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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

NASA mission planning for space nuclear power

An evaluation is conducted of those aspects of the Space Exploration Initiative which stand to gain from the use of nuclear powerplants. Low-power, less than 10 kW(e) missions in question encompass the Comet Rendezvous Asteroid Flyby, the Cassini mission to Saturn, the Mars Network mission, a solar probe, the Mars Rover Sample Return mission, the Rosetta comet nucleus sample return mission, and an outer planets orbiter/probe. Reactor power yielding 10-100 kW(e) can be used by advanced rovers and initial lunar and Martian outposts, as well as Jovian and Saturnian grand tours and sample-return missions.

Bennett, Gary L.↗
NASA NTRS1979

Report of the Comet Science Working Group

Scientific objectives and mission strategies for a flyby of Halley's comet and rendezvous with Tempel-2 are discussed. Instrumentation to be carried by both the rendezvous spacecraft and the coma probe payload are listed. Known characteristics of both comets are summarized.

Source record↗
NASA NTRS2001

Odyssey Comet Nucleus Orbiter: The Next Step in Cometary Exploration

Cometary nuclei are the most primitive bodies in the solar system, containing a cosmo-chemical record of the primordial solar nebula. Flyby missions to comets, such as those that encountered Comet Halley in 1986, provide a glimpse at this record. However, to study a cometary nucleus in detail requires a rendezvous mission, i.e., a nucleus orbiter. Only an orbiter provides the ability to map the entire nucleus surface at high resolution, to study the complex chemistry in the cometary coma and its variation with time, and to determine the mass and bulk density of the nucleus, key parameters in understanding how small bodies first formed in the solar nebula. A nucleus orbiter also provides the opportunity to sense the nucleus surface in preparation for more ambitious landing and sample return missions in the future. Additional information is contained in the original extended abstract.

Weissman, P. R.↗
NASA NTRS1987

Comet rendezvous - The next step

Features of a proposed NASA-West Germany Comet Rendezvous Asteroid Flyby mission (CRAF) are summarized. The spacecraft would carry an imaging system, visual and IR mapping spectrometers, an IR radiometer, an instrumented lander probe, ion mass, neutral-gas, secondary-ion mass, superthermal-ion and retarding potential ion mass spectrometers, etc. The spacecraft would fly alongside the nucleus, hover near it, and circle it. The earliest potential encounter would be with Comet Tempel 2 in October 1996, followed by a flyby of the asteroid 46 Hestia. The science goals of the mission are explored, mainly with reference to unanswered questions remaining after the Halley missions.

Neugebauer, Marcia↗
NASA NTRS1991

A ground test program to support condition monitoring of a spacecraft attitude control propulsion system

The Comet Rendezvous Asteroid Flyby (CRAF) mission involves seven years of flight from 0.6 to 4.57 Astronomical Units (AU), followed by about 915 days of maneuvering around a comet. Ground testing will characterize the very critical attitude control system thrusters' fuel consumption and performance for all anticipated fuel temperatures over thruster life. The ground test program characterization will support flight condition monitoring. A commercial software application hosted on a commercial microcomputer will control ground test operations and data acquisition using a newly designed thrust stand. The data acquisition and control system uses a graphics-based language and features a visual interface to integrate data acquisition and control.

Clark, Douglas J.↗
NASA NTRS2011

Navigation of the EPOXI Spacecraft to Comet Hartley 2

On November 4, 2010, the EPOXI spacecraft flew by the comet Hartley 2, marking the fourth time that a NASA spacecraft successfully captured high resolution images of a cometary nucleus. EPOXI is the extended mission of the Deep Impact mission, which delivered an impactor on comet Tempel-1 on July 4, 2005. EPOXI officially started in September 2007 and eventually took over 3 years of flight time and had 3 Earth gravity assists to achieve the proper encounter conditions. In the process, the mission was redesigned to accommodate a new comet as the target and changes in the trajectory to achieve better imaging conditions at encounter. Challenges in navigation of the spacecraft included precision targeting of several Earth flybys and the comet encounter, uncertainties in determining the ephemeris of the comet relative to the spacecraft, and the high accuracy trajectory knowledge needed to image the comet during the encounter. This paper presents an overview of the navigation process used for the mission.

Deep Impact (DI)↗
NASA NTRS1989

Rendezvous with Comet Kopff

Plans for the Comet Rendezvous Asteroid Flyby (CRAF) mission are discussed. The CRAF spacecraft and mission configurations are illustrated and the scientific studies planned for the mission are listed. The scientific benefits of the study of comets and asteroids are reviewed and the characteristics of Comet Kopff are outlined. In addition, the structure, propulsion, attitude and articulation control, radio frequency and antenna, power and pyro, command, and data storage subsystems are described.

Miller, Sylvia↗
NASA NTRS1987

Navigation of the Mariner Tempel 2 mission - Orbit phase and penetrator deployment

The navigation of the Mariner Mark II spacecraft about the comet Tempel 2 in the Comet Rendezvous Asteroid Flyby (CRAF) mission is described. This mission is the first of a series using the Mariner Mark II spacecraft planned for the 1990's and thereafter. The primary purpose of the mission is to orbit the nucleus of the periodic comet Tempel 2 and study it at close range. A secondary purpose is to fly by and observe one or two asteroids enroute to the comet. During the orbital phase of the mission, a penetrator will be deployed from the spacecraft to impact the surface of the comet and measure the composition and other properties of the nucleus. Navigation accuracies are given in this paper for spacecraft and penetrator trajectory prediction and control. The orbit determination performance in support of science observations while in orbit about the nucleus is also described.

Miller, James K.↗
NASA NTRS1986

Elemental analysis of a comet nucleus by passive gamma ray spectrometry from a penetrator

The Comet Rendezvous Asteroid Flyby (CRAF) spacecraft, to be launched in 1991, was designed to study the physical and chemical properties of cometary and asteroid bodies. It is proposed that these properties can be determined by utilizing a penetrator experiment delivery system aboard the CRAF, which would deliver a passive gamma ray spectrometer to the comet and determine the composition of subsurface materials. Results of calculations for a model comet (50 percent CI carbonaceous chrondrite, 50 percent ices) provide data on the expected gamma ray fluxes, the minimum detectable limits, and the detection uncertainties for 35 isotopes. These results confirm that this technique can determine the composition of both the rocky and ice components, and the rock-to-ice ratio in the nucleus. In addition, useful information regarding the formation of the solar system is provided.

Evans, L. G.↗
NASA NTRS1986

Affordable solar system exploration

The design features of the Comet Rendezvous Asteroid Flyby (CRAF) version of the Mariner Mark II spacecraft are described, together with the instruments to be carried aboard and the goals of the mission. To minimize the cost, computer-aided design, engineering, and manufacturing will be used, and, where possible, established technologies and off-the- shelf products will be incorporated. Planned for a launch in 1992, the CRAF will rendezvous with the Tempel 2 comet in 1996 and will stick with it through 1999, making studies of plasma in the comet's coma and the comet's dust, gas, and nucleus by means of its penetrator rocket which will pierce the nucleus.

Draper, Ronald F.↗
NASA NTRS1988

Outward to the Beginning: the CRAF and Cassini Missions of the Mariner Mark 2 Program

Two successive journeys will soon offer a perspective on the origin of the solar system and perhaps provide clues on the origin of life as well. The missions, the Comet Rendezvous Asteroid Flyby (CRAF) and Cassini (the Saturn orbiter/Titan probe), combine to form the first initiative of the Mariner Mark 2 program, a series of planetary missions whose common objective is to explore primitive bodies and the outer solar system, toward the ultimate goal of understanding the nature of our origins. Cassini and CRAF are exciting planetary missions. The objectives that they share, the region of the solar system in which comets, asteroids, and the Saturnian system have evolved and now reside, and the spacecraft that will carry both sets of experiments to their targets in the outer solar system are described.

Source record↗
NASA NTRS2006

The Stardust Discovery Mission - Returning Unique Samples of Early Solar System Organics

On January 2,2004, the STARDUST spacecraft made the closest ever flyby (236 km) of the nucleus of a comet - Comet Wild 2. During the flyby the spacecraft collected samples of dust from the coma of the comet. These samples were successfully returned to Earth on January 15,2006. After a six-month preliminary examination to establish the nature of the returned samples, they will be made available to the general scientific community for study. During my talk I will discuss the scientific goals of the STARDUST mission and provide a brief overview of the mission's design and flight. I will also discuss the recovery of the Stardust Sample Return Capsule (SRC), with an emphasis on those aspects of the recovery important for minimizing the degree of contamination (particularly organic contamination) of the samples. Finally, the first samples are only just now being distributed for preliminary examination, but I hope to be able to talk about some of the preliminary findings from the returned comet samples.

Sandford, Scott↗
NASA NTRS2006

Sample Return from the Stardust Mission

On January 2,2004, the STARDUST spacecraft made a close flyby (236 km) of the nucleus of a comet - Comet Wild 2. During the flyby the spacecraft collected samples of dust from the coma of the comet. These samples were successfully returned to Earth on January 15,2006. After a six month preliminary examination to establish the nature of the returned samples, they will be made available to the general scientific community for study. STARDUST is one of the missions carried out under NASA's Discovery Mission Program. During my talk I will present a brief overview of the scientific goals of the STARDUST mission and describe the mission's design and flight. I will also discuss the reentry and recovery of the Stardust Sample Return Capsule (SRC) in Utah, with an emphasis on those aspects of the recovery important for minimizing the degree of contamination (particularly organic contamination) of the samples. Finally, I will discuss some of the results coming out of the preliminary examination of the returned samples, with an emphasis on the nature of organic materials found in the samples.

Source record↗
NASA NTRS1994

Carbon in Comet Halley dust particles

Comets are small bodies of the solar system containing primarily a mixture of frozen gases and carbonaceous and mineral grains. They are likely to preserve volatile mineral from cold regions of the protosolar nebula and remnants of interstellar dust and gas. More than 2500 mass spectra of cometary grains with masses in the range 5 x 10 exp -17 to 5 x 10 exp -12 g were measured in situ by PUMA1 and PUMA2 mass spectrometers on board the VEGA spacecraft during flyby missions to Comet Halley. In this paper, we discuss different organic and inorganic C-containing components discovered so far in Comet Halley dust particles, the nature and abundance of which provide information about possible astrophysical sources of C and constrain models of interstellar grains.

Fomenkova, M. N.↗
NASA NTRS1992

Production rates for comet P/Temple 2 from long slit CCD spectroscopy

Since comet P/Temple-2 is one of the potential targets for the CRAF (Comet Rendezvous Asteroid Flyby) mission, we obtained long slit spectroscopic data with our CCD spectrograph during its 1988 apparition. As the same spectrograph was extensively used for observations of P/Halley, this allowed a direct spectroscopic comparison between the two objects. Furthermore we could choose a P/Halley spectrum which was taken at a heliocentric distance very close to that of P/Temple-2. Finally, we could adjust the integration windows along the slit to compensate for the different geocentric distances, so that roughly the same projected distance of the comets' comae was observed. The parameters for our observations are given.

Fink, Uwe↗
NASA NTRS1982

Cometary ephemerides for spacecraft flyby missions

The determination of cometary ephemerides is considered with reference to proposed missions to Comet Halley. It is noted that the ability of spacecraft without onboard navigation capability to fly close to target comets is limited chiefly by the comet's ephemeris uncertainty. The situation is complicated by nongravitational forces acting on a comet's nucleus and the paucity of observers currently making astrometric observations of comets. The nongravitational forces affecting Comet Halley are consistent with the rocket effect of an outgassing water ice nucleus; the nucleus is apparently rotating in a direct sense about a stable spin axis. It is emphasized that accurate Comet Halley ephemerides for close spacecraft flybys will require continued efforts to refine the existing nongravitational force model. In addition, the flyby mission to Comet Halley will require a well-organized network of astrometric observers. For this purpose, an Astrometry Network is being set up within NASA's International Halley Watch program.

Yeomans, D. K.↗
NASA NTRS1987

Application of solar electric propulsion to future planetary missions

Application of solar electric propulsion (SEP) to several near term planetary missions has been investigated and is described in this paper. The missions under consideration include a comet rendezvous-asteroid flyby mission (CRAF), an orbiter mission to Saturn (CASSINI) and a comet nucleus sample return mission (CNSR). Advances in both thruster and solar array technology indicate that these missions could benefit by use of a moderate size solar electric propulsion system. The trajectory scenarios considered in this paper include a solar electric earth gravity assist (SEEGA) mode for all three missions and a SEP rendezvous mode for both the CRAF and CNSR missions. In addition an all SEP propulsion mode and a hybrid SEP-chemical propulsion mode is described for the CNSR mission.

Sauer, Carl G., Jr.↗
NASA NTRS1994

Cometary Matter Analyser (COMA/CRAF)

This project was part of an international program under which the chemical composition of cometary dust particles was to be measured 'in situ' during a rendezvous and flyby mission of a Mariner Mark 2 space probe and a comet (depending on the time of launch). Two necessary tasks, preliminary hardware development and interface definition, have been completed within the projects submitted for approval. As a result a model close to the flight configuration has been created, which was to be made available to the flight hardware contractor and his purposes. The Comet Rendezvous and Asteroid Flyby (CRAF) mission was abandoned after joint resolution adopted by NASA and the Federal Ministry for Research and Technology in 1992. Since an instrument like CoMA is an important contribution both to future cometary rendezvous missions, such as ROSETTA, as well as for accompanying laboratory activities, this project was terminated in a 'qualified conclusion'. In the process, components suitable for the laboratory developed from the preliminary units were produced and put into operation.

COMETARY MATTER↗