DIRECT v3.0 - Thread 1

[Danny Dot]

snip

If you'd ever worked engineering problems.. you'd realize metric really does simplify any analysis work.  snip

I have worked many engineering problems.  Imperial works great. 

My big problem is I think imperial.  My specialty is conceptual design, which lends itself well to engineering in one's head.  When I engineer in metric on a conceptual problem, I convert to imperial to think about it, design the system in my head, then convert to metric for my costumer.  I have tried and failed to think in metric, but it hasn't happened so far.

The only real problems is I think pounds mass, but calculate in slugs.  I almost always think in feet, so the conversion to inches is not that big of a deal.

Metric has a similar problem.  Many times it is better to think kilograms force, but you always calculate in Newtons.

Not to mention the changes to the infrastructure that are huge.

Danny Deger

[phantomdj]

I suggest that you take out the last paragraph, which has a negative focus.  Just focus on the positive with direct as a better solution.  You could also add comments about job loss impact from the gap.  It is a hot ticket with elected officials.

Agreed.  I'll change it to:

It’s time to embrace a vehicle that is less expensive, more versatile and faster to build.

[TrueBlueWitt]

snip

If you'd ever worked engineering problems.. you'd realize metric really does simplify any analysis work.  snip

I have worked many engineering problems.  Imperial works great. 

My big problem is I think imperial.  My specialty is conceptual design, which lends itself well to engineering in one's head.  When I engineer in metric on a conceptual problem, I convert to imperial to think about it, design the system in my head, then convert to metric for my costumer.  I have tried and failed to think in metric, but it hasn't happened so far.

The only real problems is I think pounds mass, but calculate in slugs.  I almost always think in feet, so the conversion to inches is not that big of a deal.

Metric has a similar problem.  Many times it is better to think kilograms force, but you always calculate in Newtons.

Not to mention the changes to the infrastructure that are huge.

Danny Deger

While in my personal life I still think completely in Imperial units.. I have always worked in Metric Units at work.. mm/T/s take a while to get used to I suppose.. A lot  like learning a second language..   

It would be great if every code would universally translate between units. Put them in in your preferred units.. even mixing and matching, and get them back out in the Units the customer wants.

I do realize it's not easy to switch. Although I would think transfer of information between NASA and the Science community has to be complicated at times by the Unit conversions.

[Danny Dot]

snip

A parafoil could be a lightweight route to sustain horizontal motion and unlike X-38, after a few miles of travel it could be discarded in favor of traditional parachutes.

I am not sure I follow completely.  Is the idea to use a high temp parafoil to get away from the SRB debris?  If yes, why not just make a round chute out of the same stuff. 

Anyway, this would certainly be a bigger impact to Orion than adding a sustainer motor to the LAS.  Parafoils have to be controlled and guided.  You don't just open them.  Remember Orion is close to PDR.  Changes to it must be kept to a minimum. 

The X-38 parafoil idea was a huge mistake in my opinion.  Way to much work for too little gain.  While observing the program from the outside, I thought all the work might be worth it because almost any open field or airport in the world would become an landing site.  This would be really nice for the ACRV mission.   Later I found out because it shedded stuff like the chute covers up high, it basically needed the same size clear area as a round would have.  The program gained almost nothing to go to a parafoil.  To me it was just another NASA big ego running out of control to make his pet project.

[Danny Dot]

snip

I've seen him use it, but don't feel like hunting down the post. The true victory will be when he can properly use "all y'all".

In my part of Texas "all y'all" is not used much.  It is gramatically incorect.  Y'all is second person plural and I must use it to converse clearly.

I heard "all y'all" in Georgia and North Carolina.  Mostly by women trying to be sound cute.  The same type that like to call total strangers "Sugar".

Danny Deger

[kraisee]

Is plume impingement an issue for DIRECT as well?

Jesse, it exists on Jupiter, just like on Shuttle, but the design has been done in order to explicity work in that environment.

So, plume impingement still exists, but it is not a 'problem' on this vehicle.

Ross

Is this in reference to the base heating near the SSME? Or the LAS motors tearing into the ET during abort sequence? Danny's comment about plume impingement was preceded by a discussion pertaining to NSC's potential "show-stopper."

Sorry if I've over-complicated this!

Jesse

Sorry, didn't realize the context (I was using my iTouch at the time, and I didn't read the previous page of comments).

I was referring to Plume Impingement at the Base of the vehicle.

For confirmation:   There are no concerns about the LAS impinging on the vehicle below the Orion in the case of any aborts.

Ross.

[Bill White]

I see the objective as gaining the ability to move Orion laterally and thereby increase distance from the debris field or debris cloud - aren't we talking about falling bits of very hot solid propellant falling towards Earth from the exploded SRB?

How far would Orion need to move - laterally - to avoid coming down within and through the SRB debris cloud? One mile? (1.6 kilometers) Five miles? (8 kilometers) Ten miles? (16 kilometers)

Then all your sustainer motor needs to do is add sufficient altitude to allow the parafoil to achieve that lateral separation then the parafoil can be cut loose and the primary parachutes opened (the same ones Orion would use after a successful mission).

Thus the parafoil need only survive the heat long enough to get Orion that lateral separation rather than survive coming down through the debris.

= = =

Or, am I visualizing this wrong?

[Danny Dot]

I see the objective as gaining the ability to move Orion laterally and thereby increase distance from the debris field or debris cloud - aren't we talking about falling bits of very hot solid propellant falling towards Earth from the exploded SRB?

How far would Orion need to move - laterally - to avoid coming down within and through the SRB debris cloud? One mile? (1.6 kilometers) Five miles? (8 kilometers) Ten miles? (16 kilometers)

Then all your sustainer motor needs to do is add sufficient altitude to allow the parafoil to achieve that lateral separation then the parafoil can be cut loose and the primary parachutes opened (the same ones Orion would use after a successful mission).

Thus the parafoil need only survive the heat long enough to get Orion that lateral separation rather than survive coming down through the debris.

= = =

Or, am I visualizing this wrong?

Again, not 100% sure I capture your idea.  But if one could build a parafoil to survive a debris field, it could probably fly out of the debris field to let the rounds open in the clear.  The Air Force stated the debris field was about 8000 foot radius. 

I don't think that is going to happen.  This is not radiant heat from a liquid fireball.  It is huge chunks of high density propellant burning at 4000 degrees.

[Bill White]

Can the LAS motor achieve an 8000 foot separation above the debris cloud?

If a sustainer motor can do that, perhaps a parafoil can give 8000 feet of lateral separation as Orion comes down.

Edit to add: Combine Ross's "up" idea with a lateral capability so you don't need to go "up" quite as far -- just up enough to let the parafoil glide you clear.

And, the X-38 parafoils would seem far more capable than what is needed to achieve 8000 feet of lateral separation before opening the primary round parachutes.

[kraisee]

to be noted, that Depots and PT is not in the baseline of Direct, but is on the wish list for Future Vision, but does feed into Direct's capabilities and strong points...

I'd just like to clarify that Propellant Depot's actually ARE on our baseline -- but they are for Phase 3 of our plans, not Phase 2.   Let me explain:-

Phase 1:   Close the Gap
Beginning Around:   2013

- Jupiter-130 to ISS, 20mT Orion + 40mT Payload

- Jupiter-130 for Hubble Servicing

- Jupiter-130 + Delta Heavy Cryogenic Upper Stage for "Apollo 8"-style mission

- Jupiter-130 (with or without DHCUS) available for large ~75mT IMLEO Science Missions


Phase 2: Initial Lunar Exploration
Beginning Around:   2018

- Jupiter-24x Dual-Launch Lunar Mission, No Propellant Transfer, ~80mT thru TLI

- Jupiter-24x Dual-Launch NEO Mission, No Propellant Transfer, Performance TBD

- Jupiter-24x Three-Launch Phobos Mission, No Propellant Transfer, Performance TBD

- Jupiter-130 (with or without DHCUS) available for large ~75mT IMLEO Science Missions

- Jupiter-24x available for very large ~100mT IMLEO Science Missions

NOTE:   Lunar mission hardware is actually designed with Mars in mind


Phase 3: Advanced Exploration
Beginning Around:   2022

- Jupiter-24x Single-Launch Lunar Missions, EDS (and LSAM?) would be re-fueled in LEO from a commercially supplied Depot, payloads greater than 100mT are possible thru TLI

- Jupiter-24x Single-Launch NEO Missions, EDS would be re-fueled in LEO from a commercially supplied Depot, payloads greater than 100mT are possible.

- Jupiter-24x Dual-Launch Phobos Missions, EDS would be re-fueled in LEO from a commercially supplied Depot, payloads greater than 200mT are possible.

- Jupiter-24x Dual-Launch Mars Missions, EDS and Lander launched dry and both are fueled in LEO using Depot supplied by both commercial suppliers and international partners.   IMLEO would be in the ~1,000mT class.

- Jupiter-24x Jovian Missions using Depot located either in LEO or at EML-2, depending upon the availability of Lunar ISRU.   Exact mission profile TBD.   IMLEO TBD.

- Jupiter-130 (with or without DHCUS) available for large ~75mT IMLEO Science Missions

- Jupiter-24x available for very large ~100mT IMLEO Science Missions

- Jupiter + Depot available for extremely large >200mT IMLEO Science Missions


Phase 2 is primarily designed as a 'stepping stone' to get from ISS to the full architecture, instead of trying to make a single "giant leap" straight from LEO to the full capability architecture.

Phase 2 'could' be skipped, bt we think that from both a technological risk, from a cost/schedule risk and from an overall Programmatic risk stand-point, it is a better approach to include it as a 'stepping stone'.

Ross.

[Danny Dot]

Can the LAS motor achieve an 8000 foot separation above the debris cloud?

If a sustainer motor can do that, perhaps a parafoil can give 8000 feet of lateral separation as Orion comes down.

Edit to add: Combine Ross's "up" idea with a lateral capability so you don't need to go "up" quite as far -- just up enough to let the parafoil glide you clear.

And, the X-38 parafoils would seem far more capable than what is needed to achieve 8000 feet of lateral separation before opening the primary round parachutes.

Do you have Excel?  If you do, it is easy to run it at home.  I am a bit busy to run your problem right now, but many someone else can do your run for you.

Danny Deger

[Lobo]

Well, then let's convert to metric once and for all. The rest of the world has already done so...

No, they didn't. At least not all of them. There are actually 3 countries that are still hapily using imperial system. Burma, Liberia and... well, United States. Source: http://en.wikipedia.org/wiki/Metrication#Overview.

It’s a little more involved than just that.
Many countries use a mix of units, or at least hold on to some old conventions.  In England they still often give their weights in “stones”, but is different even than what we use in the US which is “US Standard” (which is similar but different than the British system of “Imperial”.)
In Australia, when measuring lumber, they still use “board-feet”.  So there are still some hold out conventions.

Common standards and measures are actually one of the greatest engineering inventions of the 20th Century (among the ASME top 10 inventions) because of how it broadly expanded commonality in design.  Prior to that, a “foot” could vary country to country.

That being said, I had a strength of materials professor in college who hated the SI system (interestingly enough “metric” and “SI” aren’t exactly the same thing.  SI doesn’t use all metric terms.  You won’t ever see a “hectometer” or a “centigram” in SI, etc)
He hated it because he said there was very little “intuitiveness” to it.  You can visualize what a “pound” or a “foot” is.  Mentally you can imagine a “pound per square inch”.  You know right off the top of your head about what a 1000 pounds is like, or 1000 miles.  We know immediate how much a gallon or 100 gallons is.  Or what 1 atmosphere feels like.
But, what does a Newton feel like?  What does a Pascal feel like?  What does 500 kg feel like?  (can you imagine without doing the conversion to pounds in your head?  Probably not).  Ditto for 1000 km. 
How much is 100 cubic meters?  But you know about what 100 gallons is, so it’s easier to mentially check your work.  If you are calculating the size of a hot tub you are building, and you come up with 5000 gallons, then you know you probably made a calculation error somewhere.  But if you come up with 18.9 cubic meters…did you make a mistake?  Yes, you did, but you have no intuitive feel for it.
We know intuitively we can live in 1 or 2 atmospheres.  And that 30 atmosphere will kill us.  But will 101,000 Pascals kill you?  How about 100 Pascals?  Or a million Pascals?  Do you –know- right away without doing a conversion?

If you have a 2010 Ford Mustang Shelby 500 GT, how many kilowatts of power does it produce?  You know how much 500 HP is, intuitively…but kW? *shrug*

Obviously the more we’d deal with things like kg and km’s, the more we’d get an intuitive feel for them.  But does anyone even in Europe who’s been using metric for some time now have a good feel for a cubic meter of water or a pascal of pressure or a Newton of force?  I think not really.

Just thought it was an interesting view.  Probably cure more headaches than it’d cause to adopt SI units here in the US, don’t get me wrong.  But the people the quickest to advocate that I don’t think really understand the flip side to it.

[kraisee]

Well, then let's convert to metric once and for all. The rest of the world has already done so...

No, they didn't. At least not all of them. There are actually 3 countries that are still hapily using imperial system. Burma, Liberia and... well, United States. Source: http://en.wikipedia.org/wiki/Metrication#Overview.

Those technical "giants" Liberia and Burma...   I do not think they represent the best justification for sticking with the old system!

Heck, even the country from which the "Imperial" name comes from changed over before I went to school...

Ross.

[tamarack]

Suppose Orion's abort trajectory added both additional altitude and lateral momentum prior to a parafoil being deployed.
 ...
A parafoil could be a lightweight route to sustain horizontal motion and unlike X-38, after a few miles of travel it could be discarded in favor of traditional parachutes.

Good chance a parafoil would take too long to deploy.

How much can we stall and flatten the debris cloud to give Orion room? ie: A downward shape-charge between the liquid tanks detonated just after Orion aborts. If it's going to blow, may as well use that force to our advantage.

[brihath]

snip
We discussed this at dinner following the Hearing and that is what Ross was saying too.  I think there was a consensus among all of us there that a sustainer is needed.  Fortunately, Direct is one of the options that has the margin to accomodate this, but it would add development time to Orion's schedule.  The estimate discussed was at least 12 months.

Y'all need to get with the Orion folks and find out if LAS is the long pole in the tent.  My guess is the software updates needed are worse than the hardware design issues.  You might ask if they could go back to unguided sense you don't fly at the insane dynamic pressure of the death trap Direct is going to replace.

If Sally Ride is correct the more realistic date for Orion is 2017, and adding a sustainer is 12 months, General Bolden will not like that much.

Danny Deger

Has Ross learned to say y'all yet?

Why?  Is he from southern England?

LOL- Just kidding, Ross....I like your "drawl"! ;-)

[Mark S]

Just thought it was an interesting view.  Probably cure more headaches than it’d cause to adopt SI units here in the US, don’t get me wrong.  But the people the quickest to advocate that I don’t think really understand the flip side to it.

You can make it sound as complicated as possible, if that's what you want to stick with.  But if you really want to convert, the way to do it is to make it a policy that all "new" stuff gets done in Metric, and only "legacy" stuff is maintained in Imperial units.  I can guarantee you that if this approach was taken (and enforced), then pretty soon 90% of everything would be in Metric.

And for old farts (like me) who can't adapt, well, get used to doing conversions in your head.

We've been converting to Metric since I was in grade school.  Let's get it over with!

Mark S.

[phantomdj]

Ross,

Over the last 3 public meetings Ares I/V got about 5 hours of "free" advertising but no mention of alternative vehicles (i.e. Direct) and their capabilities.  Where was your rebuttal or 2 hours sales pitch?

[Lobo]

Ross,

Quick question that's probably been answered before.  From a manufacturing standpoint, is there any difference between the J-130 and J-24x cores?  Meaning, at Michoud would they just roll the exact some core off the assembly line, then at the VAB they put it together with the engine and upperstage config they want?
Or are there actually core differences between the two that would be manufactured a bit different at Michoud.?

[phantomdj]

To add to Lobo's question, is the core strength the same whether it's just a 130 payload or a 24x 2nd stage and payload? Does it have to be reinforced?

[Arthur]

I say scrap the LAS, scrap the melting parachutes, scrap the sustainer motor. Use the weight savings to add reactive armor to the Orion and plow through the debris to escape to LEO. Then launch a rescue mission from the ISS. That’s how John Wayne would handle it.

[just kidding]