Author Topic: ULA Vulcan Rocket Q&A with ULA's Dr. George Sowers - April 14, 2015  (Read 96557 times)

Offline Robotbeat

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I'd like to know more about any plans for depots and the extremely long-lived side of ACES. You mentioned months. Does this include some sort of sunshield? Can I sneak one in on second stage recovery?
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Offline davey142

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Dr Sowers,
Thank you for taking our questions. With the addition of more powerful solid rocket motors, I would like to know how the acceleration profile during flight will compare to that of the Atlas V / Delta IV now. Will the acceleration be higher? Or has this been offset by other factors?

Offline Borklund

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ULA is not its own company.  Is this development being done on ULA funds or have the parent companies okayed it?
I believe this was already answered at yesterday's webcast: "Funding for development is completely out of ULA's profits."


Thank you for doing this Dr. Sowers. I have a simple question: Will the stars and stripes paint scheme go on production vehicles or is it just artistic license for the renders? I think it looks gorgeous. Thanks, and I look forward to the first Vulcan launch!

Offline deltaV

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ULA's press release says "In step two, the Centaur second stage will be replaced by the more powerful, innovative Advanced Cryogenic Evolved Stage (ACES), making the NGLS capability that of today’s Delta IV Heavy rocket.". Qualitatively will Vulcan with ACES match or exceed DIVH to all destinations from LEO to Saturn or will it be better for some orbits but not others? Quantitatively what's Vulcan with ACES's expected payload mass to LEO, 1500 m/s GTO, TLI, Mars, and Saturn? (Or better yet a plot of mass vs C3.)
« Last Edit: 04/14/2015 05:28 am by deltaV »

Offline Galactic Penguin SST

Dr Sowers - are there any concepts discussed on how the 1st stage engine booster inflatable heat shield will be made of and tested for use?
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Dr Sowers; thank you for all your attention and time here. Question: might any ACES derivative be put forward as a possible 'Exploration Upper Stage' for the SLS?
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Offline redliox

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Dr. Sowers,

My first question is the fuel choice for the first stage: methane.  What prompted the use of methane as opposed to the more traditional kerosene?

My second question is how much payload could the first configuration of Vulcan (with Centaur as upper stage) put into orbit or even to Mars?  The later part of the question relates to ULA's history with sending space probes out such as MAVEN and even Pluto-bound New Horizons.  The size of such spacecraft ultimately depend on the capabilities of the rockets that launch them.
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Offline ChrisWilson68

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SpaceX has said their goal is to fly first stages back to the landing site and reuse them quickly -- gas and go.  If SpaceX is successful in that, and continues an unbroken string of Falcon 9 launch successes, can Vulcan compete with that?  Or is ULA betting the company that SpaceX will fail?

Offline Steven Pietrobon

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Dear Dr. Sowers,

Is ULA considering the use of propellant densification via subcooling of the Vulcan first stage propellants as a way of increasing the performance of the vehicle?

All the best, Steven.
« Last Edit: 04/14/2015 08:08 am by Steven Pietrobon »
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Offline dglow

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Dr. Sowers, congratulations on the Vulcan reveal!

Of the components and technologies announced and/or discussed today, which one most excites you personally, and why?
« Last Edit: 04/14/2015 10:38 am by dglow »

Offline FutureSpaceTourist

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Dr Sowers, thank you for taking the time and trouble to answer questions.

How long have you been working on the Vulcan concept and what approximate stage in development have ULA reached? (eg PDR, CDR etc)

Offline Lar

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Another vote of thanks for agreeing to take questions, Dr. Sowers!

ULA surely did trades on full first stage recovery versus engine compartment midair... why is midair recovery so compelling, compared to the path SpaceX is on, which seems to offer the promise of far greater cost reductions?
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Offline spacediver

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Dr. Sowers

AFAIK the current ULA launchers were only used to launch NASA or USAF payloads.
Does ULA plan to (re-)enter the market of commercial comsat launches with Vulcan?


Offline JasonAW3

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Dr. Sowers,

     If ULA is planning to attempt either full stage or Engine and Avionincs package recovery, whatis the particular method that you have in mind for such recovery?  Powered descent to land, Parachute to sea, or a combination of these strategies?
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Dr. Sowers' limo has been spotted in the NSF Towers car park, so he'll be answering questions shortly. :)

Let's have a freeze point for questions to allow him to catch up.

Offline georgesowers

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Dr. George Sowers - VP, Advanced Concepts and Technologies (new rocket development is within his department) has kindly agreed to take questions on the NGLS (Named Vulcan) that was revealed April 13.

Dr. Sowers is a great friend of the site and has provided some superb Q&As here, for which we're very grateful.

I'm opening this now, ahead of Dr. Sowers answering questions on Tuesday, April 14, MT.

One question per member to ensure Dr. Sowers isn't overloaded with questions. Ensure your question is well presented, readable and worthwhile and please read the coverage of the reveal here: - to ensure you don't ask a question already addresses (or that you ensure it asked for clarification of an answer).

Before I dive into the questions, I'd like to thank Chris for giving me the opportunity to do this Q&A.  As I wrote in a recent op ed ( ) developing new rockets is a good as it gets for someone in our business.  It's clear that all of you share my enthusiasm.  And that makes answering your questions really fun.

Offline georgesowers

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All best with the Vulcan. It has turned me into a ULA fan and many others judging by forum activities and name voting.

Do ULA plan to introduce IVF on Centuar or will it wait for ACES?.

Business case to close. 
Thanks!  As Tory said in the press conference, we got well over 1.1M votes.

IVF is an integral part of the ACES design.  We would like to field it on Centaur earlier, but need to find the right opportunity to get the business case to close.  Without going into details, we are actively pursuing several possibilities.
« Last Edit: 04/14/2015 02:42 pm by Chris Bergin »

Offline georgesowers

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Hi Dr. Sowers,

Thanks very much for doing this with us. Can you talk about any timelines or capabilities for Vulcan human launch? That wasn't touched on at all during the press conference, but with CST-100/Atlas making a lot of news, I'm sure things like pad access etc are in the works.

Thank you.

It's our plan that Vulcan will be human rated.  We are incorporating human requirements from the outset and involving the commercial crew office in the development process.  For example, we have constrained the height of the vehicle to maintain the CST-100 interfaces at the launch site unchanged as well as the interfaces to the Centaur.  How and when we transition from Atlas to Vulcan will be worked in collaboration with our Boeing customer and NASA.

Offline georgesowers

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Thank you Dr. Sowers for your offer of answering NGLS/Vulcan questions.

If you and your rival are equally successful at your respective first stage "reuse" strategies, how well will they compete in terms of increasing overall annual launch frequency of each vendor?

Thank you again in advance for answering my humble question.

An excellent question.  The answer is: it remains to be seen.  Increasing launch rate means increasing launch sales which means getting new customers.  That can happen in two ways: take customers away from someone else (via lower prices) or generate new demand.  We all hope for the later.

The challenge for reuse has always been with the business case.  Can you get the cost of recovery and refurbishment low enough to truly save money?  No one has done it yet.  We believe the approach outlined yesterday gives us the best shot at it.

BTW, I have a simple parametric spreadsheet that runs through the economics as a function of number of reuses, and the various relevant cost parameters.  When I get some more time, I'll post it here and let you guys have fun.

Offline georgesowers

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Thank you Dr. Sowers for the opportunity.

My question is whether the vehicle (or a specific configuration) be rated for nuclear payloads (IE: science missions with Plutonium)?

Currently, Atlas is the only LV in the US fleet that has carried nuclear payloads (Pluto New Horizons and Curiosity).  We are quite familiar with the process and expect Vulcan will eventually carry nuclear payloads.  The process is done on a mission specific basis.  There is no blanket nuclear certification to my knowledge.