Author Topic: DIRECT v2.0 - Thread 3  (Read 1123415 times)

Offline clongton

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Re: DIRECT v2.0 - Thread 3
« Reply #240 on: 01/17/2009 04:05 pm »
For starters, a REAL Mars Sample Return.
How much could a Jupiter 232 send on a trajectory to Mars ?
(that's why I asked payload Vs C3 above ;) )

Assuming 3.8 km/s dv from LEO, about 35 mt. Not including the JUS itself.

Remember that throw weight is not the only limiting factor when sending a lander to mars. The size of the heat shield limits your down mass. Though Direct does have an 8 meter payload shroud which is bigger than the 5 meter shroud on EELV's. I remember seeing somewhere an early Viking plan that had both landers going on top of a single Saturn V launch.

DIRECT has both an 8.4m PLF and a 10m PLF
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline kraisee

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Re: DIRECT v2.0 - Thread 3
« Reply #241 on: 01/17/2009 04:05 pm »
Remember that throw weight is not the only limiting factor when sending a lander to mars. The size of the heat shield limits your down mass. Though Direct does have an 8 meter payload shroud which is bigger than the 5 meter shroud on EELV's. I remember seeing somewhere an early Viking plan that had both landers going on top of a single Saturn V launch.

Just to confirm:   My figures of 31.9mT and 35.7mT were assuming the cargo-only variant of the J-232 using the 10.0m diameter PLF.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline cgrunska

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Re: DIRECT v2.0 - Thread 3
« Reply #242 on: 01/17/2009 04:40 pm »
Reading your opinion of what might happen if a shuttle goes again...let's hope that doesn't occur. I'd like to see humanity off this rock at some point in my life.

Offline robertross

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Re: DIRECT v2.0 - Thread 3
« Reply #243 on: 01/17/2009 04:48 pm »
Reading your opinion of what might happen if a shuttle goes again...let's hope that doesn't occur. I'd like to see humanity off this rock at some point in my life.

Not to nit-pick (okay, I will), but the ISS 'technically' isn't on this rock. We've been leaving this rock quite a few times these past decades to go there...

But as for the moon, unless you plan on leaving us in 15-20 years, you may have a chance. Do you understand Chinese? That's option #2 if you like to follow along... lol.

Offline Fequalsma

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Re: DIRECT v2.0 - Thread 3
« Reply #244 on: 01/17/2009 04:54 pm »
Can't hurt you to learn.  lol.


Do you understand Chinese? That's option #2 if you like to follow along... lol.


Offline zapkitty

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Re: DIRECT v2.0 - Thread 3
« Reply #245 on: 01/17/2009 05:46 pm »
Quote from: kraisee
  It would be a gradual change-over, but the cost for lifting 60 tons of cargo to LEO is a very small price for any nation to join the exclusive club of moon-walkers -- its a very small price to pay for that prestige, so there is likely to be a nice long waiting list.

Sorry, Ross, but you failed to include that it could all be done by cheap unmanned probes. Yes, you fail as a "Space is a Waste" commenter. You should go back and try again. 

Quote from: kraisee
Combined with the level of demand for such seats being relatively high (<$300m to join the 250,000 mile high club),

Too little and too late. You need to hammer home that no astronaut has ever brought back any new discoveries from the moon that couldn't have been done faster and cheaper by machines.

We await your next effort though...

Offline kraisee

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Re: DIRECT v2.0 - Thread 3
« Reply #246 on: 01/17/2009 05:58 pm »
I'll refer you to Steve "Mars Exploration Rover" Squyres comments regarding Human and Robotic Surface Science:

"robotic exploration is what I do. However, I feel that the best exploration is only possible with humans"

and

"The rovers do in a day what a skilled field geologist can do in 30 seconds".

I recall seeing precisely that on NASA TV one time.   It was shortly after Spirit completed its basic 90 day mission.   They prepared a bit of rough land in the same way as the Mars-scape which Spirit had traversed, then dressed a geologist up in a space suit, gave him the tools he would need and told him what he needed to do.   He was finished in about 40 minutes having completed every single bit of science which had taken the Rover 90 days to complete.   The comment was made that a crew of 6 exploring Mars for 6 months would produce more science return than a thousand Rovers could in ten years.


But this is getting completely off the topic.

The goal of DIRECT is to create a sustainable architecture which we can afford to really use, which involves the international partners in a way that is valuable, without handing the keys over, and which works within the framework as laid out by the Presidential and Congressional authorizations.

And make no mistake; returning humans to the moon is the policy of both the White House and the Hill.

Ross.
« Last Edit: 01/17/2009 06:35 pm by kraisee »
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline William Barton

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Re: DIRECT v2.0 - Thread 3
« Reply #247 on: 01/17/2009 06:10 pm »
"Machines can do it faster and cheaper" is one of the oldest and least well-thought-out arguments of the Space Age. Sure you can send a modern-day equivalent of Mariner IV to take a couple of dozen snapshots of Mars for $100mln, but you can't send a human to Mars for much under $100bln. But what would be the human equivalent of Mariner IV? Send an astronaut in a Mercury capsule with a Brownie Instamatic? And what's the machine equivalent of a manned flight to Mars? A fully autonomous robotic probe imbued with infinitely complex artificial intelligence? How much would it cost to build that machine, $100trln? Does anyone think the Soviet Luna program did more, better science than Apollo? It certainly didn't do it faster, and not a whole lot cheaper. Machines are best if you only want to do a little bit of science. Humans are best if money is no object. Those are very different goals.

Offline zapkitty

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Re: DIRECT v2.0 - Thread 3
« Reply #248 on: 01/17/2009 06:37 pm »
I'll refer you to Steve "Mars Exploration Rover" Squyres comments regarding Human and Robotic Surface Science:

*sigh*

Your snark detector needs work...

... in short: You might want to avoid giving the "Wasters" extra ammo in these forums by using the very phrases they use to denigrate "manned" spaceflight.

("manned" in scare quotes because of course these are evolved from the old "Space is Wasted" types... just like the "Intelligent Designers" evolved from "Creationists".)

Really... your phrasing matched theirs exactly... reading too much NY Times, lately? :)
 

Offline zapkitty

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Re: DIRECT v2.0 - Thread 3
« Reply #249 on: 01/17/2009 06:44 pm »
Errr... I know Direct's taken a lot a flack but see previous notes about snark detectors...

Machines are best if you only want to do a little bit of science. Humans are best if money is no object. Those are very different goals.

And while we're at it, was this a typo or just a faux pas?

"Humans are best if money is no object."

.... I can hear the Wasters speed-dialing their congresscritters now...

Offline Lab Lemming

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Re: DIRECT v2.0 - Thread 3
« Reply #250 on: 01/17/2009 08:29 pm »
"Machines can do it faster and cheaper" is one of the oldest and least well-thought-out arguments of the Space Age. Sure you can send a modern-day equivalent of Mariner IV to take a couple of dozen snapshots of Mars for $100mln,

If we didn't have those snapshots, we'd be designing the Martian LM for canal landings.

Given the crash landing rate for Mars, I'm pretty happy we haven't tried putting people there yet.

Quote
"The rovers do in a day what a skilled field geologist can do in 30 seconds".

A friend of mine who commands rovers came back with, "It may take me a day, but how long will it take your geologist to get there?"
Quote
Too little and too late. You need to hammer home that no astronaut has ever brought back any new discoveries from the moon that couldn't have been done faster and cheaper by machines.

The Russians tried to launch a robotic mission that would have returned sample before Apollo 11.  It blew up.  Try searching the geologic literature for lunar science papers, and tell me what the apollo / lunknod ratio is.

Offline clongton

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Re: DIRECT v2.0 - Thread 3
« Reply #251 on: 01/17/2009 08:38 pm »
AFAIK, the only sample return mission that actually worked right was manned; Apollo 11
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Jorge

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Re: DIRECT v2.0 - Thread 3
« Reply #252 on: 01/17/2009 08:43 pm »
AFAIK, the only sample return mission that actually worked right was manned; Apollo 11

Luna 16, 20, and 24 were successful, but returned a total of only 0.326 kg of samples.

Apollo 11 alone returned 22 kg and the Apollo program returned a total of 381 kg.
JRF

Offline Nathan

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Re: DIRECT v2.0 - Thread 3
« Reply #253 on: 01/17/2009 08:52 pm »
Quote from: kraisee
  It would be a gradual change-over, but the cost for lifting 60 tons of cargo to LEO is a very small price for any nation to join the exclusive club of moon-walkers -- its a very small price to pay for that prestige, so there is likely to be a nice long waiting list.

Sorry, Ross, but you failed to include that it could all be done by cheap unmanned probes. Yes, you fail as a "Space is a Waste" commenter. You should go back and try again. 

Quote from: kraisee
Combined with the level of demand for such seats being relatively high (<$300m to join the 250,000 mile high club),

Too little and too late. You need to hammer home that no astronaut has ever brought back any new discoveries from the moon that couldn't have been done faster and cheaper by machines.

We await your next effort though...


If the goal is to sends humans to space you can't do that with just robots....
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline clongton

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Re: DIRECT v2.0 - Thread 3
« Reply #254 on: 01/17/2009 09:03 pm »

A friend of mine who commands rovers came back with, "It may take me a day, but how long will it take your geologist to get there?"

The answer is approximately the same amount of time.
Trajectories are trajectories and whether it's a robot or a human crew, they all have to obey the same laws of motion.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Jim

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Re: DIRECT v2.0 - Thread 3
« Reply #255 on: 01/17/2009 09:08 pm »
.... I can hear the Wasters speed-dialing their congresscritters now...

They don't have any impact nor are there very many

Offline Khadgars

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Re: DIRECT v2.0 - Thread 3
« Reply #256 on: 01/17/2009 09:26 pm »
Quote from: kraisee
  It would be a gradual change-over, but the cost for lifting 60 tons of cargo to LEO is a very small price for any nation to join the exclusive club of moon-walkers -- its a very small price to pay for that prestige, so there is likely to be a nice long waiting list.

Sorry, Ross, but you failed to include that it could all be done by cheap unmanned probes. Yes, you fail as a "Space is a Waste" commenter. You should go back and try again. 

Quote from: kraisee
Combined with the level of demand for such seats being relatively high (<$300m to join the 250,000 mile high club),

Too little and too late. You need to hammer home that no astronaut has ever brought back any new discoveries from the moon that couldn't have been done faster and cheaper by machines.

We await your next effort though...


Sending probes doesn't advanced the technology to send people beyond LEO.  Besides the Moon isn't a good example of probe vs human because as you said sending a probe there is quite easy.

The moon is chosen not because of it's significant but it's proximity to earth which will allow mankind to obtain the experience and know how to operate far from the earth.

Now as we move onto Mars, sending probes that travel a few feet per day or can only scoop ice directly around it doesn't compare to what a human expedition could do while they were on the surface.  Not to mention sending probes to Mars is quite expensive in it's own right and a sample return mission is through the roof. 

Never mind the technological advancements that go far beyond space programs that benefit virtually every single person on the planet are obtain through such endeavors on top of all the highly skilled jobs that are created.

The argument not to go is the one that doesn't hold much water.
Evil triumphs when good men do nothing - Thomas Jefferson

Offline William Barton

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Re: DIRECT v2.0 - Thread 3
« Reply #257 on: 01/17/2009 09:46 pm »
One of the false dichotomies in the manned vs. unmanned discussion is the idea that proponents of manned space exploration are opponents of unmanned space exploration. In fact, I don't know of anyone who thinks humans should go to Mars who is opposed to precursor robotic probes. The point of the difference is, there *are* some thing unmanned probes do better. One of those things is getting initial baseline data relatively cheaply. Sample return is probably not one of those things, though.

The flip side, though, is there are many unmanned proponents who are adamantly opposed to manned spaceflight.

Offline zapkitty

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Re: DIRECT v2.0 - Thread 3
« Reply #258 on: 01/17/2009 09:49 pm »
Quote from: zapkitty
.... I can hear the Wasters speed-dialing their congresscritters now...
They don't have any impact nor are there very many

Perhaps. And the current crop of Wasters whose battle cry is "Unmanned!" have certainly been forced by reality to shift from the "Space is Waste" meme of their forebears...

And hopefully it will stay that way but... returning to the thrust of my original snark...

Words matter. With Americans still basically unaware of the extent of the megatons of economic crap that's scheduled to hit their collective fan in the next few years, distressed folks will be a fertile breeding ground for the Wasters.

So perhaps caution in any wording exhorting the eliteness and exclusivity of space flight would be prudent. Especially if your actual goal is to expand spaceflight and reduce the cost of access.

Yes, national prestige will be enhanced, but there are ways of describing it that won't piss off economically pressured citizens quite so much.

Griffin is (should be) over. Bush is (should be) over. But if chance strikes up a populist proxmire movement as ill-informed as the Wasters...

And you could have actual proxmires... perhaps gerrymandering the contractor states might not be enough to keep off some new-fledged congresscritters ready to score a few hundred cheap shots off of Good Ole NASA...

If... maybe... but as Direct should (hopefully) have a shot at a fair hearing now it would seem to be a good idea to be more careful in wording. An eye to the future you might say. 



Edit: robertross pointed out that if I meant a full review I should have said so instead of using the phrase "fair hearing". True! :)
« Last Edit: 01/18/2009 12:19 am by zapkitty »

Offline robertross

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Re: DIRECT v2.0 - Thread 3
« Reply #259 on: 01/17/2009 10:25 pm »
{snip}
If... maybe... but as Direct should (hopefully) have a shot at a fair hearing now it would seem to be a good idea to be more careful in wording. An eye to the future you might say. 


They already did. They met with the transition team for NASA. If you meant a full review, that's different.

As a personal clip, I'm glad Jim is putting some correctness in here.

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