Re: NASA Encounters Problems With Ares 1 Launch Vehicle Design


"Pat Flannery" <flanner@xxxxxxxxxx> wrote in message
news:12lpugpe7qfhc58@xxxxxxxxxxxxxxxxxxxxx
mmaker@xxxxxxxxxxx wrote:
Pat Flannery wrote:
Even if you build Ares V, you are still going to have to
build something else to get crews to the ISS,

Why?

Because it's not economical for the crew/light cargo mission - each Ares V
is going to cost at least twice as much as a Ares 1 due to it using two
SRBs and having a far bigger two-stage core assembly.

But it's big enough you could launch it twice a year (assuming six month
crew rotations) with the cargo you need for those six months. Plus it's the
fixed costs that dominate Ares. When you're talking about two ISS crew
rotations and possibly two lunar missions per year, the money "saved" by
using the smaller Ares I will likely never pay for its multi-billion dollar
development costs.

There's also the reliability factor to consider - with its two SRBs, Ares
V has a built-in SRB catastrophic failure probability that's twice that of
Ares 1

While I don't like SRB's, I'd rather see a vehicle with two four segment
SRB's than vehicles with five segments, simply because there is more
commonality between them and the current shuttle SRB's. A single five
segment SRB still seems like a bad idea from development and safety
viewpoints.

Which would make perfect sense if the extra running costs of taking the
truck to the store were lower than the cost of buying and running a car
to do the trip. Similarly, if the full cost of five Aries V launches
(including development, launch site maintenance etc) is lower than the
cost of four Aries 1 launches and one Aries V launch each year, then
launching crew on a launcher with twice the required payload capacity
makes perfect sense. It's quite conceivable that the costs of operating
two launchers rather than one could easily swallow up any savings from
one launcher having lower base costs per launch.

I depends on how many total launches you have in mind... if it's something
like ten or twenty, then maybe just going for Ares V makes sense as your
sole launcher.
If you end up with around 100 launches desired, of which only 20 need the
Ares V's lifting capability, then you probably end up saving money by
going the two booster route.

I think you're living in a fantasy world if you think NASA would need 80
Ares I launches. I think they'll never get past an average of four to six
manned launches per year (two to ISS and the remainder to ???), which means
a program that will run for something like 15 to 20 years.

If past experience is anything to go by, once made Ares 1 will end up
being used for a very long time and for missions that are unforeseen
nowadays. Imagine if you went back to the original Thor IRBM design team
and told them that around 50 years down the line, a much evolved version
of their missile would be landing rovers on Mars

Doubtful due to the way NASA has been running Saturn/Shuttle/Ares. It will
always remain a NASA only launch vehicle. Note that NASA was banned from
selling launches commercially after the Challenger disaster and the Air
Force will continue to use EELV's for their launches. Once bitten, twice
shy.

Even more so, if you use a semi truck to drive everywhere and then you
buy a small car for the trips where it 'doesn't make sense', and the
truck then spends most of the time sitting on your driveway, pretty
soon your wife will be nagging you to get rid of it. Just as it's much
easier for Congress to scrap an Aries V that flies once per year to
launch big payloads on mega-missions than to scrap an Aries V which
flies multiple times per year and is the only manned launcher you have.

The two problems with the annual mega-mission idea is that the
mega-mission can only go to one destination, and you've still got all that
upkeep and infrastructure to maintain in the other eleven months of the
year eating up your money, just like the Shuttle does when it's been
grounded.

How would Ares I/V avoid high infrastructure costs? It's looking to be a
very low flight rate system that uses much of the shuttle infrastructure but
will be supporting two launchers instead of one.

Also, I'm pretty sure this now takes two Ares V launches per manned Lunar
mission using the present weight Orion CEV and the promulgated Lunar
lander.
If we're not going to do the Lunar missions, then there's no reason to
build Ares V at all, because we intend to finish up our diminished ISS
with the Shuttle, and there's no real need for another station in the near
future after that.

If we don't go back to the moon, there's no need for Ares I either. A
reasonably sized capsule can be built to service ISS and can be launched on
an EELV. If you drop the lunar mission, the size of the service module
drops *considerably*. NASA looked at making a "tuna can" SM for the Apollo
CM for Earth orbit missions, but it was easier just to delete extra tanks
and hardware from the existing luanr design. Eliminate the lunar
requirements and the CEV goes back to being a "single use" sort of vehicle
that's a lot easier to make lighter.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)


.

Relevant Pages

  • Re: NASA Encounters Problems With Ares 1 Launch Vehicle Design
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  • Re: NASA Encounters Problems With Ares 1 Launch Vehicle Design
    ... V is going to cost at least twice as much as a Ares 1 due to it using two SRBs and having a far bigger two-stage core assembly. ... if the full cost of five Aries V launches ...
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