Ozan Bellik's Blog

As I tried to show in Part 2: Performance , Vulcan would get a big performance boost from switching to Raptor. But is it worth it for ULA? And would SpaceX sell? Is it worth it for ULA? Performance is attractive, but at what cost? Since BE-4 seems to be adequate for ULA, and since an engine swap wouldn't get Vulcan flying any sooner this close to the finish line, what would ULA get out of switching? Contracts would have to be renegotiated, Vulcan structures (plumbing, thrust structure, lower dome position), would have to be modified, there would be software changes, and there might even be operational changes. The work would be non-trivial, and so would the one-time cost. What, besides raw performance, might make it worth it? Lower recurring costs, for one. Rumors circulated a while back of Raptor production costs falling below $2M, and this seems to be in line with numerous tweets from Elon Musk. And much more aggressive cost cutting is planned for the future. This, of course, is

In Part 1 , I introduced the idea of Raptor engines on Vulcan and why this has been proposed by space launch fans, and I ended with three questions: Would Raptors work on Vulcan? Would ULA buy them? Would SpaceX sell them? In this post, I will try to answer the first question, leaving the other two mostly for Part 3. I will briefly touch on the second question, though. ULA's CEO Tory Bruno has already politely said no to Elon Musk's joking offer and has also publicly stated that the BE-4 is the right engine for them. And indeed, replacing BE-4 even with a similar methalox engine would be no small feat. Mount points and plumbing, control software and timings, validation and integration procedures would all need to change. The oxidizer to fuel ratio would change and thus the oxygen/methane tank partition would no longer be optimal. Tanking operations might be impacted. And then there's of course all the negotiation and paperwork that would go into ensuring ULA was getting a g

ULA's Vulcan       Graphic Credit: RUAG As is common in aerospace, the debut of Vulcan, ULA's new launch vehicle, originally planned to take place in 2019 , has been delayed by about three years. Among the reasons for the delay, two stand out: 1. The payloads destined for the first two flights -- Astrobotic's Peregrine lunar lander, and SNC's Dream Chaser cargo spaceplane, aren't ready.        Peregrine                                  Dream Chaser      Credit: News 13 2. Blue Origin, the supplier of the BE-4 engines that will power Vulcan's first stage, has struggled to get their engines ready on schedule. As of January 2022, ULA is still waiting for flight-ready engines to integrate into Vulcan. BE-4    Credit: ULA This and other disappointments from Blue Origin have led many spaceflight fans to second guess ULA's decision to go with Blue Origin as their engine supplier and to wonder if another option might be open to ULA even now. Two engines tend to come