Why is the NASA Space Shuttle program ending?

remember the First Mobile phones big bricks and now you have these little phones that have everything on them well the nasa space shuttle program is like the old phones obsolete

First of all, because it is time. The Shuttle is today the oldest flying manned spacecraft. Really. The Soyuz maybe looks still the same as it did in 1986, but was internally constantly upgraded, with the Soyuz TMA-M version being in space for its first flight currently. The Shuttle got the last tiny upgrade around 2000, the last big upgrade was in 1987, and still, the Space Shuttle is full of terribly obsolete technology, that is just very hard to be replaced without designing a completely new Space Shuttle. For example the SRBs still rely on 8086 processors.

Next, the Space Shuttle is a very limited spacecraft itself. Like Soyuz, which is build as taxi to space stations and back, the Space shuttle was made to build stations or other spacecraft. When the NASA budgets cut reduced more and more, all the other fun stuff was thrown away and only the Space Station was left.

Next, the goals changed - the USA want to fly to Moon or Mars (this changes every year), and the Shuttle can't do that, it can't fly further away from Earth than 600 km and can't reenter directly at higher speeds. It is even too expensive for developing new spacecraft while operating the Shuttle at the current budget plans. NASA has the biggest funding of all spaceflight agencies at 18 billion US per year, but still, for what NASA does and what is expected from NASA, this money is nothing. Really. If you would reduce the US Department of Defense Budget by 1%, you could multiply the NASA budget by five. NASA is pretty much the stepchild of all US governments since Johnson. Since Nixon came into power, politicians reduced the budget and increased the demands - when NASA was successful, politicians came around to bath in its light and reduce the budget, when things got tough, NASA was punished by harder budget cuts.

So, if you have no money, despite having a 18 billion budget, you need to save money. You need spacecraft that can be operated for less money and are less limited. The original Augustine plan, that Obama embraced, to give much more money to private companies developing capsules (6 billion for 4 years back then), would have been the most economic, but since the spaceflight experts of congress are total dilettantes, this budget item was reduced to 250 million in total, just enough to hire the five Soyuz capsules that NASA wants to buy for bridging the gap until NASAs own spacecraft can fly.

Space exploration went on before the shuttle was developed and will continue after the shuttle is phased out. In truth, the shuttle was an idea which never lived up to its promise. It proved to be very expensive, very dangerous for the astronauts, and very limited in its potential. We landed on the Moon six times before the work on the shuttle even began, and most of the most exciting space exploration, by robots on Mars, Jupiter, and Saturn, made absolutely no use of the shuttle. The only really useful thing which the shuttle accomplished in its decades of operation was the launching and servicing of the Hubble Space Telescope.

a. the shuttles are aging

b. some of the plans for the shuttles have gone missing over the years

c. the shuttle program is very expensive

d. the technology of the space shuttles is getting out of date

e. NASA wants a more reusable vehicle

the list goes on

The USA has had it's day leading the world .. the 'writing on the wall' was first seen over 50 years ago when the anti-nuclear lobby put paid to the only realistic method of propulsion that could reach the stars (see link) ... ever since then the USA has been playing with fireworks .. Mankind will go to the stars led by China - and with their political system you can be sure that no 'anti-nuclear' nonsense will have any effect ....

The Space Shuttle was only using modified 1970's era technology and had to be phased out eventually using more sophisticated launchers. It was only ever intended by the original designers to be an interim program leading to more sophisticated equipment. I'm surprised they managed to keep it flying for so long. Time to move on...

Because the shuttle is not exploration, the shuttle is a dreary bus ride down the same dusty path

The Space Shuttle has become too expensive to fly, and has proven to be dangerous and difficult to maintain.

Because we don't got no money sweetheart and it is too expensive. No it does not mean it is the end, we are starting a more advanced program but unfortunately we don't have money to start that one. We need to get this economy up first.

it means they're progressing to a new program