Minimal Cost/Development Orion SM

[FinalFrontier]

what's so hard about being civil to each other?

It's not that time of year.  ;-)

On the topic of minimal Orion SM designs, has there been any analysis since HEFT of what were called CTV-E and CTV-E*?  These were the designs that dropped the requirement of carrying crew during ascent, and for the simple -E variant dropped the requirement of supporting crew at all other than during re-entry.  (This assumed that Orion would be docket to at least an MMSEV whenever crew were aboard.)

I would guess there have been some as Orion is ongoing, and they did look at other options (for example the ATV-bus sm concept which has received serious attention).

Where the documentation for this would be is entirely different.

[Patchouli]

.. and with that comment Jim just made my ignore list. Jesus people, what's so hard about being civil to each other?

Here's where I disagree to an extent.


If someone says something, as if it is fact and they are certain its fact and it is in reality, total baloney, then I don't see the problem with somewhat strong language being used to point that out.

I think while Jim was rough, perhaps a bit too rough, he was in fact civil.


Also, if you start putting people on your ignore list your never going to see the full conversations that occur on here and are thus going to miss large parts of the discussion, however uncivil they maybe, and will thus be somewhat less informed than the rest of us. This is why I dislike this idea of an "ignore" option. Simply shying away from other people's opinions (and facts in some cases) is not a solution, neigh, it is in-fact part of the reason why we have the modern economic mess that we do, and no one on the hill is willing to solve it.


Ignoring people doesn't solve problems.

The comment was kinda out of line.
I think it was also was an insult to the engineers at Lockheed who felt at the time they had a better design.
In the an LM engineer's own words the lifting CEV was a Mars return reentry vehicle they worked backwards into a Lunar reentry vehicle.

The truth is Griffin and Horowitz simply wanted every last detail their way or not at all.

BTW my few million on aero testing probably is low ball but at most going to the older saved at most 150 to 200 million.
That's if you wish to have lots of arcjet time and maybe launch some models on sounding rockets to fill in the gaps in the CFD models with the new shape.
It also should be noted CFD back in 1966 was nothing like CFD modeling today.
The fastest machine during much of Apollo development was the CDC 6600 at 3MIPS a cell phone today is probably well over 100 times faster then this.
Super computers can be billions of times faster.
Sure the math is the same but the difference is the number of data points.
The proof new aero work is not insurmountable or even difficult enough to  drive up the cost of a project significantly is Space-X's vehicle yes it's a capsule but it's different enough new data was needed.
Now back on topic one issue I have with an ATV derived SM is bus standards.
Orion may look retro but the guts are all new and it's a project that was started almost a decade later.

Not sure what standards are used on Orion but Spacex made big claims about using modern high speed buses in their vehicles.

[QuantumG]

I think while Jim was rough, perhaps a bit too rough, he was in fact civil.

Yes, being a bit too rough is not being civil.

Ignoring people doesn't solve problems.

It's not a perfect solution but it makes the forum readable with a stable blood pressure, and if you really want to read their comments you can press the expand button.. typically done while cringing with anticipation that you will be metaphorically slapped in the face when you do so.

[pathfinder_01]

what's so hard about being civil to each other?

It's not that time of year.  ;-)

On the topic of minimal Orion SM designs, has there been any analysis since HEFT of what were called CTV-E and CTV-E*?  These were the designs that dropped the requirement of carrying crew during ascent, and for the simple -E variant dropped the requirement of supporting crew at all other than during re-entry.  (This assumed that Orion would be docket to at least an MMSEV whenever crew were aboard.)

By law Orion must be able to support a crew durring ascent(in order to act as back up for commercial).  So the CTV-E and CTV-E* do not save on the development of the crew ascent ability.

CTV-E* pretty much has the same requirments as Orion in terms of crew support, delta V ect...

CTV-E might be the cheapest option, but HEFT didn't like the trade(they wanted the longer ability to support the crew for in space aborts as well as the Delta V). CTV-E would only support a crew for a few hours(just enough the land no more).

[Jim]

It also should be noted CFD back in 1966 was nothing like CFD modeling today.
The fastest machine during much of Apollo development was the CDC 6600 at 3MIPS a cell phone today is probably well over 100 times faster then this.
Super computers can be billions of times faster.
Sure the math is the same but the difference is the number of data points.

You still don't understand, computational power is meaningless if you don't have a model.  There is little data for those velocities to make a model.

[Patchouli]

It also should be noted CFD back in 1966 was nothing like CFD modeling today.
The fastest machine during much of Apollo development was the CDC 6600 at 3MIPS a cell phone today is probably well over 100 times faster then this.
Super computers can be billions of times faster.
Sure the math is the same but the difference is the number of data points.

You still don't understand, computational power is meaningless if you don't have a model.  There is little data for those velocities to make a model.

I know there are gaps in the understanding of hypersonic flows at this point.

But if these gaps in understanding are as large as you say they are then this is research NASA needs to be working on.

Better computer models for supersonic and hypersonic flows would have applications far outside of HSF.

[Robotbeat]

We do indeed have better models, but hypersonics is much harder than typical subsonic CFD. Much more difficult to validate, too. The higher and faster you go, the further away from typical continuous supersonic CFD. You start having non-continuum effects and complicated dissociative chemistry and surface catalysis, etc.

That said, SpaceX had a successful reentry first try. I am confident NASA (or LM) could've done it quite successfully if another design had been chosen. People have given NASA grief about using an unnecessarily complex or high performance design for other projects, and this was a case where they could get a head start in development by having the shape already validated.

[alexw]

I know there are gaps in the understanding of hypersonic flows at this point.
But if these gaps in understanding are as large as you say they are then this is research NASA needs to be working on.

      As an illustration, NASA's Mars entry vehicles all derive from the Viking aeroshell shape. Indeed, they would like to do a lot of research on flows for other conditions -- inflatable heatshields, hypersonic retropropulsion, ultimately including flying a test-demonstrator mission into either Earth or Mars's atmosphere. Computational modeling, even in this age, is evidently not enough. High priority for the technology office. But funding, alas, is being spent elsewhere.
     -Alex

[sdsds]

I'm not sure how this thread which is nominally about the SM drifted into discussion of CM reentry aerodynamics!  But connecting the two isn't difficult:  what ties them together is the excellent project management that LM has done even when the customer has presented some challenging requirements changes along the way.

That's only my opinion/view of course.  (And everything below is only that too!)

As regards the CM shape, the Apollo shape was the super-smart choice at the time of the initial CEV proposal.  That's because back then the only view acceptable to NASA leadership was that the LV for the CEV was going to be easy to develop.  Thus the CEV was going to be on the critical path.  Thus it had to use the shape with least schedule risk.

Of course that's not how events turned out in practice.  The LV design that was imagined (stick; 4 seg; airstart SSME) never materialized.  And as the LV design morphed the CEV requirements did too.  Through all that the Orion project managed to make forward progress and as a result, when CxP was on the chopping block, they had a fine looking GTA that made Orion look to many analysts too good, and too far along, to cancel.

Note they also face a challenging period of requirements being rewritten when they survived CxP's demise only as the ISS lifeboat.  That mission would be low delta-v and low thrust (since now crew would be aboard during ascent).  If you want to point a finger at a particular time when it obviously made sense to put SM development on hold, that would be the moment to finger.

So where are they now?  It seems obvious they are well aware of the federal budget cycle.  We're expecting the President's proposal for FY13 in about a month, right?

[Patchouli]

We do indeed have better models, but hypersonics is much harder than typical subsonic CFD. Much more difficult to validate, too. The higher and faster you go, the further away from typical continuous supersonic CFD. You start having non-continuum effects and complicated dissociative chemistry and surface catalysis, etc.

That said, SpaceX had a successful reentry first try. I am confident NASA (or LM) could've done it quite successfully if another design had been chosen. People have given NASA grief about using an unnecessarily complex or high performance design for other projects, and this was a case where they could get a head start in development by having the shape already validated.

OT but probably a good excuse to resurrect the X34 just for a low cost platform to help out with this research.
A larger high speed wind tunnel or gun capable of different gas mixtures also would be nice too.

It seems after the failure of the X33 NASA just became afraid to try anything daring.

Now back on the SM it might make a lot of sense to combine many of it's systems with one of the CCDev vehicles vs maintaining production for a unique engine even if said engine has a lot of heritage.
A detuned RS-88 with a high expansion nozzle seems like a good candidate.

It's designed to be a LAS engine so it's designed to be as reliable as possible.

[manboy]

What kind of shape do you think they should have gone with?

IMHO, I personally like the Dreamchaser XL concept. I understand why they went with the Apollo shape (well known and in theory less risk) but I didn’t like the arbitrary way they just ruled all others out.

LM for instance originally offered a delta winged craft. Boeing offered an Apollo shape, but with a Soyuz like orbital module.

I think NASA locked itself in too early. It wanted to get underway asap, but planning is very important. I mean heck it took Apollo a year to go for lunar orbit rendezvous(perhaps more if you count pre Apollo planning).  The shuttle while not yet a project was in the planning phases since at least 1968. I think these options should have been evaluated further rather than the current choice.

But with a spaceplane you get stuck with a large exposed heatshield for those two year long missions.

I am a capsule guy, but I would like to think that the state of aerothermodynamics knowledge is advanced enough that a significantly more volume-efficient design (i.e. a biconic capsule or maybe something like the Dragon or Soyuz capsules) doesn't pose such a big hurdle that that initial ease in qualifying the design completely overwhelms the long-term benefits from the more efficient design. After all, Dragon reentered successfully on the first try, and it's not like SpaceX has a lot of money to burn on such analysis.

Me thinks it may be an example of something which is hard to quantify (i.e. the difficulty of qualifying a new shape) being over-weighted in the analysis. Suppose a 10% weight reduction were possible, though? That 10% would ripple through the whole stack, quite possibly saving billions.

That said, Orion is a sensible shape as well. I don't think I necessarily would've wanted to pick the less developed shape and risk slowing down the whole program by several years if it didn't pan out.

I was under the impression that the Soyuz and Dragon capsule designs are not as good at aerobraking as Orion/Apollo and experience higher Gs on re-entry.

[Patchouli]

But with a spaceplane you get stuck with a large exposed heatshield for those two year long missions.

That's probably the best argument for using a capsule for some missions though the side wall insulation is still exposed though generally it's low temp and more forgiving of damage.