"This category [science fiction] excludes rocket ships that make U-turns, serpent men of Neptune that lust after human maidens, and stories by authors who flunked their Boy Scout merit badge tests in descriptive astronomy."
- Robert Heinlein

Here's another early reference from around 1952 from the RAND corporation:

Work that began at RAND in 1952 led to the solution of the critical problem of nose-cone overheating during the reentry of a space vehicle into the earth's atmosphere. Along with the use of a blunt nose cone to dissipate heat, RAND's studies suggested the use of ablation cooling.14 The effective use of these methods was not only essential to the space program but also critical to the success of the intercontinental missile.
(From Air Force Space and Missile Pioneers.)

The US Centennial of Flight Commission has this to say:

Although various people, including Wernher von Braun and experts at Douglas Aircraft Company's Project RAND, had studied spaceflight during the 1940s, nobody began thinking about how a vehicle would actually return from space until the early 1950s. The few who did, like von Braun, realized that probably the best way to do it was to build a very big vehicle and circulate a fluid through its skin to soak up the heat of reentry... Clearly the problem of reentry to Earth's atmosphere was a significant challenge for the early spaceflight researchers, as they considered how best to overcome the heat generated by friction as a spacecraft slowed in the atmosphere. While most proposals for satellites between 1946 and 1957 avoided the difficult problem of reentry, some researchers tackled the problem with determination.
(From Early Reentry Vehicles: Blunt Bodies and Ablatives

Something similar to this was designed by Goodyear in the seventies- the concept was that this was an inflatable "escape pod" that could be used in emergencies. Space suits were required.

Airmat