So light travels 5,869,713,600,000 miles in a year  In four years it would travel 23,478,854,400,000 miles.   It would take the Space shuttle traveling an average of 18,000 mph 1,304,380,800 hours to reach that distance, which is 54,349,200 days or 148,800 years. 2 people found this useful. 4 Jays.
http://www.answers.com/Q/How_long_would_it_take_to_travel_1_light-year_from_earth_and_1_light-year_back
I did a bit of a calculation and came up with this, I hope I got it right. Light travels 9,454,254,955,488 Km per year. Spacecraft travels at around 50,000 Km per hour 438,000,000 Km per year. Just over 21,585 years to cover the distance. Here's some refs. for a bit of thought.
http://www.sciforums.com/threads/how-long-would-it-take-to-travel-a-light-year.4742/
Travelling at a constant speed of 240,000 km/hr, Helios 2 would take 19,000 years (or over 600 generations) to travel 4.3 light years. Again, these speeds are prohibitively slow for any quick forms of transportation to the stars.
http://www.universetoday.com/15403/how-long-would-it-take-to-travel-to-the-nearest-star/
This way you'll have zero speed when you get there. So: for the first half lightyear, s (distance) = (a/2) * t^2 = 5 t^2. So when you know s in meters (c=299792458m/s), divide by 5, take the square root and there's your time in seconds. There's half the journey; double it for the whole one. None of this takes time dilation into account, of course.
http://www.sciforums.com/threads/how-long-would-it-take-to-travel-a-light-year.4742/
In April, I examined how long it takes to travel to the Moon. We took the fast-track with New Horizons Pluto mission, powering past Earth’s only natural satellite in a mere eight hours and 35 minutes. We also had the leisurely ion drive-propelled SMART-1 mission that trundled its way to the Moon for 13 months.
http://www.universetoday.com/15403/how-long-would-it-take-to-travel-to-the-nearest-star/
But how far exactly is a light-year? Light travels 186,000 miles per second. There are 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day, and 365 days in a year. Multiply these together to get 31,500,000 seconds in a year.
http://school.discoveryeducation.com/schooladventures/universe/itsawesome/lightyears/
The distance of a light year. How long would it take the space shuttle to go one light-year? The shuttle orbits the Earth at about 5 miles per second (18,000 mph). Light travels at 186,000 miles per second, which is about 37,200 times faster than the shuttle. So the shuttle would need about 37,200 years to go one light-year.
http://school.discoveryeducation.com/schooladventures/universe/itsawesome/lightyears/
If traveling at the speed of light, it will take 17,000 years to  travel 17,000 light years. One light year is about  5,865,696,000,000 miles.
http://www.answers.com/Q/How_long_would_it_take_to_travel_1_light-year_from_earth_and_1_light-year_back
1 1 light-year is 5.8 trillion miles and the maximum speed of a NASA Space Shuttle is 17,500 miles per hour. 2  The fastest unmanned space craft traveled 157,000 mph. 3  At that rate, there and back would take only 8,500 earth years. 4  So if you were a Mesopotamian farmer in 6,500 BC, you'd be getting home right about now.
http://www.answers.com/Q/How_long_would_it_take_to_travel_1_light-year_from_earth_and_1_light-year_back
-- At 1 million miles per hour, it takes about 671 years. -- At 60 miles per hour, it takes about 11.2 million years. A light year is the distance that light will travel in one year in a vacuum. The speed of light is 186,000 miles per second. So, light will travel about 5.8 trillion miles in one year. Now, to answer the question. The answer depends on how fast you are traveling. If you were in a space ship travelling 99.9999% the speed of light, it would take you about a year to travel a light year.
http://www.answers.com/Q/How_long_will_it_take_to_travel_a_light_year
how long would it take to travel one light year
It would take 37,200 years to travel one light year.