DIRECT v3.0 - Thread 1

[MP99]

But Jupiter-24x is not the element which will determine the Lunar Landing -- Altair is the critical piece who's schedule will drive the date of the first mission.   Anyone who think Altair will take less than 8 years to develop from now, is smoking something pretty strong and I guarantee that even that schedule will slip if NASA budget continues to be squeezed by the White House and Congress any further.

So, IMHO, even if we got the green light TODAY, it would be extremely difficult to make a 2017 Lunar mission return date and I would suggest 2018 is more realistic at this point.

But if the green light isn't given for another 6 months, that schedule will slip by the same amount -- guaranteed.   And while I'd love government to be fast and efficient in making such decisions, I don't think anyone believes this is going to magically happen the day the Augustine Committee reports (end of August).

Ross,

NASA are currently working on Altair, and they seem to be continuing with their projects whilst Augustine deliberates. Presumably they may then do the same until (if) WH/congress issue new orders.

Are they still working on Altair? How much will things be delayed if NASA keeps to the current (since Augustine was announced) course?

cheers, Martin

[fotoguzzi]

I haven't even started to model the effect of radiant heat from the field. 

(Purposefully using layman's terms, and I haven't read all the posts yet; sorry):  If you have the volume of the sphere / hemisphere (well, column, may be the most accurate as the debris descends) and the mass of solid fuel remaining at 20 -50 sec, could you get a zeroth-order approximation of air temperature?

Kind of like, how much firewood would it take to warm up the Astrodome.

Modiify: fudge quotes, add column

[ugordan]

Falcon 9 Boosters might make some sense especially once(if) SpaceX developes their BFE(Big Falcon Engine)..

With or without the BFE, you couldn't just use a F9 first stage as a booster just as you couldn't attach it to an ET easily. The structural loads on the F9 stage weren't designed to be compatible with the way SRBs transfer loads to the ET interstage crossbeam. F9 stages probably act like EELV solids transfer loads to the core - at the thrust structure level. Would only make sense seeing as F9 was meant to have 2 strapons like EELVs do.

[deltaV]

High temp fabrics might be an option if close to a fireball.  There are less exotic ones than the one you mentioned.  Most increased mass and volume.  Not a good thing to do to poor little Orion at this point.  Remember it is close to PDR and the gap is growing.

Rather than replacing Orion's main drogue, which needs to be very light to travel to the moon and back, how about a separate drogue that's jettisoned with the LAS? Might making a new drogue also reduce the effects on other parts of Orion's design?

[TrueBlueWitt]

Falcon 9 Boosters might make some sense especially once(if) SpaceX developes their BFE(Big Falcon Engine)..

With or without the BFE, you couldn't just use a F9 first stage as a booster just as you couldn't attach it to an ET easily. The structural loads on the F9 stage weren't designed to be compatible with the way SRBs transfer loads to the ET interstage crossbeam. F9 stages probably act like EELV solids transfer loads to the core - at the thrust structure level. Would only make sense seeing as F9 was meant to have 2 strapons like EELVs do.

True enough.. and many other issues(supporting Massive Core on MLP)

I think we're just pining for a Kerolox replacement for the SSRMs..  Eliminate a lot of abort issues.

[strangequark]

True enough.. and many other issues(supporting Massive Core on MLP)

I think we're just pining for a Kerolox replacement for the SSRMs..  Eliminate a lot of abort issues.

I'd personally prefer those issues be used as an excuse to mature large hybrid technology. There's a lot of exciting stuff recently that indicates the regression rate problems are easily surmountable. Once you have that problem licked, they're a better choice as boosters for manned systems, IMHO. Keep ATK in the game as well, from the political side, as you're still casting large rubber composite grains, and the liquid side of it need not be terribly complex. Be interesting to see if one could develop something that's a "drop-in" replacement for the RSRMs.

[ar-phanad]

High temp fabrics might be an option if close to a fireball.  There are less exotic ones than the one you mentioned.  Most increased mass and volume.  Not a good thing to do to poor little Orion at this point.  Remember it is close to PDR and the gap is growing.

Rather than replacing Orion's main drogue, which needs to be very light to travel to the moon and back, how about a separate drogue that's jettisoned with the LAS? Might making a new drogue also reduce the effects on other parts of Orion's design?

Cool idea. Where would you fit it, I wonder? You might have a multi-stage LAS...

Jesse

[Ronsmytheiii]

Rather than replacing Orion's main drogue, which needs to be very light to travel to the moon and back, how about a separate drogue that's jettisoned with the LAS? Might making a new drogue also reduce the effects on other parts of Orion's design?

Or you could simply launch now with the heavier chutes for ISS, then upgrade the LAS for Moon mission

[ar-phanad]

Rather than replacing Orion's main drogue, which needs to be very light to travel to the moon and back, how about a separate drogue that's jettisoned with the LAS? Might making a new drogue also reduce the effects on other parts of Orion's design?

Or you could simply launch now with the heavier chutes for ISS, then upgrade the LAS for Moon mission

Maybe by that point adding a sustainer engine to the LAS wouldn't be causing any serious delays?

Jesse

[clongton]

Be interesting to see if one could develop something that's a "drop-in" replacement for the RSRMs.

Interestingly enough, SpaceX has licensed the technology that was supposed to build the RS-84 kero-lox engines. I wonder what a SpaceX core that sported a pair of the BFR engines each would look like on either side of a Jupiter core (that's 4xF1-class kerolox engines total)?

[fotoguzzi]

Re: exploding solid stages:  Others and I have been bugging Danny about blowing the nozzle off the end of the SRB.  Is that idea DOA?  Would it take longer to make a two-part destruct than to put an upsidedown RSRM on top of Orion (the natural result if current trends continue)?

[strangequark]

Re: exploding solid stages:  Others and I have been bugging Danny about blowing the nozzle off the end of the SRB.  Is that idea DOA?  Would it take longer to make a two-part destruct than to put an upsidedown RSRM on top of Orion (the natural result if current trends continue)?

Blowing the aft exit cone extension (I assume that's what you're talking about) will do nothing to depressurize the RSRM, since the LSC is downstream of the nozzle throat. You'll reduce thrust, but not even come close to eliminating it.

[Lobo]

I have much hope for LRBs as an eventual upgrade to DIRECT or NSC. Would need development of a new engine though, since that is would re-building the F-1 would be analogous to anyway. Why does everyone like the idea of resurrecting  it so much anyway? I seem to see similar ideas a lot.

Agreed.  I think people like the F-1 because I think it was the most powerful kerolox engine ever made in the US, on the most powerful HLV ever flown.  “More power! More power!  *grunt* *grunt*.
They were producing muscle cars in the 60’s producing 400-500 HP with 450+ CI blocks too, which more more than most current “muscle” cars.  But they got 8 miles to the gallon and only ran for 100K miles if you were lucky before needing a full rebuild.  Today a car with an engine around 250 CI can produce 300 HP and be in a car that’s faster off the line, faster in the quarter, and faster top speed than the old muscle cars.
Sure, it’s not as –powerful- as the old Novas, Chavell’s, Fairlanes, Suber Bee’s or Chargers, but they’ll run for 200K miles, get over 20 MPG, and perform similar.
They don’t have the same HP as the old big blocks, but they’ll outrun and outlast the.

That’s the F-1 I think, and people are drawn to it like they are the old Muscle Cars.  We –could- build the old big blocks and old muscle cars today, but we don’t.  We build better and more reliable, higher performance,  and efficient cars.  But people still like to say they have the “biggest” or “most powerful”.

But the old F-1 was inefficient and very expensive from what I understand, part of the reason the Saturn V was powerful, but hugely expensive, and ultimately cancelled.
Today, instead of a 3-stage rocket, we have one or two stages with reusable boosters.  Kerolox boosters would be great for several reasons.  Today we should either start producing US made RD-180’s and use them in clusters, or develop a US equivalent of the Russian RD-170.  The RD-170 has about 200,000 lb more thrust than the old F-1 and is more efficient.  And I assume if the Ruskies are producing it, which they are, it’s not all that expensive to build.  (As much as I hate to admit it, the Russians are usually great examples of doing more with far less).  We can buy some RD-170’s and make our own versions easy enough, we don’t need to even reinvent the wheel.  PWR can build the RD-180’s if they want, but it’s cheaper to buy them from the Russians for the Atlas V.  Politics being what they are apparently it’s a big no-no for NASA to be launching US astronauts on Russian made engines.
But PWR can make US made RD-180’s if there was the political will and money to do it.  The designs are done, we just need to tool up a plant and start pumping them out as I understand.

So, if we want –bigger-, don’t dust off the Old F-1, make a US version of the RD-170 (1.75 million lb thrust opposed to the F-1’s 1.5 million lb thrust at sea level).  Or easier yet, start making US versions of the RD-180 so NASA can start using them (860K lbs thrust sea level) and use them in pairs or clusters of 3 on LRB’s.  The RD-180 is sorta an RD-170 cut in half away.  But you’d need at least 3 RD-180’s to come close to replacing one SRB.  2 RD-170’s would get you a little more performance than the SRB, so that might be a better way.  Unless you go to a 4 booster design like Energia.  But now you are pretty radically changing the layout of the core.  And it’s hard to say if you’d be spending more to try to refurbish the LRB’s because of the damage the water would do to the LRB vs. the more simple SRB.  I don’t know what those numbers would be.   The engines might have to be disposed of entirely after each mission.
And how big would those boosters be?  Your LV might look more like a D4H with 3 8.4m cylinders rather than the large central cylinder with two smaller SRB’s.

[Lobo]

Lobo and phantomdj;
The Jupiter-130 core *IS* the Jupiter-24X core. We did not design the Jupiter-130, but actually designed the Jupiter-24X. All the Jupiter-130 really is, is an incomplete Jupiter-24X. It is missing the upper stage and the 4th SSME. It is not a separate launch vehicle per se; rather it is just a "flight configuration" of the Jupiter launch vehicle. It is not optimized in any way and therefore flies with less performance than it could have if it were optimized. But its performance anyway is more than "good enough" and the benefit is that there is no core difference between the 2 flight configurations of the 130 and the 24X.

Ok, that was my question.  So when they leave Michoud, they'll look all the same and they guys putting them on the barge will have no clue if it's going to fly in J-130 configuration or J-24x?

Just curious.  If so, that's good.  Always cheaper to make more of one widget than less each of 2 different widgets...even if they are "similar" widgets.

[kch]

Re: exploding solid stages:  Others and I have been bugging Danny about blowing the nozzle off the end of the SRB.  Is that idea DOA?  Would it take longer to make a two-part destruct than to put an upsidedown RSRM on top of Orion (the natural result if current trends continue)?

Blowing the aft exit cone extension (I assume that's what you're talking about) will do nothing to depressurize the RSRM, since the LSC is downstream of the nozzle throat. You'll reduce thrust, but not even come close to eliminating it.

I've had the impression that they actually meant blowing the entire nozzle off (including the throat, of course), which would do a much better job of uncorking the beastie ...

[strangequark]

I've had the impression that they actually meant blowing the entire nozzle off (including the throat, of course), which would do a much better job of uncorking the beastie ...

I suspect that would make matters worse, to be honest. The SRM nozzle is a partially submerged design. I would wager that, unless you're planning on severing the case, you'd have a good chance of plugging the whole thing...until it ruptured that is.

[kraisee]

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?

Bill, you might want to go watch Danny's video's on YouTube.   They explain the issue pretty well.



and





There are a lot of complexities though.   First, you need to work out how quickly the SRB's blow compared to when the LAS fires -- it makes a BIG difference.   Second, you also need to work out the angle which the SRB's are firing compared to the LAS trajectory -- if the vehicle breaks up, they could be at a completely unexpected angle, as much as 90 degrees up or down from the angle of the 'mother' vehicle!   And third, you need to re-calculate across a wide range of trajectory times, with most of the problems around T+30 thru T+60 seconds or so.

It is a *VERY* difficult problem.

Ross.

[kraisee]

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?

I have asked precisely the same question myself.

Ross.

[kch]

I've had the impression that they actually meant blowing the entire nozzle off (including the throat, of course), which would do a much better job of uncorking the beastie ...

I suspect that would make matters worse, to be honest. The SRM nozzle is a partially submerged design. I would wager that, unless you're planning on severing the case, you'd have a good chance of plugging the whole thing...until it ruptured that is.

That is the only way you'd get rid of the entire nozzle, isn't it?

[kraisee]

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.?

The Cores would all be exactly the same as shipped from MAF.

Where the engines would be fitted is open to debate still.   There are good arguments for integrating them at MAF prior to transport, but if that work was done at KSC then it would offer one additional means for saving some of the Shuttle jobs there.   The debate goes on, but both options are viable.

Ross.