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For more context, all (edit: American!) rockets for decades have had onboard self destruct systems and a "Range Safety Officer" on the ground whose entire job i
by Phlarp 10y ago
For more context, all (edit: American!) rockets for decades have had onboard self destruct systems and a "Range Safety Officer" on the ground whose entire job is to determine if and when to deploy this self destruct system.
The cruise missile scenario is highly unlikely as the rocket itself would be destroyed soon after leaving its intended trajectory.
- cstross 10y agoNot all rockets: https://en.wikipedia.org/wiki/Intelsat_708 https://en.wikipedia.org/wiki/Intelsat_708 (China, CZ-3B, Intelsat 708 payload, the launcher flew off-course and crashed on a village in 1996: by some estimates 200-500 civilians were killed.)
- ygra 10y agoAll rockets launched in the US have to have one, though :-)
- dalke 10y agoThat links to http://www.thespacereview.com/article/2323/1 http://www.thespacereview.com/article/2323/1 where one of the comments is: > Like Russian vehicles, there is no flight termination system that receives ground commands onboard Chinese launch vehicles. Only US and ESA launch sites have such a system. Correction, Falcon 1 did not have such a system for launching on Kwaj.
- dogma1138 10y agoThat's because usually the US and ESA/France launch from densely populated areas. The launch pad at the Kennedy Space Center/CC is effectively about 50 mile from downtown Orlando, Baikonur is in the middle of nowhere.
- T0T0R0 10y agoOkay, rockets that can go very high, can still crash very far away. An unpredictable, malfunctioning rocket could still million-to-one itself onto a school bus filled with children, halfway across a continent.
- dalke 10y agoPhlarp's original comment was about 'a "Range Safety Officer" on the ground whose entire job is to determine if and when to deploy this self destruct system.' The text I quoted implies there is an onboard flight termination system, even if there is no Range Safety Officer who can send external commands. FWIW, a part from an exploded rocket, like the engine, could still destroy a school bus filled with children. The odds are very hard to estimate, and made more complicated in that there are few failure modes where a rocket failure halfway across a continent, at supersonic speeds, would reach the ground without breaking long before.
- T0T0R0 10y agoCongratulations on replying to me. I'm sure you're feeling good about it. I just wanted to let your know that I noticed, and feel special too.
- jsprogrammer 10y agoHow often is the self-destruct mechanism tested?
- akiselev 10y agoVery often. Air Force range safety guidelines require a million dollar flight termination system and most of that cost is testing and quality control. I don't have an authoritative list of all flight terminations but it happens at least once every few years whenever a rocket fails to follow the set flight path.
- Phlarp 10y agoI also have to suspect things like isolated, dedicated and redundant comm links with the flight termination system are part of these guidelines. Perhaps even a "dead man's switch" that terminates the flight if this separate communication system loses signal at some point. (Even if this means a costly false positive or two~)
- Animats 10y agoFor the Space Shuttle, the flight termination system had two huge 10KW transmitters to send the signal. That would get through despite damaged receiving antennas, noise, or jamming.
- dingo_bat 10y ago10kW? That sounds like a lot of energy to dump into air. Certainly unhealthy for operators or people near the tx site.
- makomk 10y agoLess than the typical TV or FM broadcast tower, and remember there's a lot of empty space around the launch sites. Even ham radio operators in the US can run at 1.5kW peak.
- 10y ago
- fudged71 10y agoImagine how stressful that job would be when astronauts are the payload!
- mandevil 10y agoThere were no self-destruct systems on the shuttle orbiter, though there were on the solid rocket boosters and external fuel tank. They were used only once, on the Space Shuttle Challenger after the orbiter broke up, but the SRB's were still burning in an uncontrolled manner.
- TrevorJ 10y agoYeah SRB's don't really have an off switch unfortunately.
- Coincoin 10y agoDon't worry, unlike the space shuttle, rockets have escape mechanisms. In that specific case, the astronauts would probably have survived as the emergency rocket thingies would have fired and evacuated them far from the explosion before it could reach the capsule.
- peletiah 10y agoHow are these triggered? Motion-sensors?
- deleted 10y ago[deleted]
- robryk 10y agoNit: flight termination system does not cause the rocket to magically vanish. It will still continue on its current trajectory and impact Earth somewhere. It just causes the rocket to stop thrusting and, IIRC, disperses the fuel/oxidizer so that we don't end up with large quantities of fuel/oxidizer in a small area on ground.
- ygra 10y agoIndeed, all it does is break up the rocket. Depending on when it happens during the launch we might still end up with a fireball near the ground (unlikely to be near anything inhabited, though, as there's a lot of free space around launch sites) or with a quickly disintegrating rocket because it's already at high speeds. There will still be debris, of course, but I guess the reasoning is that it's preferable to have relatively small debris, than one large piece of exploding debris.
- robryk 10y agoSize of debris is not that important: lots of small pieces will cause a similar amount of damage as the same mass in a large piece. Two important roles of flight termination are: 1. Cause the rocket to stop thrusting (and thus prevent it from thrusting out of range safety exclusion zone). 2. Cause the propellant tanks to be destroyed. This prevents the propellants from causing a large explosion on the ground (when the tanks hit the ground) in preference to a conflagration in the air.