Irene Borillo Llorca Rajarshi Chattopadhyay *Benjamin Mellman ...

1

_____________________________________________________

Variable Gravity Habitats for Space Operations, Exploration, and

Research

Team Members: Matthew Adams Colin Adamson Ashok Bhattarai

*Irene Borillo Llorca Brianna Brassard

*Rajarshi Chattopadhyay Kyle Cloutier

Alexander Downes Charle Du Toit

Matthew Feeney Kevin Ferguson Samuel Garay Irving Garcia Kurt Conter

Donald Gregorich Matthew Horowitz

Michael Kantzer Jennifer King

Chandan Kittur Douglas Klein Rubbel Kumar

Sahin Kunnanth Sarin Kunnanth Edward Levine

*Benjamin Mellman Atin Mittra

Ryan Moran *Brooks Muller

*Oliver Ortiz William Ouyang

Pegah Pashai Mihir Patel

Brandyn Phillips Nitin Raghu

*Michael Schaffer Mark Schneider

Michael Challcross Daniel Todaro

Cody Toothaker Mazi Wallace Kristy Weber *Kyle Zittle

University of Maryland at College Park

Faculty Advisors: Dr. David Akin & Dr. Mary Bowden Graduate Mentor: Jarred Young

_____________________________________________________

2

1. Table of Contents

2. OVERALL SYSTEM ARCHITECTURE.................................................................................... 1 2.1. MISSION TIMELINE ........................................................................................................................... 1 2.2. SPACE LAUNCH SYSTEM .................................................................................................................. 1 2.3. PHASE I – MICROGRAVITY HABITATION AND ARM ................................................................... 1 2.4. PHASE II – VARIABLE GRAVITY SIMULATION .............................................................................. 3 2.5. PHASE III – 1000 DAY DURATION MISSION WITH THE MARS SIM ....................................... 6 2.6. BUDGET .............................................................................................................................................. 7 2.7. POLUS SUBSYSTEMS ....................................................................................................................... 7

2.7.1. Power Generation and Energy Storage ............................................................................... 7 2.7.2. Thermal Control ............................................................................................................................. 8 2.7.3. Propulsion ......................................................................................................................................... 8 2.7.4. Communications ............................................................................................................................. 8 2.7.5. Onboard Computing ..................................................................................................................... 9 2.7.6. Crew Systems ................................................................................................................................... 9

2.8. TECHNOLOGY READINESS LEVEL (TRL) ................................................................................... 10 2.9. MASS BUDGET ................................................................................................................................ 10

3. HABITABILITY TESTING ..................................................................................................... 10 3.1. HARDWARE AND SOFTWARE USED ............................................................................................ 11 3.2. HABITAT WINDOW STUDY .......................................................................................................... 11 3.3. CONTROLLING FOR SIMULATOR SICKNESS ................................................................................ 12 3.4. REALISTIC REPRESENTATION OF VIEW FROM HABITAT ........................................................ 12 3.5. INTERIOR LAYOUT STUDY ............................................................................................................ 12

3.5.1. Volume Testing ............................................................................................................................. 13 3.6. UNDERWATER VARIABLE GRAVITY TESTING ........................................................................... 14

4. CONCLUSION ........................................................................................................................... 15

5. APPENDIX ................................................................................................................................ 16 5.1. COMPLETE MASS BUDGET ........................................................................................................... 16

6. WORKS CITED IN UNABRIDGED REPORT ..................................................................... 20

1

2. Overall System Architecture

This section provides detail on the overall system architecture of a theoretical artificial gravity space station, POLUS. Architectural trade studies and prior work on several enabling designs validate the final embodiment and guide the recommended approach for POLUS. Design for reliability and human safety is a top priority in the consideration of the final POLUS system. Attention to synergistic applications of NASA’s planned current investments was a key factor in the design. POLUS utilizes the Space Launch System (SLS), supports the Asteroid Redirect Mission (ARM), augments the Orion capsule to stay at the cis-lunar destination for over 30 days, and provides airlock based EVA capabilities during all mission phases. Combining logistics and automation by promoting an integral-structure design philosophy—favoring lighter, functionally redundant systems over physically redundant modular solutions—the final POLUS embodiment is a reduced-mass integrated system design solution for a cis-lunar outpost providing variable gravity capabilities in support and preparation for enabling deep space human exploration.

2.1. Mission Timeline

POLUS is broken into three phases (Figure 1). Each phase is supported by one SLS block 1A structural launch. Structural

launches will use a low ΔV, 100-day transfer. The Space-X Falcon Heavy and DragonRider crew vehicle is used for crew transport. Crew launches take

higher ΔV, 4-day transfer. All launches will be from Cape Canaveral.

2.2. Space Launch System

POLUS is broken into three mission phases. Full-scale CAD models were produced of the fairing and station components to verify launch vehicle packing feasibility. The NASA SLS payload fairing dimensions are not completely defined in the available literature, however, sufficient dimensions are available (Singer, 2012) to approximate the cylindrical portion and the fairing height. The fidelity of the curvature of the nose cone in our CAD model (Figure 2) is approximate thus all parts designed for this station and analyzed in the Loads, Structures, and Mechanisms section, are conservatively designed smaller than the known dimensions of the SLS fairing to ensure that the equipment will fit within the SLS Block 1A fairing even if the final dimensions change slightly.

2.3. Phase I – Microgravity Habitation and ARM

Figure 2. SLS Block 1A Fairing CAD Model

Figure 1. Overall Mission Timeline

2

Phase I consists of one 6 month crew rotation of 4 crewmembers. This phase focuses on fulfilling the final segment of ARM, crewed asteroid exploration. During this phase, Polus will rendezvous with the relocated asteroid in selenocentric distant retrograde orbit (SDRO). The SLS launch is scheduled for September of 2021. This enables the crewed portion of Phase I to begin in 2022, as dictated by the ARM timeline. Phase I will be packed into the SLS fairing and launched as shown in Figure 5. The launch support structure transferring the loads of the habitat and upper stage to the floor of the fairing will be the same construction as what is used as the stringer structure for the habitat. The load path will be through the circumference

of the habitat structure. The communications and power tower will be hanging and suspended from the habitat with cables to inhibit transverse motion. During launch, this tower will be in tension. On orbit, the fairing will separate releasing the structure and upper stage will take Phase I

up to SDRO in the stowed configuration (Figure 4). Upon arrival to SDRO, the structure begins to unpack itself and prepare for the arrival of the crew transport vehicle (Figure 6).

1. Photovoltaics (2 deployed, 2 stowed) 2. Communications

3. Thermal Radiators

4. Cryogenic Upper Stage

5. Reaction Control Thrusters

6. Fuel and Oxidizer Tanks (Under Whipple Shield at Blue and Red Dots)

7. Whipple Shielding

8. Robotic Arm

9. Science Payload Orbiter in a Canisterized Dispenser (Yellow box in Figure 4 and Figure

5)

The Orion vehicle will dock with the International Docking System Standard (IDSS) on the bottom of the habitat where the upper stage is located for launch. For this, the upper stage must be removed and set aside for later repurposing as ballasting mass during later phases. The communications and power

Figure 5. Phase I Structural Launch in SLS Fairing

Figure 3. Phase I Timeline

Figure 4. Phase I Stowed Configuration

Figure 6. Phase 1 Deployed

3

tower is attached to the habitat via the airlock tunnel. Astronauts will be capable of traversing between POLUS and the asteroid by EVA via the airlock tunnel, which has side and top egress ports.

In the middle of Phase I, the Phase II structure will be launched. Phase I concludes halfway through 2022.

2.4. Phase II – Variable Gravity Simulation

Phase II consists of three independent crew rotations, with the goal of evaluating the physiological effects of various gravity levels on the human body, and determining differences in operational protocol required for each gravity level. The main structural addition in this phase is the central hub and the infrastructure required to enable rotation for variable gravity. Polus will now have the capability to generate artificial gravity up to 1 g. Each crew rotation will last six months and support six astronauts. The first rotation will be at Lunar gravity, the second will be at Martian gravity, and the third will be at Earth gravity. Halfway through the third crew rotation, the structural launch for Phase III will occur. Phase II will conclude early in 2024.

In preparation for rendezvous and assembly of Phase II structures with Phase I, the robotic arm will remove the communications and power tower, connected to the top of the airlock section via an IDSS. In April of 2022, the middle of Phase I, the Phase II SLS structure launch will occur. It will arrive in August of 2022.

Phase II SLS launch will bring up the required primary and secondary structural elements to enable the station to spin and provide up to earth gravity for the habitat occupants. The launch supplies a central hub (1), 12 wire rope spools (2), transfer tunnels (3), stability arms (4), the ballast support structure (5), and a cryogenic upper stage (6) (Figure 11).

Figure 8. Phase I Configuration

Figure 7. Phase II Timeline

Figure 9. Phase I Prepared for Phase II Rendezvous

4

In LEO, the fairing will separate and the stowed phase two structure will unpack and venture to SDRO using the cryogenic upper stage. Upon arrival in August of 2022, the rendezvous and assembly of Phase II takes place (Figure 10). During this time, backup batteries and communication will be in use because the power tower is disconnected. The tower will interface with the airlock tunnel section on the top of the central hub. The central hub and habitat interface their airlock tunnel sections forming a rigid connection. All airlock tunnel sections are identical. There is an additional airlock tunnel section on the non-habitat side of the central hub in case there is need to replace one of the three vital airlocks.

Upon rigidly connecting the central hub and the habitat, the robotic arm secures the power tower to the central hub and all four photovoltaic arrays deploy, supplying power to the station. Additionally the thermal radiators will rotate 90˚ so their

radiating side will be perpendicular to the top, flat

surface of the habitat. This is done because from now on, the sun will be in the plane of station rotation and it is preferable for radiator performance to have the large radiating panel not have normally incident light from the sun heating them up.

The wire rope system is wired up by

crewmembers during EVA

with assistance from the robotic manipulator. The wire rope system is in a Stewart truss configuration (Figure 14) for passive torsional stability. There are six wire spools for each side of the central hub for a total of 12. Each of the wire ropes are individually controlled by motors and break systems, allowing for active stability control while spinning. The motors serve to retract cable while the breaking system allows the cable to reel out at a controlled rate while the station is spinning. The cables wrap around sheaves on the habitat and return to be fixed on the central hub, thus reducing the loads on the cables but requiring twice the length of cable. These motors and cables are absolutely critical to the overall system design: without them, artifical gravity could not be established during phases II and III. As such, an in-depth analysis was conducted to confirm the torsional strength and durability of such a design.

Figure 11. Phase II Structural Launch in SLS Fairing

Figure 10. Rendezvous of Central Hub and Phase I

Figure 12. Habitat Wire Rope Sheaves

Figure 13. Central Hub and Habitat Rigid Connection

5

A virtue of the Stewart truss wire rope system is that under spinning operations, different cables can be retracted or let out to alter the location of the habitat relative to the nominal location of the habitat in the rotation plane. Thus, this active stability control can counter out-of-rotation-plane wobble induced by external perturbations to the spinning station. All docking operations take place in the rigid, unreeled configuration. Standard spin up operations begins with rotation under the rigid configuration to preload the cables in tension. Then the cables are allowed to slowly reel out. As the radius of rotation increases to the nominal operation, 50 [m] radius, continued thrusting is required in order to achieve and maintain the desired final rotation rate and thus the final desired gravity level.

Additionally, an alternative design consideration utilized a rigid tunnel structure between the central hub and habitat. By utilizing the Stewart truss wire rope system, the overall system sees a weight savings of nearly 10000 kg.

The two SLS structural launch upper stages and two dragon crew launch upper stages are repurposed for the main ballast mass. For the stability arm masses, 12 additional cable spools are used. These cable

spools serve as backup in case the cables in use need to be replaced. The retired spool would be swapped with one of the new spools and station operation can continue with limited down time. Cable life and health will be

carefully monitored through visual inspection via cameras located on the central hub upon reel in and out operations. Additionally, during spinning operations the cable health will be monitored using strain gages and conductive wire integrity sensors.

Due to the physics of rotational dynamics, the centripetal acceleration is dependent on rotation rate and radius from the axis of rotation. The habitat has two floors. Each floor thus has a different radius of rotation and therefore different gravity level. Additionally, the floors of the habitat are flat. Thus the edges of the floors at the walls of the habitat in the plane of rotation are at a slightly further radius than the center of the floor. Thus there are gravity gradients between each floor in addition to along each floor. A summary of the gravity gradients is provided in

Table 1 on the next page.

Figure 14. Stewart Truss Wire Rope Configuration

Figure 15. Phase II Nominal Spinning Operations Configuration

6

Table 1. Phase II Gravity Gradients

Gravity Rotation Rate [RPM]

1st Floor [g]

1st Floor Edge [g]

2nd Floor [g]

2nd Floor Edge [g]

% Change

Lunar 1.59 0.16 0.16 0.17 0.17 3.77

Mars 2.41 0.36 0.37 0.38 0.38 3.77

Earth 3.91 0.96 0.96 1.00 1.00 3.77

During spinning operations, the crew vehicle is located inside the central hub and docked to the proximal end of the central hub air lock tunnel on the habitat side of central hub. Thus, when spun down, the crew can access Orion via the two connected airlock tunnels rigidly connecting the central hub and the habitat. In a contingency, if emergency access to Orion is required, emergency spin down and reel in would simultaneously occur allowing rapid access to the Orion capsule. In the contingency that the station could not spin down, EVA would be required and ascenders would need to be used to traverse the cable system to the central hub. Attempts to minimize this contingency are made in the design of the propulsion and cable systems by attempting to maximize the critical systems’ reliabilities.

2.5. Phase III – 1000 Day Duration Mission with the Mars SIM

Phase III is a simulation of a crewed, Martian surface mission based on the Human Exploration of Mars Design Reference Architecture 5.0. The timeline for this phase is shown in. The structural launch will include a simulated Martian environment, to explore surface operations. Phase III is a 1000 day duration mission supporting a crew of 6 without resupply. The first and

last 6 months of the phase will be at

microgravity, simulating the Earth to Mars transfer time. During the middle 21 months, Polus operates at Martian gravity, simulating a long-duration stay on Mars. The mission concludes in January of 2027.

Figure 16. Phase III Timeline

Figure 18 Mars SIM Interior Layout

Figure 17 Phase III SLS Structural Launch

7

The launch of the third SLS structural launch will occur in November of 2023 of the Polus mission timeline, at the end of Phase II. The packing of the Phase III structure into the SLS fairing is shown in Figure 18. The support structure providing the loading path to the base of the fairing is not depicted. However, the support structure is the same structure used in the first and second SLS launch. There is significant unused volume in the third SLS structural launch. If need be, the fairing packing can be rearranged to add additional items, including replacement parts or extra supplies.

The purpose of the Mars SIM is to enable high fidelity simulation of Martian EVA’s to provide valuable data relating to astronaut performance in Mars gravity and pressure. Two fully suited astronauts entering the Mars SIM will have the ability perform various tasks in Martian conditions. Priorities will include testing ingress and egress methods for potential Mars landers, astronaut mobility on varied terrain, and space suit performance. In addition to providing an area to conduct mobility and stability testing, the terrain simulations will allow crew to perform tests with various forms of sample collection. The goal will be to optimize the tools to be used during sample collection so as to enable astronauts to increase efficiency and sample return. Basic construction tasks may also be tested to ensure a crew can assist in habitat deployment challenges during an actual mission. The Mars SIM is capable of simulating varying degrees of lighting and Martian wind storm conditions to provide valuable data on crew performance in suboptimal surface conditions. The modular design of the Mars SIM grants considerable versatility in experiments. Once the initial phase of testing is completed, additional experiments can be devised based on crew feedback. Conceivably, the Mars SIM could also be upgraded to incorporate simulated regolith for even higher fidelity missions. The addition of regolith would greatly improve sample collection testing. Continued testing in Phase III and beyond will be invaluable in preparing astronauts for future missions to Mars.

2.6. Budget

Assuming seven years of development time followed by three years of vehicle launches to directly support phases I through III, the total operational budget for this program would come to about $21 billion. During the first seven years, approximately $2.2 billion would be required annually for development of the structures and equipment that make up Polus. The following three years are the program’s most expensive, requiring approximately $5.6 billion in total to account for crew launches, structure launches, and continued development costs. After the final crew launch in 2024, continued station maintenance requires less than $1 billion annually.

2.7. POLUS Subsystems

The following sections detail the specialized subsystems necessary for POLUS’ continued successful operation.

2.7.1. Power Generation and Energy Storage

Continuous power will be supplied to POLUS by photovoltaic arrays made from Multi-Junction Gallium Arsenide solar cells with a 30% efficiency. Phase I systems require an average power of 24.7 kW. To meet this requirement, two solar arrays are used with a total mass of 291 kg and total surface area of 104 m2. Phases II and III have power requirements of 37.4 kW and 49.6 kW, respectively. Two more equal sized arrays will be deployed to meet these power requirements. So, Phases II and III will utilize four solar arrays with a total mass of 582 kg and total surface area of 208 m2. The arrays will maintain an orthogonal incidence angle to the sun with alpha joints, which will rotate the arrays around the z-axis at the approximate rate of one degree per day.

The station will be eclipsed from the sun for approximately four hours every six months. POLUS will store energy to power the station during these eclipse periods and for contingency periods in case of photovoltaic failure. Regenerative Alkaline Fuel Cells using gaseous H2 and O2 as reactants, and an

8

electrolyzer to reproduce reactants from water byproduct, will serve as the primary energy storage device. With a total weight of 3600 kg, the cells will be able to supply up to 12 hours of average power or 48 hours of critical power (12 kW), and they provide a 30% mass savings when compared to leading rechargeable batteries. They will be located at the habitat in case of power line failure, while there will also be small Lithium-Ion batteries with a specific energy of 120 W-hr/kg located at the central hub and ballast to power the cable motors and thrusters in case of emergency.

2.7.2. Thermal Control

The thermal control system will keep the habitable area on POLUS between 292 and 300 K, with maintaining room temperature as often as possible. The system includes four resistive heaters, two radiator panels and pumped fluid loops to equalize and regulate temperature. In addition, the habitat will be coated with 0.25 mm Kapton film with an aluminum backing.

During Phase I, the habitat will be in a rolling motion in order to evenly distribute thermal loading. Two of the four heaters will be required for periods of eclipse, which results in a power requirement of 3.5 kW. Under normal operations, heat will be dumped from the station through two radiators placed at one end cap of the habitat. The total surface area required for Phase I is 7.6 m2. Ammonia will be pumped through the radiators in order to transfer heat from the habitat. The ammonia loop will be connected to a water loop, which will run through the walls of the habitat itself.

During Phases II and III, the station will be rotating so the thermal loads will be distributed along the surface of the habitat. In both phases, all four resistive heaters will be required for periods of eclipse, which results in a 7 kW power requirement. The radiators will still use the ammonia and water loops to transfer and dump heat during normal operations, but their total surface area required will be increased. The radiators can be extended and retracted to change surface area, and the maximum surface area required will be 11 m2 during Phase III. There will be two radiators; each is made from aluminum, weighs 750 kg, and is coated in Aeroglaze A-276 due to its high emissivity (0.92).

2.7.3. Propulsion

POLUS utilizes a series of helium fed liquid bipropellant thruster quads mounted on the habitat and ballast in order to execute spin maneuvers to Earth, Martian, and Lunar gravity levels. Aerojet R-4D 490N thrusters are used for the primary spin maneuvers, while smaller Aerojet R-1E 111N thrusters provide RCS and stationkeeping capabilities. Both systems utilize monomethylhydrazine as fuel and nitrogen tetroxide as an oxidizer. Additionally, both are flight proven with high TRL’s.

2.7.4. Communications

The proposed architecture to fulfill communication requirements consists of communication modes in three radio-based frequency ranges: UHF/VHF, S-band, and Ka-band. Low-bandwidth data (1 MBps maximum) will be transmitted with the UHF/VHF antenna, and high-bandwidth data will be transmitted with parabolic reflector antennas in the Ka-band and S-band. These antennas

Ground station network selection was based on the specifications defined by the UHF/VHF, S-band, and Ka-band antennas. For UHF/VHF communications, four viable ground stations included the Wallops Ground Station (VA) and the White Sands Complex (NM) for VHF and the Merrit Island Launch Annex (FL) and the Ponce de Leon Tracking Station (FL) for UHF. For S-band and Ka-band communications, a large number of ground stations were required so that the station antenna could

Figure 19 Antennae Array Structure

9

guarantee uplink and downlink at all times regardless of which part of Earth was in view. As such, the Deep Space Network (DSN) and the Near Earth Network (NEN) were the best options due to the widespread locations of their ground stations.

2.7.5. Onboard Computing

A four-computer system was the design with the least number of computers that still provided two fault tolerance. The system was designed such that, at most, three computers would be on at any given time. The three-computer system allows for voting without standoffs, and would permit the fourth computer to remain in a standby state. In the event of a failure of one computer, the standby computer would be turned on, thus leaving the station with three active computers again. In the event of a second failure, two computers would remain. At this point, using similar techniques that were used in Space Shuttle’s computer system, tolerance for a third fault could be provided. In order to mitigate the effects of radiation, both radiation-hardened (rad-hard) parts and radiation tolerant design will be used.

The MIL-STD-1553, IEEE-355 (SpaceWire), IEE 802.11 (LAN), IEEE 802.3 (Ethernet) are used in combination for the bus architecture. MIL-STD-1553 will be used for most of the bus architecture due to its redundant design and reliability. SpaecWire offers the highest data rate (200 Mbps) for higher resolution video. LAN will be used for communications between the crew on the station and Ethernet is required as a backup for LAN. Like previous systems, the computers and wiring in this design have a TRL of 9, and have been flown on previous missions.

2.7.6. Crew Systems

POLUS’ Atmosphere Control System (ACS) contains a CO2 scrubbing system, an O2 regeneration system, a power supply, sensors, and a temperature and humidity control system. The components

are designed to minimize

Figure 20 Bus Architecture Diagram

Figure 21 O2 Regeneration and CO2 Scrubbing

10

volume, mass, and power consumption. Figure 21 shows the CO2 removal and O2 regenerative system process with the components the selected after performing trade studies.

Additionally, a water recovery system is in place to provide potable water over the long term mission duration. A Vapor Compression Distillation system and Multifiltration Beds provide a low power, low mass, flight proven solution to this problem with an estimated 93% reclamation efficiency.

2.8. Technology Readiness Level (TRL)

NASA’s scale of Technology Readiness ranks a given technology on a scale of 1 to 9, with 1 representing the observation of basic principles and 9 represents that a system has been ‘flight proven’ through successful mission operations. Nearly every component utilized in this design has a TRL of 9 and is proven to operate in space. After being properly sized based on thrust requirements, the selected thrusters were repurposed Aerojet designs. At the time of this writing, the launch vehicles that will be used have TRLs of about 6: the technology has been demonstrated in a relevant environment. All atmosphere and water recovery technology have TRLs of 9, as does the stations waste management systems. Addtionally, all communication hardware onboard Polus has TRL of 9. Some fuel cell technology used for energy storage aboard Polus is still in development, with TRLs of about 4 and 5. Energy collection technology, in the form of solar panels, also holds a TRL of 9. For our system critical Stewart wire rope truss structure, the technology exists, but has not been applied to an operation of this size in space; as such, it is given a TRL of 4.

2.9. Mass Budget

Below is a mass budget for all phases. A comprehensive budget is available in the appendix.

3. Habitability Testing

Preliminary habitability studies were performed in virtual reality in parallel with physical mockup testing. The

motivation for using virtual reality is primarily the speed with which new habitat configurations can be simulated and tested; basic simulations of proposed habitat designs can be completed in as little as a few hours or days (depending on the level of detail required), compared with weeks to construct a full scale physical mockup. In addition, time and budget constraints limited physical mockup testing to a

Phase I Phase II

Phase III

Mass (kg)

Mass (kg)

Mass (kg)

Loads, Structures, & Mechanisms

23000 36300 10600

Crew Systems 8744 3070 23865

Power, Propulsion, & Thermal

8690 4300 3000

Avionics 1745 1313 1004

Mission Planning & Analysis

1759 0 1511

Station Total 40698 44983 40456

Habitat Total 40698 6738 37452

Ballast Total 0 9745 1405

Hub Total 0 28500 1599

Station Total 40698 44983 40456

Table 2 Mass Budget by Subsystem

Table 3 Mass Budget by Location

11

single structure in one configuration, whereas virtual reality was used to simulate several different interior layout configurations as well as a number of auxiliary perspectives and situations.

3.1. Hardware and Software Used

Immersive virtual reality was achieved using the Oculus Rift Development Kit Version 1, which is a low cost consumer virtual reality HMD (Head Mounted Display) targeted at the gaming community. The Rift features a screen which projects separate images to each eye, simulating depth perception, as well of a suite of accelerometers which enable precise head tracking. Together, these features create the sensation of full immersion in the virtual environment. Virtual environments were created from CAD models with the help of the Unreal Development Kit (UDK), a freely available game engine and level editor. The proprietary Autodesk 3D Studio Max (3DS) was used to create collision models for UDK, and also served as an intermediate step in the conversion of file formats between UDK and various CAD suites.

3.2. Habitat Window Study

One application to which virtual reality is extremely suited is simulating the visual effect of rotation which will be perceived by POLUS crewmembers during periods of artificial gravity. It was beneficial to know whether or not this effect has a tendency to induce motion sickness, and, if it did, whether or not the location of windows relative to the plane of rotation correlates to the degree of motion sickness experienced. To accurately reproduce this situation, a habitat simulation of an empty room with

windows on all sides was furnished in UDK and surrounded by a rotating sphere onto which a virtual star-field was superimposed. The sphere was made to rotate at 23.76 °/s about the local horizontal axis and centered at the habitat section. For an observer inside the habitat section, looking out a window at the rotating star-field, this created a visual effect indistinguishable from what would be experienced if the habitat was rotating at 4 revolutions per minute and he was observing stationary stars with respect to the inertial frame. Since local gravity on station is constant with respect to the frame of reference attached to the station, vestibular effects due to rotation are associated only with Coriolis accelerations. These effects were ignored for the purposes of this study. Four subjects went under two different tests. The first one had a high density star field and simulated one level of the rotating habitat with three different window positions relative to the rotational plane of the space station: in-plane of rotation, off-plane of rotation and diagonal. The testing team was conscious that the virtual star field used was

Figure 22: Different possible window locations

Figure 23 Window test results. It combines the results of both tests (high density and low density star field)

12

not realistic. Therefore, another test with diminished star brightness (0, 0.002 and 0.005) and adding the Sun, Moon and Earth was conducted. To evaluate the tests, the Motion Sickness Assessment Questionnaire (developed by the Department of Psychology, Pennsylvania State University) was used. The study shows that the diagonal windows cause the least motion sickness. When dealing with a lower star field density, the motion sickness decreases, as expected.

3.3. Controlling for Simulator Sickness

In any experimental work involving virtual reality, the effects of so called “simulator sickness” must be taken into account. Simulator sickness is similar to traditional motion sickness in that both result from a mismatch between visually perceived motion and motion felt by the body’s vestibular system. However, whereas the term “motion sickness” generally describes effects due to physical motion, which is perceived by the vestibular system but not the eyes, simulator sickness results from simulated motion which is perceived by the eyes and not the vestibular system. Since the head-tracking provided by virtual reality HMDs is not perfect, simulator sickness is a common side-effect of use even in a static virtual environment. Therefore, the simulator sickness experienced by a test subject in the rotating habitat simulation is due not only to seeing rotation that isn’t felt, but also to the hardware’s limited ability to accurately track head position. To isolate the effect of rotation, subjects were asked to report on the discomfort level they felt when exploring an environment in which nothing was moving.

3.4. Realistic Representation of View from Habitat

It should be noted that the virtual star field used to simulate the dynamic view from the station was of a much higher star density and brightness than would actually be experienced by the POLUS crew. It is meant to be viewed as a “worst case” in which rotation is extremely apparent, in order to focus on the relative differences with respect to window placement as opposed to the absolute level of discomfort that a crewmember would truly experience. A simulation was created in which the star field was replaced with revolving spheres simulating the earth, moon, and sun, as well as a dominant directional light which tracked the sun and provided dynamic light to the habitat through the windows. It was found that the sensation of rotation in this simulation was not so readily apparent as to cause discomfort, although it would be desirable to use it to investigate the effect of rapidly changing sunlight incidence in a further study.

3.5. Interior Layout Study

Virtual reality testing was also used to qualitatively assess a selection of proposed interior layouts for general livability comfort during routine tasks. Full, interactive immersion in each proposed habitat interior was achieved by first importing the CAD assembly for each floor into 3DS and creating an accurate collision model which completely surrounded all solid objects in the assembly. The CAD assemblies and associated collisions were then imported into UDK, where proposed models corresponding to the living quarters, work area, and the Mars yard were stacked on top of one another to create a single “station simulator” for each possible permutation of the habitat. The three levels in each permutation were linked with an interactive ladder, allowing subjects to experience the transit between them in virtual reality. Data gathered through testing with these simulators helped members of the Crew Systems team select a final interior layout from several competing proposals. The highest scoring floor plan utilized a “pod hotel” configuration and allowed for the freest crew movement out of the four available options.

In order to finalize the interior layout, hardware tests were conducted to determine favorable interior characteristics based on several canonical designs. The HAVEN habitat is a project under the Space Systems Laboratory at the University of Maryland. It is a cylindrical habitat with a diameter of five

13

meter with a height of 2 meters. In order to use HAVEN for human testing, certain renovations needed to be made. Once renovated, the habitat was used to for the first of a battery of tests that will be conducted to determine an acceptable dimension of volume and area per crewmember.

The exterior of HAVEN needed to be weatherproofed. This was done by inspecting the entire exterior and applying expanding foam and caulk to gaps and holes that rainwater could enter.

3.5.1. Volume Testing

In order to carry out testing, HAVEN was outfitted to take data. Two tables were installed in the interior in order to hold equipment. A computer was installed, in addition to a GoPro camera that was mounted on the wall. The GoPro was set to record compressed video in order to efficiently view the tests. A galley (consisting of a microwave, taster, and coffee pot) was also installed. The testing regiment consisted of four sessions, each of which lasted an hour long. The first test consisted of one test subject. Each

subsequent test added one additional test subject. The same protocol was used for each respective test subject. Each test lasted one hour. Test subjects were given tasks to complete within an hour. Test subjects were given surveys to gauge the degree at which they felt comfortable in the available space. As stated in the respective protocols, the test subjects answered a question in the survey after every task. Note that the scale from “Strongly Disagree” to “Strongly Agree” follows an integer numerical scale from 1 to 7, respectively, with 4 representing “Neither Agree nor Disagree.” Also note that the questionnaire included a second question, which was “The noise level did not affect my ability to perform this task in any way”. The question was answered using the same scale. Task 1 involved preparing food. Task 2 involved eating food. Task 3 involved recording data on a laptop. Task 4 involved sending the data. Task 5 involved writing a response to a provided prompt.

Figure 25 Initial state of Haven habitat Figure 24 Final state of Haven

Figure 26 Haven Galley Figure 27 Haven Workstations

14

The ability of a test subject to perform a task was not greatly affected by the presence of three other test subjects. This may be because of the relatively limited interaction between more than two test subjects. This may also be influenced by the relatively short duration of the tests (which was one hour).

3.6. Underwater Variable Gravity Testing

0

2

4

6

1 2 3 4 5

Ra

tin

g

Task

S1

S2

0

2

4

6

1 2 3 4 5

Ra

tin

g

Task

S1

S2

0

2

4

6

8

1 2 3 4 5R

ati

ng

Task

S1

S2

S30

2

4

6

1 2 3 4 5

Ra

tin

g

Task

S1

S2

S3

Figure 2931 Noise responses for Test 2 (1-Strongly Disagree, 7-Strongly Agree)

Figure 2831 Task responses for Test 2 (1-Strongly Disagree, 7-Strongly Agree)

Figure 310. Task responses for Test 3 (1-Strongly Disagree, 7-Strongly Agree)

Figure 31. Noise responses for Test 3 (1-Strongly Disagree, 7-Strongly Agree)

0

2

4

6

1 2 3 4 5

Ra

tin

g

Task

S1

S2

S3

S40

2

4

6

1 2 3 4 5

Ra

tin

g

Task

S1

S2

S3

S4

Figure 32. Task responses for Test 4 (1-Strongly Disagree, 7-Strongly Agree)

Figure 32. Noise responses for Test 4 (1-Strongly Disagree, 7-Strongly Agree)

15

To better inform the design of the habitat for the three gravity levels that will be experienced throughout the mission – microgravity, lunar gravity, and Mars gravity – a procedure was developed for testing in the University of Maryland’s Neutral Buoyancy Research Facility. A test subject would be weighted so the combined forces of gravity and buoyancy were equal to the force that would be experienced in each of the testing environments. The subject was tested under microgravity, Lunar gravity, and Martian gravity in a neutral body posture (NBP) while “working” on a handheld tablet. Results can be seen in Figure 33.

A second test had the subject climb a ladder at each of the three gravity levels in order to determine if optimal rung spacing was dependent on gravity level. In microgravity, the subject used only their arms with very little effort to scale the ladder. In lunar gravity, they climbed similar to an Earth gravity motion, but adjusted force as to not overshoot the next rung. In Martian gravity, the subject reported no discernable difference from climbing in Earth gravity. These preliminary results suggest that the ideal rung spacing for a ladder is independent of the gravity level it is being used in. A new hypothesis is that the standard one-foot rung spacing is based on human body geometry more than strength and weight. If true, changing rung spacing based on gravity level might be detrimental to ease of traversal.

4. Conclusion

This study has shown that artificial gravity stations are a not necessarily huge projects on the scale of ISS. Rather, they can be accomplished within a $3 billion a year budget cap and can be operational in time to provide critical information on human responses to lunar and Mars gravity before committing to a multiyear Mars mission. POLUS’ cable-based design would be a suitable proof of concept, such that this type of rotating habitat could be adapted to a feasible Earth-Mars human transport vehicle which provides significant gravity levels for the crew on the way to and back from Mars.

Figure 34 NBP in Microgravity (left), Lunar Gravity (middle), Martian Gravity (right)

Figure 35 Ladder Climbing in Microgravity (left), Lunar Gravity (middle), Martian Gravity (right)

16

5. Appendix

5.1. Complete Mass Budget

PHASE I

Total Mass: 40698 PHASE II

Total Mass: 44983 PHASE III

Total Mass: 40456

Structural Launch

Name/ Identifier

Total Mass (kg)

Structural Launch

Name/ Identifier

Total Mass (kg)

Structural Launch

Name/ Identifier

Total Mass (kg)

Habitat (0uter dimensions)

Central Hub (with 2 tunnel sections)

Primary Structure 5600

Central Hub Structure 11000

Mars SIM (exterior dimensions)

Polyethelene layer 3300

Wipple Sheilding 5100

Ballast Structure CPMB

Outer truss structure 6200

Ballast Support Structure 7800

Mars SIM attachment (attaches to hab)

Antenna/Solar Panel tower

Mars SIM (interior) Structure 10600

Aluminized Kapton Surface coating Cables

Robotic Arm 1000

Steel Spools 5500

Radiators(2) 1500 Winches 12000

Comm Tower 300

17

Habitat (inner dimensions)

Crew Systems

Crew Systems

Crew Systems

Life Support Water Supply 1050

Water Supply 1800

Water Supply 4300

Water tank 180

Additional water tank 45

Water Processing Unit 350

Fire detection and suppression 50

Fire Detection and Suppression 20

Fire Detection and Suppression 50

CO2 Removal/O2 regeneration Unit 1300

Airlock Pump (2) 550

N2/N2 Tank 330

O2/O2 Tank 140

Polyethylene 9950

Airlock pump 280

Hygiene Kit 290

Hygiene Kit 540

Food Space suits EVA (*2) 140 Food 8600

Refrigerator 70 IVA (*6) 240 Spacesuits EVA (*2) 140

Microwave oven 10 IVA (*6) 240

Galley sink 30

Waste Management

Plastic Melt Waste Compactor 60

Hygiene

Toilet-Liquid Waste 10

Toilet-Solid Waste 60

Shower 40

Hygiene Kit 65

Hygiene Cleansing station 12

18

Exercise CEVIS 27

TVIS 180

Crew Berths

Berths w/ SPE shelter 4000

Clothes Clothes 290

Laundry system

Advanced Microgravity Compatible, Integrated Laundry System 80

Spacesuits IVA (*4) 160

PPT Radiators 2700

Heaters

Propellant 1660 Propellant 4300 Propellant 3000

Thrusters (6) 150

Solar Arrays (4) 580

Battery 3600

Avionics Sensors 30 Avionics Sensors 8 Avionics Sensors 4

Hab wires 1300 Hab Wires 1200 Wires 1000

Computer System (4 flight computers, 4 laptops) 115 Computer 5

Antennae/mount 240

Contingency antennaes 100

Mass Memory Unit 60

MPA EVA Suits (2*) 140 MPA MPA

Rubber rocks 190

Shuttle MMU (2*) 280

Fans (x12) 6

MMU Nitrogen Replenishment 12 Suits (2x) 140

19

EVA Tethers 100

Suitports (2x) 140

EVA Sample Collection Instruments 150

Floor, stairs, incline 1500

Phase I Orbiter 750

Astronaut Playthings 10

Phase I Science Instruments for Hab Science Lab (Rack) 300

Cameras (x2) 1

Dust VAC 7

Physiology workstation 20

20

6. Works Cited in Unabridged Report

1. Baličević, P., Dražan, K., Tomislav, M., & and Josip, J. (2008). Strength of Pressure Vessels with Ellipsoidal Heads. Journal of Mechanical Engineering , 685-692.

2. Universal Metaltek. (n.d.). Honeylite Aluminum Honeycomb Panel. Retrieved March 2014, from Universal Metaltek: http://www.universalmetaltek.com/pdf/Aluminum-Honeycomb-Panel.pdf

3. United Launch Alliance. (n.d.). Atlas V and Delta IV Technical Summary. Retrieved from United Launch Alliance Homepage: http://www.ulalaunch.com/uploads/docs/Launch_Vehicles/AV_DIV_product_card.pdf

4. UMPQUA Research Company. (2012). Advanced Microgravity Compatible, Integrated Laundry System. Myrtle Creek, Oregon: UMPQUA Research Company.

5. Upper Stage Engines. (2013). Retrieved May 12, 2014, from MOOG Isp: http://www.moog.com/literature/Space_Defense/Spacecraft/Propulsion/Upper_Stage_Engines_Rev_0913.pdf

6. Wertz, J. R. (2011). Space Mission Engineering: The New SMAD. 4th ed. Hawthorne, CA: Microcosm.

7. Wertz, J. R., Everett, D. F., & Puschell, J. J. (2011). Space Mission Engineering: The New SMAD. (J. R. Wertz, D. F. Everett, & J. J. Puschell, Eds.) Hawthorne, CA, USA: Microcosm Press.

8. Wieland, P. (1998). Living Together in Space: The Design and Operation of the Life Support Systems on the International Space Station. Technical Memorandum, NASA, Scientific and Technical Information Program Office, Huntsville.

9. Wittry, J. (2006, September 29). Smoking Out Space Fires: NASA Study Helps Prevent Fires in Space. Retrieved March 2, 2014, from Nasa International Space Station Research: http://www.nasa.gov/mission_pages/station/research/space_smoke.html

10. Woronowicz, M. S. (2000, January 10). Experimental Validation of a Simple Bipropellant Thruster Plume Model . Retrieved May 12, 2014, from AIAA.org: http://arc.aiaa.org/doi/pdf/10.2514/6.2000-598

11. Woronowicz, M. S. (2011, June 27). Highlights of Transient Plume Impingement Model Validation and Applications. Retrieved May 12, 2014, from NASA.gov: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110013451.pdf

12. Xu Ming, X. S. (2009). Exploration of distant retrograde orbits around Moon. Acta Astronautica , 65.

13. Young, W. C., & Budynas, R. G. (2002). Roark's Formulas for Stress and Strain (7th Edition ed.). New York, Ny: McGraw-Hill.

14. (2014). Retrieved from Wise Food Storage: http://wisefoodstorage.com/2880-serving-package.html

15. Augello, G., Nebiolo, M., Carrera, E., Manfredi, L., Bodombo, R., & Gabellini, E. (2005). Investigation of Structural Analysis Themes related to Inflatable Space Structures, by the use of the Non-Linear, Multibody Finite Element Code SAMCEF Mecano. 9th SAMTECH Users Conference 2005. Paris.

21

16. Abercromby, A. F., Chappell, S. P., & Gernhardt, M. L. (2013). Desert RATS 2011: Human and robotic exploration. Acta Astronautica , 34-48.

17. Aerojet Engines on ATV Give Space Station a Big Boost. (n.d.). Retrieved May 12, 2014, from PR Newswire: http://www.prnewswire.com/news-releases/aerojet-engines-on-atv-give-space-station-a-big-boost-125378743.html

18. Aerotech. (1994-2004). ADRS Mechanical-Bearing Direct-Drive Rotary Stage. Retrieved from Aerotech: http://www.aerotech.com/product-catalog/stages/rotary-stages/adrs.aspx?p=%2fproduct-catalog%2fstages%2frotary-stage.aspx%3fbearingType%3dMechanica

19. Akin, D. (2013, january 1). Dave Akin's Website. Retrieved March 1, 2014, from spacecraft.ssl.umd.edu: http://spacecraft.ssl.umd.edu/academics/483F13/483F13L09/483F13L09.life_support.pdf

20. Akin, D. (2013). Space Life Support Systems. College Park, MD.

21. Allton, J. H. (2014). Catalog of Apollo Lunar Surface Geological Sampling Tools and Containers. Retrieved from www.hq.nasa.gov: http://www.hq.nasa.gov/office/pao/History/alsj/tools/Welcome.html

22. Atkinson, N. (2013, April 26). Universe Today. Retrieved 2014, from An Inside Look at the Water/Urine Recycling System on the Space Station: http://www.universetoday.com/101775/an-inside-look-at-the-waterurine-recycling-system-on-the-space-station/

23. Budynas, R. G., & Nisbett, K. J. (2011). Sheigley's Mechanical Engineering Design (9th Ed. ed.). New York, NY: McGraw-Hill.

24. Bailey, V., Cantu, N., Garcia, G., & Orona, M. (2012). Laundry in Space: Gravity Independent Laundry System (GILS). Kingsville, Texas: Texas A&M University.

25. Balachandran, B., & Magrab, E. B. (2004). Vibrations (2nd Edition ed.). Stamford, Ct: Cengage Learning.

26. Barbee, B. W. Guidance and Navigation for Rendezvous and Proximity Operations with a Non-Cooperative Spacecraft at Geosynchronous Orbit. NASA.

27. Barry, P. L. (2011, September 20). Science News. (D. T. Phillips, Editor) Retrieved May 6, 2014, from NASA SCIENCE: http://science1.nasa.gov/science-news/science-at-nasa/2000/ast13nov_1/

28. Beardmore, R. (2013, January 22). Worm Gears. Retrieved from Roymech: http://roymech.co.uk

29. Beegle, L., Peters, G., Bearman, G., Smith, J., & Anderson, R. (2005). Mojave Martian Simulant: A New Martian Soil Simulant. Pasadena, California, United States of America.

30. Boeing. (2014). International Space Station Electrical Power System. Retrieved from http://www.boeing.com/assets/pdf/defense-space/space/spacestation/systems/docs/ISS%20Electric%20Power%20System.pdf

31. Cucinotta, F. A. (2005, July). Managing Lunar and Mars Mission Radiation Risks. Houston, Taxas, USA.

32. Carriere, T. (2012). Fire Suppression Tests Using a Handheld Water Mist Extinguisher Designed for Spacecraft Application. SUPDET 2012. Phoenix, AZ.

33. Carter, D. L. (2009). Status of the Regenerative ECLSS Water Recovery System. Technical Memorandum, NASA, Huntsville, AL.

22

34. Charles, D., Knudson, W., Cunningham, R., Roy, W., Smith, T. H., Gruener, J., et al. (2001). The Mars Surface Reference Mission: A Description of Human and Robotic Surface Activities. Houston, Texas, United States of America.

35. Clyde Space. (2014, May 12). Secondary Batteries. Retrieved from http://www.clyde-space.com/products/spacecraft_batteries/useful_info_about_batteries/secondary_batteries

36. Consultative Committee for Space Data Systems. (2012). Lossless Data Compression. Washington, DC: CCSDS Secretariat.

37. Committee on International Space Station Meteoroid/Debris Risk Management. (1997). Protecting the Space Station from Meteoroids and Orbital Debris. Washington D.C.: National Acadamy Press.

38. Cramer, D. B. (1985). Physiological Considerations of Artificial Gravity. (C. A. Cron, Ed.) Applications of Tethers in Space .

39. Environmental Protection Agency. (2013, June 3). Drinking Water Contaminants. Retrieved 2014, from http://water.epa.gov/drink/contaminants/

40. Encyclopedia Astronautica R-1E. (n.d.). Retrieved May 12, 2014, from Encyclopedia Astronautica: http://www.astronautix.com/engines/r1e.htm

41. Encyclopedia Astronautica R-4D. (n.d.). Retrieved from Encycopedia Astronautica: http://www.astronautix.com/engines/r4d.htm

42. Emerson Process Management. (2012, November). UV/IRS Flame Detector Product Data Sheet. Retrieved 2014, from Emerson Process Management: http://www2.emersonprocess.com/siteadmincenter/PM%20Rosemount%20Analytical%20Documents/FGD_PDS_UV_IRS_Flame_Detector.pdf

43. DuPont. (2001, July). Technical Guide for NOMEX Brand Fiber. Retrieved from http://www.firesleeveandtape.com/NOMEX%20Technical%20Guide.pdf

44. Drinking Water Contaminants. (2013, June 3). Retrieved March 7, 2014, from EPA: Drinking Water: http://water.epa.gov/drink/contaminants/index.cfm#listmcl

45. Fisher, J., & Pace, G. S. (2005). Development of the Plastic Melt Waste Compactor- Design and Fabrication of the Half-Scale Prototype. NASA Ames Research Center.

46. Food Managment. (1971). Habitability Data Handbook .

47. Gilruth, R. R. (1960). Manned Space Stations - Gateaway to out Future in Space. (S. F. Singer, Ed.) Manned Laboratories in Space , 1-10.

48. Graybiel, A. (1975). Some Physiological Effects of Alternation Between Zero Gravity and One Gravity. In J. Grey (Ed.), Space Manufactiuring Facilities (Space Colonies): Proceedings of the Princeton / AIAA / NASA Conference (pp. 137-149). American Institute of Aeronautics and Astronautics.

49. Griffin, D. W. (2009, June 16). LMM Capability Overview. Retrieved from www.nasa.gov: http://www.nasa.gov/pdf/360405main_P15_1110_GRC.pdf

50. (2013). International Docking Systems Standard (IDSS) Interface Definition Document (IDD). International Docking Standard.

51. International Space Station membership. (2013). International Docking System Standard Interface Definition Document. www.internationaldockingstandard.com/download/IDSS_IDD_Rev_C_11_22_13_FINAL.pdf.

23

52. Ishiguro, M. e. (n.d.). The Hayabusa Spacecraft Asteroid Multi-Band Imaging Camera: AMICA. Icarus .

53. Israel, D., & Cornwell, D. (2014). Disruption Tolerant Networking: Demonstrations over LLCD's Optical Links. IPNSIG Space Technology Innovations Conference. Greenbelt: NASA.

54. (2009). Human Exploration of Mars Design Reference Architecture 5.0. NASA.

55. Hutchens, C. F. (2002, June). Vapor Compression Distillation Flight Experiment. Huntsville, AL.

56. Hayleck Jr, C. R. (1965). Analysis of the Motion of a Satellite-Reaction Wheel Assembly Optimized for Weight and Power. Greenbelt: Goddard Space Flight Center.

57. Haines, R. F. (1986). Space Station Proximity Operations and Window Design. NASA Ames Research Center, Aerospace Human Factors Research Division. Moffett Field: NASA.

58. Hanford, A. J. (2004, August). Advanced Life Support Basline Values and Assumptions Document. Retrieved from NASA: http://ston.jsc.nasa.gov/collections/trs/_techrep/CR-2004-208941.pdf

59. Hill, P. R., & Schnitzer, E. (1962). Rotating Manned Space Stations. Astronautics , 7 (9), 14-18.

60. Hoffman, S. J. (2001, December). The Mars Surface Reference Mission: A Description of Human and Robotic Surface Activities. Retrieved from NASA: http://www.nss.org/settlement/mars/2001-NASA-MarsSurfaceReferenceMission.pdf

61. James H. Adams, J. (2001, January 8). Radiation Shielding Materials. 2. Huntsville, AL, USA.

62. JHU APL. (n.d.). NEAR Laser Rangefinder. Retrieved from near.jhuapl.edu: http://near.jhuapl.edu/fact_sheets/NLR.pdf

63. Johnson, J. R., Marten, A. M., & Tellez, G. M. (2012). Design of a High Efficiency, High Output Plastic Melt Waste Compactor. Madison, Wisconsin: ORBITEC.

64. Kuhl, C. A. (2009, March). Design of a Mars Airplane Propulsion System for the Aerial Regional-Scale Environmental Survey (ARES) Mission Concept. Retrieved May 12, 2014, from NASA.gov: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090013211.pdf

65. Kalinski, M. E. (2004). Hypervelocity Impact Analysis of International Space Station Whipple and Enhanced Stuffed Whipple Shield. Monterey, California: Naval Postgraduate School.

66. Keck Institute for Space Studies. (2012). Asteroid Retrieval Feasibility Study. Jet Propulsion Laboratory, California Institute of Technology. Pasadena: NASA JPL.

67. Lunar and Planetary Institute . (2014). Collecting Moon Rocks: Sample Collection Tools. Retrieved from www.lpi.usra.edu: http://www.lpi.usra.edu/lunar/samples/apollo/tools/

68. Lyndon B. Johnson Space Center. (2001). ISS Exercise Countermeasures. Summary of Internation Space Station Countermeasures. Houston, Texas.

69. Lange, K. (2003). Advanced Life Support Requirements Document. NASA, Engineering Directorate - Crew and Thermal Systems Division, Houston, TX.

70. Levine, H. G. (2014, April 30). Forward Osmosis Bag Experiment Details. Retrieved 2014, from http://www.nasa.gov/mission_pages/station/research/experiments/846.html

71. Lindeburg, M. R. (2012). Civil Engineering Reference Manual for the PE Exam. Belmont, CA: Professional Publications Inc.

72. NASA. (2014, May 14). A Day in the Life Aboard the International Space Station: Introduction. Retrieved from

24

http://www.nasa.gov/audience/foreducators/teachingfromspace/dayinthelife/#.U3Ga_K1dVE8

73. NASA. (n.d.). Computers in Spaceflight: The NASA Experience. Retrieved from NASA History: http://history.nasa.gov/computers/Ch3-1.html

74. NASA. (n.d.). Experiment Operations During Apollo EVAs: Lunar Geology Tools. Retrieved from http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/docs/ApolloCat/Part1/GeoTools.htm

75. NASA Exploration Systems Mission Directorate. (2008). Constellation Space Suit System Contract Award Announcement.

76. NASA. (2014). Fuel Cell Power Plants. Retrieved from http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/eps/pwrplants.html

77. NASA Glenn Research Center. (2007, March 9). Light Microscopy Module (LMM). Retrieved from spaceflightsystems.grc.nasa.gov: http://spaceflightsystems.grc.nasa.gov/SOPO/ICHO/IRP/FCF/Investigations/LMM/CVB/documents/LMM-CVB%20Short%20Overview%20Presentation.pdf

78. NASA. (2007). INTERNATIONAL SPACE STATION CATALOGUE Of FLIGHT CREW EQUIPMENT. Houston, Texas: NASA.

79. NASA. (2005). INTERNATIONAL SPACE STATION PROGRAM MANAGEMENT PLAN FOR WASTE COLLECTION AND DISPOSAL. Houston, Texas: NASA, Johnson Space Center.

80. NASA. (2010). Human Integration Design Handbook (HIDH).

81. NASA. (n.d.). Human Space Flight. Retrieved from Shuttle Airlock: http://spaceflight.nasa.gov/shuttle/reference/shutref/structure/airlock.html

82. NASA JPL. (n.d.). Visible and Infrared Spectrometer (VIR) Instrument. Retrieved from dawn.jpl.nasa.gov: http://dawn.jpl.nasa.gov/technology/vir_inter.asp

83. NASA JPL. (n.d.). Gamma Ray and Neutron Detector (GRaND) Instrument. Retrieved from dawn.jpl.nasa.gov: http://dawn.jpl.nasa.gov/technology/GRaND_inter.asp

84. NASA. (1987). Man-System Integration Standards.

85. NASA. (n.d.). Man-Systems Integration Standards: Extravehicular Activity. Retrieved from msis.jsc.nasa.gov: http://msis.jsc.nasa.gov/sections/section14.htm

86. NASA Systems Engineering Handbook . (2007). Washington, D.C.: NASA.

87. NASA. (2001, April). Space RAD Health. 1 . (F. Cucinotta, Ed.) USA.

88. NASA. (2008, November 13). Spacesuits and Spacewalks. (S. Canright, Editor) Retrieved from www.nasa.gov: http://www.nasa.gov/audience/foreducators/spacesuits/home/clickable_suit_nf.html

89. NASA-JSC. (2008, 05 07). msis.jsc.nasa.gov. Retrieved from nasa.gov: http://msis.jsc.nasa.gov/sections/section14.htm

90. Nilsson, J., & Thorstensson, A. (2008). Adaptability in frequency and amplitude of leg movements during human locomotion at different speeds. Acta Physiologica Scandinavica , 129 (1), 107-114.

91. Norton, R. L. (2011). Design of Machinery. McGraw Hill.

25

92. MacDonnell, D. G. (2000). Communications Analysis of Potential Upgrades of NASA's Deep Space Network. College Park: University of Maryland.

93. Martin Marietta & TRW Systems Group. (1973). Systems Design Study of the Pioneer Venus Spacecraft: Final Study Report. NASA Ames Research Center. TRW Systems Group.

94. Miller, P. (2007, Aug 9). Ka-Band-The Future of Satellite Communication? Retrieved May 13, 2014, from Tele-Audiovision.

95. Minton-Summers, C. R. (1996). International Space Station ECLSS Technical Task Agreement Summary Report. Technical Memorandum 108508, NASA, Huntsville, AL.

96. Mitchell, G. (2009). Investigation of Hamming, Reed-Solomon, and Turbo Forward Error Correcting. Sensors and Electron Devices Directorate. Adelphi: U.S. Army Research Laboratory.

97. MSC Software Corp. (n.d.). Workshop 6: Modal Analysis of a Circular Plate. Retrieved March 2014, from MSC.Nastran 101 Exercise Workbook: http://web.mscsoftware.com/support/online_ex/previous_Nastran/Nas101/lesson_06.pdf

98. MRE-15 Monopropellant Thruster. (n.d.). Retrieved May 12, 2014, from Northrop Grumman: http://www.northropgrumman.com/Capabilities/PropulsionProductsandServices/Documents/MRE-15_MonoProp_Thruster.pdf

99. Ostergard, R. (2011). Flywheel Energy Storage: A Conceptual Study. Uppsala University.

100. Personal Hygiene. (1971). Habitability Data Handbook .

101. Petty, J. (2002, April 7). Airlock. Retrieved from National Aeronautic and Space Administration: http://spaceflight.nasa.gov/shuttle/reference/shutref/structure/airlock.html

102. Petty, J. I. (2002, April 7). Food for Space Flight. Retrieved from NASA: http://spaceflight.nasa.gov/shuttle/reference/factsheets/food.html

103. Petty, J. I. (2003, June 27). International Space Station History: TransHab Concept. Retrieved March 2014, from NASA Human Spaceflight: http://www.spaceflight.nasa.gov/history/station/transhab/index.html

104. Planetary Systems Corporation. (2013, August 6). Canisterized Satellite Dispenser (CSD) Data Sheet. Retrieved from planetarysys.com.

105. Surrusco, B. S., Bilén, S. G., & Croskey, C. L. (2004). A Low-Cost, Powerful Flight Computer Design Including Linux and IP Technology for the Low Earth Orbiting Local Ionospheric Measurements Satellite. University Park: The Pennsylvania State University.

106. Sutton, G. P., & Biblarz, O. (2010). Rocket Propulsion Elements. Hoboken, New Jersey, USA: John Wiley & Sons, Inc.

107. Santo, A. G., Lee, S. C., & Gold, R. E. NEAR Spacecraft and Instrumentation. The Johns Hopkins University Applied Physics Laboratory, Laurel, MD.

108. Singer, J. (2012). Space Launch System (SLS) Program Overview. National Aeronautics and Space Administration, Marshall Space Flight Center. Huntsville: NASA.

109. Singer, J. (2012). Space Launch System (SLS) Program Overview. Huntsville: NASA.

110. Simon, M., Whitmire, A., & Otto, C. (2011). Factors Impacting Habitable Volume Requirements: Results from the 2011 Habitable Volume Workshop. Houston, Texas.

111. Sklaroff, J. R. (1976). Redundancy Management Technique for Space Shuttle Computers. Owego: IBM Journal of Research and Development.

26

112. Smith, P. H. (2013). The OSIRIS-REx Camera Suite (OCAMS). Lunar and Planetary Science Conference.

113. Space Exploration Technologies Corp. (2013, April 12). SpaceX Falcon Heavy Fairing. Retrieved March 1, 2014, from http://www.spacex.com/news/2013/04/12/fairing

114. SpaceX. (2009). Falcon 9 Launch Vehicle - Payload User's Guide. Retrieved from SpaceX - Space Exploration Technologies: http://decadal.gsfc.nasa.gov/pace-201206mdl/Launch%20Vehicle%20Information/Falcon9UsersGuide_2009.pdf

115. Sturges. (n.d.). Kevlar Nomex. Retrieved from http://www.sturgesstraps.com/kevlar-nomex/

116. Starr, W. J. (2010). Analysis of Slewing and Attitude Determination Requirements for CTEx. Wright-Patterson Air Force Base: Air Force Institute of Technology.

117. Stich, S. (2014). Asteroid Redirect Mission: Building Human Space Flight Exploration Capabilities. NASA Johnson Space Center.

118. Rebmann, J. ISS Robotics Analysis and Operation. Boeing.

119. Regenerative Life Support For Space Settlers. (n.d.). Retrieved from NASA-Ames Research Center: http://www.nss.org/settlement/nasa/designer/regen.html

120. Rejman, E., & Rejman, M. (2011). Gears Weight Equations - Gear Chain Weight Calculation Methodology. Scientific-Technical Union of Mechanical Engineering , 18-21.

121. Rockwell Collins. (2014). Rockwell Collins. Retrieved March 2014, from Magnetic Bearing Momentum and Reaction Wheel: http://www.rockwellcollins.com/sitecore/content/Data/Products/Space_Components/Satellite_Stabilization_Wheels/Magnetic_Bearing_Momentum_and_Reaction_Wheel.aspx

122. Rodriguez, H., Popp, C., & Rehagan, D. J. (n.d.). X-37 Storable Propulsion System Design and Operations. Retrieved May 12, 2014, from NASA.gov: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060004795.pdf

123. Thomson, W. T., & Fung, Y. C. (1965). Instability of Spinning Space Stations Due To Crew Motion . AIAA Journal , 3 (6), 1082-1087.

124. Toyoshima, M., & Takayama, Y. (2012). Space-based laser communication systems and future trends. 2012 Conference on Lasers and Electro-Optics (CLEO) (pp. 1-2). San Jose: IEEE.

125.






27

















147. Atkinson, N. (2013, April 26). Universe Today. Retrieved 2014, from An Inside Look at the Water/Urine Recycling System on the Space Station:

28

http://www.universetoday.com/101775/an-inside-look-at-the-waterurine-recycling-system-on-the-space-station/



















29




















30













197. NASA. (2014, May 14). A Day in the Life Aboard the International Space Station: Introduction. Retrieved from http://www.nasa.gov/audience/foreducators/teachingfromspace/dayinthelife/#.U3Ga_K1dVE8






31






















32






















33






250.












34


















35




















36




















37





















38





















39




















40

















392. Aerotech. (1994-2004). ADRS Mechanical-Bearing Direct-Drive Rotary Stage. Retrieved from Aerotech: http://www.aerotech.com/product-catalog/stages/rotary-

41

stages/adrs.aspx?p=%2fproduct-catalog%2fstages%2frotary-stage.aspx%3fbearingType%3dMechanica


















42




















43




















44





















45





















46












!

2014%RASC*AL%Compliance%Matrix%

ALL%TEAMS% Page%#%Is!the!overall!system!architecture!addressed!sufficiently?!!! !

Have!you!selected!one!or!more!enabling!design!elements!to!validate!(either!through!detailed!analysis!or!proto:type!development)?! !

Does!your!concept(s)!augment!the!Orion!to!stay!at!the!cis:lunar!destination!for!at!least!30!days!&!provide!an!airlock!based!EVA!capability?! !

Have!you!addressed!reliability!and!human!safety!in!your!design?! !

Have!you!identified!the!appropriate!key!technologies!and!TRLs?! !

Have!you!identified!the!systems!engineering!and!architectural!trades!that!guide!the!recommended!approach?!! !

Have!you!considered!how!the!project!would!be!planned!and!executed?!! !

Have!you!included!a!project!schedule,!including!a!test!and!development!plan?! !

Have!you!included!information!on!annual!operating!costs!(i.e.,!budget))?! !

Have!you!given!attention!to!synergistic!applications!of!NASA’s!planned!current!investments!(within!your!theme!and!beyond)?! !

Have!you!considered!unique!combinations!of!the!planned!elements!with!innovative!capabilities/technologies!to!support!crewed!and!

robotic!exploration!of!the!solar!system?!!

Does!your!scenario!address!novel!applications!with!an!objective!of!NASA!sustaining!a!permanent!and!exciting!space!exploration!program?! !

Will!your!team!faculty!advisor!be!present!during!the!2014!RASC:AL!Forum?!(required)! !

Does!your!abstract!meet!the!5!page!limitation?!(for+submission+with+Abstract+only)! !

Does!your!paper!fall!within!the!10!–!15!page!limitation?!(for+submission+with+Technical+Paper+only)! !

ENABLING%LONG%DURATION%MISSIONS%THROUGH%HOLISTIC%HABITAT%DESIGN! Page%#%o Have!you!identified!methods!for!substantial!(>50%)!mass!reduction!in!the!habitat!system!(including!structures,!support!systems!and!

logistics)?!!

o Have!you!utilized!a!systems!perspective!to!identify!novel!ways!that!any!combination!of!the!following!systems!can!interact/work!together!to!

reduce!mass?!(Select+all+that+apply)!€ Primary/secondary!structure!!!€!Shielding!!!!!!!!!!!!!!!!!!€!Reliability!!!!!!!!!!!!!!!!!!!€!Automation!!!!!!!!!!!!!!!€!!Maintenance!!!!!!!!!!€!Risk!posture!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!€ Logistics!packaging!!!!!!!!!!!!!!!!!!!!€!!Sparing!strategy!(ORU!vs.!board!level)!!!!!!€!Repurpose/reuse/recycle!of!materials!

!

o Have!you!combined!any!or!all!of!the!three!areas!below!into!an!integrated!system!design!solution!to!be!implemented!on!the!cis:lunar!

outpost!in!preparation!for!enabling!human!exploration!of!deep!space!destinations?!(Select+all+that+apply)!€ Reliability,!Maintainability,!and!Automation!!!!!!!!!!!!!!!!!!!!!!!!!€!Structures!!!!!!!!!!!!!!!!!!!!!!!!!!€!Logistics!

!

o Have!you!developed!an!innovative!system/sub:system!prototype?!!! !

o Have!you!validated!the!design!assumptions?! !

o Have!you!examined!the!potential!for!these!same!systems/sub:systems!to!be!operated!in!conjunction!with!NASA’s!proposed!asteroid!

redirect!mission!where!the!facility!would!be!docked!to!the!asteroid!return!vehicle!to!facilitate!crewed!exploration!of!the!returned!asteroidal!

material?!

!

HUMAN*ASSISTED%SAMPLE%RETURN! Page%#%Have!you!focused!on!addressing!one!or!more!of!the!following!issues!regarding!planetary!sample!return!to!a!cis:lunar!spacecraft?!(Select+all+that+apply)+€ Tracking,!capture,!and!docking/berthing!of!a!sample!return!spacecraft!from!multiple!destinations!(in!particular,!NEAS,!Earth’s!moon,!

and!Mars)!

€ Acquisition!of!the!sample!from!a!robotic!carrier!spacecraft!and!safe!transport!into!the!cis:lunar!spacecraft!laboratory!environment!

€ Careful!handling!of!samples!that!may!contain!Mars!microorganisms,!including!contamination!control!

€ In:situ!sample!analysis!(including!both!geological!and!biological!samples)!

€ Sample!curation,!including!preparation!for!safe!Earth!return!(with!the!crew!or!via!separate!robotic!spacecraft)!

!

Have!you!demonstrated!(through!analysis!or!prototyping)!the!merits!of!one!or!more!approaches!to!create!an!innovative!solution!for!

providing!the!required!function!as!part!of!the!overall!focused!cis:lunar!design?!!

Have!you!examined!the!potential!for!these!same!functions!to!be!operated!in!conjunction!with!NASA’s!proposed!asteroid!redirect!mission!

where!the!facility!would!be!docked!to!the!asteroid!return!vehicle!to!facilitate!crewed!exploration!of!the!returned!asteroidal!material?!!

HUMAN%LUNAR%ACCESS%AND%INITIAL%EXPLORATION! Page%#%Have!you!successfully!demonstrated!a!new!technology!or!increased!robotic!capabilities!for!space!exploration,!tele:operated!from!a!crew:

tended!outpost!in!cis:lunar!space?!!!

Have!you!developed!an!innovative!concept!or!function!for!one!or!more!of!the!robotic!capabilities?!!(Select+all+that+apply)+€ Tele:operation!of!a!Lunar!surface!asset!!!!!!!!!!!!€!Free:flying!EVA!inspection!€ EVA!crew!assistant!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!€!IVA!crew!assistant!

!

Have!you!demonstrated!(through!analysis!or!prototyping)!the!merits!of!one!or!more!approaches!to!create!an!innovative!solution!for!

providing!the!required!function!as!part!of!the!overall!focused!cis:lunar!design?!!

Have!you!examined!the!potential!for!these!same!functions!to!be!operated!in!conjunction!with!NASA’s!proposed!asteroid!redirect!mission!

where!the!facility!would!be!docked!to!the!asteroid!return!vehicle!to!facilitate!crewed!exploration!of!the!returned!asteroidal!material?!!

!

Benjamin Mellman

1-6

Benjamin Mellman

1-6

Benjamin Mellman

2-5

Benjamin Mellman

6, 7, 9

Benjamin Mellman

8-10,

Benjamin Mellman

4,5, 9, 13-16

Benjamin Mellman

1-6

Benjamin Mellman

Benjamin Mellman

1-6

Benjamin Mellman

5,8,10

Benjamin Mellman

5,8,10

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

1-10

Benjamin Mellman

Benjamin Mellman

Benjamin Mellman

1-10

Benjamin Mellman

1-10

Benjamin Mellman

yes,1&2

Benjamin Mellman

7

Benjamin Mellman

yes, 1-6

Benjamin Mellman

yes, 1-6

Benjamin Mellman

yes

Benjamin Mellman

yes

Benjamin Mellman

yes

Benjamin Mellman

yes

Benjamin Mellman

*Irene Borillo Llorca *Rajarshi Chattopadhyay *Benjamin Mellman ...

Documents

Irene Borillo Llorca Rajarshi Chattopadhyay *Benjamin Mellman ...