Planet-B mission to Mars - 1998

PLANET-B is the Japanese Mars orbiter program. The primary objective of the program is to study the Martian aeronomy, putting emphasis on the interaction of the Martian upper atmosphere with the solar wind. The launch of the spacecraft is scheduled for August, 1998. The periapsis altitude and the apoapsis are 150 km and 15 Mars radii, respectively. The dry weight of the orbiter is 186 kg including 14 science instruments. Advanced technologies are employed in the design of the spacecraft in order to overcome the weight limitation. This paper describes the scientific objectives of the PLANET-B program and outline of the spacecraft system.     

The gamma-ray observatory mission objectives and its significance for gamma-ray astronomy

The Gamma Ray Observatory (GRO) is an approved NASA mission, programmed for launch in 1988. Its complement of four detectors has established goals: 1) to study the nature of compact γ-ray sources such as neutron stars and black holes, or objects whose nature is yet to be understood; 2) to search for evidence of nucleosynthesis especially in the regions of supernovae; 3) to study structural features and dynamical properties of our galaxy; 4) to explore other galaxies, especially the extraordinary types such as radio, Seyferts, and quasars; and 5) to study cosmological effects by examining the diffuse radiation in detail. This paper discusses the design, objectives, and expected scientific results of each of the GRO instruments in view of the GRO mission goals.     

Biological life-support systems for Mars mission.

Mars mission like the Lunar base is the first venture to maintain human life beyond earth biosphere. So far, all manned space missions including the longest ones used stocked reserves and can not be considered egress from biosphere. Conventional path proposed by technology for Martian mission LSS is to use physical-chemical approaches proved by the experience of astronautics. But the problem of man living beyond the limits of the earth biosphere can be fundamentally solved by making a closed ecosystem for him. The choice optimum for a Mars mission LSS can be substantiated by comparing the merits and demerits of physical-chemical and biological principles without ruling out possible compromise between them. The work gives comparative analysis of ecological and physical-chemical principles for LSS. Taking into consideration universal significance of ecological problems with artificial LSS as a particular case of their solution, complexity and high cost of large-scale experiments with manned LSS, it would be expedient for these works to have the status of an International Program open to be joined. A program of making artificial biospheres based on preceding experience and analysis of current situation is proposed.     

Radiation issues for piloted Mars mission.

Man is now entering an era of colonizing the moon and exploration of Mars. The crewmembers of a piloted mission to Mars will be exposed to inner belt trapped protons, the outer trapped electrons, and the galactic cosmic radiation. In addition there is always the added risk of acute exposure to a solar particle event. Current radiation risk is estimated using the idea of absorbed dose and ICRP-26, LET-dependent quality factors. In a spacecraft with aluminum walls (2 g cm-2) at solar minimum the calculated dose equivalent is 0.73 Sv for a 406-day mission. Based on the current thinking this leads to an excess cancer mortality in a 35 year male of about 1%. About 75% of the dose equivalent is contributed by HZE particles and target fragments with average quality factors of 10.3 and 20, respectively. The entire concept of absorbed dose, quality factor, and dose equivalent as applied to such missions needs to be reexamined, in light of the fact that less than 50% of the nuclei in the body of the astronaut would have been traversed by a single GCR nuclei in the 406-day mission. Clearly, more biologically relevant information about the effects of heavy ions and target fragments is needed and fluence based risk estimation strategy developed for such long term stays in space.     

Infrared spectrometer PFS for the Mars 94 orbiter

Thin films containing a mixture of aliphatic (glycine) and aromatic (tryptophan or tyrosine) amino acids were exposed to a vacuum ultraviolet radiation (VUV) with wavelenghts 100–200 nm. Dipeptides (glycyl-tryptophan and glycyl-tyrosine) were synthesized in these conditions. We compared the actions of VUV and γ-radiation. Polymerization is an essential step in prebiological evolution and we have shown that this stage probably occured over an early Solar system history.     

The oriented scintillation spectrometer experiment for the gamma-ray observatory

The Oriented Scintillation Spectrometer Experiment (OSSE) for the Gamma Ray Observatory is described. OSSE uses four identical NaI(T1)-CsI(Na) phoswich detectors to provide gamma-ray line and continuum detection capability in the 0.05–10 MeV energy range. Additional gamma-ray and neutron detection capability is achieved above 10 MeV. Each detector has a CsI annular shield and a tungsten alloy collimator which define a 5° × 11° (FWHM) field-of-view. The detectors have independent, single-axis orientation systems which permit offset pointing to provide source-background subtraction. The sensitivity for line gamma rays in the 0.05–10 MeV region will be 2–3 × 10^?5 photons/cm²-s for a 10⁶-second observation period. The several modes of data acquisition and the emphases for the planned observational program are discussed.     

Planetary protection program for Mars 94/96 mission.

Mars surface in-situ exploration started in 1975 with the American VIKING mission. Two probes landed on the northern hemisphere and provided, for the first time, detailed information on the martian terrain, atmosphere and meteorology. The current goal is to undertake larger surface investigations and many projects are being planned by the major Space Agencies with this objective. Among these projects, the Mars 94/96 mission will make a major contributor toward generating significant information about the martian surface on a large scale. Since the beginning of the Solar System exploration, planets where life could exist have been subject to planetary protection requirements. Those requirements accord with the COSPAR Policy and have two main goals: the protection of the planetary environment from influence or contamination by terrestrial microorganisms, the protection of life science, and particularly of life detection experiments searching extra-terrestrial life, and not life carried by probes and spacecrafts. As the conditions for life and survival for terrestrial microorganisms in the Mars environment became known, COSPAR recommendations were updated. This paper will describe the decontamination requirements which will be applied for the MARS 94/96 mission, the techniques and the procedures which are and will be used to realize and control the decontamination of probes and spacecrafts.     

Reliability-based trajectory optimization using nonintrusive polynomial chaos for Mars entry mission

This paper presents the reliability-based sequential optimization (RBSO) method to settle the trajectory optimization problem with parametric uncertainties in entry dynamics for Mars entry mission. First, the deterministic entry trajectory optimization model is reviewed, and then the reliability-based optimization model is formulated. In addition, the modified sequential optimization method, in which the nonintrusive polynomial chaos expansion (PCE) method and the most probable point (MPP) searching method are employed, is proposed to solve the reliability-based optimization problem efficiently. The nonintrusive PCE method contributes to the transformation between the stochastic optimization (SO) and the deterministic optimization (DO) and to the approximation of trajectory solution efficiently. The MPP method, which is used for assessing the reliability of constraints satisfaction only up to the necessary level, is employed to further improve the computational efficiency. The cycle including SO, reliability assessment and constraints update is repeated in the RBSO until the reliability requirements of constraints satisfaction are satisfied. Finally, the RBSO is compared with the traditional DO and the traditional sequential optimization based on Monte Carlo (MC) simulation in a specific Mars entry mission to demonstrate the effectiveness and the efficiency of the proposed method.     

Development of an extreme ultraviolet imaging spectrometer for the BepiColombo mission

Extreme and far ultraviolet imaging spectrometers are proposed for the low-altitude orbiter of the BepiColombo mission. The UV instrument, consisting of the two spectrometers with common electronics, aims at measuring (1) emission lines from molecules, atoms and ions present in the Mercury’s tenuous atmosphere and (2) the reflectance spectrum of Mercury’s surface. The instrument pursues a complete coverage in UV spectroscopy. The extreme UV spectrometer covers the spectral range of 30–150 nm with the field of view of 5.0°, and the spectrum from 130 to 430 nm is obtained by the far UV spectrometer. The extreme UV spectrometer employs multi-layer coating technology to enhance its sensitivity at particular emission lines. This technology enables us to identify small ionospheric signatures such as He II (30.4 nm) and Na II (37.2 nm), which could not be detected with conventional optics.     

Applying fuzzy bi-dimensional scenario-based model to the assessment of Mars mission architecture scenarios

Sending man to Mars has been a long-held dream of humankind. NASA plans human planetary explorations using approaches that are technically feasible, have reasonable risks and have relatively low costs. This study presents a novel Multi-Attribute Decision Making (MADM) model for evaluating a range of potential mission scenarios for the human exploration of Mars. The three alternatives identified by the Mission Operations Directorate (MOD) at the Johnson Space Center (JSC) include split mission, combo lander and dual scenarios. The proposed framework subsumes the following key methods: first, the conjunction method is used to minimize the number of alternative mission scenarios; second, the Fuzzy Risk Failure Mode and Effects Analysis (RFMEA) is used to analyze the potential failure of the alternative scenarios; third, the fuzzy group Real Option Analysis (ROA) is used to estimate the expected costs and benefits of the alternative scenarios; and fourth, the fuzzy group permutation approach is used to select the optimal mission scenario. We present the results of a case study at NASA’s Johnson Space center to demonstrate: (1) the complexity of mission scenario selection involving subjective and objective judgments provided by multiple space exploration experts; and (2) a systematic and structured method for aggregating quantitative and qualitative data concerning a large number of competing and conflicting mission events.     

An alternative approach to solar system exploration providing safety of human mission to Mars.

For systematic human Mars exploration, meeting crew safety requirements, it seems perspective to assemble into a spacecraft: an electrical rocket, a well-shielded long-term life support system, and a manipulator-robots operating in combined "presence effect" and "master-slave" mode. The electrical spacecraft would carry humans to the orbit of Mars, providing short distance (and low signal time delay) between operator and robot-manipulators, which are landed on the surface of the planet. Long-term hybrid biological and physical/chemical LSS could provide environment supporting human health and well being. Robot-manipulators operating in "presence effect" and "master-slave" mode exclude necessity of human landing on Martian surface decreasing the level of risk for crew. Since crewmen would not have direct contact with the Martian environment then the problem of mutual biological protection is essentially reduced. Lightweight robot-manipulators, without heavy life support systems and without the necessity of returning to the mother vessel, could be sent as scouts to different places on the planet surface, scanning the most interesting for exobiological research site. Some approximate estimations of electric spacecraft, long-term hybrid LSS, radiation protection and mission parameters are conducted and discussed.     

Issues of exploration: human health and wellbeing during a mission to Mars.

Today, the tools are in our hands to enable us to travel away from our home planet and become citizens of the solar system. Even now, we are seriously beginning to develop the robust infrastructure that will make the 21st century the Century of Space Travel. But this bold step must be taken with due concern for the health, safety and wellbeing of future space explorers. Our long experience with space biomedical research convinces us that, if we are to deal effectively with the medical and biomedical issues of exploration, then dramatic and bold steps are also necessary in this field. We can no longer treat the human body as if it were composed of muscles, bones, heart and brain acting independently. Instead, we must lead the effort to develop a fully integrated view of the body, with all parts connected and fully interacting in a realistic way. This paper will present the status of current (2000) plans by the National Space Biomedical Research Institute to initiate research in this area of integrative physiology and medicine. Specifically, three example projects are discussed as potential stepping stones towards the ultimate goal of producing a digital human. These projects relate to developing a functional model of the human musculoskeletal system and the heart.     

Radiation environment due to galactic and solar cosmic rays during manned mission to Mars in the periods between maximum and minimum solar activity cycles.

A possibility of a manned mission to Mars without exceeding the current radiation standards is very doubtful during the periods of minimum solar activity since the dose equivalent due to galactic cosmic rays exceeds currently recommended standards even inside a radiation shelter with an equivalent of 30 g cm-2 aluminum. The radiation situation at the time of maximum solar activity is determined by the occurrence of major solar proton events which are exceedingly difficult to forecast. This paper discusses the radiation environment during a manned mission to Mars in the years between minimum and maximum solar activity when the galactic cosmic ray intensity is considerably reduced, but the solar flare activity has not yet maximized.     

Radiation environment monitoring for manned missions to Mars.

In this paper a radiation monitoring system for manned Mars missions is described, based on the most recent requirements on crew radiation safety. A comparison is shown between the radiation monitoring systems for Earth-orbiting and interplanetary spacecraft, with similarities and differences pointed out and discussed. An operational and technological sketch of the chosen problem solving approach is also given.     

Russian payload for “interhelioprobe” (“interhelios”) mission

The solar and heliospheric instruments proposed to study the solar atmosphere at close distances and the inner heliosphere onboard the Interhelioprobe mission are described. Remote observations of the solar surface combined with in-situ measurements at optimum orbital parameters (quasi-corotation with the Sun, multiple positions with respect to the Sun-Earth line, and inclination to the ecliptic plane) provide new information on the fine structure and dynamics of the solar surface, solar flares and ejections, solar corona, and solar wind.     

High precision dynamic model and control considering J2 perturbation for spacecraft hovering in low orbit

For spacecraft hovering in low orbit, a high precision spacecraft relative dynamics model without any simplification and considering J₂ perturbation is established in this paper. Using the derived model, open-loop control and closed-loop control are proposed respectively. Gauss's variation equations and the coordinate transformation method are combined to deal with the relative J₂ perturbation between the two spacecraft. The sliding mode controller is adopted as the closed-loop controller for spacecraft hovering. To improve the control accuracy, the relative J₂ perturbation is regarded as a known parameter term in the closed-loop controller. The external uncertainty perturbations except J₂ perturbation are estimated by numerical difference method, and the boundary layer method is used to weaken the impact of chattering on the sliding mode controller. The open-loop control of spacecraft hovering with the relative J₂ perturbation and without the relative J₂ perturbation are simulated and compared, and the results prove that the accuracy of open-loop control with relative J₂ perturbation has been significantly improved. Similarly, the simulation of the closed-loop control are presented to validate the effectiveness of the designed sliding mode controller, and the results demonstrate that the designed sliding mode controller including the derived relative J₂ perturbation can guarantee the high accuracy and robustness of spacecraft hovering in long-term mission.     

MELISSA: a potential experiment for a precursor mission to the Moon.

MELISSA (Micro-Ecological Life Support System Alternative) has been conceived as a micro-organism based ecosystem intended as a tool for developing the technology for a future artificial ecosystem for long term space missions, as for example a lunar base. The driving element of MELISSA is the recovering of edible biomass from waste, CO2, and minerals with the use of sun light as energy source. In this publication, we focus our attention on the potential applications of MELISSA for a precursor mission to the Moon. We begin by a short review of the requirements for bioregenerative Life Support. We recall the concept of MELISSA and the theoretical and technical approaches of the study. We present the main results obtained since the beginning of this activity and taking into account the requirements of a mission to the Moon we propose a preliminary experiment based on the C cycle of the MELISSA loop.     

A consensus approach to planetary protection requirements: recommendations for Mars lander missions.

Over the last several years, the nature of the surface conditions on the planet Mars, our knowledge of the growth capabilities of Earth organisms under extreme conditions, and future opportunities for Mars exploration have been under extensive review in the United States and elsewhere. As part of these examinations, in 1992 the US Space Studies Board made a series of recommendations to NASA on the requirements that should be implemented on future missions that will explore Mars. In particular, significant changes were recommended in the requirements for Mars landers, changes that significantly alleviated the burden of planetary protection implementation for these missions. In this paper we propose a resolution implementing this new set of recommendations, for adoption by COSPAR at its 30th meeting in Hamburg. We also discuss future directions and study areas for planetary protection, in light of changing plans for Mars exploration.     

Solar particle event organ doses and dose equivalents for interplanetary crews: variations due to body size.

Proper assessments of spacecraft shielding requirements and concomitant estimates of risk to critical body organs of spacecraft crews from energetic space radiation require accurate, quantitative methods of characterizing the compositional changes in these radiation fields as they pass through the spacecraft and overlying tissue. When estimating astronaut radiation organ doses and dose equivalents it is customary to use the Computerized Anatomical Man (CAM) model of human geometry to account for body self-shielding. Usually, the distribution for the 50th percentile man (175 cm height; 70 kg mass) is used. Most male members of the U.S. astronaut corps are taller and nearly all have heights that deviate from the 175 cm mean. In this work, estimates of critical organ doses and dose equivalents for interplanetary crews exposed to an event similar to the October 1989 solar particle event are presented for male body sizes that vary from the 5th to the 95th percentiles. Overall the results suggest that calculations of organ dose and dose equivalent may vary by as much as approximately 15% as body size is varied from the 5th to the 95th percentile in the population used to derive the CAM model data.