Building a space station, in which astronauts would live for a conside

We had some fun with this one in a recent YouTube webinar on strengthen, weaken, and assumption questions. Well, I had fun. I dunno about the rest of you.

Anyway, whenever I see an assumption question, my first thought is that I need to understand the conclusion – EXACTLY in the author’s words, not my words – and then figure out how the author reached that conclusion. So in this case, the conclusion is just the key pieces of that first sentence: “building a space station is essential.”

And how did the author arrive at that conclusion? Basically, it’s just that last sentence: “for future missions to explore Mars, we will need the medical knowledge that the space station project will give us about the limits of human capacities to live in spacecraft for an extended time.”

Fair enough. And we’re looking for a necessary assumption, which means that the correct answer will reinforce the conclusion, perhaps in some small, subtle way. And more importantly, the correct answer is something that we NEED in order to draw the conclusion.


A lot of people discard this one right away, since the passage doesn’t say anything about robots. But that’s not a great idea: by definition, a necessary assumption is something that is NOT actually mentioned in the passage. It just has to be something that allows the conclusion to be properly drawn.

And this might be the least exciting answer choice ever, but we really do need to assume (A). After all, why would we need “medical knowledge... about the limits of human capacities to live in spacecraft for an extended time” if we’re just going to send robots up there? Of course we have to assume that people will be making the trip, not just robots.

So let’s keep (A).


There’s no reason why we need to assume this in order to draw the conclusion properly. An astronaut is, by definition, somebody who explores space – and the entire passage revolves around the need for medical knowledge for “future missions to explore Mars.”

We certainly don’t need to assume that the astronauts are typical of ordinary human beings: by definition, the space station and Mars missions will both be conducted by astronauts. It doesn’t matter at all if those astronauts resemble ordinary human beings: either way, we’ll need to know about the limits of the space explorers’ (i.e., astronauts) capacities – regardless of whether those astronauts are “ordinary” or not.

So (B) can be eliminated.


The key here is one little modifier: “unforeseen.” (C) is saying that “no unforeseen medical problems will arise” on that first Mars mission, and that’s airtight language. It literally means that if there are any medical problems, we already know everything about them.

So if (C) is true, the entire passage falls apart: why would we build a space station to acquire medical knowledge if we don’t really need any more medical knowledge? That makes no sense. We can get rid of (C).


That’s nice. Exploring the solar system sounds like fun. (Insert horrible, childish joke about Uranus here.) But the entire passage is built around the idea that we’ll need medical knowledge for future missions to explore Mars. The rest of the solar system is completely irrelevant. (D) is out.


The key here is another little modifier: “insurmountable.” Literally, that word means “cannot be conquered” or “cannot be overcome.” So then (E) is saying that living in a spaceship for an extended time presents medical problems that can NEVER be overcome. And if that’s true, then why the heck would we build a space station? Whatever those medical problems are – hair loss, hemorrhoids, bunions, acid reflux, crow’s feet – we can’t fix them if (E) is true, and the passage falls apart once again.

So we’re left with (A).