Exercise - Develop a recommendation of Moon rock samples to be collected
Let's take a step back and compare the samples that are running low to all the samples collected on Apollo missions. We can compare the total weight from the needed_samples DataFrame to the rock_samples DataFrame.
needed_samples.groupby('Type')['Weight (kg)'].sum()
Type
Basalt 17.4234
Breccia 10.1185
Name: Weight (kg), dtype: float64
rock_samples.groupby('Type')['Weight (kg)'].sum()
Type
Basalt 93.14077
Breccia 168.88075
Core 19.93587
Crustal 4.74469
Soil 87.58981
Special 0.74410
Name: Weight (kg), dtype: float64
This bit of information really stands out: we didn't have many Crustal rocks in the first place.
We can add Crustal rocks to the set of needed samples:
needed_samples = pd.concat([needed_samples,rock_samples.loc[rock_samples['Type'] == 'Crustal']])
needed_samples.info()
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 ID 68 non-null int64
1 Mission 68 non-null object
2 Type 68 non-null object
3 Subtype 68 non-null object
4 Weight (kg) 68 non-null float64
5 Pristine (%) 68 non-null float64
6 Remaining (kg) 68 non-null float64
Summary of needed samples
The final step is to consolidate everything we know into one table that can be shared with the astronauts. First, we need a column for each type of rock that we want more samples of:
needed_samples_overview = pd.DataFrame()
needed_samples_overview['Type'] = needed_samples.Type.unique()
needed_samples_overview
| Index | Type |
|---|---|
| 0 | Basalt |
| 1 | Breccia |
| 2 | Crustal |
Next, we want the total weight of each type of rock that was originally collected:
needed_sample_weights = needed_samples.groupby('Type')['Weight (kg)'].sum().reset_index()
needed_samples_overview = pd.merge(needed_samples_overview, needed_sample_weights, on='Type')
needed_samples_overview.rename(columns={'Weight (kg)':'Total weight (kg)'}, inplace=True)
needed_samples_overview
| Index | Type | Total weight (kg) |
|---|---|---|
| 0 | Basalt | 17.42340 |
| 1 | Breccia | 10.11850 |
| 2 | Crustal | 4.74469 |
When astronauts are up on the Moon, one way they can identify rocks is by their size. If we can give them an estimated size of each type of rock that might make their collection process easier.
needed_sample_ave_weights = needed_samples.groupby('Type')['Weight (kg)'].mean().reset_index()
needed_samples_overview = pd.merge(needed_samples_overview, needed_sample_ave_weights, on='Type')
needed_samples_overview.rename(columns={'Weight (kg)':'Average weight (kg)'}, inplace=True)
needed_samples_overview
| Index | Type | Total weight (kg) | Average weight (kg) |
|---|---|---|---|
| 0 | Basalt | 17.42340 | 1.244529 |
| 1 | Breccia | 10.11850 | 1.264812 |
| 2 | Crustal | 4.74469 | 0.103145 |
Crustals are small! They're probably harder to spot, so no wonder we don't have many of them.
We probably want to give the astronauts some indication of how many of each type we want them to collect. So, for the three types we're looking for, we should grab the total number we have of each type and get the remaining percentage of each type of rock.
total_rock_count = rock_samples.groupby('Type')['ID'].count().reset_index()
needed_samples_overview = pd.merge(needed_samples_overview, total_rock_count, on='Type')
needed_samples_overview.rename(columns={'ID':'Number of samples'}, inplace=True)
total_rocks = needed_samples_overview['Number of samples'].sum()
needed_samples_overview['Percentage of rocks'] = needed_samples_overview['Number of samples'] / total_rocks
needed_samples_overview
| Index | Type | Total weight (kg) | Average weight (kg) | Number of samples | Percentage of rocks |
|---|---|---|---|---|---|
| 0 | Basalt | 17.42340 | 1.244529 | 351 | 0.258850 |
| 1 | Breccia | 10.11850 | 1.264812 | 959 | 0.707227 |
| 2 | Crustal | 4.74469 | 0.103145 | 46 | 0.033923 |
And finally, to tie it all back into a recommendation to the Artemis program, we can determine the average weight of samples we estimated in the preceding unit.
artemis_ave_weight = artemis_mission['Estimated sample weight (kg)'].mean()
artemis_ave_weight
63.61713411579792
We can use this number to determine how many of each rock we want the astronauts to aim to collect:
needed_samples_overview['Weight to collect'] = needed_samples_overview['Percentage of rocks'] * artemis_ave_weight
needed_samples_overview['Rocks to collect'] = needed_samples_overview['Weight to collect'] / needed_samples_overview['Average weight (kg)']
needed_samples_overview
| Index | Type | Total weight (kg) | Average weight (kg) | Number of samples | Percentage of rocks | Weight to collect | Rocks to collect |
|---|---|---|---|---|---|---|---|
| 0 | Basalt | 17.42340 | 1.244529 | 351 | 0.258850 | 16.467267 | 13.231731 |
| 1 | Breccia | 10.11850 | 1.264813 | 959 | 0.707227 | 44.991764 | 35.571884 |
| 2 | Crustal | 4.74469 | 0.103145 | 46 | 0.033923 | 2.158103 | 20.922917 |
So, we might tell the Artemis astronauts to try to collect 13 Basalt rocks, 35 Breccia rocks, and 20 Crustal rocks. Whew!