DIRECT v3.0 - Thread 1

[gladiator1332]

They better pick Direct...I mean, what the hell am I going to do if we don't have any more Direct threads.

Think of whatever they pick as quasi-Direct, almost Direct.  They may even put the NASA emblems on different spots just to say it's not Direct  I sure don't think it will be the status quo.  I'm sure there will be plenty of things for many good threads to come.

We can call them "Not-Direct" threads. 

[Eric Hedman]

They better pick Direct...I mean, what the hell am I going to do if we don't have any more Direct threads.

Think of whatever they pick as quasi-Direct, almost Direct.  They may even put the NASA emblems on different spots just to say it's not Direct  I sure don't think it will be the status quo.  I'm sure there will be plenty of things for many good threads to come.

We can call them "Not-Direct" threads. 

Absolutely

[cixelsyD]

Before you're planning books, remember the Commission and Bolden still have some decision making to do, I'd wait on the champagne before everything is certain.

You may end up with Ares V + Not Shuttle-C..

[Drapper23]

"The Augustine Commission and Aerospace Corporation are in essence trying to create an objective baseline on which to evaluate all cost proposals. Although it is still preliminary we believe that the Aerospace Corporation has been able to validate our figures."
 (Ross Tierney-July 23,2009 Next Big Picture Interview)  This statement is extremely significant. In my opinion, it means that Direct now stands an extremey good chance of becoming the next US Manned Spacelight Launch System.  http://nextbigfuture.com/2009/07/interview-with-ross-tierney-of-direct.html

[gladiator1332]

Before you're planning books, remember the Commission and Bolden still have some decision making to do, I'd wait on the champagne before everything is certain.

You may end up with Ares V + Not Shuttle-C..

You sir are correct, it is a bit soon to begin celebrating. However, since all of this began, this is about as excited as I have seen this Direct thread.

Things are happening and falling into place. It can go any way this August, but I still have my fingers crossed.

[drdave]

Unacceptable to many, but the only guy that really matters is the President, and he really hasn’t shown much public interest one way or the other.  Even during the Apollo 11 celebrations on Monday, the Apollo astronauts kept dropping “hints” that we need to go back to the moon and/or Mars, and the President kept sorta diverting the discussion to NASA will continue to lead in science but no specific mention of “human exploration”. 

I would have been surprised if he said anything significant.  He convened a Presidential Commission to look at the issue and offer up alternatives, but the deadline for that is still in the future.  By making remarks of any significance, he would have been jumping the gun.  Frankly, I was surprised that he went for the photo op with them.

Anybody who has watched Obama operate over the past six months knows he will let the process run out and then exert his influence at the moment when things are balanced and can tip either way.  Maximum effect from minumum (or maximum) effort.  Look at the way the health care issue has played out.  He has let Congress futz around with the issue until they have used uo their playing field.  He has now begun to bring his effort to bear.

He plays his hand close to the vest.  He smiles, makes small talk, and then moves.

I doubt any of us knows what he will do.  He may not have decided yet.  Not enough information to make an intelligent, and yes, a politically motivated decision.

So keep up the media campaign.  Keep up the pressure.  Write your congress critters (long hand, in ink).  Letters to editors, interviews, whatever you can do.

[Steven Pietrobon]

I was thinking you might have some ideas about avoiding the dock.

I havn't though of anything that hasn't been proposed before. A crazy idea is to have the PLF attached and have Orion dock with the EDS. This would involve large stresses on Orion, due to the weight of the Altair and the PLF above it.

If one Jupiter carries both Altair and Orion, then its EDS does not have enough propellant to go through TLI. You either transfer propellant from another EDS (what von Braun called tanking mode) or have the other EDS dock with the first stack (what von Braun called connecting mode). Von Braun preferred tanking mode.

Another solution is developing a Nova class launch vehicle to launch Altair or Altair/Orion (like Saturn-V). However, this involves a huge development cost. There's also LOR-LOR. The latter was proposed by NSC so it should work for Jupiter. Ross says there's a 20% performance loss though due to launching two EDS stages to the Moon.

[Michael Bloxham]

There is another issue with both NSC and Ares V which I think is being overlooked but may become increasingly important due to the recent refocusing to a manned mars mission by Bolden (see quote below) and others: Mars EDL issues.

If we want to land anything of reasonable size on the surface of Mars, you need a big heatshield (at least 10m, preferably 12+) and therefore a big payload fairing.

NSCs maximum PLF is 7.5m so thats not going to work. I think the maximum payload you can land with a 7m heatshield is around 7 tonnes or so...

NSC + Ares V goes against all logic (2 independent development programs, etc) so I don't think that'll ever happen.

Ares V by itself meets the payload volume criteria, with PLFs up to 12m or so. But even with a 12m heatshield, your surface payload is maybe only 20 tonnes or so max.

My sources tell me that payload delivered to Mars' surface is typically 17% of total mass delivered to LEO, so we can multiply that figure by 1/0.17 to find the launch vehicle that we need.

For that 20 tonne payload, it works out that we only need a launch vehicle with a 117 tonnes to LEO capability. Clearly the Ares V vehicle is way oversized for this.

But I believe it just so happens that the Jupiter rockets, with their allowance for big PLFs, would be quite suitable for Mars missions.

So in short: Shuttle C is too small. Ares V is too big. Both together are too expensive. But the Jupiter is just right?

Sounds familiar huh?

- Mike

--------------

From here: http://www.google.com/hostednews/ap/article/ALeqM5jc2d_p1DHvR8srpLfst9HA7oOBlQD99J1RG02
 

Bolden said his main job over the next few months will be to champion an "agreed-upon compromise strategy to get first to Mars and then beyond. And we don't have that yet."

Edit: Fixed breaks in link

[simon-th]

So in short: Shuttle C is too small. Ares V is too big. Both together are too expensive. But the Jupiter is just right?

With current technology, none of the different heavy lift vehicles (NSC, Ares V or Jupiter) proposed can provide lift capacity volume-wise of a large enough heatshield to allow decently sized modules (50t+) to be landed on Mars with a conventional approach. Actually, the upper limit on the current technology (Viking shaped heatshield) used for Mars landings is about 2tons whatever you do.

For a Mars mission, we will have to come up with new technology in any event. There are many concepts, from additional inflatable heatshields to aerobracking into orbit first and then do heatshield + powered descent etc. etc. Even looking at a several segment heatshield to get to 25m+ diameter is an option.

However, a Mars mission according to current planning (with Moon first) is at least 30 years out. Using payload volume and diameter constraints as an argument against heavy lift rockets solely because of heatshield issues on a potential Mars missions, when we don't even have the technology to land anything in the 50t range on the Mars surface no matter which heatshield approach we use right now is a bit far-fetched in my opinion.

[gladiator1332]

So in short: Shuttle C is too small. Ares V is too big. Both together are too expensive. But the Jupiter is just right?

With current technology, none of the different heavy lift vehicles (NSC, Ares V or Jupiter) proposed can provide lift capacity volume-wise of a large enough heatshield to allow decently sized modules (50t+) to be landed on Mars with a conventional approach. Actually, the upper limit on the current technology (Viking shaped heatshield) used for Mars landings is about 2tons whatever you do.

For a Mars mission, we will have to come up with new technology in any event. There are many concepts, from additional inflatable heatshields to aerobracking into orbit first and then do heatshield + powered descent etc. etc. Even looking at a several segment heatshield to get to 25m+ diameter is an option.

However, a Mars mission according to current planning (with Moon first) is at least 30 years out. Using payload volume and diameter constraints as an argument against heavy lift rockets solely because of heatshield issues on a potential Mars missions, when we don't even have the technology to land anything in the 50t range on the Mars surface no matter which heatshield approach we use right now is a bit far-fetched in my opinion.

I know Bolden wants Mars in his lifetime. However, I always feel Mars is regarded as "tomorrow land" and is always 30 years on the horizon. The one good thing about the VSE was we would get our exploration gears going again with the Moon, and that would lead to other greater things.
The VSE is not flawed, the vehicles picked to carry it out were flawed. I would hate to see some "Mars Program" with the ISS. That's what NASA has been trying to the last 15 years. Everything we do in LEO is said to be preparing for Mars someday, but we are never actually building and designing the vehicles that will carry out the mission.

Direct doesn't abandon the VSE. It gives us an architecture that can actually make it work with the dollars at hand.

[Michael Bloxham]

So in short: Shuttle C is too small. Ares V is too big. Both together are too expensive. But the Jupiter is just right?

With current technology, none of the different heavy lift vehicles (NSC, Ares V or Jupiter) proposed can provide lift capacity volume-wise of a large enough heatshield to allow decently sized modules (50t+) to be landed on Mars with a conventional approach. Actually, the upper limit on the current technology (Viking shaped heatshield) used for Mars landings is about 2tons whatever you do.

I'm not that pessimistic. But in any case we can see that PLF volume is the driver, not mass. So NSC is still too small, and Jupiter is at least as good as Ares V.

- Mike

[simon-th]

Direct doesn't abandon the VSE. It gives us an architecture that can actually make it work with the dollars at hand.

1. I think costs are a subject to debate when it comes to DIRECT. At least people like John Shannon think the costs are underestimated (like all costs of any large NASA development project are underestimated at first...)

2. As I said above, I don't think either Ares V or NSC means you can't do a Mars mission.

P.S. I am a proponent of a two-launch scenario with an in-line SDLV. I still think we shouldn't discredit other options with far-fetched arguments. The main arguments for any in-line SDLV are payload mass, only 1 launcher to be developed and some benefits on the time schedule as well as probably better safety numbers for crewed launch vs. NSC (and maybe even better than Ares I).

[A_M_Swallow]

What diameter Mars heat shield can the J-130 lift?  Assume a made-to-measure PLF.

[zapkitty]

What this actually all leads to, once the MSFC AutoFUD response is disabled, is the fact that spaceships are best assembled in space

ISS itself is really not appropriate... not so much because of its inclination but more because they're supposed to be doing micro-g work there and that really doesn't go well with multi-ton masses being juggled at odd intervals....

... yes, the irony of that statement as applied to ISS does not escape me...

A mini-shipyard adjacent to ISS would actually be sensible and leverage several factors... perhaps sufficiently to balance out the other issues associated with that inclination... so figure it won't be done.

(If NASA chooses Direct then you must figure that it's used up its quota of common sense for the decade )

Can a mini-shipyard... say one of the proposed shuttle payload transport pallets with added attitude control, electronics bay, cameras, a couple of Canadarms and a couple of SLASR arrays... can it make do at 23 degrees inclination? It's all basic stuff that's either ready to go or already had some research done...

Advantages: with the Orion teleoperating the arms the various components of the lunar stack can have any sort of stack rearrangement and prop tranfer done while the Orion is out of the immediate danger zone... and when everything is ready the Orion just docks to Altair as the cherry on top and off they go

... later expansions could have a converted JUS experimental depot parked adjacent for actual refueling operations and/or perhaps a MPLM serving as a control node and pressurised and temperature-controlled auxiliary supplies store with a nitrogen atmosphere and an airlock...  (yes, it's a valid mass saver: less goods hauled up equals more actual Orion launched.)

*(added: water!)

... Spacedock...

... well, a mini-spacedock... 50 frackin' years overdue but it'd cover the basics and be a valid beginning...

And this too could be an eventual part of Direct... albeit not baselined... once the FUD generators are cleared away.

The "Next Von Brauns" my ass... not a single friggin' orbital assembly facility anywhere in those plans.

Okay... I vented... but any errors or obvious showstoppers?

Edit: this'n'that

[zapkitty]

What diameter Mars heat shield can the J-130 lift?  Assume a made-to-measure PLF.

... note: questionable data follows: Ross had mentioned a while back that previous musings on 15m diameter fairings looked like it was pushing the limit... actual applicability of that to the here-and-now is unknown...

But folded that would give you a 30 meter heat shield...

[Nathan]

I would have been surprised if he said anything significant.  He convened a Presidential Commission to look at the issue and offer up alternatives, but the deadline for that is still in the future.  By making remarks of any significance, he would have been jumping the gun.  Frankly, I was surprised that he went for the photo op with them.

Let's give the Augustine Commission time to do their work and make their recommendations.  His new NASA Administrator has been very vocal about where his sentiments lie, and I believe Charlie Bolden is way too smart to blindside the President with his opinions.

I think we just need to give the process time to work.  The DIRECT team got what they wanted with the hearings, an impartial review of the alternatives.

You are not going to hear Obama give any "we choose to go to the Moon" type speeches. To do so would be career suicide. Look what happened to Bush when he announced the VSE...every late night talk show host poked fun at it.
No wonder there were no more Moon related speeches from Bush.
Certain groups are looking to jump all over Obama for anything. So called "wasteful spending" on a Moon mission would be easy cannon fodder.

So it is all on the commission to find a plan that can work on a reasonable budget and time clock, and will not need much rallying from the President.

The VSE relied on a growth in funding. That needed political support and congressional interest...both of which will never happen. It is the world we live in and anyone who tries to work a plan around anything but this, then you are living in dreamland.


[/quote]

It can be promoted as "economic stimulus", Which would be true.

[simon-th]

But folded that would give you a 30 meter heat shield...

There are lots of different folding techniques. You can get a 30m heatshield into a 7.5m diameter payload fairing. You basically have a core heat shield of 7.5m and segments from the outer heat shield folded upright around it all in the 10m length.
 
And no, you don't need an EVA to assemble a segmented heathshield. Actually folding techniques have been used in space forever and they work. Automatic bolting works as well.

I've always wondered why people dislike the segmented, folded heatshield for Mars payloads approach so much. As far as I see it, as long as we stay with conventional Mars descent techniques (that is a heatshield and later on parashutes and some powered descend for the last part) going with segmented heatshields makes the most sense. Rather than having to design your modules around constraints of a 10m, 12m or 15m heathshield (depending on the diameter of your payload fairing) you can just design your modules and design the appropriately sized heatshield for it.

[zapkitty]

But folded that would give you a 30 meter heat shield...

I've always wondered why people dislike the segmented, folded heatshield for Mars payloads approach so much.

That is the legacy of NASA.

People don't want the trouble of bringing in something new to an existing process because the usual NASA first response is drown the idea in "can't do that's" (whether truly relevant or not) and the usual second response by NASA to persistent followups is to bite heads off.

And yes, that's sad.

[William Barton]

Slightly OT, the ideal PR name for an orbital shipyard would be "Stardock." It's the name of an old Fritz Leiber story (about the mountain on Nehwon where the gods built and launched the stars), but will resonate favorably with the taxpaying public, that watches TV shows named "Star (Whatever)."

[brihath]

I just read an interesting article in AW&ST regarding manned launch alternatives.  The article focused largely on NSC, but the main thrust (no pun intended) of the article was that PWR said restarting the SSME line was very doable.  A reduced cost SSME derivative could be available within 3-4 yrs at a cost of 2/3 to 4/5 of SSME cost, depending on volumes.  It would be a little more expensive than RS-68, but "in the ball park".

The bottom line to me is that the industry mindset is moving away from Ares I to an SDLV.  I believe that bodes well for DIRECT.