Self-study
Support The only physical factor preventing a human journey to Mars has been weight. ████████ ██████ ████ ██ ██████ █ ████████████ ██████████ ██ ████ ███ ████ █████ ████ ████ ███ ████████ █████ ███ █████ ██ ██ ████████ ████ ██████ █ ██████ ███ ████████ ████ █████████ ████████ ████ ██████ ██ █████████ ████████████ ██████████ ██ ██████ ███ ███████ ████ █████ ████ ████ ████████████ ████ ███ ███████ ██████████ ███ ███ ██████ █████ ██████████ ██ ██ ████████ ███ ██████ ██ ██ ██ ████ ██ █ ██████████ ████ ███████ ████ ██████ ███ ████ ███████
Summary
The argument claims that people can now journey to Mars and back. How is this possible? Well, the only reason we couldn’t do that before was the weight of the spacecraft, from all the fuel it would need to carry to get to Mars and back. But now there’s a device that can refill the spacecraft’s fuel tanks using Mars’ atmosphere!
Notable Assumptions
In order for a spacecraft to launch while carrying enough fuel to get to Mars, as well as the new device, it has to not be too heavy. And we know that the weight of fuel to get to Mars and back is too heavy. So, the argument requires two related assumptions:
- The new device weighs less than the fuel needed to return from Mars.
- The total weight of a spacecraft carrying the fuel needed to reach Mars plus the new device is not too heavy to launch.
9.
Which one of the following ██ ██ ██████████ ██ █████ ███ ████████ ████████
a
The amount of ████ ██████ ███ █ ██████████ ██ ██████ ████ ████ ██ ███ ████ ██ ███ ██████ ██ ████ ██████ ██ ██████ ████ █████ ██ █████
It doesn’t matter whether these amounts are the same or different, as long as replacing the return fuel with the new device can lower the spacecraft’s weight enough. So, this is irrelevant.
b
The fuel manufactured ████ ███ ███████ ██████████ █████ ███ ██████ ██ ███████████ ████ ███ ████ ████ ██ ██████ ██ █████
It’s irrelevant whether the Mars-manufactured fuel would be exactly the same as the Earth-manufactured fuel, as long as both of them can propel the spacecraft.
c
The device for █████████████ ████ ████ ███ ███████ ██████████ █████ ███ ████ ██ ███ ██ ███ █████████ ██████ ██████ ██████
The argument only asserts that it’s now possible to send a human journey to Mars and back, without any claims about how much living space the crew would have. That makes this irrelevant.
d
A conventional spacecraft ████████ ████ ███ ██████ █████ ███ ██ ███████████ ████ █████████ ██ █████████ ████ ███████ ██████████ █████████ ████
The argument is focused on the physical possibility of a human journey to Mars and back. The amount is would cost is irrelevant.
e
The device for █████████████ ████ ███ ███ ██████ ██ █████ ██████ ████ ████ ███ █████ ██ ████ ████ █ ████████████ ██████████ █████ █████████ ████ ██ █████ ████ █████ ███ ███ ██████ █████
If we negate this—if the new device weighs the same as would the return fuel, or more—then the argument falls apart. There would be no reduction in weight, so it wouldn’t be possible for the spacecraft to launch at all. That’s why this is necessary.