# How do the launch controller headsets work?

I have listened to a number of launch countdowns, and especially as they poll for readiness, a large number of people (10-12 or more) need to respond when called on, but the sound quality is excellent.

I seem to live on conference calls for work, and people usually stink at muting/unmuting and background noise is almost always an issue.

I cannot imagine that Mission Control is a quiet place. Yet the countdown net usually has excellent sound quality, everyone responds quickly and on time.

What sort of headset/technology are they using to accomplish this?

• Half the time they don't work. There's usually a big box of them so that you can try to find one that works. – Mark Adler May 7 '15 at 16:13
• @MarkAdler Bummer. When my $3 Blackberry headet fails, I throw it out, grab the next from the bag of 20 I buy each year or two. (Darn Android and iPhone! Maps the single button click to hangup, unlike Blackberries default of Mute). – geoffc May 7 '15 at 16:23 ## 1 Answer There are several factors at work here. Edit: Noise canceling is not used in Mission Control. It is used in the astronauts' headsets, and has been since the 1960s. 1. Headset. Businesses typically use$20 headsets with lousy microphones and no noise cancelling. They have a non-adjustable microphone boom so the mic is always too far away, and tiny, low-quality microphone and speakers.
NASA springs for the good stuff. For the Mercury program, Plantronics supplied headsets for the astronauts. They also supplied headsets for Mission Control, e.g. the MS30 (designed for aviation). These headsets have fully adjustable microphones so the mic position is correct, and the mic itself is directional to reduce the pickup of ambient noise. These sets were designed to work in airplane cockpits, which are very noisy environments and where communications are a matter of life or death.
2. The headset mic isn't always on. Personnel has to use a Push-to-Talk button to trigger the microphone (either a switch somewhere along the mic cable, or a foot pedal).
3. Discipline. Mission Control personnel is a lot better trained (1-3 years before they are allowed to work on an actual mission) than the average office worker, including on the correct use of mute/PUsh-to-Talk and when to speak or not speak.
4. I'd be very surprised if Mission Control were a noisy environment. This is a result of 2: nobody speaks until they absolutely have to. Also, the room is built to dampen all extraneous sounds, and people who do talk do it quietly.
5. What you hear on a NASA launch broadcast is a broadcast commentator outside Mission control, sometimes with some Capcom messages mixed in. In Mission Control, every team has its own comm channel; only the team leader speaks to the launch director. E.g. before the readiness poll there will be an internal poll for each team, and the team leaders gives his Go to the launch director based on that internal poll). Only the team leader is in the Mission Control room, the remainder of his team is in a separate room nearby. There are dozens of comm channels (this page has an image of one comm control station with 48 channels).
People in Mission Control can select more than one channel to listen to (listening to two conversations at the same time is difficult, but it can be done).
• I am jealous. I want one of those headsets now. To be fair, my $3 blackberry headset does a shockingly good noise cancelling job. I used to talk while bike riding with family and friends on it, and it did a surprisingly good job on the noise. – geoffc May 6 '15 at 13:44 • Those headsets are available from Plantronics for about$200. VXi also claim to supply NASA with headsets. – Hobbes May 6 '15 at 19:40
• Another aspect is that unlike typical conference calls, the microphones are neither always-on nor voice-activated. A push-to-talk button must be pressed to make the mic live, much like pilots and air traffic controllers in aviation. So much less ambient noise is present in the signal, and there are fewer spurious activations. – pericynthion May 7 '15 at 1:55
• Discipline is probably a major factor (and this includes the "chain of command" in who talks to whom). Even in amateur radio, you can usually tell quickly who has radio net experience and who doesn't; those who have experience with radio nets have a very different radio discipline than those who are used simply to e.g. a regular two-way telephone, which is a type of traffic that works very poorly on a one-way-at-a-time simplex channel. In my experience this also carries over well to two-way channels like a telephone, especially when there are multiple people involved. – a CVn May 7 '15 at 8:13
• This is all exactly correct, except I've never used or seen a noise-canceling headset in a mission control environment. I don't think it's really necessary there. I use my own noise-canceling headset when flying small aircraft, where that noise environment really warrants it. – Mark Adler May 7 '15 at 16:59