Editing AS-201 (section)

==Preparation for flight==
[[File:Saturn Apollo Program (6522248).jpg|thumb|S-IB-1 undergoing a full-duration static firing at [[Marshall Space Flight Center|MSFC]] on April 13, 1965]]
[[File:651220Saturn1Bpropellantloadingtests.jpg|thumb|S-IB-1 undergoing propellant tests for AS-201 on December 20, 1965]]
The first piece of the rocket to arrive at the Cape was the S-IB stage on August 14, 1965, by the barge ''Promise''. It was built by Chrysler and featured eight H-1 engines built by Rocketdyne. The S-IVB second stage arrived next on September 18. The Instrument Unit that would control the launch vehicle arrived October 22, the command module arrived three days later and the service module on October 27.<ref name="moonport">{{cite report|title=Moonport - A History of Apollo Launch Facilities and Operations |first1=Charles D. |last1=Benson |first2=William Barnaby |last2=Faherty |date=1978 |url=https://www.google.com/books/edition/Moonport/BEYCAAAAIAAJ?hl=en&gbpv=1&bsq=barge%20Promise |publisher=NASA |access-date=May 14, 2025}}</ref>{{rp|368-369}}

The first stage was erected at the pad soon after arriving at [[Cape Canaveral Air Force Station|Cape Kennedy]]. The second stage joined it on October 1. After fixing some problems in the Instrument Unit it was mated to the S-IVB on October 25. The CSM was mated on December 26.<ref name="moonport"/>{{rp|369}}

The first problem encountered by NASA came on October 7. The [[RCA 110A]] computer which would test the rocket and thus, automating the process, was ten days behind schedule meaning that it would not be at the Cape before November 1. This meant that by the middle of October little could be done at the pad. When the computer finally did arrive it continued to have problems with the punch cards and also the capacitors that did not operate well under a protective coating. In the end however the testing of the launch vehicle was still on schedule.<ref name="moonport"/>{{rp|349-352, 372}}

Testing was running around the clock during December. Technicians were testing the CSM's fuel systems during the day and the testing was running on the rocket at night.

There was even an instance of a variant of the [[Y2K bug]] in the computer. As it ran past midnight, when the time changed from 2400 to 0001 the computer could not handle it and "turned into a pumpkin" according to an interview with Frank Bryan, a [[Kennedy Space Center]] Launch Vehicle Operations Engineering staff member.<ref name="moonport"/>{{rp|373}}
[[File:APOLLO SPACECRAFT 009 - SATURN 1B 201 - ON PAD - COMPLEX 34 - CAPE (S66-20410).jpg|thumb|Saturn 1B countdown demonstration at [[LC 34]] on February 6, 1966]]
In the end the testing regimen slowly completed and the plugs-out tests were completed proving that the rocket could function by itself.