Low-cost Launch Vehicle Concept

[shynung]

I recently came across a PDF from 2005:

http://www.responsivespace.com/Papers/RS3/SESSION%20PAPERS/SESSION%206/6001-TURNER/6001C.pdf

It describes Aquarius, a low-cost, SSTO launch vehicle envisioned to carry only bulk items (fuel, water, food, duct tape, etc) to LEO, for transfer to a depot via orbital space tug. Interestingly, launch failures of up to 1/3 of total launches is considered acceptable, even after considering the costs of typical payloads.

I'd like to hear your opinions, considering your experience as KSP players, as to the viability of such spacecraft, and its possible uses.

P.S. Haven't made a vertical SSTO yet, so this might be a good practice.

[dharak1]

Looks real cool! The image with 3 made me think they would be smaller than the 43 meter long measurement given.

[MC.STEEL]

its an intersting concept but the 1/3 failure rate is realy bugging me.

[palioxis1248]

its an intersting concept but the 1/3 failure rate is realy bugging me.

Well, it's basically a modern-day ATV to orbit. Since it was supposed to be dirt-cheap, I'm guessing that if a launch failed you could just send up another one.

[jwenting]

Well, it's basically a modern-day ATV to orbit. Since it was supposed to be dirt-cheap, I'm guessing that if a launch failed you could just send up another one.

Tell that to the customer who spent 200 million and 10 years constructing the payload, or their insurance company who'll have to cover the 200 million but the 10 years is irretrievably lost.

[sgt_flyer]

1-ton payload to LEO would be really low for an ATV - current ATV's (progress, Dragon and ESA's ATV) use 8/13/20 tons to LEO launchers. So the main use would be only for light satellites - which are quite pricey if the failure rate is indeed 1/3 , there's not many insurances companies which would want to work with this kind of launcher (especially if they have to spend time/money to rebuild the satellites - the lost time for their engineers would not really be attractive, even with insurances )

[Ralathon]

Note that they build it for bulk goods. This wouldn't be used for small sats, it would be used for food and fuel to the ISS and other stations. Nobody cares if half a ton of sandwiches explodes.

[Albert VDS]

A Falcon 9 costs $4,109 per kg, it can put a much bigger payload into orbit and it has a higher success rate.

So the Aquarius is 4 times cheaper, but I rather spend 4 times more for reliability and payload space.

Note that they build it for bulk goods. This wouldn't be used for small sats, it would be used for food and fuel to the ISS and other stations. Nobody cares if half a ton of sandwiches explodes.

It's not unlikely, if you have a 1/3 failure rate, that you'll have 3 failures(or more in a row). Again, I rather bet on the F9.

Edited January 26, 2014 by Albert VDS

[TechnicalK3rbal]

-snip-

It's not unlikely, if you have a 1/3 failure rate, that you'll have 3 failures(or more in a row). Again, I rather bet on the F9.

At first I thought you meant quickload (F9),

then I realized it was falcon 9....

[Roastduck]

A Falcon 9 costs $4,109 per kg, it can put a much bigger payload into orbit and it has a higher success rate.

So the Aquarius is 4 times cheaper, but I rather spend 4 times more for reliability and payload space.

Not to mention that Progress/Dragon/whatever will send up at least 8 times as much cargo, so the Aquarius actually ends up costing twice as much to send up the same cargo.

[K^2]

Tell that to the customer who spent 200 million and 10 years constructing the payload, or their insurance company who'll have to cover the 200 million but the 10 years is irretrievably lost.

That's why the fact that proposed payload is bulk low cost consumables has been stressed several times.

[Albert VDS]

It shouldn't matter if it's low cost bulk consumables, nothing justifies such a horrible success rate.

Imagine you drive to supermarket to get groceries and you have your car explode 1/3 of the time(and you are the only one who stays intact).

I doubt it would take long before you had enough of exploding cars and bought one which has less chance of blowing up.

Or package would you pick a package service if it would state: "We can guarantee that your package has a 2/3 chance of being delivered! and 1/3 of blowing up..."

Edited January 26, 2014 by Albert VDS

[maccollo]

Nowhere does it it say the expected failure rate would be 1/3. It says that the cost is so low it would be competitive even if the failure rate was that high.

And it's just intended to launch consumables anyways, so the cost of the potential loss of the payload in the event of a failed launch is irrelevant. The cost of the launch vehicle is all that matters.

The thing that bothers me is the flexibility of this thing. The dry mass to payload fraction is 10:1, which determine how much further it can go by lowering the payload mass.

So less than 10% of the final mass is payload. The space shuttle had a payload fraction of 25% of the final dry mass. The dry mass of the orbiter was a little less than 70 tons, maximum payload capacity to LEO was 24 tons. In order to get into a polar orbit it had to lower the mass of the payload to 12 tons, which is a 50% loss in payload mass, and 15% loss in the maximum mass it could deliver. So with a payload to total mass fraction of less than 10% I don't think this thing can get into a polar orbit at all.

[Kryten]

The thing that bothers me is the flexibility of this thing. The dry mass to payload fraction is 10:1, which determine how much further it can go by lowering the payload mass.

So less than 10% of the final mass is payload. The space shuttle had a payload fraction of 25% of the final dry mass. The dry mass of the orbiter was a little less than 70 tons, maximum payload capacity to LEO was 24 tons. In order to get into a polar orbit it had to lower the mass of the payload to 12 tons, which is a 50% loss in payload mass, and 15% loss in the maximum mass it could deliver. So with a payload to total mass fraction of less than 10% I don't think this thing can get into a polar orbit at all.

Why would you need to put bulk consumables in polar orbit?

[maccollo]

Well, in short you wouldn't. I just used that as an example to show how it would be severely limited in it's flexibility, and as the inclination of the orbit increases from the equatorial plane the potential payload would drop much faster than other rockets, like the falcon 9.

Now, I couldn't find anything about how far this thing can take that one ton they specified.

If it's to the space station, then this thing can take consumables to the space station and no further. But if it can take that to an equatorial orbit they it will have quite a severe reduction in payload capacity to a 50 degree inclination, which is what the the inclination of the space station.

A reduction in payload capacity means the price per kg goes up.

So I guess what I'm trying to say is.... If you want to launch something to whatever orbit it can deliver 1 ton to, then it will be cheap, but any orbit that requires just slightly more delta V will result in a rapid increase in price per kg.

Edited January 26, 2014 by maccollo

[Ralathon]

It shouldn't matter if it's low cost bulk consumables, nothing justifies such a horrible success rate.

Imagine you drive to supermarket to get groceries and you have your car explode 1/3 of the time(and you are the only one who stays intact).

I doubt it would take long before you had enough of exploding cars and bought one which has less chance of blowing up.

Or package would you pick a package service if it would state: "We can guarantee that your package has a 2/3 chance of being delivered! and 1/3 of blowing up..."

Look, to go with your supermarket analogy:

You can pick one, wreck a Lamborghini for a near guaranteed success on getting groceries or wreck a cheap van with a 1/3th chance that your groceries don't make it and you have to redo the drive.

You're going to lose the rocket either way, and that's the main factor driving cost. If the rocket is cheap and the payload is something essential but cheap nobody is going to care about success rates.

[K^2]

It shouldn't matter if it's low cost bulk consumables, nothing justifies such a horrible success rate.

Imagine you drive to supermarket to get groceries and you have your car explode 1/3 of the time(and you are the only one who stays intact).

I doubt it would take long before you had enough of exploding cars and bought one which has less chance of blowing up.

Now imagine that you had to buy a new car every time you got groceries, and somebody offered you a car at 1/4 of the price which has 1 in 3 odds of blowing up. Because that's more like what's going on here, and that's, actually, a great deal.

[rpayne88]

So it can only deliver one ton to orbit and may fail up to 1/3 of the time. The only advantage it would have going for it is that it is an SSTO. But, why make an SSTO with no recovery system and reenter it in such a way that it breaks up?

[Nibb31]

It doesn't go to the ISS. It goes to a parking orbit where a tug meets with it and brings the payload to the ISS.

I understand it would be cheap, but what I don't get is the payload. It's only 1 ton. Even at a very low price, delivering consumables ton by ton doesn't make much sense. Any sort of fuel depot would need dozens of launches to refill between two missions, so to deliver 20 tons of propellant your rocket would have to be 20 times cheaper than a Proton or an Ariane V. It will also take ages (and a lot of delta-v) for the tug to do all the hauling and rendez-vous stuff for those 20 supply runs.

It's likely that the tug would have to spend more than 1 ton of propellant just to go and bring the payload to the ISS or fuel depot.

Also, a toroidal tank around the engine seems like a strange place to put it and also like a hard place to rendez-vous with, potentially dirty with burn residue and ablated debris from the nozzle. Not the most appropriate place to put a docking ring or a fuel transfer valve.

Edited January 26, 2014 by Nibb31

[crazyewok]

Nobody cares if half a ton of sandwiches explodes.

I dunno if I was on the ISS and say my dinner explode I would ne abit sad.

[Nibb31]

So it can only deliver one ton to orbit and may fail up to 1/3 of the time. The only advantage it would have going for it is that it is an SSTO. But, why make an SSTO with no recovery system and reenter it in such a way that it breaks up?

Because 1 stage is supposed to be cheaper than 2 stages... I'm not sure that it applies universally, but that's their reasoning.

An SSTO doesn't have to be reusable. A reusable doesn't have to be SSTO.

[K^2]

Any sort of fuel depot would need dozens of launches to refill between two missions, so to deliver 20 tons of propellant your rocket would have to be 20 times cheaper than a Proton or an Ariane V. It will also take ages (and a lot of delta-v) for the tug to do all the hauling and rendez-vous stuff for those 20 supply runs.

Which it is, seeing how cost per ton of cargo is much lower. I mean, at the end of the day, that's what you care about. How much it cost you to deliver X amount of cargo.

It's likely that the tug would have to spend more than 1 ton of propellant just to go and bring the payload to the ISS or fuel depot.

Why don't you do the math on this before making claims like that?

[Nuke]

this makes me wonder why we cant just do the same thing but make it more reliable. if you can get the reliability up to 90% then you would have something. if you mass produce these things, you can always fix problems as they present themselves. figure out whats going wrong 1/3 of the time and fix it. you still have an assembly line turning these things out like crazy, so its still cheap.

Edited January 26, 2014 by Nuke

[Nibb31]

Why don't you do the math on this before making claims like that?

Well, math is hard, and I suck at it, which is why I used the word "likely". I'm sure much smarter people will be able to figure it out.

The study in the OP doesn't go into much detail about the tug, and I don't thing there are any off-the-shelf upperstages that could serve as a comparison. The Soyuz/Progress SM carries ~2 tons of propellant and only has 390 m/s of delta. It's not a good comparison, because this tug would be much smaller and lighter, but it would also have to be able to do at least twice the orbital changes that are necessary for Soyuz/Progress mission. A closer idea would probably be the Cygnus service module, but I couldn't find the size of its propellant tanks or its dV.

To calculate the required dV, we would need to know what they would typically use as a parking orbit, which we don't, but I suspect that it would have to be at a safe distance from the ISS, especially if the rocket has a 30% chance of failure

Yeah, maybe I was overestimating with 1 ton of tug propellant for each supply run, but the tug still needs to be refueled, and that will take a significant chunk of the total payload capacity.

My point was that the study concentrates on the rocket but ignores the operational cost of the tug, the cost of the incessant manoeuvers and operations that need to be tracked on the ground, the additional ISS docking requirements and the disruption to ISS operations.

[sgt_flyer]

Edit : heh : beat to the spot by nibb31 about the indirect costs

Even if we can make it more reliable, before being able to build it they will have to create absolutely huge factories to sustain the production rates which would be needed to make it useful. (1 engine per 1 ton of payload - spacex want to build 40 engines a month).

Then, if those rockets are used only for bulk goods, at 1 ton each it would create way too much docking events for reliable use (as the main targets would likely be manned space stations)

if the goods need to go to iss (for example) each spacecraft docking to iss require lengthy verification procedures, to check if the spacecraft has no problems before the astronauts open the hatches.

So maybe it would be low cost to build - but i don't think it takes into account indirect costs it would generate (tracking / manoeuvering each payload once in orbit, 'lost' astronauts time for each docking, etc.

Personally, i don't think the low payload capacity is suited for ferrying bulk goods to space.

Now, if they can make the rocket reliable, it would be an excellent launcher for small satellites.

Edited January 27, 2014 by sgt_flyer