Paul Bikle would be laughing at being towed to 42K

Bob- You have to understand the reasoning behind the 42k tow performed by the Perlan project. This is a research program intended to explore the potential of high altitude stratospheric mountain wave. Previous tows have been to around 5,000 and then using the primary wave structure, altitudes up to 40k and 50k (with a World Record at over 52k) have been achieved. However, the transition from 30k to 50k has been troublesome and time consuming. Perlan has a large electrical demand, including telemetry, scientific instrumentation and, most importantly, life support. Battery capacity has been increased, but with eight hour flights planned on the way to the targeted 90k, reserve electrical capacity could drop below what is considered necessary to provide a margin of safety for essential systems. The 42k tows are intended to get the aircraft to the target wave height so that more efficient use of time (and daylight) can possibly help Perlan reach the goal of flight at 90k. Perhaps some rare condition will develop that can allow for a "low tow" and then climb into the upper atmosphere in the Polar Vortex, but for now, high tows behind the Egrett are deemed a more efficient use of resources to achieve the mission goals.

I am not connected with the Perlan Project, except as being friends with many of the participants, so any errors in the above explanation are mine alone. Best of luck to Perlan, and congratulations on the 62k altitude flight!