Anthony J. Colozza

QinetiQ North America Corporation, Brook Park, Ohio

Pat George

Glenn Research Center, Cleveland, Ohio

Ronnie Gambrell

Johnson Research Center, Houston, Texas

Chris Chapman

Jacobs Technology, Inc., Houston, Texas

Overview of the Habitat Demonstration Unit

Power System Integration and Operation at

Desert RATS 2010

NASA/TM—2013-217861

June 2013
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Anthony J. Colozza

QinetiQ North America Corporation, Brook Park, Ohio

Pat George

Glenn Research Center, Cleveland, Ohio

Ronnie Gambrell

Johnson Research Center, Houston, Texas

Chris Chapman

Jacobs Technology, Inc., Houston, Texas

Overview of the Habitat Demonstration Unit

Power System Integration and Operation at

Desert RATS 2010

NASA/TM—2013-217861

June 2013

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
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Level of Review: This material has been technically reviewed by technical management. 
NASA/TM—2013-217861 iii 

Contents 

Abstract ......................................................................................................................................................... 1

1.0 Introduction and Background ................................................................................................................. 1

2.0 HDU Power System Summary ............................................................................................................... 3

3.0 Power System Operation at Desert RATS ............................................................................................ 13

4.0 Options for Future Development .......................................................................................................... 20

4.1 Power System for X-Hab Living Loft ........................................................................................... 20

4.2 Power Production Integration ........................................................................................................ 21

4.3 Construction of a 3 kW PV Mobile Power System ....................................................................... 21

4.4 Fuel Cell Power Source ................................................................................................................. 24

4.5 Induction Charging System ............................................................................................................ 25

5.0 Summary .............................................................................................................................................. 25

Appendix—Power Schematic for HDU Sections ....................................................................................... 27

NASA/TM—2013-217861 1 

Overview of the Habitat Demonstration Unit Power System 

Integration and Operation at Desert RATS 2010 

Anthony J. Colozza 

QinetiQ North America Corporation 

Brook Park, Ohio 44142 

Pat George 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Ronnie Gambrell 

National Aeronautics and Space Administration 

Johnson Research Center 

Houston, Texas 77058 

Chris Chapman 

Jacobs Technology, Inc. 

Houston, Texas 77058 

Abstract 

A habitat demonstration unit (HDU) was constructed at NASA Johnson Space Center (JSC) and 

designed by a multicenter NASA team led out of NASA Kennedy Space Center (KSC). The HDU was 

subsequently utilized at the 2010 Desert Research and Technology Studies (RATS) program held at the 

Black Point Lava Flow in Arizona. This report describes the power system design, installation and 

operation for the HDU. The requirements for the power system were to provide 120 VAC, 28 VDC, and 

120 VDC power to the various loads within the HDU. It also needed to be capable of providing power 

control and real-time operational data on the load’s power consumption. The power system had to be 

capable of operating off of a 3 phase 480 VAC generator as well as 2 solar photovoltaic (PV) power 

systems. The system operated well during the 2 week Desert RATS campaign and met all of the main 

goals of the system. The power system is being further developed to meet the future needs of the HDU 

and options for this further development are discussed. 

1.0 Introduction and Background 

The design and operation of a lunar habitat module, illustrated in Figure 1, requires the integration of 

a number of independent systems. These systems together provide an environment for astronauts to live 

and work on the lunar surface. The power system is a critical element in the overall habitat design; it must 

be capable of connecting to various outside power sources, distributing that power within the habitat 

module, and meeting the voltage and current requirements of the module’s internal equipment and 

systems. 

The habitat demonstration unit (HDU) is designed to look and operate similar to a habitat module on 

the lunar surface that will provide a realistic experience of lunar operations for the personnel and 

controllers. However, the HDU and its systems will not need to physically be capable of operating within 

the harsh lunar environment. The goal for the systems is to provide a functional capability and be 

functionally representative of what the lunar system would be like. 
NASA/TM—2013-217861 2 

The equipment installation within the HDU was broken down into 8 segments, listed as A through H. 

These segments are illustrated in Figure 2. Power was provided to each segment through a dedicated bank 

of outlets on the power distribution units (PDUs) installed within the HDU. Depending on the equipment 

installed in a given section, power conditioning was also supplied providing 28 and 120 VDC along with 

the 120 VAC. 
NASA/TM—2013-217861 3 

The goal of the power system design was to provide a controllable system that was operationally 

representative of what would be utilized in a lunar habitat module. The power system had to be capable of 

operating off of a number of different power sources, such as building supplied power, generator power 

and solar power. An additional goal in the system design was to demonstrate the interconnection and load 

sharing between the various power sources. This load sharing capability specifically applies to the 

connection of the PV power systems to jointly power the HDU. Combining the PV sources provides a 

“mini-grid” for distributing and supplying power to the loads within the HDU, which is representative of 

how a lunar power grid would be initially established. Lunar landing vehicles and other fixed surface 

assets would have power systems incorporated into them. Once the primary mission for these assets is 

completed, it would be advantageous to utilize these power sources to provide additional power to other 

nearby assets. Being able to sync and utilize the separated PV power systems for powering the HDU is a 

first step in demonstrating this desired capability. 

2.0 HDU Power System Summary 

The power system within the HDU consisted of a number of distribution, control and conditioning 

components, as listed in Table 1. 

TABLE 1.—POWER SYSTEM COMPONENT LIST 

Component Quantity Mass, 

kg 

Dimensions 

W, H, D, 

m 

120 VAC to 28 VDC power converter 2 17.2 0.25, 0.20, 0.10 

120 VAC to 120 VDC power converter 2 17.2 0.25, 0.20, 0.10 

Power Distribution Unit (PDU) 3 9 0.11, 0.44, 0.09 

Power supply unit 1 15 0.45, 0.25, 0.15 

120 VAC outlets (outside) 2 1 0.10, 0.10, 0.08 

120 VAC outlets (inside) 2 1 0.10, 0.10, 0.08 

Junction box 1 7 0.51, 0.41, 0.15 

Primary switch 1 14 0.46, 0.25, 0.15 

Primary distribution wiring harness 1 5.5 NA 

Secondary distribution wiring harness 1 23 NA 

Terminal strip junction boxes 4 4 NA 

Grounding straps 16 32 NA 

220 to 120 VAC transformer 1 80 0.25, 0.28, 0.38 

The power distribution units (PDU) provided power distribution and control within the HDU. The 

PDUs were installed beneath the flooring of the HDU and connected to the outside power source through 

a main junction box. 

The PDUs consisted of three APC (model AP7902, shown in Fig. 3) Switched Rack Mount 3.6 kVA 

units with L5-30 input power connector and standard 120 VAC outlet connectors. Each PDU has a 

maximum 30-amp output capacity with 16 outlets controllable in two banks of 8. Communication to the 

PDU is over an Ethernet connection. Each outlet of the PDU is capable of being commanded on or off 

remotely or on a schedule through the communication line. Each bank of the PDU is circuit breaker 

protected with a 20 amp breaker switch. Data can be gathered on the PDU operation such as: 

 Overall current versus Time, low, near-high and high thresholds 

 Bank A (outlets 1 to 8) Overall Current versus Time; low, near-high and high thresholds 

 Bank B (outlets 9 to 16) Overall Current versus Time; low, near-high and high thresholds 

To provide DC power, required by some loads, 2 types of AC to DC converters were utilized. These 

converters were powered through the PDUs, which also provided control over their operation. These 

converters consisted of two Astron 18A 28VDC rack mount power supplies, ZAS-LSRM-18A 28 VDC, 

as shown in Figure 4 and two Sorensen 8A variable output rack mount power supplies, models DCS150-7 

and DCS150-7E, shown in Figure 5. The Sorensen power supplies were capable of output voltages up to 

150 VDC, however for this application they were set and locked at 120 VDC output. 
NASA/TM—2013-217861 4 
NASA/TM—2013-217861 5 

The power conditioning and control equipment was mounted below the floor level in the HDU. 

Cooling air was circulated in the space beneath the floor to maintain the electronics at their required 

operational temperature. The installation locations for this equipment are illustrated in Figure 6 and the 

actual installations are shown in Figures 7 and 8. 
NASA/TM—2013-217861 6 

Junction boxes, as shown in Figure 9, contain terminal strips that were used to connect the loads to 

the DC power supplies. These junction boxes provided a single connection to the power supply and 

multiple outputs for the various loads. 
NASA/TM—2013-217861 7 

A single input was provided from the external power sources to the interior of the HDU. To connect 

the multiple PDUs to the single power input, junction boxes were used as shown in Figure 10. Two 

separate junction boxes were utilized, one to connect the PDUs to the diesel powered generator and the 

second to connect them to the solar powered systems. 

The sections of the HDU, shown in Figure 2, in which the power system components were mounted 

are listed in Table 2. All of the lights throughout the HDU were connected to the 120 VDC converter 

located in section B. 

TABLE 2.—LOCATION OF THE POWER CONDITIONING COMPONENTS WITHIN THE HDU 

A None 

B  PDU 

 120 VDC Power Converter (with separate terminal box 

 28 VDC Power Converter (with separate terminal box) 

C None 

D None 

E None 

F  PDU Junction Box (for connecting the outside power to the individual PDUs) 

 PDU 

 120 VDC Power Converter (with separate terminal box 

 28 VDC Power Converter (with separate terminal box) 

G None 

H  PDU 
NASA/TM—2013-217861 8 

The PDUs were tested prior to installation into the HDU to evaluate their operation and controls. The 

configuration used for this testing is illustrated in Figure 11. Building supplied power, limited to 20 A, 

was used during the testing. To insure that the current draw for this evaluation testing was not beyond the 

capacity of the outlet, only one bank on the PDU was utilized. Each bank of outlets on the PDU is circuit 

breaker limited to 20 A maximum output. There were no problems or operational concerns encountered 

with the PDU testing. The communication and control to the PDU worked well and the internal circuit 

breaker protection on the PDUs functioned properly. 

The loads connected to the PDUs were distributed among the three installed units (B, F, H). 

Provisions were made so that an additional PDU could be installed in section D. The breakdown of the 

loads connected to each PDU is given in Table 3. 

TABLE 3.—PDU LOAD SUMMARY 

PDU B PDU F PDU H 

1 120 VDC Converter 120 VDC Converter Internal 

Overhead Lights 

GeoLab 1 

2 28 VDC Converter Powering 

External Spotlights on Sections 

B,D,F and H 

28 VDC Converter; Veggie, 

External Airlock Light 

Internal Outlets in Sections B,D,F and H 

3 cRIO Control System Electro Dynamic System 

4 Not Used Med Ops Not Used 

5 AirLock: Including, Winch, A/C 

Unit, Exhaust Fan, Battery Chargers, 

Web Cams, Sensors, Vacuum, 

Internal Lights. 

Not Used Not Used 

6 HIMS Not Used Not Used 

7 Not Used Not Used Not Used 

8 Not Used Not Used Not Used 

9 General Workstation (Power Strips) Avionic Rack #2 (UPS) GeoLab-2 

10 General Workstation (Power Strips) External Outlets in Sections 

A,C,E & G 

Four Smoke/CO Monitors 

11 Not Used External Outlets for top floor in 

Sections F & B 

WebServer 

12 Overhead Light Comm System (CSA) Not Used 

13 Rope Light Not Used Not Used 

14 Not Used Not Used Not Used 

15 Not Used Not Used Not Used 

16 Not Used Not Used Not Used 
NASA/TM—2013-217861 9 

In addition to supplying power to the interior of the HDU, a number of power outlets and lights were 

placed on the outside for powering external devices and nighttime lighting. The locations of these outlets 

and lights are illustrated in Figure 12. 

Power was supplied to the HDU from different sources depending on its operating location. This is 

illustrated in Figure 13. The available external power sources varied depending on the operational 

location of the HDU. The three operational locations included, within building 220 and the Rock Yard at 

JSC, at the Desert RATS remote test site and at the Desert RATS base camp. The detailed layout of the 

power system and external power source for each of these locations is shown in Figures 14 to 16, 

respectively. The power system was designed to accommodate the different power sources available at 

the different operational locations. 
NASA/TM—2013-217861 10 
NASA/TM—2013-217861 11 
NASA/TM—2013-217861 12 

The external power sources were connected to the HDU power system through various connectors 

located on a panel on the outside of the HDU as shown in Figure 17. A power distribution cart was used 

to connect the HDU to the 480 VAC 3 phase external power generator. This distribution cart shown in 

Figure 18 consisted of 480 VAC 3 phase to 120 VAC single-phase transformer and three switches. The 

first switch was used to connect and disconnect the generator from the distribution cart. The other two 

switches were used for connecting and disconnecting the power from the HDU and heat pump. 
NASA/TM—2013-217861 13 

The solar power systems were connected to the HDU through a separate junction box, shown in 

Figure 19. This junction box consisted of four L5-30 male ports. The junction box combined the power 

from the PV sources to a single line that was fed to the main 100-amp breaker switch and into the HDU. 

The power output from the solar sources was 120 VAC. The power waveform was synced at the PV 

sources therefore no active syncing was needed at the HDU. 

3.0 Power System Operation at Desert RATS 

The 2010 Desert Research and Technology Studies (RATS) campaign took place at the Black Point 

Lava Flow outside of Flagstaff Arizona. The Black Point Lava Flow terrain provided an environment 

geologically similar to the lunar surface. The Desert RATS program is conducted annually, its goal being 

to provide analog testing of different elements of a mission operating together in an environment similar 

to that of an actual mission to evaluate how the different elements work together. The HDU operation was 

one part of the overall Desert RATS program. 

The HDU was operated at 2 locations within the Black Point Lava Flow, the base camp location and 

the SP crater location. Both are shown in Figure 20. 

The power system operation at Desert RATS consisted of two main areas, the power components and 

distribution within the HDU and the external power sources, which supplied power to the HDU. A 

WhisperWatt 125 kW diesel generator, (shown in Fig. 21) powered the HDU for the majority of time it 

was operating. The generator provided 3 phase 480 VAC power to both the air-conditioning unit and the 

main transformer which converted it to single phase 120 VAC which was utilized within the HDU. The 

diesel generator was used as the sole power source while the HDU was at the SP mountain location, 

shown in Figure 22. 
NASA/TM—2013-217861 14 
NASA/TM—2013-217861 15 
NASA/TM—2013-217861 16 

While at the base camp location, the diesel generator was supplemented by the two solar photovoltaic 

power systems shown in Figure 23. These systems consisted of the GSW-7000 photovoltaic and wind 

based power system from Green Trail Energy and a 1 kW solar test-bed trailer from NASA Glenn 

Research Center. These systems provided 120 VAC power to the HDU for daytime operations at the base 

camp location. The GSW-7000 power system can provide up to 4.5 kW of solar power as well as up to 

2.4 kW of wind power. It has a battery storage capacity of 1500 A-hrs. The GRC power system can 

provide up to 1.1 kW of PV power and has a battery storage capacity of 296 A-hrs. 

The GRC 1 kW mobile PV power system is a stand-alone power system capable of providing 

120 VAC, 240 VAC, and 48 VDC power to nearby loads through a number of standard cable connector 

ports. The photovoltaic array consists of 16 Seimans M55 solar panels rated at 55 W output and 

4 Kyocera 5KC50T 50 W solar panels. The panel output ratings are based on 1000 W/m2

 incident solar 

radiation. A battery bank consisting of four 74 A-hr deep discharge lead acid gel-cell batteries is used to 

store energy as well as regulate the voltage to the inverter. The batteries are charged from the array 

through an Outback MX60 battery charge controller. This battery charge controller has an array peak 

power tracking capability to maximize the output of the solar array. An Outback Grit-Tie 3.6 kW inverter, 

model GVFX3648, is used to provide 120 VAC output to the loads. In addition to the 120 VAC output a 

transformer is utilized to provide a 220 VAC output. A diagram of the system components is shown in 

Figure 24. 

The grid tie inverter was used to sync the output of the GSW-7000 to the output of the GRC power 

system. This was accomplished by taking a 120 VAC output line from the GSW-7000 inverter and 

connecting it to the input grid power terminals for the Outback inverter. This enabled the Outback 

inverter to see the GSW-7000 as the gird signal and match is output frequency and phase. 
NASA/TM—2013-217861 17 

Once synced, the output power lines from both PV power systems were connected to the HDU’s 

junction box, shown in Figure 19, and provided supplemental power to the internal components of the 

HDU. The diesel generator was not synced to the PV systems and therefore could not be used to power 

items connected to the PV sources. While the PV sources were operational the diesel generator was 

utilized to only run the air conditioning system for the HDU. 

The two PV power systems operated well together and provided seamless power to the loads within 

the HDU. The load sharing between the systems was successful. Initially the GSW-7000 was powering 

the entire load and the GRC system was operating in standby. The output of the systems then shifted and 

the GRC system provided the majority of the power up to the output of the PV array and the GSW-7000 

supplemented this to accommodate the total demand. This initial power output was approximately 750 W 

from the GRC system and 300 W from the GSW-7000. Throughout the day, as the sun elevation angle 

diminished, the GRC system array output would decrease and the GSW-7000 would pick up more of the 

load. The load sharing of the systems provided a demonstration of how power systems from separate 

vehicles or systems could potentially be gridded together to provide a power source infrastructure on the 

lunar surface. 

Data was also taken on the power draw from each of the PDUs during operation. The power 

consumption from each of the PDUs is shown in Figures 25 to 28 for a 2-day period of operation. 

Figure 25 shows the total current draw from each PDU over that period of time. From that figure it can be 

seen that the total load on each PDU differed with PDU F carrying a significantly higher load over the 

time period then the other two PDU. The power loads on all 3 PDUs was fairly consistent with some step 

up and down throughout the course of the 2-day period. There were some power spikes, the largest of 

which occurred on PDU F in which the output current increased from approximately 2.5 to 10.5 A for a 

short period of time. 

The subsequent Figures 26 to 28 show the individual bank current draw from each of the PDUs over 

the same time period. These curves show how the load power was distributed between the two banks on 

each of the PDUs. For the most part, the load on each PDU was fairly equally distributed between the two 

banks of each PDU. 
NASA/TM—2013-217861 18 
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NASA/TM—2013-217861 20 

4.0 Options for Future Development 

The future development of the HDU power system will be focused on meeting any additional power 

needs of the HDU as well as incorporating additional types of power sources that are representative of the 

systems that would be utilized in a space application. 

4.1 Power System for X-Hab Living Loft 

The near term development of the HDU calls for an expansion above the main level to provide living 

quarters for crew. A Power System to accommodate this loft area will include the following additional 

items: 

 Eight 2-outlet plugs will be incorporated into the floor of the loft. These will be symmetrically 

distributed along the floor and located near the outer wall of the loft. A 28 VDC power junction box 

will also be supplied to provide power to test and data equipment. This is illustrated in Figure 29. 

 An additional PDU will be added to accommodate the power requirements of the loft. This PDU can 

provide a total of 30 A at 120 VAC in two banks of 15 A each. One of these banks will be dedicated 

to the loft area and connected to the 8 outlets installed in the loft floor. 

 The other bank will be available to the main Hab or could potentially also be utilized to power the loft 

if needed. Using this second bank for powering the loft would require running an additional power 

line from the PDU to the loft and connecting some (half) of the plugs to this second power line. 

 A separate power line from the generator will power the additional PDU. This will require a 

transformer, junction box and switch. This arrangement will be identical to the one presently installed 

that provides power to the existing 3 PDUs within the HDU. The 4th PDU will be powered through a 

separate input line. The external power input and conditioning components will be duplicated to 

provide power to the 4th PDU. Duplicating the existing power connection components has 2 main 

benefits. It enables the existing power input infrastructure to remain unchanged and it will provide the 

capacity to add 2 additional PDUs for future expansion. 

 A second PV source junction boxes and switch will also be added to provide PV power to the 4th 

(and potentially 2 additional PDUs). 

These items are illustrated in Figure 30. 

 
NASA/TM—2013-217861 21 

4.2 Power Production Integration 

As the development of the HDU system continues, the integration of power production systems and 

components will be necessary. One concept in the incorporation and integration of additional power 

sources is to include a fuel cell power source. An approach to this is to integrate the fuel cell system along 

with a deployable solar array onto the roof of the HDU as shown in Figure 31. This concept provides an 

integrated power production and storage system that is part of the HDU. 

Integrating the power production system into the HDU is a logical progression in the development of 

the HDU as a complete standalone habitat. As the HDU system architecture grows and becomes closer to 

space hardware in its configuration, the integration of a power generation capability will be an important 

aspect of the design. As an example, the growth and integration of a multiunit habitat system for a lunar 

surface application is illustrated Figure 32. The power production integration is a longer-term goal of the 

overall power system architecture development. Many incremental steps will be necessary before a 

system, as shown in Figures 31 and 32 is produced. However, the main power production and 

conditioning components of this type of system can be developed as stand-alone items and utilized in near 

term demonstrations towards the goal of ultimately developing a fully integrated system. 

4.3 Construction of a 3 kW PV Mobile Power System 

The objective is to provide a second PV based power system with greater capacity than the 1 kW 

system presently used. A 3 kW system can be constructed with the ability to be used as a stand-alone 

system or connected to the 1 kW system, allowing them to function together as a single power source. 

The 3 kW mobile power system will be constructed in a similar manner as the 1 kW system. The main 

difference is in the structural layout that will need to accommodate the larger solar array. Some of the 

components for the 3 kW system are shown in Figure 33. 

The 3 kW mobile PV power system would be capable of providing approximately 2400 W of output 

power continuously from dawn to dusk at the Black Point Lava Flow location during September, as 

shown in Figure 34. The system would also be capable of syncing to the 1 kW through the capabilities of 

the Outback inverter. Once synced, the output of both power systems can be combined within a junction 

box to provide a single output power connection enabling both systems to provide power to the HDU 

simultaneously. This is illustrated in the component layout shown in Figure 35.
NASA/TM—2013-217861 22 
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NASA/TM—2013-217861 24 

4.4 Fuel Cell Power Source 

A mobile fuel cell platform can be constructed to provide auxiliary and nighttime power to the HDU 

through the same interface as the PV systems. The fuel cell systems can be built up on one or more small 

trailers. Each system would include four Ballard Nexa hydrogen-air fuel cells, shown in Figure 36. Each 

of these fuel cells can provide 1.2 kW of power for a total of 4.8 kW per mobile system. The fuel cells 

would be wired to provide a 48 VDC output which would enable them to operate with the same inverters 

as the PV systems. To accomplish this task, 2 fuel cells would be connected in parallel and 2 sets of these 

groupings would be connected in series. 

To provide fuel for the fuel cells, hydrogen gas would need to be stored on tanks located on the 

mobile platform. The tanks can be constructed of carbon composite with an aluminum liner to minimize 

weight. The hydrogen gas can be supplied from either a stored hydrogen source that would need to be 

located near the operational location or it can be produced on site through the use of an electrolyzer. The 

electrolyzer option would provide a demonstration of the operation of an additional critical power system 

component. 

An available Proton HoGen 10 electrolyzer, shown in Figure 37, can be utilized for producing high 

purity hydrogen gas. The electrolyzer is capable of providing 200-psi hydrogen at a rate of 10 scf/hr. It is 

also capable of producing 200-psi oxygen. If higher-pressure hydrogen gas is desired the storage pressure 

can be increased beyond the 200 psi supplied by the electrolyzer with the use of a hydrogen compressor. 

The electrolyzer along with storage tanks and the associated gas handling systems, shown in Figure 38, 

can be mounted onto a small trailer to provide a mobile hydrogen source for use in refilling tanks for the 

fuel cell system. 
NASA/TM—2013-217861 25 

4.5 Induction Charging System 

The implementation of an induction charging system can provide a connection-free method for 

charging various devices and systems from the HDU power system. This type of charging system can be 

utilized within the HDU to provide easy charging for electronics, as shown in Figure 39. It can also be 

utilized as a means of recharging the batteries within a spacesuit without having to bring the spacesuit into 

the HDU. The spacesuit can be left on the outside of the HDU or within the airlock against a specially 

designed charging pad. The system would automatically charge the batteries within the suit to prepare it for 

the next EVA. It can also be used as a means of charging a rover. The rover could drive over a specially 

designed charging pad that would electrically couple to the rover and provide charging to the battery. 

5.0 Summary 

The operation of the HDU power system during the 2010 Desert RATS was successful. The power 

system met the various loads power requirements and provided continuous operation of the loads 

throughout the testing. The main power source for the testing was the 3-phase 480 generators. However, 

2 photovoltaic systems were also utilized during the testing as a means of demonstrating a more spacelike power source. The power system design allowed both the generator and the PV sources to provide 

power to the loads. This was accomplished with minimal interruption to the loads. The 2 PV systems 

were successfully synchronized so that their output could be combined and fed to the HDU. However, the 

PV systems were not capable of synchronizing with the generator. Therefore the power from the PV 

systems was used to provide power to a single PDU, while the generator provided power to the remaining 

2 PDUs. This kept both the generator and PV systems isolated from each other during operation. The 

power system will be further developed for the next generation HDU testing. This development will 

include increasing the capacity of the system and providing an easier and more standardized means of 

connecting and conditioning power from various sources. 

Appendix—Power Schematic for HDU Sections 

Section A 

Figure 40.—Section A power system schematic. 

NASA/TM—2013-217861 27
Section B 

Figure 41.—Section B power system schematic. 

NASA/TM—2013-217861 28
Section C 

Figure 42.—Section C power system schematic. 

NASA/TM—2013-217861 29
Section D 

Figure 43.—Section D power system schematic. 

NASA/TM—2013-217861 30
Section E 

Figure 44.—Section E power system schematic. 

NASA/TM—2013-217861 31
Section F 

Figure 45.—Section F power system schematic. 

NASA/TM—2013-217861 32
Section G 

Figure 46.—Section G power system schematic. 

NASA/TM—2013-217861 33
Section H 

Figure 47.—Section H power system schematic. 

NASA/TM—2013-217861 34

REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188 

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PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 

1. REPORT DATE (DD-MM-YYYY)

01-06-2013 

2. REPORT TYPE

Technical Memorandum 

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Overview of the Habitat Demonstration Unit Power System Integration and Operation at 

Desert RATS 2010 

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

Colozza, Anthony, J.; George, Pat; Gambrell, Ronnie; Chapman, Chris 

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

WBS 342806.06.03.03 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration 

John H. Glenn Research Center at Lewis Field 

Cleveland, Ohio 44135-3191 

8. PERFORMING ORGANIZATION

 REPORT NUMBER

E-18654 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration 

Washington, DC 20546-0001 

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NASA 

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NASA/TM-2013-217861 

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Unclassified-Unlimited 

Subject Categories: 20 and 18 

Available electronically at http://www.sti.nasa.gov 

This publication is available from the NASA Center for AeroSpace Information, 443-757-5802

13. SUPPLEMENTARY NOTES

14. ABSTRACT

A habitat demonstration unit (HDU) was constructed at NASA Johnson Space Center (JSC) and designed by a multicenter NASA team led 

out of NASA Kennedy Space Center (KSC). The HDU was subsequently utilized at the 2010 Desert Research and Technology Studies 

(RATS) program held at the Black Point Lava Flow in Arizona. This report describes the power system design, installation and operation for 

the HDU. The requirements for the power system were to provide 120 VAC, 28 VDC, and 120 VDC power to the various loads within the 

HDU. It also needed to be capable of providing power control and real-time operational data on the load’s power consumption. The power 

system had to be capable of operating off of a 3 phase 480 VAC generator as well as 2 solar photovoltaic (PV) power systems. The system 

operated well during the 2 week Desert RATS campaign and met all of the main goals of the system. The power system is being further 

developed to meet the future needs of the HDU and options for this further development are discussed.

15. SUBJECT TERMS

Power; Electric power; Power conditioning; Power converters; Solar generators; Lunar exploration; habitats 

16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

 ABSTRACT

UU 

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44 

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