Voyager 1 Completes Tricky Thruster Reconfiguration

September 11, 2024 by Maya Posch 34 Comments

After 47 years it’s little wonder that the hydrazine-powered thrusters of the Voyager 1, used to orient the spacecraft in such a way that its 3.7 meter (12 foot) diameter antenna always points back towards Earth, are getting somewhat clogged up. As a result, the team has now switched back to the thrusters which they originally retired back in 2018. The Voyager spacecraft each have three sets (branches) of thrusters. Two sets were originally intended for attitude propulsion, and one for trajectory correction maneuvers, but since leaving the Solar System many years ago, Voyager 1’s navigational needs have become more basic, allowing all three sets to be used effectively interchangeably.

The first set was used until 2002, when clogging of the fuel tubes was detected with silicon dioxide from an aging rubber diaphragm in the fuel tank. The second set of attitude propulsion thrusters was subsequently used until 2018, until clogging caused the team to switch to the third and final set. It is this last set that is now more clogged then the second set, with the fuel tube opening reduced from about 0.25 mm to 0.035 mm. Unlike a few decades ago, the spacecraft is much colder due energy-conserving methods, complicating the switching of thruster sets. Switching on a cold thruster set could damage it, so it had to be warmed up first with its thruster heaters.

The conundrum was where to temporarily borrow power from, as turning off one of the science instruments might be enough to not have it come back online. Ultimately a main heater was turned off for an hour, allowing the thruster swap to take place and allowing Voyager 1 to breathe a bit more freely for now.

Compared to the recent scare involving Voyager 1 where we thought that its computer systems might have died, this matter probably feels more routine to the team in charge, but with a spacecraft that’s the furthest removed man-made spacecraft in outer space, nothing is ever truly routine.

A Look Inside A DIY Rocket Motor

September 11, 2024 by Dan Maloney 6 Comments

[Joe Barnard] made a solid propellant rocket motor, and as one does in such situations, he put it through its paces on the test stand. The video below is not about the test, nor is it about the motor’s construction. Rather, it’s a deconstruction of the remains of the motor in order to better understand its design, and it’s pretty interesting stuff.

Somewhere along the way, [Joe], aka “BPS.Space” on YouTube, transitioned from enthusiastic model rocketeer to full-fledged missile-man, and in the process stepped up his motor game considerably. The motor that goes under the knife — or rather, the bandsaw — in this video is his “Simplex V2,” a completely DIY build of [Joe]’s design. For scale, the casing is made from a 6″ (15 cm) diameter piece of aluminum tubing over a meter in length, with a machined aluminum forward closure and a composite nozzle assembly. This is a pretty serious piece of engineering.

The closure and the nozzle are the focus of the video, which makes sense since that’s where most of the action takes place. To understand what happened during the test, [Joe] lopped them off and cut them roughly in half longitudinally. The nozzle throat, which was machined from a slug of graphite, fared remarkably well during the test, accumulating only a little slag from the propellant, a combination of powdered aluminum, ammonium perchlorate, and HTBP resin. The lower part of the nozzle, made from phenolic-impregnated linen, did pretty well too, building up a pyrolyzed layer that acted much like a space capsule’s ablative heat shield would. The forward closure, whose sole job is to contain the inferno and direct the exhaust anywhere but up, took more of a beating but stood up to the challenge. Especially interesting was the state of the O-rings and the way that the igniter interfaced with the closure.

Post mortems like these are valuable teaching tools, and while it must be heartbreaking to destroy something you put so much work into, you can’t improve what you can’t measure. Hats off to [Joe] for the peek inside his world. Continue reading “A Look Inside A DIY Rocket Motor” →

The Apple Watch As An Ammeter

September 10, 2024 by Jenny List 3 Comments

Your shiny new personal electronic device is likely to be designed solely as an app platform to run the products of faceless corporations, so the story goes, and therefore has an ever smaller hacking potential. Perhaps that view is needlessly pessimistic, because here’s [JP3141] with an example that goes against the grain. It’s an Apple Watch, being used as an ammeter. How it does that comes as the result of a delicious piece of lateral thinking.

Like many mobile devices, the device comes with a magnetometer. This serves as an electronic compass, but it’s also as its name might suggest, an instrument for sensing magnetic fields in three axes. With a 3D printed bobbin that slides over the watch, and a few turns of wire, it can sense the magnetic field created by the current, and a measurement can be derived from it. The software on the watch is only a simple proof of concept as yet, but it applies some fairly understandable high-school physics to provide a useful if unexpected measure of current.

We’re surprised to see just how many times the Apple Watch has appeared on these pages, but scanning past projects it was a cosmetic one which caught our eye. Who wouldn’t want a tiny Mac Classic!

Cruise Ship-Lengthening Surgery: All The Cool Companies Are Doing It

September 10, 2024 by Maya Posch 56 Comments

Sliding in an extra slice of cruise ship to lengthen it. (Credit: Silversea cruises)

The number of people going on cruises keeps rising year over year, with the number passengers carried increasing from just over 3.7 million in 1990 to well over 28 million in 2023. This has meant an increasing demand for more and also much larger cruise ships, which has led to an interesting phenomenon where it has become more economical to chop up an existing cruise ship and put in an extra slice to add many meters to each deck. This makes intuitively sense, as the segment added is fairly ‘dumb’, with no engine room, control systems, but mostly more rooms and cabins.

The current top-of-the-line cruise ship experience is exemplified by the Icon class that’s being constructed for the Royal Caribbean Group. The first in this line is the Icon of the Seas, which is the largest cruise ship in the world with a length of 364.75 meters and a gross tonnage of 248,663. All of this cost €1.86 billion and over two years of construction time, compared to around $80 million and a few months in the drydock. When combined with a scheduled maintenance period in the drydock, this ‘Jumboization’ process can be considered to be a great deal that gives existing cruise ships a new lease on life.

Extending a ship in this manner is fairly routine as well, with many ships beyond cruise ships seeing the torch before being split. A newly built segment is then slid in place, the metal segments are welded together, wires, tubing and more are spliced together, before the in and outside are ready for a new coat of paint that makes it seem like nothing ever happened to the ship.

Continue reading “Cruise Ship-Lengthening Surgery: All The Cool Companies Are Doing It” →

Misleading GPS, Philosophy Of Maps, And You

September 10, 2024 by Bryan Cockfield 19 Comments

The oft-quoted saying “all models are wrong, but some are useful” is a tounge-in-cheek way of saying that at some level, tools we use to predict how the world behaves will differ from reality in some measurable way. This goes well beyond the statistics classroom it is most often quoted in, too, and is especially apparent to anyone who has used a GPS mapping device of any sort. While we might think that our technological age can save us from the approximations of maps and models, there are a number of limitations with this technology that appear in sometimes surprising ways. [Kyle] has an interesting writeup about how maps can be wrong yet still be incredibly useful especially in the modern GPS-enabled world. Continue reading “Misleading GPS, Philosophy Of Maps, And You” →

Why Have Seven Segments When You Can Have 21?

September 10, 2024 by Dave Rowntree 35 Comments

IO user [monte] was pointed towards an 1898 display patent issued to a [George Mason] and liked the look of the ‘creepy’ font it defined. The layout used no less than 21 discrete segments to display the complete roman alphabet and numerals, which is definitely not possible with the mere seven segments we are all familiar with. [monte] then did the decent thing and created a demonstration digit using modern parts.

For the implementation, [monte] created a simple PCB by hand (with an obvious mistake) and 3D-printed an enclosure and diffuser to match. After a little debugging, a better PCB was ordered from one of the usual overseas factories. There isn’t a schematic yet, but they mention using a CH32V003 Risc-V micro, which can be seen sitting on the rear of the PCB.

Maximum flexibility is ensured by storing every glyph as a 32-bit integer, with each LED corresponding to a single bit. It’s interesting to note the display incorporates serifs, which are definitely optional, although you could display sans-serif style glyphs if you wanted to. There is now a bit of a job to work out how to map character codes to glyph codes, but you can have a go at that yourself here. It’s still early doors on this project, but it has some real potential for a unique-looking display.

We love displays—every kind. Here’s a layout reminiscent of a VFD digit but done purely mechanically. And if you must limit yourself to seven digits, what about this unique thing?

Continue reading “Why Have Seven Segments When You Can Have 21?” →

Mobile Coffee Table Uses Legs To Get Around

September 10, 2024 by Bryan Cockfield 22 Comments

For getting around on most surfaces, it’s hard to beat the utility of the wheel. Versatile, inexpensive, and able to be made from a wide array of materials has led to this being a cornerstone technology for the past ten thousand years or so. But with that much history it can seem a little bit played out. To change up the locomotion game, you might want to consider using robotic legs instead. That’s what [Giliam] designed into this mobile coffee table which uses custom linkages to move its legs and get itself from place to place around the living room.

Continue reading “Mobile Coffee Table Uses Legs To Get Around” →