what will happen if we travel in light speed in space shuttle or any other vehicle?

I'll let you know.

We hope that we have invented all these measures that keep people safe in Star Trek.

We can travel the light speed in an out of body experience and Einstein tried to prove it when he died.

I have done it already. OBE's are really gaining worlwide speed.

well we'll be a quantum of energy ,i.e.,

Energy = mass*c^2

First: The acceleration to the speed of light will result in so many G's that human beings would be smashed into a thin goo all over the inside of the space craft. The fastest space craft in existance today only travel at roughly between 25,000 and 50,000 Miles Per "HOUR."

What you propose is to travel at the speed of light which is
186,000 Miles Per "SECOND."

There are 3,600 seconds in one hour.

So that is 186,000 x 3,600 = Miles Per HOUR
which is 669,600,000 Miles Per Hour.

Which is 13,392 times faster than our fastest space craft.
Err-r-r-r...I don't think that is going to happen any time soon.

According to the special theory of relativity, nothing much changes aboard the craft. However, to those left behind, the craft and those aboard appear:
to have their mass --> infinity
Their time processes appear to halt
Their dimensions in the direction of travel appear to shrink

According to Einstein's theory of Relativity, if any thing were able to travel the speed of light-including humans- it too will become a beam of light.
I don't totally understand his theory of relativity. But among other things in the theory, he does say that. But we can't prove it any way.
A better idea would be telleportation. You jump in some thing like a phone booth, type in the destination you want to go, any where in the entire universe and it will telleport you there in about Two Seconds. That would be perfect!

Well, Einstein tells us that time is relative to speed. So, as you travel faster time will 'slow down' in relation to a stationary object. Also, gravity will 'speed up' the flow of time. Which means that if you live high on a mountain you'll actually live longer than if you live at sea level. (The difference will be minute, but there will be a difference. You won't, of course, notice the change.)

At light speed, we believe that time actually stops completely. So if you were to take a trip to Alpha Centauri at the speed of light the trip would seem to be instantaneous, but you'd discover that about 4.37 years have passed back on earth.

However, it's highly unlikely that light speed is even possible. Which means that trips would take only a few seconds or minutes, but would actually take years in 'real time'.

A fun note here, it's theorized that if you could travel faster than the speed of light you'd go BACKWARDS in time. So, technically, you'd arrive at your destination before you left. Wild, huh?

If you achieve light travel by accelerating to it, you would absorb an infinite amount of energy, growing to an infinite mass and making the universe crunch because of your gravity.
But, since there is not enough (enough = infinite) energy in the universe, you cannot accelerate to lightspeed in the first place.