DIRECT v3.0 - Thread 1

[zapkitty]

... It would be a good, forward-thinking idea to build the core in a way that the SRBs can be replaced without having to re-engineer the entire vehicle.

... The structure will certainly be strong enough to support itself. ... Also, if you design things for 'hypothetical' situations which might or might-not happen in the future...

You build your hydrolox and/or flyback boosters to plug'n'play where the SRBs go. (hah! take that you apostrophes!)

A combination of support from the mobile pad routed via swing arms through/around the boosters through the former SRB attach points.

In other words design any new boosters around the problem and leave Jupiter untouched.

Edit: trim, trim, trim

[Mark S]

Wasn’t one of the CxP programs primary objections to Direct 1.0 your initial proposal to transfer propellant between upper stages?  I thought they considered this an unacceptable risk and continued to hammer at it and criticize DIRECT for the maneuver long after it was removed from DIRECTs baseline mission profile.  If they are adopting this option after publically calling it dangerously unacceptable the directors at CxP must really be desperate.

John

Yeah, what he said.

Plus, if NASA puts fuel transfer back on the table, how much would that benefit DIRECT?  Could the JUS on the J-246 that is used to launch the CEV and LSAM be fully fueled instead of partially fueled?  Or would that make it too heavy?  If possible, how much fuel would be left over once the JUS+CEV+LSAM reaches LEO?  Any leftovers could be transferred to the EDS, which should be about half empty after making it to orbit.

How much mass could a fully fueled JUS/EDS place in LLO, assuming it did both TLI and LOI burns?

Mark S.

[DigitalMan]

....snip....

Looks like the same old, same old bullsh*t all over again.   What ever happened to quality leadership in this country?

Ross.

This seems like a good time for a Jack Bauer thought of the day. 

According to Jack, good people wind up corrupt by starting to lie about something small, before you know it you've gone bad.

[kraisee]

Wasn’t one of the CxP programs primary objections to Direct 1.0 your initial proposal to transfer propellant between upper stages?  I thought they considered this an unacceptable risk and continued to hammer at it and criticize DIRECT for the maneuver long after it was removed from DIRECTs baseline mission profile.  If they are adopting this option after publically calling it dangerously unacceptable the directors at CxP must really be desperate.

My thoughts precisely.

Seems the "Anything But DIRECT" attitude is now more important to them than getting the mission done properly.

What they don't seem to realize is that we aren't the enemy.   We've never been the enemy.   In fact, most of the people working on DIRECT are actually internal to the Ares program!   "They" are actually part of "us".

They could grab this ball from us and win this game so very, very easily if they only chose to.   We aren't interested in embarrassing them, we aren't interested in gaining a reputation or reveling in any "glory".   We just want a program which can really work while also being affordable.

Isn't that what all of us really want?   So *WHY* are some people so determined to keep this flippin' war going even one single day longer?   Can't we just put it all behind us and move forward as one united front?

The only other option is a very embarrassing "we had to remove the current Constellation Program Leadership", which really doesn't help anyone -- least of all NASA's reputation.

I hope that Cook, Cooke, Hanley & co. all realize that the axe has already been polished up and the axeman is already swinging it towards their necks.   They have very little time and they have run out of choices.   So why not try something truly desperate?   Why not take a serious look at DIRECT.   What is there to lose at this point?   If they ever tried to give it a fair look, I think they would actually agree that it really does have a good chance of working.   We have, for more than three years, been trying to persuade them to take this NASA-inspired idea* from us and make it their own!   Please!

It will truly make my day to be able to retire from this effort on the day I am convinced NASA is finally on a workable, affordable and sustainable path.   I'm looking forward to that day -- and I think it's only weeks away now.

* NOTE:   This is essentially NASA's own National Launch System idea anyway -- they already "own" it!

Also, didn’t you say in the past using an LOR mission profile would reduce payload by 20 percent.  I am starting to get very conspiratorial in my thinking, but it seems like using an underperforming LOR mission is the only way they can still justify building a big 10m core rocket to accomplish a 2-launch mission, and that Griffin’s ghost is still running the show over at CxP constantly saying, “No make it big, it has to be bigger than the Saturn V or else  …”

It really does seem to be the only explanation for this continued path.   I've tried and tried to come up with a better explanation, and I've asked so many people close to Griffin & co.   But nothing else holds any water any more...

"Must be bigger than von Braun did" and "Anything But DIRECT" seem to be the current mantra's at that level.   I just don't understand it.

Ross.

[kraisee]

Wasn’t one of the CxP programs primary objections to Direct 1.0 your initial proposal to transfer propellant between upper stages?  I thought they considered this an unacceptable risk and continued to hammer at it and criticize DIRECT for the maneuver long after it was removed from DIRECTs baseline mission profile.  If they are adopting this option after publically calling it dangerously unacceptable the directors at CxP must really be desperate.

John

Yeah, what he said.

Plus, if NASA puts fuel transfer back on the table, how much would that benefit DIRECT?  Could the JUS on the J-246 that is used to launch the CEV and LSAM be fully fueled instead of partially fueled?  Or would that make it too heavy?  If possible, how much fuel would be left over once the JUS+CEV+LSAM reaches LEO?  Any leftovers could be transferred to the EDS, which should be about half empty after making it to orbit.

How much mass could a fully fueled JUS/EDS place in LLO, assuming it did both TLI and LOI burns?

Mark S.

The CLV flight could, potentially, bring up anywhere up to 26,000kg of additional mass.

I haven't got time to do any precise calculations, but if there were some propellant transfer capabilities, that sort of extra mass allocation would sure as hell improve the performance of a system which already closes with comfortable margins!

Quick back-of-the-envelope calculations would seem to suggest it could produce anything up to about 10 metric ton improvement in payload performance thru TLI.   And that's assuming the PT equipment itself, plus transfer losses, accounted for 6,000kg -- which is a *very* generous estimate.

But I still wouldn't recommend it for the earliest missions.   K.I.S.S.   The first missions will be difficult enough even if we simplify them as much as possible.   We should find our feet first and then work to improve the systems.

Ross.

[Lab Lemming]

BUMP!
Another technical question that got buried by the FUD talk...

given the large PLF's that you have for the J130, have y'all considered launching the crewed J130 with a longer fairing so that the height of the capsule on the pad was the same as for the J246?  This would allow more commonality for tower access, etc.

(edit)
It would also buy you a few tenths of a second in case of a catastrophic failure.
(end edit)

That's excellent! There's your 3 minute direct presentation! Very clear about what's being done.

Excellent indeed, but one last suggestion...

... and I don't know if it will work, my vision is twisted and blurred at its best and I haven't seen a straight line in over a decade...

... as in the attached, but have the two cores rotated just enough to show the 3 SSME - 4 SSME difference. If that works at a usable scale (I did this at 1600% ) then you'll have covered all the bases...

I like this iteration best. Punctuation says eliminate the apostrophes after the acronyms. That aside, do we have permission to use this or a similar derivative for Wiki?

I'm concerned that the second Core Stage implies a second development effort -- which is not the case.   Remove it and this will be good to go.

Ross.

[MP99]

Hi,

Without seeing a picture - I am confused why there is a risk of regarding the EDS attachment mainly because as I am having difficulty seeing  how the EDS - Altair - Orion will stack together.

This diagram is on the directlauncher website:-

http://www.launchcomplexmodels.com/Direct/Pics/DIRECT_Lunar_Mission_Model_3.jpg

It's a hangover from DIRECT 1.0, but I believe it's pretty close to the current plan (although this shows Altair + Orion launching on a J-130, when it would now launch on a J-24x). Also, launch is currently planned to 130x130nmi, instead of 160x160.

cheers, Martin

last time I checked Orion does not dock to altair first, instead they ride "Eyeballs out" the Orion/Altair combination stays inline, separates from the second stage, then docks the end opposite of Orion to the EDS

Thanks for the link however the picture shows a combined launch of the Altair and Orion so does not answer my question because I thought the aim was for a duel Jupiter launch to spread the load.


Hence if you spread the load,

1. why wouldnt you beef up the Orions service module and remove the EDS function from Altair

2. or in a case of a one way Altair cargo launch, why not move the EDS function from Altair to a separate Service Module docked like orion would.

Hmmm .. might have a crack at making my own pick to explain myself better.
 
cheers

Simply, for the cargo-only mission, just leave the Orion off the mission. The rest is basically just the same.

Orion's SM is massively undersized to perform TLI, the EDS has it's own separate launch just to carry enough fuel to perform the job. SM uses less efficient fuel, so would have to be even bigger.

cheers, Martin

[guru]

Can someone tell me what FUD means?

Danny Deger

It means fear, uncertainty, and doubt.

[Steven Pietrobon]

Of course, for Cargo-only flights, the PLF is disposed of normally during ascent, as soon as aerodynamic heating drops to 0.1BTU/sec/sq ft -- which is typically around 70-75nmi altitude.

Or in metric, 1136 W/m² at 130-139 km (about the same as the Sun's radiation).

[Steven Pietrobon]

I have just been told to prepare for a new round of FUD from CxP regarding our Altair > EDS docking arrangement.

Calling Dr. Pietrobon!  Dr. Pietrobon to the launchpad - Stat!

I have given this some thought, but Buzz Aldrin is your man. He did his PhD on rendezvous.

My thinking is that there would be four attachment points, with cameras at each point on Altair looking at their respective attachment points on the EDS. A monitor in Orion would show each camera view in a quadrant. Using various distance measuring devices and watching the monitor the astronauts (or automated software) can slowly guide the Orion/Altair stack into dock with the EDS. Using optics, redundant cameras can be at each point, with a redundant monitor in Orion.

[Fletch]

    Of course, for Cargo-only flights, the PLF is disposed of normally during ascent, as soon as aerodynamic heating drops to 0.1BTU/sec/sq ft -- which is typically around 70-75nmi altitude.


Or in metric, 1136 W/m² at 130-139 km (about the same as the Sun's radiation).

Thank goodness for other Aussies that talk in real units of measure 

As for the latest FUD, CxP are obviously 'clutching at spanners'.  Quicker the Direct Team can nip this one in the bud, all the better.

[Zapp]

Can someone tell me what FUD means?

Danny Deger

It means fear, uncertainty, and doubt.

actually the info on wikipedia is rather good on this one

http://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt

[Nathan]

Maybe it is a valid critique that needs to be addressed?  Did your source tell you it was an "attack" ... or simply a concern?  The bunker mentality is decidedly not helpful on either side.

No question about it -- its another attack, in the spirit of "getting rid of those meddling kids".

We have a variety of engineering options for making the rear-docking work -- and a number of options which don't even need it (especially if CxP are going to include prop transfer anyway!).

But since when were facts allowed to get in the way of a good round of FUD?   

Ross.

If they really find a huge problem there then can still go to moon with LOR-LOR. I prefer this method since it is a single element launch. EDS+Orion, EDS+Altair. Problem solved. Mass to the moon is reduced but since Altair isn't even designed yet that really shouldn't be an issue!
What hasn't changed is the actual jupiter rocket...

[brihath]

I also want to point out that there are a number of different ways to allow a crew to handle the "reverse docking" of the Altair onto the EDS themselves -- and without having to rely upon any technology like cameras or screens too.

Sounds like a periscope, like on Soyuz

That's one of the options, yes.

Ross.

It seems to me that the current system of a centerline camera mounted in the docking assembly on Shuttle works well.  Has anyone gotten inputs from the Astronaut Corps on how well this has worked?  They have docked this way going back to the Shuttle-Mir missions, so there is a strong heritage.  I do not recall any issues with docking alignment or aborts/retries in the history of the system.  Perhaps there could be an automated system to a certain point with a handoff to manual control or the option of a manual override.

[marsavian]

Not sure yet Paul.   Still gathering information.

Apparently this is all because they were told -- two weeks ago -- that Ares-I is dead (still trying to confirm where that order came from) and so CxP's management are now desperately running around like headless chickens trying to come up with some sort of alternative "2-launch Ares-V-Lite" option in order to protect their already-doomed careers.

And they want to remove us as the leading competition.

Mind you, this does seem to fit perfectly with the other information we've been getting recently:   That CxP have been very quietly  trying to move all of the Ares-I staff over to Ares-V for about two weeks now...   The "effect" becomes clear with this "cause".

Anyway, according to multiple sources who attended a recent TIM, CxP management are now trying to promote another ridiculously expensive 2-launch LOR mission architecture, but with a docking in LEO first, to transfer extra propellant from the Orion's EDS to the Altair's EDS.

Talk about trying to polish a pig!!!

Ross.

If they are going to dock in LEO they might as well make it a proper EOR-LOR mission (and dock the CEV and LSAM) but with propellant transfer which obviously has suddenly now matured as a technology fit for NASA exploration use . What they are proposing is really a EOR-LOR-LOR mission which is unnecessarily complex and more risky.

[Mark S]

If they are going to dock in LEO they might as well make it a proper EOR-LOR mission (and dock the CEV and LSAM) but with propellant transfer which obviously has suddenly now matured as a technology fit for NASA exploration use . What they are proposing is really a EOR-LOR-LOR mission which is unnecessarily complex and more risky.

It seems to me that NASA upper management keeps floating "Plan B" balloons that are actually designed to make the current CxP plan look good.  "What, you don't like Ares-I? Well, then if you don't want that, here is what you will get instead. Ares-I doesn't look so bad, now, does it? Now be a good little boy and run along. Grown-ups are talking..."

So far we have Stumpy, Ares-IV/V, NSC, and now dual mini-Ares-V with fuel transfer. Did I miss any? I've never seen anyone fight the obvious and inevitable so vehemently. Fight to the bitter end, then down with the ship. And for what purpose? What do they hope to accomplish, at this point in time?

Mark S.

[William Barton]

Question: When docking Orion/Altair stack to EDS, do you have to have any functional electrical (or otherer) connection at all, or will mechanical latching be sufficient? In other words, can you radio control the EDS, either from ground or from Orion for its entire part of the mission? It seems likely you can design a mechanical docking system whose radial orientation is irrelevant to its function. As long as no plugs have to be plugged, or fuel lines connected, you just have to make sure the two parts stay locked together during acceleration.

[William Barton]

One of the reasons I have periodically brought up lunar-surface rendezvous is because it solves orbital rendezvous questions, as well at the any-time return question. The cost is a perceived inflexibility in the architecture, but I don't think it's as inflexible as it seems, so long as the landing stage is treated as an independent entity whose job is to land "cargo" on the lunar surface in a single launch architecture. For manned flights, the ERV would be a class of "cargo" (albeit with some abort-related complexities). And you'd have to make sure you designed the ERV/CEV for flexibility that allowed it to fly independently of the landing stage, to ISS, to NEOs, etc. It's great to think about flexible, forward looking architectures involving fuel depots and the like, but I just don't think we are going to get that, this time around. LSR will support exursionary flights to the Moon with small crews, and expeditionary architectures with larger crews for pressurized rovers and bases. So long as the ERV/CEV is designed with flexibility in mind, if the political climate *ever* changes, depots and flights beyond cislunar space aren't forestalled.

[Ben the Space Brit]

[My thinking is that there would be four attachment points, with cameras at each point on Altair looking at their respective attachment points on the EDS.

Cameras may not be necessary.  Something as simple as four laser rangefinders may be all that is necessary.  The Orion's G/N system would be able to judge from differences in return time of the laser beams the angle of approach and distance to go to a literally inhuman level of precision.  Heck, with a radar/laser rendezvous system, the rendezvous could probably be automated (they already do this for cargo delivery to ISS - the Russians have done this with their Progress-class logistical vehicle since the 1970s). 

Two camera could be fitted on the Altair's nadir docking interface with two targets on the EDS interface.  That should be sufficient for alignment in case the automatic rendezvous system goes 'bye-bye'.

[StuffOfInterest]

Question: When docking Orion/Altair stack to EDS, do you have to have any functional electrical (or otherer) connection at all, or will mechanical latching be sufficient? In other words, can you radio control the EDS, either from ground or from Orion for its entire part of the mission? It seems likely you can design a mechanical docking system whose radial orientation is irrelevant to its function. As long as no plugs have to be plugged, or fuel lines connected, you just have to make sure the two parts stay locked together during acceleration.

If power or data connections are required I would expect they could use a variant of the ISS arm's power and data grapple fixture.  One connection gives mechanical, power, and data together.  It could start out mounted on the bottom of the Altair but be detached and left with the JUS/EDS when that section is jetisoned.