Chasing New Horizons

by Alan Stern

  EVIDENCE FOR A POSSIBLE LIQUID WATER OCEAN INSIDE PLUTO TODAY

  The giant glacier on Pluto called Sputnik Planitia is located almost exactly at the “anti-Charon point.” That is, it is centered almost exactly opposite from the location on Pluto where Charon, being tidally locked, always hangs directly overhead. Why should it be precisely there? It’s thought that the added weight of the ice in the Sputnik Planitia basin itself might have led to tidal forces that caused the basin to migrate into that position. However, that can only occur if the interior of Pluto and the planet’s icy crust are “frictionally decoupled” by the existence of a liquid water ocean layer below the crust. Definitive tests for an interior ocean will have to wait for a future orbiter mission to Pluto, but even now we can ask, might this water ocean be inhabited? Could there be Plutonian life forms swimming deep underneath the planet’s icy surface? Current thought within astrobiology holds that liquid water may be a key necessity for life, with organic molecules and some form of energy flow also required. It seems possible that all these conditions could be met within Pluto, as it is within other worlds with interior oceans, like Europa and Enceladus.

  CHARON’S ENORMOUS EQUATORIAL TECTONIC BELT, HINTING AT AN ANCIENT INTERIOR OCEAN

  Separating the northern from the southern hemispheres of Charon, and slanting at a sharp angle across the equator from the southwest to the northeast, is a huge complex of valleys and cliffs that stretch for over one thousand miles. Geological analysis reveals that this is a huge extensional belt, meaning that the surface of Charon was pulled apart across this yawning series of chasms by expansion forces. What would have caused Charon to split down the middle like that? In order to generate the forces sufficient to break apart its solid surface, it appears that Charon would have had to expand on the inside, like a beverage can that bursts when you leave it in the freezer for too long. What actually happened is probably similar to that. Charon’s interior is about half water ice by mass, and we know that when Charon formed, its interior was hot, causing the water ice to be liquefied. Over time, as it cooled, the freezing process caused internal expansion, which in turn likely resulted in the creation of the widespread tectonic belt we see.

  CHARON’S COMPLETELY UNIQUE, DARK, RED POLAR CAP

  Perhaps Charon’s most remarkable surface feature is its dark, reddish polar cap, also sometimes called a polar “stain,” as it appears to be diffusely spread—almost sprayed on top of its underlying polar geology. Nothing like it has been seen anywhere else among all the other worlds of our solar system. The leading idea to explain the red cap is that some of the methane escaping off the top of Pluto’s atmosphere strikes Charon and preferentially condenses on Charon’s poles, the coldest places on this moon. As has been simulated in scientific laboratories on Earth, on Charon the methane can be processed by sunlight and solar wind into heavier hydrocarbon molecules which are dark and red—just as is observed on Charon’s poles—and which are nonvolatile, meaning they don’t evaporate. This strange connection between Pluto and Charon, with material from Pluto slowly migrating to Charon over the eons, is reminiscent of some kinds of binary stars that exchange material with one another gravitationally, and it adds to the oft-stated description of the Pluto system as a sci-fi lover’s dream!

  SMALL MOON MYSTERIES

  Every aspect of the Pluto system contains its share of surprises. This has even been true of Pluto’s four small moons—Nix, Hydra, Styx, and Kerberos—which orbit outside the Pluto-Charon binary. One surprising discovery about these small moons is how fast they are all spinning, much faster than their orbital periods. Hydra, the most extreme, rotates in just ten hours—almost one hundred times faster than its orbital period. Even stranger, their spin axes are not basically perpendicular to their orbital planes around Pluto, the norm in other systems of moons. Why? The answer is unknown. All four of these small satellites have the elongated, non-spherical shapes that are typical of icy objects not large and massive enough to pull themselves into a sphere with their own gravity. But yet another surprise is that two of them—Styx and Hydra—are each composed of two “lobes” that appear smashed together, which may be telling us that they formed by collisions of former moons. And if that’s not enough, all four of Pluto’s small moons are also surprisingly bright and reflective: they each reflect about 70–80 percent of the light that strikes them, which makes them among the most reflective objects in the solar system. And a final mystery is that despite an intense search for smaller moons by New Horizons, none were found. Given that almost every time the Hubble Space Telescope looked for new moons around Pluto, it found them, it surprised almost everyone on the New Horizons team that they didn’t find more when the spacecraft was close enough to beat Hubble’s capabilities. Why does Pluto have five moons and yet no more? No one knows.

  ACKNOWLEDGMENTS

  First and foremost, we wish to acknowledge the New Horizons team members, and the current and former NASA officials, and others, who agreed to be interviewed and quoted. Each generously lent us their time and insights; without their contributions this book would have not been possible. For this we particularly thank Fran Bagenal, Alice Bowman, Marc Buie, Glen Fountain, Dan Goldin, Mike Griffin, Chris Hersman, Wes Huntress, Tom Krimigis, Todd May, Bill McKinnon, Ralph McNutt, Jeff Moore, Cathy Olkin, John Spencer, Rob Staehle, Hal Weaver, and Leslie Young. We are also extremely grateful to all of the contributors to the success of New Horizons and the exploration of Pluto.

  For other helpful conversations and correspondence, we thank Jim Bell, Laurie Cantillo, Candy Hansen, Charles Kolhase, Jonathan Lunine, Kelsi Singer, Joel and Leonard Stern, Chuck Tatro, the Tombaugh family, Stacy Weinstein, and Amanda Zangari. We are also indebted to Cindy Conrad, who was massively helpful to us, both logistically and editorially. And we also thank Morgaine McKibben, Michael Soluri, and Henry Throop for photographically capturing aspects of the New Horizons mission and allowing us to use their beautiful and oftentimes touching images. Thanks, too, to Kevin Schindler, Historian at Lowell Observatory, who generously shared with us archival materials that enriched this book, and Mike Buckley of the Applied Physics Laboratory, who gave invaluable help tracking down and providing NASA and APL images and other material. We also want to thank our agents, Carrie Hannigan, Josh Getzler, and Eric Lupfer, for skillfully guiding us through all the stages of this project, and to our editor, James Meader, for his constant encouragement, patience, and judgment, and for joining us in our excitement at sharing the story of New Horizons with the world. Finally, we thank our wives, Jennifer Goldsmith-Grinspoon and Carole Stern, for putting up with the many long weekends and evening hours that went into writing this book.

  INDEX

  The index that appeared in the print version of this title does not match the pages in your e-book. Please use the search function on your e-reading device to search for terms of interest. For your reference, the terms that appear in the print index are listed below.

  Academy of Motion Picture Arts and Sciences

  Aerojet Rocketdyne

  AGU. See American Geophysical Union

  Aldrin, Buzz

  “Alice” ultraviolet spectrometer

  American Astronomical Society

  American Geophysical Union (AGU)

  Anomaly Review Boards (ARBs)

  “antenna-to-ram” technique

  Apollo missions

  Applied Physics Laboratory, Laurel, Maryland (APL)

  NEAR mission by

  New Horizons’ development, management of, by

  New Horizons’ mission control at

  New Horizons’ project bid by

  NHOPS simulator at

  Approach Phases 1-3, Pluto flyby

  ARBs. See Anomaly Review Boards

  Armstrong, Neil

  Atlas Spaceflight Operations Center (ASOC)

  Atlas V rocket, launch with

  atmosphere, Pluto

  atmospheric pressure in

  haze observed in

  loss of />
  Atmospheres Team, New Horizons

  Baez, Omar

  Bagenal, Fran

  plasma/particle measurement by

  Pluto mission research by

  in Pluto Underground

  Ball Aerospace

  Bauer, Brian

  Beebe, Reta

  Binzel, Richard “Rick”

  Blaine, David

  blink comparators

  Boeing

  Bogan, Denis

  Bolden, Charles

  Bowman, Alice

  New Horizons’ computer crisis and

  New Horizons’ launch and

  New Horizons’ navigation oversight by

  New Horizons’ proposal contributions by

  Pluto flyby planning/execution by

  Briggs, Geoff

  Brown, Mike

  Buie, Marc

  KBO search by

  in Pluto Underground

  Burney, Venetia

  Burratti, Bonnie

  Bush, George H. W.

  Bush, George W.

  Calloway, Andy

  Cantillo, Laurie

  Cape Canaveral. See Kennedy Space Center, Cape Canaveral, Florida

  Cassini mission

  “antenna-to-ram” technique used in

  CBS News

  Centaur launch stage

  Certificate of Flight Readiness (COFR)

  Challenger space shuttle

  Charon (Pluto moon). See also top discovery(ies), New Horizons

  discovery of

  eclipse of Pluto by

  geographical/geological findings on

  mission objectives for

  orbit of

  size of

  top New Horizons discoveries on

  Christy, James “Jim”

  Clarke, Arthur C.

  Cleave, Mary

  Clyde Tombaugh Elementary School, New Mexico

  COFR. See Certificate of Flight Readiness

  Cold War

  Communications Plan, NASA

  Composition Team, New Horizons

  configuration management (CM)

  Conrad, Cindy

  Contour spacecraft

  Core phase, Pluto flyby

  computer malfunction prior to

  Encounter Mode during

  “fail-safe” data retrieval during

  high-resolution imaging during

  optical navigation for

  simulations of

  upload of commands for

  Coughlin, Tom

  Cronkite, Walter

  Cthulhu (Pluto’s “whale”)

  Dantzler, Andy

  Decadal Survey

  Deep Space Network, NASA

  Delta II rockets

  Delta IV rockets

  Department of Atmospheric and Planetary Sciences, University of Colorado

  Department of Defense (DOD)

  Department of Energy (DOE)

  RTG powering by

  Departure Phases 1-3, Pluto flyby

  Discovery Program, NASA

  Division of Planetary Sciences (DPS)

  DOE. See Department of Energy

  DPS. See Division of Planetary Sciences

  Drake, Mike

  Durda, Dan

  Elachi, Charles

  Emmart, Carter

  Enceladus (Saturn moon)

  Encounter Change Control Board (ECCB), New Horizons

  Encounter Mode, Pluto flyby

  EPA

  Eris (dwarf planet)

  Eros asteroid

  Esposito, Larry

  Europa (Jupiter moon)

  conditions for life on

  Facebook

  fail-safe data plan, New Horizons

  “Faith of the Heart” (song)

  Farquhar, Robert

  Fast Flyby Pluto mission proposal

  Fountain, Glen

  New Horizons’ computer malfunction and

  as New Horizons’ development project manager

  New Horizons’ hazard-watch campaign and

  New Horizons’ optical navigation and

  nuclear launch approval oversight by

  Pluto flyby task scheduling by

  Francois, Steve

  Friedman, Lou

  Galeev, Alec

  Galileo mission

  “antenna-to-ram” technique used in

  Gemini constellation

  Gemini missions

  geography, Pluto

  active status of

  liquid water potential and

  mountains within

  nitrogen glacier within

  Geology and Geophysics Team, New Horizons

  Gerstenmaier, Bill

  Geveden, Rex

  Giacconi, Riccardo

  Gibson, Bill

  as New Horizons’ payload/instrument project manager

  Gladstone, Randy

  “Glen’s Glide” flight phase, New Horizons

  Goddard Space Flight Center, Greenbelt, Maryland

  Goldin, Dan

  “Grand Tour” mission concept, NASA

  gravity assists

  by Jupiter

  Green, Jim

  Griffin, Mike

  Grundy, Will

  Grunsfeld, John

  Halley’s Comet

  Hersman, Chris

  malfunction procedures development by

  New Horizons’ computer crisis and

  as New Horizons’ spacecraft engineering lead

  hibernation mode, New Horizons

  Hillary, Edmund

  Hillary Montes (Pluto mountains)

  Holdridge, Mark

  on ECCB committee

  and ground logistics, Pluto flyby

  as New Horizons’ Pluto flyby mission manager

  New Horizons’ timing update and

  Honeymooners (TV show)

  Honeywell

  Hubble Space Telescope

  Hunten, Donald

  Huntress, Wes

  Hydra (Pluto moon)

  discovery of

  formation of

  shape/rotation of

  size and composition of

  IAU. See International Astronomical Union

  Idaho National Lab

  Inertial Measurement Units (IMUs)

  Instagram

  International Astronomical Union (IAU)

  “planet” definition by

  Io (Jupiter moon)

  “IRIS” composition spectrometer

  Journal of Geophysical Research

  JPL

  New Horizons’ development and role of

  Pluto mission bids by

  Jupiter

  Gravity Assist

  magnetosphere radiation of

  NASA missions to

  New Horizons’ study of

  Jupiter Encounter Science Team, (JEST) New Horizons

  KBOs. See Kuiper Belt Objects

  Kennedy Space Center, Cape Canaveral, Florida

  New Horizons’ launch from

  as wildlife sanctuary

  Kerberos (Pluto moon)

  discovery of

  shape/rotation of

  Krimigis, Stamatios “Tom”

  Kubrick, Stanley

  Kuiper Belt

  Eris’s discovery in

  New Horizons’ mission objectives for

  Kuiper Belt Objects (KBOs)

  2014 MU69

  New Horizons’ flyby of

  Kuiper, Gerard

  Lappa, Linda

  Levison, Hal

  Lewis and Clark

  Lockheed Martin

  LORRI (Long Range Reconnaissance Imager)

  Los Alamos National Laboratory

  work shutdown at

  Lowell, Constance

  Lowell Observatory

  Pluto’s discovery at

  Lowell, Percival

  Lucas, George

  Lunar and Planetary Laboratory

  Lunine, Jonathan

  Magellan mission

  malfunction procedures development, New Ho
rizons

  Mariner missions

  technical capabilities of

  Mars

  Climate Orbiter

  NASA missions to

  Observer, explosion of

  Marsden, Brian

  Marshall Space Flight Center, Huntsville, Alabama

  “Mars Underground”

  Martin Marietta

  May, Brian

  May, Todd

  McAuliffe, Christa

  McKinnon, William “Bill”

  McLeish, John

  McNamee, John

  McNutt, Ralph

  MCR. See Mission Confirmation Review

  Mercury

  NASA missions to

  MESSENGER spacecraft

  Mikulski, Barbara

  Mission Confirmation Review (MCR)

  missions, NASA. See also New Horizons mission

  Apollo

  Cassini

  Challenger

  Galileo

  Gemini

  Magellan

  Mariner

  Mars Observer

  Pioneer

  Viking

  Voyager

  MOC, (Missions Operations Center), New Horizons

  backup functions at

  mission launch and

  New Horizons’ computer malfunction and

  Pluto flyby management by

  Moon (Earth’s)

  Moore, Jeff

  as New Horizons’ Geology and Geophysics Team leader

  MOPS (mission operations) Team, New Horizons

  Morgan, Tom

  NASA. See also New Horizons mission

  Apollo missions by

  Cassini mission by

  Challenger mission by

  Deep Space Network of

  Discovery program by

  Galileo mission by

  Gemini missions by

  “Grand Tour” mission concept by

  Magellan mission by

  Mariner missions by

  Mars Observer mission by

  media/publicity plans by

  mission selection process by

  “New Frontiers Program” by

  New Horizons’ launch by

  New Horizons’ Pluto flyby operations and

  and New Horizons’ post-Pluto objectives

  New Horizons’ project development and

  Pioneer missions by

  Pluto/Kuiper Belt missions, future, by

  Pluto mission competitions by

  Pluto mission study by

  standardization of spacecrafts by

  Viking missions by

  Voyager missions (Mariner Jupiter-Saturn) by

  National Academy of Sciences

  National Air and Space Museum, Dulles, Virginia

  National Geographic

  Nature

  NEAR (Near Earth Asteroid Rendezvous) mission