"In order to make any intelligent plans for implementing the new Space Initiative, we need to know how bad the space debris problem will be 20 to 50 years in the future. If it will not be possible to use LEO for prolonged assembly or parking of interplanetary vehicles, we will have to shift such operations at another site such as the Earth-Moon L-1 point. The Congress or the Aldridge Commission needs to force NASA to conduct a serious study of the future evolution of the orbital debris population and make specific predictions about what limitations this hazard will present to the manned missions proposed in the new Space Initiative."
By Jeffrey F. Bell :
http://www.spacedaily.com/news/spacetravel-04i.html