Let’s be fair about Russian engines

29 12 2014

The Motley Fool just posted an article about Orbital Sciences electing to replace the Soviet-designed and Soviet-built NK-33 engine on its Antares rocket with the Russian-built RD-181, an offshoot of the RD-180 engine currently in use on the Atlas V. The article then went on to speculate about this decision ultimately being a win for SpaceX, an American company that designs and builds its own engines for for its own rockets. I scrolled down to the comments section, which was my mistake, to see lots of people who clearly know nothing of rockets or aerospace engineering, but know they don’t like Russia, pissing on the RD-181.

In any engineering field, knee-jerk reactions are less tolerable than in other, less rigorous fields. When selecting an engine for a rocket, you have to look facts and statistics squarely in the eye and calmly make a logical, justifiable choice. The NK-33, RD-180, and RD-181 are all proven, powerful engines that meet the requirements for their rockets. The only American engine to outperform all Russian/Soviet engines in terms of thrust-to-weight ratio is the Merlin 1D, currently in service on the Falcon 9.

Whether Orbital thought they could get a better price on the RD-181 or SpaceX was not interested in selling its engines, I have no idea. The NK-33 is the second-most powerful LOx/kerosene engine in terms of TWR and the RD-181 is the third.

When the modified NK-33s (later renamed AJ-26) were installed on the Antares rocket, both engines had been taken apart, rebuilt, test, fired, and tested again. These were not some chunks of rust that Orbital got for a deal on the Russian black market. These were well engineered, tested, and vetted engines. Unfortunately, you cannot remove every bit of risk from a launch.

I don’t like what Russia has been doing to its neighbors, Ukraine in particular. I don’t like that they make so much money off oil and gas any more than we use lots of oil and gas. I think there were managerial oversights during the Shuttle-Mir program. I, like most Americans, have reasons to not completely trust Russia. However, feelings mean nothing when you are staring at specs and data and trying to make an engineering decision.

If you are an American and you want us to have better, more powerful, more efficient, and more reliable engines than the Russians, go out and build them. Otherwise, shut up about it and accept that Orbital made the best decisions they could and that’s all we can expect of anyone.





ULA’s future

13 08 2014

Earlier today, United Launch Alliance CEO and President Michael Gass abruptly retired immediately following what was surely a tense board meeting. Mr. Gass was presumably let go after sanctions by Russia left the future of ULA’s workhorse, the Atlas V, in question.

Atlas V (401) launches with LRO and LCROSS

Atlas V 401 launch

The ULA is a joint venture between Boeing and Lockheed to provide launch services. Their main customer is the US Federal government and the bulk of their flights are for the US Air Force and the National Reconnaissance Office. NASA’s Mars rovers were also launched by ULA rockets. ULA was formed to consolidate operations and control costs for government space missions. Unfortunately, this has resulted in an effective monopoly and costs for government-related launches have gone through the roof.

ULA relies on two main launchers, Delta IV and Atlas V. Both of these are expandable and flexible to accommodate different launch requirements. The first stage of the Atlas V relies on the RD-180 engine, which is imported from Russia and is a result of the Soviet Union’s efforts to build a Moon rocket in the 1960s. It is a direct descendant of the NK-33, which was featured on the N1.

Though ULA bought the designs and the rights to build an American version of the RD-180, they have not because it would cost billions of dollars and at least three years. It was simply easier and cheaper in the short term to buy the engines from Russia. With tensions between the United States and Russia over Russia’s attempted annexation of the Crimean Peninsula, the Russian government has made it as difficult as possible for ULA to buy these engines. Without any more engines coming in, ULA has enough for another three years of Atlas V flights.

Besides putting several American national security launches at the mercy of the Russian government, this is also likely to interfere with ULA’s participation NASA’s Commercial Crew program. Of the three candidate spacecraft, two of them, Boeing’s CST-100 and Sierra Nevada Corporation’s Dream Chaser, are expecting to use the Atlas V at around the same time the RD-180 stockpile dries up. (The third ship is SpaceX’s Dragon, which already makes use of the company’s Falcon 9 rocket.)


Delta IV Common Booster Cores

Delta IV Common Booster Cores being prepared for a Delta IV Heavy launch

With growing competition from new aerospace companies, SpaceX in particular, and a fleet of aging hardware, ULA needs to move fast to survive. They need cheaper, more capable launch vehicles with all major components (including engines) produced domestically. In the short term, plans should be made to sunset Atlas V after the existing stockpile of RD-180s is exhausted, but retain the Delta II and Delta IV series until a new vehicle can be put into service.

Russia's new Angara launch system

Four different configurations of Russia’s new Angara launch system

Delta IV’s use of Common Booster Cores (CBCs) is a clever idea and it should be retained. Russia’s upcoming Angara rocket family will eventually supplant Dnepr, Rokot, Proton, and Soyuz for most launch situations and will make use of its own version of the CBC. By manufacturing large quantities of smaller, identical stages and combining them as necessary, there is potential to drive costs down.

Both ULA systems use liquid oxygen as an oxidizer. The current Atlas V uses RP-1 and Delta IV uses liquid hydrogen. Other rockets, like Proton use hypergolic fuels, which are highly corrosive. There are advantages and disadvantages to every fuel combination and the best one to used would depend on the primary application of the rocket, as well as forthcoming technologies. The ideal fuel would depend on what sort of work ULA is doing in five years. If it’s small payloads, a solid-fuel rocket like the Minotaur would be appropriate. For the moment, Atlas V’s RP-1 first stage and LH2 Centaur upper stage are a very effective combination and would be ideal for medium-lift situations.


ULA went a long time without any meaningful competition and it will take some time for it to become competitive again. I am a big SpaceX fan and I hope that they will be allowed to fairly compete for Air Force contracts alongside ULA. That said, I wish ULA success and to compete with SpaceX so they can force each other to be better.


 

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