Pablo de León

Microbial succession in an inflated lunar/Mars analog habitat during a 30-day human occupation

BackgroundFor potential future human missions to the Moon or Mars and sustained presence in the International Space Station, a safe enclosed habitat environment for astronauts is required. Potential microbial contamination of closed habitats presents a risk for crewmembers due to reduced human immune response during long-term confinement. To make future habitat designs safer for crewmembers, lessons learned from characterizing analogous habitats is very critical. One of the key issues is that how human presence influences the accumulation of microorganisms in the closed habitat.ResultsMolecular technologies, along with traditional microbiological methods, were utilized to catalog microbial succession during a 30-day human occupation of a simulated inflatable lunar/Mars habitat. Surface samples were collected at different time points to capture the complete spectrum of viable and potential opportunistic pathogenic bacterial population. Traditional cultivation, propidium monoazide (PMA)–quantitative polymerase chain reaction (qPCR), and adenosine triphosphate (ATP) assays were employed to estimate the cultivable, viable, and metabolically active microbial population, respectively. Next-generation sequencing was used to elucidate the microbial dynamics and community profiles at different locations of the habitat during varying time points. Statistical analyses confirm that occupation time has a strong influence on bacterial community profiles. The Day 0 samples (before human occupation) have a very different microbial diversity compared to the later three time points. Members of Proteobacteria (esp. Oxalobacteraceae and Caulobacteraceae) and Firmicutes (esp. Bacillaceae) were most abundant before human occupation (Day 0), while other members of Firmicutes (Clostridiales) and Actinobacteria (esp. Corynebacteriaceae) were abundant during the 30-day occupation. Treatment of samples with PMA (a DNA-intercalating dye for selective detection of viable microbial population) had a significant effect on the microbial diversity compared to non-PMA-treated samples.ConclusionsStatistical analyses revealed a significant difference in community structure of samples over time, particularly of the bacteriomes existing before human occupation of the habitat (Day 0 sampling) and after occupation (Day 13, Day 20, and Day 30 samplings). Actinobacteria (mainly Corynebacteriaceae) and Firmicutes (mainly Clostridiales Incertae Sedis XI and Staphylococcaceae) were shown to increase over the occupation time period. The results of this study revealed a strong relationship between human presence and succession of microbial diversity in a closed habitat. Consequently, it is necessary to develop methods and tools for effective maintenance of a closed system to enable safe human habitation in enclosed environments on Earth and beyond.

NDX-2: Development of an Advanced Planetary Space Suit Demonstrator System for the Lunar Environment

In 2009 the Space Suit Laboratory of the University of North Dakota began the development of an advanced lunar EVA suit prototype termed the NDX-2 (North Dakota eXperimental 2) under a NASA grant. The NDX-2 has incorporated the improvements achieved during the earlier NDX-1 Mars space suit demonstrator program. After the numerous lessons learned during the development of the NDX-1 Program, new advanced systems were undertaken that, due to time and budgetary constraints, could not be applied to the NDX-1. Also, after careful examination of the methods foreseen for lunar exploration, we arrived at the conclusion that the new suit system would require a specific donning/doffing capability and method that was not contemplated by the NDX-1. Rear-entry (for don/doff), as opposed to the Shallow Dual-Planar type entry (as was used on the NDX-1), would have most likely been employed as part of the Constellation Extravehicular Activity (EVA) lunar missions, if that mission had materialized. Beyond the inclusion of a rear-entry closure, improved, new type torso structure, shoulder, arm, hip, knee, and ankle joint designs were also incorporated, along with improved joint restraint methods. Accordingly the NDX-2 was configured in such a manner that it could be eventually modified to interface with a suitport airlock, capable of allowing the rear-entry closure to dock directly to a habitat or vehicle, thus avoiding dust intrusion into the cabin. Design constraints/assumptions, construction techniques and preliminary results will be presented in this paper.

Textile Antennas for Spacesuit Applications: Design, simulation, manufacturing, and testing of textile patch antennas for spacesuit applications.

This article presents the design, simulation, manufacturing, and testing of textile patch antennas for spacesuit applications at the frequency 2.45 GHz. Antennas are designed for dispersed placement on two suit prototypes, NDX-1 and NDX-2, both external to the suit and mounted on the inner wall of a removable, thermal layer. Movement of the wearer, along with the necessity of compact transport and the harsh conditions of the extraterrestrial environment, call for durable and flexible antenna materials. Nickel-copper ripstop was selected as the best material for the patch and ground, and layered ultrafirm fabric stabilizer was used for the dielectric. Spray adhesive joined the patch to substrate to ground. Several rounds of antenna design and manufacture were carried out to create the best-performing design. This design of this patch is 52.122-mm long, 58.375-mm wide, with substrate dimensions of 127.52 mm x 127.52 mm, with a height of 1.6 mm. Simulation and experimental results, including co- and cross-polarization patterns in the E- and H-plane and return loss for planar and conformal antenna configurations are presented and discussed. Results indicate that minimal antenna flexure (radius = 101.6 mm) slightly degrades antenna performance and causes a shift in resonant frequency up to 0.02 GHz. Increased flexure (down to a 43.2-mm radius), did not significantly alter radiation patterns or return loss. Extreme bending (<;43.2-mm radius), while not quantified in this article, resulted in severely degraded performance, thus placement of antennas on the suit must limit antenna flexure to ensure desired performance.

A Heart Monitoring System for a Mobile Device

There have been major advances in research and development of devices for the diagnosis of patients in the medical field. A light and portable wireless system to monitor human physiological signals has been always a medical personnels dream. An e-health monitoring system is a widely used noninvasive diagnosis tool for an ambulatory patient who may be at risk from latent life threatening cardiac abnormalities. The authors proposed a high performance and intelligent wireless measuring e-health monitoring system for a mobile device that is characterized by the small sized and low power consumption. The hardware system consists of an one-chip microcontroller Atmega 128L, a wireless module, and electrocardigram ECG signal preprocessing including filtering, power noise canceling, and level shifting. The software utilizes a recursive filter and preprocessing algorithm to detect ECG signal parameters, i.e., QRS-complex, Q-R-T points, HR, and QT-interval. To easily interface with a mobile device, an analyzer program operates on a Windows mobile OS. This paper described the system that was developed and successfully tested for a wireless transmission of ECG signals to a mobile device.

The Development of a Planetary Suit Concept Demonstrator by the North Dakota Space Grant Consortium

Over a one-year period beginning in March, 2005, and with a materials budget of approximately

Crew Protection, Contingency EVA and the Crew Exploration Vehicle

25,000, the North Dakota Space Grant Consortium developed a pressurized planetary space suit concept demonstrator in conjunction with institutions of higher education across the state. This project sought to combine educational instruction in space suit design and manufacturing while simultaneously developing a usable test article incorporating technical approaches appropriate to the project’s schedule and budgetary constraints. The North Dakota Experimental (NDX) Suit serves as a testbed for new planetary suit materials and component assemblies. Designed around a dual-plane enclosure ring built on a composite hard upper torso (HUT), the NDX is designed for an operating differential pressure of 26.2 kPa. In order to test a twochamber suit concept, the NDX features a neck dam assembly that divides the helmet breathing cavity from the body below the neck. For safety purposes during testing, this helmet is also quickly removable. All restraint layer joints and fabric assemblies are sewn with readily available materials and equipment and are ruggedly constructed for a long-duration test campaign. Because of the geographical distances between different component groups, all suit assemblies are designed to be modular and adjustable upon final suit integration. The NDX pressure bladder is a sewn fabric garment coated with latex made to the same dimensions as the restraint layer. The NDX features a backpack that conforms to the HUT and houses communications equipment. Life support system gases are provided to the suit through umbilicals from a separate supply. Wireless biomedical sensors mounted inside the suit and helmet monitor such parameters as heart rate, respiration rate, carbon dioxide concentration, oxygen concentration, body temperature, and relative humidity. This telemetry is sent to a base station via a Bluetooth® hub for monitoring and recording. An evaluation program in both a laboratory setting and at a field site is designed to test performance and usability while ensuring safety. Ultimately, this project has provided a baseline set of knowledge for further planetary research and development within the state of North Dakota.

Stretching effect on textile antenna for spacesuit

ABSTRACT The proposed NASA Crew Exploration Vehicle CEV) has been labeled “not as a( repetition of Apollo, but instead what Apollo should have been.” While this designation is certainly ripe for debate, there is no debating that the space suit community has, up to this point, had limited or no input into the on-going design of the CEV. However, it is important that the community take the opportunity to influence the configuration of the proposed CEV so as to optimize its orbital and planetary/lunar EVA capability, flexibility and safety. This “window of opportunity” will not remain open for long, as the CEV’s configuration is rapidly congealing. This paper covers: 1. Brief space suit configurations, employment and history. 2. Brief descriptions and comparisons of IVA, EVA and IEVA space suits. 3. How history can be a guide to optimize EVA for the Crew Exploration Vehicle. INTRODUCTION An oft used axiom is “those who ignore history are fated to repeat its mistakes.” Unfortunately that old hackneyed aphorism holds as true today as ever. Perhaps with the benefit of alittle hindsight, however, we can avoid a few of its pitfalls. As the space suit community begins its cycle of concept, design and development of a space suit for NASA’s proposed CEV (Crew Exploration Vehicle), we need to carefully, and without bias, consider what worked well and what didn’t work so well, in the past. The proposed CEV, being conceived roughly along the lines of the 1960’s Apollo spacecraft (though larger), looks to still have a verycramped internal cabin, certainly in comparison to the present Space Shuttle Transportation System. This internal crew volume and stowage restriction will have a profound influence on the design drivers affecting any IVA/EVA systems employed. Still, it seems self-evident that some type of personal crew protect will be required on the CEV for launch, reentry and in cases of cabin atmosphere contamination. Moreover, some type of intravehicular space suit may have to be employed that has a contingency extravehicularfunction. The configuration of space suit that is to be used as crew protection for the CEV, if any, has yet to be determined. Will the CEV use a purely IVA suit with only IVA design requirements? Or will it use an IVA suit only during launch, reentry, etc. and employ a separate EVA suit for activities outside the space vehicle? Or will the CEV use a suit system, as was utilized during Apollo, that performed both functions (IEVA)? If this system (IVA/EVA/IEVA) is to be a purely, dedicated IVA suit, or a separate, dedicated EVA suit system, or a combination of the two, then we must determine this criteria very early in the program. We must also quantify and express this criteria while keeping in

Wearable antenna design for spacesuit

Textile and flexible antennas are prone to stretch. This is especially important in spacesuit applications where the suit is pressurized. In this paper we propose a monopole textile antenna placed on a flexible electromagnetic band gap (EBG) ground that is made on flexible substrate. The antenna is designed for on-body communication system of spacesuit. The system is designed for 5.8 GHz band. In normal condition the antenna gain with the EBG structure at 5.8 GHz is 7.02dBi. Simulation results are shown for the antenna under stretching individually and when it is integrated with the EBG.

Preliminary results of mental workload and task engagement assessment using electroencephalogram in a space suit

A textile co-planar monopole antenna is designed with electromagnetic band gap (EBG) structure for on body communication system of a spacesuit. The monopole antenna has -10dB bandwidth from 2.8 GHz to 10 GHz. The communication system is designed for 5.8 GHz band. The antenna gain at 5.8 GHz has been improved by 3.55dB by introducing EBG. Simulation results are shown for the single antenna, antenna integrated with the EBG, and when the antenna with EBG is placed on the part of the chest of the spacesuit.

Interim Report for the Human Exploration of the Moon and Mars: Space radiation protection and mitigation strategies for a long term duration lunar base

In this paper, we present preliminary results of subjects mental workload and task engagement assessment in an experimental space suit. We have quantified the mental workload and task engagement based on changes in electroencephalogram (EEG). EEG signals were collected from subjects scalp using a commercial wireless EEG device in two experimental conditions - when subjects did not wear space suit (control condition) and when subjects wore space suit. Brain state changes were estimated and compared with the direct responses for different tasks and different conditions. We found that the spacesuit experiment introduced a greater mental workload where subjects stress levels were higher than control experiment.