It is explained in the original paper from Sagan:
A Message from Earth
Author(s): Carl Sagan, Linda Salzman Sagan and Frank Drake
Source: Science, New Series, Vol. 175, No. 4024 (Feb. 25, 1972), pp. 881-884
I found a copy on the website of Swarthmore College: link to PDF
On page 2, it is explained:
Those radial lines for which the earth-pulsar distance ...
The holes in the Ozone layer were known as far back as 1957. Scientists just forgot about the earlier report because no one was interested in the issue at the time of discovery.
I encountered this fact while reviewing events recorded in either the NY Times or Omaha Herald (via microfiche) that occurred in my year of birth while in college.
I have not found ...
William Anders who flew on Apollo 8 started to question his Catholic beliefs on his flight. He became an atheist.
The Seattle Times' December 24, 2018 piece With a view from beyond the moon, an astronaut talks religion, politics and possibilities alludes to this:
Ironically, Anders’ six days in space forever altered his own view of his place in the universe....
Most remotely controlled spacecraft and rovers do not use text-based commands. Instead, each command has a unique identifier, a command-specific data structure that contains data specific to that command, and data (e.g. checksums) that confirm the command and data are valid. All of the data are binary rather than text-based.
The Mars rovers use a sequenced ...
For shuttle which used a MIL-STD-1553 bus system for its flight critical functions, a command consisted of some header information (mostly used for validation), the address of the bus terminal unit, card, and channel on the 1553 bus to which the command was to be sent, and a mask to set the desired bits.
The commands were made up of one or more 48 bit words.
New Horizons was extended into 2021, so it will be exploring other Kuiper Belt objects. I don't think it's determined yet which ones. Alan Stern (PI of New Horizons) says the proposals for the next flyby are due January 2022 with decisions made in April 2022.
One source worth reading is the Apollo Experience Report: The Role of Flight Mission Rules in Mission Preparation and Conduct, NASA Tech Note D-7822.
It's way too long to explain here, but a summary is that there is planning of the planning for the planning. Best to simply read the report.