A Farewell To Hackaday’s Favorite Falcon 9 Booster

With the notable exception of the Space Shuttle, rockets and spacecraft have always been considered disposable. It’s a slow and expensive way to travel, akin to building a new airliner for every flight, but it was the easiest option. These vehicles have always represented the pinnacle of engineering and material science of their time, and just surviving the trip to space once was an incredible accomplishment. To have another go around would have been asking too much of the technology. Even looking back on the Space Shuttle program, there’s plenty of debate about whether or not the reusable design really paid off in the end.

So SpaceX’s ability to land, refurbish, and refly the first stage of their Falcon 9 booster is no small accomplishment. After demonstrating the idea was possible in 2017, the company made numerous changes to the latest iteration of the rocket with reusability in mind. Known as Block 5, this version of the Falcon 9 is designed to be more survivable and require minimal servicing between flights. The company says its cheaper and faster to reuse the Block 5 than it would be to build a new one for each flight, allowing the company to approach spaceflight more like commercial aviation.

Falcon 9 launch and landing streaks
Falcon 9 launch and landing streaks. (Source: SpaceX)

With a fleet of Block 5 boosters now in rotation, SpaceX has given them serial numbers not unlike an airplane’s tail number. It might not be the kind of thing the general public would normally be aware of, but these serial numbers have allowed a dedicated community of space aficionados to keep track of the missions each booster has flown.

Unfortunately the story of one of these rockets, officially referred to as “Cores” in SpaceX parlance, was recently cut short. Core B1056, returning from the Starlink 4 mission on February 17th, failed to land on the autonomous spaceport drone ship (ASDS) Of Course I Still Love You and splashed down in the ocean. It’s still unclear what condition the booster was in after its soft landing in the water, but when the recovery ships returned to port empty handed, there was no question as to the fate of B1056.

From a purely business standpoint, the failure of any of SpaceX’s boosters means lost time and revenue. But in some ways B1056 had established itself as the vanguard of the fleet, managing to either set or break a number of records in its relatively short life. The destruction of the most thoroughly flight proven Block 5 booster is a stark reminder that there’s very little about spaceflight that could be called routine.

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Riding Shotgun In The Apollo 12 Lunar Lander

Last week we had a walk through of the Lunar Module’s source code with Don Eyles, who wrote the landing programs. Now you can take a rather thrilling ride to see Don’s code in action.

Below is an annotated video of the Apollo 12 landing, in real-time. It’s worth setting aside a quarter-hour to check it out. In an age where everyone is carrying around an HD (or way better) camera in their pocket, following along with radio broadcasts, still images, and small slivers of video might not sound that awesome. But it is!

p63-apollo-12-codeThe video takes us from Powered Descent Initiation through touchdown on the Moon with Pete Conrad and Alan Bean. As the audio plays out the video has annotations which explain what is going on and that translate the jargon used by the team. With the recently celebrated push to publish the source code you can even follow along as the video displays which program is running at that time. Just search for the program code and you’ll find it, like this screenshot of the P63 routine. The code comments are more than enough to get the gist of it all.

If you enjoy this, the description of the YouTube video below includes links to similar videos for Apollo 11, 14, 15, 16, and 17.

[Thanks to Paul Becker for sending along this video]

Aircraft Carrier Is Moving Target For Autonomous Quadcopter

[Karl-Engelbert Wenzel] developed a UAV capable of taking off and landing on a moving platform autonomously. The platform operates aircraft-carrier-style by driving around the room in circles. The quadcopter tracks a grid of IR LEDs at the front of the landing deck by using the IR camera from a Wii remote. The best part is that the flight controls and processing are all done by the copter’s onboard ATmega644 processor, not requiring a connection to a PC. The landings are quite accurate, achieving a maximum error of less than 40 centimeters. In the video after the break you can see the first landing is slightly off the mark but the next two are dead on target.

So build yourself a mobile platform and pair it up with your newly finished quadcopter to replicate this delightful hack.

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