Author Topic: SPECIAL EVENT: George Sowers - ULA VP for Human Launch Services - Q&A  (Read 64548 times)

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
Quote
I don't know the reputation of Ford vs Chevy to understand any nuance you might have been trying to convey there, but it's not the difference between having redundant systems and not having redundant systems, it's the question of if you do it through multiple identical units, or via dissimilar systems that perform the same function.

Ford and Chevy are classical automotive rivals. They are "dissimilar systems that perform the same function".  Maybe the rocket analogy fails.  Could an F9 be used to launch the same thing a DIV could?
Sometimes I just flat out don't get it.

Offline WHAP

  • Member
  • Full Member
  • ****
  • Posts: 795
  • Liked: 104
  • Likes Given: 8
Quote
I don't know the reputation of Ford vs Chevy to understand any nuance you might have been trying to convey there, but it's not the difference between having redundant systems and not having redundant systems, it's the question of if you do it through multiple identical units, or via dissimilar systems that perform the same function.

Ford and Chevy are classical automotive rivals. They are "dissimilar systems that perform the same function".  Maybe the rocket analogy fails.  Could an F9 be used to launch the same thing a DIV could?

That's starting to drift from the original discussion.  If a given spacecraft wants to have a backup capability, they could contract with two launch providers, as often occurs.  The point being discussed was that ULA, with Common Avionics, would have increased risk of having to stand down both Atlas and Delta if an issue occurred on one vehicle due to the increasing commonality between the two.   
Of course, with any separation at all, ULA is "better off" by having two "partially different" launch vehicles than a single vehicle.  That's not because payloads originally plannng to launch on Atlas could fly on Delta if Atlas had to stand down for an anomaly, but because the payloads already planning to fly on Delta could keep flying if the issue did not affect both launch vehicles.  Moving payloads from one EELV to the other is a nice concept, but in practice requires a fair amount of integration to occur in advance and may even require hardware modifications to the launch vehicle depending on the spacecraft.
ULA employee.  My opinions do not necessarily reflect those of my employer.

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
The point being discussed was that ULA, with Common Avionics, would have increased risk of having to stand down both Atlas and Delta if an issue occurred on one vehicle due to the increasing commonality between the two.   ...

Moving payloads from one EELV to the other is a nice concept, but in practice requires a fair amount of integration to occur in advance and may even require hardware modifications to the launch vehicle depending on the spacecraft.

Stretching the automotive analogy a bit, perhaps a Ford engine could be used in the Chevy pickup?

Regarding the Common Avionics; they would need to be very reliable, to the point that a standown would be unlikely on the basis of this part.  Perhaps an individual part would fail, but the product line would be very reliable.  Back to the auto analogy a bit; within a wide range of suppliers, tires are extremely reliable, and not seen as a part which would necessarily cause a standown of the vehicle.  The case of Firestone tires does come to mind, and a number of vehicles were recalled to replace that faulty product.  Quite realizing that a tire and an avionic system are worlds apart in complexity.

Can't systems be tested to the point where reliabilty is assured, even when used on different LV's such as Atlas and Delta?
Sometimes I just flat out don't get it.

Online Chris Bergin

First article resulting from Dr Sower's comments (he was aware I was going to convert his comments into articles):

http://www.nasaspaceflight.com/2012/08/ula-experience-to-build-culture-atlas-v-crew-safety/

Comments specific to the article should be posted in the article's thread on the commercial crew section:
http://forum.nasaspaceflight.com/index.php?topic=29796.0

Tags: