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Different aspects of the mission such as crew size, experience, excursion time, exploration time, mobility, range, and instrumentation affect knowledge. All of these with the exception of instrumentation will be modeled. The reason instrumentation is not modeled here is that it varies by mission depending on the specific science objectives of that mission. For example, a mission focused on geology will have very different instruments than a mission focused on climatology. Instrumentation is further discussed in Appendix 9.5. During the later Apollo missions approximately one third of the total time spent on the Moon surface was spent during an excursion (Table 2). The earlier Apollo missions did not have as high of an excursion time for two possible reasons. The first is the lack of experience. Later Apollo missions were able to gain experience with surface operations on both the Earth and Moon from the first Apollo mission. The other reason is because the first few Apollo missions did not have science as their primary mission objective. Only Apollo 15-17 had “extensive scientific investigation” of Moon as a primary mission purpose whereas Apollo 11’s primary mission was a manned lunar landing demonstration (NASA website, 2004). The primary mission for Apollo 12-14 was precision piloted landing and systematic lunar exploration. Thus, experience had an effect on the excursion time for lunar missions, and had a maximum of 30% of the total lunar stay time for a mission.

Table 2: Apollo mission details (NASA website, 2004)

kg duration (hrs) outside LM[min] max d from LM (m) %outside

Apollo 11 21.6 22 152 61 11.5

Apollo 12 34.3 31 465 411 25

Apollo 14 42.3 33 563 1454 28.4

Apollo 15 77.3 67 1115 5020 27.7

Apollo 16 95.7 71 1214 4600 28.5

Apollo 17 110.5 75 1324 7629 29.4

Each excursion had a predetermined plan, however there were times when independent exploration was allowed and carried out by the astronauts. An example of independent exploration results was the orange pyroclastic glass discovered in Shorty Crater by Apollo 17. This exploration was not dictated by ground. When the astronauts were exploring in the area, they had 30 minutes of rapid assessment and gathering before the mission controllers were even aware of the events. Independent exploration allows a human to fully utilize his/her training, experience and senses to return knowledge, either as samples, pictures, observations, technology used, or operational procedures.

Using the number of crew, excursion time, exploration time, and mobility, the coverage area during exploration can be determined. Assuming an experienced crew, the excursion time can be maximized as 30% of the mission surface time, which is similar to the Apollo missions. Exploration is defined by examining the surrounding area within 10 meters of the astronaut, since this is the range for which the human eye has an optimal ability to determine unique aspects of the surroundings (Schmitt, personal communications). It is assumed that some portion of an excursion is spent performing this exploration process. For this knowledge model, 30% of the excursion time was spent as this independent exploration time. This could vary a great deal on an

excursion by excursion basis, but it was approximated based on personal communications with Jack Schmitt. There are three types of mobility, a walking pace (or gait) while traversing without exploring, a slower exploration pace, and a rover speed.

The walking pace is based on the design speed of an Apollo astronaut and determines the maximum traveling distance per day from the starting point, presumably a lunar module . The exploration pace is estimated as four times slower than the gait because the human is more carefully analyzing the environment and perhaps taking measurements or pictures (NASA Headquarters website, 2004). The rover pace is based on the Apollo Lunar Rover (Apollomaniacs, 2004) and is capable of expanding the maximum traveling distance per day. These parameters are summarized in Table 3 and are used to determine how much coverage per day can be accomplished.

Coverage is defined as the area traversed at an exploration pace and can be used to quantify how much knowledge potential is gained. As more area is explored, a greater amount of knowledge is potentially gained, either from science or resource data, or technical and operational procedures. Since exploration pace is slower than the maximum speed by astronauts, either by rover or by walking, there is a certain amount of coverage than can be achieved per day. The number of crew available will directly affect this coverage, which is shown in Figure 18. There is a clear direct relationship between the number of crew and the maximum exploration coverage achievable per day. The coverage achieved while walking can either be completed by increasing the number of days on the surface, or by increasing the number of crew. If walking is the fastest mode of transportation, 100% coverage can be achieved rather easily, after which the knowledge potential is maximized in that particular landing site. Using a rover increases mobility, and in this case, the maximum area that may be traversed in a day dramatically increases, decreasing the percent area covered per day. To increase the exploration coverage requires either a longer stay than the non-rover case or a larger crew.

Table 3: Knowledge drivers model parameters outside LM fraction 0.3

exploration time 0.3 traveling pace (gait)(m/hr) 3600 exploration pace(m/hr) 900 rover pace (m/hr) 14000

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2 4 6 8 10 12

Number of Crew

Percent Coverage

No Rover Rover Total Area = 81,430 m^2

Total Area = 316,673 m^2

Figure 18: Knowledge potential: maximum exploration coverage per day versus number of crew

This model can also incorporate faster speed rovers. Introduction of a pressurized rover that allows astronauts to stay outside of the base can further expand knowledge potential as seen in Figure 19. By creating a remote base, travel can be further expanded from the remote location, thus expanding the knowledge potential from exploration.

Figure 19: Expanding the exploration potential using a remote base (Hoffman, 1998)

Another possible method of increasing knowledge potential is to increase the amount of independent exploration time per excursion. In fact, as missions proceed, a greater amount of independent and flexible time for the astronauts should be encouraged, especially as communication delays increase for farther missions (Schmitt, personal communication). In conclusion, the knowledge potential of a mission can be predicted

Powerplant exclusion

zone

Central base

Maximum

traverse distance Maximum traverse distance

Remote field camp at maximum range from central base

Image by MIT OpenCourseWare. Adapted from Hoffman, 1998.

by the exploration coverage, which is affected by the number of crew, experience, excursion time, exploration time, and mobility.