Flight Incorporated has just recently posted these advertisements:
Buying Fuel for High Prices!
Buying fuel for our spaceships
Fuel in possession/fuel needed in gallons: $\Delta = 1000/\infty$
Current Bank Balance: $100,000,000,000.00
Required Balance = $\infty$ as fuel required is infinite
We will pay 1 gram of AN:92 per gallon of fuel.
We need compressors... and oxygen tanks! You will be paid in brass-plated troughs with your name on a plate. Under the plating is a layer of plastic. Engraved on the bottom is our company name and logo.
The following was posted on Flight Inc.'s website.
Remember to strap in your seat belts! Mass and speed increase simultaneously. Time is dilated. Communications will be offline, as no form of communication travels fast enough. Prepare for a breathtaking tunnel view.
Time to destination is: $cyears=year$
$C$ is the undisputable speed limit, proposed by the maker of $e=mc^2$ What we're doing is impossible, but that's never stopped us!
Classical engine runs off of hydrogen. Liquid fueled rocket needs two tanks for propellant and oxidizer. System cannot be distorted by mass increase.
What do they need the fuel for and what are they being paid in?
Note: No knowledge of science fiction is required to solve this. Tear every line apart :)
Trouble deciphering our ads?
AN is an abbreviation for something related to materials. (Atomic Number) Basic science knowledge is required. We don't buy from people who don't know science. We love the periodic table... Who cares about speed limits, even those universe-wide?
AN is an abbreviation for Atomic Number. This puzzle is related to Einstein, relativity, and classical physics. The speed that they are trying to go to (or near it) does weird things to a spacecraft.
They are trying to travel at the speed of light. The oxygen is related to combustion and the hydrogen is the fuel.