A machine, put by you on the ground, there and remains. But not for long. If you left her unattended and did not use her for a long time (about 10 minutes), she may disappear.
The server will automatically remove it and move it to Storage (this is not your inventory, and your planetary storage). note, what storage on different planets (and some locations) various. And things, put (or displaced) in the storage area of Thule, will not be available in the storage planet Calypso. It means, what if you quit (have lost) car in the initial area, and moved to the planet Calypso without her, you have to sweat, taking her back.
If the car is missing and you don’t remember, where is she, and in planetary storage or inventory it is not, there is a very simple way, how to find out: open the official website of the game and log in to your account. After authorization, you can see all your items in the game (My Items link on the left). Find the line Valkyrie T1 in your list of items. Opposite it you will see for example such an inscription — Storage (Planet Calypso). It means, that the machine is on planet Calypso in planetary storage. Find the blue Storage terminal on Calypso and get your car.
If the car is forgotten in the initial location (where did you study), then keep in mind, that you will have to visit this area again, and run to Camp Amundsen, and already pick up your car there. Thule entrance at Calypso is close to Port Atlantis Teleport, coordinates 61373, 75006.
After that, how do you pick up the car, you will have to get to the end of the initial area, and move to Calypso again, already with the car.
There is another version of this question, you left your car somewhere nearby, and don’t remember, where is she, but want to ride it now, and wait, until she gets into storage, you don’t want.
There is a Recall All Vehicles team for this. You can find this command in the Action Library book (Y button on keyboard), typing her there in search. After executing this command, all cars, that were on your planet’s surface, will be moved to planetary storage, where can you get them.