New Horizons has One Last Sleep til Pluto

On Aug. 25, New Horizons crossed the orbit of Neptune-the last planetary orbit crossing during cruise.

Now the spacecraft is outbound for Pluto.

On Aug. 29 the team put New Horizons into hibernation for the final time, prior to its encounter with Pluto.

This last hibernation lasts 99 days and ends on Dec. 6.

After seven-plus years of hibernating through most of the 2.5-billion mile journey from Jupiter to Pluto and the inner reaches of the Kuiper Belt, the spacecraft has reached the final, short leg of cruise.

New Horizons will be re-awakened for the last time in just 10 weeks. Once this has been done, 'encounter' preparations will begin, and six weeks later, the Pluto encounter itself will begin.

At that time, the New Horizons team will have good cause to celebrate. They will have reached the outer end of our Solar System, twenty-five years after first wondering if Pluto might someday be explored.

This summer's eighth and final "pre-Pluto" spacecraft and payload Active Check Out (ACO-8) lasted from June through late August. All spacecraft subsystems-both prime and backup-were checked out and were found to be operating successfully.

Additionally, the team performed their first course-correction since 2010, uploaded the final autonomy system software for the encounter, checked out all seven payload instruments, conducted some final instrument calibrations, and performed their first optical navigation campaign to home in on Pluto using New Horizons' Long Range Reconnaissance Imager (LORRI).

Those activities went well, and so did many others, including more sampling of the heliospheric plasma and dust environment with PEPSSI, SWAP and Student Dust Counter instruments.

The only real anomaly of the entire ACO-8 was a failed startup of a single Alice ultraviolet spectrometer observation.

That observation was to study the distribution of interplanetary hydrogen near Neptune's orbit; it failed because Alice was much colder than was planned, and onboard software "safed" (or turned off) Alice's high-voltage power supply when it took too long to get to its set point voltages.

The team have now learned that they need to adjust some timing settings for future power-ons when Alice will be as cold or even colder, On its approach to Pluto.

Additionally, ACO-8 was the subject of a recent news story from New Horizons: While testing the methods to be used to search for hazards in the Pluto system on approach, the spacecraft detected Pluto's little moon Hydra.

The team didn't think it would be possible to see Hydra until early in 2015, when the spacecraft was much closer, but science team members John Spencer and Hal Weaver found Hydra in the July hazard-sequence test.

The New Horizons team sees the early detection of Hydra as good news, because it anticipates their ability to detect currently unknown moons and rings close to Pluto.

ESA Rosetta Mission: Waking up from Hibernation

Philae landing on comet

Next year, on 20 January, after 957 days of hibernation in deep space, ESA’s comet-chasing Rosetta spacecraft is set to wake up automatically en route to the destination it has been travelling towards for nearly a decade.

In preparation for the critical activation and the challenges that lie ahead for Rosetta, members of the media are invited to a briefing by ESA’s science and mission control experts and partners on Tuesday, 10 December, 10:00–12:30 CET, at ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany.

The 20 January milestone will mark the start of an intensive year as Rosetta draws steadily closer to comet Churyumov–Gerasimenko ahead of rendezvous in August.

After extensively mapping the comet’s surface, it will dispatch the lander Philae in November for close-up study of the nucleus.

Rosetta will then follow the comet on its journey through the inner Solar System, monitoring the ever-changing conditions as it warms up heading towards its closest approach to the Sun, in August 2015.

Rosetta’s main objective is to help understand the origin and evolution of the Solar System, in particular investigating the role that comets may have played in seeding Earth with water, and perhaps even life.