America's space news has been pretty good of late, with SpaceX recently completing its fourth official "Crew" mission to the International Space Station (ISS) and Boeing succeeding with an uncrewed test flight of its Starliner spacecraft to the same destination.

But not all the news is good.

While SpaceX is clearly leading the space race right now, and Boeing is at least back in the race, one other major space company has hit a hiccup. Northrop Grumman (NOC 0.29%), along with SpaceX, is responsible for keeping ISS supplied with consumables -- and it is running short of rockets.

From Russia, with rockets

More precisely, Northrop Grumman is running short of both RD-181 rocket engines, which it buys from NPO Energomash in Russia, and Antares first-stage rockets (which incorporate two RD-181 engines per stage) that it buys from Yuzhmash in Ukraine.

Antares is the rocket Northrop uses to launch supplies to ISS under its commercial resupply (CRS) contract with NASA, and Antares uses up to three rocket stages to get to ISS. Northrop builds the rocket's second and third stages itself but has outsourced production of the first stage -- the big one -- to Ukraine and to Russia.

Now, Northrop was able to acquire enough engines and stages prior to war breaking out to cover its next two scheduled resupply missions to ISS -- one scheduled for August 2022 and a second for early 2023, reports SpaceFlightNow.com. Problem is, NASA awarded Northrop six more CRS missions in March. This is a problem because -- as you may have heard -- Russia and Ukraine are currently engaged in a shooting war. Russia has been sanctioned by the U.S. for its aggression, making further purchases of RD-181 engines problematic. And Ukraine is being bombed continually, which makes the production of new Antares first-stages difficult.

So, Northrop Grumman needs a Plan B if it's to fulfill its contractual obligations to launch those CRS missions.

Plan B for inner space

Speaking on Northrop Grumman's first-quarter 2022 post-earnings conference call on April 28, Northrop CEO Kathy Warden assured investors that "we have a plan in place that we could use other sources" to acquire the engines and/or stages needed for the six additional CRS missions. But she was not more specific on this point.

In the past, when Northrop has run into problems with its own rockets, it has turned to rival United Launch Alliance (ULA) -- a joint venture between Boeing and Lockheed Martin -- for help getting its Cygnus resupply capsules to ISS atop ULA's Atlas V rockets. Although ULA is phasing out Atlas V, it's possible that ULA's replacement rocket, dubbed Vulcan Centaur, could plug this gap and enable Northrop to continue fulfilling its contract, albeit probably at lower profit margins for Northrop.

Alternatively, Northrop might turn to SpaceX and its Falcon 9 rocket for a lift. SpaceX, however, is an even closer competitor to Northrop than ULA, inasmuch as SpaceX is one of two companies not named Northrop (the other being Sierra Nevada Corp) that have also received CRS contracts from NASA. Partnering with SpaceX to send its Cygnus capsules to ISS, therefore, wouldn't just result in a hit to profit margins but could also prompt NASA to ask the question of why it needs to give any more contracts to Northrop if SpaceX will end up doing the bulk of the work!

A longer-term solution

So, in a nutshell, the situation is this: Northrop has a contract to resupply ISS -- but cannot fulfill this contract on its own. Temporary solutions exist, but they're all suboptimal, and what Northrop really needs is a long-term solution: An American rocket engine that it can use to send its spacecraft to orbit.

I see a couple such long-term solutions. First and most ideal, Northrop could develop its own rocket engine -- although that would take time. Second and more immediate, American engine-maker Aerojet Rocketdyne (AJRD) has an AR1 rocket engine ready for use. Aerojet originally designed the AR1 to power ULA's Vulcan Centaur, but ULA decided to buy a rival engine from Blue Origin instead. This sets up a situation in which Northrop has a contract but needs an engine, while Aerojet has an engine and needs a contract (with someone to buy the engine).

1 + 1 = 2. The math on this problem seems obvious. I wouldn't be a bit surprised if in the not-too-distance future we hear that Northrop and Aerojet have struck a deal that will solve each company's problem -- and ensured America has three solutions for keeping ISS supplied in the process.