After decades of rocketlaunches what is the need for a human voice to countdown the launch. Apart from the thrill for the observer ie if it is broadcast, why cant they have an alternate way to get to point zero when th rocket launches.
What alternate way is there to get to zero aside from going through all the other numbers?
Seriously, the reason they have countdowns is because lots of stuff has to happen in a specific sequence. Nowadays most of that is controlled automatically by a launch sequencer computer (with the final tasks handled by a computer on the vehicle itself) but you still need to keep everyone apprised of where you are in the countdown so they can be checking that everything is working how it’s supposed to.
Plus it’s fun.
I’ve read (but can’t verify) that it was first done in the movies for effect and later copied by the space program.
The human voiced last few seconds countdown annoys me greatly. It serves no useful purpose in a modern launch - it isn’t actually being used to sequence the launch steps, that is the responsibility of the rocket itself long before the 10 second point. It does serve to let the launch controllers know where in the sequence things are, so they can keep track, but really, it isn’t a big deal. Worse, many telecasts add the voice of a booming professional announcer that drowns out the sound of the actual launch.
The launch director or some other human will be calling out the countdown at earlier stages as they direct the non-automated actions for the launch. Part of this includes launch holds - where the countdown clock stops for periods of time to provide slack for any unforeseen activity to be completed. So you will hear calls for preprogrammed countdown holds and resumption of the countdown clock. But the last 30 seconds of so of the countdown is automatic, as it requires sequencing of actions at a precision that humans can’t match, and detection of faults at speeds humans can’t match.
If nothing else, it alerts the photographers.
Hey. We just got rockets that land on their tails, as God and Robert Heinlein intended. Don’t take the countdown away from us. I want my first space trip to be completely traditional, from beginning to end.
Rockets are not as forgiving as, say, airliners. Getting it ready for launch isn’t just a matter of checking off every item on a checklist. There are many things that can’t happen too early - e.g. if you disconnect the umbilical cables too early, the onboard battery may run out too soon. Turn on certain systems too early and they overheat. Other things need to be done early enough - e.g. things that need time to stabilize or be tested after they are turned on. So the checklists and procedures are all written in terms of “T minus” time. It makes sense for the countdown to be on speakers because it’s one piece of information everyone on the team needs to be aware of.
Even in the last minute of countdown, human beings are still monitoring the situation and making sure things are behaving as expected. It’s useful to have the verbal countdown on speakers so they can keep an eye on instrument readings without having to glance up at the countdown clock every few seconds.
I work on sounding rockets (sub-orbital science rockets), and on those, countdown isn’t even automated. We look through the countdown sheet, monitor the situation and push the buttons at the right time.
This. While computers are controlling the launch sequence things can still theoretically go wrong. Computers components can fail and software can be sabotaged. Humans are monitoring things closely to make sure everything is happening as expected. One small and seemingly insignificant change in the launch sequence can cause one large explosion.
Now if you’re talking about the voiceover added by the various media just to increase drama I agree we can lose that, but the actual countdown still has a purpose. It ensures everyone involved knows exactly where they are in the sequence.
And sometimes kick the controller box when the T=0 button doesn’t work right the first time.
But not *too *traditional. It’s traditional that first flights explode someplace along the way.
Maybe they do it for the spectators rather than the experts at work.
But the spectators may include media and so on, and the rocket experts want them to get things right and enjoy the day.
Part of the question is “why not just have a launch button ?”. Its my understanding that there is stuff going on as they fill up reservoirs and bring gas pressures up to take off pressure… all these fuel reservoirs that were left empty or low pressure until the last moment … maybe because there’s always some sort of leak, as its an engineering challenge to get metal parts sealed perfectly… Theres all sort of reasons that is bad, such as expense, and some of the leaking gas is highly toxic. but they keep the leaking to a minimum and launch as soon as its come up to ready at time zero, and if there is a delay, due to a crew member having a sneezing fit or something, it can mean a launch cancellation … because they are worried that the leaks had made it dangerous, no delay is permitted after the some point. So at some point in getting ready, they are locked in to launch N seconds later… OR pressing “Delay” would mean the same as cancel and reset, even a total remove and dissassemble rocket reset… So there is the count down time there.
Courtesy of the 1929 German movie “Frau im Mond” (“A woman on the Moon”), written and directed by Fritz Lang. From the relevant Wikipedia article:
"The basics of rocket travel were presented to a mass audience for the first time by this film, including the use of a multi-stage rocket. The film was shot between October 1928 and June 1929 at the UFA studios in Neubabelsberg near Berlin.
<…>
as launch approaches, the launch team counts down the seconds from ten to zero (“now” was used for zero), and Woman in the Moon is often cited as the first occurrence of the “countdown to zero” before a rocket launch."
Herman Oberth (rocket scientist) was scientific advisor for the film.
Here you have a couple of videoclips (switch off the sound in your computer; I have been unable to find short clips of the relevant portions of this film that are not marred by completely idiotic techno-music playing in the background).
Taking the rocket to the launch pad: https://youtu.be/M3redWFC758
The launch itself: https://youtu.be/uQlwhG76P9A
In a way, I find it charming that they say that an acceleration of slightly more than 4g during take off would be immediately lethal to the human organism ^.^
But, really, the movie is rather impressive from a technical/engineering point of view, especially given that it is from 1929, almost 90 years ago (from the plot/story point of view, well… it is a rather unimpressive melodrama 
)
Yes, the voice doing the countdown on the early American space shots is the NASA media-relations guy, doing a count down because he thought it was a good idea. Just like a countdown to midnight on New Years eve.
The actual rocket control guys were to busy doing rocket-launch things to be either counting down or talking to the radio/TV audience at that time. Even if they had thought it was a good idea. And I think that even in the days of radio, big organisations like NASA were to media-savy to do that.
OP, if a countdown wasn’t done, what do you think should be done instead?
“SURPRISE! I hope you weren’t too startled by the engines lighting off while you weren’t looking! The bathroom’s over thataway, but I doubt we keep fresh underwear there.”
Rocket launches aren’t the only thing with the loud imminent public warning. If you do demolitions or other work with explosives, you call “fire in the hole” and maybe sound sirens. Because surprising people with the ignition of a loud, energetic, and possibly dangerous event is a terrible idea.
although Die Frau im Mond was the first use of the CountDOWN, you should know that it was preceded by the CountUP, in which the launch occurred after the announcer, having starred at one, counted up to a pre-arranged number (ten, I think).
This was courtesy of Jules Verne, who used this method for timing and announcing the launch of the first manned trip to the moon inFrom the Earth to the Moon (1965)
Fritz Lang and Thea von Harbou just reversed the direction of the count 54 years later, having it end more dramatically at zero
As with Metropolis, the Fritz Lang film was based on a book written by his wife Thea von Harbou, also called Die Frau im Mond. Apparently it was translated and published in English back in 1977, but I’ve never read it. I wonder if the countdown is used in the book, released a year before the movie.
The “rocket control guys” obviously used the countdown clock to manage their operations. You can see the digital countdown clock in the front center of the control room. And I would expect that someone was reading it out loud on the intercom channel which most engineers were listening to. Not constantly, but more frequently towards the end. In the sounding rocket launches I’ve been part of, the controller reads it out every minute or so, and maybe every 10 seconds in the last minute, and every second for the last 10 seconds or so.
1865
Damn. Could’ve sworn I was around for that one.
Note there are two different control rooms and separate groups of engineers involved in US manned spacecraft launches. The Launch Control Center (LCC) in Florida controls the vehicle through the countdown, launch, and until the tower is cleared.
Here is a firing room in the Florida LCC during Apollo:https://www.nasa.gov/sites/default/files/1969-10-29.jpg
And during a shuttle launch: https://www.nasa.gov/sites/default/files/firingroom-fisheye.jpg
After the tower is cleared, control is handed over to Houston where different engineers handle the rest of the flight.
Apollo: https://writingwithrobin.files.wordpress.com/2014/12/s69-34039.jpg
Shuttle: https://www.nasa.gov/images/content/354233main_jsc2009e121511_hires.jpg
So the group most interested in the countdown would be the LCC staff in Florida since they are responsible for launching the vehicle and controlling it the first few seconds. However I doubt they are listening to the NASA public affairs officer voice a countdown. They are all monitoring their individual telemetry screens which probably have a countdown clock on each of them. Each launch controller is on a series of voice loops with the people he most needs to clearly hear. The last thing he’d want is a critical communication splattered with some PR verbiage about the launch.
At about 11:10 into this video you can see the Florida Launch Director and others watching STS-135 the last shuttle launch: https://youtu.be/TnvTB-tZtjg?t=665
At 06:00 into this video you can hear what is apparently a shared voice loop that all Houston flight controllers hear on the launch of STS-133. It is very sparse and brief. This only makes sense because they are all watching screens that tell them the status of the launch: https://youtu.be/jJXFlwylHwo?t=360
History of NASA Launch Control Center in Florida: https://www.youtube.com/watch?v=VzJ2UNLiSYU