Greenhab Report – January 15th

GreenHab Report

Hernán David Mateus Jiménez

15/01/2018

Environmental control:

Ambient with door opening

Shade cloth on

Working Hour: 6:15
Inside temp at working hour: 16° C
Outside temp during working hours: 2° C
Inside temperature high: 25° C
Inside temperature low: 15° C
Inside humidity: 73 %RH

Inside humidity high: 67 %RH
Inside humidity low: 23 %RH

Hours of supplemental light:

For the crops 05:00 to 11:59 PM

Changes to crops: The cucumber plants are a little wilted today

Daily water usage for crops: 8 gallons

Time(s) of watering for crops: 45 min

Research observations: The research has not started

Changes to research plants: The research has not started

Aquaponics: Not Functional

Narrative: Today I have had a great day, my first EVA on Mars, where I could test the necessary tools to collect Martian soil in my next EVA, after it, I did not realize that the temperature decrease, so I forgot to close the door at the afternoon, fortunately Atila did it. Also I had to repair some pieces of my project that were broken during the trip to Mars, so today I could not finish the assembly of the lysimeter.

Because of the fact that the source of water close to the greenhab is not working, I am spending a lot of time filling the watering can in the kitchen of the hab.

I hope to finish the assembly of the lysimeter and start the quinoa crop over it with the soil that we will get tomorrow at the EVA.

Sol Summary – January 15th

Crew 187 Sol 3 Summary Report 15JAN2018

Sol 3

Summary Title: Spaceman

Author’s name: Cynthia Fuertes Panizo

Mission Status: All nominal

Sol Activity Summary:

Mission Support,

Greetings from Mars!!! One more day in the red planet, it’s
breathtaking how every Martian has been integrated. At 07:20 we were together at the lower deck to do some relaxing exercises in the lead of by David, who also cleaned the Hab with Luis. At 08:00, we ate breakfast together while we did the briefing.

The day looked promising because today we will be our first EVAs. We wanted to assets the performance of the crew with the suits
operations, so the routine of each EVA was to walk over even terrain, then drive using ATVs and Curiosity; and finally we made summit in Overlook Reach. The first group of the EVA was conformed by Atila, Oscar Danton and I; their time of donning started at 11:00 until 11:30, in that moment the real adventure began and lasted until 13:00. Later, in the habitat they gave advices to the following group of EVA. The second group was conformed by Atila, Tania, Luis and David. Their expedition lasted until 15:30. Both EVA was led by Atila. After each EVA, the crew started to exchange their feelings about to be in a real expedition, that feeling of been a Martian is unique!

By the way, between the 2 EVAs, at 13:20, Tania and I, went to the Musk Observatory just to check the status.

As lunch, Oscar cooked rice with cheese and meal, it was a delicious lunch! Later, Shannon visited us to explain about the map on Mars. She suggested us to visit wonderful places like Copernicus highway, Lith canyon, Tank wash, Candor Chasma, and so on… We plan to visit those places, thanks for your advice!

Today we are going to have our first movie night in Mars, we are so excited for that!

Look Ahead Plan:

There are two main things that the crew are waiting for tomorrow, do an EVA to collect some examples for Atila and David’s experiments. In addition, the Musk Solar Observatory will be used… Can you imagine it? Look the sun from Mars!!!

Anomalies in work:

The commander room’s door was locked from inside. David and Atila worked together to open it again! Now we know that a locksmith is a profession in Mars.

Weather: Temperature: 2°C, Fair weather, Winds speed: NNE 6 MPH, Humidity 60%, Barometer 30.31in

Crew Physical Status: Healthy

Reports to be filed: Sol Summary, GeenHab Report, Operations Report, EVA Request, EVA Report, Astronomy Report, Journalist Report and HSO Report.

Support Requested: None.

EVA Report – January 15th

Purpose of EVA: Space Suit activity recognition and Assessment of in-suit performance

Participants:

EVA 1: Atila, Danton, Oscar, Cynthia

EVA 2: Atila, Luis, David, Tania

Narrative: The crew conducted the first EVA set of activities today, and it was a huge success, whit all the objectives completed. The main goal of the EVA was to get all the crewmembers a first approach to external operations, and to test the main tools we would be using from now on, on each of the projects. The EVA was designed to also test the performance of the crewmembers with the gear on, to plan better the next EVAs, and assignments. Both crews performed the same routine, with small variations. The routine began by the donning of the suits, proceeding to enter the airlock, 5 minute depressurization, and going out in front of the hab. From there, the group took a straight route until the south of Marble Ritual, try the quadcopter operation, and the shovels for sampling. Upon return to the hab area, the crew left some of the equipment back and mounted the vehicles, 3 ATVs and the Curiosity Rover. It is important to clear that the requested Rover was Deimos, but the designated driver in EVA 1, Danton, would not fit inside of it, requiring the use of the one without safety cage. In order to keep the same protocols, EVA 2 used the same Rover. The next route was traversed by vehicle and took the crew to Pooh’s Corner, where a second brief walk was undertaken, towards a small mound on the East of Cow Dung Road. Afterwards the crew returned to the vicinity of the hab to perform the last test, which consisted of making summit of Overlook Ridge. The crew then returned to the airlock, sustained repressurization, and upon entry to the hab, proceeded to doffing protocols.

Each crewmember was interviewed upon finalization of the doffing on qualitative, and quantitative factors, as well as general comments on the performance of themselves on the suit. Further comment on this will be posted on the final report.

Oscar Ojeda

EVA Officer – Crew 187

Operations Report – January 14th

Operations Report

Subject Line: Crew 187 Operations Report 14JAN2018

Crew 187 Operations Report 14012018

SOL: 2

Name of person filing report: L. Diaz

Non-nominal systems: None

Notes on non-nominal systems: Generator system limping along with a now-nominal routine.

Generator (hours run): 15h 50min

Generator turned off, charging battery at 9:45 am

Generator turned on at 18:36 pm

Solar— SOC

@ 11:04: 100%

@ 18:36: 53%

Diesel: 50%

Propane: 27%

Ethanol Free Gasoline (5 Gallon containers for ATV): XX Gallons

Water (trailer): – Gallons

Water (static): – Gallons

Trailer to Static Pump used: No

Water (loft) – Static to Loft Pump used: Yes

Water Meter: – Gallons

Toilet tank emptied: No

ATVs Used: (Honda, 350.1, 350.2, 350.3)

Oil Added? No

ATV Fuel Used: – Gallons

# Hours the ATVs were used today: 0.5 hours

Notes on ATVs: ATVs were nominal.

Deimos rover used: No

Hours: –

Beginning charge: 100%

Ending charge:

Currently charging: No

Sojourner rover used: Assigned to director only.

Hours: Director discretional hours

Beginning charge:

Ending charge:

Currently charging: Maybe

Spirit rover used: Si

Hours: –

Beginning charge: 100%

Ending charge:

Currently charging: Yes

Opportunity rover used: No

Hours: –

Beginning charge:

Ending charge:

Currently charging: No

Curiosity rover used: Yes

Hours: –

Beginning charge: 100%

Ending charge:

Currently charging: Yes

HabCar used and why, where? No

General notes and comments: Today was just a training day. I didn’t have the opportunity to check the hours from the rover’s, fuel and the level of water.

Summary of internet: All nominal

Summary of suits and radios: All nominal but I found that the ventilation system of the regular suit #5 is not working.

Summary of Hab operations: All nominal

Summary of GreenHab operations: All nominal

Summary of ScienceDome operations: All nominal

Summary of RAM operations: Not Operational

Summary of health and safety issues: Crew is Healthy

Questions, concerns and requests to Mission Support: As I said in the Summary of suits, the ventilation system of the regular suit #5 is not working, can I try to fix it tomorrow?

Journalist Report – January 14th

[Sol 02] [Interstellar]

The day began with the farewell and boarding of the Crew 186 in their spaceship to our planet and old sweet home, Earth. From this dawn we became Martians coming from distant lands between each other: Peru, Colombia and Mexico, but in this desert planet we only represent the Earth and some of its forms of life.

We grew up thinking that astronauts only eat tubes of dehydrated food but on this trip to Mars we discovered that macaroni with cheese, tuna and chocolate cookies will also be part of our diet. Important: We receive food from the Russian Space Food Laboratory, thank you.

In our arrival to the habitat we have settled in our small rooms that barely reach a few square meters that daily will see us sleeping while thousands of stars shine in the sky and a body similar to the satellite of the Earth rises between the Martian mountains illuminating together with the Sun our mornings.

Today the habitat director showed us every corner of the station and the operation. Also we use of Spirit, Curiosity, Deimos, the Red ATV and the three Blue 350 vehicles to explore some roads and nearby lands. We also were showed the Science Lab and the solar observatory for in the next few days be able to use them.

When we returned to the habitat we made our first pressurization test where for five minutes we locked ourselves in the airlock to discuss which songs will be the ones that relax us during the minutes that the process will take. Apparently telling jokes will also be allowed.

Finally the night fell and after writing the reports and planning the activities of the next day we will sit down to eat pancakes and food experiments as well as continue knowing the pleasures and expectations of each crew member.

We hope to start our first EVA tomorrow morning and use our suits along with the helmets to train but not without first performing a morning exercise routine and taking a nutritious breakfast.

LATAM II will continue to inform.

Tania Robles, MDRS Crew 187 Journalist

GreenHab Report – January 14th

GreenHab Report

Hernán David Mateus Jiménez

14/01/2018

Environmental control:

Ambient with door opening

Heating

Shade cloth on

Working Hour: 6:30
Inside temp at working hour: 17° C
Outside temp during working hours: 0° C
Inside temperature high: 30° C
Inside temperature low: 15 C
Inside humidity: 75 %RH

Inside humidity high: 75 %RH
Inside humidity low: 21 %RH

Hours of supplemental light:

For the crops 05:00 to 11:59 PM

Changes to crops: No changes

Daily water usage for crops: 8 gallons

Time(s) of watering for crops: 15 min

Research observations: The research has not started

Changes to research plants: The research has not started

Aquaponics: Not Functional

Narrative: Today I have started as the new Greenhab Officer in the station, I hope to continue maintaining it as beautiful as now. Thank you Mark.

During my first day, I have divided the crops in 8 regions in order to compare each day the changes using picture

Tomorrow I will start to assemble the lisimiter in order to start to measure evapotranspiration in the crop of quinoa that Atila plant at the Saturday. Also, I will check the inventory of the crops that Mark shared with me during the training.

Today during the irrigation, I realized that one of the sprinklers is broken.

Sol Summary – January 14th

Crew 187 Sol 2 Summary Report 14JAN2018

Sol 2

Summary Title: Across the Universe

Author’s name: Cynthia Fuertes Panizo

Mission Status: All nominal

Sol Activity Summary:

Mission Support,

Greetings from Mars!!! After a very long journey we finally arrived to Mars yesterday, where we spent some quality time with the previous crew. Today is our first day managing everything by ourselves, we awoke early at 06:30 for the farewell of crew 186. We are so excited to be in Mars, we started our day talking about the rules and the schedules that we are going to follow during this awesome experience. Then we settle down in our home. One of the surprise of the day was the moment when we opened the food suppliers and found food from Russian Space Food Laboratory… Thank you so much for it!

For lunch Oscar cooked us tuna salad and potato… our first lunch in Mars!!! By the afternoon, Dr. Ruppert explain us in detail the protocols that we have to follow and we had our EVA’s training with her. Later, we started to plan the following EVAs.

Look Ahead Plan:

Dr. Ruppert will tell us the final part of the protocols of the simulation in the morning. Later we are going to do 2 EVAs in order to assets the performance of the crew with in suits operations. It’s almost some hours more and we are going to know the feeling of walking and be a part of expedition in Mars.

Anomalies in work:

We suspect that there is a leak in the toilet. The water level’s start to increasing little by little but then it works normal again. We hope it continuing working in a good way.

Weather: Temperature: 4°C, Fair weather, Winds calm, Humidity 60%, Barometer 30.35 inHg

Crew Physical Status: Healthy

Reports to be filed: Sol Summary, Operations Report, Journalist Report, Greenhab Report, EVA Request

Support Requested: Mission Support, please add my email to the e-list of MDRS Mission Support.

Science Report – January 13th

MDRS – Crew 186 – Final Geology Report

Research Project and Goals

The need to reduce payload mass for future space exploration is imperative, especially for long-term missions. Experts in the field or space exploration have been working for years on concepts of In-Situ Resource Utilization (ISRU). The idea of finding, collecting, processing, and using materials found at the destination requires various steps: we need to determine what materials are present and what is their abundance, accessibility, and usability; we also need to figure out what are the best ways to collect them; finally, based on the materials and their properties, we can decide how to process and use them. The simplest ISRU designs propose production of water, oxygen, and propellant [Sanders and Duke,
2005; Cuadros and Michalski, 2013]. However, establishment of bases on Mars will probably require the use of in-situ construction materials and metals, which must be easily accessible [Cooper, 2002; Curreri and Criswell, 1999;
Muscatello and Santiago-Maldonado, 2012; Sacksteder and Sanders, 2007; Wan et
al., 2015]. Identifying appropriate locations, with an adequate amount of resources will be a major factor for the selection of human landing sites, together with the scientific importance of the site [Horgan et al., 2013].

The goal of this project has been to test the use of remote sensing (performed in various locations) to support In-Situ Resource Utilization. Assessment of mineralogy and temperature readings – via remote sensing – has been performed to provide information about material abundance, water content and thermal inertia. The latter will be correlated to particle size and cohesiveness of the material, which in turn suggests the most appropriate tools to effectively collect the material for processing. Simple collection tools including rock hammers, spoons, and trowels have been evaluated in terms of ease of use, and efficacy of collection of the material, based on the physical properties of the material.

The MDRS region, in the Colorado Plateaus, is a good Mars analog, especially in the areas pertinent to the middle Jurassic Entrada Sandstone, the middle and and late Jurassic Morrison Formation, and the Dakota Sandstone. These areas exhibit mudstones and sandstones mainly composed of clays (montmorillonite, illite, and kaolinite, often coated with hematite), strata of paleo-gypsum and other sulfates, and recent evaporites. Most of those minerals are present close to regions of geological interest on Mars, and are dug on Earth for construction and other purposes.

Figure 1. Geology of the MDRS area

EVAs, samples, and results

Six geologic EVAs have been performed by the crew, visiting the following regions: URC North Site, area East of Greenstone Road, and The Moons (Morrison Formation and Dakota Sandstone); “Boilermaker Canyon”, previously unexplored by MDRS crews (Entrada Sandstone and lower Morrison Formation); Skyline Rim (Mancos Shale). The crew geologist and the rest of the crew collected a variety of samples in these location, and analyzed them with a “PANalytical QualitySpec TREK” portable spectrometer. The 86 Visible and Near Infrared (VNIR) spectra gave information about the mineralogy of the samples, and will be used to assess water content in the various locations. The geologist also measured temperature of rocks and soil at different depths and in different conditions, in replacement of measurements that were supposed to be taken with a thermal camera, which was not received in time for the mission. These measurements will be used after the end of the mission to determine the correlation between thermal inertia and physical properties of the material, such as cohesiveness and bulk size. The geologist used a rock hammer and a trowel to simulate collection of different material, under simulated Martian conditions for what concerns EVA suits and bulky gloves.

The EVAs brought the analog astronauts through diverse fields, ranging from plains covered in clays and characterized by salt deposits to deep canyons where million of years of strata are exposed. All the types of terrains are found on Mars, though the presence of large angular boulders is more prominent in most Martian landscapes. Analysis with the portable spectrometer confirmed the presence of mudstone and sandstone, with a few layers of conglomerates, mainly composed of illite and montmorillonite, with some samples of chlorite shales. The iron is almost all present in the form of hematite, thus reducing the occurrence of nontronite. Receding water from the Jurassic Sundance Sea left behind strata of salts in period of dryness. The salt is mainly sulfates, which (together with perchlorates) is present on Mars in various locations of geologic interest. White layers of gypsum, in the form of transparent selenite and white satin spar in the Morrison Formation, are accompanied by pink dikes of manganese sulfate in the lowest strata. Spectra will be further analyzed for water content and impurities. The results were extremely satisfactory, both in terms of Mars analog mineralogy and for what concerns collection of the samples with the various tools, and yielded useful outcomes for ISRU on Mars, described in the last section.

Difficulties and lessons learned: towards Mars

The experience in this project at MDRS was twofold informative, on the geology aspect and on the exploration aspect. The crew geologist, as an analog astronaut, had to face various difficulties in this mission: unexpected situations require a certain amount of flexibility. For example, the absence of the thermal camera, which can be considered analogous to an instrument malfunction, required a last-minute change in the details of the research project. Contingent situations, such as weather or communication failures cut short some of the EVAs, thus reducing the amount of time spent in the field, which of course is much less than what would be spent on a field expedition on Earth. Instruments which are very simple to use on Earth, such as the portable spectrometer or a marker to write on the clipboard, are much harder to use when the analog astronaut is incumbered by a space suit and bulky gloves. With much pride, our crew geologist managed to never break simulation, though at times he had to find ingenious solutions to be able to operate his instruments or to reach certain locations. On the other side, all these occurrences suggested ideas for better design of astronaut tools for use on planetary surfaces, where the presence of gravity needs to be added to the bulkiness of the garments (in orbit, astronauts experience the problem of large gloves, but can have a variety of tools just attached to their belts without their movements being made harder by gravity). Areas that require long walks because not accessible by vehicles suggest that surface EVAs will be probably shorter than in-orbit EVA: the crew geologist performed four EVAs in five days without particular overexertion, but a single EVA to Boilermaker Canyon was harder than multiple EVAs, because of the configuration of the terrain and the longer hiking distance. From a geologic perspective, the site also provided valuable lessons: besides the analogies with Martian mineralogy, the MDRS site gave information on how to use remote sensing to evaluate the abundance of the material, and some of the physical properties to facilitate collection. The mission also showed how much variety of material can be found within short distances, which suggests that more detailed surveys of interesting locations on Mars will be necessary to determine optimal places for human exploration and activities.

In conclusion, despites all the limitations to the fidelity of the simulation (gravity and atmospheric conditions, not-airtightness of the habitat and the space suits), the crew managed to achieve an adequate level of Mars analogy in the geologic EVAs. The landscape, the colors, the cumbersomeness of the suits, and the attention given by the crew to simulation details gave the impression of being exploring Mars and added to the challenges of the experience, producing outstanding results.

Bibliography

Clarke, J. (2003), The regolith geology of the MDRS study area, report.

Cooper, J. (2002), Mining Mars, CMA Management, September 2002, pp. 38-41.

Cuadros, J., and J. R. Michalski (2013), Investigation of Al-rich clays on Mars: evidence for kaolinite-smectite mixed-layer versus mixture of end-member phases, Icarus, vol. 222, pp. 296-306.

Curreri, P. A., and D. R. Criswell (1999), In situ production of solar power systems for exploration: potential for in situ rectenna production on Mars, AIP Conference proceedings, vol. 458, pp. 1623-1628.

Gundlach, B., and J. Blum (2013), A new method to determine the grain size of planetary regolith, Icarus, vol. 223, pp. 479-492.

Hargitai, E., ed. (2008), MDRS unofficial expedition guide, technical report by MDRS crews 42 and 71.

Horgan, B., J. A. Kahmann-Robinson, J. L. Bishop, and P. R. Christensen (2013), Climate change and a sequence of habitable ancient surface environments preserved in pedogenically altered sediments at Mawrth vallis, Mars, 44th Lunar and Planetary Science Conference.

Jones, E., G. Caprarelli, F. P. Mills, B. Doran, and J. Clarke (2014), An alternative approach to mapping thermophysical units from Martian termal inertia and albedo data using a combination of unsupervised classification techniques, Remote Sensing, vol. 6, pp. 5184-5237.

Muscatello, A. C., and E. Santiago-Maldonado (2012), Mars in-situ resource utilization technology evaluation, 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition.

Presley, M. A., and P. R. Christensen (2010), Thermal conductivity measurements of particulate materials, 4. Effect of bulk density for granular particles, Journal of Geophysical Research, vol. 115 no. E07003.

Sacksteder, K. R., and G. B. Sanders (2007), In-situ resource utilization for Lunar and Mars exploration, 45th AIAA Aerospace Sciences Meeting and Exhibit.

Sanders, G. B., and M. Duke (2005), In-situ resource utilization (ISRU) capability roadmap executive summary, NASA report.

Sanders, G. B., and W. E. Larson (2015), Final review of analog field campaigns for in situ resource utilization technology and capability maturation, Advances in Space Research, vol. 55, pp. 2381-2404.

Wan, L., R. Wendner, and G. Cusatis (2015), A novel material for in situ construction on Mars: experiments and numerical simulations, Northwestern University Center for Sustainable Engineering of Geological and Infrastructure Materials (SEGIM) internal report.

MDRS_Final_Geology_Report.docx

Science Report – January 13th

The Effectiveness of Radio Direction Finding for EVA Navigation in Situations of Low Visibility

Justin Mansell

MDRS Crew 186 Journalist

Motivation

Determining one’s position is a fundamental problem encountered in engineering. On Earth it is possible to use the constellation of GPS satellites to accurately pinpoint your position relative to a location where you would like to go. This capability does not currently exist on Mars, nor will it be likely to exist when humans first set foot on the planet. The difficulty of localizing an astronaut’s position relative to a location of interest is amplified in conditions of low visibility such as night or an unexpected dust storm. The resulting disorientation could greatly imperil any astronaut caught unprepared in such circumstances.

The purpose of this research was to explore how a disoriented astronaut might use radio signals to guide them to a target while on EVA. The core concept is to have the astronaut carry a radio antenna whose sensitivity is directional. Meanwhile, a navigation beacon at the target broadcasts a radio signal in all directions. If the astronaut is unable to locate their query by traditional means they can use the directional radio to determine the direction of the transmitting beacon, and therefore the direction they must walk to reach it.

Figure 1: Searching for the direction of maximum signal.

Experiment Setup

Prior to the mission I assembled a 3-element handheld Yagi antenna from schematics researched on the Internet. The particular design uses foldable elements made from steel tape measure and originated with Joe Leggio for use in amateur radio foxhunts [Leggio, 1993]. This design is lightweight and easy to stow due to the foldable elements. A coaxial cable with an SMA adapter allows the antenna to be plugged into virtually any portable ham radio.

The transmitter beacon is a commercial handheld ham radio with no special modifications. I created an audio file of a Morse signal toning the phrase, “This is the MDRS amateur navigation beacon crew 186”, and broadcast this signal from the beacon by connecting an iPod playing the audio file to the radio with an aux cable. In each test of the navigation experiment the radio beacon was located at the habitat and the Morse signal was broadcast at regular intervals by having a crewmember simply hold down the transmit button. A crewmember on EVA would then attempt to use the Yagi antenna to locate the direction of maximum signal and thereby the bearing to the habitat. The beacon was transmitted on the low power setting of the beacon radio (approximately 2.5 Watts) at a frequency of 146.565 MHz.

The Yagi antenna was used to aid EVA navigation on a total of four EVA’s, two of which were dedicated exclusively to testing its effectiveness. On the first two tests I followed a road on the outward trek and then attempted to follow the navigation signal along a straight line back to the habitat. This took me through unfamiliar terrain but did not adequately represent conditions of low visibility. On the later two tests I gave the antenna to a crewmember unfamiliar with amateur radio and covered the upper two thirds of their helmet with a cardboard visor. This restricted their vision to approximately 5 meters and prevented them from using landmarks to help them locate the habitat. Supporting members of the EVA then led the “lost astronaut” volunteer at least 2 kilometers from the habitat and monitored their safety as they attempted to return to the habitat using the radio alone.

Figure 2: Preparing the lost astronaut before EVA.

Results

The first two tests of the navigation antenna were useful for understanding its performance. The accuracy of the antenna in locating the direction to the beacon generally improves with distance. This is because close to the beacon the signal is strong enough to saturate the receiver even along its insensitive axis. The beacon signal therefore appears to originate from all directions. At greater distances the beacon signal is weak and careful pointing of the antenna may be required to receive it at all. At a distance of 4 kilometers the accuracy of the antenna in determining the bearing to the habitat appeared to be better than 10 degrees. This was reduced to over 90 degrees when within a kilometer of the habitat and worse still when even nearer.

During the tests I found that the poor accuracy of the antenna near the transmitter could be mitigated in the following way. The antenna is least sensitive to incoming signal along a direction parallel to the receiving elements. By searching instead for the direction of minimum signal I could deduce that the beacon was located at a right angle to my current pointing direction. This provided acceptable accuracy at sub-kilometer distances.

On the tests with the cardboard visor limiting the astronaut’s vision the difficulty of navigating by natural senses alone was professed by the arcing paths participants took prior to and in between broadcasts of the navigation beacon. In fact, on the final test the mock “lost astronaut” walked a complete circle with a radius less than 100 m in between two broadcasts of the beacon. To limit the drift of the astronaut’s path it was necessary to decrease the intervals between the beacon transmissions to a nearly continuous broadcast. In both tests with the cardboard visor the astronaut was able successfully navigate to within 500 meters of the habitat despite limited knowledge of their initial position and orientation.

I also note that the surrounding terrain did not appear to have a significant detrimental affect of the performance of the antenna, but this has been difficult to quantify.

Figure 3: Scanning to find the bearing to the hab.

Recommendations

The navigation experiments of MDRS Crew 186 suggest that a handheld directional antenna is a simple and effective means of EVA navigation in low visibility conditions. However, the current set up has several limitations which are noted below.

The current means of searching for the direction of maximum signal provides only the direct bearing to the transmitter beacon. As was found in several of the tests, following a direct path to the beacon is not always possible due to intervening terrain. The user is then on their own to determine an appropriate detour and this may act to further their disorientation. Additional information may be required beyond that provided by a directional antenna in order to navigate successfully.

At distances close to the transmitter the technique of searching for a direction at right angles to the directions of minimum signal proved satisfactory in our experiments. However, because there are always two such directions the astronaut is at risk of following a path directly away from the beacon instead of towards it. This is possible when receiving along the sensitive axis of the antenna as well, but is less likely because the signal strength received by the back lobe of the antenna is generally much weaker compared to the front. Instead of searching for the direction of minimum signal, a better solution would be to attach an attenuator between the antenna and receiver so that the astronaut can reduce the received signal when close to the beacon.

Finally, the rapid drift of participants from their initial heading in between broadcasts of the beacon suggests that either the navigation beacon should be broadcast continuously or astronauts should have some way of preserving their orientation while walking. The later option is desirable because terrain, weather, or the need to handle equipment may temporarily prevent the signal from being received. On Earth an obvious solution is to mark the desired bearing on a compass and follow it accordingly, but this will not work on Mars due to the lack of a global magnetic field.

Figure 4: Finding the habitat using its radio beacon.

Bibliography

Leggios, J. (1993), Tape Measure Beam Optimized for Radio Direction Finding, http://theleggios.net/wb2hol/projects/rdf/tape_bm.htm.

Acknowledgements

I would like to thank Geoffrey Andrews, Jennifer Pouplin, and Cesare Guariniello at Purdue University for their assistance fabricating and testing the Yagi antenna prior to the mission.

Nav Experiment 13Jan2018.docx

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