3005: Disposal

|< < Prev Comic #3005 (October 30, 2024) Next > >|

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 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. This is perhaps a reference to Tesla vehicles being quiet and having "vroom" noises pumped into the cabin to satisfy customers.

Transcript

[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.

 add a comment! ⋅  add a topic (use sparingly)! ⋅  refresh comments!

Discussion

That's either a giant Cueball, or a really tiny rocket. Barmar (talk) 23:05, 30 October 2024 (UTC)

It's an Electron? Or maybe Falcon 1? Redacted II (talk) 00:23, 31 October 2024 (UTC)

He must be assigned there by the Range Danger Officer. Elizium23 (talk) 03:05, 31 October 2024 (UTC)

It seems strange to me to see Randall drawing a rocket landing with its engine pointing upward instead of downward, when he traditionally has expressed so much interest in rocket and space physics. It's also notable that the rocket-landing problem was solved by others before SpaceX was considered to have, I bumped into a successful project on a maker site in the past couple years. 172.68.3.71 01:23, 31 October 2024 (UTC)

SpaceX was the first to propulsively land an orbital booster. Redacted II (talk) 01:39, 31 October 2024 (UTC)

The first to propulsively land an orbital booster east of the Mississippi. Elizium23 (talk) 03:04, 31 October 2024 (UTC)

No. Worldwide. List a single orbital rocket booster that propulsively landed before Falcon 9 Flight 20. There aren't any.Redacted II (talk) 12:57, 2 November 2024 (UTC)

(I believe that was a reference to 2901: Geographic Qualifiers, etc.) 172.69.79.183 19:58, 2 November 2024 (UTC)

The extra energy from impacting at high speed ensures the rocket is thoroughly disassembled for maximum packing efficiency. RegularSizedGuy (talk) 06:24, 31 October 2024 (UTC)

I do not think it strange for the rocket engine pointing upwards, I think it funny. It was definitely on purpose. Sebastian --172.68.110.148 08:05, 31 October 2024 (UTC)

There’s a Space Category, and a Kerbal program Category and a Mars Rover Category, why not a Rocket category? I propose on creating one. All in favor? 42.book.addict (talk) 02:33, 31 October 2024 (UTC)

AYE! B for brain (talk) (youtube channel wobsite (supposed to be a blag)) 09:43, 31 October 2024 (UTC)

SQRT(-1) Redacted II (talk) 12:57, 2 November 2024 (UTC)

I remember when businesses would use canisters to hold receipts and send them through vacuum tubes from the checkout to accounting. The canisters would make a "THOOOONK" sound when sucked into the vacuum tubes. I suggest that is why the comic is expecting a "THOOOONK" sound when the rocket enters the disposal site. Rtanenbaum (talk) 11:08, 31 October 2024 (UTC)

We have at least three supplimental jokes in the explination. If we keep this up we're going to need an explainexplainXKCD page. 172.69.135.130 16:00, 31 October 2024 (UTC)

Out of interest, what 'supplimental' jokes would you say these three things are? I see nothing that isn't actually explanation or explainable (if necessary) by the links embed in the text itself. Improvements are always welcome, but maybe we don't necessarily know where there needs to be more honed/expanded description unless you point out where it lacks it. 172.69.194.11 16:49, 31 October 2024 (UTC)

"'...the sound of a canister being sucked into a vacuum tube.'" I don't think 'vacuum tube' means what you think it means. There can not be a "THOOOONK" sound" in a vacuum (no air). Google is all about vacuum electronic devices in (old) amplifiers and computers. The transit tube at the bank is apparently a "pneumatic tube" which makes good sense to me. --PRR (talk) 02:00, 1 November 2024 (UTC)

Point taken (not being the editor who raised this original link) but, like a vacuum cleaner, they can be reduced-pressure tubes (normal atmosphere generally being allowed in behind the capsules, to some degree or other, as they are sucked through to their destinations).

The "thooonk" is more indicative of a system where there's momentary intake of pressure from the outside, as opposed to the "pffffft" that might indicate a momentary leaking out of a high pressure injected behind the 'shuttle capsule' in a positive-pushing pneumatic system.

Also, technically more efficient to partially evacuate tubes ahead of the cannisters than to supply extra air for a 'blowy' version of it, for several reasons (don't build up front-side pressures, or send air the wrong way back up any merging junctions; the (multiple, if necessary) "insertion hatches" are simpler to implement, vs. the one vacuum-ending receiving station; it's more self-cleaning; failures don't generally lead to burst-out pipes scattering debris, at worst generally just a failure to pull anything new through until fixed; it allows for more rapid acceleration but smoothing the end velocity to a managable receiving-speed, rather than necessitating the need to "force the cork all the way out of the bottle" all the way right up to the end). The caveat to this being that it may have an upper limit of length ('repeater' stations may be needed to reboost into a subsequent sucking-stretch) from source node to destination; but the ultimate hard limit to this would be the actual height of the atmosphere (less a proportion, due to all inefficiencies), so not normally a deal-breaker for all practical purposes

Perhaps better described as an "atmospheric" system (c.f. the usual form of atmospheric railway), or at least a "pressure differential" one, than the implication that it's a (possibly closed-loop) compressed-air one, but terminology and implementation details are all rather imprecisely defined anyway. 172.70.160.228 10:22, 1 November 2024 (UTC)