Tag Archives: solar system

Time to Wake Up: Artist’s impression of NASA’s New Horizons spacecraft, currently en route to Pluto. Operators at the Johns Hopkins University Applied Physics Laboratory are preparing to “wake” the spacecraft from electronic hibernation on Dec. 6, when the probe will be more than 2.9 billion miles from Earth. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

New Horizons Set to Wake Up for Pluto Encounter

NASA’s New Horizons spacecraft comes out of hibernation for the last time on Dec. 6. Between now and then, while the Pluto-bound probe enjoys three more weeks of electronic slumber, work on Earth is well under way to prepare the spacecraft for a six-month encounter with the dwarf planet that begins in January.

“New Horizons is healthy and cruising quietly through deep space – nearly three billion miles from home – but its rest is nearly over,” says Alice Bowman, New Horizons mission operations manager at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. “It’s time for New Horizons to wake up, get to work, and start making history.”

Since launching in January 2006, New Horizons has spent 1,873 days in hibernation – about two-thirds of its flight time – spread over 18 separate hibernation periods from mid-2007 to late 2014 that ranged from 36 days to 202 days long.

In hibernation mode much of the spacecraft is unpowered; the onboard flight computer monitors system health and broadcasts a weekly beacon-status tone back to Earth. On average, operators woke New Horizons just over twice each year to check out critical systems, calibrate instruments, gather science data, rehearse Pluto-encounter activities and perform course corrections when necessary.

New Horizons pioneered routine cruise-flight hibernation for NASA. Not only has hibernation reduced wear and tear on the spacecraft’s electronics, it lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions.

Ready to Go

Next month’s wake-up call was preprogrammed into New Horizons’ on-board computer in August, commanding it come out of hibernation at 3 p.m. EST on Dec. 6. About 90 minutes later New Horizons will transmit word to Earth that it’s in “active” mode; those signals, even traveling at light speed, will need four hours and 25 minutes to reach home. Confirmation should reach the mission operations team at APL around 9:30 p.m. EST. At the time New Horizons will be more than 2.9 billion miles from Earth, and just 162 million miles – less than twice the distance between Earth and the sun – from Pluto.

Time to Wake Up: Artist’s impression of NASA’s New Horizons spacecraft, currently en route to Pluto. Operators at the Johns Hopkins University Applied Physics Laboratory are preparing to “wake” the spacecraft from electronic hibernation on Dec. 6, when the probe will be more than 2.9 billion miles from Earth. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
Time to Wake Up: Artist’s impression of NASA’s New Horizons spacecraft, currently en route to Pluto. Operators at the Johns Hopkins University Applied Physics Laboratory are preparing to “wake” the spacecraft from electronic hibernation on Dec. 6, when the probe will be more than 2.9 billion miles from Earth. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

After several days of collecting navigation-tracking data, downloading and analyzing the cruise science and spacecraft housekeeping data stored on New Horizons’ digital recorders, the mission team will begin activities that include conducting final tests on the spacecraft’s science instruments and operating systems, and building and testing the computer-command sequences that will guide New Horizons through its flight to and reconnaissance of the Pluto system. Tops on the mission’s science list are characterizing the global geology and topography of Pluto and its large moon Charon, mapping their surface compositions and temperatures, examining Pluto’s atmospheric composition and structure, studying Pluto’s smaller moons and searching for new moons and rings.

New Horizons’ seven-instrument science payload, developed under direction of Southwest Research Institute, includes advanced imaging infrared and ultraviolet spectrometers, a compact multicolor camera, a high-resolution telescopic camera, two powerful particle spectrometers, a space-dust detector (designed and built by students at the University of Colorado) and two radio science experiments. The entire spacecraft, drawing electricity from a single radioisotope thermoelectric generator, operates on less power than a pair of 100-watt light bulbs.

Distant observations of the Pluto system begin Jan. 15 and will continue until late July 2015; closest approach to Pluto is July 14.

“We’ve worked years to prepare for this moment,” says Mark Holdridge, New Horizons encounter mission manager at APL. “New Horizons might have spent most of its cruise time across nearly three billion miles of space sleeping, but our team has done anything but, conducting a flawless flight past Jupiter just a year after launch, putting the spacecraft through annual workouts, plotting out each step of the Pluto flyby and even practicing the entire Pluto encounter on the spacecraft. We are ready to go.”

“The final hibernation wake up Dec. 6 signifies the end of an historic cruise across the entirety of our planetary system,” added New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute. “We are almost on Pluto’s doorstep!”

The Johns Hopkins Applied Physics Laboratory manages the New Horizons mission for NASA’s Science Mission Directorate. Alan Stern, of the Southwest Research Institute (SwRI) is the principal investigator and leads the mission; SwRI leads the science team, payload operations, and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Ala. APL designed, built and operates the New Horizons spacecraft.

Source: JHUAPL

These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan.
Image Credit: NASA/JPL-Caltech/ASI/Cornell

Cassini Watches Mysterious Feature Evolve in Titan Sea

By Preston Dyches


 

NASA’s Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn’s moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini’s radar experiment, but its appearance changed between the two apparitions.

Images of the feature taken during the Cassini flybys are available at:

http://photojournal.jpl.nasa.gov/catalog/PIA18430

The mysterious feature, which appears bright in radar images against the dark background of the liquid sea, was first spotted during Cassini’s July 2013 Titan flyby. Previous observations showed no sign of bright features in that part of Ligeia Mare. Scientists were perplexed to find the feature had vanished when they looked again, over several months, with low-resolution radar and Cassini’s infrared imager. This led some team members to suggest it might have been a transient feature. But during Cassini’s flyby on August 21, 2014, the feature was again visible, and its appearance had changed during the 11 months since it was last seen.

Scientists on the radar team are confident that the feature is not an artifact, or flaw, in their data, which would have been one of the simplest explanations. They also do not see evidence that its appearance results from evaporation in the sea, as the overall shoreline of Ligeia Mare has not changed noticeably.

The team has suggested the feature could be surface waves, rising bubbles, floating solids, solids suspended just below the surface, or perhaps something more exotic.

The researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon’s northern hemisphere. Monitoring such changes is a major goal for Cassini’s current extended mission.

“Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan,” said Stephen Wall, the deputy team lead of Cassini’s radar team, based at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We’re hopeful that we’ll be able to continue watching the changes unfold and gain insights about what’s going on in that alien sea.”

These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. Image Credit: NASA/JPL-Caltech/ASI/Cornell
These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn’s moon Titan.
Image Credit: NASA/JPL-Caltech/ASI/Cornell

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

Source: NASA