DIRECT v3.0 - Thread 1

[engstudent]

great job on the illustrations and goodluck with the review pannel DIRECT.

also :: somebody should update http://en.wikipedia.org/wiki/DIRECT after all the details are up at the DIRECT site.

[Stephan]

Do you plan to use the RL-10B-2 with noozles already extended ? The skirt seems long enough to allow that.

[kraisee]

Do you plan to use the RL-10B-2 with noozles already extended ? The skirt seems long enough to allow that.

No.   The nozzle is not designed or qualified to fly in the extended position during first-stage flight.

You also want it retracted to provide maximum clearances when jettisoning the Core/Interstage.   Retracted, there is plenty of space around the engines, but extended the Interstage gets pretty close to the nozzles as it falls away.

Ross.

[renclod]

The Fwd Skirt actually comes in along with the 'foam' which covers the rest of the LOX tank.   Its just a visual thing.   They could be separated, but we wanted to keep the video short.

Ross.

Thanks, I knew I'd catch your attention !
But this is confusing... "comes in along with the 'foam' " ? What exactly comes in along ?
See, NASA Constellation's Ares I-X (yes, I know, anathema ! lol) has "a 14,000-pound forward skirt [] constructed entirely of the same kind of armored steel used on Abrams A-1 tanks and armored Humvees"

Jupiter's forward skirt is build of what ?

TIA again, (hope I'm not abusing your patience).

[mars.is.wet]

There are some that will say the RL-10's are not human rate-able without significant effort.  A number of internal and external studies have shown that.  Some of those studies come from the contractors.

Not saying who is right, but a simple assertion that it will work "off the shelf" will not stand up against the body of evidence I have seen, and weakens the credibility of the proposal. 

[mars.is.wet]

Also, what is a "Human Rated SSME" (meaning, is there a not-human-rated SSME) in the animation?  Made sense for RS-68, for SSME, not so much.

[Danny Dot]

snip
FYI:   A standard Jupiter-130 CLV heading for ISS has a GLOW of 2,057,232kg.   It lifts 66,980kg of useful payload to 100x100nmi, 51.6deg.   Assuming a 20,185kg Orion, that leaves 46,795kg for additional cargo -- roughly equivalent to 3 ISS-bound Shuttle payloads worth.

Ross.

This is a good selling point for Jupiter.  ISS upmass problems are solved with Jupiter.  It think upmass will turn out to be a huge problem in the post shuttle ISS ops.

Do you have a plan on what container to use for pressurized cargo and a ops concept for docking the container and Orion?  I am thinking Orion takes the container for a grapple, then it docks itself.

This may not work because it may not be possible to do Prox Ops with Orion with a big payload on its nose.  Having said this, the Russians may do something like this with their auto docking of the big modules.

Danny Deger

[TrueBlueWitt]

snip
FYI:   A standard Jupiter-130 CLV heading for ISS has a GLOW of 2,057,232kg.   It lifts 66,980kg of useful payload to 100x100nmi, 51.6deg.   Assuming a 20,185kg Orion, that leaves 46,795kg for additional cargo -- roughly equivalent to 3 ISS-bound Shuttle payloads worth.

Ross.

This is a good selling point for Jupiter.  ISS upmass problems are solved with Jupiter.  It think upmass will turn out to be a huge problem in the post shuttle ISS ops.

Do you have a plan on what container for use for pressurized cargo and a ops concept for docking the container and Orion?  I am thinking Orion takes the container for a grapple, then it docks itself.

Danny Deger

Would an ATV fit inside the Shroud? Could lift one basically "for free" if the case.  let it do it's own docking. 

Although long term, a seperate Pressure Shell for cargo would seem to be a better solution.

[gladiator1332]

Thanks for the updates Ross!

[Ben the Space Brit]

Although long term, a seperate Pressure Shell for cargo would seem to be a better solution.

FWIW, my favoured solution has always been an MPLM replacment with a modified hull so that it has a Soyuz RV-like shape.  Add a short-life RCS and a de-orbit retro pack and, voila! You have the Autonomous Return Station Logistics Module (ARSLM).  Carried into orbit on an Orion/SSPDM and returning autominously to splash down in the Gulf of Mexico after it has completed its mission.

I thought about making ARSLM have an untended launch capability but that would mean a lot of extra avionics and more work on the software.  A dumb-dumb remote triggered auto-descent system is sufficient for an Orion-tended launch profile.

With reference to the two renders of 'exploded' Jupiter LVs, I have to say that the touch I like is the two little human figures in the bottom left corner.  It emphasises just how much bigger than the Apollo the Orion is.

[gladiator1332]

Updated the facebook group with some of the Direct 3.0 images and video:

http://www.facebook.com/group.php?gid=45545713366

[Danny Dot]

The Fwd Skirt actually comes in along with the 'foam' which covers the rest of the LOX tank.   Its just a visual thing.   They could be separated, but we wanted to keep the video short.

Ross.

Do you still need the foam now that the orbiter is gone?  How much does the foam weigh?  I would think the SRBs can take the impact of shedding ice.  How about the Delta IV Heavy?  Does it shed a bunch of ice on itself on ascent?  I have seen some video of Saturn V launches and huge chucks of ice are coming off.

Danny Deger

[Jim]

Although long term, a seperate Pressure Shell for cargo would seem to be a better solution.

FWIW, my favoured solution has always been an MPLM replacment with a modified hull so that it has a Soyuz RV-like shape.  Add a short-life RCS and a de-orbit retro pack and, voila! You have the Autonomous Return Station Logistics Module (ARSLM).  Carried into orbit on an Orion/SSPDM and returning autominously to splash down in the Gulf of Mexico after it has completed its mission.

And what is it going to carry other than garbage?  If it can't come down like the shuttle, then it is useless for science or return hardware.  Access and loads are bad.

[Pheogh]

Two quick notes all.

These animations are primarily intended for a less sophisticated audience as a teaching tool. The engineering accuracy (hope you are all sitting down) is not the most important element. The primary purpose is to show how the SDLV transformation occurs. So as it relates to the forward skirt the most important "transitional" component here is to illustrate that we modify the ogive "tank top" to a "regular" top. For all intensive purpose to the lay person these are internal structures to the foam (which is visually what they know best) so we needed to show it removed and then replaced.

This philosophy carries through to the SSME's as well. I think we can all agree that a significant and commonly trumpeted issue is "what" and "what is not" man rated. So the use of "human rated" in the titling is simply a way of highlighting that the engines have in fact passed this gate.

I know there will be some holes and inconsistency's but in general the animation is simply trying to communicate a whole lot in a small amount of time.

Philip

[Jim]

Do you still need the foam now that the orbiter is gone?  How much does the foam weigh? 

1.  I would think the SRBs can take the impact of shedding ice. 

2.  How about the Delta IV Heavy?  Does it shed a bunch of ice on itself on ascent?  I have seen some video of Saturn V launches and huge chucks of ice are coming off.

Danny Deger

1.  No, the IEA's are vulnerable
2.  D-IV has foam on all tanks

[gladiator1332]

I also like the inclusion of the alternative Ares names for the Jupiter vehicles, Ares 3 and Ares 4. I think it really shows that Jupiter is willing to work with Ares and provide a smooth transition from Ares 1 / Ares 5 to Direct.

Whether it was intentionally done to allow NASA to save some face or not, they can certainly do so.

[MP99]

Copied from V2.0 thread, since it appears to be just as relevant to DIRECT 3.0...

And no, the LOX tank is sized to precisely the same capacity as the current ET's Ogive tank.

We do still have an option to increase the capacity of both the LOX and LH2 tanks by ~7-9% (in the same way as NLS was going to), but right now, mostly for simplicity sake, we have simply chosen not to mess around with altering the capacities.   We can close all performance requirements comfortably without it.

Not heard of that 7-9% stretch option before.

I'd suspect this is because the relationship of SRB-to-ET-to-Shuttle results in more space under the ET for engines than DIRECT actually needs?

Shrink the engine space and extend the H2 tank downwards?



It recently occured to me to wonder how there is space under the "ET" to fit a bunch of engines at all. Shuttle's ET is sized to fit between the SRB's (and presumably not to extend too far down into the base heating zone). Nothing about the shuttle "demands" that this should leave enough space under the ET for a set of engines.



That also raised another question. DIRECT's H2 tank height (bottom of barrel section to thrust beam) is defined by the distance between the lower & upper SRB attach points.

Adding another segment to the SRB also requires the same H2 barrel stretch. I'd always assumed this was a 25% increase in core fuel, but now that doesn't seem right.

How much does the core fuel load increase for the heavy config?

cheers, Martin

[Danny Dot]

Do you still need the foam now that the orbiter is gone?  How much does the foam weigh? 

1.  I would think the SRBs can take the impact of shedding ice. 

2.  How about the Delta IV Heavy?  Does it shed a bunch of ice on itself on ascent?  I have seen some video of Saturn V launches and huge chucks of ice are coming off.

Danny Deger

1.  No, the IEA's are vulnerable
2.  D-IV has foam on all tanks

Thanks for the info, but what are the IEA's.  If the Delta needs foam that is a sign Jupiter needs foam.

Danny Deger

[gladiator1332]

I noticed that the Jupiter-130 will have two engines closer to the front of the vehicle, and one closer to the back. Will this create an offset thrust situation or an offset weight situation? And if so how will this be counteracted?

Forgive me if this is a non-issue, as I am not too good with the rocket science side of these things.

[psloss]

Thanks for the info, but what are the IEA's.

SRB integrated electronics assembly on the ET attach ring.  One of them nearly took a hit from the ET bipod foam that came off on STS-112.  (Edit: the foam hit the left ET attach ring near the IEA.)