Yet another Mars architecture

Spaniard · 2015-07-24 01:48:14

RobS wrote:

This is a fascinating 100-page report that was just announced by the National Space Society today

I think that, in a arquitecture of multiple launches, it will be helpfull to have some ion space tugs with robot arms.

This spacecrafts could move huge mass efficiently between orbits, and, from time to time, some of the cargo could add a fuel depot for the own tug.

This should reduce a lot the cost of mass cargo between Moon or Mars and Earth

Moon could put mass on Earth orbit with a rail launcher easily and with these tugs the cargo could be put on LEO using low fuel.

Manned mission are different. Time is important and ion thrusters are too slow. But cargo for life support for a base could be moved by this tugs.

RobS · 2015-07-24 20:30:36

Stephen Petranek has a new book out called How We'll Live on Mars. It starts with Werner von Braun and his Mars plans, noting pointedly that von Braun viewed the moon as useless wasteland and never wanted to go there. A lot of the book focuses on Space X and includes a lot of information Petronek got in an interview with Musk. In it, he says Musk said the "Mars Colonial Transport" would have a first stage and a second stage and a mass 2 to 3 times that of the Saturn V, so that means it would be able to put roughly 250 tonnes in low Earth orbit. There, the second stage would refuel and would fire again to serve as a trans-Mars injection stage. The second stage would land on the Martian surface, apparently with the human habitation module. Apparently Musk said that the MCT had two stages for Earth launch and one for Martian launch. That may explain the confusion over whether the Mars Colonial Transporter refers to the passenger module or the launch rocket; it refers to both. The reusable second stage would be just about the right size for a return to Earth for use to send more people to Mars.

Petronek also asked Musk about the idea of settling 80,000 people on Mars and Musk said no, he meant 80,000 people going to Mars every 2 years! At $500,000 per person, that would be about 1/4 of a percent of the GDP of the US, or 40 billion dollars. Musk said that any serious effort to settle Mars deserved 1/4 to 1/2 of a percent of the GDP of the US, and 80,000 people was roughly 1 per 100,000 inhabitants of the Earth, assuming 8 billion people in a few more decades. They would go in ships carrying 100 at a time, so that would be 800 ships launched into orbit and awaiting the right month or so to head out for Mars, presumably able to rescue each other in the process.

louis · 2015-07-25 19:34:34

Thanks RobS -

Fascinating stuff. Makes Musk's plans a little clearer!

If it was anyone else than Musk one would be highly sceptical about such claims - but I have always been a Musk believer and think he will win through on his plans.

RobS wrote:

Stephen Petranek has a new book out called How We'll Live on Mars. It starts with Werner von Braun and his Mars plans, noting pointedly that von Braun viewed the moon as useless wasteland and never wanted to go there. A lot of the book focuses on Space X and includes a lot of information Petronek got in an interview with Musk. In it, he says Musk said the "Mars Colonial Transport" would have a first stage and a second stage and a mass 2 to 3 times that of the Saturn V, so that means it would be able to put roughly 250 tonnes in low Earth orbit. There, the second stage would refuel and would fire again to serve as a trans-Mars injection stage. The second stage would land on the Martian surface, apparently with the human habitation module. Apparently Musk said that the MCT had two stages for Earth launch and one for Martian launch. That may explain the confusion over whether the Mars Colonial Transporter refers to the passenger module or the launch rocket; it refers to both. The reusable second stage would be just about the right size for a return to Earth for use to send more people to Mars.
Petronek also asked Musk about the idea of settling 80,000 people on Mars and Musk said no, he meant 80,000 people going to Mars every 2 years! At $500,000 per person, that would be about 1/4 of a percent of the GDP of the US, or 40 billion dollars. Musk said that any serious effort to settle Mars deserved 1/4 to 1/2 of a percent of the GDP of the US, and 80,000 people was roughly 1 per 100,000 inhabitants of the Earth, assuming 8 billion people in a few more decades. They would go in ships carrying 100 at a time, so that would be 800 ships launched into orbit and awaiting the right month or so to head out for Mars, presumably able to rescue each other in the process.

louis · 2015-07-25 19:37:10

I'd like to add that if the USA devoted that much to Mars, they would be receiving huge income from the rest of the world (from other space agencies who would want to buy into the project, from sale of Mars regolith and so on). I say "so on" because the real limiting factor is NASA's absurd dislike of commercialisation.

SpaceNut · 2015-07-26 11:32:35

The other space agencies other than Nasa have no real large sum of extra capital to buy into anything and you see that even with the ISS....next to Russia there is little put forth by them.

RGClark · 2015-09-05 18:22:55

Falcon Heavy might match first version of SLS.

SpaceX has said the improvement of the performance with the Falcon 9 v1.2 would be about 30%. With the upgraded engines and densified propellants applied to the Falcon Heavy, the max payload of the FH to LEO could then also be increased from 53 metric tons to 70 mT.
If so, then the FH, at a ca. $100 million cost, could match the capability of the initial Block I version of the gigadollar SLS at 70 metric tons to LEO.

First Falcon Heavy Launch Scheduled for Spring.
by Jeff Foust — September 2, 2015
http://spacenews.com/first-falcon-heavy … or-spring/

Actually, I'm dubious of the cited payload of the Block I SLS as 70 mT. I think it's likely to be closer to 90 mT:

SLS for Return to the Moon by the 50th Anniversary of Apollo 11, page 5: A 90+ metric ton first launch of the SLS.
http://exoscientist.blogspot.com/2013/0 … -50th.html

Bob Clark

Tom Kalbfus · 2015-09-06 08:43:49

Since were discussing Mars architecture here What about the Mars architecture in this movie?

https://video.search.yahoo.com/search/v … tion=click

RobertDyck · 2015-09-06 11:20:12

It doesn't load for me, but that's the official trailer for the movie "The Martian". YouTube copy here:
https://www.youtube.com/watch?v=Ue4PCI0NamI

That starts with an Opposition class mission, also known as a "Short Stay" mission. Here are some typical trajectories from NASA:
Short-Stay:

Long-Stay minimum energy:

Long-Stay fast transit:

Comparison of the three:

The mission architecture in Mars Direct is a compromise between "Long-Stay minimum energy" and "Long-stay fast transit". I have proposed cutting total mission time down so the first mission returns to Earth before the second mission departs. So the conjunction of Earth with Mars limits total mission days. That is also a compromise between "Long-Stay minimum energy" and "Long-stay fast transit", very similar to Mars Direct but a slightly shorter surface stay.

Short-Stay shown in this movie is one that NASA always talked about before Mars Direct. (insert insulting expletive here) I thought that NASA gave up on Short-Stay, starting with the NASA Design Reference Mission (DRM). Why bring it back?
------

Next problem with this architecture: size of everything. The Interplanetary Transit Vehicle (ITV) that I talk about is the top floor (top story) of a Mars Direct hab. That has an 8.4 metre diameter outside diameter, exactly matching the SLS core stage and Exploration Upper Stage (EUS). Plus Dragon as a lifeboat, and ADEPT heat shield for aerocapture. This would be spun for artificial gravity. Sticking with the idea from Mars Direct, using the spent TMI stage as a counterweight with a tether connecting them. GW Johnson talks about a rigid connection between hab and counterweight, resulting in a baton shape. But this movie shows a HUGE ship with four rotating hab modules connected to a non-rotating core. How big is this thing? And look at the interior volume: if a US navy ship were this big, how many crew members? Is it fair to compare this thing to a frigate, US Navy Oliver Hazard Perry-class frigate has a compliment of 176. Or should I compare this to a Cyclone-class patrol ship: only 55 metre length, 4 officers plus 24 enlisted men. The movie ship has a crew of 6.

------

Then there's the Mars base. For a 30 or 31 day stay, how gigantic is this thing? The one room that the lead character converts to a garden to grow food is as large as the entire Mars Direct habitat. And you can see tunnels leading off to other parts of the base. How big is this Mars base?

Last edited by RobertDyck (2015-09-06 12:20:24)

RobertDyck · 2015-09-06 12:01:25

The Hermes ITV also has a cockpit like the flight deck of the Space Shuttle, complete with two deck living space (flight deck + mid-deck) and windshield for the flight deck. This zero-G Shuttle-style module has two cupolas, and two cylindrical sections attached to the nose. These two nose sections are off-axis, creating a torque when attempting to use engines for thrust. What are the nose sections for?

GW Johnson · 2015-09-06 12:07:51

R G Clark re launch prices post 656 above:

Hi Bob --

The numbers I have seen correspond to a 53-ton payload to LEO for a F-H launch price of $128M in 2012 dollars. That's $2.42M/ton (metric), if flying "full".

For SLS, it depends on whose launch price estimates you believe (ranging from $500M to $1000M), and which configuration you look at: 70 ton, 100 ton, or 130 ton to LEO. The numbers range from $4M/ton to $14M/ton flying "full".

The only attractions I see to use SLS are the larger tonnages in a single launch, and the larger shroud diameter (8 m vs 5 m). With orbital assembly by docking plus inflatables about to enter the market, those advantages seem to be becoming less important, excepting only Apollo-style one mission-one launch scenarios, which inherently border on flag-and-footprints stunts.

GW

Tom Kalbfus · 2015-09-06 12:20:45

I'd say the Interplanetary Transit vehicle looks to be of similar size to the ISS, and it would probably be built the same way, using the SLS, we could probably get the components into orbit with fewer trips than the Shuttle, the ship is also reusable, in the book, the ship was meant to be used for all the Ares Missions, not just the one where the astronaut got stranded on Mars. I bet under your plan, you throw away the transit vehicle after every mission, and launch a new one for each mission as in Apollo, am I right?

RobertDyck wrote:

It doesn't load for me, but that's the official trailer for the movie "The Martian". YouTube copy here:
https://www.youtube.com/watch?v=Ue4PCI0NamI
That starts with an Opposition class mission, also known as a "Short Stay" mission. Here are some typical trajectories from NASA:
Short-Stay:
http://nssdc.gsfc.nasa.gov/planetary/ma … rtstay.gif
Long-Stay minimum energy:
http://nssdc.gsfc.nasa.gov/planetary/ma … ngstay.gif
Long-Stay fast transit:
http://nssdc.gsfc.nasa.gov/planetary/ma … strans.gif
Comparison of the three:
http://nssdc.gsfc.nasa.gov/planetary/ma … ompare.gif
The mission architecture in Mars Direct is a compromise between "Long-Stay minimum energy" and "Long-stay fast transit". I have proposed cutting total mission time down so the first mission returns to Earth before the second mission departs. So the conjunction of Earth with Mars limits total mission days. That is also a compromise between "Long-Stay minimum energy" and "Long-stay fast transit", very similar to Mars Direct but a slightly shorter surface stay.
Short-Stay shown in this movie is one that NASA always talked about before Mars Direct. (insert insulting expletive here) I thought that NASA gave up on Short-Stay, starting with the NASA Design Reference Mission (DRM). Why bring it back?
------
Next problem with this architecture: size of everything. The Interplanetary Transit Vehicle (ITV) that I talk about is the top floor (top story) of a Mars Direct hab. That has an 8.4 metre diameter outside diameter, exactly matching the SLS core stage and Exploration Upper Stage (EUS). Plus Dragon as a lifeboat, and ADEPT heat shield for aerocapture. This would be spun for artificial gravity. Sticking with the idea from Mars Direct, using the spent TMI stage as a counterweight with a tether connecting them. GW Johnson talks about a rigid connection between hab and counterweight, resulting in a baton shape. But this movie shows a HUGE ship with four rotating hab modules connected to a non-rotating core. How big is this thing? And look at the interior volume: if a US navy ship were this big, how many crew members? Is it fair to compare this thing to a frigate, US Navy Oliver Hazard Perry-class frigate has a compliment of 176. Or should I compare this to a Cyclone-class patrol ship: only 55 metre length, 4 officers plus 24 enlisted men. The movie ship has a crew of 6.
http://cdn.arstechnica.net/wp-content/uploads/2015/06/martianteaser-hermes-640x269.jpg
http://chapters.marssociety.org/winnipe … Window.jpg
Then there's the Mars base. For a 30 or 31 day stay, how gigantic is this thing? The one room that the lead character converts to a garden to grow food is as large as the entire Mars Direct habitat. And you can see tunnels leading off to other parts of the base. How big is this Mars base?
http://i.dailymail.co.uk/i/pix/2015/06/ … 466248.jpg

How would this movie been different if the Author used Mars Direct instead of what was used in the Movie?

Last edited by Tom Kalbfus (2015-09-06 12:25:06)

RobertDyck · 2015-09-06 12:32:43

Tom Kalbfus wrote:

I'd say the Interplanetary Transit vehicle looks to be of similar size to the ISS, and it would probably be built the same way, using the SLS, we could probably get the components into orbit with fewer trips than the Shuttle, the ship is also reusable, in the book, the ship was meant to be used for all the Ares Missions, not just the one where the astronaut got stranded on Mars. I bet under your plan, you throw away the transit vehicle after every mission, and launch a new one for each mission as in Apollo, am I right?

Nope. Under my plan I reuse the transit vehicle. I would like the transit vehicle to be used for 12 trips, once every time Mars aligns with Earth so once every 26 months. That means 26 years before it's thrown away. Shuttle first launched in 1981, last launch 2011. That's 30 years. So a reusable ITV that is docked to ISS for service between missions should last 26 years.

However, the TMI propulsion stage is thrown away each mission. It's designed so if a reusable stage is invented, and if propellant production at Mars is developed, and if a means to deliver that propellant to the ITV in Mars orbit is built, then the expendable propulsion stage can be replaced with a reusable one. A lot of ifs. If current policies are followed, I expect someone will develop a new vehicle with reusable propulsion. Expect a fully reusable ship to replace my ITV after 26 years.

But yea, the movie ITV is as large as ISS. In fact it has 3 ISS solar arrays, plus radiators. ISS itself has 4.

Tom Kalbfus · 2015-09-06 16:15:36

Why do you suppose the Author of this book used this particular mission plan? Was it a story reason, or did he actually believe that this was the best way to go to Mars? Mars direct is designed to last until the replacement crew arrives, What if Mark Watney got stranded in a Mars Direct Mission where the rest of the crew left in an emergency, so he was all alone on the planet?

You know another thing, at least their Interplanetary Spaceship wasn't as big as the Starship Nostromo from the Movie Alien, the film was made by the same people who made Alien after all.

Last edited by Tom Kalbfus (2015-09-06 16:20:27)

RobertDyck · 2015-09-06 16:52:48

Mars Direct has a hab and ERV. It also has an inflatable greenhouse. If the crew left early with one man left behind, he would have everything necessary. And wouldn't have to wait 4 years. Let's see, 180 days to Mars, then 500 days on the surface, then 180 days back. Planets align once every 26 months; that's about 790 days. If the crew left on time but without him, the next launch window would be 110 days later. So the next hab would land 180 days later, or 290 days after the first crew left. The ERV takes a slower route, about 8.5 months instead of 6 months. Sending a hab without an ERV preceding it is risky, but with a crew member on Mars, would be justified. The only question is whether to land the hab unmanned for supplies only, or send a committed rescue crew. With a pre-established dedicated greenhouse, and a hab designed to support 4 crew for 500 days, supporting 1 astronaut for 290 days more is highly plausible. Perhaps one reason the author chose not to use Mars Direct is because it wouldn't be so dramatic.

Last edited by RobertDyck (2015-09-08 08:20:15)

Tom Kalbfus · 2015-09-06 18:27:10

RobertDyck wrote:

Mars Direct has a hab and ERV. It also has an inflatable greenhouse. If the crew left early with one man left behind, he would have everything necessary. And wouldn't have to wait 4 years. Let's see, 180 days to Mars, then 500 days pm the surface, then 180 days back. Planets align once every 26 months; that's about 790 days. If the crew left on time but without him, the next launch window would be 110 days later. So the next hab would land 180 days later, or 290 days after the first crew left. The ERV takes a slower route, about 8.5 months instead of 6 months. Sending a hab without an ERV preceding it is risky, but with a crew member on Mars, would be justified. The only question is whether to land the hab unmanned for supplies only, or send a committed rescue crew. With a pre-established dedicated greenhouse, and a hab designed to support 4 crew for 500 days, supporting 1 astronaut for 290 days more is highly plausible. Perhaps one reason the author chose not to use Mars Direct is because it wouldn't be so dramatic.

It is good for our cause to have a realistic Mars movie for once, and not "Robinson Crusoe on Mars" There are so many Mars Movies that are just too "Hollywood" they have to have those rubber suited aliens, or Surprise Mars has breathable air and they just didn't know it, so when the astronaut's faceplate breaks open and the actor gets to show his face, the air is breathable, all on account or runaway nanotechnology left by the last mission, but there is something living under the Martian sand that wants to kill him! Which movie was that? I remember a Movie called "Mission to Mars" or was it called "The Red Planet" with a premise similar to that. Most Mars movies are horrible, I think "The Martian" is going to be the exception to that. Maybe if we have an interesting movie with a plausible premise and a plot to keep the audience glued to its seat, this would be helpful to generating interest for an actual Mars Mission. I don't think "John Carter of Mars" was particularly helpful either. We need interest in the actual Mars, not some fictional Mars with monsters on it. I think The Martian is much in the tradition of the Movie "Gravity" as it depicts more of what can really happen in space, not the usual sci fi tripe.

RobertDyck · 2015-09-06 19:31:00

Tom Kalbfus wrote:

Movies that are just too "Hollywood" ... or Surprise Mars has breathable air and they just didn't know it, so when the astronaut's faceplate breaks open and the actor gets to show his face, the air is breathable, all on account or runaway nanotechnology left by the last mission, but there is something living under the Martian sand that wants to kill him! Which movie was that? I remember a Movie called "Mission to Mars" or was it called "The Red Planet" with a premise similar to that.

That was "The Red Planet". A movie called "Mission to Mars" came out the same year. "Mission to Mars" had a Mars Direct hab as the first mission, with an astronaut stranded on Mars. He wasn't expected to live, but they found him still alive, surviving by growing vegetables in the greenhouse. However, the second mission was a giant spacecraft, and the the pyramid on Mars was an actual pyramid covered in dirt with relics of space aliens inside.

Last edited by RobertDyck (2015-09-06 19:32:40)

RobertDyck · 2015-09-06 19:37:09

I saw an interview with SpaceX president Gwynne Shotwell who said she was considering building a new Falcon 9 using the stretched core from the strap-ons of Falcon Heavy. What lift capacity would that have? And I'm thinking to ISS orbit, so again we can use ISS as construction shack for orbital assembly of a Mars ship.

SpaceNut · 2015-09-06 21:01:04

The dreams and hopes of mars are in the numbers. The days, the size and cost to support a crew are all numbers that can be calculated but still they are all dependant of the mission all going as expected as planned.

Tom Kalbfus · 2015-09-08 07:09:25

SpaceNut wrote:

The dreams and hopes of mars are in the numbers. The days, the size and cost to support a crew are all numbers that can be calculated but still they are all dependant of the mission all going as expected as planned.

You mean getting the costs down through technological innovation, don't you? Getting to Mars should be made inexpensive, perhaps billions of dollars should be spent doing that, its not a matter of rockets so much as a matter of making those rockets. If you can assemble an SLS stage with fewer workers than what it took to build a similarly capable Saturn V stage, that would make getting to Mars less expensive!

RobertDyck · 2015-09-08 08:15:03

You want to revive Saturn V? First remember the first stage was built at the Michoud Assembly Facility, later convert to make Shuttle ET, and now manufacturing core stages for SLS. So that doesn't change the building or which contactor runs it. And tooling has been changed several times, you would have to re-tool to go back to Saturn V stages.

Second and third stages of Saturn V used the J-2 engine. The latest updated version is the J-2X engine. That's been indefinitely mothballed. The reason was salesmen for the RL-10 engine convinced the powers that be to buy their engine. Actually, numbers show an upper stage for SLS would have similar performance for the Moon or Mars, although dramatically reduced payload mass for LEO. And the stage based on RL-10 has significantly less propellant. That means lower cost for stage tanks and propellant to fill them. And the launch pad gantry doesn't have to be as high. That means SLS block 2B would incur less cost to modify the gantry from SLS block 1.

And engines for Saturn V first stage were F-1. The current updated version is F-1B. That engine is proposed for liquid boosters for SLS block 2B. That would be great! However, the powers that be have still not decided. Salesmen from ATK are still trying to push their advanced SRB that adds high explosive to the propellant for increase performance. Ok, yea, at the dilution ratio proposed RDX or HMX will burn as a rich oxidizer. But the advanced SRB would still have segments, ATK proposed going back to 4 like Shuttle. So again nothing but an O-ring separating even hotter solid rocket exhaust from the liquid hydrogen tank of the SLS core stage. And the advanced SRB casing will be composite instead of steel, to reduce weight. That containing even hotter solid rocket fuel combustion. I'm worried about burn-through. Does my bias for liquid rockets show? Tiny solids for medium variants of Atlas V or Delta IV are Ok because they're small and because the casing is one piece; no O-ring. I would like development of LRB using F-1B engines to start now. But reviving Saturn V would also require approving F-1B engines.

And the instrument unit for Saturn V used 1960s electronics. That would have to be completely redesigned with modern electronics. So it's far too late to revive Saturn V.

RobertDyck · 2015-09-08 08:27:20

Found a schedule for Mars launch windows. It assumes an 8.5 month transit, like Curiosity. But it gives an idea of launch times.
Cosmic Train Schedule
Interesting, the launch in 2016 would arrive in 2018. Launch windows open 780 days apart. It's a couple days different for each year. Mars has an elliptical orbit, so exact time depends on position in that orbit. But that means for the rescue scenario above, cut time until a rescue ship arrives by 10 days.

Tom Kalbfus · 2015-09-08 11:34:36

RobertDyck wrote:

You want to revive Saturn V? First remember the first stage was built at the Michoud Assembly Facility, later convert to make Shuttle ET, and now manufacturing core stages for SLS. So that doesn't change the building or which contactor runs it. And tooling has been changed several times, you would have to re-tool to go back to Saturn V stages.
Second and third stages of Saturn V used the J-2 engine. The latest updated version is the J-2X engine. That's been indefinitely mothballed. The reason was salesmen for the RL-10 engine convinced the powers that be to buy their engine. Actually, numbers show an upper stage for SLS would have similar performance for the Moon or Mars, although dramatically reduced payload mass for LEO. And the stage based on RL-10 has significantly less propellant. That means lower cost for stage tanks and propellant to fill them. And the launch pad gantry doesn't have to be as high. That means SLS block 2B would incur less cost to modify the gantry from SLS block 1.
And engines for Saturn V first stage were F-1. The current updated version is F-1B. That engine is proposed for liquid boosters for SLS block 2B. That would be great! However, the powers that be have still not decided. Salesmen from ATK are still trying to push their advanced SRB that adds high explosive to the propellant for increase performance. Ok, yea, at the dilution ratio proposed RDX or HMX will burn as a rich oxidizer. But the advanced SRB would still have segments, ATK proposed going back to 4 like Shuttle. So again nothing but an O-ring separating even hotter solid rocket exhaust from the liquid hydrogen tank of the SLS core stage. And the advanced SRB casing will be composite instead of steel, to reduce weight. That containing even hotter solid rocket fuel combustion. I'm worried about burn-through. Does my bias for liquid rockets show? Tiny solids for medium variants of Atlas V or Delta IV are Ok because they're small and because the casing is one piece; no O-ring. I would like development of LRB using F-1B engines to start now. But reviving Saturn V would also require approving F-1B engines.
And the instrument unit for Saturn V used 1960s electronics. That would have to be completely redesigned with modern electronics. So it's far too late to revive Saturn V.

The point is to automate the production of these boosters as much as possible, whatever they are, not paying as many salaries reduces the cost. Using one size fits all strategies may fit as well, See Falcon Heavy:
elon-musk-is-about-to-launch-the-heaviest-rocket-in-existence--and-yes-it-can-reach-mars.jpg
http://www.theverge.com/2015/9/6/927031 … pring-2016
The Falcon Heavy relies on putting three falcon rockets side by side to increase thrust and payload, the rocket engines the factories churn out turn out to be the same size.

Here are some larger members of the Falcon Family which might be relevant for Mars Exploration.

Last edited by Tom Kalbfus (2015-09-08 11:39:25)

RobertDyck · 2015-09-08 12:16:46

Tom Kalbfus wrote:

The point is to automate the production of these boosters as much as possible, whatever they are, not paying as many salaries reduces the cost. Using one size fits all strategies may fit as well, See Falcon Heavy:
...
The Falcon Heavy relies on putting three falcon rockets side by side to increase thrust and payload, the rocket engines the factories churn out turn out to be the same size.

They're already looking at that. SLS block 2 was supposed to have a core stage with 5 engines, block 1 would have 4. They cancelled the stage with 5 engines. And the upper stage would use J-2X engines: one for Moon or Mars, 2 or 3 for heavy lift to LEO. They cancelled that entire stage, replacing it with Exploration Upper Stage with 4 RL-10 engines. It can deliver just as much mass to distant destinations, but not nearly as much to LEO. One big advantage is the shorter propellant tank, meaning less modification to the service gantry. Assuming an Orion capsule is on top, difference in height of the capsule is not as much. Now there's the question of LRB. The only difference from SLS block 1 to 1B is replacing the Interim Upper Stage with Exploration Upper Stage. And again, Interim Upper Stage is the upper stage of a Delta IV. And the only difference from block 1B to 2B is replacing 5-segment SRBs with either Advanced SRBs or LRBs. (Please use LRBs.)

Then there's management issues. When Shuttle was flying, I spoke with several engineers who worked on it. They all told me they proposed changes to procedures or equipment that would reduce the amount of work necessary to process Shuttle for another flight. This would increase flight rate and reduce cost. They all report management told them no. The reason they were rejected was because it reduced cost. One engineer reported management said "You're taking bread from people's mouths." They all said management made similar statements, that reducing cost means less pay for contractor employees, and less profit for contractor shareholders.

When Bill Clinton was president, NASA tried to replace Shuttle with VentureStar. Many were surprised that Lockheed-Martin won the contract, after all they're one of the companies gouging NASA the most. For X-33, NASA put a clause in the contract stating any cost overrun had to be shared by the contractor. Then Lockheed-Martin made a last minute change to replace the solid wall composite propellant thank with a hollow wall. Test in the hanger failed. Everything else had been tested before X-33: composite tanks on DC-XA, lifting bodies had been studied extensively in the late '60s and early '70s, aerospike engine was a consideration for the original Shuttle. This tank change was the only new thing. So NASA activated that clause of the contract. Lockheed-Martin refused. Lawyers argued for two years, with no progress on X-33. Then George W. Bush got elected, and cancelled the whole thing.

SpaceX is reducing labour and automating as much as possible. Perhaps competition from them will give Old Space contractors enough a kick in the pants.

Tom Kalbfus wrote:

Here are some larger members of the Falcon Family which might be relevant for Mars Exploration.

Yea, I said the upper stage of Falcon X is wide enough for a self-launching module, one launched wet. And Falcon X Heavy is enough to launch Mars Direct: one for the ERV, one for the hab. But will it get built?

Hey! United Launch Alliance! Are you reading this? Either get the cost of SLS down or SpaceX will build Falcon X to replace it.

GW Johnson · 2015-09-08 14:11:24

Hi RobertDyck:

Don't be so afraid of solids. Solids have a real place right off the launch pad, or else so many boosters wouldn't be using them. Frontal thrust density with a solid is simply unbeatable by any conceivable liquid system, that's why. The safer abortable growth position for solid boosters is actually the abortable forms of hybrid technology (not all are). There simply aren't any big ones yet. Or else it would have already happened.

Every solid, even the all-one-piece-case solids on Atlas-V, have O-ring joints in the front end at the forward closure, and in the rear end, however the nozzle assembly is "tied" on. Typically, these have 1 (and only 1) O-ring, and I have never ever heard of a failure at the O-ring joints.

The SRB joints should have been 1 O-ring, but were not at NASA's insistence, out of their complete ignorance and inexperience with solids. 2 and 3 O-rings (as we saw in shuttle SRB's) actually increase the odds that a joint will leak. I have waxed eloquent about that idiocy on these forums before.

There's absolutely nothing wrong with solids done right. No JATO bottle ever downed the bomber or transport that it launched. And such things are cheap enough to throw away, at least until and unless recoverable liquid stages actually become available. I'll believe THAT when I actually see it, but we can always hope.

GW

RGClark · 2015-09-08 22:59:26

RobertDyck wrote:

I saw an interview with SpaceX president Gwynne Shotwell who said she was considering building a new Falcon 9 using the stretched core from the strap-ons of Falcon Heavy. What lift capacity would that have? And I'm thinking to ISS orbit, so again we can use ISS as construction shack for orbital assembly of a Mars ship.

Do you have a link for that? I thought the boosters had the same size as the F9 core.

Bob Clark

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#651 2015-07-24 01:48:14

Re: Yet another Mars architecture

#652 2015-07-24 20:30:36

Re: Yet another Mars architecture

#653 2015-07-25 19:34:34

Re: Yet another Mars architecture

#654 2015-07-25 19:37:10

Re: Yet another Mars architecture

#655 2015-07-26 11:32:35

Re: Yet another Mars architecture

#656 2015-09-05 18:22:55

Re: Yet another Mars architecture

#657 2015-09-06 08:43:49

Re: Yet another Mars architecture

#658 2015-09-06 11:20:12

Re: Yet another Mars architecture

#659 2015-09-06 12:01:25

Re: Yet another Mars architecture

#660 2015-09-06 12:07:51

Re: Yet another Mars architecture

#661 2015-09-06 12:20:45

Re: Yet another Mars architecture

#662 2015-09-06 12:32:43

Re: Yet another Mars architecture

#663 2015-09-06 16:15:36

Re: Yet another Mars architecture

#664 2015-09-06 16:52:48

Re: Yet another Mars architecture

#665 2015-09-06 18:27:10

Re: Yet another Mars architecture

#666 2015-09-06 19:31:00

Re: Yet another Mars architecture

#667 2015-09-06 19:37:09

Re: Yet another Mars architecture

#668 2015-09-06 21:01:04

Re: Yet another Mars architecture

#669 2015-09-08 07:09:25

Re: Yet another Mars architecture

#670 2015-09-08 08:15:03

Re: Yet another Mars architecture

#671 2015-09-08 08:27:20

Re: Yet another Mars architecture

#672 2015-09-08 11:34:36

Re: Yet another Mars architecture

#673 2015-09-08 12:16:46

Re: Yet another Mars architecture

#674 2015-09-08 14:11:24

Re: Yet another Mars architecture

#675 2015-09-08 22:59:26

Re: Yet another Mars architecture

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