Crew Dragon’s Short Hop Begins The Era Of Valet Parking At The ISS

April 15, 2021 by Tom Nardi 19 Comments

They weren’t scheduled to return to Earth until April 28th at the earliest, so why did NASA astronauts Michael Hopkins, Victor Glover, and Shannon Walker, along with Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, suit up and climb aboard the Crew Dragon Resilience on April 5th? Because a previously untested maneuver meant that after they closed the hatch between their spacecraft and the International Space Station, there was a chance they weren’t going to be coming back.

On paper, moving a capsule between docking ports seems simple enough. All Resilience had to do was undock from the International Docking Adapter 2 (IDA-2) located on the front of the Harmony module, itself attached to the Pressurized Mating Adapter 2 (PMA-2) that was once the orbital parking spot for the Space Shuttle, and move over to the PMA-3/IDA-3 on top of Harmony. It was a short trip through open space, and when the crew exited their craft and reentered the Station at the end of it, they’d only be a few meters from where they started out approximately 45 minutes prior.

The maneuver was designed to be performed autonomously, so technically the crew didn’t need to be on Resilience when it switched docking ports. But allowing the astronauts to stay aboard the station while their only ride home undocked and flew away without them was a risk NASA wasn’t willing to take.

What if the vehicle had some issue that prevented it from returning to the ISS? A relocation of this type had never been attempted by an American spacecraft before, much less a commercial one like the Crew Dragon. So while the chances of such a mishap were slim, the crew still treated this short flight as if it could be their last day in space. Should the need arise, all of the necessary checks and preparations had been made so that the vehicle could safely bring its occupants back to Earth.

Thankfully, that wasn’t necessary. The autonomous relocation of Crew Dragon Resilience went off without a hitch, and SpaceX got to add yet another “first” to their ever growing list of accomplishments in space. But this first relocation of an American spacecraft at the ISS certainly won’t be the last, as the comings and goings of commercial spacecraft will only get more complex in the future.

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3D Printing A Long Range Nerf Blaster

April 15, 2021 by Lewin Day 11 Comments

The modified Nerf scene used to be about getting the absolute maximum performance out of Hasbro’s off-the-shelf foam dart blasters. The community quickly found the limits of plastic parts made down to a price, and an underground market for heavier springs and CNC-machined upgrades sprung up. Eventually, however, the advent of 3D printing and cheaper home machine tools led to a rise in popularity of bespoke blasters. [Zach] has long advocated for their supremacy, and has made a long-range blaster aimed at newcomers to the hobby. (Video, embedded below.)

The blaster is built around the popular Caliburn spring-powered design, originally created by [Captain Slug]. Modifications by [Zach] involve a longer barrel, relocated side-feeding magazine port, and other modifications designed to suit the long-range sniping role. There’s even a special “rifled” stabiliser on the end designed to reduce the effects of muzzle blast from disturbing the dart as it leaves the barrel.

It’s a design that very much builds on the efforts of the wider Nerf community, and is all the better for it. [Zach] has shared files and links to parts bundles to help get enterprising builders up and running with a minimum of fuss. We’d love to take the long blaster out for a round or three ourselves – it may just be time to fire up the 3D printer!

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WiFive55: More Than A Smart 555 Replacement

April 15, 2021 by Stephen Ogier 40 Comments

“You could’ve done that with a 555 timer.” But what if all you have on hand is an ESP8266? [TechColab] needed to control a solenoid valve with a short pulse via a solid-state relay (SSR) but found that the trusty 555 timer was tricky to set properly. Additionally, they wanted to add features, such as fixed pulse length, that were difficult to implement—even with multiple timers. Still wanting to keep things cheap and accessible, [TechColab] has created the WiFive55, a 555 replacement based on the ESP-01 ESP8266 board.

[TechColab] began by investigating existing ESP-01 solid-state relay boards but found that many of them momentarily enable the output on startup—a risk [TechColab] deemed unacceptable. This was resolved in the WiFive55 by adding an RC filter to the SSR output, eliminating the output glitches at the cost of slowing switching time to around 20 ms—an acceptable trade for many SSR applications.

Since they were going to design a new PCB to support this improved ESP-01 SSR controller, [TechColab] decided to go all-out. To support loads of widely varying sizes, the PCB supports an optoisolator that switches up to 1 A, a MOSFET that switches up to 2 A, and an on-board relay or SSR that can switch up to 3 A. For heavy loads, it includes connections for an off-board SSR, which allow it to switch whatever current the SSR can handle (easily over 50 A). Because the ESP-01 is slightly more capable than the 555, the WiFive55 supports control via WiFi, GPIO, serial, and push-button. Keeping with the WiFive55’s original role as a 555 replacement, it even includes a header exposing a 555-like trigger and output interface!

We always like seeing inexpensive boards like the ESP-01 being used to their full potential, and we can’t wait to see what software [TechColab] cooks up for this! If you’re interested in getting started with the ESP-01, you might consider starting with this guide to blinking an LED over WiFi.