Reposted from https://blogs.nasa.gov/mission-ames/2013/07/23/pluto-king-of-the-kuiper-belt-prince-of-the-plutinos-certainly-an-object-that-inspires-odes-songs-and-ballads/.

After the New Horizons’ instrument overviews on the first day at the Pluto Science Conference (Jul 22, 2013, we jumped right into Pluto in the Kuiper Belt Context.

Brett Gladman (University of British Columbia, Vancouver, Canada) started the conversation by addressing “How does Pluto fit in our understanding of the Kuiper Belt?”

But before we get into that, discussing the Kuiper belt today can be pretty complex. It was only discovered in 1992, but in the years since, over 130,000 bodies with sizes 100 km and larger have been identified (Petit et al 2011), with Pluto being the largest member.

So when we start looking at large numbers of objects, it’s time to classify. So a typical plot to describe these “populations” is shown below, where semi-major axis (distance of body from the Sun) is plotted (horizontal axis, labeled ‘a’ in units AU, where 1 AU is the distance of the Earth from the Sun, Jupiter is ~5 AU, Saturn ~10AU) versus eccentricity (value between 0 and 1 that describes how circular an orbit it, e=0 is circle, e=1 is parabola, 0<e<1 describes ovals).

And then you have your Classical, your Cold Classical, Hot Classical, Detached, Resonant, and SDO (aka Scattered Disk Objects), etc. Sometimes they group together, others are more uniform across the parameter space.

Kuiper Belt in “a/e space.” Cold classical (black open triangles). Resonant Kuiper (open red square). Detached (blue triangles). Pluto is indicated with the yellow-box, it’s a Resonant, as it is in 3:2 Resonance with Neptune. This group of objects, all in 3:2 Resonance with Neptune are the “Plutinos.” (that clumping around 40 AU, red triangles, spanning over a range of e). Resonance numbers are shown at the top of the graph.

Plutinos are also a family of TNOs, Trans-Neptunian Objects, characterized by being in 3:2 mean-motion resonance with Neptune (i.e., every time Neptune makes 3 trips about the Sun, the Plutinos make 2 trips). Plutinos are the most dominant of the TNOs. Less numerous are the 1:1 objects, objects known as Trojans.

Definitely KBO soup!

For more information about TNOs and their period relationships with Neptune https://en.wikipedia.org/wiki/Resonant_trans-Neptunian_object.

After getting down those nomenclature basics, Brett Gladman (who is also lead for a huge ground-based survey of KBOs called the Canada-France Ecliptic Plane Survey/CFEPS) discussed the strengths and pitfalls of the theories put forward to explain the formation and structure of this complex KBO menagerie.

For more information about CFEPS check out http://www.cfeps.net/.

How did Pluto get to where it is today? Two leading theories (1) Resonant sweeping of objects formed in TNO regions and (2) resonant trapping explain many things, but no published models explain those resonant structures of the Kuiper belt. And any of these models have issues with the classical and scattering disk populations as well. Theorists, better sharpen your pencils.

So he left us with questions to ponder. Is there a cold primordial Kuiper Belt with edge at 45 AU? Did Pluto likely form as one of hundreds to thousands of >1000km embryos? Did some of these become implanted into the nearby non-scattering belt? Are there others out beyond 100 AU (considered likely, but to discover them, you need to get down to 23-24^th mag which is beyond the current survey capabilities until new telescopes and.or techniques come available)?

No doubt, searches for more TNOs will continue, the classification of the KB will undergo evolution, and theorists will refine their models. And New Horizons will provide a unique data set of an up-close-and-personal visit to Pluto and its companions to help constrain those models.

Putting Centaurs and TNOs in Context. This time plotting inclination (the degrees from the ecliptic plane) vs. semi-major axis in AU. Object sizes are reflected in the symbol sizes. Location of Saturn, Uranus and Neptune are shown. Just another way to look at that awesome & diverse Outer Solar System. From: https://en.wikipedia.org/wiki/Trans-Neptunian_object.

Next, Cesar Fuentes (Arizona State) phoned in about his work on the “Size Distribution (SD) of the Kuiper Belt.” Size distribution is basically counting the number of objects as a function of size.  Coagulation (of small particles) and gravitation instability (of larger particles) shape the size distribution. Size distribution is expected to change due to collisions. Different distances from the sun also appear to have different size distributions.

He stepped us through recent size distribution models from Schlichting, Fuentes & Trilling (2013) and Kenyon & Bromley (2013) where they even have some including the “collisional factor” influence on the size distribution over time periods.

All the Size Distributions show a “rollover” around H~9, D=70km. Nesvorny et al. 2013 investigates this further. Is the break due to collisional and therefore separate the primordial from the evolved KBO populations?

Even more questions to ponder:  Can we use size distributions to evaluate primordial from the evolved KBO populations?

And then he left us with a tantalizing experiment with the New Horizons mission: If New Horizons can provide data sets enabling “crater counting,” we will be able to measure the impactors on Pluto. This can aid in understanding KBO populations, addressing specifically, formation time, timescales for surface activity, and origins of bodies like Nix & Hydra. What would a 0.1-100 km impactor size distribution look like?

Pluto, be it Prince of the Plutinos or King of the Kuiper Belt, will always remain a key part to these questions above. And data sets from New Horizons will provide many new angles to answering questions about “Where did Pluto form and why did it wind up where it is now.”

Reposted from https://blogs.nasa.gov/mission-ames/2013/07/23/introducing-the-new-horizons-instrument-menagerie/.

During the first day of the Pluto Science Conference, being held July 22-26, 2013, in Laurel, MD, the conference participants listened to a series of talks describing the rich instrument suite aboard the New Horizons Spacecraft. This entry is just a very brief synopsis of the instruments.

Ralph, Alice, MVIC, LEISA, LORRI, REX, SWAP, PEPSSI, SDC. Those are instrument names and acronyms of the New Horizons science instruments.

LORRI (Long Range Reconnaissance Imager), among many things, “Enables Far-Out Encounter Science. ” That is, at 10 weeks from closest approach, LORRI can observe the Pluto system with spatial resolution better than Hubble. It is a visible camera, equipped with a 1024 x 1024 pixel CCD, with a 0.29 x 0.29 degree field of view (5 microradian pixel iFOV). LORRI also will be used, on approach, for optical navigation. The LORRI Instrument Principal Investigator and Instrument Scientist is Andy Cheng (JHU/APL) and Hal Weaver (JHU/APL), respectively.

Ralph & Alice form New Horizons’  “Remote Science Suite.” Ralph is both a color-imager (MVIC) and an infrared mapping spectrometer (LEISA). Alice is a ultraviolet spectrometer.

Ralph’s MVIC (Multi-Spectral Visible Imaging Camera) consists of seven independent CCD arrays. Four channels are filtered to map blue (400-550 nm), red (540-700 nm), near infrared (780-975 nm) and a narrow methane absorption band (860-910 nm). Six of the MVIC arrays (including all the filter channels) have a 5.7 x 0.037 degree field of view (20 microradian pixel iFOV). LEISA (Linear Etalon Imaging Spectral Array) is a grating spectrometer covering 1.25 to 2.5 microns wavelength range at a resolving power of R~240. A second segment covers 2.1 to 2.25 micron range with a resolving power of R~560. The Ralph Instrument Principal Investigator and Instrument Scientist is Alan Stern (SwRI) and Dennis Reuter (NASA Goddard), respectively.

Alice is an ultraviolet imaging spectrometer. It has two entrance apertures, a large airglow channel and a small SOCC aperture for solar occultation measurements. The entrance slit has two sections, a “box” with a 2.0 x 2.0 degree field of view, and a “stem” with a 0.1 x 4.0 degree field of view. The wavelength coverage spans from 520 to 1870 Angstroms, with a resolution of 3.6 Angstroms.  The Alice Instrument Principal Investigator and Instrument Scientist is Alan Stern (SwRI) and Maarten Versteeg (SwRI, San Antonio), respectively.

REX, New Horizons’ Radio Science Experiment, is enabled by adding a small amount of signal processing hardware to the existing communication hardware on New Horizons’ main antenna. It will be used, among other observations of Pluto, to showcase a “Different Kind of Radioscience” via 20kW uplink experiments from the DSN during the Pluto and Charon occulations at flyby. The REX Principal Investigator and Instrument Scientist are G.L. Tyler and Ivan Linscott (Stanford University), respectively.

PEPSSI (Pluto Energetic Particle Spectrometer Science Investigation) & SWAP (Solar Wind Around Pluto) are modern particle instruments designed to capture Pluto’s interaction with the solar wind. PEPSSI can measure ions and electrons from 10s of keV to 1 MeV over a 160 x 12 degree fan-shapped beam. SWAP can measure particles with energies 35 eV to 7.5 keV over a 276 x 10 degree field of view. PEPSSI’s Principal Investigator and Instrument Scientist are Ralph McNutt (JHU/APL) and Matthew Hill (JHU/APL). SWAP’s Principal Investigator and Instrument Scientist are David McComas (SwRI, San Antonio) and Heather Elliott (SwRI, San Antonio).

SDC, the Student Dust Counter, designed and built by students at the University of Colorado, Boulder, is “The First Student Experiment on a Deep-Space Probe.” The Principal Investigator is Mihaly Horanyi (University of Colorado). There have been numerous Instrument Scientists, all students at Univ. of Colorado. The current Instrument Scientist is Jamey Szalay. Students continue to be active in supporting data analysis as SDC collects dust rates on its voyage through the solar system. More information about the SDC and the students behind it at http://lasp.colorado.edu/sdc/.

More details about each of the instrument descriptions and performance can be found at http://pluto.jhuapl.edu/Mission/Spacecraft/Payload.php.

 

Reposted from https://blogs.nasa.gov/mission-ames/2013/07/22/initial-reconnaissance-of-the-solar-systems-third-zone/.

This is part of a blog series on the Pluto Science Conference, “The Pluto System on the Eve of Exploration by New Horizons: Perspectives and Predictions,” held July 22-26, 2013 in Laurel, MD.

New Horizons’ Principal Investigator (lead scientist) is Dr Alan Stern (SwRI/Southwest Research Institute). In his presentation, he gave an overview of the mission concept, the science objectives and mission status. The scientific suite is sophisticated and carries the first student-built deep space instrument. The cruise period spans two Presidential administrations (8 years). New Horizons launched on January 19, 2006, and will fly by the Pluto system with closest approach July 14, 2015.

For more information about the mission, do check out the New Horizons Mission Websites: http://pluto.jhuapl.edu/ (JHU APL site) and http://www.nasa.gov/mission_pages/newhorizons/main/index.html. (NASA site).

Measurement-wise, New Horizons’ Pluto fly-by of July 2015 is comparable to Voyager 2’s fly-by of Neptune’s moon Triton in 1989. However, Voyager 2 did not have an infrared mapping nor ultraviolet imaging spectrometer, something New Horizons will have. Also, New Horizons will be flying three times closer to Pluto than Voyager 2 did at Triton.  A snapshot of the comparison highlights from Alan’s talk is below.

The New Horizons’ unique science encounter involves more than 6 months of active science operations, starting in mid-April 2015 when the on-board instrument suite achieves resolution better than Hubble.

A more in depth discussion about “When will New Horizons have better views of Pluto than Hubble does?” can be found in this blog entry on the Planetary Society’s blog site at http://www.planetary.org/blogs/emily-lakdawalla/2013/0218-new-horizons-pluto-better-hubble.html .

For more in-depth information about the New Horizons mission check out a series of a papers published in Space Science Reviews.  Link: http://www.boulder.swri.edu/pkb/

To end this posting, a few fun factoids about New Horizon’s Speedy Performance since Launch.

New Horizons’ Speed Record. Launched on an Atlas V-551 on January 19, 2006 at 14:00 EST, the ~400 kg spacecraft, about the size of a grand-piano, needs to travel 5 billion km (5x10e9 km) from Earth before it can execute the observations for its prime science mission. Launching with a speed of  58,000 km/hr (36,000 mph) and benefiting from a gravity-assist from Jupiter in February 2007 (which boosted the spacecraft speed), New Horizons will reach its destination, Pluto, after ~9.5 years of space flight.

New Horizons Speed Facts:
Launched at 36,000 mph
Passed Moon’s orbit in 9 hours
Passed orbits of:
Mars on 4/7/2006
Jupiter on 2/28/2007
Saturn on 6/8/2008
Uranus on 3/18/2011
To cross orbit of:
Neptune on 8/24/2014
With closest Approach Pluto-Charon on 7/14/2015

Reposted from https://blogs.nasa.gov/mission-ames/2013/07/22/new-horizons-a-mission-for-the-patient-and-persistent/.

New Horizons is a Mission for the Patient (and Persistent). It is a labor of love, dedication, fortitude, with compelling science, top-notch engineering, and tight management. This is an entry part of a blog series covering the Pluto Science Conference, held July 22-26, 2013 in Laurel, MD.

Tom Krimigis (JHU/APL) started off our excited Pluto crowd with an overview of the steps that enabled the New Horizons mission to become reality. Any science mission starts with its science objectives. Successful science mission concepts that make it to launch rely on thorough reviews of its science, engineering, and investment (i.e. cost & feasibility).  New Horizons, owes its existence to both initial scientific grounding work by the scientists in the 1970s and equally also to the persistence of those scientists and supporters at NASA and Congress over the subsequent decades to make it get to flight. New Horizons was selected in November 2001 from a competition and launched in January 2006. It will reach its destination, the Pluto-Charon system in 2015.

A rose by any other name is still a rose. A mission to Pluto has had many names over these past decades and with concepts “varying on a theme.” It was called Mariner-Jupiter-Pluto (MJP), mini Voyager-Pluto Fast Flyby (PFF), Pluto Express-Pluto-Kuiper Express, and now New Horizons, among many mission names.

For more reading about the saga, science, and significance of Pluto exploration, check out Andrew Lawler, Science 295, 32-36, Jan 4, 2002. “Planetary Science’s Defining Moment.” at http://www.sciencemag.org/content/295/5552/32.full.pdf  (requires login access) or find it here from the author’s website.