Alan Stern

Last updated
Alan Stern
La NASA en la Embajada (34142640202).jpg
Stern in 2017
Born
Sol Alan Stern [1]

(1957-11-22) November 22, 1957 (age 63)
Nationality American
Alma mater University of Texas, Austin
University of Colorado, Boulder
Awards Nature's 10 (2015) [2]
Scientific career
Fields Astrophysics
Aerospace engineering
Planetary science
Institutions NASA
Southwest Research Institute

Sol Alan Stern (born November 22, 1957) is an American engineer and planetary scientist. He is the principal investigator of the New Horizons mission to Pluto and the Chief Scientist at Moon Express. [3] [4]

Contents

Stern has been involved in 24 suborbital, orbital, and planetary space missions, including eight for which he was the mission principal investigator. One of his projects was the Southwest Ultraviolet Imaging System, an instrument which flew on two space shuttle missions, STS-85 in 1997 and STS-93 in 1999. [5] [6]

Stern has also developed eight scientific instruments for planetary and near-space research missions and has been a guest observer on numerous NASA satellite observatories, including the International Ultraviolet Explorer, the Hubble Space Telescope, the International Infrared Observer and the Extreme Ultraviolet Observer. Stern was Executive Director of the Southwest Research Institute's Space Science and Engineering Division until becoming Associate Administrator of NASA's Science Mission Directorate in 2007. He resigned from that position after nearly a year. In early 2009 Stern's name was mentioned as a potential contender for the position of NASA administrator under President Obama's administration. [7] [8] Stern has stated, however, that he is not interested in the position at this time given his desire to spend time with his family. [9]

Life and career

Stern was born in New Orleans, Louisiana, the son of Joel and Leonard Stern. [1] He graduated from St. Mark's School of Texas in 1975. He then attended the University of Texas, Austin, where he received his bachelor's degrees in physics & astronomy and his master's degrees in aerospace engineering and planetary atmospheres. He earned a doctorate in astrophysics and planetary science from the University of Colorado, Boulder. [10] [5] [11]

From 1983 to 1991, Stern held positions at the University of Colorado in the Center for Space and Geoscience Policy, the office of the Vice President for Research, and the Center for Astrophysics and Space Astronomy. He received his doctorate in 1989. From 1991 to 1994 he was the leader of Southwest Research Institute's Astrophysical and Planetary Sciences group and was Chair of NASA's Outer Planets Science Working Group. From 1994 to 1998 he was the leader of the Geophysical, Astrophysical, and Planetary Science section in Southwest Research Institute's Space Sciences Department, and from 1998 to 2005 he was the Director of the Department of Space Studies at Southwest Research Institute. In 1995 he was selected to be a Space Shuttle mission specialist finalist and in 1996 he was a candidate Space Shuttle payload specialist but did not have the opportunity to fly on the Space Shuttle.

His research has focused on studies of our solar system's Kuiper belt and Oort cloud, comets, the satellites of the outer planets, Pluto, and the search for evidence of planetary systems around other stars. He has also worked on spacecraft rendezvous theory, terrestrial polar mesospheric clouds, galactic astrophysics, and studies of tenuous satellite atmospheres, including the atmosphere of the Moon.

In 2007, Stern was listed among Time magazine's 100 Most Influential People in The World. [12]

On August 27, 2008 Stern was elected to the Board of Directors of the Challenger Center for Space Science Education. [13]

In 2015, Stern was the recipient of Smithsonian Magazine's American Ingenuity Award in the Physical Sciences category. [14]

On October 7, 2016, Stern was inducted into the Colorado Space Hall of Fame. [15]

Inspiration for Pluto/Kuiper belt mission

Alan Stern and the New Horizons team celebrate after the spacecraft successfully completed its flyby of Pluto. Alan Stern and New Horizons Team Celebrate Pluto Flyby.jpg
Alan Stern and the New Horizons team celebrate after the spacecraft successfully completed its flyby of Pluto.

On June 14, 2007, in an address to the Smithsonian Institution for their "Exploring the Solar System Lecture Series", Stern commented on the New Horizons mission:

I recall going to JPL, the Jet Propulsion Lab, the summer of 1989 when I was in graduate school to take a summer course in planetary exploration at Caltech and this was the summer of the Voyager fly-by of Neptune and Triton (which has turned out to be rather a twin of Pluto). It was amazing to get to be a part of some first-time exploration like that! Within a matter of months, a small group of us had formed a team, an advocacy group, Why don't we get a mission together for Pluto?

Private sector experience

After completing a master's degree in aerospace engineering Stern spent seven years as an aerospace systems engineer, concentrating on spacecraft and payload systems at the NASA Johnson Space Center, Martin Marietta Aerospace, and the Laboratory for Atmospheric and Space Physics at the University of Colorado.

Stern is currently active as a consultant for private sector space efforts and has stated:

I am a fan of public-private partnerships and building bridges to new markets, I believe we are on the verge of a whole new era of space exploration and that the private sector can provide reliable cost effective services that can increase the value and leverage government space budgets. [16]

On June 18, 2008, Stern joined Odyssey Moon Limited (Isle of Man), a private industry effort, as a part-time Science Mission Director/consultant in their efforts to launch a robotic mission to the Earth's Moon by participating in the $30 Million Google Lunar X-Prize competition. [16]

In December 2008, Stern joined Blue Origin, a company that was founded by Amazon.com's Jeff Bezos as an independent representative for research and education Missions. [17] The company has stated that its objective is to develop a new vertical-take-off, vertical-landing vehicle known as New Shepard that is designed to take a small number of astronauts on a sub-orbital journey into space and reduce the cost of space transportation. The company is located in Kent, Washington and has flight tested some hardware.

In 2012, Stern co-founded Uwingu. [18]

Space science mission

Stern has extensive experience in instrument development, with a strong concentration in ultraviolet technologies. Stern is a principal investigator (PI) in NASA's UV sounding rocket program, and was the project scientist on a Shuttle-deployable SPARTAN astronomical satellite. [19] He was the PI of the advanced, miniaturized HIPPS Pluto breadboard camera/IR spectrometer/UV spectrometer payload for the NASA/Pluto-Kuiper Express mission, and he is the PI of the PERSI imager/spectrometer payload on NASA's New Horizons Pluto mission. Stern is also the PI of the ALI CE UV Spectrometer for the ESA/NASA Rosetta comet orbiter. He was a member of the New Millennium Deep Space 1 (DS1) mission science team, and is a Co-investigator on both the ESA SPICAM Mars UV spectrometer launched on Mars Express, and the Hubble Space Telescope Cosmic Origins Spectrograph (COS) installed in 2009. [20] He is the PI of the SWUIS ultraviolet imager, which has flown two Shuttle missions, and the SWUIS-A airborne astronomical facility. In this capacity, Stern has flown numerous WB-57 and F-18 airborne research astronomy missions. Stern and his colleague, Dr. Daniel Durda, have been flying on the modified F/A-18 Hornet with a sophisticated camera system called the Southwest Ultraviolet Imaging System (SWUIS). They use the camera to search for a hypothetical group of asteroids (Vulcanoids) between the orbit of Mercury and the Sun that are so elusive and hard to see that scientists are not sure they exist. [21] [22]

Although he is a qualified pilot, Stern and his colleague are not flying these missions but rather operating the instruments at up to 60,000 feet in the F/A-18's. With regards to mission preparation Stern has stated:[ citation needed ]

This is not pilot training. Its aircraft systems, egress training, communications. It's really how to live aboard the aircraft and help the pilot as required. The backseater has a checklist to do. I won't pretend that I am landing the plane at night. I have got stick time on the airplanes and I've been flying airplanes for 20 years, but let's not pretend I am the pilot here.

NASA experience

Stern has served on various NASA committees, including the Lunar Exploration Science Working Group (LExSWG) and the Discovery Program Science Working Group (DPSWG), the Solar System Exploration Subcommittee (SSES), the New Millennium Science Working Group (NMSWG), and the Sounding Rocket Working Group (SRWG). He was Chair of NASA's Outer Planets Science Working Group (OPSWG) from 1991 to 1994 and served as a panel member for the National Research Council's 2003-2013 Decadal Survey on planetary science. Stern is a member of the AAAS, the AAS, and the AGU. [6] [23]

NASA Associate Administrator

Stern was appointed NASA's Associate Administrator for the Science Mission Directorate, essentially NASA's top-ranking official for science, in April 2007. In this position Stern directed a US$4.4 billion organization with 93 separate flight missions and a program of over 3,000 research grants. During his tenure a record 10 major new flight projects were started and deep reforms of the research and also the education and public outreach programs were put in place. [16] [24] [25] Stern's style was characterised as "hard-charging" as he pursued a reform-minded agenda. [26] [27] He "made headlines for trying to keep agency missions on schedule and under budget" but faced "internal battles over funding". [25] [28] [29] He was credited with making "significant changes that have helped restore the importance of science in NASA's mission". [30] [31] [32] [33]

On March 26, 2008 it was announced that Stern had resigned his position the previous day, effective April 11. [26] [27] [34] [35] [36] He was replaced by Ed Weiler, who was to serve his second stint in the position. [37] [38] The resignation occurred on the same day that NASA Chief Michael D. Griffin overruled a decrease in funding for the Mars Exploration Rovers and Mars Odyssey missions that was intended to free up funds needed for the upcoming Mars Science Laboratory. [39] NASA officials would neither confirm nor deny a connection between the two events. [37] [40]

Stern left to avoid cutting healthy programs and basic research in order to cover cost overruns. [36] He believed that cost overruns in the Mars program should be accommodated from within the Mars program, and not taken from other NASA programs. Michael D. Griffin became upset with Stern for making major decisions without consulting him, while Stern was frustrated by Griffin's refusal to allow him to cut or delay politically sensitive projects. Griffin favored cutting "less popular parts" of the budget, including basic research, and Stern's refusal to do so led to his resignation. [36]

Casting doubt on the theory that Stern resigned due to conflict with former Administrator Griffin is his statement of March 25, 2009 at spacepolitics.com: [9]

One more fact: I did not quit over MER; in fact, I wasn't the person who tried to cut MER... I quit when my boss effectively told me he was taking over SMD to fund MSL no matter how much damage it did to the rest of SMD. Now, a year later, you can see that damage as canceled SMEX missions, long delayed New Frontiers and Discovery AOs, the effective end of MSR, and an outer planets flagship that is 3+ years later now than when I left, just 12 months ago. I am quite comfortable with my decision to leave, rather than eviscerate innocent SMD missions that should have proceeded apace...

On November 23, 2008, in an op-ed in The New York Times , Stern criticized NASA's inability to keep its spending under control. Stern said that, during his own time at NASA, "when I articulated this problem... and consistently curtailed cost increases, I found myself eventually admonished and then neutered by still higher ups, precipitating my resignation earlier this year." While complimenting current NASA Administrator Michael D. Griffin, Stern suggested that Griffin's decision to again bail out an over-budget mission was motivated by fear "that any move to cancel the Mars mission would be rebuffed by members of Congress protecting local jobs". [41]

Since leaving NASA, Stern has made constructive criticisms of the budgetary process and has advocated for revamping its public appeal. [42]

Planetary classification

Stern has become particularly involved in the debate surrounding the 2006 definition of planet by the IAU. After the IAU's decision was made he was quoted as saying "It's an awful definition; it's sloppy science and it would never pass peer review" and claimed that Earth, Mars, Jupiter and Neptune have not fully cleared their orbital zones and has stated in his capacity as PI of the New Horizons project that "The New Horizons project [...] will not recognize the IAU's planet definition resolution of August 24, 2006." [43] [44]

A 2000 paper by Stern and Levison proposed a system of planet classification that included both the concepts of hydrostatic equilibrium and clearing the neighbourhood used in the new definition, [45] with a proposed classification scheme labeling all sub-stellar objects in hydrostatic equilibrium as "planets" and subclassifying them into "überplanets" and "unterplanets" based on a mathematical analysis of the planet's ability to scatter other objects out of its orbit over a long period of time. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune were classified as neighborhood-clearing "überplanets" and Pluto was classified as an "unterplanet". One could take this classification system as planet and dwarf planet respectively, with the major difference of the IAU definition classifying the two as distinct categories of celestial bodies instead of two subsets of planets.

Satellite planets and belt planets

Some large satellites are of similar size or larger than the planet Mercury, e.g. Jupiter's Galilean moons and Titan. Stern has argued that location should not matter and only geophysical attributes should be taken into account in the definition of a planet, and proposes the term satellite planet for a planet-sized object orbiting another planet. Likewise planet-sized objects in the asteroid belt or Kuiper belt should also be planets according to Stern. [46] Others have used the neologism planemo (planetary-mass object) for the broad concept of "planet" advocated by Stern. [47]

Bibliography

Related Research Articles

Space exploration Discovery and exploration of outer space

Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration though is conducted both by unmanned robotic space probes and human spaceflight. Space exploration, like its classical form astronomy, is one of the main sources for space science.

Pluto Dwarf planet in the Kuiper belt of the Solar System

Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It was the first and the largest Kuiper belt object to be discovered. After Pluto was discovered in 1930 it was declared to be the ninth planet from the Sun. Beginning in the 1990s, its status as a planet was questioned following the discovery of several objects of similar size in the Kuiper belt, including the dwarf planet Eris. This led the International Astronomical Union (IAU) in 2006 to formally define the term "planet" — excluding Pluto and reclassifying it as a dwarf planet.

<i>New Horizons</i> First mission of the New Frontiers program; flyby reconnaissance of the dwarf planet Pluto and 486958 Arrokoth

New Horizons is an interplanetary space probe that was launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institute (SwRI), with a team led by S. Alan Stern, the spacecraft was launched in 2006 with the primary mission to perform a flyby study of the Pluto system in 2015, and a secondary mission to fly by and study one or more other Kuiper belt objects (KBOs) in the decade to follow, which became a mission to 486958 Arrokoth. It is the fifth space probe to achieve the escape velocity needed to leave the Solar System.

<i>Pluto Kuiper Express</i>

Pluto Kuiper Express was an interplanetary space probe that was proposed by Jet Propulsion Laboratory (JPL) scientists and engineers and under development by NASA. The spacecraft was intended to be launched to study Pluto and its moon Charon, along with one or more other Kuiper belt objects (KBOs). The proposal was the third of its kind, after the Pluto 350 and a proposal to send a Mariner Mark II spacecraft to Pluto.

Discovery Program

The Discovery Program is a series of Solar System exploration missions funded by the US National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. Each mission has a cost cap, at a lower level than a mission from NASA's New Frontiers or Flagship Programs. As a result, Discovery missions tend to be more focused on a specific scientific goal.

Steve Squyres Professor of Physical Sciences at Cornell University

Steven Weldon Squyres is the James A. Weeks Professor of Physical Sciences at Cornell University in Ithaca, New York. His research area is in planetary sciences, with a focus on large solid bodies in the Solar System such as the terrestrial planets and the moons of the Jovian planets. Squyres was the principal investigator of the Mars Exploration Rover Mission (MER). He is the recipient of the 2004 Carl Sagan Memorial Award and the 2009 Carl Sagan Medal for Excellence in Communication in Planetary Science. On October 28, 2010, Squyres received the 2010 Mines Medal for his achievements as a researcher and professor. He is the brother of Academy Award-nominated film editor Tim Squyres.

The Lunar and Planetary Institute (LPI) is a scientific research institute dedicated to study of the solar system, its formation, evolution, and current state. The Institute is part of the Universities Space Research Association (USRA) and is supported by the Science Mission Directorate of the National Aeronautics and Space Administration (NASA). Located at 3600 Bay Area Boulevard in Houston, Texas, the LPI maintains an extensive collection of lunar and planetary data, carries out education and public outreach programs, and offers meeting coordination and publishing services. The LPI sponsors and organizes several workshops and conferences throughout the year, including the Lunar and Planetary Science Conference (LPSC) held in March in the Houston area.

Dwarf planet Planetary-mass object

A dwarf planet is a planetary-mass object that does not dominate its region of space and is not a satellite. That is, it is in direct orbit of the Sun and is massive enough to be plastic – for its gravity to maintain it in a hydrostatically equilibrious shape – but has not cleared the neighborhood of its orbit of similar objects. The prototype dwarf planet is Pluto. The interest of dwarf planets to planetary geologists is that, being possibly differentiated and geologically active bodies, they may display planetary geology, an expectation borne out by the 2015 New Horizons mission to Pluto.

The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2016, has continued with eight further spacecraft missions. All of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but two have been flybys that have taken detailed observations without the probe landing or entering orbit. These probes make Jupiter the most visited of the Solar System's outer planets as all missions to the outer Solar System have used Jupiter flybys to reduce fuel requirements and travel time. On 5 July 2016, spacecraft Juno arrived and entered the planet's orbit—the second craft ever to do so. Sending a craft to Jupiter entails many technical difficulties, especially due to the probes' large fuel requirements and the effects of the planet's harsh radiation environment.

Space probe Unmanned space exploration vehicle

A space probe or a spaceprobe is a robotic spacecraft that does not orbit around the Earth, but instead, explores further into outer space. A spaceprobe may approach the Moon; travel through interplanetary space; flyby, orbit, or land on other planetary bodies; or enter interstellar space.

The Science Mission Directorate (SMD) of the National Aeronautics and Space Administration (NASA) engages the United States’ science community, sponsors scientific research, and develops and deploys satellites and probes in collaboration with NASA's partners around the world to answer fundamental questions requiring the view from and into space.

David Grinspoon

David H. Grinspoon is an American astrobiologist. He is Senior Scientist at the Planetary Science Institute and was the former inaugural Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology for 2012-2013.

Discovery and exploration of the Solar System

Discovery and exploration of the Solar System is observation, visitation, and increase in knowledge and understanding of Earth's "cosmic neighborhood". This includes the Sun, Earth and the Moon, the major planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, their satellites, as well as smaller bodies including comets, asteroids, and dust.

The Solar System — our Sun’s system of planets, moons, and smaller debris — is humankind’s cosmic backyard. Small by factors of millions compared to interstellar distances, the spaces between the planets are daunting, but technologically surmountable

Exploration of Pluto

The exploration of Pluto began with the arrival of the New Horizons probe in July 2015, though proposals for such a mission had been studied for many decades. There are no plans as yet for a follow-up mission, though follow-up concepts have been studied.

Planetary Science Decadal Survey

The Planetary Science Decadal Survey is a publication of the United States National Research Council produced for NASA and other United States Government Agencies such as the National Science Foundation. The document identifies key questions facing planetary science and outlines recommendations for space and ground-based exploration ten years into the future. Missions to gather data to answer these big questions are described and prioritized, where appropriate. Similar Decadal Surveys cover Astronomy and Astrophysics, Earth Science and Heliophysics.

Planetary science Science of astronomical objects apparently in orbit around one or more stellar objects within a few light years

Planetary science or, more rarely, planetology, is the scientific study of planets, moons, and planetary systems and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, originally growing from astronomy and earth science, but which now incorporates many disciplines, including planetary geology, cosmochemistry, atmospheric science, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology.

Flyby (spaceflight) Flight event at some distance from the object

A flyby is a spaceflight operation in which a spacecraft passes in close proximity to another body, usually a target of its space exploration mission and/or a source of a gravity assist to impel it towards another target. Spacecraft which are specifically designed for this purpose are known as flyby spacecraft, although the term has also been used in regard to asteroid flybys of Earth for example. Important parameters are the time and distance of closest approach.

Planetary Missions Program Office Division of NASA responsible for the Discovery, New Frontiers, and Solar System Exploration programs

The Planetary Missions Program Office is a division of NASA headquartered at the Marshall Space Flight Center, formed by the agency's Science Mission Directorate (SMD). Succeeding the Discovery and New Frontiers Program Office, it was established in 2014 to manage the Discovery and New Frontiers programs of low and medium-cost missions by third-party institutions, and the Solar System Exploration program of NASA-led missions that focus on prioritized planetary science objectives. The Discovery and New Frontiers programs were established in 1992 and 2001 respectively, and have launched fourteen primary missions together, along with two missions launched under the administration of the Planetary Missions Program Office. The Solar System Exploration Program was established alongside the office, with three missions planned for launch under the new program.

Hal A. Weaver

Harold Anthony "Hal" Weaver, Jr. is an American astronomer, known for his research into the composition of solar system bodies including comets and Kuiper belt objects.

References

  1. 1 2 Feature: How Alan Stern’s tenacity, drive, and command got a NASA spacecraft to Pluto | Science/AAAS | News
  2. "365 days: Nature's 10". Nature. 528 (7583): 459–467. 2015. Bibcode:2015Natur.528..459.. doi: 10.1038/528459a . ISSN   0028-0836. OCLC   1076418075. PMID   26701036.
  3. "Dr. Alan Stern named Chief Scientist for Moon Express". Solar System Exploration Research Virtual Institute. Retrieved January 9, 2019.
  4. "Moon Express Announces Dr. Alan Stern as Chief Scientist". Moon Express. Space Ref. July 20, 2011. Retrieved January 9, 2019.
  5. 1 2 "Associate Administrator for the Science Mission Directorate S. Alan Stern". April 2, 2007. Retrieved January 9, 2019.
  6. 1 2 "Dr. S. Alan Stern". Archived from the original on September 7, 2008. Retrieved April 9, 2009.
  7. Who Will Be the Next NASA Administrator?
  8. Brian Berger and Becky Iannotta (January 8, 2009). "Earth Scientist Emerges as Possible Replacement for NASA Chief" . Retrieved January 9, 2019.
  9. 1 2 Jeff Foust (March 25, 2009). "And then there were… none?". Space Politics. Retrieved January 9, 2019.
  10. Stern has earned the following college degrees:
    - BS PHY 1978, The University of Texas at Austin
    - BA AST 1981, The University of Texas at Austin
    - MS ASE 1980, The University of Texas at Austin
    - MS CE 1981, The University of Texas at Austin
    - PhD Astrophysics/Planetary Science 1989, University of Colorado Boulder
    (Alan Stern, Distinguished Alumni, Class of 2019)
    Quote:
    "Before receiving his doctorate from the University of Colorado in 1989, Stern completed twin master's degrees in aerospace engineering and atmospheric sciences at The University of Texas at Austin (1980 and 1981). His two undergraduate degrees are in physics and astronomy, also from UT Austin (1978 and 1981)."
  11. Stern, Sol Alan (1989). The evolution of comets and the detectability of extra-solar Oort Clouds. University of Colorado at Boulder. ProQuest   303694081.
  12. Jeffrey Kluger (May 3, 2007). "Alan Stern" . Retrieved January 9, 2019.Cite magazine requires |magazine= (help)
  13. "Challenger Center". Archived from the original on November 1, 2010. Retrieved June 11, 2020.
  14. "2015 American Ingenuity Award Winners". Smithsonian Magazine. Smithsonian. Retrieved January 9, 2019.
  15. Brevard Business News . "Foundation names honoree for Colorado Space Hall of Fame, event set for Oct. 7", vol. 34, no. 34, (Melbourne, Florida: 22 August 2016), p. 7.
  16. 1 2 3 space-services
  17. Doug Messier (December 8, 2008). "Alan Stern, Blue Origin Man" . Retrieved January 9, 2019.
  18. "Got a Name for a Crater on Mars? You Can Put It on Uwingu's List". NBC News. February 26, 2014. Retrieved January 9, 2019.
  19. "Missions - Spartan 201". NASA Science. NASA. Retrieved January 9, 2019.
  20. COS Website
  21. "SWUIS Story and Project Background" . Retrieved January 9, 2019.
  22. "Solar System Exploration" . Retrieved January 9, 2019.
  23. New Frontiers in the Solar System: An Integrated Exploration Strategy. Washington, D.C.: The National Academies Press. 2003. doi:10.17226/10432. ISBN   978-0-309-08495-6.
  24. http://www.lpi.usra.edu/opag/stern_nac_08.pdf
  25. 1 2 Eric Hand (August 3, 2008). "NASA science chief resigns". Nature . eISSN   1476-4687. ISSN   0028-0836.
  26. 1 2 Frank Morring, Jr. (March 26, 2008). "NASA science chief Alan Stern resigns". Aviation Week. Archived from the original on May 21, 2011. Retrieved March 26, 2008.
  27. 1 2 Brian Berger (March 26, 2008). "Weiler to replace Stern as NASA science chief". Space.com. Retrieved March 26, 2008.
  28. Warren E. Leary (January 1, 2008). "Wielding a Cost-Cutting Ax, and Often, at NASA". The New York Times. The New York Times Company. Retrieved January 9, 2019.
  29. Mark Matthews (March 26, 2008). "Alan Stern has left the (NASA) building". Orlando Sentinel . Archived from the original on April 3, 2008. Retrieved March 26, 2008.
  30. http://planetarynews.org/archive08/pen_v02_n09_080205.txt
  31. http://planetarynews.org/archive08/pen_v02_n01_080104.txt
  32. "Planetary Exploration Newsletter: NASA Science Mission Directorate Update - Alan Stern, Associate Administrator/SMD". August 22, 2007. Retrieved January 9, 2019.
  33. Mat Kaplan (March 26, 2008). "Planetary Society statement on Alan Stern's resignation from NASA". Planetary Society . Retrieved January 9, 2019.
  34. http://planetarynews.org/archive08/pen_v02_n19_080403.txt
  35. Warren E. Leary (March 27, 2008). "NASA's Science Chief Resigns". The New York Times . The New York Times Company . Retrieved January 9, 2019.
  36. 1 2 3 Andrew Lawler (April 4, 2008). "NASA's Stern Quits Over Mars Exploration Plans". Science . 320 (5872): 31. doi:10.1126/science.320.5872.31. PMID   18388264. S2CID   45036250.(subscription required)
  37. 1 2 Brian Berger (March 26, 2008). "An interview with NASA's next science chief". Space.com . Retrieved January 9, 2019.
  38. "Ed Weiler becomes NASA's science chief". United Press International. May 8, 2008. Retrieved January 9, 2019.
  39. Kate Tobin (March 24, 2008). "Mixed signals from NASA about fate of Mars rover". CNN . Retrieved January 9, 2019.
  40. Will Dunham (March 26, 2008). "NASA science chief resigns post suddenly". Reuters. Retrieved January 9, 2019.
  41. Alan Stern (November 23, 2008). "NASA's Black Hole Budgets". The New York Times. The New York Times Company. Retrieved January 9, 2019.
  42. S. Alan Stern (November 24, 2008). "The Space Review: Imagine reconnecting NASA" . Retrieved January 9, 2019.
  43. Paul Rincon (August 25, 2006). "Pluto vote 'hijacked' in revolt". BBC News . Retrieved January 9, 2019.
  44. Alan Stern (September 6, 2006). "Unabashedly Onward to the Ninth Planet". The PI's Perspective. New Horizons Web Site. Archived from the original on February 4, 2015. Retrieved January 9, 2019.
  45. Stern, S. Alan; Levison, Harold F. (2002). "Regarding the criteria for planethood and proposed planetary classification schemes" (PDF). Highlights of Astronomy. 12: 205–213, as presented at the XXIVth General Assembly of the IAU–2000 [Manchester, UK, August 7–18, 2000]. Bibcode:2002HiA....12..205S. doi:10.1017/S1539299600013289.
  46. Should Large Moons Be Called 'Satellite Planets'?
  47. G. Basri & E.M. Brown, 2006. Annual Review of Earth and Planetary Sciences, 34: 193–216.