United Launch Alliance has started assembling its next Vulcan rocket\u2014the first destined to launch a US military payload\u2014as the Space Force prepares to certify it to loft the Pentagon\u2019s most precious national security satellites.<\/p>\n
Space Force officials expect to approve ULA\u2019s Vulcan rocket for military missions without requiring another test flight, despite an unusual problem on the rocket\u2019s second demonstration flight earlier this month.<\/p>\n
ULA has launched two Vulcan test flights. Military officials watched closely, gathering data to formally certify the rocket is reliable enough to launch national security missions. The first test flight in January, designated Cert-1, was nearly flawless. The Cert-2 launch October 4 overcame an anomaly on one of Vulcan\u2019s strap-on solid rocket boosters, which lost its exhaust nozzle but kept firing with degraded thrust.<\/p>\n
The rocket\u2019s twin BE-4 main engines, made by Blue Origin, corrected for the asymmetric thrust from the two strap-on boosters. Vulcan\u2019s Centaur V upper stage also fired its engines longer than planned to make up for the shortfall in performance from the damaged strap-on solid motor. Ultimately, the rocket reached its planned trajectory and delivered a dummy payload into interplanetary space.<\/p>\n
Col. James Horne, who oversees launch execution for Space Systems Command, called the test flight a \u201csuccessful launch\u201d in an interview with Ars. The nozzle failure caused a \u201csignificant loss of thrust\u201d from the damaged booster, he said.<\/p>\n
The Vulcan rocket\u2019s ability to overcome the dramatic nozzle failure, which was easily visible in video of the launch, \u201creally demonstrated the robustness of the total Vulcan system,\u201d Horne said.<\/p>\n
\u201cThey nailed the orbit, probably one of the most accurate orbital insertions that I\u2019ve seen them fly yet,\u201d he said. \u201cAnd at the end of the mission, they did some extended duration testing \u2026 which was not part of the orbital insertion. And even after that extended mission, they still had substantial performance reserve left over.\u201d<\/p>\n
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Horne said the Space Force is still analyzing data from the October 4 launch, but so far, officials expect to approve certification for the Vulcan rocket. An agreement between the Space Force and ULA requires two successful flights of the Vulcan rocket before the military will entrust it with a national security mission.<\/p>\n
\u201cFor the purposes of the certification plan, which requires that the certification flight deliver the satellite or payload\u2014in this case, the mass simulator\u2014to its specified orbit successfully\u2026 that\u2019s what happened,\u201d Horne said. \u201cSo this was a successful completion of that mission.\u201d<\/p>\n
He added that early assessments by the Space Force show that, had the same booster anomaly happened on either of the first two military missions slated to fly on Vulcan, the rocket could have still achieved an on-target orbit, with performance margin.<\/p>\n
\u201cSo it was a successful Cert flight, and now we\u2019re knee-deep in finalizing certification,\u201d Horne said.<\/p>\n
But it could take a little longer than the Space Force or ULA planned to sign the final paperwork to close out the certification process.<\/p>\n
Engineers from ULA, booster supplier Northrop Grumman, the Space Force, the National Reconnaissance Office, and NASA are participating in the inquiry into the nozzle malfunction. Last week, a ULA spokesperson told Ars the company recovered fragments of the nozzle that fell from the rocket near the launch pad to aid in the investigation.<\/p>\n
\u201cI think, when folks zoom in on the video, they see thrust, hot gas burn-through, potentially, in the bottom of the rocket section,\u201d Horne said.<\/p>\n