Blue Origin Thread (merged)

[Lukaszenko]

10 hours ago, Northstar1989 said:

And on that note, it's extremely easy to plan an aerocapture to orbit anyways- you just aerocapture into an elliptical orbit and the raise your periapsis so there's no chance of re-entering instead of aerobraking on the next pass.  Aerobraking is easy so long as you're conservative and give yourself a good 20-30% margin for error (that is, you assume you'll slow down more than expected, and so make shallower passes).

Aerobraking is easy and done all the time, because you can always make a shallower pass. You don't even need heat shields. Aerocapture to orbit on the other hand has never been done, because you CAN'T always make a shallower pass, and you don't really know what's up with the atmosphere at the exact instant you want to use it.

Edited October 7, 2016 by Lukaszenko

[DerekL1963]

1 hour ago, CatastrophicFailure said:

No, it's not the most efficient approach but it's simple.

Simplicity has an efficiency all it's own...    I suspect his engineers have done the necessary trade studies and arrived at the same conclusion.

[insert_name]

1 hour ago, Lukaszenko said:

Aerobraking is easy and done all the time, because you can always make a shallower pass. You don't even need hear shields. Aerocapture to orbit on the other hand has never been done, because you CAN'T always make a shallower pass, and you don't really know what's up with the atmosphere at the exact instant you want to use it.

the Huygens probe areocaptured to a suborbital trajectory, as have other landers, it shouldn't be that hard. also, we have a space craft devoted primarily to studying the Martian atmosphere (maven)

[Northstar1989]

4 hours ago, KerbalSaver said:

I'm not quite understanding how sending a lander back and forth 10-12 times to unload a ship is more efficient if the landers have a lifetime of 12 uses. Isn't that basically 1 use? You would be sending a disposable lander with every ITS mission.

It's beneficial because you get the same function as a larger lander used once, but at a fraction the cost.  Reusability is, in simplest terms, a force-multiplier (to use this term in a logistics sense or like they do in the military)- it simply allows you to amortize the cost of a vehicle over multiple uses rather than needing to justify the cost with a single use.

Smaller landers can be re-used more times in a single mission, and have the benefit of redundancy- if one lander breaks down, you simply use the others more times.  Sure, there is a chance they ALL break down in a single mission, but if you make the reliability high enough that risk becomes negligible.  Even if you have 4 landers each only 90% reliable over 12 uses, and the odds of breakdown go up 10% for each lander that breaks (due to needing to use the others more), the odds of them ALL failing are only 0.1* 0.2* 0.3 * 0.4 = 0.0024, or 0.24%.  The ITS, in its current incarnation, faces a risk of losing all hands aboard in a catastrophic accident as well- and in that event it will be *much* worse than simply losing 2-4 people if a single lander fails in a way causing it to crash...

If an ITS launch costs an average of $63 million dollars after amortizing the construction and refueling costs over 12 launches (which is the figure that you get using Musk's figures of $140k a ton and a 450 ton payload), but a Falcon Heavy launch of a Mars lander with full reusability costs just $1.5 million (right now, a disposable F9H launch is priced at $90 million, but Musk thinks that reusability will ultimately bring down costs a "couple orders of magnitude" according to his ITS presentation...), and you need 4 such landers to ferry the ITS crew to the Martian surface, and using landers increases the payload of the ITS just 10%, then you save $6,300,000- $6,000,000, = $300,000 a mission.

If the cost of a fully-reusable F9H launch were $900k instead, and you increased payload capacity by 20% instead of 10%, then you'd have $9 million to play around with to build each set of 4 identical landers and still make a profit...  Amortize costs over 12 transfer-windows (the same period Musk is amortizing the cost of each ITS over) and you get $108 million to develop, build and fly 48 identical Mars landers for EACH Interplanetary Transport Ship built and flown (and Musk evisions THOUSANDS of them...)

 

Regards,

Northstar

Edited October 7, 2016 by Northstar1989

[DerekL1963]

46 minutes ago, Northstar1989 said:

It's beneficial because you get the same function as a larger lander used once, but at a fraction the cost.

The larger lander isn't used once - it's used multiple times over it's lifetime.

48 minutes ago, Northstar1989 said:

The ITS, in its current incarnation, faces a risk of losing all hands aboard in a catastrophic accident as well- and in that event it will be *much* worse than simply losing 2-4 people if a single lander fails in a way causing it to crash...

You fail to mention the risk inherent in docking. (Despite having it pointed out to you previously.)  Your lander could either significantly damage the ITS itself, or damage the ITS docking system such that any remaining people/cargo are stranded aboard.

[Northstar1989]

59 minutes ago, DerekL1963 said:

You fail to mention the risk inherent in docking. (Despite having it pointed out to you previously.)  Your lander could either significantly damage the ITS itself, or damage the ITS docking system such that any remaining people/cargo are stranded aboard.

The "risk inherent in docking" is quite low.  Especially when you have 2 or 3 (small) redundant docking ports so you can load/unload all the landers at once (if one becomes unusable you just use the others more).

For the record, how many times, exactly, has docking EVER resulted in the kind of catastrophic damage to a large spacecraft or station (the vessel itself- not just to its docking port such that it becomes unusable) you are talking about?  How many times in the past 20 years?

 

Regards,

Northstar

Edited October 7, 2016 by Northstar1989

[DerekL1963]

Just now, Northstar1989 said:

The "risk inherent in dockimg" is quite low.

"Low" is not nonexistent.  And when you start talking hundreds or thousands of dockings - even low risks start to loom large.  When you're planning a program, you have to consider such things.  You can't simply handwave away real problems that don't cast your plan in a positive light.
 

2 minutes ago, Northstar1989 said:

For the record, how many times, exactly, has docking EVER resulted in the kind of catastrophic damage to a large spacecraft or station you are talking about?

0.o  Progress M-34 caused serious damage.  Not that what did or did not happen in the past is in any way relevant.

[Northstar1989]

On Thursday, October 06, 2016 at 9:27 PM, DerekL1963 said:

The larger lander isn't used once - it's used multiple times over it's lifetime.

Ahh, but the point was to make a comparison to a reference that performs the same function as a small, reusable lander.  The point is that sending a small reusable lander that gets used many times in a short period and then retired is NOT the same as sending a disposable (and thus large, single-use) lander with each mission.  It's like exactly what the name implies- sending a reusable spacecraft- and the benefits are equal to, in fact GREATER than (because you use the lander many times in rapid succession, and there is thus less chance of the lander breaking while not being used) the re-usability of the ITS over a 24 year period...

Additionally, sending 3 or 4 small landers is NOT the same as sending a larger lander, regardless of reusability.  Smaller landers can be launched on lighter launch vehicles, and you get economies of scale from producing more of them (less overhead costs- as you can use the production facilities and staff closer to year-round) than you would larger landers.  Sending 4, 3, or even 1 or 2-man landers to Mars atop Falcon Heavy rockets nets you substantial economies of scale both in the production of the landers and in the production/re-use of the Falcon Heavy rockets.  Additionally, having a greater number of smaller landers and docking ports yields you significant redundancy and thus backups should something go wrong with one of them or a docking port...

 

On Thursday, October 06, 2016 at 7:21 PM, insert_name said:

the Huygens probe areocaptured to a suborbital trajectory, as have other landers, it shouldn't be that hard. also, we have a space craft devoted primarily to studying the Martian atmosphere (maven)

Indeed, though I wasn't suggesting aerobraking the Mars landers straight to a suborbital trajectory.

It's easier on the heatshield and the structure (fewer g's pulled during aerocapture) to aerobrake first to a very high elliptical orbit, then to a lower elliptical orbit, and then to a lower one still, and so on and so forth with many shallow aerobraking passes until your apoapsis is roughly where you want your orbital height or a little above it...

With a lander performing an unmanned aerocapture well ahead of the arrival of the crew, time spent aerobraking- much like time spent on a slower trajectory to Mars that requires less Delta-V or making lunar gravity-assists, shouldn't really be much of an issue, and allows to to send a larger lander to Mars using the same launch vehicle... (or the same lander with secondary payloads piggybacking, or on a smaller LV- you get the idea...)

 

Regards,

Northstar

 

On Thursday, October 06, 2016 at 5:23 PM, Lukaszenko said:

Aerobraking is easy and done all the time, because you can always make a shallower pass. You don't even need hear shields. Aerocapture to orbit on the other hand has never been done, because you CAN'T always make a shallower pass, and you don't really know what's up with the atmosphere at the exact instant you want to use it.

You don't need to aerocapture straight to a low orbit.  There's plenty of leeway between "aerocapture to a suborbital trajectory" and "aerocapture to a high elliptical orbit", and similarly plenty if altitudes you can aerocapture to intermediate to the two.  The obvious thing to do is just to aim for an elliptical orbit somewhere in the middle of the range in terms of velocity loss and carry some reserve fuel- so if you end up losing less or more velocity than expected you're still OK.

Why are you bringing up this subject anyways?  There is LITERALLY no difference between the problems the ITS will face in making an aerocapture and the problems a small reusable lander will face in making an aerocapture- in fact in many ways the lander has it easier, as it is smaller and has a lower ballistic coefficient- therefore you don't need to dip as low into the atmosphere to pull the same number of g's, and have more room for error in terms of having a hotter aerocapture than expected not causing the lander's heatshield to fail if it is made of the same stuff as the ITS' heatshield... (as the max temperatures of heatshields are in large part limited by the materials science at our disposal, so the ITS heatshield will necessarily have to operate closer to its limits due to the ITS' hotter aerocapture..)

Alternatively, this same reduction in re-entry heat due to lower ballistic coefficient allows you to use a thinner heatshield made of lighter materials on the lander if you want (to save mass/cost), and still be no closer to burning up than the ITS would be with a necessarily much thicker/heavier heatshield...

 

Regards,

Northstar

Edited October 7, 2016 by Northstar1989

[Mitchz95]

Is anyone else kind of concerned about the on-orbit refueling? We just got a pretty gnarly reminder of how dangerous that can be, and Amos-6 was just sitting on the pad with nobody nearby. If something like that were to happen to an ITS full of colonists in LEO... well, it wouldn't be pretty. And the debris could threaten any other spacecraft in LEO, including potentially dozens of other ITS ships that wouldn't be able to land or take evasive maneuvers.

It might be prudent to launch the ships with nobody on board, and use Dragons to send them up once they've been refueled for the voyage.

[Northstar1989]

1 hour ago, DerekL1963 said:

"Low" is not nonexistent.  And when you start talking hundreds or thousands of dockings - even low risks start to loom large.  When you're planning a program, you have to consider such things.  You can't simply handwave away real problems that don't cast your plan in a positive light.
 

0.o  Progress M-34 caused serious damage.  Not that what did or did not happen in the past is in any way relevant.

ANY risk "looms large" if you look at a large enough dataset.  By that logic we should never drive cars, or drink alcohol, or even walk outside.  Because *all* of those things carry substantial risks.

The past is important because it's often the best, and most accurate, predictor of the future.  We might be blowing certain risks out of proportion (as the Age of Sail shows we are with space exploration for people spending long periods of time together in cramped conditions), or conversely, be minimizing risks that are very real (as you are with the risk of the ENTIRE ITS burning up during re-entry Space Shuttle Columbia-style if you don't use a lander and just one sufficiently large section of thermal tile fails in the ITS heatshield).  The past is the empirical proof of things, not influenced by our assumption and biases (although these things still hurt or sbility to see it clearly).  Otherwise, without the data the past provides, you have to live in a fact-free zone...

 

Regards,

Northstar

Edited October 7, 2016 by Northstar1989

[CatastrophicFailure]

7 minutes ago, Mitchz95 said:

Is anyone else kind of concerned about the on-orbit refueling? We just got a pretty gnarly reminder of how dangerous that can be, and Amos-6 was just sitting on the pad with nobody nearby. If something like that were to happen to an ITS full of colonists in LEO... well, it wouldn't be pretty. And the debris could threaten any other spacecraft in LEO, including potentially dozens of other ITS ships that wouldn't be able to land or take evasive maneuvers.

It might be prudent to launch the ships with nobody on board, and use Dragons to send them up once they've been refueled for the voyage.

Orbital refueling has been going on for decades, Salyuts, Mir, ISS... and with stuff much nastier in a vacuum than methane & LOX.

[Northstar1989]

26 minutes ago, CatastrophicFailure said:

Orbital refueling has been going on for decades, Salyuts, Mir, ISS... and with stuff much nastier in a vacuum than methane & LOX.

Has it?  I'm only aware of a handful of such trials of orbital refueling, all conducted with hypergolics (which ARE nastier in vacuum as they combust if they simply come in contact with each other, but are not cryogenic- and thus MUCH less likely to have issues leading to an explosion/release in the first place...)

Anyways, the orbital refueling is clearly one of the riskier aspects of the mission architecture- and with the size of the tanker's fuel reserves potentially MUCH more dangerous than refueling from a small lander.  I'm all for sending the crew/cargo up in capsules after the refueling to avoid most of the risk in the first place...

This also has the benefit of allowing you to leave the ITS in LEO between Mars sortee's and save on ITS booster usage.  Sure, orbital refurbishment between missions will undoubtedly be expensive- but building and maintaining boosters the size needed to launch the ITS can't be cheap either, it improves safety, and we're eventually going to need to learn how to do on-orbit maintenance better and cheaper anyways if we're going to make a Mars colony a thing and expand our manned presence in space beyond Low Earth Orbit... (A Mars colonization effort will undoubtedly eventually lead to a more expanded presence elsewhere in the solar system as well...  Asteroid belt mining to provide the Mars colony with minerals that are rare or hard to get on Mars, anyone?)

 

Regards,

Northstar 

P.S.  Also, docking itself- not so risky. The accident with Progress/Mir apparently occurred because the Russians were experimenting with new, untested docking procedures that they themselves knew might be risky- and even then all that Progress did was break off a single solar panel and create a SMALK, SLOW leak in one of the Mir modules which the Russians easily contained by sealing off that module.  If that's all anyone can come up with, then the historical record shows that the actual facts substantiate docking really not being all that dangerous as long as you stick with tried-and-true docking protocols...

Edited October 7, 2016 by Northstar1989

[CatastrophicFailure]

10 minutes ago, Northstar1989 said:

Has it?  I'm only aware of a handful of such trials of orbital refueling

The "descent module" of every Progress is a fuel tank, specifically to refuel the space station's RCS & reboost thrusters.

[Rakaydos]

Northstar, I am confident that SpaceX will maintain their curently reveaed architecture. It's not as efficent, but it's cheaper to debug two and a half overbuilt vehicals (tanker/ship comminality makes testing easier) than build a finely tuned,  carefully optimised powerpoint rocket that doesnt even work for bad conjunctions. If your one lander has a reentry failure, your mothership is dead anyway, unable to fuel up to return to earth. It doesnt matter that SpaceX is risking the entire ship at once, because the end result is the same.

If anything, SpaceX might add a cycler "mothership" later in the architecture's life, the ITS ship being the "Simple lander" you crave.

An ITS body that expands into a bigelo space hotel.

Edited October 7, 2016 by Rakaydos

[Northstar1989]

On Thursday, October 06, 2016 at 4:40 PM, DerekL1963 said:

0.o  Since the colony has precisely zero need of specialists in space technology - why would there be a collection there of the most knowledgeable people?  And if they've spent their time working on colony engineering, their skills and knowledge about spacecraft engineering will be rusty, and they've probably never been spacecraft maintenance technicians to start with.  (That's an important distinction few grasp  because we're in the habit of misusing the term engineer - there's two specialties involved.)  And there's more involved than just people - there's also all the required support equipment and spare parts.  Precisely none of which makes any sense to duplicate [the terrestrial facilities] and send to Mars.

The colony itself wouldn't have need for spacecraft repair technicians right away- if not for the need to refurbish landers so you can use them more than 12 times in rapid succession-  but you have to remember, everyone, and I mean EVERYONE would travel to Mars in the furst place in a SPACECRAFT.  So it's highly likely SpaceX would make a special effort to recruit such experts with relevant skills for the journey to Mars, and offer them a discounted fare if they agreed to undergo some vessel-specific training and help keep the ITS in good repair during the journey.  It wouldn't be much of a leap from that to SpaceX incentivizing them to refurbish some of their landers as well... (perhaps with extra food and supplies in the cargo shipments)

 

Regards,

Northstar

 

On Thursday, October 06, 2016 at 11:50 PM, Rakaydos said:

Northstar, I am confident that SpaceX will maintain their curently reveaed architecture. It's not as efficent, but it's cheaper to debug two and a half overbuilt vehicals (tanker/ship comminality makes testing easier) than build a finely tuned,  carefully optimised powerpoint rocket that doesnt even work for bad conjunctions. If your one lander has a reentry failure, your mothership is dead anyway, unable to fuel up to return to earth. It doesnt matter that SpaceX is risking the entire ship at once, because the end result is the same.

If anything, SpaceX might add a cycler "mothership" later in the architecture's life, the ITS ship being the "Simple lander" you crave.

An ITS body that expands into a bigelo space hotel.

Reducing the Delta-V load doesn't cut into the rocket being "overbuilt".  All that really means is it has large safety margins- which you can still do in the same ratio to the niw-reduced Delta-V requirements thanks to usinga lander...

As for a lander failing, I'm getting tired of repeating this point over and over with nobody listening- thst's precisely why you build MULTIPLE, *small* landers.  You'd have probably 3 or 4 of them.  That way, the failure of any single lander (or even 2-3 landers) doesn't endanger the mission.  That's *not* something you can say about the failure of any single section of re-entry tiling on the ITS- the loss of even a SMALL section of thermal tiling can lead to the loss of the entire spacecraft, Space Shuttle Columbia-style.

By breaking up your payload into more than two dozen lander descents and multiple landers, you avoid putting all your eggs in one basket, so to speak.  Because in this case, one bad apple (or re-entry tile) will ruin the entire barrel (main spacecraft), so it's wise to place them in several smaller baskets (multiple small landers).

 

Regards,

Northstar

P.S.  the Columbia disaster would have been much less heartbreaking if the Shuttle had been smaller, with each launch carrying a smaller crew complement, for precisely the same reason- larger, heavier craft are much riskier when it comes to re-entry.

P.P. S.  This is ALSO a very good justification for going with a Cycler Architecture, and making use of many smaller interceptor ships light enough to launch each on a Falcon Heavy- that way you get the benefits of having a large communal vessel during the voyage to Mars, but still don't endanger the entire crew should one thermal tile fail during aerocapture...

Edited October 7, 2016 by Northstar1989

[Rakaydos]

You're right, nobody is listening.

Certiantly not SpaceX. And probably not you.

SpaceX is accepting a certian amount of risk to simplify their architecture. One ship on direct entry, refuel, and SSTE(arth) is simpler than a mothership nailing aerocapture-to-orbit through uncertian weather conditions, leaving living space and engines in orbit while people and cargo land, sending fuel up a dozen times, then repeating the process back at earth.

KISS Principle.

Keep It Simple Stupid.

[Northstar1989]

On Friday, October 07, 2016 at 0:19 AM, Rakaydos said:

You're right, nobody is listening.

Certiantly not SpaceX. And probably not you.

SpaceX is accepting a certian amount of risk to simplify their architecture. One ship on direct entry, refuel, and SSTE(arth) is simpler than a mothership nailing aerocapture-to-orbit through uncertian weather conditions, leaving living space and engines in orbit while people and cargo land, sending fuel up a dozen times, then repeating the process back at earth.

KISS Principle.

Keep It Simple Stupid.

Why do you keep bringing up aerocapture?  That's not a difference between SpaceX's current architecture, and an alternative one relying on a lander.  Both rely on aerocapture to orbit to an equal degree (the ITS aerocaprures to orbit at Mars, it diesn't make a direct descent- as it would be virtually impossible to target such a descent to land at *precisely* the location of the colony on the surface...)- only the lander architecture doesn't also require re-entry of the main vessel.

To reiterate, your assertion that the ITS would make a direct re-entry is factually incorrect.

 

On Thursday, October 06, 2016 at 4:56 PM, CatastrophicFailure said:

Watching all this banter back and forth, some of y'all are completely missing the point of Musk's vision, here. 

He wants to do this fast. 

Fast. As in, within his lifetime. Cuz he wants to go while he's still spry enough to make the trip. That means keeping to the age old engineering principal of KISS - keep it simple, stupid. What he and his engineers have hashed out here is incredibly simple: only three craft, one of which just returns to earth. No, it's not the most efficient approach but it's simple. They'll make up for some of that lost efficiency by taking advantage of economies of scale. Remember, he sees these things being mass produced by the thousands. 

Whether that comes to fruition or not is highly speculative at this point. So's the whole thing. So the best way to actually accomplish it fast is by staying simple. Stick to the plan, make operations routine. 

I agree that Musk is currently sticking with KISS.  That doesn't mean it's necessarily the right approach, or that he'll be able to stick with it as he bumps up against cold, hard reality.

For that matter, I'm not even sure it's a good thing Musk is going with a behemoth 42-engine monstrosity of a booster and an 100-man payload to match.  Once again, that's sticking all your eggs in one basket- and the larger your rocket the more components you have that can lead to a catastrophic launch failure and the loss of the entire vessel...

Musk might be better off cutting both his booster and payload down in size by maybe a quarter or a third, and taking advantage of the greater economies of scale that provides.  A fourth the payload on each rocket means 4 times the number of rockets launches for the same payload, and 4 times the launch-volume brings you a LOT closer to airport-like operations where you launch new rockets as quickly as you can stick them on the pad...  It also means MASSIVE economies of scale when it comes to manufacturing the rockets, and much easier transportation if the rockets to the launchpad (as smaller rockets are easier to handle).

Larger rockets are more efficient from a mass standpoint, but as Musk has said himself, fuel-consumption is a very small part of the total cost of launching a rocket.  Ground ops and manufacturing (which both benefit greatly from higher launch-volume) are a much larger piece of the pie when it comes to launch-costs...

 

Once again, real life isn't KSP (I always go with larger rockets in KSP- due to the very mass-savings I mentioned earlier and the lack of any benefit to higher launch-volume in the game).  In real life, you're much better off with a whole lot of smaller rockets than a single large rocket 99% of the time...

 

Regards,

Northstar

Edited October 7, 2016 by Northstar1989

[DerekL1963]

2 hours ago, Northstar1989 said:

The colony itself wouldn't have need for spacecraft repair technicians right away- if not for the need to refurbish landers so you can use them more than 12 times in rapid succession-  but you have to remember, everyone, and I mean EVERYONE would travel to Mars in the furst place in a SPACECRAFT.  So it's highly likely SpaceX would make a special effort to recruit such experts with relevant skills for the journey to Mars, and offer them a discounted fare if they agreed to undergo some vessel-specific training and help keep the ITS in good repair during the journey.  It wouldn't be much of a leap from that to SpaceX incentivizing them to refurbish some of their landers as well... (perhaps with extra food and supplies in the cargo shipments)

0.o  Why would SpaceX make an effort to recruit spacecraft experts for the colony - when those are exactly the kind of expert not needed by the colony?  And it doesn't matter what kinds of skills or incentives offered - after any significant span of doing everything but spacecraft maintenance, they aren't going to be much good at the job.   This isn't shade tree mechanic stuff, it's a collection of highly specialized skills and knowledge .
 

3 hours ago, Northstar1989 said:

Ahh, but the point was to make a comparison to a reference that performs the same function as a small, reusable lander.  The point is that sending a small reusable lander that gets used many times in a short period and then retired is NOT the same as sending a disposable (and thus large, single-use) lander with each mission.

Since nobody is talking about sending a disposable lander for each mission, I'm not at all sure what orifice you pulled that straw man from.  Your scheme increases the number of (Earth) launches, cruise phases, Mars orbital insertions, landings, ascents, docking, cargo handling, fuel transfer, etc...  It increases the overall complexity by a significant margin.  That changes the risk equations, almost certainly for the worse, as sure as the sun is going to rise tomorrow.  It's just as simple as that.

There's more to engineering than just adding up the dollar signs.
 

3 hours ago, Northstar1989 said:

 We might be blowing certain risks out of proportion (as the Age of Sail shows we are with space exploration for people spending long periods of time together in cramped conditions)

0.o  Yes, because we're the same people we were in the Age of Sail.  We all grew up in cramped homes and cramped cities. or as peasants on the farm we wanted to get the heck away from, and...  Oh. wait.  We're not the same people.  We don't have the same experiences or social backgrounds.
 

3 hours ago, Northstar1989 said:

The past is the empirical proof of things

The past is an empirical proof of what happened in the past.  No more, no less.

[Northstar1989]

2 hours ago, DerekL1963 said:

0.o  Why would SpaceX make an effort to recruit spacecraft experts for the colony - when those are exactly the kind of expert not needed by the colony?  And it doesn't matter what kinds of skills or incentives offered - after any significant span of doing everything but spacecraft maintenance, they aren't going to be much good at the job.   This isn't shade tree mechanic stuff, it's a collection of highly specialized skills and knowledge .
 

Since nobody is talking about sending a disposable lander for each mission, I'm not at all sure what orifice you pulled that straw man from.  Your scheme increases the number of (Earth) launches, cruise phases, Mars orbital insertions, landings, ascents, docking, cargo handling, fuel transfer, etc...

Space X would make an effort to recruit spaceshop efforts because they're useful for the journey to the colony.  I already said that- and I find your wilfully ignoring my points and treating them as if I never said them highly rude and disrespectful.  As for keeping skills sharp, the technicians should have plenty of practice refurbishing Mars landers,once they reach Mars...

In that same vein, as I already said a larger number of smaller launches are more economical than a smaller number of larger launches- and smaller spacecraft are also safer during re-entry/landing.  A reusable lander increases the payload capacity of the ITS- a point I also already made before- thus substututing ITS launches with a much larger number of Falcon Heavy lander launches...  The total number of landings, takeoffs, etc is a poor measure of mission cost- and the mass savings and shift to a higher volume of smaller launches greatly outweighs this in reducing costs...

 

 

Edited October 7, 2016 by Northstar1989

[Nefrums]

Wonder if there will be weather complications to the restorations of the launchpads and/or investigation of the incident in the near future...

[Gkirmathal]

4 hours ago, Northstar1989 said:

Reducing the Delta-V load doesn't cut into the rocket being "overbuilt".  All that really means is it has large safety margins- which you can still do in the same ratio to the niw-reduced Delta-V requirements thanks to usinga lander...

As for a lander failing, I'm getting tired of repeating this point over and over with nobody listening- thst's precisely why you build MULTIPLE, *small* landers.  You'd have probably 3 or 4 of them.  That way, the failure of any single lander (or even 2-3 landers) doesn't endanger the mission.  That's *not* something you can say about the failure of any single section of re-entry tiling on the ITS- the loss of even a SMALL section of thermal tiling can lead to the loss of the entire spacecraft, Space Shuttle Columbia-style.

<snip>

I fully agree with you.

In an ideal world one would have several reusable LMO ships on Mars, that resupply a main vessel in LMO orbit. This to limit chance when  failures occur. Like you mention.

I think that eventually this will be the way it is going to work! But it will take several iterations of going to Mars (by who ever is going), whereby each iteration lays the foundations to make the idea's you lay eventually possible.

SpaceX now is rather constrained with what can be done, constrained financially I mean. They had to make choices so that Musk's idea would tick ALL the boxes within what is currently feasible. That means having to sacrifice on idea's (maybe you local LMO lander) for the very near  mission future, until more can be done as the price goes down. Take the current reuse of the F9 as example: if they accomplish that the price to orbit will go down drastically.

So what I think will happen: first they do it "as simple as possible" (current ITS) and over several missions they build the foundations on Mars to make possible: the unique reusable Mars LMO crafts, which would enable the refuel and resupplying of ITS ships in Mars low orbit.

 

For all the rest. I hope my writing the above can get together the people here trying to over voice each others ideas with ego. Cause you all are right! But fail to accept and place each others arguments in a correct time frame.

Edited October 7, 2016 by Gkirmathal

[Northstar1989]

On Friday, October 07, 2016 at 2:33 AM, DerekL1963 said:

Your scheme increases the number of (Earth) launches, cruise phases, Mars orbital insertions, landings, ascents, docking, cargo handling, fuel transfer, etc...  It increases the overall complexity by a significant margin.  That changes the risk equations, almost certainly for the worse, as sure as the sun is going to rise tomorrow.  It's just as simple as that.

There's more to engineering than just adding up the dollar signs.
 

0.o  Yes, because we're the same people we were in the Age of Sail.  We all grew up in cramped homes and cramped cities. or as peasants on the farm we wanted to get the heck away from, and...  Oh. wait.  We're not the same people.  We don't have the same experiences or social backgrounds.
 

The past is an empirical proof of what happened in the past.  No more, no less.

Risk equations are probability times consequence.  For instance a 1% chance of losing a million dollars is a much larger risk than a 10% chance of losing 10 dollars.  There is a much larger chance of something going wrong with the lander architecture (say a bad docking causing a tiny hull breach near one of the dicking ports, or one of the landers becoming inoperable), but the consequences are much less for most such failures.

The overall risk is less because, for example, losing one of four redundant landers (and 2-3 crew members with it) in a crash due to a landing computer failure is not nearly so bad as losing the entire ITS due to a couple of the thermal tiles failing in a repeat of the Columbia disaster.  Putting all your eggs in different baskets increases your chances of losing an egg or two- but greatly decreases your chances of losing ALL your eggs...

 

As for social conditions in the Age of Sail, yes they were different- but human nature is the same.  What's more, you drastically mistake the makeup of the migrant population to America early in its history.  The majority of migrants were not peasants, but middle-class merchants: because they were the only people who could afford the trip (before the spread of indentured servitude and slavery) but still had enough to gain to risk the voyage.  Well, except for a few nobles who fled Europe due to suffering religious persecution, like my ancestors on my mother's side (I'll avoid saying more on their reasons because the mods are watching), who were French nobility.

Your statement that the "the past is proof of what happened in the past, nothing more" is a nearly perfect paraphrase of the famous "history is bunk" line.  And like that line, you couldn't possibly be more wrong.  Those who do not learn from history are doomed to repeat it.  The same mistakes.  The same irrational fears- and ignoring of the real dangers...

 

Regards,

Northstar

 

On Friday, October 07, 2016 at 5:02 AM, Gkirmathal said:

I fully agree with you.

In an ideal world one would have several reusable LMO ships on Mars, that resupply a main vessel in LMO orbit. This to limit chance when  failures occur. Like you mention.

I think that eventually this will be the way it is going to work! But it will take several iterations of going to Mars (by who ever is going), whereby each iteration lays the foundations to make the idea's you lay eventually possible.

SpaceX now is rather constrained with what can be done, constrained financially I mean. They had to make choices so that Musk's idea would tick ALL the boxes within what is currently feasible. That means having to sacrifice on idea's (maybe you local LMO lander) for the very near  mission future, until more can be done as the price goes down. Take the current reuse of the F9 as example: if they accomplish that the price to orbit will go down drastically.

So what I think will happen: first they do it "as simple as possible" (current ITS) and over several missions they build the foundations on Mars to make possible: the unique reusable Mars LMO crafts, which would enable the refuel and resupplying of in orbit ITS ships.

 

I hope my writing the above can get together the people here trying to over voice each others ego with theyre ideas. Cause you all are right but fail to accept each others argument in a correct timeframe.

I agree that Musk is trying to keep it simple and R&D costs low.  But I do believe that to be a VERY bad idea.  Part of the reason that we've never gone to Mars is not because there were no simple ideas- it was because nobody was willing to make the large investments necessary to make it economical with more complex ones (like reusable launch stages!)

You would think Musk of all people would understand this, what with his being one of key figures in landing orbital launch stages back on Earth for the first time in history.  Without that INVESTMENT, a Mars colonization effort would never be remotely feasible.  But it's clear Musk hasn't learned the correct lesson from this- you have to be willing to take on lots of difficult challenges in order to accomplish anything worthwhile.

 The simple ITS plan Musk proposed is the easy road, not the hard one, at this point.  He-s already developed the ability to land launch stages, and he's going to run with that as far as it will take him.  But sadly, I fear that won't be quite enough- the current ITS plan will probably turn out to be somewhat more expensive to operate than it appears on paper, and I fear it will likely prove just a *bit* too expensive to get the kind of large-scale buy-in Musk needs and is hoping for... (a reusable lander would save money going forward, after the R&D costs were sunk- and might just make the difference between "too expensive" and "pricey but worth it" Mars tickets for many people...)

Instead of charging ahead, I sincerely believe Musk needs to lay a few more foundations and work on developing lander technology and building experience with interplanetary missions on a smaller scale before he attempts his Mars plan.

Which should be fine- even at SpaceX, rockets never come in on-schedule.  The Falcon Heavy was supposed to be flying years ago, for instance.  His Mars Colonial Teansporter booster will probably face similar delays.  So he should take his time to practice.  In my opinion, making Red Dragon landings and starting work on a reusable lander with some test vehicles here on Earth (and maybe at the Moon) would be an excellent way for Musk to cut his teeth on interplanetary missions and designing for them while his team works out all the technical issues with the ITS/MCT.

NASA was planning on a Moon-first strategy under Constellation for a reason, and while I feel that may have been a bit too conservative an approach, Musk would be wise to develop something smaller like a reusable lander he could send (unmanned) to Luna or Mars to gain experience with interplanetary missions before he builds an ITS and sends it to Mars...

 

Regards,

Northstar

[Gkirmathal]

@Northstar1989

Yes I think you are correct, but I also think Musk is fully aware of this and that he is limited in what he can currently accomplish financially. And that makes it a rather Catch-22 situation for them when designing anything. Sacrifices to have to be made

The ITS design shown last week, seems to me, a compromise between what is currently financial possible for SpaceX in the coming two decades and what is technically possible. That is why I think Musk initially chose the easy road.

Maybe RedDragon will add to their current design idea's, maybe it will not. We don't know yet. Might be fully possible that they conclude after RedDragon, they really need an extra LMO only system with ITS. We don't know yet.

Also agree on the need to lay some more initial foundations, although think of it, you have a 'small' budget with an uncertain global economical future. What would you do, extend R&D time with the risk of the whole program coming to a halt due to future economics going bad. Or, design a system now, current ITS plans, which can be build within a foreseeable time frame and with the current economical situation, with the current tech.

As much as I would personally ALSO, like you, want to have separate lander systems for Mars LO/LEO/Moon. I have to give in that currently it would make it too complex to design, for ONE company, within the time frame Musk wants to accomplish it. Like I said, maybe RedDragon will add to their plans.

About the Moon, IMO it would be more possible within 4 years to design something around Falcon Heavy. But I think the Chinese will beat the West to it.

As for the heated discussion you have with Derek, I really think you are both correct. Only your idea lays about 20 years in the future And that is not bad! We need to think and be able to discuss about any possibility and not be harsh about it. Every idea has it's place in time

 

Edited October 7, 2016 by Gkirmathal
typo's

[Technical Ben]

Bare in mind. Elon is not planning on sending anyone back. So a single shot lander for Mars only is the way they are going. The re-use lander would only work if done with a cycler system, giving a re-use lander for Mars only. We are not going to be returning that to earth.

Edited October 7, 2016 by Technical Ben

[Nibb31]

Northstar, I think you really have to let it go.

Musk's space program is Musk's space program. He's been working at it for years, employing thousands of bright people to think up the mission architecture, and this is what he has come up with. It complies to his requirements, which are dictated by SpaceX's business plan, technological capability, and schedule. And it also has to look cool.

What it doesn't involve are cyclers, landers, and smaller vehicles with more frequent launches. You can discuss these things as much as you want, but those ideas are not part of Musk's vision, and nobody is going to make him throw away years of SpaceX studies and prototyping. His plan has plenty of flaws that make it pretty unrealistic for anyone who isn't a starry-eyed fanboy, but you're not going to change the basic architecture. Posting page after page of walls of text on the subject won't change his mind. I suggest that if you want to open a thread to discuss the Northstar Mars Colonization Architecture, you do so.

Edited October 7, 2016 by Nibb31