Small Space News Story Roundup 75

Just a couple of stories that standout above the noise to me 

Remember Rocketdyne?  

It's sort of a trick question, but with a point. Rocketdyne was one of the big names in the Space 1.0 days. They were founded in 1955 - over 70 years ago. They aren't quite gone now, but I wouldn't be surprised to see them gone by 2030. 

A half-century ago, Rocketdyne manufactured almost all of the large liquid-fueled rocket engines in the United States. The Saturn V rocket that boosted astronauts toward the Moon relied on powerful engines developed by Rocketdyne, as did the Space Shuttle, the Atlas, Thor, and Delta rockets, and the US military’s earliest ballistic missiles.

Rocketdyne’s dominance began to erode after the end of the Cold War. The company started in 1955 as a division of North American Aviation, then became part of Rockwell International until Boeing acquired Rockwell’s aerospace division in 1996. Rocketdyne continually designed and tested large new rocket engines from the 1950s through the 1980s. Since then, Rocketdyne has developed and qualified just one large engine design from scratch—the RS-68—and it retired from service in 2024. 

The company was first sold by ULA in 2005 for $700 million (about $1.2 billion today). This was about six years before the end of the Space Shuttle program and around the startup of SpaceX - launching their first experimental launches. 

There are at least nine medium to large liquid-fueled rocket engines in production or in advanced development in the United States today, and just one of them is from the enterprise once known as Rocketdyne: the RS-25 engine used to power the core stage of NASA’s Space Launch System (SLS) rocket.

The RS-25 is often referred to as the SSME - Space Shuttle Main Engine - and all of the engines set to fly on the Space Launch System are not just the same model, they are all "used" engines that have previously flown on Shuttle missions. 

It's interesting that United Launch Alliance, Rocketdyne's big customer after the end of the shuttle program, abandoned them in favor of Blue Origin's engines for their Vulcan rocket. 

The parent company of Aerojet purchased Rocketdyne in 2013 to form Aerojet Rocketdyne. L3Harris closed its acquisition of Aerojet Rocketdyne in 2023, creating a space propulsion and power systems business unit and retiring the historic Rocketdyne name. Now, just two-and-a-half years later, L3Harris announced Monday it is selling a 60 percent stake in its newly created propulsion and power business to AE Industrial Partners, a Florida-based private equity firm. L3Harris will retain 40 percent ownership. 

The RS-25 is not part of this sale. Apparently, Rocketdyne is holding onto a dream of an SLS add-on contract to build the RS-25s as "Cost Plus." 

There is another big portion of the Rocketdyne market that hasn't been mentioned, the RL10 upper stage engine used on ULA's Vulcan. AE Industrial Partners has talked up the idea of modernizing the engine in the West Palm Beach (Florida) plant that builds them. It sounds like they need to modernize the way the engines are built.

RL10s have flown on rockets since the 1960s and historically required significant touch labor and manual fabrication, driving up their cost. 

3I/ATLAS isn't an alien spacecraft, astronomers confirm

Space.com entitles their story, "Interstellar comet 3I/ATLAS isn't an alien spacecraft, astronomers confirm. 'In the end, there were no surprises.' "

The amount of silly stuff floating around about this comet surprised me - and not just the amount, but some of the sources surprised me, too. While it would have been far more interesting to me to be evidence of an advanced civilization sending out probes than to just be another rock passing in the night, there were just too many issues with the evidence for that. 

Astronomers used the Green Bank Telescope, employed in the Breakthrough Listen extraterrestrial signal-hunting astronomy project, to search 3I/ATLAS for measurable signs of technology from extraterrestrial civilizations, or "technosignatures." 

"We all would have been thrilled to find technosignatures coming from 3I/ATLAS, but they're just not there," lead researcher Benjamin Jacobson-Bell from the University of California, Berkeley, told Space.com. "Finding no signals was the result we expected, due to the significant evidence for 3I/ATLAS being a comet with only natural features.

"The evidence was against 3I/ATLAS being one such probe, but we would have been remiss not to check."

Here on the blog, we've had little discussion about this, but I'll borrow something I wrote in a comment back around the start of the controversy:

Why do I think it's basically just another rock? Because it's acting like a rock. It's on a purely ballistic trajectory. It's moving fast compared to things we're used to observing - which is, after all, the last few years of human history - but it's not moving fast compared to the speeds required for living beings to cover the distances it has come. Good old Wikipedia says it's moving at 58km/sec or 0.000193c. We don't know where it came from, but even if it came from the closest stars at 4 light years away, that means more than 20,000 years to get here. Who's going to launch a system that slow, and why? What kind of system could work over 20,000 years without failing? If they wanted to take over our solar system or take our planet, if they have lifespans similar to ours, 20,000 years makes coming here to take over pretty much impossible. 

Comet 3I/ATLAS streaks across a dense star field in this image captured by the Gemini Multi-Object Spectrograph (GMOS) on Gemini South at Cerro Pachón in Chile. The multicolored streaks are stars in the background of the image.

(Image credit: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the ScientistImage Processing: J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab))

3i/Atlas was fun, and moderately interesting. I never looked at it myself, but that's true of almost all of the barely visible comets that come through the solar system in any given year.