Yep STS-135 is the last one for ISS mission as of now. No more are planned.
Btw does anyone here have interest in watching satellites?
I do that regularly. If you want to see ISS (pray for cloudless sky) you can see it tomorrow evening. It will be very very clear, like a bright star and MOVING!! Easily spotable by naked eye.
At 7:21:48 PM till 7:28:04 PM. But you will get just 2 minutes to spot it.. so dont miss it.
How to see: (this is based on Mumbai)
1) Sync your watch to be accurate up to seconds
2) Reach terrace at 7:10PM and plan the position where you will stand
3) Stand facing exact NORTH, look straight (not towards sky)
4) Raise your left arm parallel to ground (pointing at north) and right arm facing vertically up (pointing sky)
5) Now draw an imaginary line joining tip of both hands. The point at half distance on that line is 45 degrees. This is the spot where u have to look at. So look straight towards north and bend your head backwards by 45 degree looking at that imaginary point.
6) The satellite will pass from that point at around 19:22:30 PM, it shud be easily spotable.
7) Once you spot it the satellite will be going towards center of east and south
8) If you miss point 6) then immediately turn 45 degree right i.e. facing center of north and east and head twisted back by abt 55 degree looking at sky, the satellite will pass from that point at 19:24:57PM. It will come from your left and go to right.
Hope you can spot it!
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Update:
Please note that angles are based on Mumbai, angles/direction vary a lot from place to place (because ISS is very close to earth, just abt 300+ kilometers)
You need lots of patience. It takes 6-7 days to figure out angles. I have tried my best so that you dont have to figure out angles. Unfortunately those angles and direction will work only for people in Mumbai and nearby.