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MDRS Crew 69 Summary
The following is the summary report of Mars Desert Research Station (MDRS) Crew 69, which recently completed its operations in southern Utah. A complete report on this year's field season at the MDRS will be given at the 11th International Mars Society Convention, which will be held at the University of Colorado, Boulder, August 14-17, 2008. Registration is now open at www.marssociety.org.
Crew 69 mission patch.
Overview:
The following are the results and experiences of Crew 69 to the Mars Desert Research Station. Crew 69 was the second all-student crew from the Georgia Institute of Technology (Georgia Tech), and the fourth crew organized by GT. See http://www.gtmars.us for more information on our crew.
Extended Communications Coverage:
Our radio testing for this mission was remarkably successful. As in past years, we used ham radios to communicate, meaning that everyone on the crew earned their ham radio license prior to MDRS. Also like last year, we set up a voice repeater and digipeater on Skyline Rim. Fortunately, we had enough sunlight this year that the solar panel successfully charged the batteries. The remote setup included two radio transceivers, one for voice and one for packet data; two 12 volt car batteries; a magnetic mount halfwave antenna; a j-pole antenna; a solar charger; and a solar panel. The repeater was placed at Skyline Rim and turned on Wednesday, March 19 and retrieved on Friday, March 28. It was used successfully on every EVA that required ATVs; using it, we were able to maintain voice communications between HabCom and EVA at every place that we went. Using APRS (Amateur Position Reporting System), we were also able to plot each crew member´s position on a topographic computer map and watch them travel in real time. We had radio coverage at both Lithe Canyon and up Hubble Highway, which are about as far as we would ever expect to go on an EVA. Crew members on each EVA were also able to communicate with one another via radios and headphones wired into their helmets. This year, we chose to only use the repeater on ATV EVAs and used simplex for local communication to save batteries on the repeater. We were successful, as the repeater´s batteries lasted for the duration and each had an ending voltage of 11.87 volts. We also put each handheld radio and the repeaters on the lowest power setting possible, all to conserve battery life. Once while on an EVA through a canyon we did have to turn our radios to high power to get into the repeater, but the signal was perfect as soon as we did. We never had to use our spare batteries on any EVA, a measure of our success in battery life conservation.
We set up a base station in the Hab, with a magnetic mount half wave antenna on top of the Hab. This was great for communicating with field stations, and it had no problem getting into or hearing the repeater.
Possible improvements for next year include the use of a wind turbine to augment power in case of clouds; the use of speaker microphones in the helmets as opposed to earbuds, so the earbuds do not need to be taped into ears; and the addition of a high frequency station for emergency contact and outreach to schools with HF capability.
University Rover Challenge Rover Development
The main focus of the rover tests completed at MDRS was the maneuverability of the rover in the simulated Mars environment. Things observed included turning radius, ability to climb, and descend various inclinations, and traction in different soil types. Another outcome of these tests was to gage the durability and endurance of the rover in non-laboratory conditions. These tests revealed that the frame was robust enough to survive the demands of the terrain, the battery life was sufficient, and the effect of dust, sand and grit in the electronic and mechanical components was minimal. A third important objective was the documentation the geological operating conditions, such as rock size, elevation changes, line of sight, and ground hardness. These tests provided a chance to analyze the performance of current conceptual designs as well as form a basis for the next stage in the final design of the rover.
Mars Radiation Environment Modeling (MarsREM)
Unfortunately, a miscommunication regarding equipment used during the first set of MarsREM measurements and the size of corer available prevented the continuation of this research at MDRS. However, the project has been much more clearly defined and will be significantly easier to continue at a later date. There is also quite a bit of procedure and analysis remaining to be determined and conducted on the first set of samples, leaving time for the addition of data in the future.
Wind Turbine
The base, tower and guy wires were assembled on the hilltop, and the generator and electrical system were installed afterwards. The electrical system consisted of three 12 volt batteries (partially discharged) connected in parallel, a 400 watt inverter providing AC power to a "dump load" of three 100 watt light bulbs, and a charge controller which would shift the power input from battery-charging to the dump load when the batteries were charged up.
Unfortunately, it seems the inverter & bulbs may not be a useful dump load - as the charge controller started sending power to the dump load, the inverter would turn on, but when the bulbs started consuming power the input voltage would drop. When this voltage dropped below 11 volts, the inverter would enter an error state and need to be reset via its power switch. It's plausible that, once the batteries were fully charged so that the power is always going to the dump load (rather than just during gusts), the power to the inverter would be consistent enough for it to run well. However, if it enters an error state before this point someone will have to manually reset it before it will again pass power to the bulbs. An alternative dump load will probably be required to minimize the human attention demanded by the system.
Science
Fluid intake was tracked on a regular basis for the crew members. The average amount of fluid intake per crew member was 8 cups. The maximum fluid intake was around 18 cups. 1 cup of fluid refers to 6 oz. The fluid intake increased considerably when a crew member was involved in an EVA. This was a vital study as it maintains a healthy fluid intake in dry desert conditions, thus, preventing dehydration. In order to keep track of nutrition, food intake was also maintained by the crew members individually for disciplinary purposes using online software.
An incline study was performed to test the comfort of navigating inclines of varying slope angles in EVA suits. The subjects were volunteers from the crew. To test the mobility and safety of conducting field studies in EVA suits, the subjects were asked to stand upright facing up the slope, followed by crouching at the same position, and then they were asked to turn and stand facing down the slops, and crouching in that position. The comfort of each subject was recorded for various incline angles, and different soil types, ranging from rocky and loose to hard red soil. In order to quantify and thus, analyze the data, the comfort level was decided between 1 and 5, where 1 refers to the most comfort and 5 refers to the least comfort that a subject experiences at a particular position at a particular incline. All subjects reported maximum difficulty in EVA suit mobility at locations with a crumbly red soil type and at an angle of 45 degrees. This soil type is most prevalent in and around the Hab, and usually inclines are above 30 degrees, thus, it is suggested based on the study that caution and carrying a walking stick during EVA suit field studies may prove beneficial for crews in future during EVA. Further studies on the EVA suit mobility will be appreciated.
The plants in the Green Hab were watered every alternate day. It was observed that the corn and radish plants had browning leaves. Around 2 buckets of water seemed sufficient for the plants for the afore mentioned watering schedule. The water hyacinths were also transplanted from AT2 to AT1. The water hyacinths seemed to be healthy and they rapidly populated the newly transplanted tank. Now AT1 and AT2 are considerably populated with water hyacinths, and future crews may need to plan for this fast growth and further transplantations, or any other suitable options. The pH was measured twice for all the aquatic tanks, and the pH levels were found to be between 7.5 and 8.5 in all the tanks during both measurements. It is suggested that future crews also measure the pH of the aquatic tanks at a regular basis. There is a big container of swimming pool acid available in the Green Hab if future crews may need to use it.
Future suggestions also include acquiring human factors study approvals beforehand, and planning long term for the human factors study.
GreenHab Circulation Improvement
Currently, AT4 is connected to the left filter below the Bioballs in order to have constant circulation between the entire system. This requires that the valve to AT1 always be open. We put a float switch (the NO/NC determined by Crew 47 to be only partially functional) in AT4 to make sure that the pump stops when it gets too low.
The feed into AT1 was shifted to back instead of the front (which is right next to the output). This will force the water to flow across the tank in order to exit, thereby increasing flow. In AT3, we added some aluminum ventilation scrap in front of the outlet in order to keep the duckweed away from the mesh filter, thereby avoiding clogged flow between AT3 and AT4.
A further recommendation for the Greenhab is to correct the fact that the filters are constantly clogged. Changing/cleaning these filters takes a lot of time, effort, and occasionally creativity. To ensure crews maintain the system, generic ready-made filters should be set up at every point so that changing filters is easy. Currently, it appears a daunting task for someone who has never seen the system to come in and replace the filters as they currently exist.
The following are the results and experiences of Crew 69 to the Mars Desert Research Station. Crew 69 was the second all-student crew from the Georgia Institute of Technology (Georgia Tech), and the fourth crew organized by GT. See http://www.gtmars.us for more information on our crew.
Extended Communications Coverage:
Our radio testing for this mission was remarkably successful. As in past years, we used ham radios to communicate, meaning that everyone on the crew earned their ham radio license prior to MDRS. Also like last year, we set up a voice repeater and digipeater on Skyline Rim. Fortunately, we had enough sunlight this year that the solar panel successfully charged the batteries. The remote setup included two radio transceivers, one for voice and one for packet data; two 12 volt car batteries; a magnetic mount halfwave antenna; a j-pole antenna; a solar charger; and a solar panel. The repeater was placed at Skyline Rim and turned on Wednesday, March 19 and retrieved on Friday, March 28. It was used successfully on every EVA that required ATVs; using it, we were able to maintain voice communications between HabCom and EVA at every place that we went. Using APRS (Amateur Position Reporting System), we were also able to plot each crew member´s position on a topographic computer map and watch them travel in real time. We had radio coverage at both Lithe Canyon and up Hubble Highway, which are about as far as we would ever expect to go on an EVA. Crew members on each EVA were also able to communicate with one another via radios and headphones wired into their helmets. This year, we chose to only use the repeater on ATV EVAs and used simplex for local communication to save batteries on the repeater. We were successful, as the repeater´s batteries lasted for the duration and each had an ending voltage of 11.87 volts. We also put each handheld radio and the repeaters on the lowest power setting possible, all to conserve battery life. Once while on an EVA through a canyon we did have to turn our radios to high power to get into the repeater, but the signal was perfect as soon as we did. We never had to use our spare batteries on any EVA, a measure of our success in battery life conservation.
We set up a base station in the Hab, with a magnetic mount half wave antenna on top of the Hab. This was great for communicating with field stations, and it had no problem getting into or hearing the repeater.
Possible improvements for next year include the use of a wind turbine to augment power in case of clouds; the use of speaker microphones in the helmets as opposed to earbuds, so the earbuds do not need to be taped into ears; and the addition of a high frequency station for emergency contact and outreach to schools with HF capability.
University Rover Challenge Rover Development
The main focus of the rover tests completed at MDRS was the maneuverability of the rover in the simulated Mars environment. Things observed included turning radius, ability to climb, and descend various inclinations, and traction in different soil types. Another outcome of these tests was to gage the durability and endurance of the rover in non-laboratory conditions. These tests revealed that the frame was robust enough to survive the demands of the terrain, the battery life was sufficient, and the effect of dust, sand and grit in the electronic and mechanical components was minimal. A third important objective was the documentation the geological operating conditions, such as rock size, elevation changes, line of sight, and ground hardness. These tests provided a chance to analyze the performance of current conceptual designs as well as form a basis for the next stage in the final design of the rover.
Mars Radiation Environment Modeling (MarsREM)
Unfortunately, a miscommunication regarding equipment used during the first set of MarsREM measurements and the size of corer available prevented the continuation of this research at MDRS. However, the project has been much more clearly defined and will be significantly easier to continue at a later date. There is also quite a bit of procedure and analysis remaining to be determined and conducted on the first set of samples, leaving time for the addition of data in the future.
Wind Turbine
The base, tower and guy wires were assembled on the hilltop, and the generator and electrical system were installed afterwards. The electrical system consisted of three 12 volt batteries (partially discharged) connected in parallel, a 400 watt inverter providing AC power to a "dump load" of three 100 watt light bulbs, and a charge controller which would shift the power input from battery-charging to the dump load when the batteries were charged up.
Unfortunately, it seems the inverter & bulbs may not be a useful dump load - as the charge controller started sending power to the dump load, the inverter would turn on, but when the bulbs started consuming power the input voltage would drop. When this voltage dropped below 11 volts, the inverter would enter an error state and need to be reset via its power switch. It's plausible that, once the batteries were fully charged so that the power is always going to the dump load (rather than just during gusts), the power to the inverter would be consistent enough for it to run well. However, if it enters an error state before this point someone will have to manually reset it before it will again pass power to the bulbs. An alternative dump load will probably be required to minimize the human attention demanded by the system.
Science
Fluid intake was tracked on a regular basis for the crew members. The average amount of fluid intake per crew member was 8 cups. The maximum fluid intake was around 18 cups. 1 cup of fluid refers to 6 oz. The fluid intake increased considerably when a crew member was involved in an EVA. This was a vital study as it maintains a healthy fluid intake in dry desert conditions, thus, preventing dehydration. In order to keep track of nutrition, food intake was also maintained by the crew members individually for disciplinary purposes using online software.
An incline study was performed to test the comfort of navigating inclines of varying slope angles in EVA suits. The subjects were volunteers from the crew. To test the mobility and safety of conducting field studies in EVA suits, the subjects were asked to stand upright facing up the slope, followed by crouching at the same position, and then they were asked to turn and stand facing down the slops, and crouching in that position. The comfort of each subject was recorded for various incline angles, and different soil types, ranging from rocky and loose to hard red soil. In order to quantify and thus, analyze the data, the comfort level was decided between 1 and 5, where 1 refers to the most comfort and 5 refers to the least comfort that a subject experiences at a particular position at a particular incline. All subjects reported maximum difficulty in EVA suit mobility at locations with a crumbly red soil type and at an angle of 45 degrees. This soil type is most prevalent in and around the Hab, and usually inclines are above 30 degrees, thus, it is suggested based on the study that caution and carrying a walking stick during EVA suit field studies may prove beneficial for crews in future during EVA. Further studies on the EVA suit mobility will be appreciated.
The plants in the Green Hab were watered every alternate day. It was observed that the corn and radish plants had browning leaves. Around 2 buckets of water seemed sufficient for the plants for the afore mentioned watering schedule. The water hyacinths were also transplanted from AT2 to AT1. The water hyacinths seemed to be healthy and they rapidly populated the newly transplanted tank. Now AT1 and AT2 are considerably populated with water hyacinths, and future crews may need to plan for this fast growth and further transplantations, or any other suitable options. The pH was measured twice for all the aquatic tanks, and the pH levels were found to be between 7.5 and 8.5 in all the tanks during both measurements. It is suggested that future crews also measure the pH of the aquatic tanks at a regular basis. There is a big container of swimming pool acid available in the Green Hab if future crews may need to use it.
Future suggestions also include acquiring human factors study approvals beforehand, and planning long term for the human factors study.
GreenHab Circulation Improvement
Currently, AT4 is connected to the left filter below the Bioballs in order to have constant circulation between the entire system. This requires that the valve to AT1 always be open. We put a float switch (the NO/NC determined by Crew 47 to be only partially functional) in AT4 to make sure that the pump stops when it gets too low.
The feed into AT1 was shifted to back instead of the front (which is right next to the output). This will force the water to flow across the tank in order to exit, thereby increasing flow. In AT3, we added some aluminum ventilation scrap in front of the outlet in order to keep the duckweed away from the mesh filter, thereby avoiding clogged flow between AT3 and AT4.
A further recommendation for the Greenhab is to correct the fact that the filters are constantly clogged. Changing/cleaning these filters takes a lot of time, effort, and occasionally creativity. To ensure crews maintain the system, generic ready-made filters should be set up at every point so that changing filters is easy. Currently, it appears a daunting task for someone who has never seen the system to come in and replace the filters as they currently exist.
