New Horizons Hibernation and Cruise to Pluto Options

[Guest_AlexBlackwell_*]

I thought I'd kick off a new thread with this announcement:

New Horizons Slips into Electronic Slumber
June 28, 2007

[Alan Stern]

..this will be coming out later in the week sports fans; I thought USMFers would like to see it first.

“Outbound at 7 AU”

Alan Stern
01 August 2007


IMAGE: New Horizons launched just over 18 months ago on a journey that will take 114 months to reach the Pluto system. (NASA photo.)


Since I last wrote here, in mid-June, New Horizons has been continuing its speedy journey across the space from Jupiter’s orbit at 5.2 AU to Saturn’s at 9.5 AU. On average, we travel about a third of an astronomical unit each month, or roughly a million miles per day. So as July turns into August, we’re nearing the half-way point in the Jupiter-Saturn leg of our journey, reaching 7 AU on 6 August. We’ll pass Saturn’s orbit (but not Saturn, which will be far away from our path) next April.

During the six weeks since I last wrote, the spacecraft has primarily been in hibernation. In fact, since June 27th we’ve been in hibernation except for a brief, 9-day wake up that began on July 12th.

The highlight of the mid-July wake up period was the opening of the solar occultation port (SOCC) on the Alice UV spectrometer (UVS). This was the last of the seven instrument aperture doors to be opened on New Horizons. Like all the other openings, this one also went smoothly. Now, Alice can use its pinhole-sized SOCC aperture to stop down the intensity of sunlight by a factor of about 6000, making it possible to trace the density and composition of Pluto’s atmosphere versus altitude without blinding the detector. After opening the Alice SOCC door, the spectrometer gathered its first-light SOCC spectrum by observing the B star Bellatrix. The Alice UVS also performed a series of self tests and also received a software update during the wakeup.


IMAGE: The New Horizons Alice UV spectrometer showing the Solar Occultation port as the black protuberance near center bottom; the main Alice aperture is the much larger black aperture protruding from the instrument’s right side. (Credit: SwRI)


Other activities during the July wake up included onboard data compression testing, some LORRI and SWAP instrument tests, and a data dump of the Venetia Burney Student Dust Counter’s data memory. New Horizons was returned to its hibernation state on July 21st and will remain in hibernation until August 16th when we wake up for about three months of intensive onboard activities that will include numerous instrument calibrations and tests and a small course correction maneuver (see my previous PI Log). Until then, we will listen to its telemetry or beacon tone broadcasts four times per week, but we won’t be actively controlling the spacecraft; all commands it executes were stored in onboard memory before entering this second hibernation period.

But while our spacecraft slumbers, our ground team is busy planning those activities for the wake up period, which will stretch into mid-November. And, simultaneously, our science team continues to analyze Jupiter data and work to select a final targeting distance for our Pluto closest approach. I’ll have more to say about that next time I write. For now, however, I want to tell you that in early July the team completed a series of 8 scientific papers about some of the most important Jupiter system results we achieved, and then submitted those papers to the journal Science for publication in a special section issue this fall. And while the spacecraft and science teams kept busy as I just described, engineers working on New Horizons are busy building a second New Horizons Operations Simulator (“NHOPS II”) which will serve as both an insurance policy against the failure of NHOPS I during the long flight to Pluto and the Kuiper Belt, and also as a “surge” simulator for times when NHOPS I is booked up. NHOPS II, replete with high-fidelity engineering models of the instrument payload and the spacecraft subsystems, will be completed and then extensively checked out early next year.

In other project news, it is my pleasure to tell you that our project manager, Glen Fountain, has been selected to receive the American Institute of Aeronautics and Astronautics (AIAA) 2007 von Braun Award for Excellence in Space Program Management. This award gives national recognition to an individual for outstanding contributions in the management of a significant space or space-related program or project. I think Glen was an obvious choice, but I am biased, of course. Nonetheless, we’re all proud of him and look forward to Wednesday, 19 September when he’ll be presented with the award in conjunction with the AIAA Space Conference and Exhibit, Long Beach Convention Center, Long Beach, California.


IMAGE: New Horizons Project manager Glen Fountain; Sunday 15 January 2006. (Credit: Alan Stern)


Well, that’s what I wanted to tell you about this time. I’ll be back with more news in another update in September. In the meantime, keep on exploring, just like we do.

-Alan Stern