Building a rocket ship may sound romantic, but there are a lot of nitty-gritty details behind the work – and that’s what Amazon billionaire Jeff Bezos is celebrating in his latest email about Blue Origin’s BE-4 rocket engine.
Blue Origin, the space venture that Bezos founded back in 2000, is building the engine for use on United Launch Alliance’s next-generation Vulcan rocket as well as Blue Origin’s own New Glenn rocket. The plan is to start testing the engine early next year, and start flying the rockets by 2019.
There’s a bit of competitive pressure involved: United Launch Alliance has Aerojet Rocketdyne’s AR-1 engine waiting in the wings, just in case Blue Origin and the BE-4 don’t hit their marks.
The BE-4 engine will be fueled by liquid natural gas, unlike the hydrogen-fueled BE-3 engine that Blue Origin is using on the suborbital New Shepard rocket ship that it’s testing in West Texas. It’s designed to produce 550,000 pounds of thrust, as opposed to 110,000 pounds of thrust for the BE-3.
That means new technologies have to be employed to build the BE-4 – and today, Bezos called attention to one of those technologies: the automated electrical discharge machining drill, or EDM. Here’s how he describes the EDM in all its geeky glory:
“For BE-4, not only do we have to design the engine itself, we also have to develop custom tools to make it. One of these tools is an automated electrical discharge machining (EDM) drilling machine. The EDM precisely locates and burns more than 4,000 tightly dimensioned holes into the nozzle and main combustion chamber, providing entry to the regenerative cooling channels.
“As far as we know, this particular EDM machine is the only one of its kind in the world. It has 11 axes of motion allowing for precise hole location and accuracy within a few thousands of an inch. Its dual-head design results in reduced cycle time for the drilled holes. Brass multichannel electrodes are used to drill the holes. Water can be pumped through the electrode in order to speed up the drilling cycle. The use of water also helps flush the hole and remove the powder-like foreign object debris generated by the process. This eliminates the concern for plugging cooling channels, which can easily occur with conventional drilling methods. A pair of automated electrode-changing stations allows the EDM to continuously operate for long cycle times at an average rate of one hole every 90 seconds.
“Building and operating custom tools of this magnitude is a big investment, but it’s critical for developing an engine that will power America’s access to space in the future.
“A pretty wise investment, if you ask me.
“PS: Blue Origin is hiring. Check out our Careers page and apply.”
Drilling 4,000 holes at the rate of 90 seconds per hole adds up to, um, 100 hours’ worth of drilling. But imagine doing all that work by hand. That’s what engineers had to do more than a half-century ago when they built the Apollo F-1 rocket engines that sent NASA’s spaceships to the moon.
Strangely enough, Bezos has a reason to be familiar with the difference. Three years ago, he funded an expedition to recover F-1 engine components from the bottom of the Atlantic Ocean, and some of those parts show the intricate (albeit corroded) patterns of hand-drilled holes. For comparison’s sake, check out this example, which is now on display at Seattle’s Museum of Flight: