Orbital Sciences picks another Russian engine for Antares

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The heat of competition: In its effort to replace the old Cold War Soviet-era refurbished Russian engines for the first stage of its Antares rocket, Orbital Sciences today announced that it will instead buy a different modern-built Russian engine.

Designated the RD-181, the new engine will be used on Antares in shipsets of two to accommodate as closely as possible the two-engine configuration built around the AJ-26 engines supplied by Aerojet Rocketdyne, Orbital Sciences managers said Dec. 16. A descendant of the RD-171 that powers the Ukrainian-built Zenit launch vehicle, the RD-181 will be manufactured in the same Khimki factory that builds the RD-180 used on the United Launch Alliance Atlas V. It closely resembles the RD-191 on Russia’s new Angara launcher and the RD-151 that powers South Korea’s Naro-1 launch vehicle.

It appears that this is the only engine presently available that can do the job. In the long run however it puts Antares and Orbital Sciences at a competitive disadvantage. Even though the sanctions against using Russian engines, passed by Congress, only apply to military launches, Orbital’s continuing reliance on Russian engines will limit their customer base.



  • geoffc

    RD-170 is a really nice engine. F-1 class performance (1.6 Mlbs thrust) with four thrust chambers. Cut it in half, only two thrust chambers and 800 KLbs thrust RD-180. Cut it in half again and you get a 400 Klb thrust RD-193/181/151.

    A successful family of engines (Though only Atlas 3/5 has ever used the RD-180).

  • Jake

    Is the RD-170 a quality engine? It seems that much of what Russia produces is plagued with quality problems. I seem to remember that they still don’t have their power supply working on the ISS and rely on the USA for power to their part of the station? Does the RD-170 work as advertised?

  • “It appears that this is the only engine presently available that can do the job. In the long run however it puts Antares and Orbital Sciences at a competitive disadvantage.”

    How does this put Orbital at a competitive disadvantage, and how will it limit their customer base? The bill Congress passed hasn’t been signed into law, and since the contract for the engines (20 firm engines and option for 40) has already been signed, it will not be affected by the provision in the 2015 Defense Appropriation bill, which means that national security/defense launches can be made on Antares rockets as well as government and private. So, again, how does the use of this engine limit Orbital’s customer base and put it a competitive disadvantage?

  • If I have read the continuing resolution properly, it forbids the use of Russian engines on future military missions, and it only grandfathers the engines that ULA bought for Atlas 5. Moreover, it has been signed into law. Based on this understanding, Antares will not be available for future military launches.

  • Andy Hill

    Won’t using a different engine require Atlas V to be recertified as it will basically be a new rocket, I see another SpaceX lawsuit looming if it is not?

    If ULA has 20 engines on order and a possible extra 40 this should mean there is plenty of time to develop a new US replacement. The US has outsourced its rocket industry to such a point that it getting untenable, this is a ludicrous situation that needs to be changed. For pity’s sake start manufacturing your own engines and kick the Russians into touch- its not all about money what happened to national pride?

  • wodun

    I think ULA is still banned by congress from using the Russian engines but that Obrital Sciences is allowed to use them. Difference being one is for the military and the other for NASA.

    Regardless though, this is exactly right for both companies, “The US has outsourced its rocket industry to such a point that it getting untenable, this is a ludicrous situation that needs to be changed.”

  • If you want to get technical about it, the prohibition per the wording of the bill only applies to the EELV program, which is the domain of ULA. The prohibition does not extend to Orbital. Therefore, it is plausible that Orbital could compete for defense launches even with Russian rocket engines.

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