Orion Justification

On 4/16/2010 9:53 AM, Rick Jones wrote:
Pat wrote:
Orion can carry six astronauts, Soyuz only three. So you need two
Soyuz to evacuate the whole ISS crew, but only one Orion.

Eggs and baskets

Yeah, I guess you could either consider that the choice between upping
the chances you will lose a six-person crew, or upping the chances you
will lose three of them, depending how you look at it. ;-)
One thing is for sure; trying to cram six of them into one Soyuz RV in a
emergency is probably a non-starter, given the somewhat cramped nature
of the capsule's interior:
http://s88.photobucket.com/albums/k1...side-front.jpg
Maybe if they took their pressure suits off and sat on each other's laps?

Pat

On 4/16/2010 11:37 AM, Anthony Frost wrote:


Although with only one Orion, you *have* to evacuate all the crew
whatever the reason. You lose the option of just returning an injured
crew member and next two in the rotation while leaving the other three
to carry on.

I hadn't thought of that, but it's a very good point.
The two-Soyuz concept actually makes more sense in that regard.

Pat

On Apr 16, 6:25*pm, Pat Flannery wrote:
On 4/16/2010 2:01 PM, Neil Fraser wrote:
The problem is, this requires both Dragon and Falcon 9 to be successful.
If we build Orion Light, we can stick it on Delta IV Heavy or Atlas V
and at least know that the booster will work.
I imagine you could stick Dragon on either of those boosters also, but
if Falcon 9 flops, will SpaceX continue Dragon development?

Ok, given the scenario where Dragon/Falcon (and all competition flops)
then what's the point of the Orion Lite lifeboat? The astronauts
would have had to come up on a Soyuz -- which would therefore be
docked and serving lifeboat duty. The only need I can see for a
dedicated lifeboat is if the vehicle which brings the crew to ISS in
the first place is unable to hang around in space for six months. The
Space shuttle is the only such vehicle.

On 4/16/2010 11:00 AM, Jeff Findley wrote:

Dragon will initially be unmanned. Who knows how long it will take SpaceX
to build a manned version which meets NASA's "man-rating" specifications.

Yeah, but in a emergency if your choice is between riding down in a
non-man rated Dragon cargo RV or dying in space, you will probably pick
the Dragon.
The lack of form-fitting crew seats for the G loads of reentry will be
offset by the cushioning effect of the thick layer of crap in their
pressure suit pants. ;-)

Pat

Neil Fraser wrote:
On Apr 16, 5:40 pm, Pat Flannery wrote:
I hadn't thought of that, but it's a very good point.
The two-Soyuz concept actually makes more sense in that regard.

But this still doesn't addres what the point of the Orion is.

The Russians will continue to service their three cosmonaut slots
using a rotating series of Soyuz craft. So they are accounted for in
terms of evac needs. Once Dragon (or others) comes online, the
Americans will stop using a second Soyuz, and start using a rotating
series of Dragon craft. So they are accounted for in terms of evac
needs.

Who's left? Everyone has a seat. Who are the mystery travellers who
need the six-seats on Orion Lite? Did Canadarm2 become sentient and
now requires emergency evac in case of fire?

True, but it does give you more options such as flying up 2 and extra
goodies.

But ultimately, I think it's a sop to potential commercial vendors.
Sorta like flying airmail contracts even though at the time trains were more
reliable and for some routes arguably faster.



--
Greg Moore
Ask me about lily, an RPI based CMC.

On 4/16/2010 1:59 PM, Brian Thorn wrote:

That assumes Dragon will be able to stay at ISS for 180 days. Will it?
If not, it is just a taxi and we need a lifeboat.

The DragonLab version is supposed to be able to stay up for two years
before reentry: http://www.spacex.com/downloads/dragonlab-datasheet.pdf
So they should be able to make Dragon stay usable for six months.

Pat

On 4/16/2010 2:01 PM, Neil Fraser wrote:

Who's left? Everyone has a seat. Who are the mystery travellers who
need the six-seats on Orion Lite? Did Canadarm2 become sentient and
now requires emergency evac in case of fire?

The problem is, this requires both Dragon and Falcon 9 to be successful.
If we build Orion Light, we can stick it on Delta IV Heavy or Atlas V
and at least know that the booster will work.
I imagine you could stick Dragon on either of those boosters also, but
if Falcon 9 flops, will SpaceX continue Dragon development?

Pat

On 4/16/2010 4:51 PM, Neil Fraser wrote:

Ok, given the scenario where Dragon/Falcon (and all competition flops)
then what's the point of the Orion Lite lifeboat? The astronauts
would have had to come up on a Soyuz -- which would therefore be
docked and serving lifeboat duty. The only need I can see for a
dedicated lifeboat is if the vehicle which brings the crew to ISS in
the first place is unable to hang around in space for six months. The
Space shuttle is the only such vehicle.

That's certainly the situation in a nutshell.
Soyuz has to be the "Jeep" of spacecraft, it's not ideal for any
particular task, but incredibly adaptable and versatile enough to
perform a whole plethora* of missions fairly well.

* Triple word score...I think that is the second or third time I've used
that word in writing in my entire life. The sucker has just been sitting
around in the back of my vocabulary, getting more covered in cobwebs and
dust as the decades moved on. ;-)

Pat

Pat

Neil Fraser wrote:
What is the justification behind resurrecting the Orion capsule as a
lifeboat? Normally the vehicle that brings the crew to the station is
also the vehicle that serves as the lifeboat. Reasons I can think of
a
* SpaceX and other commercial players are having trouble making their
capsules last for 6 months in space. Thus their vehicles would come
and go, leaving the crew to rely on the lifeboat.

A bigger reason is that SpaceX uses CBM for ISS berthing/unberthing
rather than a docking mechanism. CBM is unsuitable for ISS emergency
evac since the active side of the mechanism is on the ISS side (and
therefore requires ISS power) and requires the SSRMS to perform the
unberthing (way too slow for emergency evac, and requires a crewmember
to remain on ISS).

SpaceX has shown concept drawings of Dragon with a LIDS mechanism, but
offloading the CRV function to Orion relieves them of the expense of
developing and maintaining a second variant, as well as relieving them
of the six-month stay requirement.

* An insurance policy in case commercial players fail to provide a
vehicle. In this case NASA could refit the lifeboat with an escape
tower for crew launch.
* A get-ahead for a later full-up deep-space version of Orion.

Yes. Essentially a return to "spiral development". Spiral 1 is CRV,
spiral 2 could be either a full-up beyond-LEO CEV or an ISS CTV
depending on whether ISS Commercial Crew succeeds.

The original Obama proposal was loosely based on Augustine Option 5B
(ISS Commercial Crew, Orion for beyond-LEO exploration in the 2020s),
with the rather major difference that the Obama proposal cancelled Orion
along with the rest of Constellation. Without Orion, the plans for
beyond-LEO exploration lacked credibility. Keeping Orion around as a CRV
keeps the development and operations teams together and keeps future
options open.

* A jobs program to placate the recent protests and lobbying.
* A result of huge contract termination penalties which make
completing Orion Lite about the same cost as cancelling it.

The administration is following the same political strategy as on the
health care bill. Propose a radical plan, identify the opponents that
are "wobbly", then propose just enough compromise to buy their support
(or at least neutralize their opposition). Wash, rinse, repeat until you
have enough votes.

The Orion CRV compromise just bought Colorado (1000 L-M jobs in
Littleton) and neutralized some of the opposition in Texas (Orion
Project Office and mission operations) and Florida (Orion vehicle
processing).

The administration probably has enough votes now to ram this through but
that would require political capital that they wouldn't want to squander
on a small issue like space. I expect one more round of compromises
(possibly a modest shuttle extension, a stronger commitment to
"evolving" the Orion CRV into a CEV or CTV later, or further
acceleration of the HLV decision) to grease the skids, especially in
Florida.

Neil Fraser wrote:
On Apr 16, 6:25 pm, Pat Flannery wrote:
On 4/16/2010 2:01 PM, Neil Fraser wrote:
The problem is, this requires both Dragon and Falcon 9 to be successful.
If we build Orion Light, we can stick it on Delta IV Heavy or Atlas V
and at least know that the booster will work.
I imagine you could stick Dragon on either of those boosters also, but
if Falcon 9 flops, will SpaceX continue Dragon development?

Ok, given the scenario where Dragon/Falcon (and all competition flops)
then what's the point of the Orion Lite lifeboat? The astronauts
would have had to come up on a Soyuz -- which would therefore be
docked and serving lifeboat duty. The only need I can see for a
dedicated lifeboat is if the vehicle which brings the crew to ISS in
the first place is unable to hang around in space for six months. The
Space shuttle is the only such vehicle.

Neil, why are you continuing to ask questions that *you* *yourself*
provided answers for in your initial post?

Without a dedicated CRV, *all* the ISS Commercial Crew vehicles would
have the six-month stay requirement levied upon them. With a dedicated
CRV, that requirement is relaxed and the Commercial Crew vehicles would
only be required to perform short-term rotation.