| A subjective assessment of alternative mission architectures for the human exploration of Mars at NASA using multicriteria decis Recent countries visiting this post |  |
 | 4 | United States |
 | 1 | China |
| A subjective assessment of alternative mission architectures for the human exploration of Mars at NASA using multicriteria decis Recent countries visiting this post | |
| 4 | United States |
| 1 | China |