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− | You can read a brief introduction about this wiki at [[explain xkcd]]. Feel free to sign up for an account and contribute to the wiki! We need explanations for [[:Category:Incomplete explanations|comics]], [[:Category:Characters|characters]], [[:Category:Comics by topic|themes]] and [[:Category:Meta|everything in between]]. If it is referenced in an [[xkcd]] web comic, it should be here. | + | You can read a brief introduction about this wiki at [[explain xkcd]]. Feel free to [[Special:UserLogin/signup|sign up for an account]] and contribute to the wiki! We need explanations for [[:Category:Incomplete explanations|comics]], [[:Category:Characters|characters]], [[:Category:Comics by topic|themes]] and [[:Category:Meta|everything in between]]. If it is referenced in an [[xkcd]] web comic, it should be here. |
− | *If you're new to wikis like this, | + | * If you're new to wikis like this, see [[mw:Help:Editing pages|how to edit wiki pages]]. There's also a handy {{w|Help:Cheatsheet|wikicode cheatsheet}}. |
− | *Discussion about | + | * Discussion about the wiki itself happens at the [[explain xkcd:Community portal|Community portal]]. |
− | *[[List of all comics]] | + | * You can browse the comics from [[List of all comics]] or by navigating the category tree at [[:Category:Comics]]. |
− | *We sell advertising space to pay for our server costs. To learn more, go [[explain xkcd:Advertise Here|here]]. | + | * There are incomplete explanations listed [[:Category:Incomplete explanations|here]]. Feel free to help out by expanding them! |
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Revision as of 20:17, 21 June 2014
Welcome to the explain xkcd wiki!
We have an explanation for all 3 xkcd comics,
and only 6
(0%) are incomplete. Help us finish them!
Latest comic
Disposal |
Title text: We were disappointed that the rocket didn't make a THOOOONK noise when it went into the tube, but we're setting up big loudspeakers for future launches to add the sound effect. |
Explanation
This explanation may be incomplete or incorrect: Created by a MINESHAFT-TARGETING ROCKET - Please change this comment when editing this page. Do NOT delete this tag too soon. |
This comic came out a couple of weeks after the successful first attempt to 'catch' a rocket during Starship flight test 5, based upon SpaceX having an extensive history of bringing rocket stages back to Earth in a controlled manner. Whereas the traditional approach was for such rocketry to allow most of the initial launch-vehicle to be a single-use stage that was effectively destroyed once it had fulfiled its purpose, it has become a developmental aim across much of the commercial side of the industry to introduce as much reusability as possible in the mission hardware to potentially save costs and construction time.
In order to accomplish a successful recovery, expended stages have been given unprecedented ability to control their fall back to the ground, often in a manner that allows them to propulsively halt their descent directly over a prepared landing pad (on land or sea) and settle down softly enough on landing gear to be refurbished and reused (sometimes for more than twenty subsequent missions). For the recent Starship test, the one (and, as of this comic, only) attempt to recover its Super Heavy Booster involved being precisely guided to be caught by the original launch tower; though it is never expected to refly, as a test prototype, it survived the whole process. This is in contrast with plenty of examples, where the landings (or their aftermath) were not quite so successful.
Though SpaceX is the current leader in such an accomplishments, there are other companies who are various degrees along a similar developmental route. Randall claims that he has an organisation that is amongst them, and has achieved the non-trivial feat of being able to direct the discarded rocket stage very precisely, yet without that extra bit of ability to ensure that it doesn’t then subsequently explode. The team has therefore decided to exploit their achievement (to precisely control the rocket) to send it 'safely' into a hole that (barely larger than the rocket's cross-section, and with a sturdy lid directly manhandled by a Cueball employee) allows it to rapidly disassemble in a planned and 'safe' manner. Of course, as a 'compromise', it does not achieve the original aims of recoverability and reusability, yet it also is intrinsically far more complicated than the default option of just letting the hardware generally fall to destruction somewhere in a handy 'empty' down-range area that shouldn't inconvenience anybody.
With the comic depicting the 'disposed' stage as powering downwards, this might explain their lack of success in perfecting any form of intact recovery, as practical examples of this technology tend to spin the craft around to make use of the main thruster(s) for a retrorocket-assisted landing, or at least don't try to counteract the passive deceleration provided by parachutes or other purposeful aerodynamic drag, in order to touch the ground at a survivable velocity.
An explosion in a sealed container is potentially much more dangerous than an explosion in the open, depending on the strength of the container. If the container is strong enough to hold the pressure from the explosion, that pressure could be released in a controlled fashion, safely. But if the container is too weak, it could suffer a catastrophic failure, sending shards of its walls and anything around it flying outwards at high speed. Even if the container is initially strong enough, it could be weakened by repeated explosions, and fail at a random time in the future. As the 'container' is mostly a hole dug into the ground, of indeterminate depth, it might be considered fairly robust in itself, especially if given a reinforced lining. However, this then risks forcing the majority of the resulting explosion up into the lid, which looks strong and heavy yet is closed at least partly by the effort of just one person. It also risks that worker being right next to the track of the descending rocket stage, where they would be at risk of experiencing all kinds of secondary damage, if not being directly in the explosion if they get the timing of the lid-closure wrong. An actual attempt to put a lid on an underground explosion succeeded only in blowing the lid off at such velocity that it was never found.
The title seems to refer to the sound effects of dragging an element into the trash on computers. Or, alternatively, the sound of a canister being sucked into a vacuum tube.
Transcript
This transcript is incomplete. Please help editing it! Thanks. |
- [A two-stage rocket is ascending with a plume of exhaust behind it]
- [The first stage falls off and the second stage ignites]
- [The first stage begins to fall, turned off]
- [The first stage reignites to control trajectory and attitude]
- [The first stage falls toward a large, but barely wider hole with a lid. A Cueball is holding the lid open, which has a hinge attaching it to the ground]
- [Cueball pushes the lid closed]
- Click
- [The first stage, now out of sight, explodes, with Cueball shielding his ear with one hand and flinching away from the loud noise]
- BOOOOM
- [Caption below the panels:]
- Our rockets were good at steering, but we couldn't get them to land without exploding, so we just dug a rocket disposal hole.
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You can read a brief introduction about this wiki at explain xkcd. Feel free to sign up for an account and contribute to the wiki! We need explanations for comics, characters, themes and everything in between. If it is referenced in an xkcd web comic, it should be here.
- If you're new to wikis like this, see how to edit wiki pages. There's also a handy wikicode cheatsheet.
- Discussion about the wiki itself happens at the Community portal.
- You can browse the comics from List of all comics or by navigating the category tree at Category:Comics.
- There are incomplete explanations listed here. Feel free to help out by expanding them!
- We sell advertising space to pay for our server costs. To learn more, go here.
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