SpaceX Dragon spacecraft for low cost trips to the Moon.

Byeman said:
Again, what do these have to do with the OP? I see nothing about the Dragon

The discussion of about the legal and financial aspects of off-world mining is going rather far afield from the original topic. I'll open another thread on this new topic, and leave it to the moderators to place it in the right subforum.
The original purpose of the thread was to show low cost means exist for manned missions to the Moon, at the few hundred million dollar range if using the Falcon Heavy. However, because I believe off-world mining might finally be the "killer app" that makes routine manned space travel necessary, I wanted to show also in the original post it would easy and cheap to do unmanned space missions to prove definitively, via sample returns, that almost unimaginable wealth does indeed exist in the Moon and asteroids. Such sample return missions, I argue, can also be undertaken at costs in the few hundred million dollars range. This is in contrast to the billion dollar missions NASA is proposing to return samples from asteroids and from the permanently shadowed polar regions of the Moon.
The sample return missions would not use the Dragon because that would be too heavy for the low cost, low mass missions. Granted, it is a legitimate question if this should be discussed in the same thread as one on the low cost manned missions. I'll open up a separate thread on that as well. BTW, I'm now convinced that the holy grail of planetary missions Mars sample return also can be done for costs in the few hundred million dollar range rather than the ca. $10 billion missions NASA has been proposing:

NASA has until summer to come up with Mars strategy.
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: February 28, 2012
http://spaceflightnow.com/news/n1202/28marsplanning/

NASA wants mission to bring Martian rocks to Earth.
May 18, 2010
http://phys.org/news193383644.html


Bob Clark
 
RGClark said:
...
The original purpose of the thread was to show low cost means exist for manned missions to the Moon, at the few hundred million dollar range if using the Falcon Heavy. However, because I believe off-world mining might finally be the "killer app" that makes routine manned space travel necessary, I wanted to show also in the original post it would easy and cheap to do unmanned space missions to prove definitively, via sample returns, that almost unimaginable wealth does indeed exist in the Moon and asteroids. Such sample return missions, I argue, can also be undertaken at costs in the few hundred million dollars range. This is in contrast to the billion dollar missions NASA is proposing to return samples from asteroids and from the permanently shadowed polar regions of the Moon.
The sample return missions would not use the Dragon because that would be too heavy for the low cost, low mass missions. Granted, it is a legitimate question if this should be discussed in the same thread as one on the low cost manned missions. I'll open up a separate thread on that as well...

Disentangling the low cost manned flight posts and the low cost unmanned mission posts in this thread would be a problem. Some people have advised that I should open up a blog for such technical discussions - sometimes meant as a constructive criticism, sometimes not. In any case I have decided to do so. I'll leave such detailed discussions to the blog.
For off-world mining as a "killer app" for routine space flight, we will need low cost super heavy lift, and low cost manned flight. On the blog so far are posts discussing creating a super heavy lift vehicle at the few hundred million per launch range, compared to NASA's SLS at ca. $10 billion per launch(!), and of manned lunar missions also at the few hundred million per launch range, compared NASA's Constellation program at $100 billion total.

Low cost HLV.
http://exoscientist.blogspot.com/2012/05/low-cost-hlv.html

SpaceX Dragon spacecraft for low cost trips to the Moon.
http://exoscientist.blogspot.com/2012/05/spacex-dragon-spacecraft-for-low-cost.html

Comments on the blog posts and on improving the blog are invited.


Bob Clark
 
failboat.jpg

http://www.youtube.com/watch?v=wJEIAR-76A0
 
Offizial: after ignition engine nr 5° of first stage of Falcon 9
show abnormal high pressure and launch computer shutdown the launch
 
on the radio they said that it was going to the spacestation is this correct
 
The launch was aborted at T-0.5s because they detected a problem. That's not a failure, that's proper engineering.

Yes, the flight will go to the ISS.
 
Hobbes said:
The launch was aborted at T-0.5s because they detected a problem. That's not a failure, that's proper engineering.

Yes, the flight will go to the ISS.

Technically it was a failure that was kept from developing into full blown disaster by proper engineering. One advantage of liquid engines over solid motors. Could have been, "whoops, overpress. . . .nevermind".
 
Michel Van said:
Offizial: after ignition engine nr 5° of first stage of Falcon 9
show abnormal high pressure and launch computer shutdown the launch

I'm not sanguine about such large numbers of engines on a rocket intended to make space flight routine.
I have mentioned before there is nothing especially innovative about the SpaceX designs. The engines they're using are of no better efficiency than the ones used on the original Atlas from the 1960's. And the lightweight stages come from techniques known from the 1970's. SpaceX has said they don't want to patent their designs because that would give for example the Chinese greater ease in copying them. However, I wonder if the real reason is that they are just using techniques already known for decades.
What is innovative is that they used good business practice in privately developing their vehicles, which led them to have reduced development costs by up to 90%(!) In the space industry, that is innovative. But of course in the business world there is nothing innovative about that either.
So any of the large aerospace companies in the world could duplicate the SpaceX low development costs except they would be better off just using the much better efficiency (russian) engines now existing, resulting in needing fewer engines plus they wouldn't have the development costs of building entirely new engines. In other words, any of the world's large aerospace companies could develop equivalent launchers to those of SpaceX for lower prices to orbit by likewise using good business practice for privately developed rockets.


Bob Clark
 
RGClark said:
1. I'm not sanguine about such large numbers of engines on a rocket intended to make space flight routine.

2. I have mentioned before there is nothing especially innovative about the SpaceX designs. The engines they're using are of no better efficiency than the ones used on the original Atlas from the 1960's. And the lightweight stages come from techniques known from the 1970's. SpaceX has said they don't want to patent their designs because that would give for example the Chinese greater ease in copying them. However, I wonder if the real reason is that they are just using techniques already known for decades.

3 .What is innovative is that they used good business practice in privately developing their vehicles, which led them to have reduced development costs by up to 90%(!) In the space industry, that is innovative. But of course in the business world there is nothing innovative about that either.
So any of the large aerospace companies in the world could duplicate the SpaceX low development costs except they would be better off just using the much better efficiency (russian) engines now existing, resulting in needing fewer engines plus they wouldn't have the development costs of building entirely new engines. In other words, any of the world's large aerospace companies could develop equivalent launchers to those of SpaceX for lower prices to orbit by likewise using good business practice for privately developed rockets.

1. What you think or feel carries no merit. You are not an expert on spaceflight by any stretch. I wouldn't even say that you are informed about the subject.

2. You were wrong when you mention it.

3. Wrong again. Spacex practices are not proven yet. Their costs are climbing and will continue to. Nor could large aerospace companies replicate what they had done due to overhead and unions.
 
Byeman said:
RGClark said:
1. I'm not sanguine about such large numbers of engines on a rocket intended to make space flight routine.
2. I have mentioned before there is nothing especially innovative about the SpaceX designs. The engines they're using are of no better efficiency than the ones used on the original Atlas from the 1960's. And the lightweight stages come from techniques known from the 1970's. SpaceX has said they don't want to patent their designs because that would give for example the Chinese greater ease in copying them. However, I wonder if the real reason is that they are just using techniques already known for decades.
3 .What is innovative is that they used good business practice in privately developing their vehicles, which led them to have reduced development costs by up to 90%(!) In the space industry, that is innovative. But of course in the business world there is nothing innovative about that either.
So any of the large aerospace companies in the world could duplicate the SpaceX low development costs except they would be better off just using the much better efficiency (russian) engines now existing, resulting in needing fewer engines plus they wouldn't have the development costs of building entirely new engines. In other words, any of the world's large aerospace companies could develop equivalent launchers to those of SpaceX for lower prices to orbit by likewise using good business practice for privately developed rockets.

1. What you think or feel carries no merit. You are not an expert on spaceflight by any stretch. I wouldn't even say that you are informed about the subject.
2. You were wrong when you mention it.
3. Wrong again. Spacex practices are not proven yet. Their costs are climbing and will continue to. Nor could large aerospace companies replicate what they had done due to overhead and unions.

The development costs being 1/4th to 1/10th of that of usual NASA rockets have been confirmed by NASA.
For the launch cost of the Falcon 9 to match those of the usual American rockets the launch cost would have to rise to $100 million per launch from $50 million per launch for their commercial launches (not carrying the Dragon.) If that were to happen probably most people including Elon Musk would consider their attempt to cut the cost of space by taking a more commercial approach to launcher development to have failed. It will be interesting to see what are indeed the consistent prices they charge when they do start making their commercial launches.


Bob Clark
 
RGClark said:
The development costs being 1/4th to 1/10th of that of usual NASA rockets have been confirmed by NASA.
For the launch cost of the Falcon 9 to match those of the usual American rockets the launch cost would have to rise to $100 million per launch from $50 million per launch for their commercial launches (not carrying the Dragon.) If that were to happen probably most people including Elon Musk would consider their attempt to cut the cost of space by taking a more commercial approach to launcher development to have failed. It will be interesting to see what are indeed the consistent prices they charge when they do start making their commercial launches.

NASA hasn't developed a rocket in this class for a half a century.
time is going to tell about the eventual cost of the Falcon 9
 
Lift off.

The Falcon 9 rose from Launch Complex 40 at Cape Canaveral Air Force Station, Fla., at 3:44 a.m., EST, thundering away on a northly arc through a darkened sky. The Dragon separated from the two-stage launcher on schedule, and a successful solar array deployment followed at 11 minutes, 19 seconds into flight. The ISS orbited 250 miles over the North Atlantic Ocean east of Newfoundland as the Falcon 9 departed. A trouble free countdown and departure initiated a planned nine-day mission that promises to bring the unpiloted Dragon within 1.5 miles of the six person space station early Thursday for a critical series of navigation and communications checks If all goes well, the Dragon will retreat to a point about 125 miles above and behind the station, returning early Friday for more systems tests before moving within range of the orbiting laboratory’s Canadarm 2. Station astronauts Don Pettit, of NASA, and Andre Kuipers, of the European Space Agency, will be posted at a control console in the statio’s Cupola observation deck ready to grapple the freighter and berth it to the U. S. segment Harmony module shortly after 11 a.m., EDT. Dragon, flying under the banner of NASA’s Commercial Orbital Transportation Services program, is scheduled to remain docked until May 31. The length of the stay, once intended to be twice as long, is constrained by an increasing solar beta angle, which exposing the orbital plane of the space station to more heat from the sun. Efforts to begin the mission on Saturday were aborted a half second before lift off, when the Falcon 9 flight control system detected a slight overpressure in the No. 5 Merlin first stage engine. Engineers identified a faulty nitrogen check value in the first stage power plant. The faulty valve, which was allowing unwanted nitrogen to flow into a liquid oxygen fill line, was replaced. An post shutdown analysis indicates the May 19 launch could have proceeded safely, according to SpaceX president Gwynne Shotwell. But she added, “The computer software did what it was supposed to, which is good.” The first stage is powered by nine SpaceX developed Merlin liquid oxygen/kerosene engines, the second stage by one of the power plants. Dragon is carrying about 1,014 pounds of non critical cargo, including food, computer equipment and student experiments within a Nanoracks Module. If the linkup is successful, the capsule will depart the station with about 1,400 pounds of experiment samples, space suit gear and hardware slated for refurbishment. Once undocked, Dragon will re-enter the Earth’s atmosphere, descending under parachute into the Pacific Ocean several hunder miles off the southern California coast. SpaceX plans to recover the re-usable Dragon capsule.
 
Byeman said:
RGClark said:
The development costs being 1/4th to 1/10th of that of usual NASA rockets have been confirmed by NASA.
For the launch cost of the Falcon 9 to match those of the usual American rockets the launch cost would have to rise to $100 million per launch from $50 million per launch for their commercial launches (not carrying the Dragon.) If that were to happen probably most people including Elon Musk would consider their attempt to cut the cost of space by taking a more commercial approach to launcher development to have failed. It will be interesting to see what are indeed the consistent prices they charge when they do start making their commercial launches.

NASA hasn't developed a rocket in this class for a half a century.
time is going to tell about the eventual cost of the Falcon 9

People forget that Ariane 5 (and Ariane 4 before it) was cheaper when first introduced. Then they raised their prices. SpaceX will do the same, because that's the way the business works--you buy in at a low cost, capture some customers, and then raise your rates. And the low prices currently cited by SpaceX don't include a number of things that are included in the prices for other launches. As always, the devil is lurking in the details.

The important thing is to not succumb to the hype. Remain skeptical of the claims that are being made by the advocates, and the people trying to make money.
 
Congrats to SpaceX on the successful launch and best of luck to them on a successful link up to the ISS.

Bob Clark
 
RGClark said:
Congrats to SpaceX on the successful launch and best of luck to them on a successful link up to the ISS.

Bob Clark

Congrats to SpaceX on the successful berthing of the Dragon spacecraft to the ISS.

Bob Clark
 
Arjen said:

Thanks for that. Here's a video of the splashdown:

Awesome Video of Dragon’s Descent and Landing.
Posted by Doug Messier on June 1, 2012, at 10:59 am in News
http://www.parabolicarc.com/2012/06/01/awesome-video-of-dragons-descent-and-landing/

In the photo of the Dragon in the water it looks like the one side where the parachute lines are attached is the one that is the most scorched. And from the video of the descent it looks like the lines are only attached at one point. This looks like it could be "single point failure" scenario. Is it common for other capsules to have all the parachute lines attached at only one point?


Bob Clark
 
In the photo of the Dragon in the water it looks like the one side where the parachute lines are attached is the one that is the most scorched. And from the video of the descent it looks like the lines are only attached at one point. This looks like it could be "single point failure" scenario. Is it common for other capsules to have all the parachute lines attached at only one point?


Bob Clark

There are some good close ups of the chute attachments in this video of the drop test article: http://vimeo.com/41871913

Looks like multiple attachments, close together. In any case, the aerospace business has been making single point attachments fault tolerant for decades. Pins within pins, multiple lugs around these pins, etc.
 
RGClark said:
This looks like it could be "single point failure" scenario. Is it common for other capsules to have all the parachute lines attached at only one point?

Yes. And no, it is not a single point failure. Not every system has dual redundancy or backup because it is not necessary or may cause other issues. There are not two hatches or two pressure vessels, in case of leaks. The attach fitting and cable are usually made more robust with higher factor of safety.
 
Hobbes said:
It's a pity they didn't have the capsule in sight at the moment of landing. Did they use the thrusters to soften the landing? Or is that going to be left for a later flight?

No, that is for a different version of the spacecraft. Not for the current logistics vehicle
 
Previously, I argued in favor of low cost manned lunar missions using a single launch of the 53 mT payload capacity Falcon Heavy launcher:

SpaceX Dragon spacecraft for low cost trips to the Moon.
http://exoscientist.blogspot.com/2012/05/spacex-dragon-spacecraft-for-low-cost.html

In a follow up post I'll show it can be done even cheaper than discussed there using smaller, currently available upper stages. This might allow manned lunar flights at three orders of magnitude cheaper cost than the estimated $100 billion total cost of the Constellation program, at least for single missions.
Note also the Falcon Heavy would also allow Bigelow-style space hotels to be transported to the lunar surface thus allowing long term stays on the Moon, also at much reduced costs than earlier estimates. I'll write about this as well.
However, for supporters of the SLS, in another follow up post I'll show a single launch of the interim 70 mT version could carry the Orion capsule to a lunar landing and back using Centaur-style Earth departure and landing stages. This argument depends on the ca. 20 to 1 mass ratio ULA suggests can be produced by switching to lightweight aluminum-lithium alloys.
This is important because it means rather than the interim 70 mT just making test flights, it can actually be used for manned flights to the Moon.
Note that Lori Garver at the recent AIAA meeting said the SLS will indeed be used to make manned flights to the Moon:

NASA's Garver lists moon as goal for astronauts against Obama space policy.
LORI GARVER SEPTEMBER 11, 2012 BY: MARK WHITTINGTON
“The truth is, we have an ambitious series of deep space destinations we plan to explore, and are hard at work developing the hardware - and the technologies - to get us there.
“In fact, we just recently delivered a comprehensive report to Congress outlining our destinations which makes clear that SLS will go way beyond low Earth orbit to explore the expansive space around the Earth-moon system, near-Earth asteroids, the moon, and ultimately, Mars. Let me say that again: We're going back to the moon, attempting a first-ever mission to send humans to an asteroid and actively developing a plan to take Americans to Mars.“
http://www.examiner.com/article/nasa-s-garver-lists-moon-as-goal-for-astronauts-against-obama-space-policy

NASA is considering lunar flyby missions with the interim 70 mT version of the SLS:

NASA Weighs Early Deep-Space Tests With Orion.
By Frank Morring, Jr.
September 13, 2012
Planners in NASA’s human exploration and operations (HEO)
missions directorate are studying whether it would be possible and
worthwhile to expand the first three planned tests of the Orion
multipurpose crew vehicle, including the first flight with a crew, to
evaluate the capsule’s performance beyond low Earth orbit.
Architecture studies of potential deep-space missions using Orion also
are being used to consider ways to use the big capsule to collect data
on how it would perform beyond low Earth orbit, in lunar flyaround
like the Apollo 8 mission, and perhaps early flights to the Earth-Moon
lagrangian points under discussion as destinations where human
explorers could prepare for missions to asteroids and eventually Mars
and its moons, according to HEO Associate Administrator William
Gerstenmaier.
http://m.aviationweek.com/Article.aspx?id=/article-xml/asd_09_13_2012_p05-01-494215.xml&p=1

Then rather then just doing a flyby mission with the 70 mT SLS version or waiting until 2030 when the full 130 mT version will launch, a full manned lander mission can be launched sometime after 2017 when the 70 mT version becomes available:

Space Launch System.
http://en.wikipedia.org/wiki/Space_Launch_System#Program_costs

Interestingly then, since the Falcon Heavy can also do such single launch Moon missions, the next Moon race may be between the commercial space providers and NASA.


Bob Clark
 
RGClark said:
In a follow up post I'll show it can be done even cheaper than discussed there using smaller, currently available upper stages. This might allow manned lunar flights at three orders of magnitude cheaper cost than the estimated $100 billion total cost of the Constellation program, at least for single missions.

When you do that, can you also list the qualifications and background of the team you have that is putting together this information? Can you also share with us your cost models and indicate how well they have performed over time on other space programs?
 
Previously, I argued in favor of low cost manned lunar missions using a single launch of the 53 mT payload capacity Falcon Heavy launcher:
Coincidence, Chrysler serv had the same capacity.
 
The interim, Block 0 SLS will use three SSME's, a standard sized ET, i.e., no tank stretch, and 4 segment SRB's. This will have a ca. 70 metric ton payload capability. The DIRECT teams version has similar payload capability:

http://www.directlauncher.org/documents/Baseball_Cards/J130-41.4000.08100_CLV_100x100nmi_29.0deg_090606.jpg

In reports on the Block 0 SLS, NASA discussed the option of it using 4 or 5 segment SRB's as if it were no big deal. But I was surprised when I looked at the 5 segment version on the DIRECT teams site, that the payload jumped to ca. 95 metric tons:

http://www.directlauncher.org/documents/Baseball_Cards/J130H-41.5000.08100_CLV_30x100nmi_29.0deg_090608.jpg

A jump in payload of 25,000 kg is a big deal. It's the difference in payload for instance between the 105 metric ton Block I version, and the 130 metric ton Block II version of the SLS. It would also mean the Block 0 with 5-segment SRB's would be close to the "magic" 100 metric ton payload number. And with just the interim upper stage, it would certainly exceed that.
Judging by this Chris Bergin article, we would expect the 5 segment SRB's to be ready by the 2017 first flight of the Block 0 SLS:

ATK and NASA ground test their SLS-bound five segment motor.
September 8th, 2011 by Chris Bergin
As far as ATK’s role in SLS, documentation (L2) shows the Utah-based company have proposed a Firm Fixed Price (FFP) contract for 10 boosters, available between 2012-2015, whilst noting available assets that can support up to 11 SLS missions prior to asset depletion in 2020.
http://www.nasaspaceflight.com/2011/09/atk-and-nasa-ground-test-five-segment-motor/

With a 70 metric ton limit I could just get the Orion to the lunar surface and back, but with very slender margins. But with a 95 metric ton limit it's doable with quite a bit of leeway.


Bob Clark
 
It is generally acknowledged that the SLS is based on the DIRECT teams "Jupiter" launcher. Then their respective launchers closely mirror each other in their payload capabilities for versions with similar components.
The Block 0 SLS was initially planned to have a 70 mT payload capability, as mirrored by the corresponding DIRECT launcher. However, the current plan is to go directly to a Block 1 launcher, scheduled for a 2017 flight date. This will use 5-segment SRB's instead of the regular 4-segment ones planned for the Block 0. However, if you look at the DIRECT teams 5-segment version of their Jupiter rocket it has nearly a 95 mT capability. Moreover, NASA wants to give the Block 1 an additional SSME core engine and stretch the tank. Then it will have even greater payload than the 95 mT of the corresponding DIRECT teams launcher.
So NASA is still using the 70 mT payload number of the Block 0 in discussing this initial flight of the SLS when the actual payload capability will be 95+ mT.
I think NASA should be more clear about what the actual capabilities of that first version of the SLS to fly will actually be. Saying it will do 70 metric tons to LEO is misleading as to what that first version can actually do.
According to the reports that first version to fly will even have an interim cryogenic upper stage, and at quite low cost by the reports if the Delta IV derived one is used. Presumably, this will improve the LEO capability, perhaps to the 100 to 105 metric ton range.
A launch capability this high raises the possibility of even doing lander missions not just lunar flyby's. This is important because it means we will have the capability of doing lunar lander missions not just in 2030 when the full SLS comes on line but just in 5 years.
This becomes even more important when you realize the necessary stages, the Centaurs, already exist to make the Earth departure/lander stages. ULA has written numerous reports on markedly reducing boiloff in the Centaurs so that we can consider that to be well understood, and essentially solved.
It has been complained that the SLS has no mission. NASA being direct, so to speak, about what the actual capabilities of that first version of the SLS to fly will make clear that the SLS does have an important mission, and in the very near term and at (comparatively) low cost: Return to the Moon.


Bob Clark
 
blackstar said:
RGClark said:
In a follow up post I'll show it can be done even cheaper than discussed there using smaller, currently available upper stages. This might allow manned lunar flights at three orders of magnitude cheaper cost than the estimated $100 billion total cost of the Constellation program, at least for single missions.

When you do that, can you also list the qualifications and background of the team you have that is putting together this information? Can you also share with us your cost models and indicate how well they have performed over time on other space programs?

That calculation I mentioned for a ca. $100 million manned flight to the Moon is my own. It's based on the calculation on my blog that I linked to in post #62 in this thread. The version discussed there uses the Falcon Heavy at a ca. $120 million launch cost plus two Centaur stages at a $30 million cost each, for a total $180 million. There will be development cost there for combining the two Centaurs into a single vehicle and for adding landing legs. But this will be spread out over several vehicles and will be comparatively low cost compared to the total cost of the vehicle.
For the $100 million Moon vehicle, I'll argue in the upcoming blog post that we can make a half-size capsule compared to the Dragon to only carry three crew instead of seven. We can then use half-sized Centaur-style upper stages. Based on the costs of similar, currently existing stages at half-size of the Centaurs, these will cost about half that of the Centaurs. We may assume also that based on mass, the launch cost using the Falcon Heavy will be about half that of the full sized case.
This will put the total cost under $100 million. Again there will be development cost in integrating the two half-sized Centaurs together and adding landing legs, but again these will be comparatively low cost.

However, aside from this also interesting as I mentioned above is that what has been referred to as just the interim SLS, instead of having a payload capacity of only 70 mT will probably be above 100 mT when you include the interim cryogenic upper stage. This means all cryogenic Earth departure/lander stages can land the entire Orion capsule, no expensive Altair lander required, on the Moon and at quite healthy margins.


Bob Clark
 
blackstar said:
You seem to be engaged in a random conversation with voices in your head. Who the heck are you responding to?

When I started this thread I was quite interested in the fact that you could do low cost manned, lunar lander missions with just a single Falcon Heavy launch. This is quite controversial. Even SpaceX thinks it will take two launches.
However, when looking up info on the SLS I was truly startled to find that the first launch of the vehicle, just 5 years from now, instead of just having a payload capacity of only 70 mT will actually have one of 100+ mT. This is majorly important because knowledgeable NASA observers have said it will take a 100 mT launcher to do a manned flight to the Moon. So just using conservative, known estimates for the mass of the upper/lander stages of such a vehicle we will have the capability to do manned lunar lander flights by 2017.
Since the, currently existing, cryogenic upper stages cost just a small fraction of the cost of the SLS launcher NASA will also have the funds for such missions.


Bob Clark
 
RGClark said:
That calculation I mentioned for a ca. $100 million manned flight to the Moon is my own. It's based on the calculation on my blog that I linked to in post #62 in this thread.

Oh, so you were replying to something that you wrote two weeks earlier.

That makes perfect sense.
 
so you were replying to something that you wrote two weeks earlier

Then, RGClark, what is the point of posting on a forum if this for discussing with yourself and not the other members ? :eek: ::)
I suggest you create your own forum of which you will be the only member - perhaps under different pseudos so that you will have the illusion to speak with various people. What do you think ?
 
Please stop personal attack. Remember the forum rules.
 
blackstar said:
RGClark said:
That calculation I mentioned for a ca. $100 million manned flight to the Moon is my own. It's based on the calculation on my blog that I linked to in post #62 in this thread.

Oh, so you were replying to something that you wrote two weeks earlier.

That makes perfect sense.

I have been wracking my brain for the last two weeks looking at various combinations and architectures for getting cryogenic upper stages to fit within a 70 mT limit while being able to carry a 9 mT Orion capsule to the Moon and back. I had to look up several different articles on cutting mass to the Centaurs. I was looking up also various different trajectories for cutting the required delta-V for the flight in order to reduce the propellant load, from direct descent to direct ascent and various combinations of them.
I was finally able to find a way to do it but the margins were so slender I knew NASA would never go for it. So I wanted then to reduce the mass of the SLS core stage, which uses a shuttle ET derived tank. So I needed to know what was the dry mass of the core stage. I found that NASA had not put up, at least nowhere I found, the dry mass of the core stage. However, I knew that the SLS was derived from the DIRECT teams "Jupiter" launcher. So I looked on their web site for the corresponding Jupiter launchers.
That's when I found that all that time I spent trying to squeeze every last bit of performance out of the Centaurs and every last bit of weight saving out of them had been unnecessary. Since the SLS closely mirrors the DIRECT teams launchers, the actual payload for the first version of the SLS to actually launch will be 100 mT or more.
You could deduce this from what NASA has been saying, though they have been saying it in a confusing and contradictory fashion. The Block 0, the one that really would only have a 70 mT payload capacity, was originally planned to be launched first in 2016. However, NASA chose to forego that and go directly to the Block 1. But NASA has already announced the Block 1 will have a payload capability of 105 mT. However, it would require the 5-segment SRB's to be ready when it launches in 2017.
So I think the reason why NASA continues to give the payload for the first launch as only 70 mT is because of some uncertainty in whether or not the 5-segment will be ready in 2017. Then I think a better way NASA could describe the capabilities for this first launch is to say it will be the Block 1 at a 100+ mT capability using 5-segment SRB's. However, if the 5-segment is not ready by then, then we have a fall back option to use the 4-segment SRB's at a 70 mT capability.


Blackstar, I'm a fan of your aerospace articles. You must have some contacts at NASA that know the inside scoop on the SLS. Perhaps you can ask if this first launch of the SLS will actually have a 100+ mT capability assuming the 5-segment SRB's are ready. And if that is the case, if they know that studies going back to the 90's show this is sufficient for manned lunar landing flights if using all cryogenic upper stages.
Note also that the SLS having this capability of a manned lunar landing by just 2017 would also have an important influence in securing continued funding for it.


Bob Clark
 
Orionblamblam said:
RGClark said:
I have been wracking my brain for the last two weeks...

I ask this in all seriousness: does it ever occur to you that nobody takes you seriously?

I see you have over 4,800 posts to the forum. You likely are aware of members of the forum that are in NASA or the industry and are connected to the SLS. You can ask them what will likely be the launch capabilities of the Block 1 SLS due to launch in 2017 if the 5-segment SRB's do have the predicted performance increase over the usual 4-segment SRB's.
Another way to think about it is the Block 0 just using 4-segment SRB's, 3 SSME's, and no tank stretch was predicted to have a 70 mT capability. According to Ed Kyle's page on the SLS, the tank stretch for the Block 1 is about 33% above the usual ET size and the 5-segment SRB's have about 25% more propellant and thrust than the 4-segments:

Space Launch Report - Space Launch System Data Sheet.
http://spacelaunchreport.com/sls0.html

Moreover, you are using 33% greater core stage thrust in going to 4 engines instead of three. It doesn't seem reasonable that the payload capability will stay the same when you are increasing the propellant load and engine thrust to that degree. And Ed Kyle on that page estimates the actual payload of the Block 1 as about 95 mT.

In regards to a ca. 100 mT launcher carrying a manned lander mission, this is often the estimated size given by experts in the field of the required launcher. Note that Elon Musk in saying it would require two launches of the Falcon Heavy is essentially saying this.
And here's an article by Robert Zubrin where he states this:

The New Sputnik.
Mon, 13 December, 2010 Submitted by: Robert Zubrin | in commentaries.
Using hydrogen/oxygen propulsion for all in-space flight elements, a transportation system based on a 100-ton-to-orbit booster could land 20 tons on the Moon, which is more than enough to deliver a crew capsule to the lunar surface together with a fully fueled Earth return stage capable of propelling it home.
http://www.spacenews.com/commentaries/101213-blog-new-sputnik.html


Bob Clark
 
As follow-up to the blog post on using the Dragon on a single launch of the Falcon Heavy for lunar missions, I found the "Early Lunar Access" proposal of the early 90's was using a similar architecture as what I was proposing, also using all cryogenic space stages:

SpaceX Dragon spacecraft for low cost trips to the Moon, page 2: Comparison to 'Early Lunar Access'.
http://exoscientist.blogspot.com/2012/10/spacex-dragon-spacecraft-for-low-cost.html


Bob Clark
 
Argues the SLS as early as 2017 can be used to launch manned lunar lander missions:

SLS for Return to the Moon by the 50th Anniversary of Apollo 11.
http://exoscientist.blogspot.com/2012/10/sls-for-return-to-moon-by-50th.html


Bob Clark
 
RGClark said:
Argues the SLS as early as 2017 can be used to launch manned lunar lander missions:

SLS for Return to the Moon by the 50th Anniversary of Apollo 11.
http://exoscientist.blogspot.com/2012/10/sls-for-return-to-moon-by-50th.html


Bob Clark

Again, what did this have to do with Spacex?

You are just spamming this forum by providing a linking to your blog about an unrelated topic. Not to mention that you still don't know what you are talking about and you are wrong in your blog.
 

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