In article om,
says...

On 2015-12-30 08:52, Jeff Findley wrote:

The service module test article, provided by ESA, is at NASA's huge
vacuum testing facility (here in Ohio) right now.

Is that a fully functional one ? I read somewhere that the first service
module is basically a mockup with limited functionality to test the
mounting on rocket etc.

It's a structural test article. But as I said, I believe that ESA's
flight proven ATV (ISS cargo delivery vehicle) is the basis for the
Orion service module, so it's not like ESA is creating something
completely new.

The service module will no doubt be ready for its first test flight by
the SLS first flight.


So if Service Module is critical to ensuring re-entry after orbital
insertion, would they send a crewed Orion atop the first service module
flight ?

No, the first flight for the service module will be the unmanned. This
will be the second Orion flight (if you count the test flight that flew
on Delta Heavy as the first) and the first SLS flight (with an interim
upper stage based on Centaur).

With a limited number of available refurb shuttle engines, they can't
afford to have too many test flights if they wat to have at least one
crewed flight before they run out of engines.

They plan on making more engines. A cost reduced version of the SSME
which is more suitable for an expendable launch vehicle than the
original (presumably more expensive to manufacture) SSME.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer