Final answer:
The first real textbook on space was a collaborative effort by several influential scientists and astronomers, including Carl Sagan and Georges Lemaître.
Step-by-step explanation:
The first real textbook on space was not written by a single author, but rather, it was a collaborative effort by several influential scientists and astronomers. One of the earliest and most notable contributors to the field of astronomy was Carl Sagan, who wrote the book Cosmos, which provided a classic overview of astronomy. Another important figure in the field was Georges Lemaître, who played a key role in the development of the Hubble-Lemaitre law. However, it is important to note that the exact first textbook on space is not explicitly mentioned in the provided information.