Voyager 1

NASA Scientists Find ‘Impossible’ Cloud on Titan — Again

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The hazy globe of Titan hangs in front of Saturn and its rings in this natural color view from NASA’s Cassini spacecraft. Image credit: NASA/JPL-Caltech/Space Science Institute


The puzzling appearance of an ice cloud seemingly out of thin air has prompted NASA scientists to suggest that a different process than previously thought — possibly similar to one seen over Earth’s poles — could be forming clouds on Saturn’s moon Titan.

Located in Titan’s stratosphere, the cloud is made of a compound of carbon and nitrogen known as dicyanoacetylene (C4N2), an ingredient in the chemical cocktail that colors the giant moon’s hazy, brownish-orange atmosphere. 

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Voyager 1 Helps Solve Interstellar Medium Mystery

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NASA’s Voyager 1 spacecraft made history in 2012 by entering interstellar space, leaving the planets and the solar wind behind. But observations from the pioneering probe were puzzling with regard to the magnetic field around it, as they differed from what scientists derived from observations by other spacecraft.

A new study offers fresh insights into this mystery. Writing in the Astrophysical Journal Letters, Nathan Schwadron of the University of New Hampshire, Durham, and colleagues reanalyzed magnetic field data from Voyager 1 and found that the direction of the magnetic field has been slowly turning ever since the spacecraft crossed into interstellar space. They believe this is an effect of the nearby boundary of the solar wind, a stream of charged particles that comes from the sun.

“This study provides very strong evidence that Voyager 1 is in a region where the magnetic field is being deflected by the solar wind,” said Schwadron, lead author of the study.

Researchers predict that in 10 years Voyager 1 will reach a more “pristine” region of the interstellar medium where the solar wind does not significantly influence the magnetic field.

Voyager 1’s crossing into interstellar space meant it had left the heliosphere — the bubble of solar wind surrounding our sun and the planets. Observations from Voyager’s instruments found that the particle density was 40 times greater outside this boundary than inside, confirming that it had indeed left the heliosphere.

But so far, Voyager 1’s observation of the direction of the local interstellar magnetic field is more than 40 degrees off from what other spacecraft have determined. The new study suggests this discrepancy exists because Voyager 1 is in a more distorted magnetic field just outside the heliopause, which is the boundary between the solar wind and the interstellar medium.

“If you think of the magnetic field as a rubber band stretched around a beach ball, that band is being deflected around the heliopause,” Schwadron said.

In 2009, NASA’s Interstellar Boundary Explorer (IBEX) discovered a “ribbon” of energetic neutral atoms that is thought to hold clues to the direction of the pristine interstellar magnetic field. The so-called “IBEX ribbon,” which forms a circular arc in the sky, remains mysterious, but scientists believe it is produced by a flow of neutral hydrogen atoms from the solar wind that were re-ionized in nearby interstellar space and then picked up electrons to become neutral again.

The new study uses multiple data sets to confirm that the magnetic field direction at the center of the IBEX ribbon is the same direction as the magnetic field in the pristine interstellar medium. Observations from the NASA/ESA Ulysses and SOHO spacecraft also support the new findings.

“All of these different data sets that have been collected over the last 25 years have been pointing toward the same meeting point in the field,” Schwadron said.

Over time, the study suggests, at increasing distances from the heliosphere, the magnetic field will be oriented more and more toward “true north,” as defined by the IBEX ribbon. By 2025, if the field around Voyager 1 continues to steadily turn, Voyager 1 will observe the same magnetic field direction as IBEX. That would signal Voyager 1’s arrival in a less distorted region of the interstellar medium.

“It’s an interesting way to look at the data. It gives a prediction of how long we’ll have to go before Voyager 1 is in the medium that’s no longer strongly perturbed,” said Ed Stone, Voyager project scientist, based at the California Institute of Technology in Pasadena, who was not involved in this study.

While Voyager 1 will continue delivering insights about interstellar space, its twin probe Voyager 2 is also expected to cross into the interstellar medium within the next few years. Voyager 2 will make additional observations of the magnetic field in interstellar space and help scientists refine their estimates.

Voyager 1 and Voyager 2 were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. 

Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft. Voyager 1 is the most distant object touched by human hands.
JPL, a division of Caltech, built the twin Voyager spacecraft and operates them for the Heliophysics Division within NASA’s Science Mission Directorate in Washington.
For more information about Voyager, visit:

NASA Awards Radiation Challenge Winners, Next Round Seeking Ideas for Protecting Humans on the Journey to Mars

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This illustration depicts our heliosphere, showing the approximate locations of Voyager 1 and Voyager 2 spacecraft. Galactic cosmic rays originate outside the heliosphere and stream in uniformly from all directions. Image Credit: NASA
NASA awarded $12,000 to five winners of a challenge to mitigate radiation exposure on deep space missions and launched a new follow-on challenge to identify innovative ways of protecting crews on the journey to Mars.

The follow-on challenge offers an award of up to $30,000 for design ideas to protect the crew on long-duration space missions. Anyone can participate in the challenge, which will be open Wednesday, April 29 through Monday, June 29, 2015.

“We are very impressed with the enthusiasm and sheer number of people from the public who showed interest in solving this very difficult problem for human space exploration,” said Steve Rader, deputy manager of the Center of Excellence for Collaborative Innovation. “We look forward to seeing what people will come up with in this next challenge to find the optimal configuration for these different protection approaches.”

Galactic cosmic rays (GCRs), high-energy radiation that originates outside the solar system are a major issue facing future space travelers venturing beyond low-Earth orbit. These charged particles permeate the universe and exposure to them is inevitable during space exploration. Because missions to Mars will require crews to remain beyond the protection of Earth’s magnetic field and atmosphere for approximately 500 days and potentially more than 1,000 days, learning how to protect human explorers from the effect of exposure to GCRs is a high priority.

While the five winners selected in the first challenge did not identify a solution that ultimately solves the problem of GCR risk to human crews, the first place idea did provide a novel approach to using and configuring known methods of protection to save substantial launch mass and lower launch costs over multiple missions. The other winning submissions all provided solid proposed configurations on known approaches and were supported with sound engineering and mathematics.

NASA received 136 submissions. The five selected winners are:

  • 1st place ($5,000): George Hitt, assistant professor of Physics and Nuclear Engineering at Khalifa University, United Arab Emirates, for his novel idea on reusing a shield that could be placed in a Mars Transfer Orbit.
  • 2nd Place ($3,000): Ian Gallon, retired researcher in electro-magnetics of Bridport, England, for his mathematical details on what it would take for an active radiation mitigation system to function well.
  • 3rd Place ($2,000): Olivier Loido, freelance engineer of Toulouse, France, for his concepts for a launch configuration and deploying an array of magnets.
  • 4th Place ($1,000 each): Markus Novak, recent graduate from Ohio State University of Dublin, Ohio, for his creation of safe areas through particle trajectory simulations, and Mikhail Petrichenkov of Russia for his concept of operations making use of NASA Storm Shelter work.

NASA’s goal is to identify key solutions that will reduce crew members’ total radiation dose from exposure to GCRs on long duration deep space missions by at least a factor of four.

In a continued effort to achieve that goal, the agency has developed a second challenge that asks the public for ideas on optimal configurations of active and passive solutions to provide crew members maximum protection. Active protection uses magnetic or electrostatic fields to deflect the harmful radiation, while passive protection uses material layering to shield the crew from the GCRs.

These challenges are managed by the Center of Excellence for Collaborative Innovation (CoECI). CoECI is a multi-center organization established at the request of the White House Office of Science and Technology Policy to advance NASA’s open innovation efforts and extend that expertise to other federal agencies. CoECI is directly supported by the Human Health and Performance Directorate at NASA’s Johnson Space Center in Houston. The challenges are hosted on the NASA Innovation Pavilion through its contract with InnoCentive, Inc.

To participate in the challenge beginning April 29, visit:

For additional information about the galactic cosmic ray challenges, visit: