, commonly known as shooting stars. Such visually stunning showers are actually but the tip of the iceberg when it comes to meteoroids slamming into Earth's atmosphere: Some 10 to 40 tons of material of invisible meteoric dust enters the atmosphere from interplanetary space every day.

The big showers like the Perseids, and later the Leonids in November, are caused when Earth and its atmosphere travels through a region of the sky filled with left over debris lost by a particular comet. In the case of the Perseids, the small fragments were ripped of the tail of comet Swift-Tuttle, which orbits the sun once every 130 years. The fragments light up due to the immense friction created when they plough into the gas surrounding Earth. Each such fragment is approximately the size of a dime, but the more constant, sporadic meteoroids have been around much longer, breaking down over time into tiny fragments only about as wide as a piece of human hair.

"This is interplanetary dust," said Diego Janches, who studies micrometeoroids at NASA's Goddard Space Flight Center in Greenbelt, Md. "The fragments are either remnants from the solar system's formation, or they are produced by collisions between asteroids or comets from long ago". Janches researches such tiny meteoroids using radar systems set up around the globe, in places such as Sweden, Puerto Rico and Alaska, or the radar system he deployed and operates in Tierra Del Fuego, Argentina. These fragments plough into Earth's atmosphere at speeds of between 7 to 44 miles per second. They also bring with them minerals and metals from their parent bodies, such as sodium, silicon, calcium and magnesium.

"The small meteoroids feed the atmosphere with all these extra materials," Janches said. "They come in, release metallic atoms that get deposited in the mesosphere and then get pushed around from pole to pole by the general global circulation. So by using the metals as tracers, you can answer some important questions about the general composition and movement of the atmosphere." The radar systems set up around the world can track such motion. The meteors collide with atoms in the atmosphere and leave behind a path of electrons and charged particles. This electrically charged region acts as a perfect mirror for radar waves, so the radar bounces back carrying both position information and Doppler shift information. This can be used to measure speed and direction of the background atmospheric winds at the altitudes where the meteoric tails are produced, between 40 and 60 miles high in the sky. Because there are so many such trails, they can be used to measure the velocity and direction of the winds continuously, helping to map out very complex wind patterns on a minute-by-minute basis.

Similar techniques, but using lasers, can be used to map how something like sodium sweeps through the entire atmosphere, thus tracing the global circulation system. This system also sweeps the meteoric dust to the poles where, during the summertime, they can serve as nuclei for ice crystals in the sky forming what's called night-shining or noctilucent clouds.

Source: http://www.nasa.gov

Curiosity Makes Its Longest One-Day Drive on Mars

PASADENA, Calif. – NASA's Mars rover Curiosity drove twice as far on July 21 as on any other day of the mission so far: 109.7 yards (100.3 meters). The length of the drive took advantage of starting the 340th Martian day, or sol, of the mission from a location with an unusually good view for rover engineers to plan a safe path. In weeks to come, the rover team plans to begin using "autonav" capability for the rover to autonomously navigate a path for itself, which could make such long drives more frequent.

Curiosity is about three weeks into a multi-month trek, from the "Glenelg" area where it worked for the first half of 2013, to an entry point for the mission's major destination: the lower layers of Mount Sharp. The mission's longest one-day drive prior to July 21 was about 54 yards (49 meters), on Sol 50 (Sept. 26, 2012). After completing the longer drive, Curiosity drove 68.2 yards (62.4 meters) on July 23 (Sol 342), bringing the mission's total driving distance so far to 0.81 mile (1.23 kilometers).

The Sol 340 drive included three segments, with turns at the end of the first and second segments. Rover planners used information from stereo imaging by the Navigation Camera (Navcam) on Curiosity's mast, plus images from the telephoto-lens Mast Camera (Mastcam).  The drive also used the rover's capability to use imagery taken during the drive to calculate the driving distance, a way to verify that wheels have not been slipping too much while turning.

"What enabled us to drive so far on Sol 340 was starting at a high point and also having Mastcam images giving us the size of rocks so we could be sure they were not hazards," said rover planner Paolo Bellutta of NASA's Jet Propulsion Laboratory, Pasadena, Calif. “We could see for quite a distance, but there was an area straight ahead that was not clearly visible, so we had to find a path around that area."

The rover was facing southwest when the sol began. It turned slightly more to the west before driving and used visual odometry to be sure it drove the intended distance (about 55 yards or 50 meters) before turning back farther southward. The second leg, next turn, and third leg completed the drive without visual odometry, though the rover was using another new capability: to turn on visual odometry autonomously if tilt or other factors exceed predetermined limits. New software on Curiosity gives it the capability to use visual odometry through a range of temperatures. This was needed because testing this spring indicated the Navcam pair linked to the rover's B-side computer is more sensitive to temperature than anticipated. Without the compensating software, the onboard analysis of stereo images could indicate different distances to the same point, depending on the temperature at which the images are taken. The rover was switched from its A-side computer to the redundant B-side computer on Feb. 28 due to a flash-memory problem -- subsequently resolved -- on the A-side. The Navcam pair linked to the A-side computer shows less variability with temperature than the pair now in use.

"For now, we're using visual odometry mostly for slip-checking," said JPL's Jennifer Trosper, deputy project manager for Curiosity. "We are validating the capability to begin using autonav at different temperatures." The autonomous navigation capability will enable rover planners to command drives that go beyond the route that they can confirm as safe from previous-sol images. They can tell the rover to use the autonomous capability to choose a safe path for itself beyond that distance.

Curiosity landed at the "Bradbury Landing" location within Gale Crater on Aug. 6, 2012, EDT and Universal Time (Aug. 5, PDT). From there, the rover drove eastward to the Glenelg area, where it accomplished the mission's major science objective of finding evidence for an ancient wet environment that had conditions favorable for microbial life. The rover's route is now southwestward. At Mount Sharp, in the middle of Gale Crater, scientists anticipate finding evidence about how the ancient Martian environment changed and evolved.

JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover. More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .

Source: http://www.nasa.gov

Telescope Door on IRIS Solar Observatory Opens

Today at 11:14 pm PDT (2:14 pm EDT) the IRIS Lockheed Martin instrument team successfully opened the door on NASA’s Interface Region Imaging Spectrograph, which launched June 27, 2013, aboard a Pegasus XL rocket from Vandenberg Air Force Base, Calif. A 60-day check out period began at launch. The first 30 days, which ends July 27, consists of tests and spacecraft system checks. The team will use the remaining 30 days for initial observing runs to fine tune instrument observations. If all is nominal, the team plans to begin normal science mode by August 26.

All data will be available to scientists and the public as soon as the mission begins science operations. The team is looking forward to receiving high-resolution images and spectra soon after first light. Additional mission updates will be provided as warranted.

Large Coronal Hole Near the Sun’s North Pole

The European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, captured this image of a gigantic coronal hole hovering over the sun’s north pole on July 18, 2013, at 9:06 a.m. EDT. Coronal holes are dark, low density regions of the sun’s outermost atmosphere, the corona. They contain little solar material, have lower temperatures, and therefore, appear much darker than their surroundings.

Coronal holes are a typical feature on the sun, though they appear at different places and with more frequency at different times of the sun’s activity cycle. The activity cycle is currently ramping up toward what is known as solar maximum, currently predicted for late 2013. During this portion of the cycle, the number of coronal holes decreases. During solar max, the magnetic fields on the sun reverse and new coronal holes appear near the poles with the opposite magnetic alignment. The coronal holes then increase in size and number, extending further from the poles as the sun moves toward solar minimum again.  At such times, coronal holes have appeared that are even larger than this one.

The holes are important to our understanding of space weather, as they are the source of a high-speed wind of solar particles that streams off the sun some three times faster than the slower wind elsewhere. While it’s unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, failing to loop back down to the surface, as they do elsewhere.

Source: http://www.nasa.gov

Comet Ison Brings Holiday Fireworks

This July Fourth the solar system is showing off some fireworks of its own. Superficially resembling a skyrocket, comet ISON is hurtling toward the sun presently at a whopping 48,000 mph. Its swift motion is captured in this time-lapse movie made from a sequence of pictures taken May 8, 2013, by NASA’s Hubble Space Telescope. At the time the images were taken, the comet was 403 million miles from Earth, between the orbits of Mars and Jupiter.

The movie shows a sequence of Hubble observations taken over a 43-minute span and compresses this into just five seconds. The comet travels 34,000 miles in this brief video, or 7 percent of the distance between Earth and the moon. The deep-space visitor streaks silently against the background stars. Unlike a firework, the comet is not combusting, but in fact is pretty cold. Its skyrocket-looking tail is really a streamer of gas and dust bleeding off the icy nucleus, which is surrounded by a bright star-like-looking coma. The pressure of the solar wind sweeps the material into a tail, like a breeze blowing a windsock.

As the comet warms as it moves closer to the sun, its rate of sublimation (a process similar to evaporation in which solid matter transitions directly into gas) will increase. The comet will get brighter and its tail will grow longer. The comet is predicted to reach naked-eye visibility in November. The comet is named after the organization that discovered it, the Russia-based International Scientific Optical Network. This false-color, visible-light image was taken with Hubble’s Wide Field Camera 3.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy Inc., in Washington, D.C.

Source: http://www.nasa.gov

Mars rover Opportunity examining rock changed by water

The mission's engineers at NASA's Jet Propulsion Laboratory, Pasadena, California, had set this week as a deadline for starting a drive toward "Solander Point," where the team plans to keep Opportunity working during its next Martian winter. "What's so special about Esperance is that there was enough water not only for reactions that produced clay minerals, but also enough to flush out ions set loose by those reactions, so that Opportunity can clearly see the alteration," Scott McLennan of the State University of New York, Stony Brook, a long-term planner for Opportunity's science team, said.

This rock's composition is unlike any other Opportunity has investigated during nine years on Mars-higher in aluminum and silica, lower in calcium and iron. The next destination, Solander Point, and the area Opportunity is leaving, Cape York, both are segments of the rim of Endeavor Crater, which spans 14 miles (22 kilometers) across. The planned driving route to Solander Point is about 1.4 miles (2.2 kilometers). The team identified Esperance while exploring a portion of Cape York where the Compact Reconnaissance Spectrometer for Mars (CRISM) on NASA's Mars Reconnaissance Orbiter had detected a clay mineral. (ANI)

Antares rocket makes its maiden voyage into space

Orbital Sciences' Antares rocket had its first successful launch today, carrying a mock cargo ship into orbit before the rocket burned up in the atmosphere. It comes after two delays, for both weather and mechanical failure, but resulted in a strong showing for the Antares' two-stage booster engine, which utilizes a combination of liquid and solid fuels. Once testing is complete, the rocket is expected to take over resupply and crew launches to the International Space Station. The dummy cargo ship, which weighed over four tons, included three small Phonesat satellites as part of a NASA research experiment, as well as a larger Dove-1 satellite carried on behalf of telecom company Cosmogia.

It's part of a longterm shift at NASA from public missions to private contracts, which has also seen billion-dollar contracts for Elon Musk's SpaceX project project and a gradual phase-out of NASA's own space shuttle project. As one Nasa administrator told Space.com, "This is the culmination of a plan that we've been on for several years." With this successful launch behind them, Orbital Sciences is planning subsequent launches every three to six months, with two more scheduled for 2013 and at least one more mock-launch before they start ferrying actual cargo.

Russia’s Progress Cargo Spacecraft to Be ‘Buried’ in Pacific

MOSCOW, April 21 (RIA Novosti) - The Progress M-17M cargo spacecraft, which undocked from the International Space Station on April 15, will be "buried" in the Pacific Ocean on Sunday, Russia's Mission Control said. “Progress’s engines will switch to the braking mode at 6:07 p.m. Moscow time [02:07 p.m. GMT] on April 21. The space freighter’s fragments that will not burn up in the Earth’s atmosphere will splash down at 6:58 p.m. Moscow time in the Pacific Ocean far from navigation routes,” Mission Control said.

The Progress M-17M arrived at the orbital station on October 31 last year. It was the second spacecraft in the history of the world orbiter’s operation that performed an accelerated docking with the ISS just under six hours after liftoff from the Baikonur Space Center in Kazakhstan. The first accelerated docking was performed by the M-16M space freighter in August 2012. The Progress M-17M space freighter undocked from the Zvezda module of the Russian segment on the ISS on April 15 and operated in an autonomous mode in the next six days, conducting a series of scientific experiments under the Radar-Progress project.

The departure of Progress M-17M clears a docking port on the Zvezda module for the next Russian resupply vehicle, Progress M-19M, which will blast off aboard a Soyuz-U carrier rocket from the Baikonur space center on April 24. With a record of more than 130 launches since 1972, Progress-family freighters remain the backbone of the Russian space cargo fleet. In addition to their main mission as cargo spacecraft, they are used to adjust the space station’s orbit and conduct scientific experiments.

U.S. Orbital to launch space rocket Sunday

WASHINGTON, April 20 (Xinhua) -- Orbital Sciences Corp., one of two private companies that currently hold a contract with U.S. space agency NASA to fly unmanned cargo missions to the International Space Station, has rescheduled the test flight of its Antares rocket to Sunday.

"Today's Antares launch has been scrubbed due to upper wind conditions," said NASA via its official Twitter ajgn%3Dc6e next launch attempt will be Sunday, April 21 at 5 p.m. EDT ( 2100 GMT)." A Wednesday attempt to launch the rocket from NASA's Wallops Flight Facility on Wallops Island, Virginia, was called off due to "a premature separation of an umbilical connection on the second stage". The Virginia-based Orbital signed a 1.9-billion-U.S.-dollar deal with NASA to fly eight unmanned supply missions using the Antares and Cygnus cargo delivery system.

Another U.S. company, California-based SpaceX, made history when its Dragon spacecraft became the first commercial vehicle in history to successfully attach to the space station in a May 2012 test flight. Dragon has already made three trips to the space station and it still needs to complete another ten to fulfill its 1.6-billion- dollar contract with NASA. The next SpaceX cargo run is scheduled for September.

NASA sees distant planets that seem ideal for life

AP Science Writer= WASHINGTON (AP) — NASA's planet-hunting telescope has discovered two planets that seem like ideal places for some sort of life to flourish. And they are just the right size and in just the right place. One is toasty, the other nippy.

The distant duo are the best candidates for habitable planets that astronomers have found so far, said William Borucki, the chief scientist for NASA's Kepler telescope. And it's got astronomers thinking that similar planets that are just about right for life — "Goldilocks planets" — might be common in the universe. The discoveries, published online Thursday in the journal Science, mark a milestone in the search for planets where life could exist. In the four years that Kepler has been trailing Earth's orbit, the telescope has found 122 exoplanets — planets outside our solar system. In the past, those planets haven't fit all the criteria that would make them right for life of any kind from microbes to man. Many planets aren't in the habitable zone — where it's not too hot and not too cold for liquid water. And until now, the few found in that ideal zone, were just too big. Those are likely to be gas balls like Neptune and that's not suitable for life. Similarly, any Earth-size planets weren't in the right place near their stars, Borucki said. In the Goldilocks game of looking for other planets like ours, the new discoveries, called Kepler-62-e and Kepler-62-f are just right. And they are fraternal twins. They circle the same star, an orange dwarf, and are next to each other — closer together than Earth and its neighbor Mars.

The planets are slightly wider than Earth, but not too big. Kepler-62-e is a bit balmy, like a Hawaiian world and Kepler-62-f is a bit frosty, more Alaskan, Borucki said. The pair is 1,200 light-years away; a light-year is almost 6 trillion miles. "This is the first one where I'm thinking 'Huh, Kepler-62-f really might have life on it'," said study co-author David Charbonneau of Harvard. "This is a very important barrier that's been crossed. Why wouldn't it have life?"

To make it warm enough for life the planet would need greenhouse gas trapping its star's heat because the star only gives off one-fifth the energy of our sun, but that's something that is likely to happen, Borucki said. Both planets are tantalizing. The dozens of researchers who co-authored the study disagree on which one is better suited to life. Lisa Kaltenegger of the Max Planck Institute of Astronomy in Germany likes Kepler-62-e more because it's closer to the star and is warmer. She said it is probably "like Washington in May." That planet is so close it may need clouds to cool off and it's more likely to be an all-water world, unlike any other in our solar system, Kaltenegger said. Astronomers cannot confirm that either planet has water, but based on other research, it's a good assumption, she said. The planets circle a star that is 7 billion years old — about 2.5 billion years older than our sun. Kepler spots the planets as they go between Earth and their star ever so slightly, reducing the light from the star.

"If there's life at all on those planets, it must be very advanced" evolutionarily because the planets are so old, said Borucki. On a watery planet, oceans are prime spots for life, including flying fish that could evolve into birds, Borucki said. And on the rocky planet, with a heavier gravity than Earth, life might look a tad different, he said. In another study also published by some of the same authors in Astrophysical Journal, the astronomers found a different set of planets that are slightly bigger, but probably not gas giants, and circle a star that more resembles our sun. One of those planets is on edge of the habitable zone — maybe in, maybe out — and could be considered a potential third good place for a habitable zone, said Thomas Barclay of NASA's Ames Research Center, which runs the Kepler telescope.

All told, researchers announced seven new exoplanets on Thursday, upping the grand total found so far by Kepler and Earth-bound telescopes to about 850, according to NASA. Pennsylvania State University professor James Kasting called the findings "a big discovery." Kasting and Sara Seager of MIT, who weren't part of the research, pointed out that Kepler's job is to look at one distant corner of the sky and to find what fraction of stars seemed to have the right sized planets in the habitable zone. "This is HUGE," Seager wrote in an email. "Do you realize that as soon as Kepler could find close-to-Earth-size planets in the habitable zone of sun-like stars, Kepler found it. Goldilocks planets must be everywhere."

---

Online:

Science: http://www.sciencemag.org