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All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Interplanetary Transit Simulations Using the International Space Station

We evaluated the space life sciences utility of the International Space Station (ISS) to simulate the outbound transit portion of missions to Mars and Near Earth Asteroids (NEA) to investigate biomedical and psychological aspects of such transits, to develop and test space operation procedures compatible with communication delays and outages, and to demonstrate and validate technologies and countermeasures. Two major categories of space life sciences activities can capitalize on ISS capabilities. The first includes studies that require ISS (or a comparable facility), typically for access to prolonged weightlessness. The second includes studies that do not strictly require ISS but can exploit it to maximize their scientific return more efficiently and productively than in ground-based simulations. For these studies, ISS offers a high fidelity analog for fundamental factors on future missions, such as crew composition, mission control personnel, operational tasks and workload, real-world risk, and isolation, and can mimic the effects of distance and limited accessibility. In addition to conducting Mars- and NEA-transit simulations on 6-month ISS increments, extending the current ISS increment duration from 6 months to 9 or even 12 months will provide opportunities for enhanced and focused research relevant to long duration Mars and NEA missions. Increasing the crew duration may pose little additional risk to crewmembers beyond that currently accepted on 6-month increments, but additional medical monitoring capabilities will be required beyond those currently used for ISS operations. Finally, while presenting major logistical challenges, such a simulation followed by a post-landing simulation of Mars exploration could provide quantitative evidence of capabilities in an actual mission. Thus, the use of ISS to simulate aspects of Mars and NEA missions seems practical. If it were to be implemented without major disruption of on-going ISS activities, then planning should begin soon, in close consultation with all international partners.

Charles, John B.↗
NASA NTRS2007

The Mars Reconnaissance Orbiter Mission: From Launch to the Primary Science Orbit

The Mars Reconnaissance Orbiter (MRO) was launched from Cape Canaveral Air Force Station, Florida, USA, aboard an Atlas V-401 launch vehicle on August 12, 2005. The MRO spacecraft carries a very sophisticated scientific payload. Its primary science mission is to to provide global, regional survey, and targeted observations from a low altitude orbit for one Martian year (687 Earth days). After a seven month interplanetary transit, the spacecraft fired its six main engines and established a highly elliptical capture orbit at Mars. During the post-MOI early check-out period, four instruments acquired engineering-quality data. This was followed by five months of aerobraking operations. After aerobraking was terminated, a series of propulsive maneuvers were used to establish the desired low altitude science orbit. As the spacecraft is readied for its primary science mission, spacecraft and instrument checkout and deployment activities have continued.

orbiters↗
NASA NTRS1972

Performance of recoverable single and multiple Space Tugs for missions beyond earth escape.

A recoverable Space Tug launched by the Space Shuttle can provide the required post-orbital propulsion needed for placement of unmanned satellites. The Space Tug will also be used to launch interplanetary spacecraft from low earth orbit. This study summarizes the performance of single and multiple Space Tugs (in tandem) for launching spacecraft beyond earth escape. Trajectories are developed that allow recovery of the Tugs whenever practical. The effects of important Tug and trajectory parameters on performance are presented. It is concluded that a single Tug can inject spacecraft to Mars or Venus and still be recovered. The use of several Tugs in tandem can provide a significant increase in capability over the use of a single Tug. The more difficult missions involve a mix of recovered and expended Tugs.

Zimmerman, A. V.↗
NASA NTRS1975

Tracking and data system support for the Pioneer project. Volume 2: Pioneer 11 prelaunch planning through second trajectory correction, to 1 May 1973

The tracking and data system support of the planning, testing, launch, near-earth, and deep space phases of the Pioneer 11 Jupiter Mission are described, including critical phases of spacecraft flight and guidance. Scientific instruments aboard the spacecraft registered information relative to interplanetary particles and fields. Knowledge of the celestial mechanics of the solar system was improved through radiometric data gathering. Network performance, details of network support activity, and special support activities are discussed.

Barton, W. R.↗
NASA NTRS1981

CCD sensors for interplanetary spacecraft navigation and pointing control

The applications of practical optical image sensing CCDs to interplanetary spacecraft precision science payload delivery are discussed. The increasing demand for precision and flexibility in spacecraft for proposed new missions is forcing a transition to autonomous onboard navigation and pointing control. Onboard processing of video data is a crucial element in this transition and is made possible by CCD imagers and microprocessors. The pending Halley's comet close flyby is used as an example to examine details of the sensor design and the data processing which will meet the requirements. Target body centerfinding for optical navigation, target body tracking signal processing, and CCD sensor heads are examined, and flow charts and block diagrams are given for each.

Eisenman, A. R.↗
NASA NTRS2011

Estimation and Modeling of Enceladus Plume Density Using Attitude Control Data Collected by the Cassini Spacecraft During Low-Altitude Enceladus Flybys

The Cassini spacecraft was launched on 15 October 1997. After an interplanetary cruise of almost seven years, it arrived at Saturn on June 30, 2004. Major science objectives of the Cassini mission include investigations of the configuration and dynamics of Saturn's magnetosphere, the structure and composition of the rings, the characterization of several of Saturn's icy satellites, and Titan's atmosphere constituent abundance

Enceladus↗
NASA NTRS1965

Report from Mars - Mariner IV, 1964-1965

The successful mission of Mariner IV is a most gratifying conclusion to the first generation of lunar and planetary exploration, which has been based on lightweight automatic unmanned spacecraft in constant communication with Earth, designed for lunar impact or planetary encounter. The flight of this first Mars probe is noteworthy not only for the outstanding quantity and quality of scientific data but also as the verification of large and useful advances in a number of technological areas. The Mariner Mars Project of 1964-1965 was conducted for the National Aeronautics and Space Administration by the Jet Propulsion Laboratory; it was made possible by the valued assistance and support of many government agencies, scientific institutions, and industrial concerns. Among these are NASA's Lewis Research Center (Launch Vehicle Systems Manager) and their prime contractors, Lockheed Missiles and Space Corporation and General Dynamics/Convair; Goddard Space Flight Center (Launch Operations) and other agencies at Cape Kennedy; the agencies of the Australian, South African, and Spanish governments which operate overseas tracking stations; many hundreds of American industrial contractors and vendors; and a number of scientists in various fields of endeavor. The Project was established in late 1962 with the objective of conducting scientific observations near the planet Mars and returning the data to Earth for study and analysis; secondary objectives were to develop and study the equipment and techniques involved and to make certain scientific measurements of the interplanetary environment on the way to Mars. Successful accomplishment of these objectives under the severe constraints which were a part of the mission is a tribute to every single individual who shared in the preparation and execution of the Mariner Mars Project.

MARINER IV SPACE PROBE↗
NASA NTRS1991

Interplanetary crew exposure estimates for the August 1972 and October 1989 solar particle events

Detailed exposure estimates for the bone marrow, ocular lens, and skin of astronauts on manned missions beyond the earth's magnetosphere have been made for the large solar particle events (SPE) of August 1972 and October 1989. The estimates were made using the coupled neutron-proton space radiation transport computer code BRYNTRN and the CAM model for the human body. It is found that at least 10 g/sq cm aluminum shielding is needed to keep estimated dose equivalent values below current space radiation exposure guidelines recommended for LEO missions. Space suits currently being designed will not provide adequate crew protection and may not even ensure crew survival in the event of exposure to a large SPE during extravehicular activity.

Townsend, Lawrence W.↗
NASA NTRS1995

Long term microparticle impact fluxes on LDEF determined from optical survey of Interplanetary Dust Experiment (IDE) sensors

Many of the IDE metal-oxide-silicon (MOS) capacitor-discharge impact sensors remained active during the entire Long Duration Exposure Facility (LDEF) mission. An optical survey of impact sites on the active surfaces of these sensors has been extended to include all sensors from the low-flux sides of LDEF (i.e. the west or trailing side, the earth end, and the space end) and 5-7 active sensors from each LDEF's high-flux sides (i.e. the east or leading side, the south side, and the north side). This survey was facilitated by the presence of a relatively large (greater than 50 micron diameter) optical signature associated with each impact site on the active sensor surfaces. Of the approximately 4700 impacts in the optical survey data set, 84% were from particles in the 0.5 to 3 micron size range. An estimate of the total number of hypervelocity impacts on LDEF from particles greater than 0.5 micron diameter yields a value of approximately 7 x 10(exp 6). Impact feature dimensions for several dozen large craters on MOS sensors and germanium witness plates are also presented. Impact fluxes calculated from the IDE survey data closely matched surveys of similar size impacts (greater than or equal to 3 micron diameter craters in Al, or marginal penetrations of a 2.4 micron thick Al foil) by other LDEF investigators. Since the first year IDE data were electronically recorded, the flux data could be divided into three long term time periods: the first year, the entire 5.8 year mission, and the intervening 4.8 years (by difference). The IDE data show that there was an order of magnitude decrease in the long term microparticle impact flux on the trailing side of LDEF, from 1.01 to 0.098 x 10(exp -4) m(exp 2)/s, from the first year in orbit compared to years 2-6. The long term flux on the leading edge showed an increase from 8.6 to 11.2 x 10(exp -4) m(exp -2)/s over this same time period. (Short term flux increases up to 10,000 times the background rate were recorded on the leading side during LDEF's first year in orbit.) The overall east/west ratio was 44, but during LDEF's first year in orbit the ratio was 8.5, and during years 2-6 the ratio was 114. Long term microparticle impact fluxes on the space end decreased from 1.12 to 0.55 x 10(exp -4) m(exp -2)/s from the first year in orbit compared to years 2-6. The earth end showed the opposite trend with an increase from 0.16 to 0.38 x 10(exp -4) m(exp -2)/s. Fluxes on rows 6 and 12 decreased from 6.1 to 3.4 and 6.7 to 3.7 x 10(exp -4) m(exp -2)/s, respectively, over the same time periods. This resulted in space/earth microparticle impact flux ratios of 7.1 during the first year and 1.5 during years 2-6, while the south/north, space/north and space/south ratios remained constant at 1.1, 0.16 and 0.17, respectively, during the entire mission. This information indicates the possible identification of long term changes in discrete microparticle orbital debris component contributions to the total impact flux experienced by LDEF. A dramatic decrease in the debris population capable of striking the trailing side was detected that could possibly be attributed to the hiatus of western launch activity experienced from 1986-1989. A significant increase in the debris population that preferentially struck the leading side was also observed and could possibly be attributed to a single breakup event that occurred in September of 1986. A substantial increase in the microparticle debris population that struck the earth end of LDEF, but not the space end, was also detected and could possibly be the result of a single breakup event at low altitude. These results point to the importance of including discrete orbital debris component contribution changes in flux models in order to achieve accurate predictions of the microparticle environment that a particular spacecraft will experience in earth orbit. The only reliable, verified empirical measurements of these changes are reported in this paper. Further time-resolved in-situ measurements of these debris populations are needed to accurately assess model predictions and mitigation practices.

Simon, C. G.↗
NASA NTRS2010

Interplanetary Transit Simulations Using the International Space Station

It has been suggested that the International Space Station (ISS) be utilized to simulate the transit portion of long-duration missions to Mars and near-Earth asteroids (NEA). The ISS offers a unique environment for such simulations, providing researchers with a high-fidelity platform to study, enhance, and validate technologies and countermeasures for these long-duration missions. From a space life sciences perspective, two major categories of human research activities have been identified that will harness the various capabilities of the ISS during the proposed simulations. The first category includes studies that require the use of the ISS, typically because of the need for prolonged weightlessness. The ISS is currently the only available platform capable of providing researchers with access to a weightless environment over an extended duration. In addition, the ISS offers high fidelity for other fundamental space environmental factors, such as isolation, distance, and accessibility. The second category includes studies that do not require use of the ISS in the strictest sense, but can exploit its use to maximize their scientific return more efficiently and productively than in ground-based simulations. In addition to conducting Mars and NEA simulations on the ISS, increasing the current increment duration on the ISS from 6 months to a longer duration will provide opportunities for enhanced and focused research relevant to long-duration Mars and NEA missions. Although it is currently believed that increasing the ISS crew increment duration to 9 or even 12 months will pose little additional risk to crewmembers, additional medical monitoring capabilities may be required beyond those currently used for the ISS operations. The use of the ISS to simulate aspects of Mars and NEA missions seems practical, and it is recommended that planning begin soon, in close consultation with all international partners.

Charles, J. B.↗
NASA NTRS1977

Modulation of Jovian electron intensity in interplanetary space by corotating interaction regions

Large-scale intensity variations of Jovian electrons in the energy range from 3 to 6 MeV persisting for several days were observed with instrumentation on the Pioneer 10 and Pioneer 11 spacecraft out to several AU from Jupiter along the pre- and post-planetary encounter trajectories. The corotating interaction regions (CIRs), found by Smith and Wolfe (1976) on these missions to be approximately 25-day recurring regions of enhanced magnetic fields bounded by jumps in solar-wind velocity and frequently shocks, are shown to be impenetrable 'barriers' for the Jovian electrons propagating in the interplanetary medium. Thus, the principal electron-intensity variations are due to the modulating effects of CIRs and are not due to either variations in escape rate of electrons from the magnetosphere or interplanetary electron acceleration. The implications for electron observations at the orbit of earth are discussed.

Conlon, T. F.↗
NASA NTRS2014

Investigation of HZETRN 2010 as a Tool for Single Event Effect Qualification of Avionics Systems

NASA's future missions are focused on deep space for human exploration that do not provide a simple emergency return to Earth. In addition, the deep space environment contains a constant background Galactic Cosmic Ray (GCR) radiation exposure, as well as periodic Solar Particle Events (SPEs) that can produce intense amounts of radiation in a short amount of time. Given these conditions, it is important that the avionics systems for deep space human missions are not susceptible to Single Event Effects (SEE) that can occur from radiation interactions with electronic components. The typical process to minimizing SEE effects is through using heritage hardware and extensive testing programs that are very costly. Previous work by Koontz, et al. [1] utilized an analysis-based method for investigating electronic component susceptibility. In their paper, FLUKA, a Monte Carlo transport code, was used to calculate SEE and single event upset (SEU) rates. This code was then validated against in-flight data. In addition, CREME-96, a deterministic code, was also compared with FLUKA and in-flight data. However, FLUKA has a long run-time (on the order of days), and CREME-96 has not been updated in several years. This paper will investigate the use of HZETRN 2010, a deterministic transport code developed at NASA Langley Research Center, as another tool that can be used to analyze SEE and SEU rates. The benefits to using HZETRN over FLUKA and CREME-96 are that it has a very fast run time (on the order of minutes) and has been shown to be of similar accuracy as other deterministic and Monte Carlo codes when considering dose [2, 3, 4]. The 2010 version of HZETRN has updated its treatment of secondary neutrons and thus has improved its accuracy over previous versions. In this paper, the Linear Energy Transfer (LET) spectra are of interest rather than the total ionizing dose. Therefore, the LET spectra output from HZETRN 2010 will be compared with the FLUKA and in-flight data to validate HZETRN 2010 as a computational tool for SEE qualification by analysis. Furthermore, extrapolation of these data to interplanetary environments at 1 AU will be investigated to determine whether HZETRN 2010 can be used successfully and confidently for deep space mission analyses.

Rojdev, Kristina↗
NASA NTRS1972

Performance of recoverable single and multiple space tugs for missions beyond earth escape

A recoverable space tug launched by the space shuttle to provide the required post-orbital propulsion needed for placement of unmanned satellites is described. The space tug will also be used to launch interplanetary spacecraft from low earth orbit. The performance of single and multiple space tugs (in tandem) for launching spacecraft beyond earth escape is summarized. Trajectories are developed that allow recovery of the tugs whenever practical. The effects of important tug and trajectory parameters on performance are presented. It is concluded that a single tug can inject spacecraft to Mars or Venus and still be recovered. The use of several tugs in tandem can provide a significant increase in capability over the use of a single tug. The more difficult missions involve a mix of recovered and expended tugs.

Zimmerman, A. V.↗
NASA NTRS2008

The DAWN Project's Transition to Mission Operations: on Its Way to Rendezvous with (4) Vesta and (1) Ceres

Dawn launched on 27 September 2007 on a mission to orbit main belt asteroids (4) Vesta in 2011 - 2012 and (1) Ceres in 2015. The operations team conducted an extensive set of assessments of the engineering subsystems and science instruments during the first 80 days of the mission. A major objective of this period was to thrust for one week with the ion propulsion system to verify flight and ground systems readiness for typical interplanetary operations. Upon successful conclusion of the checkout phase, the interplanetary cruise phase began, most of which will be devoted to thrusting. The flexibility afforded by the use of ion propulsion enabled the project to accommodate a launch postponement of more than 3 months caused by a combination of launch vehicle and tracking system readiness, unfavorable weather, and then conflicts with other launches. Even with the shift in the launch date, all of the science objectives are retained with the same schedule and greater technical margins. This paper describes the conclusion of the development phase of the project, launch operations, and the progress of mission operations.

launch operations↗
NASA NTRS1969

Comments on the feasibility of developing gas core nuclear reactors

Recent developments in the fields of gas core hydrodynamics, heat transfer, and neutronics indicate that gas core nuclear rockets may be feasible from the point of view of basic principles. Based on performance predictions using these results, mission analyses indicate that gas core nuclear rockets may have the potential for reducing the initial weight in orbit of manned interplanetary vehicles by a factor of 5 when compared to the best chemical rocket systems. In addition, there is a potential for reducing total trip times from 450 to 500 days for chemical systems to 250 to 300 days for gas core systems. The possibility of demonstrating the feasibility of gas core nuclear rocket engines by means of a logical series of experiments of increasing difficulty that ends with ground tests of full scale gas core reactors is considered.

Rom, F. E.↗
NASA NTRS1974

Description of the meteoroid detection experiment flown on the Pioneer 10 and 11 Jupiter flyby missions

The meteoroid detection experiment has the objective of measuring the population of 10 to the minus 9th power and 10 to the minus 8th power grams mass particles in interplanetary space with emphasis on making these measurements in the Asteroid Belt. The instrument design, which uses the pressurized-cell-penetration detection technique, and the tests involved in obtaining a flight-qualified instrument are described. The successful demonstration of flight-quality penetration detectors to function properly under long-term simulated space environments is also described.

Oneal, R. L.↗
NASA NTRS1975

SOLPRO: A computer code to calculate probabilistic energetic solar proton fluences

A code was developed for the calculation of interplanetary solar proton fluences at 1 AU for the active years 1977 to 1983. The fluences are presented as functions of mission duration tau, energy threshold E, and confidence level Q. For a given combination of tau and Q, the routine determines whether ordinary or anomalously large events are to be considered, and in the latter case, the number of anomalously large events that are predicted by probabilistic theory for the specified mission duration. The code is described in detail. A listing and sample calculations are included.

Stassinopoulos, E. G.↗