Search NASA⌕ Search

SEARCH · Search NASA

Results for “comets missions”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Deep Space 1 Mission and observation of Comet Borrelly

After DS1 1 completed its successful primary mission in 1999, NASA sent it on a risky and ambitious extended mission to conduct comet science. In September 2001, DSl executed a flawless encounter with comet Borrelly, yielding the best pictures and other scientific data ever collected at a comet, providing scientists with a tremendous advance in our understanding of these intriguing and important parts of the solar system.

image analysis image processing mission planning N↗
NASA NTRS2000

Hummingbird Comet Nucleus Analysis Mission

Hummingbird is a highly focused scientific mission, proposed to NASA s Discovery Program, designed to address the highest priority questions in cometary science-that of the chemical composition of the cometary nucleus. After rendezvous with the comet, Hummingbird would first methodically image and map the comet, then collect and analyze dust, ice and gases from the cometary atmosphere to enrich characterization of the comet and support landing site selection. Then, like its namesake, Hummingbird would carefully descend to a pre-selected surface site obtaining a high-resolution image, gather a surface material sample, acquire surface temperature and then immediately return to orbit for detailed chemical and elemental analyses followed by a high resolution post-sampling image of the site. Hummingbird s analytical laboratory contains instrumentation for a comprehensive molecular and elemental analysis of the cometary nucleus as well as an innovative surface sample acquisition device.

Kojiro, Daniel↗
NASA NTRS1979

Scientific need for a cometary mission

Known facts about comets are reviewed including their organic and inorganic content. Photographs are used to show the differences in the physical appearances of the three types of comets. Space missions will provide the opportunity to determine the sequence of events that led to their formation and that of the solar system; how volatiles arrived on earth; and the basis for the existence of life on earth; and the source of the outer planetary system.

Whipple, F. L.↗
NASA NTRS1974

Mission strategy for cometary exploration in the 1980's

A sequence of ballistic intercept missions to comets is proposed. The mission set is composed of a well-known group of periodic comets whose physical properties are dissimilar. In addition to full descriptions of the nominal mission profiles, earth-based sighting conditions and estimates of cometary ephemeris errors are presented for each target comet. The first mission of the sequence is a slow flyby (approximately 8 km/sec) of Encke's comet near its perihelion in 1980. Because of a near resonance in the orbital periods of Encke and the spacecraft, it is possible to retarget the spacecraft for a second Encke encounter in 1984. The second mission of the sequence also consists of two cometary encounters but in this case different comets are involved; Giacobini-Zinner in 1985 and Borrelly in 1987. The final mission of the sequence calls for a simultaneous launch of two spacecraft towards Halley's comet in 1985. One spacecraft is targeted fo a pre-perihelion intercept at a heliocentric distance of 1.37 AU.

Farquhar, R. W.↗
NASA NTRS1985

The selection of comets for future space missions

The criteria used to select a short period comet for possible future rendezvous space missions are stated and the selection process is outlined. For the time period 1900-2000, several candidate comets offer opportunities for spacecraft rendezvous. Two of the best candidates are periodic comets Kopff and Wild 2.

Yeomans, D. K.↗
NASA NTRS2001

An Overview of the Comet Nucleus TOUR Discovery Mission and a Description of Neutral Gas and Ion Measurements Planned

The CONTOUR (Comet Nucleus TOUR) Mission led by its Principal Investigator Professor Joseph Veverka of Cornell is presently under development at the Johns Hopkins Applied Physics Laboratory for launch in July of 2002 with a flyby of Comet Encke scheduled for November 3, 2003 at a solar distance of 1.07 au. A robust Whipple dust shield is designed to allow a close nucleus approach distance (less than 150 km). The 2nd nominal CONTOUR target is Comet Schwassmann-Wachmann 3, although the spacecraft can alternately be directed to a new comet if such an interesting target is discovered. CONTOUR contains 4 instruments: an imaging spectrometer (CRISP) developed at APL that will obtain both high resolution nucleus images through 8 filters and IR spectra (800 to 2550 nm) of the nucleus, a narrow field of view forward imager (CFI) to locate the target days before the encounter, a dust composition time of flight mass spectrometer (CIDA) provided by Dr. J. Kissel and von Hoemer & Sulger, GmbH, and a mass spectrometer (NGIMS) provided by Goddard Space Flight Center to measure neutral gas and ambient ions. Laboratory calibration of the NGIMS has now been completed. NGIMS also includes an in-flight calibration system that we plan to exercise before and after each comet encounter. We will provide an overview of the CONTOUR Mission and discuss more specifically the NGIMS measurement goals for this mission.

Mahaffy, Paul↗
NASA NTRS1981

A CCD tracker for closed-loop instrument pointing at Halley's comet

An optical tracker based on CCD technology has been developed for the closed-loop pointing of the narrow-angle imaging system of the proposed Halley's comet intercept mission at the comet nucleus. The target tracker, needed to assure the accurate pointing of science instruments as the nucleus rapidly passes the spacecraft, is a component of the pointing control system, which also includes a two-axis articulated instrument platform and high-resolution optical encoders to measure platform orientation relative to spacecraft structure. The device was designed on the basis of a CCD imaging array to calculate target centroid position based on the optical intensity of all pixels containing the image, and a processor to perform spacecraft attitude control, pointing control and target tracker control and data processing functions. The tracker has been configured to operate in both target acquisition and tracking modes. Preliminary simulation results and past experiments on similar trackers indicate that excellent tracking performance can be achieved, and a breadboard version of the tracker is currently being fabricated.

Stanton, R. H.↗
NASA NTRS1985

Comet nucleus gamma-ray spectrometer penetrator - An in situ nucleus composition experiment

An engineering design study of a comet nucleus penetrator system for in situ determinations of comet composition is presented. The system is designed for participation in the Comet Rendezvous/Asteroid Flyby mission to comet Kopff in 1996. The instrumentation payload of the penetrator system will include a passive gamma-ray spectrometer; a high frequency response accelerometer for measurements of the impact deceleration profile of the system as it penetrates to the nucleus of the comet; and several thermocouples mounted along the length of the penetrator to measure temperature and temperature gradients. The mechanical, electrical and thermal interfaces between the penetrator and the Mariner Mark II spacecraft are described. A series of line drawings is provided which illustrates the proposed configuration of the system.

Swenson, B. L.↗
NASA NTRS1986

Future planetary exploration

The past, present, and future of planetary exploration are reviewed. A histogram of U.S. space launches between 1957 and 1983 shows that the peak activity came in 1966. Launchings of vehicles for planetary exploration also peaked in 1966, but the decreasing rate since that time has been partially offset by increased payload sophistication. Missions discussed include: the Galileo mission to Jupiter, several missions to Halley's comet, and missions to Venus. Missions in the early stages of planning include a Venus Radar Mapper, a Mars Geoscience/Climatology Orbiter, an ESA mission (Kepler) to orbit Mars, and a NASA Comet Rendezvous and Asteroid Flyby mission.

Kivelson, M. G.↗
NASA NTRS1992

Current trajectory options for a comet nucleus sample return mission

A summary of the current trajectory options available for the ESA comet nucleus sample return mission, Rosetta, is presented. These options include direct trajectories, delta-V-EGA trajectories using a Titan IV/Centaur launch vehicle with upgraded solid rocket motors, a trajectory involving a gravity assist of the earth (VEGA) prior to comet rendezvous, and one involving an additional gravity assist of the earth (VEEGA). Other propulsion options proposed and discussed are solar electric propulsion/ballistic trajectory modes and nuclear electric propulsion trajectory modes. Tables of performance data for each of these trajectory options are given.

Sauer, Carl G., Jr.↗
NASA NTRS2000

Ion propulsion system design for the Comet Nucleus Sample Return mission

One of the first science missions to use solar electric propulsion (SEP) may be the Comet Nucleus Sample Return (CNSR) mission which is designed to return samples of volatiles and dust from the nucleus of a comet. The use of SEP for CNSR makes the mission affordable and scientifically more attractive because it enables the use of a smaller, lower cost launch vehicle and it significantly reduces the time required to return samples to the Earth.

CNSR↗
NASA NTRS1971

Guidance and navigation requirements for unmanned flyby and swingby missions to the outer planets. Volume 4: High thrust mission, part 2, phase C

The guidance and navigation requirements for a set of impulsive thrust missions involving one or more outer planets or comets. Specific missions considered include two Jupiter entry missions of 800 and 1200 day duration, two multiple swingby missions with the sequences Jupiter-Uranus-Neptune and Jupiter-Saturn-Pluto, and two comets rendezvous missions involving the short period comets P/Tempel 2 and P/Tuttle-Giacobini-Kresak. Results show the relative utility of onboard and Earth-based DSN navigation. The effects of parametric variations in navigation accuracy, measurement rate, and miscellaneous constraints are determined. The utility of a TV type onboard navigation sensor - sighting on planetary satellites and comets - is examined. Velocity corrections required for the nominal and parametrically varied cases are tabulated.

Source record↗
NASA NTRS1992

Comets - Groundbased observations of spacecraft mission candidates

Ground-based narrowband photometry results are presented for nine candidate comets for flyby and/or rendezvous missions. The comets include Churyumov-Gerasimenko, d'Arrest, Encke, Grigg-Skjellerup, Honda-Mrkos-Pajdusakova, Kopff, Tempel 1, Tempel 2, and Wild 2. On the basis of measured OH production rates and a model of the sublimation of water from the surface, limits are derived on the size of each cometary nucleus. A detailed analysis of the characteristics of these nine viable mission candidates can furnish the bases for the prioritization of targets of prospective missions.

Osip, David J.↗