Working the launches: the early days

Launch sequencing at the Cape, 1967

I had a correspondence with H. D. McDaniel, a man who worked at the Cape in the early sixties and beyond. He worked in “Launch Sequencing” which is monitoring preparations and activities up to (and including) the launch of a space vehicle.

This is a pretty obscure area. Even as a space buff, I really pay more attention to what happens after a launch. But, in addition to some info from H. D. McDaniel, I’ve got an old book by Werner von Braun in which he discusses launch sequencing. And I happen to have a very old internal newsletter from RCA which discusses it as well. (McDaniel and other in Launch Sequencing worked for RCA.)

So, here’s a short description of what launch sequencing was all about…

von Braun’s View

Launch sequencing is the monitoring (and providing feedback) during the preparation and countdown for a launch. The purpose of this, according to von Braun is:

• assure safety of ground and flight crews, along with protection of equipment, during preparation for launch
• avoid damage to equipment which could come from activating it too early before launch
• enable the flight director to start the launch at the critical moment for the mission…for example, the precise moment best for achieving orbital rendezvous
• synchronize supporting operations, such as ground radar for monitoring

There are emergency procedures and approaches for dealing with anything gone wrong. As one might expect, the most nerve-racking (and, okay, exciting) experiences are when something goes wrong.

Something Went Wrong

As reported in an early post on The Space Buff, a man in launch sequencing told me about the failed launch attempt of Gemini 6. The rocket engines fired, but the vehicle did not take off. For those in launch sequencing, they were under extreme pressure to make a quick recommendation: have the astronauts fire their escape system—saving their lives but canceling the launch and delaying another attempt for weeks. Or, keep the astronauts on the pad, and hope that the rocket doesn’t explode, killing the crew.

My risk-averse nature would be to recommend that the astronauts use the escape system. But launch sequencing favored keeping the Gemini 6 crew in place. That turned out to be the right decision.

H.D. McDaniel described difficulties with a 1960 missile launch:

In 1960 while supporting a Bomarc Launch in Blockhouse 3-4 at T-20 minutes there was an electrical fire near the top of the missile.

All the people on the pad rushed into the blockhouse and secured the blast door. This was one of the oldest Blockhouses on the Cape and only had 4 inch glass windows for protection. The missile continued to burn and the Pad Safety Officer ordered everyone to lie down on the floor.

He tried to activate the emergency water system but it failed.

We hid behind our racks of equipment and peeked out to watch the missile burn. In the next 15 minutes the missile burned all the way to the ground but there were only minor explosions.

In another difficult launch, here’s what happened:

On a Blue Scout launch from complex 18 a programmed automatic holdfire stopped the Sequencer at T-15 seconds, the count would resume when the Test Conductor pressed his proceed switch. The Test Conductor mistakenly hit his holdfire switch and now he didn’t know how to re-start the sequencer.

At T-15 seconds the missile is on internal power, most of the instrumentation recorders are running at high speed and film cameras have been started. If the count is not resumed very soon the test will have to scrub.

The only voice on the audio net is the Test Conductor and he is talking to himself. It is not standard procedure for the Sequencer Operator to instruct the Test Conductor, I would be in big trouble if something went wrong.

I said TC this is Sequencer, press and release your holdfire switch, press and hold your override switch and press sequencer start and we will go. When he did this the count resumed and the launch was successful.

The TC thanked me later but I don’t recall getting an attaboy from anyone else.

The amazing thing is, though, things rarely went wrong. Launching is an extremely complex business, and in his lengthy career, Mr. McDaniel experienced lots of pressure, but few serious problems. The people who worked in launch sequencing are some of the unsung heroes of the early days of space travel.