Alan Boyle has a story on the current state of play for realistic concepts, something that SLS-based scenarios are not.
38 thoughts on “An Alternate Vision For Mars Trips”
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Alan Boyle has a story on the current state of play for realistic concepts, something that SLS-based scenarios are not.
Comments are closed.
Another word for “vision” is plan.
Why do people persist in thinking we can centrally plan our way into space?
Economic expansion happens with people who are interested in doing things that can be done now, not after the next successful five year plan.
I wouldn’t say “realistic.” John Strickland still wants a super-heavy lifter (in addition to propellant depots) — but a reusable one. I’ve been unable to make him understand that a giant reusable rocket that flies only one or twice a year will be expensive to operate, as well as develop.
He also suffers from the typical “new space” fantasy of believing that he will get to be the central planner, and NASA will implement the plan exactly the way he wants, with no changes and no interference from Congress, the White House, or NASA managers. How this miracle will happen, he never explains.
Please stop projecting your fantasies onto NewSpace.
Thanks, Trent. Spot on.
Yawn. Wake me when “New Space” does something besides throwing $700 beer parties and stealing credit for other people’s work.
Speaking of fantasies, I suggest you take a close look at the chairman-for-life, who still runs the organization after 25 years, and the rest of the leadership. When a product says “new and improved,” it’s a safe bet that it isn’t new.
Trent, I have no idea what you’re trying to say.
Are you denying that John Strickland is a member of “New Space”?
Are you denying that he wants a centrally planned space program? (I think you just said that yourself.)
Perhaps you don’t understand what you’re trying to say, either?
You seem to think every idiot with a megaphone is a doer.
I’d suggest this is more projection, but I know you actually are doing.
Perhaps if you concerned yourself less with identifying enemies you’d be better at identifying allies and get more done.
Trent, I still don’t know what you’re talking about, and I don’t think you do, either. I said quite clearly that “New Space” isn’t doing anything except throwing expensive drinking parties. From that, you conclude that I think they’re “doers”???
” I said quite clearly that “New Space” isn’t doing anything except throwing expensive drinking parties. From that, you conclude that I think they’re “doers”???”
Maybe as much as the Vikings were doers.
Economic expansion happens with people who are interested in doing things
Trent, you have a real talent at expressing what I consider to be foundational truth. Just the thing to knock down the house of cards that are many peoples beliefs.
Those people all have different ideas (which should compete) about doing things which is how you overcome the fragility of plans that the article talks about. Lansdorp plan has a fragility I posted about almost two weeks ago and referenced this article…
“If you have a Falcon Heavy, and you have a Dragon, and you have a Bigelow module, then all of a sudden, life gets interesting,” Pittman told NBC News. “It changes the whole equation here.”
Well yeah.
I believe the natural way we get to depots is first demonstrating fuel transfer which in itself expands our capabilities before we ‘centrally’ plan depots.
No plan survives reality.
“I believe the natural way we get to depots is first demonstrating fuel transfer”
Propellant transfer was demonstrated on a Space Shuttle mission almost 30 years.
But Ed, you know Shuttle doesn’t count in the NewSpace world, it would disprove the narrative that it was a huge failure 🙂
BTW its amazing how many folks forget fuel transfer is routine on the ISS. The Progress routinely transfers fuel to the ISS so its able to keep its orbit.
Unless you count restarting RL-10s, we’ve never demonstrated transfer of cryogenic propellants, just storables.
Rand,
Yes, the DMSP did demonstrate that as you state.
http://www.ulalaunch.com/site/docs/publications/SuccessfulFlightDemonstrationConductedbytheAirForceandUnitedLaunchAllianceWillEnhanceSpaceTransportation_.pdf
But you are also assuming that cryogenic fuels will be the best option for deep space operation simply because they work best for Earth launch. Yes, they have advantages in terms of power but given the storage issues of cryogenics “storable” propellents might actually be the better bet for deep space missions. And lets not forget the wild cards of ion and plasma propulsion systems.
30 years ago? So is it common, safe and standardized today? Because that’s what I’m talking about. Can anybody buy and sell fuel in orbit?
Ken,
No, because although it was an interesting experiment there was no market for it. Technology only advances rapidly when a viable market exists for its demand.
The problem with the comsat market is by the time they would benefit the satellites have already reached their accounting lifespan (been depreciated down to zero) and are technologically out of date. That is why its a better investment for firms to launch a replacement and move the existing one into a scape orbit than fix it.
You are absolutely right about the need for a market. That’s what a ship needing fuel in LEO would do.
“I believe the natural way we get to depots is first demonstrating fuel transfer which in itself expands our capabilities before we ‘centrally’ plan depots.”
I believe best way is to use fuel depots.
It’s unlikely someone launching one satellite, will make a fuel depot.
You need a entity that launches many satellites.
So I would say to get fuel depots, you need a spaceport, that wants fuel depots.
Or a space agency that wants fuel depots.
So competitive spaceports might lead to fuel depots.
Or we have get NASA to use fuel depots.
What I what recommend is simplest a cheapest fuel depot.
Though I think think a fuel depot which stored LOX is simple enough.
LOX is “universally used”, LOX is most massive component of rocket fuel
whether it’s LH&LOX or Kerosene & LOX.
But I think LOX depot favors LH&LOX, as LOX is more massive ratio
of mass difference.
So take Saturn V upper stage:
“The S-IVB carried 73,280 liters (19,359 U.S. gallons) of LOX, massing 87,200 kg (192,243 lbs). It carried 252,750 liters (66,770 U.S. gallons) of LH2, massing 18,000 kg (39,683 lbs). Empty weight was 9,559 kg (20,000 lb)”
Dry mass: 9,559 kg and LH: 18,000 kg.
So totals 28,000 kg with the part LOX being 87,200 kg.
So you didn’t need to lift as much of the LOX, existing rockets could lift this stage-
Falcon Heavy could lift it if 1/4 full of LOX.
So with falcon Heavy or any other launcher, one fill depot with could hold 80 tons of LOX.
Then Falcon Heavy could lift a large LH&LOX stage which needed to refuel with 80 tons
of LOX. Which effectively changes the Falcon Heavy from 53 ton to LEO, to a 53 +80 ton
launch vehicle: 133 ton to LEO.
So make fuel depot which can hold 80 tons of LOX. And make entire depot weigh, say
120 ton or so. Have depot move to the launched payload it will refuel, and have depot
do the docking. So rocket payload shows up somewhat close to depot, and then depot
does the rest.
So a spaceport can with it’s depot, can existentially double any rocket which launching at it’s launch site. And it would transform the SLS 70 ton rocket into 150 ton rocket.
Now how much is NASA going to spend to upgrade the 70 ton rocket [assuming it launches in 2017]
to 130 ton rocket. And could a LOX depot, cost as much as doing this?
But more important any rocket and any mission to beyond LEO, could use the depot.
And if this depot is made and used, it will become standard way to get into space.
I see no reason why the LOX needs to stored in the depot for more than one month, unless a launch is scrubbed for a longer period. So you deliver the LOX with “on time delivery” with the amount needed [up to limit of what the depot can hold].
Once this is routine operation, then depots can evolve to store stuff other than LOX.
And the private sector can put depots at L-1 or Mars orbit.
gbaikie,
Let’s agree that we start with LOX.
I see no reason why the LOX needs to stored in the depot for more than one month
I see no reason to limit duration or mass. A ship, depending on its mass and Isp may need more than 1000 mt of LOX to have enough delta V for its mission which may take some time to accumulate.
Now tell me the difference between and ship you can transfer fuel to and from, and a dedicated depot?
-I see no reason why the LOX needs to stored in the depot for more than one month-
“I see no reason to limit duration or mass. ”
Well I don’t know the specs, but depot which stored LOX had boil off 1%
per month, I don’t think that would be a problem.
But if it was 10% per month that would be a problem.
If was possible for it to be less 1% per month that is better.
And if passive thermal control was unable to do less than 5% per month,
one would probably be forced to use refrigeration.
Or perhaps refrigeration could be better option in any case.
“A ship, depending on its mass and Isp may need more than 1000 mt of LOX to have enough delta V for its mission which may take some time to accumulate.”
I think ship that needed 1000 mt of LOX, shouldn’t be in LEO. 🙂
Might be ok in Earth/Moon L-points for Fast trip to Mars.
It seem to me that being +50,000 km from the Moon and +200,000 km from Earth and month long “day”- rather than 90 min “day” would make it easier to passively cool cryogenic rocket fuel.
“Now tell me the difference between and ship you can transfer fuel to and from, and a dedicated depot?”
Well dedicated depot could have space arm- it seem like most ships would not need it. A depot could have refrigeration and/or significant thermal shielding whereas
one doesn’t need this as much with ships which transfer fuel. As ships can get there in days and depots could be there for weeks. One can pre-cool oxygen to 55 K and
it boils at 90 K- that could make it so ships need less thermal control.
A depot could have specialize pump to transfer propellant, it might transfer 100 ton
per hour, rather than minutes. Though it may not be pump.
And most ships don’t hold 80 tons of LOX.
But one have stage which was designed to be reused as depot. Hydrogen tanks are bigger and they could be flushed so as to be filled with LOX.
I think ship that needed 1000 mt of LOX, shouldn’t be in LEO
A BA330 is 23 mt. A ship based on it, with six crew and supplies could easily be 50 mt. Delta V to mars is 5700 m/s which depending on your Isp could require 5x to 10x the mass of the ship in fuel. If that fuel is coming from earth, LEO makes sense. You don’t need a refrigeration system. You need a parasol.
Good attempt but you missed the main difference. A ship can lease space on board providing a subsidy for your fuel lowering it’s cost to others. It provides a means for paying for the fuel.
You don’t have to give up the arm either. It stays in orbit to service the next ship. It’s part of a permanent tug that remains in LEO. Actually, it replaces the need for the depots to each have this feature (assuming one can be reached from another.)
Perhaps I should refer to the idea as tankers?
“A BA330 is 23 mt. A ship based on it, with six crew and supplies could easily be 50 mt. Delta V to mars is 5700 m/s which depending on your Isp could require 5x to 10x the mass of the ship in fuel. If that fuel is coming from earth, LEO makes sense.”
If fuel is coming from the Moon than it doesn’t make sense.
But why if coming from Earth does LEO make sense?
Why stage at LEO?
Why not directly go to Sun/Earth L-1 or 2. Or refuel in LEO then go to Sun/Earth L-1 or 2?
“This investigation focused on the use of a gateway station located at Earth-Moon Libration Point 2 for use in a manned mission to Mars. Such a station could be used to stage fuel and finalize systems and operations checks for an Earth-Mars transit vehicle, or other transit vehicle to deep space. Results show that, without detailed trajectory optimization, a case can be made for minimal increased costs associated with such a mission. Further investigation into lower energy trajectories from EM L2 to Mars could help drive down Δv requirements further, potentially below that of a direct transfer from Low Earth Orbit.”
http://ccar.colorado.edu/asen5050/projects/projects_2012/croteau/
They suggest doing gravity assist with the Moon as part of this, I recommend using Earth’s gravity well.
Either returning directly to Earth or bouncing off the Moon first and then returning to low perigee Earth, in which point rocket delta-v thrust is added giving additional Oberth effect to such thrust.
But I mainly thinking of getting to Mars in 3 month or less. If still seems to make sense if even traveling to Mars in 7 to 8 months.
Because, you have less station keeping and atmospheric drag [which become more significant the longer you are in LEO]. And it seems higher LEO orbits [+300 Km} to avoid this effect has addition delta-v penalty.
If stage at L-point, any launch site can reach it with no penalty [other inherent loss from higher latitude launch]. Europe or Sea launch can get to L-1 with least penalty, but you can also launch from Russia. Which means since one more competitors one can get better price. Or in space agencies, more international involvement. And one get more launches in terms of volume/capacity.
Plus you in the environment which is similar to what the Mars vehicle will traveling months of time traveling thru. It supposed to function in this type environment- it if problems, nearer to earth is better than at millions miles traveling away from Earth.
Why not directly go to [someplace other than LEO.]
If it makes sense, why not? However, if you accept my premise that you can lease time on the ship while it’s accumulating fuel then LEO is the place for it to be because it’s easier to get people to and from there than anyplace else.
OTOH, it may make sense to transfer fuel to a tanker in LEO then again to a ship at a Lagrange point so less fuel is required to get to their destination orbit.
It seems like a simple question. You just run the numbers.
Let’s say we do run the numbers (and thanks for that link.) We would be examining different scenarios and comparing them. One possibility…
1. We put a BA330 class ship in LEO dry.
2. We lease space on it to accumulate cash for the following steps.
3. We put an ion engine tanker in LEO with all the tools for fuel transfer (ship to ship or ship to/from depot.)
4. We buy fuel fuel from lowest cost provider to LEO.
5. We put a depot at EML2 which has a fuel capacity for our ship to go from there to mars orbit.
6. The tanker transfers fuel from our ship to the depot. Fuel continues to be bought by our ship in LEO.
7. We empty the ship of passengers but leave supplies needed for the mars mission and just enough fuel to get this to EML1.
8. Take the ship to EML1 where the tanker is waiting to transfer fuel from the depot to the ship.
9. Bring crew to EML1 and depart for mars using lunar gravity assist.
Compare the total cost of all aspects to other profiles. We might save half a billion dollars in fuel cost departing from EML1 than LEO which might not pay for the tanker and depot, but since the tanker and depot are fully reusable for a one time cost it makes sense anyway. If we assume following missions with new ships (or even just this one ship if it’s returned for further missions.)
In case it’s not clear: the tanker does not have the fuel capacity of the ship or the depot. This is why fuel is put on the ship in LEO rather than having the tanker take it straight to the depot. It could be that sometimes it could be taken straight to the depot but that’s a question of scheduling since the tanker has to be available for fuel ships arriving in LEO and it’s ion engines make a slow trip to and from the depot.
Let’s say we do run the numbers (and thanks for that link.) We would be examining different scenarios and comparing them. One possibility…
1. We put a BA330 class ship in LEO dry.
Ok. So that could put same inclination as ISS [using Proton launcher
or Falcon Heavy]. Or KSC inclination using Falcon Heavy].
It seems to me that BA330 would make good test payload for
Falcon Heavy- and therefore a relativity cheap launch costs.
And BA330 dry mass is around 20 tons.
*2. We lease space on it to accumulate cash for the following steps.*
It seems we it could make a profit. It’s done deal at that point.
But accumulate cash may mean mostly pay for interest on capital
cost [more or less profitable] or mostly pay for operational cost-
get more money per year than it”s yearly cost.
*3. We put an ion engine tanker in LEO with all the tools for fuel transfer (ship to ship or ship to/from depot.)*
ok.
I think Ion engine would work better in Cislunar space- as general note.
Earth’s blocking the Sun and in deep gravity well.
But If you could beam power from Earth, LEO has advantage in that aspect.
*4. We buy fuel fuel from lowest cost provider to LEO.*
This is private operation, right?
Then it seems that since NASA has been developing cargo launch capability to ISS, there is fair number potential launch providers which
available. One in sense would competing for demo type NASA launches,
which because time restriction and available NASA funding, I would agree
one could get low costs. There is advantage for a launch providers to launch as many launches per year that it is capable of doing. But whomever is paying the most, would tend to get priority.
The recent SpaceX Falcon 9 was a demo launch, and any modification to
rocket launcher would fit with the concept of demo launch. A different aspect is launches are delayed for various reason, and launch provider could plan to have excess launch capability in coming year, and this would cost less if provider depend on a way of using this excess launch. So sort
of like airline standby tickets.
*5. We put a depot at EML2 which has a fuel capacity for our ship to go from there to mars orbit.*
We don’t care about the Moon?
I think if had depot at EML2 and LEO, then someone would care about going to the Moon. If not NASA or US players, then Chinese and European
space agencies.
*6. The tanker transfers fuel from our ship to the depot. Fuel continues to be bought by our ship in LEO.*
If you had this, then some depot at lunar orbit, would like to use the ion transfer vehicle- ion would be more efficient for that leg of the route.
Or per day rent of Ion vehicle could higher [more profitable] for such a route.
*7. We empty the ship of passengers but leave supplies needed for the mars mission and just enough fuel to get this to EML1.*
I am getting the idea this is a SpaceX, Bigelow, [perhaps Space Adventure and/or Mars One] NASA enterprise?
Is LEO part of Mar One show?
Or is this mostly Elon Musk?
A few things, like ISS, the station need re-boost. Like ISS, all rocket fuel delivery will dispose/deorbit the Earth to LEO tanker into Earth atmosphere.
If one brings similar vehicles to EML1, it could useful as scrap.
Another aspect is, you are designing the BA330 so it’s suitable
for “deep space”. Why don’t start by placing in EML1?
What has more value for people, LEO or EML1.
Perhaps people would think LEO is better. Perhaps not.
Say there was a choice. One space station in LEO and
one in EML1. And assume the EML1 cost more [by some amount].
Assuming EML1 [but getting into the details of how much more]
which destination would most people want.
Or say Mars One was operating, which location would they want
for the show?
The question is simply which is preferable assuming the EML1
was more expensive, but since dollar amount is somewhat vague
anyhow- just assume it cost some amount more.
Mars One might want both. Maybe there first shows are LEO, but
would want EML1 as the “next level”.
So, this question is which is more “interesting”/desirable and/or useful.
Next question would how more would cost to ship people to EML1?
If the route is LEO, then to EML1, one also continue send Earth to LEO used fuel tanker, to burn up in Earth atmosphere. One could use more rocket fuel at LEO, thereby more of them.
But if sending a Dragon to LEO, refueling, than going to EML1 then using Dragon to return to Earth from EML1.
What difference in cost compared to going to LEO and returning to Earth from LEO.
So if per seat it’s 20 million to LEO, and 40 million to EML1 is somewhere around the difference?
you are also assuming that cryogenic fuels will be the best option for deep space operation simply because they work best for Earth launch.
You apparently have no idea whatsoever what I’m “assuming.” You’re the one doing the assuming.
Rand,
And as usual you dodge the question 🙂
There was no “question” for me to “dodge.” There was nothing but the statement of a foolish and false assumption about what I believe.
Rand,
So tells us, what do you believe?
I believe that cryogenic propellants will be useful in space, and I believe that the technology to handle and store them in that environment is immature. Any my belief has nothing to do with their performance in launch systems.
Rand is correct, cryo transfer depot style has never been done and is much harder than the uninitiated would expect. I doubt very many people have used a small cryo vacuum dewar (for cryo-optical experiments for example) but if you have, the transfer problem becomes readily apparent. Flash boiling wastes a lot of the cryogenic fluid and caused big pressure spikes, now add to that acquisition of a low surface tension fluid in zero-g.
Actually I wonder. When my mother was sick in the 1970’s she had liquid oxygen to make her breathing easier. They were quite new then. The system basically consisted of a large drum with a unit that took the boiled off oxygen to the patient in a regulated matter. There was the large floor drum and a small portable unit. As I teenager I would fill up the portable unit on a regular basis. It was simple, just connect it to the nozzle, check to make sure it was tight and open the values until the light went from yellow to green, then close the values and disconnect it. It seems that if it was used in medical technology 40 years ago it could be adapted to aerospace technology today.
BTW such systems are still available today in a much streamlined form.
http://www.advantagemedicalsystems.com/medical-equipment-oxygen.htm
Seems to me if it works in the home handled by your average senior you could make a system that trained astronauts could use safely IF there was a demand for it.
Two differences jump out at me. Zero G and you are transferring LOX not it’s boil off gas. Space doesn’t need to be harder if we understand the differences, but we must understand the differences.
Ken,
it was LOX that was transferred between the big drum tank and the small portable one, not boil off. It only took a few minutes. And at the time the large drum tank would be refilled in a service truck that came every few days. They would just wheel it out to the truck and fill it from the large LOX tank it had. These days that step has been replaced with a unit that produces the LOX from the atmosphere and stores it in the tank, but you still need to fill up the small portable ones.
Also the transferred is controlled by pressure, so zero gravity would not be an issue. In fact it would just be eliminating another variable, the position of the tank relative to a gravity field.
No, the reason no one has done cryogenic fuel depots or demonstrated the technology is simple, lack of demand. When the demand is there it will be done. That is how markets work,
And again the ISS is a good example. When it made sense for it to have its own propulsion system for adjusting it orbit it made sense for the Russians to design a refueling capability for it, one which has been working without issues for over a decade. Again, technology advances by market pull and need, not by pushing it. All a NASA demonstration of a fuel depot will do is send the message its complex, expensive and difficult to do, just as NASA mismanaged demonstration programs have done for SSTO and RLVs. (NSP, X-33, X-34…)
“Also the transferred is controlled by pressure, so zero gravity would not be an issue. In fact it would just be eliminating another variable, the position of the tank relative to a gravity field.”
To get pressure you need gas or mechanical piston- a full sealed syringe works in microgravity. But practice of insuring no air bubbles in syringe
would not work in microgravity. Air is not more buoyant than water in microgravity.
So air bubbles in water would be vaguely like air bubbles in honey {though one can use surface tension property of water}.
So a space which collapses [a bladder or piston] works in microgravity and pressurizing a liquid with gas doesn’t. Nor can you force gas out of container with pressure [though one could change the phase gas into liquid with pressure [or cooler temperature]].
Reply to gbaikie, October 22, 2013 at 1:35 pm
2. But accumulate cash may mean mostly pay for interest on capital
cost
The capital cost is around $200m. You can get that kind of money for around 10% but let’s say 15% which would be $30m annual. Bigelow’s plan is to charge $26m for a two month stay which almost covers that cost even if demand is only one person for 1/6th of a year. Full occupancy would be $26m x 36 or almost a billion dollars ($936m – $30m.) Any more than one and you have positive cash flow with a considerable potential range for huge profits. When word gets out, dozens of companies will be orbiting habitats even if they have no mars plans.
3. I think Ion engine would work better in Cislunar space
It is Cislunar space; specifically running fuel from the ship to the depot.
4. This is private operation, right?
Yes, meaning they would buy from anyone if the price is reasonable and this would tend to promote greater traffic.
5. We don’t care about the Moon?
If you have fuel capacity to go to mars, then you have fuel capacity for the moon.
6. then some depot at lunar orbit…
I just picked one scenario. I said we should compare the numbers to others.
7a. Paraphrase: Whose show is this?
Whomever has the brains to risk the first $200m.
7b. Why don’t start by placing in EML1?
The whole point of this exercise is to encourage lots of companies to be fuel providers and provide a leasing opportunity so it starts as a profitable venture. LEO is relatively stable and easier to get to. If not in LEO you’d lower your leasing market by raising costs. You’d reduce the number of companies competing to supply fuel.
The Langrange points have pluses and minuses. You can’t just exclude the minuses. EML 1, 2 & 3 are not entirely stable. EML 4 & 5 being stable probably have lots of debris floating around. The main advantage of a Lagrange point is fuel savings highway but only if that’s done right as well.