ISS, Antares and the Russian war of aggression

If you’ve not heard of the Antares rocket and the role it plays launching supplies to the ISS from the U.S., that’s okay. Antares has quietly carried out its mission, mostly without incident, for the past four years. Each launch from NASA’s Wallops Island Spaceport in Virginia lofts a Cygnus cargo module built by Orbital ATK to the ISS. SpaceX gets lots more coverage of its ISS launches thanks to its expert marketing team. Northrop Grumman is the manufacturer/purveyor of the Antares.

Antares from its inception was built on Russian (and USSR) rocket motors. Today, the first-stage propulsive force that helps get the Antares Cygnus to orbit comes from two Russian RD-181 motors. The Antares first stage core is manufactured by Yuzhmash, a Ukrainian company.

Thanks to Russia’s war of aggression against Ukraine, Northrup Grumman can no longer source new RD-181 engines. Ukraine is too badly battered and disrupted to reliably produce the first stage cores used by Antarers. At this point, Antares has supplies sufficient for two more launches.

From its beginnings, the Russian attack on the Ukraine — and the USA’s response — were expected to have downstream effects on International Space Station operations. Initial concerns focused on whether or not Russia would continue to sell seats on its Soyuz taxi to carry US astronauts to and from the orbital space station. Some wondered if Russia would decouple from the ISS program.

So far, the operational flow on ISS has not been substantially impacted. Thankfully, SpaceX Crew Dragon and the version of Dragon used for resupply of ISS were up and running before the European conflict got underway. With Boeing apparently closing in on operational status for its CST-100 crew transport, greater redundancy for getting astronauts to ISS is about to arrive.

The possible loss of Antares would affect the cadence of ISS resupply missions and potentially require a rescheduling of on-orbit operations while alternative paths to orbit are worked out. The Cygnus can reach orbit using the Atlas V manufactured by ULA. The Atlas V uses the RD-180 engine also manufactured in Russia. In any case, ULA is already scheduled to fly-out its existing inventory of Atlas, so a ride might not be available on the Atlas V.

With the Vulcan rocket — the follow-on to Atlas — not ready to fly, we may soon see a push to use the Falcon 9 to deliver Cygnus to ISS. A solution will be needed soon.

One thing is for certain: the wisdom of commercial resupply and commercial crew programs is being validated by today’s geopolitical complexities. In retrospect — always easy to say things retrospectively — an emphasis or requirement that rocket motors be sourced within the US seems essential.

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