Re: Ares vs DIRECT

On Wed, 5 Dec 2007 11:21:09 -0800 (PST), in a place far, far away,
behlingjo@xxxxxxxxx made the phosphor on my monitor glow in such a way
as to indicate that:

It has cause problems for the companion spacecraft: Syncom-IV-3,
GRO, SPARTAN and some unmentionables are some

How does sharing a ride with a crew "cause problems"?

The shuttle was "manrated" just not completely on all systems.

Spacecraft that flew on the shuttle had extra inhibits and valves and
heavier structure (increased factors of safety). This prevented
Syncom IV and the Spartan from activating. GRO had a latch that hung
up on an antenna when a pyro type device would have been more
reliable. There have been others

I'm quite familiar with that. I used to work closely with the payload
integration folks in Downey. That was to protect the Orbiter itself,
and had nothing to do with actual man rating, regardless of whether or
not NASA chose to call it that (perhaps you don't understand what "man
rating" actually is?). Even without crew, you'd have done the same
thing on any reusable vehicle, because the vehicle is such a costly
asset.

Launch vehicles are not airliners because
1. LV are not as reliable

Irrelevant to the point.

2. LV don't have as many graceful "abort" options. Abort towers are
more like ejection seats

Again, irrelevant to the point.

3. airliners don't carry anything as large and hazardous as a fueled
spacecraft.

I wasn't referring to a "fueled spacecraft." We were referring to
"cargo" (e.g., logistics resupply for ISS).

4. There is nothing "routine" about an LV launch

Again, irrelevant to the point.

5. Margins in LV systems are less than airliner

Again, irrelevant to the point.

Simple reliability analysis rule of thumb: More parts is less
reliable

More parts exist with the cargo because:
1. the cargo itself is made up of parts and it is not passive
2. The LV must accommodate the cargo in addition to the crew, this
requires more parts

It doesn't require "more parts." It just requires a larger payload
cannister.

Defintion: Cargo is not just ISS logistics or assembly

Then you're simply defining the problem away.

All of your arguments are arguments against launching *some* types of
payloads along with crew. That's a straw man, since no one has argued
that every conceivable payload should be able to share a ride with
crew. They're not arguments for *never* launching cargo with crew,
related or otherwise.

Talk to any one who has worked on a spacecraft that flew in the
shuttle. It was a pain in the ass

Of course it was. But you cannot draw broad conclusions from a single
example. This is called the fallacy of hasty generalization, and one
that many people indulge in when it comes to "lessons" "learned" from
the Shuttle. The notion that we should never mix crew and cargo is
just one of many such false lessons.
.

Relevant Pages

  • Re: ESAS "1.5 EOR" Architecture Finished?
    ... The shuttle was a bit of a committee design, ... with manning the cargo launcher. ... And if there is the slightest chance that having a crew aboard ... EPG0830 The responsible program should separate crew from cargo for launches ...
    (sci.space.policy)
  • Re: Ares vs DIRECT
    ... The very idea that separating crew from cargo for ISS missions is silly to ... If your launcher is big enough, you stick the cargo under Orion and fly ... combining of crew and cargo - but they didn't think the issue through fully. ... There is a massive difference between including a payload bay inside ...
    (sci.space.policy)
  • Re: EOR with Stick
    ... >> As for crew and cargo, ... that crew should be separated from cargo. ... The thinking was that, since shuttle had ... going to be launch of the GPS satellite constellation! ...
    (sci.space.policy)
  • Re: EOR with Stick
    ... >>> As for crew and cargo, ... that crew should be separated from cargo. ... The thinking was that, since shuttle had ... >going to be launch of the GPS satellite constellation! ...
    (sci.space.policy)
  • Re: Ares vs DIRECT
    ... The shuttle is unique because payloads were carried *in* the shuttle. ... Anything inside the payload bay was a potential threat to the orbiter itself ... payload capacity that you can stick cargo *underneath* the Orion spacecraft. ...
    (sci.space.policy)
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