In the "faster, better, cheaper" era in the mid-1990s, NASA leaders pushed for a low-cost space telescope. The result was the NGST concept, with an 8-meter aperture and located at L2, roughly estimated to cost US$500 million. In 1997, NASA worked with the Goddard Space Flight Center, Ball Aerospace & Technologies, and TRW to conduct technical requirement and cost studies, and in 1999 selected Lockheed Martin and TRW for preliminary concept studies. Launch was at that time planned for 2007, but the launch date has subsequently been pushed back many times (see table further down).