On April 2nd, 2018 a Falcon 9 rocketed skywards towards the International Space Station. The launch itself went off without a hitch, and the Dragon spacecraft delivered its payload of supplies and spare parts. But alongside the usual deliveries, CRS-14 brought a particularly interesting experiment to the International Space Station.
Developed by the University of Surrey, RemoveDEBRIS is a demonstration mission that aims to test a number of techniques for tackling the increasingly serious problem of “space junk”. Earth orbit is filled with old spacecraft and bits of various man-made hardware that have turned some areas of space into a literal minefield. While there have been plenty of ideas floated as to how to handle this growing issue, RemoveDEBRIS will be testing some of these methods under real-world conditions.
The RemoveDEBRIS spacecraft will do this by launching two CubeSats as test targets, which it will then (hopefully) eliminate in a practical demonstration of what’s known as Active Debris Removal (ADR) technology. If successful, these techniques could eventually become standard operating procedure on future missions.
Continue reading “Space Garbage Truck Takes Out The Trash” →
Why do people drop hundreds of dollars on designer goods? The easy answer is that, in theory, the goods are worth the expense. The materials, craftsmanship, and attention to detail are all top-notch and culminate in the finest finery money can buy.
So, would you spend hundreds of dollars on a designer wallet? If you have leather crafting skills and a thrift store nearby, you could just follow [Corter Leather]’s example and make your own. He found a diamond in the rough—a genuine, well-loved Louis Vuitton bag languishing in a secondhand shop. The leather bottom and handles were dry and worn, but the signature LV canvas was still in great shape. Never crafted leather? If you can’t get free scraps for practicing, then deconstructing cheap, used stuff is the next best thing.
To isolate the canvas, [Corter] carefully removed the bag’s handles, bottom, liner, and zipper and then popped the rivets and peeled the backing from the fabric. He drew up a pattern in Illustrator that pays homage to the illustrious designer’s wallets and cut the pieces out of 3oz vegetable tanned leather using card stock templates.
[Corter] brought his A-game to the details. Every visible edge is painted Italian red, which he applied with an awl for a crisp line. The larger pockets have hidden stitches that keep cards from drifting to the bottom and throwing off the shape. No need to open your wallet to see how he did it—just watch the video after the break.
Though it technically isn’t a real Louis Vuitton, a thief wouldn’t know it until later. Maybe [Corter] should add a pickpocket alarm.
Continue reading “DIY Designer Wallet From Designer Bag” →
There are a multiplicity of transmission modes both new and old at the disposal of a radio amateur, but the leader of the pack is still single-sideband or SSB. An SSB transmitter emits the barest minimum of RF spectrum required to reconstitute an audio signal, only half of the mixer product between the audio and the RF carrier, and with the carrier removed. This makes SSB the most efficient of the analog voice modes, but at the expense of a complex piece of circuitry to generate it by analog means. Nevertheless, radio amateurs have produced some elegant designs for SSB transmitters, and this one for the 80m band from [VK3AJG] is a rather nice example even if it isn’t up-to-the-minute. What makes it rather special is that it relies on only one type of device, every one of its transistors is a BC547.
In design terms, it follows the lead set by other simple amateur transmitters, in that it has a 6 MHz crystal filter with a mixer at either end of it that switch roles on transmit or receive. It doesn’t use the bidirectional amplifiers popularised by VU2ESE’s Bitx design, instead, it selects transmit or receive using a set of diode switches. The power amplifier stretches the single-device ethos to the limit, by having multiple BC547s in parallel to deliver about half a watt.
While this transmitter specifies BC547s, it’s fair to say that many other devices could be substituted for this rather aged one. Radio amateurs have a tendency to stick with what they know and cling to obsolete devices, but within the appropriate specs a given bipolar transistor is very similar to any other bipolar transistor. Whatever device you use though, this design is simple enough that you don’t need to be a genius to build one.
Via [G4USP]. Thanks [2ftg] for the tip.