- they do not have significant gravity fields of their own, so missions to them do not “land”
- Although there are several thousand NEOs, few of them are possible destinations for human missions.
- On a NEO mission, a broken system must be both fixable and fixed by the crew.
- Astronauts in low Earth orbit are largely protected from radiation because they orbit beneath the van Allen radiation belts, which protect life on the Earth. On the Moon, we can use regolith to shield crew but for now, such mass is not available to astronauts traveling in deep space.
- Is it worth it? [comment: asteroid trip] That will be the subject of my next post.
I do not favor a trip to an asteroid first. To the moon first, I say. Instead of flags and footprints, we should settle it. If this can't be done on the moon, where can it be done at all?