AS-201

AS-201 (or SA-201) was the first flight of the Saturn IB launch vehicle.

Objectives

This was not only the first flight of the Saturn IB rocket but the first real flight of a production Command and Service Module (CSM-009). It was a Block I version though, whereas all manned missions would end up using the Block II.

The Saturn IB was the uprated version of the Saturn I rocket which had already flown ten times in an earlier part of the Apollo program. The main difference between the rockets was that the first stage engines produced 7.1 million newtons as opposed to 5.8 million newtons on the Saturn I. It also featured a new second stage (the S-IVB, which was also used as the third stage of the Saturn V). The S-IVB could be restarted in space and featured a new hydrogen-burning J-2 engine (which would also be used on the S-II second stage of the Saturn V).

The mission profile was for the first and second stages of the rocket to launch the spacecraft into a high ballistic trajectory. The Service Module engine would then fire to accelerate the spacecraft to a high-speed reentry to test the heat shield.

Preparing for the flight

The first piece of the rocket to arrive at the Cape was the S-IB stage on 14 August 1965 by the barge "Promise". This was built by Chrysler and featured eight H-1 engines built by Rocketdyne. The S-IVB second stage arrived next on 18 September. The Instrument Unit that would control the launch vehicle arrived 22 October, the Command Module arrived three days later and the Service Module on 27 October.

The first stage was erected at the pad soon after arriving at Cape Canaveral. The second stage joined it on 1 October. After fixing some problems in the Instrument Unit it was mated to the S-IVB on 25 October. The CSM was mated on 26 December.

The first problem encountered by NASA came on 7 October. 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 1 November. 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 like operating under a protective coating. In the end however the testing of the launch vehicle was still on schedule.

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.

In the end the testing regime slowly completed and the plugs-out tests were completed proving that the rocket could function by itself.

Flight

Launch attempt

The first launch attempt on 25 February 1966 looked as though it would be the real thing. As always there were several small delays, but when the pressure in one of the fuel tanks in the S-IVB fell below the allowed limits, the onboard computer aborted the launch with 4 seconds left.

The problem was easily fixable but it was thought that it could not be done in the launch window. However some members of the launch team thought that it could and convinced the managers to let them run a simulated launch and 150 seconds of flight to show that the rocket could operate with the lower pressure in the fuel tank. They found it could be and the launch was "de-scrubbed".

Flight

Finally, after months of delays and problems, the first flight of the Saturn IB lifted off from Pad 34. The first stage worked perfectly lifting the rocket to 57 km, when the S-IVB took over and lifted the spacecraft to 425 km. The CSM separated and continued upwards to 488 km.

The CSM then fired its own rocket to accelerate the spacecraft towards Earth. The first burn lasted for 184 seconds. It then fired ten seconds later for ten seconds. This proved that the engine could restart in space, a crucial part of any manned flight to the moon.

It entered the atmosphere traveling 8300 m/s. It splashed down only 37 minutes after launch, 72 km from the planned touch down point, and was on board the USS "Boxer" two hours later.

Problems

There were three serious problems found on the flight. The Service Module engine only worked properly for 80 seconds, interrupted by the presence of helium gas in the combustion chamber. Helium was used to pressurize the fuel tanks but should not have been in the combustion chamber. This was caused by a break in an oxidizer line that allowed helium to mix with the oxidizer.

The second problem was that the electrical system failed causing the command module to lose control ability during reentry. Lastly, measurements that were meant to be taken during reentry failed due to a short circuit. Both of these problems were found to be due to bad wiring, and were easily fixed.

Capsule location

After the flight the capsule was also used for drop tests at White Sands Missile Range. It is now on display at the Strategic Air and Space Museum, Ashland, Nebraska.

External links

* [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750065090_1975065090.pdf Postlaunch report for mission AS-201 (Apollo spacecraft 009) - May 1966 NASA (PDF format)]
*http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=APST201
*Moonport: A History of Apollo Launch Facilities and Operations http://www.hq.nasa.gov/office/pao/History/SP-4204/cover.html
*Chariots for Apollo: A History of Manned Lunar Spacecraft http://www.hq.nasa.gov/office/pao/History/SP-4205/cover.html
*Strategic Air & Space Museum: http://www.strategicairandspace.com/home.html