Speculation thread: intermediate-lift Raptor-derived RLV

[GWH]

Dragon doesn't have nearly enough dV to be an MAV, though.

Not at all what I was suggesting, although some derivative with a substantial trunk mounted propulsion COULD, such as one might want for a lunar lander/ascent vehicle, which itself is a tall order. 

Using the MITS as a SSTO booster and dragon as a payload would be the idea: 
One Dragon as crewed Earth launch docks in LEO to MITS based transit habitat, then acts as Mars descent vehicle.  One Dragon acting as a payload on a MITS as the MAV's crew capsule, dock in orbit to MITS based transit habitat, then used to land crew on Earth.   Add a tanker in Martian orbit for the dV.
A lot less cost effective in the long run than a true MITS based crew vehicle, but I think that would be an effective trade off when considering the MITS architecture to fast-track crew missions to Mars pre-ITS.

MITS in my opinion would be best as a cargo vehicle, at least at first, so it can be fast-tracked easier than a fully integrated crewed spacecraft like the ITS.

[sevenperforce]

Dragon doesn't have nearly enough dV to be an MAV, though.

Not at all what I was suggesting, although some derivative with a substantial trunk mounted propulsion COULD, such as one might want for a lunar lander/ascent vehicle, which itself is a tall order. 

Using the MITS as a SSTO booster and dragon as a payload would be the idea: 
One Dragon as crewed Earth launch docks in LEO to MITS based transit habitat, then acts as Mars descent vehicle.  One Dragon acting as a payload on a MITS as the MAV's crew capsule, dock in orbit to MITS based transit habitat, then used to land crew on Earth.   Add a tanker in Martian orbit for the dV.
A lot less cost effective in the long run than a true MITS based crew vehicle, but I think that would be an effective trade off when considering the MITS architecture to fast-track crew missions to Mars pre-ITS.

MITS in my opinion would be best as a cargo vehicle, at least at first, so it can be fast-tracked easier than a fully integrated crewed spacecraft like the ITS.

I think a methalox F9/FH upper stage is reasonably likely, but I think if they DO make one, it's likely that they would go for full reuse from the very beginning. If they are going for full reuse, I see them doing a fixed payload bay rather than fairings; if you're bringing it all back, why not do it at once? And so the rest of the design kind of emerges from that.

Making it man-rated would be tough, I admit.

[guckyfan]

A fixed payload bay instead of a fairing would be nice. But would a methane upper stage that is designed to be interchangeably used with the Merlin upper stage have enough payload capacity to GTO? The full weight of that payload bay would come out of the GTO capacity. That's a big loss, assuming no refuelling for GTO flights.

Edit: If that were their plan then why would they develop fairing reuse now, just for the interim?

[sevenperforce]

A fixed payload bay instead of a fairing would be nice. But would a methane upper stage that is designed to be interchangeably used with the Merlin upper stage have enough payload capacity to GTO? The full weight of that payload bay would come out of the GTO capacity. That's a big loss, assuming no refuelling for GTO flights.

Edit: If that were their plan then why would they develop fairing reuse now, just for the interim?

They still plan to fly Falcon 9 and Falcon Heavy with the kerolox upper stage for quite some time, so fairing recovery can still save them money now.

In any case, there's not a significant payload hit for a fixed fairing. With recovery, it can take up to 5 tonnes of payload to GTO if it is launched on Falcon 9 with ASDS recovery and 13.1 tonnes to GTO if it is launched on Falcon Heavy with all three cores recovered. That's factoring the fixed fairing/payload bay into the stage dry mass.

[Norm38]

This rendering is from the Purdue University study (http://forum.nasaspaceflight.com/index.php?topic=42790.0), which they call ITS-A.  It's based on the full size ITS, but includes cargo bay and would be optimized for LEO operation. It's basically Space Shuttle 2.0. A fully reusable TSTO.  Payload may be FH class, not sure.  The Purdue students designed it specifically to assemble a Mars Cycler, but it could also launch satellites and assemble/service space hotels, commercial labs, fuel depot, etc.

Now it's not subscale, it is full scale.  But what this does is give the 1st stage booster a way to earn money.  It allows the second stage to make money by starting with smaller payloads and working its way up.
By that I mean that at first TPS and landing systems could be overdesigned.  Plenty of fuel margin allocated.  No solar arrays to start, or much smaller and simpler, disposable even.  They should have plenty of performance margin and still be able to launch everything in sight and expand the market.  Fuel is cheap, so if the system is fully reusable, why not go full scale?

And this then grows into the Mars rated ITS.  Development craft can spend 6 months in LEO testing out life support and other systems.  It can extend and retract the solar arrays a hundred times to test that mechanism.  Whatever it needs to do.
NASA can use it for ISS (or whatever comes after ISS).  Bigelow can use it.  With the Shuttle retired, we need a new space truck.

[sevenperforce]

This rendering is from the Purdue University study (http://forum.nasaspaceflight.com/index.php?topic=42790.0), which they call ITS-A.  It's based on the full size ITS, but includes cargo bay and would be optimized for LEO operation. It's basically Space Shuttle 2.0. A fully reusable TSTO.  Payload may be FH class, not sure.  The Purdue students designed it specifically to assemble a Mars Cycler, but it could also launch satellites and assemble/service space hotels, commercial labs, fuel depot, etc.

Now it's not subscale, it is full scale.  But what this does is give the 1st stage booster a way to earn money.  It allows the second stage to make money by starting with smaller payloads and working its way up.
By that I mean that at first TPS and landing systems could be overdesigned.  Plenty of fuel margin allocated.  No solar arrays to start, or much smaller and simpler, disposable even.  They should have plenty of performance margin and still be able to launch everything in sight and expand the market.  Fuel is cheap, so if the system is fully reusable, why not go full scale?

And this then grows into the Mars rated ITS.  Development craft can spend 6 months in LEO testing out life support and other systems.  It can extend and retract the solar arrays a hundred times to test that mechanism.  Whatever it needs to do.
NASA can use it for ISS (or whatever comes after ISS).  Bigelow can use it.  With the Shuttle retired, we need a new space truck.

Landing leg placement is all wrong, but otherwise, beautiful!

[Lars-J]

Yes, this kind of ITS-cargo vehicle is assumed by most (myself included) to be an obvious development that would earn the bills between Mars launch windows.

[spacenut]

Could a mini-ITS and an intermediate Raptor booster do Mars using fuel depots, SEP tugs, and maybe a reusable lander (mini-ITS) stationed only at Mars to take SEP cargo to the surface, refuel, and bring more down to the surface?

From earth launch cargo on a mini-its, offload to SEP tugs, and return to earth for more cargo. 

A refueled mini-ITS could take passengers direct to shorten the trip.  Say 20-50 passengers instead of the 100. 

The Martian mini-ITS can also bring up argon derived from the Mars atmosphere for a SEP tug to return to earth for more cargo. 

SEP tugs could be refueled with Falcon Heavies from earth for return trip to Mars.

[Robotbeat]

Auxiliary methane thrusters will be needed for the booster anyway. Might as well use them on a scaled BFS.

[M.E.T.]

This rendering is from the Purdue University study (http://forum.nasaspaceflight.com/index.php?topic=42790.0), which they call ITS-A.  It's based on the full size ITS, but includes cargo bay and would be optimized for LEO operation. It's basically Space Shuttle 2.0. A fully reusable TSTO.  Payload may be FH class, not sure.  The Purdue students designed it specifically to assemble a Mars Cycler, but it could also launch satellites and assemble/service space hotels, commercial labs, fuel depot, etc.

Now it's not subscale, it is full scale.  But what this does is give the 1st stage booster a way to earn money.  It allows the second stage to make money by starting with smaller payloads and working its way up.
By that I mean that at first TPS and landing systems could be overdesigned.  Plenty of fuel margin allocated.  No solar arrays to start, or much smaller and simpler, disposable even.  They should have plenty of performance margin and still be able to launch everything in sight and expand the market.  Fuel is cheap, so if the system is fully reusable, why not go full scale?

And this then grows into the Mars rated ITS.  Development craft can spend 6 months in LEO testing out life support and other systems.  It can extend and retract the solar arrays a hundred times to test that mechanism.  Whatever it needs to do.
NASA can use it for ISS (or whatever comes after ISS).  Bigelow can use it.  With the Shuttle retired, we need a new space truck.

This makes so much sense that it seems almost inevitable, if the ITS is to go ahead. In fact, the general cargo ITS seems like it should be the very first version of the ITS variants designed, before the crew spaceship and tanker versions are built.

Such a cargo vessel would immediately render Falcon Heavy obsolete, and since it is fully reusable, might even make F9 obsolete, other than perhaps for minimal payloads that allow F9 RTLS. And even then, I'm not sure which would be cheaper, given that full reusability of F9 still seems unlikely, unlike the ITS cargo.

In any case, this would give ITS an immediate income stream, and allow the booster and upper stage to fly dozens of times a year before any manned flight needs to be risked. The massive financial benefits from such a reusable bulk cargo transporter would then go a long way in funding the development of the crew and tanker ITS variants.

It seems the logical progression to follow. And would provide the smoothest transition from the current Falcon based business model to a new ITS based architecture.

[rsdavis9]

Such a cargo vessel would immediately render Falcon Heavy obsolete, and since it is fully reusable, might even make F9 obsolete, other than perhaps for minimal payloads that allow F9 RTLS. And even then, I'm not sure which would be cheaper, given that full reusability of F9 still seems unlikely, unlike the ITS cargo.

and why is a mini version better than just the full sized ITS with a cargo version?

[M.E.T.]

Such a cargo vessel would immediately render Falcon Heavy obsolete, and since it is fully reusable, might even make F9 obsolete, other than perhaps for minimal payloads that allow F9 RTLS. And even then, I'm not sure which would be cheaper, given that full reusability of F9 still seems unlikely, unlike the ITS cargo.

and why is a mini version better than just the full sized ITS with a cargo version?

Sorry if I misinterpreted something, but my reading of the rendering from the Purdue study above is that it IS a full sized ITS cargo version, not a mini version. It is the full size one that I am saying is the logical next step, not a mini sized version at all.

[rsdavis9]

Such a cargo vessel would immediately render Falcon Heavy obsolete, and since it is fully reusable, might even make F9 obsolete, other than perhaps for minimal payloads that allow F9 RTLS. And even then, I'm not sure which would be cheaper, given that full reusability of F9 still seems unlikely, unlike the ITS cargo.

and why is a mini version better than just the full sized ITS with a cargo version?

Sorry if I misinterpreted something, but my reading of the rendering from the Purdue study above is that it IS a full sized ITS cargo version, not a mini version. It is the full size one that I am saying is the logical next step, not a mini sized version at all.

It might be me who has misinterpreted something. I guess I am questioning what the reasons are that ITS is not the right vehicle for earth based payload launches. Why do we need a completely different vehicle to do cargo to near earth orbit?

[M.E.T.]

Such a cargo vessel would immediately render Falcon Heavy obsolete, and since it is fully reusable, might even make F9 obsolete, other than perhaps for minimal payloads that allow F9 RTLS. And even then, I'm not sure which would be cheaper, given that full reusability of F9 still seems unlikely, unlike the ITS cargo.

and why is a mini version better than just the full sized ITS with a cargo version?

Sorry if I misinterpreted something, but my reading of the rendering from the Purdue study above is that it IS a full sized ITS cargo version, not a mini version. It is the full size one that I am saying is the logical next step, not a mini sized version at all.

It might be me who has misinterpreted something. I guess I am questioning what the reasons are that ITS is not the right vehicle for earth based payload launches. Why do we need a completely different vehicle to do cargo to near earth orbit?

I can think of two reasons off hand. Make that three.

1. ITS has a lot of internal space dedicated to crew accommodation, which cannot be used for bulk cargo purposes.

2. ITS does not have large enough cargo doors to deliver a payload that utilizes most of its internal space.

3. ITS has a lot of expensive hardware related to life support and other long range Mars colonization activities which make it less efficient as a pure cargo carrier.

Consider for example that if you could use the entire payload to LEO capability of the ITS for large bulk cargo, you could come close to lofting the entire 400 ton ISS to LEO in one launch.

EDIT

The cargo ITS could then be the "Dragon", while the eventual crew ITS could be the "Dragon 2, crew version" which is built upon the foundation of the cargo ship.

[spacenut]

I think the Mini-ITS would cost less overall to develop and can be developed more quickly.  Infrastructure for one.  A Mini-ITS can use existing pad 39A or B and would cost less to modify than a whole new launch pad.  Transportation from any factory along the waterways would be easier. 

I reading so much, I don't really know which ITS version is going to be developed.  The 12m version can take advantage of the existing river and intercoastal waterways, so factory doesn't have to be at or near the launch pad.  However, a new pad and facilities would have to be developed. 

Mini-ITS to me would be about 7-8m in diameter and be able to launch 75 tons to LEO fully reusable. 

[M.E.T.]

I think the Mini-ITS would cost less overall to develop and can be developed more quickly.  Infrastructure for one.  A Mini-ITS can use existing pad 39A or B and would cost less to modify than a whole new launch pad.  Transportation from any factory along the waterways would be easier. 

I reading so much, I don't really know which ITS version is going to be developed.  The 12m version can take advantage of the existing river and intercoastal waterways, so factory doesn't have to be at or near the launch pad.  However, a new pad and facilities would have to be developed. 

Mini-ITS to me would be about 7-8m in diameter and be able to launch 75 tons to LEO fully reusable.

But then you would still need to develop a separate full size cargo version, full size crew version and full size tanker version. Whereas if you went straight for a full size cargo version, it would likely be significantly less complex than the full size crew version, with less required functionality, no life support, far simpler internal design and far more cargo capability.

And it would then retire the mini version, making all of that interim development work a wasted exercise.

[rsdavis9]

I think the Mini-ITS would cost less overall to develop and can be developed more quickly.  Infrastructure for one.  A Mini-ITS can use existing pad 39A or B and would cost less to modify than a whole new launch pad.  Transportation from any factory along the waterways would be easier. 

I reading so much, I don't really know which ITS version is going to be developed.  The 12m version can take advantage of the existing river and intercoastal waterways, so factory doesn't have to be at or near the launch pad.  However, a new pad and facilities would have to be developed. 

Mini-ITS to me would be about 7-8m in diameter and be able to launch 75 tons to LEO fully reusable.

But then you would still need to develop a separate full size cargo version, full size crew version and full size tanker version. Whereas if you went straight for a full size cargo version, it would likely be significantly less complex than the full size crew version, with less required functionality, no life support, far simpler internal design and far more cargo capability.

And it would then retire the mini version, making all of that interim development work a wasted exercise.

Yes this was actually my point which I failed to articulate properly.
As far as I understand it the falcon is the biggest rocket(3.6m) that can get road transported. All bigger stages require barge/train. So what is the advantage of the mini?

[M.E.T.]

I think the Mini-ITS would cost less overall to develop and can be developed more quickly.  Infrastructure for one.  A Mini-ITS can use existing pad 39A or B and would cost less to modify than a whole new launch pad.  Transportation from any factory along the waterways would be easier. 

I reading so much, I don't really know which ITS version is going to be developed.  The 12m version can take advantage of the existing river and intercoastal waterways, so factory doesn't have to be at or near the launch pad.  However, a new pad and facilities would have to be developed. 

Mini-ITS to me would be about 7-8m in diameter and be able to launch 75 tons to LEO fully reusable.

But then you would still need to develop a separate full size cargo version, full size crew version and full size tanker version. Whereas if you went straight for a full size cargo version, it would likely be significantly less complex than the full size crew version, with less required functionality, no life support, far simpler internal design and far more cargo capability.

And it would then retire the mini version, making all of that interim development work a wasted exercise.

Yes this was actually my point which I failed to articulate properly.
As far as I understand it the falcon is the biggest rocket(3.6m) that can get road transported. All bigger stages require barge/train. So what is the advantage of the mini?

And furthermore, it seems the whole road transport limitation is something that will have to be overcome in the end if we are to go to heavy lift vehicles of the future. So just go and build the entire factory at Boca Chica, and end the transport problem for good.

[sevenperforce]

Could a mini-ITS and an intermediate Raptor booster do Mars using fuel depots, SEP tugs, and maybe a reusable lander (mini-ITS) stationed only at Mars to take SEP cargo to the surface, refuel, and bring more down to the surface?

From earth launch cargo on a mini-its, offload to SEP tugs, and return to earth for more cargo. 

A refueled mini-ITS could take passengers direct to shorten the trip.  Say 20-50 passengers instead of the 100. 

The Martian mini-ITS can also bring up argon derived from the Mars atmosphere for a SEP tug to return to earth for more cargo. 

SEP tugs could be refueled with Falcon Heavies from earth for return trip to Mars.

Yes, precisely. But it's even better than this; you don't need an intermediate raptor booster, since a mini-ITS could launch on Falcon 9 or Falcon Heavy just as easily. As long as you have orbital refueling, the mini-ITS alone (or combinations thereof) could do pretty much all the Mars missions you can think of. A couple of pages back I outlined a fully-reusable 2020 Mars Sample Return for the cost of just two reusable Falcon Heavy launches plus refueling runs. Getting crew to Mars requires a transhab, which is a little more challenging, but I think doable.

No SEP required.

Auxiliary methane thrusters will be needed for the booster anyway. Might as well use them on a scaled BFS.

Makes landing a lot easier, and allows you to avoid the lossy step of including a SL Raptor.

I think the Mini-ITS would cost less overall to develop and can be developed more quickly.  Infrastructure for one.  A Mini-ITS can use existing pad 39A or B and would cost less to modify than a whole new launch pad.  Transportation from any factory along the waterways would be easier. 

I reading so much, I don't really know which ITS version is going to be developed.  The 12m version can take advantage of the existing river and intercoastal waterways, so factory doesn't have to be at or near the launch pad.  However, a new pad and facilities would have to be developed. 

Mini-ITS to me would be about 7-8m in diameter and be able to launch 75 tons to LEO fully reusable.

But then you would still need to develop a separate full size cargo version, full size crew version and full size tanker version. Whereas if you went straight for a full size cargo version, it would likely be significantly less complex than the full size crew version, with less required functionality, no life support, far simpler internal design and far more cargo capability.

And it would then retire the mini version, making all of that interim development work a wasted exercise.

Yes this was actually my point which I failed to articulate properly.
As far as I understand it the falcon is the biggest rocket(3.6m) that can get road transported. All bigger stages require barge/train. So what is the advantage of the mini?

You can get up to around 4 meters of diameter onto the road; length is more an issue.

[OneSpeed]

You can get up to around 4 meters of diameter onto the road; length is more an issue.

Are you sure? The US highway standards are: Vertical clearance: Minimum vertical clearance under overhead structures (including over the paved shoulders) of 16 feet (4.9 m) in rural areas and 14 feet (4.3 m) in urban areas. The F9 appears to be over 5 metres already.