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Stonehedge
Sometimes I think people don't realise how space works.
When you get into space you're orbiting Earth at about 17,500 mph. However, Earth is orbiting the sun at 70,500 mph so although relative to Earth you're moving at 17,500 mph, relative to the sun it's 70,500 mph. There's no air resistance, if you let off the gas you don't just decelerate to zero.
Something that weighs 1 tonne, if you want to stop it could take a lot of fuel or time to run a mono-propellant thruster. These are normally for attitude adjustment because the sort of thrust required to do this task means lugging a Saturn V rocket with you every time you want to "just point the thing at the sun".
Here's an example. Let's say the whole thing carrying the car weighs 1 tonne with all of it's gubbins included. A good thruster can produce 400N, it would take just over a day of running the thruster at full speed to reverse direction and speed completely. That's 70,500 mph to -70,500mph. We're not even including the difficulty or complexity of adding how much fuel you need to lug with you to do it.
That's why when you're in space, you use orbits to change direction and navigating requires complex calculations of working out how close you need to get to planets and moons to work out how fast you're going to be travelling, so how much you'll change direction, orbit entry and exit speeds, and this is just the basics.
The phrase is, "it's not exactly rocket science" for a reason.
Source: I am a rocket scientist.