A Window to the UV Universe:

The Engineering and Science

Helmed by Dr. George Carruthers

Dr. Kent Wood (Praxis, Inc.; retired-Naval Research

Laboratory)

Dr. Hakeem Oluseyi (Florida Institute of Technology)

Nancy Leon (NASA JPL)

Facilitator: Dr. Emma Marcucci (STScI)

Science Briefing

February 8, 2018

Additional Resources

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http://nasawavelength.org/list/2041Dr. George Carruthers:

ASP’s Arthur B.C. Walker II Award

Tribute video from U.S. Naval Research Laboratory

Ultraviolet Experiments:

Ritter Ultraviolet Experiment

Make a UV Detector

Seeing the Invisible:

Afterschool Universe: Session 4

The Effects of Ultraviolet Light on Perception (includes It’s Ok to be Smart

video via PBS and How and Why Bees see in UV)

UV Beads and Variations:

ASP’s Supernova! Toolkit (Activity 2 and 3)

UV Sensitive Beads

Sun As A Star (Activity 3)

Sunprints

Fun fact:

Pantone’s 2018 Color of the Year is Ultra Violet

Dr. Carruthers Tribute video

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https://www.nrl.navy.mil/media/videos/carruthers

Reflections on

the Career of

Dr. George Carruthers

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Dr. Kent WoodPraxis, Inc.Retired fromNaval Research Laboratory

Introduction

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• After receiving his doctorate at the University of Illinois in 1964, Dr. George Carruthers spent most of his career at the Naval Research Laboratory (NRL) where he developed cameras, telescopes and spectrographs operating in the far ultraviolet, making discoveries in astronomy and aeronomy

• This presentation consists of personal recollections supplemented with contributions with people who worked more closely with Carruthers at NRL, particularly Dr. Kenneth Dymond (NRL), Dr. Robert McCoy( Geophysics Institute, University of Alaska), Dr. Edward Jenkins (Princeton), and Dr. Scott Budzien (NRL).

• Disclaimer: this presenter never worked directly on George Carruthers’ space payloads but we did work in the same corporate culture, namely NRL’s Space Science Division, for more than three decades. This provided many opportunities for contact and included interaction over many years in the course of preparing one mission, the Air Force ARGOS satellite, on which we both had experiments.

Carruthers’ Scientific Career at NRL

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• George Carruthers arrived at NRL when the Lab was developing methods for extending observations to wavelengths outside the visible, including major efforts in X-rays and Ultraviolet, as part of the space program in which NRL was then a pioneering institution.

• There were recognized incentives to develop improved far UV imaging instruments and spectrometers for space use. These could be flown on sounding rockets, launched at White Sands Missile Range. Payloads could could observe selected targets for a few minutes. There were also other opportunities for flight including unique possibilities provided by the Apollo program

• George developed his own payloads used to observe suitable targets, including the Earth, Solar System objects, and astronomical sources. He and his colleagues analyzed the data from these systems and published discoveries. His career runs the full range of the criteria for the Arthur B.C. Walker II award: space experiments, astronomy, other space-based measurements, and education.

• This talk will take a topical (rather than chronological) approach and will describe (1) his advances in instrumentation for far ultraviolet (FUV), (2) the astronomical discoveries, and (3) the discoveries in observation of Earth’s atmosphere.

Instrumentation for Far UV

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In developing complete systems for FUV, George utilized and made innovations in many components and techniques:

• optics, to focus FUV light, including attention surface reflective properties (experimenting with various materials and coatings such as MgF2 on Al or SiC

• gratings and filters, to separate different FUV wavelengths

• detector elements that could collect FUV absorb FUV photons, including photographic plates and photocathodes to convert FUV to electrons used to record images and spectra.

• data acquisition systems suitable for the various space-based platforms

• supporting equipment such as calibration apparatus and tools for data analysis

Experiments had to be financed. Some of George’s experiments were supported by NASA. Others were supported by the Navy under the DoDSpace Test Program. He also pursued applied uses of the equipment he produced.

Hardware Designs:

Apollo 16 Camera and GIMI

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Space Systems and Platforms

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Space systems developed by George Carruthers spanned a variety of modes of space access

• FUV sensor systems flown on sounding rockets

• Far UV Camera, placed on the Moon, with data retrieval by returning astronauts

• Space Shuttle, SPARTAN

• Imagers for selected spectral bands flown on satellites (ARGOS)

Consider now some of his discoveries

in astronomy and aeronomy

Discovery of Interstellar Molecular

Hydrogen (Warner Prize, 1973)

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• Hydrogen exists in molecular form (H2) in the interstellar medium.

• George had first detection of interstellar H2, in the absorption of a stellar spectrum, shown above. Multiple lines of the H2 molecule could be seen.

• For this he received the Warner Prize from the American Astronomical Society

Far UV Camera

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The camera was placed on Moon by Apollo 16 astronauts. Conducted first sky survey in any wavelength done from

a lunar-based telescope, and also first survey in Far UV.

Data were retrieved by astronauts and analyzed by Carruthers and colleagues. (Plates from data reduction phase now archived in Air & Space Museum.)

Camera shown on Moon with astronaut John Young in foreground (camera is behind Young’s right leg)

Far UV Sky: Survey Conducted

using Lunar Camera + Rockets

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• Observed selected sky regions, cataloging stars prominent in far UV. Many were massive hot stars.

• Most UV stars had broad thermal spectra also observable in visible. UV fluxes could be compared with spectral extrapolations from visible wavelengths.

• Publications continued into 1980s, such as Large Magellanic Cloud study

Comet Halley (1986)

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Few observers were prepared with instrumentation in FUV to be able to observe Halley’s comet when it made its 1986 passage near the Sun.

• George obtained both an

image and a spectrum in FUV from two rocket flights

Lyman Alpha Geocorona

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• Hydrogen is produced in the atmosphere by dissociation of water vapor and transported to high altitudes in the geocorona where it is excited by the solar wind.

• The excited hydrogen shows up in Far UV as a glow in Lyman alpha extending to many Earth diameters

• George Carruthers was able to image it with the Far UV camera on the Moon

Earth’s Ionosphere: Far UV Arcs

Photographed from the Moon

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• These arcs are an imaging diagnostic for an ionospheric effect called the Appleton anomaly. Its existence was inferred from study of the F2 layer as early as 1927, but this was the first image of it taken from outside the Earth’s magnetosphere

• The two arcs are mainly the 1304 Angstrom and 1356 Angstrom lines of oxygen, and reveal how the oxygen is transported by high altitude movements near the equator.

• This image was taken from the Moon using the Lunar Camera and is a cut-out from a larger FUV image (shown earlier) that includes many square degrees of adjacent sky

This famous, iconic image has inspired many later efforts to develop facilities to image the ionosphere from high orbit. It also shows the polar aurora in FUV.

Ionospheric Bubble (GIMI)

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This phenomenon was observed using Carruthers’ GIMI Experiment on ARGOS (1999) and relates to ionospheric instabilities

• GIMI (Global Imaging of the Ionosphere) was an imager for two bands in FUV built at NRL and flown under the USAF Space test program on the ARGOS satellite during 2000-2001.

• GIMI was George’s last satellite experiment before retirement.

• Also had first FUV image of a meteor during Leonids (1999)

Carruthers as Educator and his

Influence on Later Research

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• Colleagues — George worked for many years with Chet Opal (now deceased) and Harry Heckathorn (now retired) but also had many colleagues who worked with him for a few years, sometimes when starting their careers. (Bob McCoy is an example)

• He also had many younger students working in his lab and wanted to inspire young people to science careers. He did some of this with Howard University, including lecturing there.

• His work on imaging Earth’s ionosphere had considerable heritage in the form of other missions that pursued this same objective. These missions are still making the news. One (GOLD) has just been launched by NASA and will continue the tradition once it is activated.

Reminiscences: What Was it Like to

be Around George Carruthers when

he was at NRL?

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• George would bicycle to work from his home on Capitol Hill and would remain there for remarkably long hours. For George, 12 hours was a short day.

• He would spend time in his lab with his hardware. His lab was just across the hall from his office, so he tended to be in one small part of the building except when in the field or on travel. He knew where everything was in his lab (though nobody else could understand the system). He always maintained a box of transparencies on a table in his office that enabled him to produce a talk on any aspect of his work on short notice. George was deeply respected by NRL colleagues for his accomplishments, particularly by those who had been there for the longest time. He had many books in his office on his wide interests which included the Solar System, evolution, and climate change.

• One could easily visit him in his office. He was generous and helpful; also cordial to everyone while also being gently firm in defending his interests. He was particularly reliable on occasions when colleagues needed to join forces to achieve some programmatic objective. He was diligent and serious, but had a marvelous, dry, rich sense of humor that one could only appreciate through repeated conversations. He and I both stayed at work late, and our contacts often consisted of office conversations near the end of the work day. He would bike home, even in the dark; I would see him biking as I drove home in my car.

Conclusions

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• George Carruthers’ career pioneered Far UV measurements starting in the late 1960s and running to the early 2000s

– Innovations in instrumentation and techniques for Far UV

– Flights of a wide variety of systems, on many kinds of space platforms

– Discoveries in astronomy - interstellar H2, Far UV images of galaxies and nebulae, first Far UV survey

– Discoveries in aeronomy — Appleton anomaly observed from Moon, Lyman Alpha geocorona

– Commitment to education at all levels

A wonderful colleague, fondly remembered at NRL

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Dr. Hakeem Oluseyi (Florida Institute of Technology)

A Window to the UV Universe

NASA Space Place Website: Resources to Help You Reach Kids

Nancy Leon

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Reaching Young Learners

• NASA Space Place Website is targeted at upper elementary school age kids.

• Serves as NASA’s Science Mission Directorate’s kids page.

• Covers both space and Earth science topics.• Has a Spanish language companion site.• Clear and simple explanations of complex topics

make these subjects accessible to our target audience. https://spaceplace.nasa.gov/

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The Universe on Space Place(/menu/space/)

Setting the stage for talking about UV astronomy:the Universe area on the Space Place https://spaceplace.nasa.gov/menu/space/

A wide variety of topics include:• Stars• Planets (and exoplanets)• Galaxies• Supernovas• Interstellar space• Gravitational waves• And more!

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The Electromagnetic Spectrum on the Space Place

• Cosmic Colors viewer • (see astronomical objects

in different wavelengths) https://spaceplace.nasa.gov/cosmic-colors/

• Land of the Magic Windows (explanations of each part of the spectrum). https://spaceplace.nasa.gov/magic-windows/

• The Multiwavelength Universe poster – different telescopes see in different parts of the EM spectrum. https://spaceplace.nasa.gov/posters/

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UV Pages on the Space Place

Contributed by the GALEX mission:

• A Real Shooting Star (seeing Mira’s tail in UV) https://spaceplace.nasa.gov/mira/

• How Old Do I Look (red-shift) /whats-older/• Photon Pileup: (packages of light)

https://spaceplace.nasa.gov/photon-pileup/• GALEX downloadable posters (6 different posters

with UV-related content on the back) https://spaceplace.nasa.gov/posters/

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ASTC partnership

A Professional Development opportunity –

How to Use NASA Resources;

future funding resources available

• Seven webinars to be held in 2018, with these goals:o Increase knowledge of NASA Astrophysics-related conceptso Improve familiarity of NASA Astrophysics resources and ways to use themo Utilize real NASA datao Interact with NASA Subject Matter Experts

• To participate, join NASA’s Universe of Learning Community of Practice (CoP) through ASTC: http://community.astc.org/home.

• Webinars will be archived for later viewing, including this introductory video: https://vimeo.com/252961419

As a follow-on to this webinar series, there will be an opportunity to apply for $2,500 mini-fund resources to be competitively awarded to selected institutions, in order to implement or facilitate programming, produce exhibits, etc., using Universe of Learning resources.

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To ensure we meet the needs of the education community (you!), NASA’s UoL is committed to performing regular evaluations, to determine the effectiveness of Professional Learning opportunities like the Science Briefings.

If you prefer not to participate in the evaluation process, you can opt out by contactingKay Ferrari <kay.a.ferrari@jpl.nasa.gov>.

This product is based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Jet Propulsion Laboratory, Smithsonian Astrophysical Observatory, and Sonoma State University. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration.

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