Three years <a href=" http://www.janvandenbroekfotografie.nl/index.php/how-much-does-levonorgestrel-tablets-cost.pdf#amorous ">purchase levlen online</a> The mission is still in the very early planning stages and NASA will host a technical workshop at the end of September to discuss potential approaches. The asteroid mission is one step in the agency’s strategy to send humans to Mars in the 2030s.