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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Comet nucleus and asteroid sample return missions

During the 1991-92 academic year, the Pennsylvania State University has developed three sample return missions: one to the nucleus of comet Wild 2, one to the asteroid Eros, and one to three asteroids located in the Main Belt. The primary objective of the comet nucleus sample return mission is to rendezvous with a short period comet and acquire a 10 kg sample for return to Earth. Upon rendezvous with the comet, a tethered coring and sampler drill will contact the surface and extract a two-meter core sample from the target site. Before the spacecraft returns to Earth, a monitoring penetrator containing scientific instruments will be deployed for gathering long-term data about the comet. A single asteroid sample return mission to the asteroid 433 Eros (chosen for proximity and launch opportunities) will extract a sample from the asteroid surface for return to Earth. To limit overall mission cost, most of the mission design uses current technologies, except the sampler drill design. The multiple asteroid sample return mission could best be characterized through its use of future technology including an optical communications system, a nuclear power reactor, and a low-thrust propulsion system. A low-thrust trajectory optimization code (QuickTop 2) obtained from the NASA LeRC helped in planning the size of major subsystem components, as well as the trajectory between targets.

Melton, Robert G.↗
NASA NTRS1973

Implications of current SEP mission performance data on planning exploration of comets and asteroids.

The most comprehensive performance data base currently available for SEP comet and asteroid rendezvous missions has been synthesized and reduced into forms allowing evaluation of primary mission planning parameters. These data are based on utilization of the Shuttle with a Centaur injection stage and a SEP system having a 3000-sec specific impulse. The analysis indicates that a SEP vehicle system designed at a power level of around 20 kW with a system operating life of three years, offers the capability for achieving rendezvous missions to almost all comet and asteroid targets expected to be of interest in the 1980s. This degree of mission selection flexibility is desirable for a comprehensive program of small body exploration.

Allen, L. C.↗
NASA NTRS2004

Wild2 approach maneuver strategy used for Stardust spacecraft (extended abstract)

Stardust, NASA's first dedicated sample return mission to a comet, successfully flew through the comet dust around Wold2 on January 2, 2004. The spacecraft flew within 236 km of the comet, meeting the mission requirement of 250+/- 50 km on flyby distance. Stardust collected dust particles and took several images of the comet while flying close to Wild2. The spacecraft will return to earth with the comet samples on January 15, 2006. To accomplish the above objective, a large Deep Space Maneuver (DSM#) was implemented during June 17 and 18, 2003 and a series of Trajectory Correction Maneuvers (TCMs) were also implemented during the 30 days prior to encounter. Both maneuver design and executions were influenced by number of factors including the small body ephemeris uncertainty, predictability of small forces arising from 3-axis attitude limit cycling and spacecraft slews. Maneuver design processes, including contingency plans, and maneuver performance characteristics, are discussed in this paper.

dust↗
NASA NTRS1984

Comet rendezvous

A Mariner Mark II spacecraft rendezvous mission with comet Kopff has been recommended by NASA's Solar System Exploration Committee, and is scheduled for a Shuttle launch in 1990. The spacecraft, which is scheduled to encounter the comet in 1994, will conduct a series of experiments including the study of the cometary nucleus, coma, and tail during perihelion passage; the determination of the nucleus and coma chemical/isotropic composition; the description of the nucleus's size, mass, rotation period, and pole occultation; distinctions of gas and dust hydrodynamics; and distinctions of solar wind interactions with the coma. The three-axis-stabilized spacecraft will be modular in design, and will incorporate a 490-Newton Insat engine, Viking Orbiter propulsion tanks, an Integrated Platform Pointing and Attitude Control Subsystem, and several scientific instruments. The spacecraft's Radio Frequency Subsystem will only use X-band telemetry with a downlink frequency of 8415 MHz, and an uplink frequency of 7161 MHz. The power sources in the present design include one radioisotope thermoelectric generator, three 3 Ah batteries, and a solar panel of approximately 7 sq m.

Draper, R. F.↗
NASA NTRS1995

Optimal lunar trajectories for a combined chemical-electric propulsion spacecraft

Spacecraft which utilize electric propulsion (EP) systems are capable of delivering a greater payload fraction compared to spacecraft using conventional chemical propulsion systems. Several researchers have investigated numerous applications of low-thrust EP including a manned Mars mission, scientific missions to the outer planets, and lunar missions. In contrast, the study of optimal combined high and low-thrust spacecraft trajectories has been limited. In response to the release of NASA's 1994 Announcement of Opportunity (AO) for Discovery class interplanetary exploration missions, a preliminary investigation of a lunar comet rendezvous mission using a solar electric propulsion (SEP) spacecraft was performed. The Discovery mission (eventually named Diana) was envisioned to be a two-phase scientific exploration mission: the first phase involved exploration of the moon and second phase involved rendezvous with a comet. The initial phase began with a chemical propulsion translunar injection and chemical insertion into a lunar orbit, followed by a low-thrust SEP transfer to a circular, polar, low-lunar orbit (LLO). After scientific data was collected at the moon, the SEP spacecraft performed a spiral lunar escape maneuver to begin the interplanetary leg of the mission. After escape from the Earth-moon system, the SEP spacecraft maneuvered in interplanetary space and performed a rendezvous with a short period comet. An initial study that demonstrated the feasibility of using EP for the lunar and comet orbit transfer was performed under the grant NAG3-1581. This final report is a continuation of the initial research efforts in support of the Discovery mission proposal that was submitted to NASA Headquarters in October 1994. Section 2 discusses the lunar orbit transfer phase of the Diana mission which involves both chemical and electric propulsion stages. Section 3 discusses the chemical lunar orbit insertion (LOI) burn optimization. Finally, section 4 presents the conclusions of this research effort.

Kluever, Craig A.↗
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 NTRS1982

Recent researches into solid bodies and magnetic fields in the solar system; Proceedings of the Topical Meeting and Symposium, Ottawa, Canada, May 16-June 2, 1982

Topics discussed include the magnetic history of the early solar system, impact processes in solid bodies (e.g., meteoroids and asteroids), and topics related to cometary missions. The section devoted to cometary missions lays particular stress on missions to Comet Halley; attention is given to such aspects of these missions as the investigation of hypervelocity impact on the Giotto Halley mission dust shield, the detection of energetic cometary and solar particles by the EPONA instrument on the Giotto mission, the dust hazard near Comet Halley in regard to the Vega project, and cometary ephemerides for spacecraft flyby missions.

Vette, J. I.↗
NASA NTRS1980

A ballistic mission to fly by Comet Halley

The paper describes the available options, ballistic trajectory opportunities, and a preliminary reference trajectory that were selected as a basis for spacecraft design studies and programmatic planning for a Halley ballistic intercept mission in 1986. The paper also presents trajectory, performance, and navigation data which support the preliminary selection.

Boain, R. J.↗
NASA NTRS1974

Mission design for a ballistic slow-flyby of comet Encke 1980

Preliminary mission analyses for a proposed 1980 slow flyby (7 to 9 km/sec) of comet Encke are presented. Among the topics covered are: science objectives, Encke's physical activity and ephemeris accuracy, trajectory and launch-window analysis, terminal guidance, and spacecraft concepts. The nominal mission plan calls for a near-perihelion intercept with two spacecraft using a single launch vehicle. Both spacecraft arrive at the same time, one passing within 500 km from Encke's nucleus on its sunward side, the other cutting through the tail region. By applying a small propulsive correction about three weeks after the encounter, it is possible to retarget both spacecraft for a second Encke intercept in 1984. The potential science return from the ballistic slow flyby is compared with other proposed mission modes for the 1980 Encke flyby mission including the widely advocated slow flyby using solar-electric propulsion. It is shown that the ballistic slow flyby is superior in every respect.

Farquhar, R. W.↗
NASA NTRS1988

A TEOM (tm) particulate monitor for comet dust, near Earth space, and planetary atmospheres

Scientific missions to comets, near earth space, and planetary atmospheres require particulate and mass accumulation instrumentation for both scientific and navigation purposes. The Rupprecht & Patashnick tapered element oscillating microbalance can accurately measure both mass flux and mass distribution of particulates over a wide range of particle sizes and loadings. Individual particles of milligram size down to a few picograms can be resolved and counted, and the accumulation of smaller particles or molecular deposition can be accurately measured using the sensors perfected and toughened under this contract. No other sensor has the dynamic range or sensitivity attained by these picogram direct mass measurement sensors. The purpose of this contract was to develop and implement reliable and repeatable manufacturing methods; build and test prototype sensors; and outline a quality control program. A dust 'thrower' was to be designed and built, and used to verify performance. Characterization and improvement of the optical motion detection system and drive feedback circuitry was to be undertaken, with emphasis on reliability, low noise, and low power consumption. All the goals of the contract were met or exceeded. An automated glass puller was built and used to make repeatable tapered elements. Materials and assembly methods were standardized, and controllers and calibrated fixtures were developed and used in all phases of preparing, coating and assembling the sensors. Quality control and reliability resulted from the use of calibrated manufacturing equipment with measurable working parameters. Thermal and vibration testing of completed prototypes showed low temperature sensitivity and high vibration tolerance. An electrostatic dust thrower was used in vacuum to throw particles from 2 x 10(exp 6) g to 7 x 10(exp -12) g in size. Using long averaging times, particles as small as 0.7 to 4 x 10(exp 11) g were weighted to resolutions in the 5 to 9 x 10(exp -13) g range. The drive circuit and optics systems were developed beyond what was anticipated in the contract, and are now virtually flight prototypes. There is already commercial interest in the developed capability of measuring picogram mass losses and gains. One area is contamination and outgassing research, both measuring picogram losses from samples and collecting products of outgassing.

Source record↗
NASA NTRS1994

Cometary Coma Chemical Composition (C4) Mission

Cometary exploration remains of great importance to virtually all of space science. Because comets are presumed to be remnants of the early solar nebula, they are expected to provide fundamental knowledge as to the origin and development of the solar system as well as to be key to understanding of the source of volatiles and even life itself in the inner solar system. Clearly the time for a detailed study of the composition of these apparent messages from the past has come. A comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, is now being studied as a candidate for the new Discovery program. This mission is a highly-focussed and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission. The C4 mission will concentrate on measurements that will produce an understanding of the composition and physical makeup of a cometary nucleus. The core science goals of the C4 mission are 1) to determine the chemical, elemental, and isotopic composition of a cometary nucleus and 2) to characterize the chemical and isotopic nature of its atmosphere. A related goal is to obtain temporal information about the development of the cometary coma as a function of time and orbital position. The four short-period comets -- Tempel 1, Tempel 2, Churyumov-Gerasimenko, and Wirtanen -which all appear to have acceptable dust production rates, were identified as candidate targets. Mission opportunities have been identified beginning as early as 1998. Tempel I with a launch in 1999, however, remains the baseline comet for studies of and planning the C4 mission. The C4 mission incorporates two science instruments and two engineering instruments in the payload to obtain the desired measurements. The science instruments include an advanced version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX with a sample collection system, an X-ray Fluorescence Spectrometer and a Pyrolysis-Gas Chromatograph, and a simplified version of the Neutral Gas and Ion Mass Spectrometer (NIGMS). Both of these instruments have substantial heritage as they are based on those developed for the CRAF Mission. The engineering instruments include a simplified Comet Dust Environmental Monitor (SCODEM) and a navigational Camera, NAVCAM. While neither of the instruments will be permitted to establish science requirements, it is anticipated that significant science return will be accomplished Radio science will also be included.

Carle, Glenn C.↗
NASA NTRS1992

Planetary missions using microspacecraft technology

Some of the planetary missions using microspacecraft of mass on the order of 10 kg which are presently being considered at JPL are discussed. The primary benefits offered by this type of spacecraft is the small and relatively inexpensive launch vehicles and short program development schedules. A mission presently considered by the Asteroid Investigation with Microspacecraft (AIM) study is described with special attention given to the spacecraft configuration; the AIM mission will launch three spacecraft from a single Pegasus vehicle, achieving separate flybys for three near-earth asteroids. Attention is also given to the salient features of the Mars Rover Sample Return mission, the Venus Atmospheric Sounder, and the Comet Nucleus Mission, for which the application of microspacecraft technology is considered.

Short, Kendra L.↗
NASA NTRS2014

A Coordinated Focused Ion Beam/Ultramicrotomy Technique for Serial Sectioning of Hayabusa Particles and Other Returned Samples

Recent sample return missions, such as NASA's Stardust mission to comet 81P/Wild 2 and JAXA's Hayabusa mission to asteroid 25143 Itokawa, have returned particulate samples (typically ~5-50 μm) that pose tremendous challenges to coordinated analysis using a variety of nano- and micro-beam techniques. The ability to glean maximal information from individual particles has become increasingly important and depends critically on how the samples are prepared for analysis. This also holds true for other extraterrestrial materials, including interplanetary dust particles, micrometeorites and lunar regolith grains. Traditionally, particulate samples have been prepared using microtomy techniques (e.g., [1]). However, for hard mineral particles ≳20 μm, microtome thin sections are compromised by severe chatter and sample loss. For these difficult samples, we have developed a hybrid technique that combines traditional ultramicrotomy with focused ion beam (FIB) techniques, allowing for the in situ investigation of grain surfaces and interiors. Using this method, we have increased the number of FIB-SEM prepared sections that can be recovered from a particle with dimensions on the order of tens of μms. These sections can be subsequently analyzed using a variety of electron beam techniques. Here, we demonstrate this sample preparation technique on individual lunar regolith grains in order to study their space-weathered surfaces. We plan to extend these efforts to analyses of individual Hayabusa samples.

Berger, E. L.↗
NASA NTRS1975

Early Mariner comet flyby

An inexpensive first mission to a faint short period comet utilizing the spare Mariner Venus/Mercury spacecraft is studied with regard to science rationale and instrumentation and engineering feasibility and design. The spare Mariner spacecraft, suitably modified, is shown to be compatible with science requirements of a first comet flyby. Important aspects of this early mission would be penetration of the comet's gaseous coma and the approach of the nucleus to within hundreds of km in order to obtain in situ measurements and imaging that will help to establish comet science models and determine the hazards of a comet environment to future comet missions.

Nock, K. T.↗