ULA updates Vulcan status, readiness for certification missions

by Chris Gebhardt

Development and flight qualification for United Launch Alliance’s new rocket, Vulcan, remains on track and on schedule (with margin) to make its debut flights next year, as do all ground support facilities and flight software elements for the heavy-lift vehicle.

Vulcan’s first two flights, certification missions to clear the rocket to fly category A/B national security payloads for the U.S. Space Force, will loft Astrobotic’s Peregrine Lander outward to the Moon and then Sierra Nevada’s Dream Chaser spacecraft on its demonstration mission for NASA to become the third U.S. cargo vehicle for Station operations.

Ground elements:

It’s coming up on six years since we really started full-scale development,” said Mark Peller, VP of Major Development for ULA in a one-on-one interview with NASASpaceflight.  “We’re a year and a half past [Critical Design Review].  So we’ve gone through all the design and analysis phase of the program, and now we’re in the process of going the other way and building hardware and going through all the tests and verification as we head toward first flight next year.”

But a significant part of that buildup is not taking place at the Decatur, Alabama, facility — where Vulcan is being primarily constructed — but rather down at the Cape Canaveral Air Force Station in Florida where launch facilities are being prepared for the vehicle.

“All the modifications that we’re making there on the east coast are back compatible to Atlas, so we can launch a Vulcan and literally within a day we can reconfigure and start processing an Atlas or vice versa,” said Mr. Peller.

An artist’s concept of Vulcan lifting off from SLC-41 at the Cape Canaveral Air Force Station, FL. (Credit: ULA)

“One of the key elements of the architecture on the east coast is the Mobile Launch Platform.  We decided to build a new one dedicated just to Vulcan that would really support parallel operations and could be designed really without compromise to support the Vulcan rocket.”

The primary element of the Mobile Launch Platform was completed last year and has been undergoing outfitting operations for its fuel, pneumatic, electrical, and hold down elements that will support and interface with Vulcan.

“We’re nearing completion,” noted Mr. Peller. “Later this year, we’re going to take it out to the launch pad and hook it up to all the ground systems.  And we’ll do cryo flow and pneumatic testing.  And all of that is in preparation for when we do that with a vehicle on top of it.”

At SLC-41, work to upgrade the pad to add Liquefied Natural Gas (LNG; in this case, liquid methane) storage and distribution capabilities as well as increase the liquid hydrogen and liquid oxygen commodities at the pad has also gone well.  

Some of that work (pneumatics, sound suppression, additional liquid hydrogen/liquid oxygen tanks) is complete and has already been used successfully on Atlas V missions.  The remaining Vulcan-specific work (LNG tanks and distribution) is on track for completion this autumn ahead of Mobile Launch Platform verification and validation testing.

However, while SLC-41 can support dual use and overlap between Atlas V and Vulcan, the same cannot be done for the west coast facility of SLC-3E at Vandenberg Air Force Base, California. 

The ability to co-fly Atlas V and Vulcan from SLC-41 at Cape Canaveral is due to the Mobile Launch Platform design of the pad, allowing the two vehicles to share certain commodities while each having their own launch platforms sized for their individual needs. 

An Atlas V lifts off from the Fixed Launch Platform at SLC-3E at Vandenberg Air Force Base on the NROL-79 mission. (Credit: ULA)

SLC-3E at Vandenberg employs a Fixed Launch Platform and therefore cannot be modified in a way that would allow Atlas V and Vulcan to overlap in California.

“The infrastructure there is different, so it has led to a different approach to how we conduct the modifications,” noted Mr. Peller.  “The long and short of it is that we have elected to do a hard cut over.  So we will start the modifications and start putting the capabilities in place for Vulcan [as Atlas keeps flying], but we will get to a point where we will just need to make a hard cut over.”

Some of the work that can be done in parallel with Atlas V operations from Vandenberg, which will continue into 2022, include installation of the new LNG tanks and distribution system as well as upgrading the liquid hydrogen and liquid oxygen commodities to support the larger Centaur V upper stage of the Vulcan compared to the Common Centaur (Centaur III) used by Atlas V.

Modifications to the mobile servicing tower can also be made at SLC-3E, but it will ultimately come down to the launch stand for when the hard cut over will need to occur.

“Because we don’t use a Mobile Launch Platform but a Fixed Launch Platform, we will build that up offline or in pieces and then at the point that we make the hard cut over we will install the Fixed Launch Platform that will be developed exclusively for Vulcan,” said Mr. Peller.

Vulcan’s west coast debut is anticipated in 2023.

The hard cut over between Atlas V and Vulcan — and the need to take SLC-3E offline to make the final change — is made possible due to the low flight rate demand for missions that have to launch from Vandenberg Air Force Base.

What’s more, as Vulcan will have an Automated Flight Termination System (AFTS), it will be eligible to fly polar missions using the southern polar launch corridor reestablished by the U.S. Air Force (now managed by the U.S. Space Force) to enable polar launches from Cape Canaveral.

This could help ease ULA’s need for Vandenberg for certain polar missions during SLC-3E’s down time.

The only stipulation for eligibility to fly polar missions from Florida is that the rocket must have an AFTS.

Atlas V and Delta IV will also have to switch to AFTS sometime in 2021 to satisfy the Eastern Range’s regulation that all rockets (except NASA’s SLS) must use AFTS beginning in 2022.

Keeping with Florida, ULA only plans to operate the Vulcan from SLC-41 and has no plans to modify SLC-37B to accommodate the vehicle following the retirement of the Delta IV line in 2024. 

“All of our Vulcan plans are focused around [SLC-41] and similarly on the west coast around SLC-3E.  If [flight] rate increases, we have options to make further investments to increase the throughput through those two facilities,” added Mr. Peller.

Ground and flight software:

A significant benefit to the software development for Vulcan is the common avionics system employed by United Launch Alliance (ULA) across its rocket fleet — a system that has been brought over to Vulcan. 

“Several years back, we converted Atlas and Delta to a common airborne and ground electrical system, or avionics, and common ground software,” said Mr. Peller.  “And that was a significant investment; it has worked out very well for us to refresh those systems and use them with the latest technology.  And we’re carrying that over to Vulcan.”

While some modification is necessary for Vulcan, Mr. Peller noted that the same basic structure of the ground software, the backbone of what’s used for the launch countdown, is the same — with some specific elements modified to reflect Vulcan’s uniqueness. 

This is the identical process ULA follows with the same common ground software also employed for both Atlas V and Delta IV countdowns.

Overall, between Atlas V, Delta IV, and Vulcan, 85% of the avionics suite is identical between the vehicles (meaning the same avionics box could finish assembly and be installed — without modification — on any of ULA’s three rockets).

Only about 15% of avionics hardware on each rocket is different based on the unique configuration of each vehicle.  The same is true for the ground and flight software: about 85% of the software used by ULA for countdown and flight is identical between the vehicles.

“Basically we have to update 15% of the flight program,” said Mr. Peller.  “But we do it in a way that it’s the same flight program no matter if you’re flying an Atlas or Vulcan.  So we can initialize a specific set of parameters on a given day and go fly an Atlas or Vulcan.  So that also helps us with verification … and maintenance of our software to have one set of flight software fly all three of our rockets.”

This also enables ULA to continue using their common launch team, which is aided in the software commonalities between the vehicles.

Some launch team positions will be specialized to Vulcan (as they are now to Atlas V and Delta IV), such as the Chief Engineer for each of the rockets and some of the engineers and technicians who work directly with them.  But the main part of the team will be able to move back and forth between vehicles during the period when Atlas, Delta, and Vulcan are all flying. 

Vulcan test and flight hardware:

While the long pole item for Vulcan remains the various hardware elements that need to be fabricated and integrated before the vehicle can make its inaugural flight, Mr. Peller noted that schedules are currently on track and contain margin to meet the anticipated two missions next year for the Peregrine Lunar Lander and Dream Chaser.

Vulcan liquid oxygen tank for the first flight vehicle. (Credit: ULA)

Hardware for the second Vulcan mission is already in fabrication at the Decatur, Alabama, facility in parallel to continued production of first flight hardware.

In terms of Vulcan and Centaur V fabrication and testing, “So far [it’s been] pretty straightforward.  We have a lot of experience and previous analytical tools.  So no big surprises out of our fluids or structural tests.  They’ve gone pretty smooth.”

Presently, ULA is in the process of qualifying the structure for Vulcan’s mainstage booster.   “We finished that test article last year, and we’re testing at the Dynetics facility in Decatur, Alabama.  And that will wrap up later this year.”

For the Centaur V upper stage, two test articles are being used — one for structural and the other for fluid loading qualification and to allow ULA to “get some experience loading propellant onto the enlarged Centaur upper stage,” noted Mr. Peller.

All systems and structural testing is anticipated to end before the close of the year.  Mr. Peller noted that even if some of that testing were to stretch into the early part of next year, it would still support the ability to fly in the middle of 2021.

The two RL-10-1-C engines that will power the first Centaur V are slated to be delivered to ULA from Aerojet Rocketdyne in autumn.


On Thursday, 13 August, Northrop Grumman successfully test-fired a GEM-63XL solid rocket motor for Vulcan at their Promontory, Utah, test facility.  The first of two qualification ground firings, the second is expected to follow before the end of the year and wrap up qualification on the new solid rocket motor.

A GEM-63XL undergoing the first qualification firing to certify the design for Vulcan. (Credit: Northrop Grumman)

Mr. Peller noted that the first qualification firing was immensely successful and that Northrop Grumman has started to “wind and cast the production Vulcan motors for the inaugural launch next year.”


In particular, Mr. Peller noted the progress with development and testing Blue Origin has achieved with a BE-4 engine while voicing his affirmation that engine development remains on schedule and with margin for ULA to accept the first set of flight engines by the end of the year and to support the first flight in the middle of next year.

“[The BE-4] engine was first hot fired about three years ago, and Blue Origin has been making great progress with development and testing various elements and engines at their West Texas test site to work out the design,” said Mr. Peller.

Speaking to the Denver Business Journal yesterday, ULA CEO Tory Bruno noted an ongoing issue with BE-4’s turbopumps but voiced his confidence that the issue would soon be resolved and that it would not impact Vulcan’s schedule at this time.

Speaking to NASASpaceflight on the same day, Mr. Peller independently affirmed that no schedule impacts from the BE-4 are currently being tracked, stating “They are actively building, in their Kent facility, the [qualification engines] as well as the first flight engines.  Later this year, we’ll also take delivery of the first flight engines for buildup of the first booster to support the Peregrine mission.”

Mr. Peller added that Blue Origin is nearing the end of the development phase for the BE-4 engine, espousing that if there’s been a good development process, qualification usually goes well.

“Development is really the hard part because that’s where you work out all your issues, at least that’s my experience.  Once you get into qualification with the engine, if you had a solid development program behind you, those usually go pretty smoothly,” noted Mr. Peller.

Development of the BE-4 has long been seen as the critical path for Vulcan.  ULA exercised an option within the U.S. Space Force’s National Security Space Launch (NSSL) Phase 2 award proposal and bid Atlas V as a backup vehicle for Vulcan in case the latter ran into development or certification issues.

When asked when ULA would have to inform the Space Force of its desire to switch one of the first awarded NSSL missions from Vulcan to Atlas V under a purely hypothetical BE-4 or Vulcan issue, Mr. Peller did not comment directly, instead affirming ULA’s confidence that all of their NSSL missions would fly on Vulcan.

“BE-4, they’ve made really good progress with development.  And they’ve really demonstrated all the fundamental technologies.  And all the things that all the people were concerned with years ago with propellant and the fuel and the ability to develop, domestically, a large oxygen-rich combustion engine and some of the other really novel technologies that are key to enabling BE-4 and its performance, we’re through all those.

“We’re into just working out the final details and have kind of moved on to production and qualification of hardware.  We’re on track and have the necessary margin in our schedules.”

Composite structures (intertank, fairings, dual launch canister, payload fitting adaptor)

Lastly, but certainly not least, all of the composite structures for Vulcan are progressing to plan, including construction of the test articles for a dual launch canister, Payload Attach Fitting, the fairings, and the interstage.

“There are up to five major composite structures on the Vulcan rocket depending on what configuration of the rocket we fly — from the payload fairing to the Payload Attach Fitting to the interstage and the heat shield and in some cases a dual launch canister,” noted Mr. Peller.  “And those are being developed by RUAG and produced domestically.”

A model of Dream Chaser inside the Vulcan fairing – by NSF’s Lee Jay Fingersh

RUAG previously built the payload fairings for Atlas V in Switzerland and transported them to the U.S.  Now, RUAG has moved that process to the U.S. and co-located with ULA in their Decatur, Alabama, production facility.

The new composite fairings that will be used for Vulcan are also now being employed in the manufacturing process for Atlas V fairings. 

“That’s also another example of something that will fly on Atlas first.  So we’ll actually fly a new composite RUAG fairing built with the different processes … on Atlas later this year or early next year,” said Mr. Peller.

(Note: Due to time constraints for the interview, questions about the status of SMART reuse, the ACES evolution of the upper stage, and Vulcan Heavy status were asked via email follow up.  Those answers are pending from ULA; this article will be updated when that information is available.)

Lead image: Mack Crawford for NSF/L2.

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