Yes it is possible to travel backward, forward, or even bi-locate with the mind and with the help of some aether-bending materials. There are several ways of doing so but the easiest, or at least most accessible to those not working for the government, just have to do with the right side of our brain and the pineal gland. "Third-eye" type stuff. Very interesting but it does take a lot of meditation practice and prior knowledge of various dimensions... there's such a thing as "Astral Hell" which some may get trapped in while attempting these practices so there are some very complicated aspects to it on a deeper level. Still a fun concept altogether. Anxious to try it someday.
Yes, astronauts on the space station are moving slightly ahead of us I'm time right now, but only by a fraction of a second. They have to keep adjusting their clocks back to stay in sync with controllers on the ground.
Actually the ISS is moving more slowly through time because of it's speed of motion, but it is in microseconds per day and is not noticeable on the human physic. We're all traveling forwards in time. Minute by minute, hour by hour, and I'll see you tomorrow. Jumping forwards through time might be considered possible, if say you could go into some sort of stasis, like a hibernation, or death and then a resurrection. Relativistic travel through time via motion might even be possible but we don't have the technological ability to do that for anything much larger than an atom right now. Traveling or jumping backwards through time does not seem possible though.