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NASA NTRS1999

Asteroids and Comets Outreach Compilation

Contents include various different animations in the area of Asteroids and Comets. Titles of the short animated clips are: STARDUST Mission; Asteroid Castallia Impact Simulation; Castallia, Toutatis and the Earth; Simulation Asteroid Encounter with Earth; Nanorover Technology Task; Near Earth Asteroid Tracking; Champollian Anchor Tests; Early Views of Comets; Exploration of Small Bodies; Ulysses Resource Material from ESA; Ulysses Cometary Plasma Tail Animation; and various discussions on the Hale-Bopp Comet. Animation of the following are seen: the Stardust aerogel collector grid collecting cometary dust particles, comet and interstellar dust analyzer, Wiper-shield and dust flux monitor, a navigation camera, and the return of the sample to Earth; a comparison of the rotation of the Earth to the Castallia and Tautatis Asteroids; an animated land on Tautatis and the view of the motion of the sky from its surface; an Asteroid collision with the Earth; the USAF Station in Hawaii; close-up views of asteroids; automatic drilling of the Moon; exploding Cosmic Particles; and the dropping off of the plasma tail of a comet as it travels near the sun.

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NASA NTRS1997

STS-83 Postflight Presentation

The flight crew of the STS-83 mission, Cmdr James D. Halsell, Pilot Susan S. Still, Payload Cmdr. Janice E. Voss, Mission Specialists Donald Thomas and Michael Gernhardt, and Payload Specialists Roger Crouch and Greg Linteris, offer a video and still photo presentation of their journey. Included in the presentation are an introduction of the crew and a short briefing by Cmdr. Halsell, the launch and ascent narrated by Still, Spacelab Module narration by Voss, mission control narrated by Cmdr. Halsell, experiment narration by Thomas and Crouch. Also included are video views of the Baja Peninsula, Sinai Peninsula, pivot-point irrigation circles, Comet Hale-Bopp, and the cross-wind landing. The crew poses outside the shuttle for photos. Crew members discuss still photos taken during the mission, including shots of sunsets, the Grand Bahamas Island, Nile River, Baja Peninsula, Indis River of India, and Guadalupe Island.

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NASA NTRS1997

STS-82 Mission Highlight Presentation

The STS-82 is the second in a series of planned service missions to the Hubble Space Telescope (HST). The flight crew of STS-82, Cmdr. Kenneth D. Bowersox, Pilot Scott J. Horowitz, Mission specialists, Mark C. Lee, Steven A. Hawley, Gregory J. Harbaugh, Steven L. Smith, and Joseph R. Tanner can be seen performing pre-launch activities preparing for the night launch. The crew meets the press for pre-launch photos before being transported to the launch pad. Several views can be seen of the final inspection team on the O level and the crew being readied in the 'white room'. Launch activities such as the oxygen vent hood retraction, liftoff, SRB separation, and personnel activities in the Houston Integrated Mission Control room are viewed. Subsequent footage is provided of the crew's activities during the HST rendezvous and docking, Extravehicular Activities (EVA's) preparation and EVA numbers 1, 3 and 5. During the first EVA the earth can be seen clearly in a reflection off of HST's offshroud during its 60th orbit crossing the equator. The HST deployment and views of the Hale-Bopp comet are clearly seen before Discovery's reentry and landing. After reentry a beautiful view of Discovery moving at 10,400 mph can be seen looking east from Mission Control. The ususal twin sonic boom precedes Discovery's touchdown on runway 15 at Kennedy Space Center. This second HST service mission orbited Earth 150 times and traveled 1.4 million miles.

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NASA NTRS1997

STS-85 Day 08 Highlights

On this eighth day of the STS-85 mission, the flight crew, Cmdr. Curtis L. Brown, Jr., Pilot Kent V. Rominger, Payload Cmdr. N. Jan Davis (Ph.D.), Mission Specialists Robert L. Curbeam, Jr. and Stephen K. Robinson (Ph.D.), and Payload Specialist Bjarni V. Tryggvason entered the final portion of its flight. The new Mir 24 crew of Commander Anatoly Solovyev and Flight Engineer Pavel Vinogradov, who arrived on the station the same day Discovery was launched, bid farewell to Mir 23 Commander Vasily Tsibliev and Flight Engineer Alexander Lazutkin who are returning home after 185 days in space. The Soyuz vehicle carrying the Mir 23 crew home undocked from the station. Robinson again used the Southwest Ultraviolet Imaging System (SWUIS), a 7-inch imaging telescope that is pointed out of the orbiter's middeck hatch window, to observe the Hale-Bopp comet. Curbeam continued his work with the Bioreactor Demonstration System designed to perform cell biology experiments under controlled conditions. Tryggvason spent part of his time troubleshooting a computer hard drive system that supports the Microgravity Vibration Isolation Mount experiment.

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NASA NTRS1997

STS-85 Day 09 Highlights

On this ninth day of the STS-85 mission, the flight crew, Cmdr. Curtis L. Brown, Jr., Pilot Kent V. Rominger, Payload Cmdr. N. Jan Davis (Ph.D.), Mission Specialists Robert L. Curbeam, Jr. and Stephen K. Robinson (Ph.D.), and Payload Specialist Bjarni V. Tryggvason watch over the Manipulator Flight Demonstration (MFD) experiment while Japanese investigators again maneuvere the Small Fine Arm remotely from a control room near Mission Control. It is the final planned work with the arm during this mission. While MFD operations are ongoing, Robinson again uses the Southwest Ultraviolet Imaging System's ultraviolet imaging telescope to observe Comet Hale-Bopp and Curbeam continue his work with the Bioreactor Demonstration System designed to perform cell biology experiments under controlled conditions. Tryggvason spends his day supporting data gathering with the Microgravity Vibration Isolation Mount experiment. Before the crew's workday began, they discussed the mission's progress with reporters in the U.S. and Canada as part of the traditional crew news conference. Questions ranged from life in space for the first time space travelers to providing a report card on the more than 24 experiments being conducted throughout the mission.

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NASA NTRS1999

Operation of the University of Hawaii 2.2M Telescope on Mauna Kea

This paper presents a final report from March 1, 1997-February 28, 1999 on the Operation of the University of Hawaii 2.2M Telescope on Mauna Kea. The topics include: 1) Telescope and Instrumentation (Newsletter and Documentation, Scheduling Periods); and 2) Scientific Highlights (The Outer Solar System-Trans-Neptunian Objects and the Kuiper Belt, Comet Hale-Bopp, Near-Earth Asteroids, Asteroid Families, and Galileo Mission Support).

McLaren, Robert A.↗
NASA NTRS1999

Synthesis of Large Molecules in Cometary Ice Analogs: Physical Properties Related to Self-Assembly Processes

The combination of realistic laboratory simulations and infrared observations have revolutionized our understanding of interstellar dust and ice-the main component of comets. Since comets and carbonaceous micrometeorites may have been important sources of volatiles and carbon compounds on the early Earth, their organic composition may be related to the origin of life. Ices on grains in molecular clouds contain a variety of simple molecules. The D/H ratios of the comets Hale-Bopp and Hyakutake are consistent with a primarily interstellar ice mixture. Within the cloud and especially in the presolar nebula through the early solar system, these icy grains would have been photoprocessed by the ultraviolet producing more complex species such as hexamethylenetetramine, polyoxymethylenes, and simple keones. We reported at the 1999 Bioastronomy meeting laboratory simulations studied to identify the types of molecules which could have been generated in pre-cometary ices. Experiments were conducted by forming a realistic interstellar mixed-molecular ice (H2O, CH3OH, NH3 and CO) at approximately 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The gas mixture was typically 100:50:1:1, however when different ratios were used material with similar characteristics was still produced. The residue that remained after warming to room temperature was analyzed by HPLC, and by several mass spectrometric methods. This material contains a rich mixture of complex compounds with mass spectral profiles resembling those found in IDPs and meteorites. Surface tension measurements show that an amphiphilic component is also present. These species do not appear in various controls or in unphotolyzed samples. Residues from the simulations were also dispersed in aqueous media for microscopy. The organic material forms 10-40 gm diameter droplets that fluoresce at 300-450 nm under UV excitation. These droplets have a morphology and internal structure which appear strikingly similar to those produced by extracts of the Murchison meteorite. Together, these results suggest a link between organic material photochemically synthesized on the cold grains in dense, interstellar molecular clouds and compounds that may have contributed to the organic inventory of the primitive Earth. For example, the amphiphilic properties of such compounds permit self-assembly into the membranous boundary structures that required for the first forms of cellular life.

Dworkin, Jason P.↗
NASA NTRS1997

Reconsidering the Theological and Ethical Implications of Extraterrestrial Life

As we stand on the threshold of a new millennium, we also find ourselves at the brink of a new and exciting era in space exploration. In fact, this new era has already begun, with the successful landing and exploration of Mars by the Pathfinder mission in July 1997. Pathfinder represents an important scientific accomplishment for NASA because it demonstrated the agency's ability to successfully explore space at a relatively modest price. At the same time, Pathfinder revealed once again the genuine interest and fascination that people all over planet Earth have for space exploration. The Pathfinder mission is just one of several recent events-both scientific and cultural-that reveal this deep and almost unquenchable curiosity about space-and the possibility that there is life "out there." In August 1996, the public was captivated with NASA's announcement that a meteorite from Mars may contain evidence of early microscopic life. Shortly after the NASA announcement, media coverage of the discovery-and public discourse concerning the discovery-turned to an examination of the theological implications of evidence for extraterrestrial, albeit unintelligent, life. To a lesser extent, public reaction to the Hale-Bopp comet in the Spring of 1996 is also suggestive of many persons' deep passion to know more about space.

Randolph, Richard O.↗
NASA NTRS1998

Chemistry in cometary comae

Significant gas-phase chemistry occurs in the comae of bright comets, as is demonstrated here for the case of Comet Hale-Bopp. The abundance ratio of the two isomers, hydrogen cyanide and hydrogen isocyanide, is shown to vary with heliocentric distance in a way that is consistent with production of HNC by ion-molecule chemistry initiated by the photoionization of water. Likewise, the first maps of emission from HCO+ show an abundance and an extended distribution that are consistent with the same chemical model.

Non-NASA Center↗
NASA NTRS1998

Silicate Mineralogy of the Dust in the Inner Coma of Comet C/1995 01 (Hale-Bopp) Pre- and Post-Perihelion

We present 7.6 - 13.3 microns infrared (IR) spectrophotometry (R approx. = 180 - 350) of the 10 microns silicate emission from dust in the inner coma (i.e., within a diameter of 3in.) of comet C/1995 O1 (Hale-Bopp) at four temporal epochs from 1996 October through 1997 June during Hale-Bopp s approach to, arrival at, and recession from perihelion. The HIFOGS spectra at large heliocentric distances exhibit strong emission peaks from 9.9 - 10.1 microns and at 11.2 microns. The HIFOGS spectra of Hale-Bopp taken 1996 October 07 - 14 UT are identical in shape to the ISO SWS spectrum at 2.8 AU obtained on 1996 October 06 UT. Magnesium-rich olivine was unambiguously identified due to presence of the expected 11.2 microns peak along with the matching far-IR 18 microns, 23 microns, and 33 microns peaks in the ISO SWS spectrum. In contrast, to large heliocentric distances, we find that the silicate feature at small heliocentric distances (tau(sub lambda) less than or = 1.7 AU) exhibits strong peaks at 9.3 microns, 9.9 - 10.1 microns, and 11.2 microns, and weak at 10.5 microns and 11.8 microns. We will show that the dramatic increase of the 9.3 microns and 10.0 microns peaks close to perihelion leads to the hypothesis that there are two crystalline grain components with significantly different temperatures. The hotter mineral species (including olivines) radiate over a large range of heliocentric distances at detectable leve!s. The cooler mineral species (pyroxenes) radiate on the Wien side of the blackbody, too faint to detect in the mid-infrared spectra, until close to the sun when this species radiates on the Reyleigh-Jeans tail and becomes apparent. Decomposition of the observed silicate emission features into mineral components through comparison of the height and shape of the silicate feature ("Flux/cont") derived from the cometary spectra, to optical extinctions (Qext) derived from laboratory measurements of terrestrial silicate minerals and interplanetary dust particles (IDPs) is successful for a combination of warm grains (consisting of olivines, amorphous olivines, amorphous pyroxenes, and layer-lattice silicates) and cool grains (crystalline pyroxenes).

Wooden, Diane H.↗
NASA NTRS1999

Optical Studies of Active Comets

This grant was to support optical studies of comets close enough to the sun to be outgassing. The main focus of the observations was drawn to the two extraordinarily bright comets Hyakutake and Hale-Bopp, but other active comets were also studied in detail during the period of funding. Major findings under this grant include: (1) Combined optical and submillimeter observations of the comet/Centaur P/Schwassmann-Wachmann 1 were used to study the nature of mass loss from this object. (2) We modelled the rotation of cometary nuclei using time-resolved images of dust jets as the primary constraint. The fortuitous apparition of comet Hale-Bopp allowed us to see the full complexity of this. (3) We obtained broad-band optical images of several comets for which we subsequently attempted submillimeter observations, in order to test and update the cometary ephemerides. This step is essential to the success of submillimeter observations, which are taken by instruments with narrow fields of view and without benefit of optical confirmation of the pointing. (4) Broad-band continuum images of a set of weakly active comets and, apparently, inactive asteroids were obtained in BVRI using the University of Hawaii 2.2-m telescope. These images were taken in support of a program to test the paradigm that many near-Earth asteroids might be dead or dormant comets. We measured coma vs. nucleus colors in active comets (finding that coma particle scattering is different from, and cannot be simply related to, nucleus color). (5) We obtained spectroscopic observations of weakly active comets and other small bodies limits to outgassing from these bodies, aided by the high (40,000) spectral resolution of HIRES.

Jewitt, David↗
NASA NTRS1999

Comets after Hyakutake and Hale-Bopp

Being icy, cometary nuclei are the most easily modified bodies in the solar system - even modest heating is sufficient to induce significant weight loss. This sublimative loss and longterm storage far from the sun protect the nucleus against internal warming and ensure that cometary nuclei today contain the least processed material remaining from the early nebula - or perhaps from the natal cloud. The chemical compositions of ices, low temperature-refractory organics, and refractory minerals (and their physical states) provide sensitive probes of the origin and history of this material. The fortunate appearance of Hyakutake and Hale-Bopp has provided a wealth of information on these Oort cloud comets, obtained with a wide range of astronomical approaches. I will review certain key results for these comets, such as chemical abundances, isotopic abundance ratios, nuclear spin statistics, and nuclear vs extended production of "parent volatiles", and will illustrate how these test the origins of cometary material. A comparison with 1P/Halley--a third comet from the giant planet nebular region--will be discussed in the context of heterogeneity among these bodies.

Mumma, Michael J.↗
NASA NTRS1998

Optical Studies of Active Comets

This grant was to support optical studies of comets close enough to the sun to be outgassing. The main focus of the observations was drawn to the two extraordinarily bright comets Hyakutake and Hale-Bopp, but other active comets were also studied in detail during the period of funding. Major findings (all fully published) under this grant include: (1) Combined optical and submillimeter observations of the comet/Centaur P/Schwassmann-Wachmann 1 were used to study the nature of mass loss from this object. The submillimeter observations show directly that the optically prominent dust coma is ejected by the sublimation of carbon monoxide. Simultaneous optical-submillimeter observations allowed us to test earlier determinations of the dust mass loss rate. (2) We modelled the rotation of cometary nuclei using time-resolved images of dust jets as the primary constraint. (3) We obtained broad-band optical images of several comets for which we subsequently attempted submillimeter observations, in order to test and update the cometary ephemerides. (4) Broad-band continuum images of a set of weakly active comets and, apparently, inactive asteroids were obtained in BVRI using the University of Hawaii 2.2-m telescope. These images were taken in support of a program to test the paradigm that many near-Earth asteroids might be dead or dormant comets. We measured coma vs. nucleus colors in active comets (finding that coma particle scattering is different from, and cannot be simply related to, nucleus color). We obtained spectroscopic observations of weakly active comets and other small bodies using the HIRES spectrograph on the Keck 10-m telescope. These observation place sensitive limits to outgassing from these bodies, aided by the high (40,000) spectral resolution of HIRES.

Jewitt, David↗
NASA NTRS1999

Detection of CO and Ethane in Comet 21P/Giacobini-Zinner: Evidence for Variable Chemistry in the Outer Solar Nebula

Ethane and carbon monoxide were detected in a short-period comet of probable Kuiper belt origin. Ethane is substantially less abundant compared with Hyakutake and Hale-Bopp, two comets from the giant-planets region of the solar nebula, suggesting a heliocentric gradient in ethane in pre-cometary ices. It is argued that processing by X-rays from the young sun may be responsible.

Mumma, M. J.↗
NASA NTRS1999

The Selicate Material In Comets

Silicates in comets appear to be a mix of high-temperature crystalline enstatite and forsterite plus glassy or amorphous grains that formed at lower temperatures.

comets Hale-Bopp silicates infrared spectra↗
NASA NTRS1999

Administrative Report on Training Awards

During the tenure of this award, the recipient (David Harker) conducted areas of research which resulted in the award of a doctorate degree (August 1999) from the University of Wyoming. The primary science activity was investigation of silicate dust mineralogy in comets, particularly comet C/1995 O1 (Hale-Bopp). Determination of the dust mineralogy permits us to address an important astrophysical question of relevance to the origins and evolution of solar systems, "Do comets contain relic interstellar dust grains? Since, comets represent the frozen reservoirs of primitive proto-solar dust and ice, we can gain insight into the problem of understanding the formation of protoplanetesimals in the. early solar nebula. Mid-infrared spectrophotometry (7 - 14 micron, R approx. = 180 - 360) of Hale-Bopp was obtained with the NASA/Ames HIFOGS at four distinct epochs pre- and post- perihelion ion from 1996 October through 1997 June. These observations were conducted at the Wyoming Infrared Observatory and the NASA Infrared Telescope Facility, and were supported by funds from this training grant. The emission at mid-IR wavelengths in cometary comae arises from carbon grains, and small silicate grains which produce resonance features. Hale-Bopp had the strongest silicate feature observed from any comet to date. Theoretical calculations utilizing Mie Scattering Theory were employed to construct Synthetic cometary spectra to fit with the observed HIFOGS 10 microns spectral feature of Hale-Bopp. Our analysis suggests that the observed spectra can be modeled with the Hanner grain size distribution peaked at alpha((sub p) = 0.2 microns of fractal porous grains with porosity parameter D = 2.5. This model spectrum also fits photometry points in the 3 - 5 microns region. Comparison with the ISO SWS spectrum of Hale-Bopp obtained 1996 October reveals that the crystalline olivine grains must be at it temperature hotter than computed from Mie theory.

Woodward, Charles E.↗
NASA NTRS1999

NASA/University Joint Venture (JOVE) Program

Hale-Bopp observations at the NASA IRTF concluded in September 1997. For the post Hale-Bopp period, telescope time was awarded to study comet Giacobini-Zinner in October 1998 at the NASA IRTF. A total of 6 nights were awarded to our team to study the comet where 2 of those 6 nights were awarded to Magee-Sauer as the principal investigator. Other observing trips were awarded to study YSOs (October 1998) and Mars (spring 1999) were Magee-Sauer was a co-investigator. An observing run from July 4 -7 1999 included study of Mars and YSOS. Our group has started to use the NIRSPEC instrument on the Keck II telescope. In collaboration with the development team from UCLA, we obtained images of comet Lee in August 1999. Telescope proposals are submitted each semester for targeted comet observations when a comet is bright enough to observe.

Magee-Sauer, Karen P.↗