New Glenn Evolution Speculation and Discussion

[Eric Hedman]

New Glenn hasn't flown yet, but like other rockets it will have the potential to evolve.  It may get a reusable second stage.  It may get a tanker version for refueling.  It may be fly a crewed capsule.  The engines could be upgraded.  This thread is to discuss what is likely to happen, when and why.

[Darkseraph]

Payload could potentially increase if the engines are gradually up-rated and sub-chilled propellants are used.

[Eric Hedman]

Payload could potentially increase if the engines are gradually up-rated and sub-chilled propellants are used.

How much could payload to LEO be increased by doing both?

[GWH]

Could also get a 3rd stage.
I'd be really excited to see it evolve to Block 1 SLS capacity to TLI.

[TrevorMonty]

Could also get a 3rd stage.
I'd be really excited to see it evolve to Block 1 SLS capacity to TLI.

As RLV not likely but as ELV maybe especially with addition of few SRBs. Better option is do distributed launch, one launch for Orion and another for EDS (Be7 powered).

[Robotbeat]

Could also get a 3rd stage.
I'd be really excited to see it evolve to Block 1 SLS capacity to TLI.

As RLV not likely but as ELV maybe especially with addition of few SRBs. Better option is do distributed launch, one launch for Orion and another for EDS (Be7 powered).

Not too different from the Ares I and Ares V setup. Or Gemini/Agena. It's funny to me that people forget so quickly that we've actually done this before...

[Eric Hedman]

I see a couple of possibilities for a reusable second stage.  Start with a payload bay doors on the nose so no need to dispose of fairings (some loss of payload capacity I know).  Then you have the choice of propulsive vertical landing or adding wings and gliding home.  Both would require adding some form of a heat shield.  Does anyone know of any other practical way without losing too much payload capacity of returning an upper stage from orbital speeds?

[Steve G]

Blue Origin has made it clear they don't intend to make the second stage reusable, and they went from a three stage version and in Jan 2019 dropped it. But, they have invested hugely into ground infrastructure, factories, etc, so they are in it for the long haul, and would expect some form of evolution. If Starship/Super Heavy is successful, they may have no choice but to compete. But that's still a big if.

I would suspect a third stage would be based on the BE-7 using the Blue Moon propulsion system and not the BE-3U as originally envisioned as it is already being developed.

A reusable second stage? Either a mini Starship or SpaceX's earlier designs for a Falcon 9 reusable design. Or, a great big biconic capsule carrying both humans and cargo. Just a wild guess, guys.

They are so secretive we can only guess, but a lot has to do with demand for lunar flights, and that's all politically-dependant.

[GWH]

Could also get a 3rd stage.
I'd be really excited to see it evolve to Block 1 SLS capacity to TLI.

As RLV not likely but as ELV maybe especially with addition of few SRBs. Better option is do distributed launch, one launch for Orion and another for EDS (Be7 powered).

Not too different from the Ares I and Ares V setup. Or Gemini/Agena. It's funny to me that people forget so quickly that we've actually done this before...

Yeah that's true that even with a 3rd stage New Glenn probably still can't match SLS B1 to TLI. It would be enough for Blue Moon and larger integrated payloads however.


Its too bad that distributed launch with only the existing 2nd stage as a departure stage and no refueling isn't a good for for New Glenn as designed.
Distributed launch with refueling would be enough to send Orion (or a similarly sized payload) through to TLI. Distributed launch using just residual propellants in dedicated departure stage (of New Glenn's 2nd stage) to LEO isn't enough though. Even assuming a full 45 tonnes of propellant to LEO for the departure stage it can't quite manage the 3.15km/s to TLI... assuming 0.9 propellant mas fraction of that 2nd stage.

New Glenn's S2 is just too big and stages too low to open up the more exciting distributed launch architectures - based on my crappy spreadsheet estimates that could be way off base.


That's why I think a good path forward is to get a reasonable sized 3rd stage going to open up options first - but don't stop there.  Make that 3rd stage refuelable (basically ACES) and then work on uprating the booster, stretching the 2nd stage, probably propellant densification, and achieving 2nd stage reuse so that a fully reusable architecture is achieved.

Basically copy SpaceX's path go going fast and expendable (upper stages) at first, then make a series of iterative improvements to increase reuse. A true in-space reusable 3rd stage is key there. One COULD try to achieve 2nd stage reuse for missions out to cislunar space, but one will always be fighting with that high dry mass (made worse through recovery hardware) and having to refuel more than necessary - which isn't great on a low cadence booster that has to land on a ship. A lot can be done in a single flight by utilizing a mass optimized reusable 3rd stage and only refueling that.

[TrevorMonty]

They may use NGIS TE as 3rd stage. Why reenvent wheel when one of their team mates can supply it. That frees up Blue's resources for developing other technology on their road map.

[Lars-J]

Blue Origin has made it clear they don't intend to make the second stage reusable, and they went from a three stage version and in Jan 2019 dropped it. But, they have invested hugely into ground infrastructure, factories, etc, so they are in it for the long haul, and would expect some form of evolution. If Starship/Super Heavy is successful, they may have no choice but to compete. But that's still a big if.

I think you are interpreting absence of evidence as evidence of absence. They have made no such thing clear. We only see what they let us see.

[GWH]

They may use NGIS TE as 3rd stage. Why reenvent wheel when one of their team mates can supply it. That frees up Blue's resources for developing other technology on their road map.

Trying to scale it from the renders and new info with the common bulkhead I get a total propellant mass of 18 tonnes for the transfer stage based off a 4.46 meter diameter. and 7.6 meter tank length.
They'd want to stretch the thing out to almost double that length to make for a real useful 3rd stage/tug, which pretty well occupies the entirety of New Glenn's payload fairing.
Good for distributed launch but rules out integrated launch options without an extended fairing.

[Welsh Dragon]

Blue Origin has made it clear they don't intend to make the second stage reusable, and they went from a three stage version and in Jan 2019 dropped it. But, they have invested hugely into ground infrastructure, factories, etc, so they are in it for the long haul, and would expect some form of evolution. If Starship/Super Heavy is successful, they may have no choice but to compete. But that's still a big if.

I think you are interpreting absence of evidence as evidence of absence. They have made no such thing clear. We only see what they let us see.

Have there been any developments from their VP saying it wasn't even on their roadmap last year? That seemed pretty clear to me...

[Eric Hedman]

Have there been any developments from their VP saying it wasn't even on their roadmap last year? That seemed pretty clear to me...

If no S2 reuse is in the cards for now, then the focus for improvements will be the usual suspects: lighter more robust structures, lower cost (especially to manufacture S2), improved engines, fuel densification,a possible third stage, and in space refueling.  That's still plenty of options to tackle in the next five or six years.

Also if S2 reuse is off the table for now due to technical difficulty, I would suspect any significant work on New Armstrong is off the table for now.  I can't imagine them designing New Armstrong without S2 reuse.  They need to get this rocket flying reliably and affordably.  Anything else other than Blue Moon is a distraction.  In the long haul Jeff Bezos is going to want a positive cashflow so he can do a lot more with the money he is investing.

[Comga]

New Glenn hasn't flown yet, but like other rockets it will have the potential to evolve.  It may get a reusable second stage.  It may get a tanker version for refueling.  It may be fly a crewed capsule.  The engines could be upgraded.  This thread is to discuss what is likely to happen, when and why.

What’s the point of this thread?
Look at the data point we have, the SpaceX Falcon 9
Who among us foresaw legs, grid fins, entry burns, cold gas thrusters on the first stage AND fairing halves, the parafoils, the octograbber, even the octoweb?  Even Musk had little idea how each of the problems would be solved, and he’s proud of that.
My guess is that there will be substantial changes necessary for success at the baseline capability. Once they make those changes and achieve that goal, flying mass to orbit and recovering the first stage, then we might see what opportunities exist and how BO might persue them.

[Eric Hedman]

What’s the point of this thread?

Speculation on what Blue might do.  Half the threads on this site are speculation on what might be done by the companies being followed.

[Robotbeat]

Blue Origin has made it clear they don't intend to make the second stage reusable, and they went from a three stage version and in Jan 2019 dropped it. But, they have invested hugely into ground infrastructure, factories, etc, so they are in it for the long haul, and would expect some form of evolution. If Starship/Super Heavy is successful, they may have no choice but to compete. But that's still a big if.

I think you are interpreting absence of evidence as evidence of absence. They have made no such thing clear. We only see what they let us see.

Have there been any developments from their VP saying it wasn't even on their roadmap last year? That seemed pretty clear to me...

Yes, we know for a fact that Blue Origin has considered reuse of the 2nd stage in the past and is firmly committed to full reuse in the long term.

That it's not in the immediate roadmap most certainly does NOT mean they don't intend to ever make the 2nd stage reusable. In fact, given the wording in that tweet (speaking of the technical difficulty), it seems clear to me they're
considering the possibility.

They've never launched anything to orbit. New Glenn is a massive challenge even expendably, and just getting first stage booster reuse to work will be a challenge for them and probably won't occur immediately. But they've repeatedly mentioned the possibility of 2nd stage reuse for New Glenn, so it is absolutely appropriate to discuss it here.

[GreenShrike]

New Glenn's S2 is just too big and stages too low to open up the more exciting distributed launch architectures - based on my crappy spreadsheet estimates that could be way off base.

That's why I think a good path forward is to get a reasonable sized 3rd stage going to open up options first - but don't stop there.  Make that 3rd stage refuelable (basically ACES) and then work on uprating the booster, stretching the 2nd stage, probably propellant densification, and achieving 2nd stage reuse so that a fully reusable architecture is achieved.

So, what you're saying is that Blue's first design for New Glenn, with the BE-4U methalox second stage and optional small BE-3U hydrolox third stage -- was more optimal? And that the current design is more of a kludge just to get New Glenn flying soonest? ;-)


I wonder if once the time pressure is off, they'll move back to the original architecture. I would imagine that a second stage that's a small copy of the booster with a single vac-optimized booster engine (e.g. Falcon 9) would be cheaper than a twin-engined hydrolox stage with dissimilar tankage to the booster and, absent full reuse, the reusable cost of the rocket will be governed by the cost of the expended equipment. In that case, a cheaper New Glenn second stage would improve their value versus the Falcon family, with their smaller Falcon upper stage expending less hardware than New Glenn's relatively larger second stage.


A fully reusable New Glenn would, of course, easily beat Falcon on pricing, but does Blue see the experience gained in the development a fully reusable NG as necessary (or at least valuable) in informing the design of New Armstrong? Or might they look at Starship and think they'll need NA soonest to compete?

Their "gradatim ferociter" thing makes guessing what Blue will do hard. When BE-4 ran into problems, they apparently just shrugged, changed the NG design to not require BE-4's follow-on, the BE-4U, and carried on carrying on. But does that mean they're willing to accept good enough? If so, Blue may steal a page from SpaceX and, once the current, only partially reusable New Glenn is finished development, focus on just flying New Glenn while directing all their development efforts on a fully reusable New Armstrong.

In that case, there will never be any evolution of New Glenn.

[envy887]

New Glenn's S2 is just too big and stages too low to open up the more exciting distributed launch architectures - based on my crappy spreadsheet estimates that could be way off base.

That's why I think a good path forward is to get a reasonable sized 3rd stage going to open up options first - but don't stop there.  Make that 3rd stage refuelable (basically ACES) and then work on uprating the booster, stretching the 2nd stage, probably propellant densification, and achieving 2nd stage reuse so that a fully reusable architecture is achieved.

So, what you're saying is that Blue's first design for New Glenn, with the BE-4U methalox second stage and optional small BE-3U hydrolox third stage -- was more optimal? And that the current design is more of a kludge just to get New Glenn flying soonest? ;-)


I wonder if once the time pressure is off, they'll move back to the original architecture. I would imagine that a second stage that's a small copy of the booster with a single vac-optimized booster engine (e.g. Falcon 9) would be cheaper than a twin-engined hydrolox stage with dissimilar tankage to the booster and, absent full reuse, the reusable cost of the rocket will be governed by the cost of the expended equipment. In that case, a cheaper New Glenn second stage would improve their value versus the Falcon family, with their smaller Falcon upper stage expending less hardware than New Glenn's relatively larger second stage.


A fully reusable New Glenn would, of course, easily beat Falcon on pricing, but does Blue see the experience gained in the development a fully reusable NG as necessary (or at least valuable) in informing the design of New Armstrong? Or might they look at Starship and think they'll need NA soonest to compete?

Their "gradatim ferociter" thing makes guessing what Blue will do hard. When BE-4 ran into problems, they apparently just shrugged, changed the NG design to not require BE-4's follow-on, the BE-4U, and carried on carrying on. But does that mean they're willing to accept good enough? If so, Blue may steal a page from SpaceX and, once the current, only partially reusable New Glenn is finished development, focus on just flying New Glenn while directing all their development efforts on a fully reusable New Armstrong.

In that case, there will never be any evolution of New Glenn.

The 3-stage version offers more performance per launch, but less performance per dollar. The 2 stage system with hydrolox upper is fine for distributed launch and refueling, if you can solve the LH2 storage hurdles.

While something like ACES or the Blue Moon DE as a reuseable-in-space tug or transfer vehicle is a good idea, it's not easy to reuse in LEO unless you go to the effort of aerobraking.

So if Blue goes to a 3 stage fully reusable system, I think it will be a methalox VTVL booster, a hydrolox VTVL upper stage (much like Starship), and a hydrolox transfer vehicle/lunar lander that stays above GTO.

[GWH]

The 3-stage version offers more performance per launch, but less performance per dollar. The 2 stage system with hydrolox upper is fine for distributed launch and refueling, if you can solve the LH2 storage hurdles.

While something like ACES or the Blue Moon DE as a reuseable-in-space tug or transfer vehicle is a good idea, it's not easy to reuse in LEO unless you go to the effort of aerobraking.

So if Blue goes to a 3 stage fully reusable system, I think it will be a methalox VTVL booster, a hydrolox VTVL upper stage (much like Starship), and a hydrolox transfer vehicle/lunar lander that stays above GTO.

Good points.

I ran through some fantasy rocket scenarios and changed my mind. If Blue Origin were to stick to payloads of existing sizes (such as the Blue Moon components) then a fully reusable system with a 3rd stage would be great.

If instead they decided to use in space refueling of their existing 2nd stage and try to maximize the payload to TLI or Gateway  they could really move some large masses. I am thinking of things like their wetlab space station like the one proposed in NASA's LEO commercialization studies.

One cargo launch of 33 tonnes to LEO with ~12 tonnes of residual propellants and refueled by a single tanker delivering 45 tonnes of propellant and they can put that cargo through to TLI.  Or 29 tonnes direct to Gateway using residual propellant from the cargo launch + 45 tonne top up.
Even better launch 45 tonnes to LEO then do 2 45 tonne tanker refuels and that mass can hauled to Gateway. 3 launches isn't bad.

If that's the case then New Glenn S2 functions as a minimum viable product to loft "traditional"payloads such as NSSL, GEO sats and NASA payloads to various destinations - then later in space refueling comes online and they look to establish propellant depots and space stations out at NHRO. Utilize New Glenn's performance to LEO and focus on dropping recurring production costs of expendable second stages.
There would be some significant work to be done to turn the second stage into a true refuelable space tug, but it would make for a good way to boot strap some infrastructure into deep space.

[yg1968]

On the issue of re-fueling, I wonder if it would be possible for New Glenn to use re-fueling of its second stage without the stage being re-usable?

[Solarsail]

Well, isn't that what ACES was trying to do with (similarly) hydrolox propellants?  They needed to use IVF to reduce the number of fluids to top up...  Do we know if the BE-3 family of engines are built for autogeneous pressurization?

[Darkseraph]

I have been thinking about the problem of second stage reuse and ways to achieve cost savings other than going down the current path that SpaceX is attempting with Starship. For smaller vehicles, landing the entire second stage could costly for payload capacity, takes a long time to develop and will make the entire stage a lot more complex.

Since engines tend to be the most costly part of any stage, what if you just recover them! Basically applying ULA's concept of SMART re-use, but for upper stage engine section. That uses a HIAD for entry and decent of just the engine section and a helicopter captures it. The fairings could also be captured in a manner similar to that being used on Falcon 9. Only the second stage propellant tanks are not recovered, which are a small fraction of the cost of the entire vehicle.

While it's not an immaculate solution and would not be as rapidly reusable as Starship promises to be, it could be a good enough interim solution. Returning the booster on a ship already limits how rapidly New Glenn can be reused and the demand for launches in the near term isn't high enough to require such a cadence.

[spacenut]

The second stage could have refueling capability and be used as a space tug. 

Or the engines returned and the tanks left for a fuel depot. 

[dante2308]

The second stage could have refueling capability and be used as a space tug. 

Or the engines returned and the tanks left for a fuel depot.

I'm sorry if this is a naïve question, but how could using second stages to refuel a second-stage tanker and result in a mass savings versus any space-optimized payload/propulsion pair? Wouldn't it be more efficient to launch an actual space tug and use/refuel that? My understanding was that New Glenn did not have a light second stage to begin with.

[spacenut]

The second stage itself would become the space tug.  The cargo for this tug would be say a Canada arm, and possibly a docking port.  Tanker second stages would refuel it.  Then a large payload could be attached, or several large payloads could be attached.  The fully fueled second stage tug would then transport 50-100 tons or more to say lunar orbit.  You don't waste the second stage, but refuel it.  Large single pieces of cargo launched from another New Glenn could then be taken to the moon orbit.  Individually New Glenn can only deliver what? 10-12 tons to the moon.  Refueling a second stage tug would allow much heavier payloads to be delivered to the Artemis orbit.  This idea has been floating around for 15 years or more using distributed launch and refueling to get larger payloads to cis-lunar space. 

Bezo's wants to industrialize the moon, so getting more cargo there is a must.  You could launch a completely dedicated newly designed tug, but you already have a second stage in orbit, why not just fill it and use it as a tug.  It has engines and tanks, instead of burning all the second stages up.  A stretched second stage could be optimized as a tanker to fill a tug adapted second stage.  Lots of second stage possibilities.  Tugs, tankers, habitats, fuel depots etc. 

[Eric Hedman]

I have been thinking about the problem of second stage reuse and ways to achieve cost savings other than going down the current path that SpaceX is attempting with Starship. For smaller vehicles, landing the entire second stage could costly for payload capacity, takes a long time to develop and will make the entire stage a lot more complex.

Since engines tend to be the most costly part of any stage, what if you just recover them! Basically applying ULA's concept of SMART re-use, but for upper stage engine section. That uses a HIAD for entry and decent of just the engine section and a helicopter captures it. The fairings could also be captured in a manner similar to that being used on Falcon 9. Only the second stage propellant tanks are not recovered, which are a small fraction of the cost of the entire vehicle.

While it's not an immaculate solution and would not be as rapidly reusable as Starship promises to be, it could be a good enough interim solution. Returning the booster on a ship already limits how rapidly New Glenn can be reused and the demand for launches in the near term isn't high enough to require such a cadence.

It all depends upon if saving two BE-3U engines on the upper stage is worth it.  The cost of those two engines needs to be compared with the cost of recovering and reusing them.  It starts with the development cost of separating them from the stage, the cost of a heat shield for atmospheric entry, the cost of parachutes and the deployment mechanism, the cost of the recovery equipment, the cost of the recovery operation and the cost of refurbishment.  You would also have to compare it to the possible cost reductions in manufacturing the engines.  Only Blue probably has ballpark figures close enough to make that analysis.  My wild guess is they would be better off looking at cost reductions in manufacturing the engines.

[Alberto-Girardi]

I have been thinking about the problem of second stage reuse and ways to achieve cost savings other than going down the current path that SpaceX is attempting with Starship. For smaller vehicles, landing the entire second stage could costly for payload capacity, takes a long time to develop and will make the entire stage a lot more complex.

Since engines tend to be the most costly part of any stage, what if you just recover them! Basically applying ULA's concept of SMART re-use, but for upper stage engine section. That uses a HIAD for entry and decent of just the engine section and a helicopter captures it. The fairings could also be captured in a manner similar to that being used on Falcon 9. Only the second stage propellant tanks are not recovered, which are a small fraction of the cost of the entire vehicle.

While it's not an immaculate solution and would not be as rapidly reusable as Starship promises to be, it could be a good enough interim solution. Returning the booster on a ship already limits how rapidly New Glenn can be reused and the demand for launches in the near term isn't high enough to require such a cadence.

It all depends upon if saving two BE-3U engines on the upper stage is worth it.  The cost of those two engines needs to be compared with the cost of recovering and reusing them.  It starts with the development cost of separating them from the stage, the cost of a heat shield for atmospheric entry, the cost of parachutes and the deployment mechanism, the cost of the recovery equipment, the cost of the recovery operation and the cost of refurbishment.  You would also have to compare it to the possible cost reductions in manufacturing the engines.  Only Blue probably has ballpark figures close enough to make that analysis.  My wild guess is they would be better off looking at cost reductions in manufacturing the engines.

Great point. The SMART reuse idea isn't that easy: you have to detach plumbing and have an heat shield in the front, you have to be stable(it is difficult because the engines are heavy, but away from the heat shield). Maybe is easier to recover the entire second stage, but i want to try some simple and rough calculations.

[Alberto-Girardi]

The second stage itself would become the space tug.  The cargo for this tug would be say a Canada arm, and possibly a docking port.  Tanker second stages would refuel it.  Then a large payload could be attached, or several large payloads could be attached.  The fully fueled second stage tug would then transport 50-100 tons or more to say lunar orbit.  You don't waste the second stage, but refuel it.  Large single pieces of cargo launched from another New Glenn could then be taken to the moon orbit.  Individually New Glenn can only deliver what? 10-12 tons to the moon.  Refueling a second stage tug would allow much heavier payloads to be delivered to the Artemis orbit.  This idea has been floating around for 15 years or more using distributed launch and refueling to get larger payloads to cis-lunar space. 

Bezo's wants to industrialize the moon, so getting more cargo there is a must.  You could launch a completely dedicated newly designed tug, but you already have a second stage in orbit, why not just fill it and use it as a tug.  It has engines and tanks, instead of burning all the second stages up.  A stretched second stage could be optimized as a tanker to fill a tug adapted second stage.  Lots of second stage possibilities.  Tugs, tankers, habitats, fuel depots etc.

That's intersting, could be very useful. There are difficulties, expecially in the refuiling part, because the LH2 is very cold, and they would need to mantain cryogenics temperatures for long time. I don't see this solution forhte first years, but maybe later...

[joek]

...
Since engines tend to be the most costly part of any stage, what if you just recover them! Basically applying ULA's concept of SMART re-use, but for upper stage engine section. That uses a HIAD for entry and decent of just the engine section and a helicopter captures it. The fairings could also be captured in a manner similar to that being used on Falcon 9. Only the second stage propellant tanks are not recovered, which are a small fraction of the cost of the entire vehicle.

While it's not an immaculate solution and would not be as rapidly reusable as Starship promises to be, it could be a good enough interim solution. Returning the booster on a ship already limits how rapidly New Glenn can be reused and the demand for launches in the near term isn't high enough to require such a cadence.

It all depends upon if saving two BE-3U engines on the upper stage is worth it.  The cost of those two engines needs to be compared with the cost of recovering and reusing them.  It starts with the development cost of separating them from the stage, the cost of a heat shield for atmospheric entry, the cost of parachutes and the deployment mechanism, the cost of the recovery equipment, the cost of the recovery operation and the cost of refurbishment.  You would also have to compare it to the possible cost reductions in manufacturing the engines.  Only Blue probably has ballpark figures close enough to make that analysis.  My wild guess is they would be better off looking at cost reductions in manufacturing the engines.

Good point, as that is where SMART starts to break down.  The more expensive the engines (as related to rest of LV), the more sense SMART makes.

However, as discussed in the old thread, increasing engine cost as a % of LV makes SMART more rational.  Which was one of my primary complaints with SMART (and Dr. Sower's model).  Inflating engine cost benefits SMART but may still result in a non-competitive launcher (Dr. Sowers never responded to that challenge). If you decrease engine cost as % of LV, SMART gets less rational.

In short, given cost projections for, e.g., Raptor, SMART makes little sense.  People still contemplating SMART as a cost-effective solution are at least a decade out of date and attempting to rationalize stupid choices.

[dante2308]

The second stage itself would become the space tug.  The cargo for this tug would be say a Canada arm, and possibly a docking port.  Tanker second stages would refuel it.  Then a large payload could be attached, or several large payloads could be attached.  The fully fueled second stage tug would then transport 50-100 tons or more to say lunar orbit.  You don't waste the second stage, but refuel it.  Large single pieces of cargo launched from another New Glenn could then be taken to the moon orbit.  Individually New Glenn can only deliver what? 10-12 tons to the moon.  Refueling a second stage tug would allow much heavier payloads to be delivered to the Artemis orbit.  This idea has been floating around for 15 years or more using distributed launch and refueling to get larger payloads to cis-lunar space. 

Bezo's wants to industrialize the moon, so getting more cargo there is a must.  You could launch a completely dedicated newly designed tug, but you already have a second stage in orbit, why not just fill it and use it as a tug.  It has engines and tanks, instead of burning all the second stages up.  A stretched second stage could be optimized as a tanker to fill a tug adapted second stage.  Lots of second stage possibilities.  Tugs, tankers, habitats, fuel depots etc.

Refueling and then moving a second stage to the moon with a usable payload and returning it to LEO seems to be an architecture that requires so many refuelings with expendable second stages that I still can't quite detect where the savings can be found. In this scheme, every payload from Earth, including fuel, needs a new second stage, right? Does this throw more mass to the moon than the expended refueling second stages would? As proposed, I would have guessed it would throw less mass.

[spacenut]

Well, this is what ACES was trying to do back about 15 years ago with ULA.  Refueling an ACES stage for in space heavy lifting. 

You can either send five 10 ton payloads to TLI and waste 5 upper stages, when one piece of equipment needed at the moon weighs 50 tons.  OR, you can send the 50 ton payload into orbit with it's second stage still attached.  Then send 4 tanker first stages to deliver fuel, then the full second stage and 50 ton payload has enough fuel to tug it to the moon.  This is essentially what Starship is going to do for Mars.  With this at least one stage is reused delivering a heavy payload.   

[dante2308]

Well, this is what ACES was trying to do back about 15 years ago with ULA.  Refueling an ACES stage for in space heavy lifting. 

You can either send five 10 ton payloads to TLI and waste 5 upper stages, when one piece of equipment needed at the moon weighs 50 tons.  OR, you can send the 50 ton payload into orbit with it's second stage still attached.  Then send 4 tanker first stages to deliver fuel, then the full second stage and 50 ton payload has enough fuel to tug it to the moon.  This is essentially what Starship is going to do for Mars.  With this at least one stage is reused delivering a heavy payload.   

Except the word tug implies that the second stage returns to Earth which would mean that far less than 50 tons gets to the moon. I suppose if you end up expending everything, then you come out just a tag bit ahead. But that's not really reuse.

I think a key difference with Starship is that you technically only ever need to build two Starships to do anything. At that point, you are fairly free to waste all the fuel you like. The savings are dramatically different so the reasoning sort of changes. That and the fact that Starship is a super heavy lifter to begin with.

[Alberto-Girardi]

Developing a so complex (but very interstinfg and useful) in orbit second stage refueling system would be expensive, and I think that  if not stimulated by Nasa they won't do this, becaus this system could serve only a few of today costumers better than what is done today (obviusly not by New Glenn, but by other rockets ).  Maybe the HLS delivery to Moon orbit could push BO to develope this.

[spacenut]

Making second stages into tugs, even if they don't return to earth, refueling in space, having fuel depots, etc., is going to have to happen one way or another to have any kind of cis lunar program, or Mars program, or anything in deep space.  It doesn't matter about customers.  Look at SpaceX, they want to go to Mars.  They are spending money building Starship/Superheavy to get there.  They are going to do in space refueling, etc. 

Even the Artemis program will have to take fuel to the moon for the landers and the Artemis station keeping.  So, either you have to have large second stages and larger rockets, or in space refueling to carry large objects, cargo, landers, etc. to the moon.  New Glenn alone may not do it.  Being able to refuel a New Glenn upper stage with a large lander, cargo, or fuel for the lunar program will require refueling an upper stage at some point.  Blue has the money, why not develop a space tug out of the second stage.  The BE-3 engine can be throttled from 30-100 thousand lbs thrust.  (13mt to 45mt thrust), so it can deliver, slow down get into proper orbit, dock, and deliver whatever is needed.  Also, if it has enough fuel left, can return to earth for more.  This upper stage on New Glenn has a lot of possibilities, great engines, and large size.  It could also be stretched for a tanker to deliver a lot of fuel. 

[Alberto-Girardi]

Making second stages into tugs, even if they don't return to earth, refueling in space, having fuel depots, etc., is going to have to happen one way or another to have any kind of cis lunar program, or Mars program, or anything in deep space.  It doesn't matter about customers.  Look at SpaceX, they want to go to Mars.  They are spending money building Starship/Superheavy to get there.  They are going to do in space refueling, etc. 

Even the Artemis program will have to take fuel to the moon for the landers and the Artemis station keeping.  So, either you have to have large second stages and larger rockets, or in space refueling to carry large objects, cargo, landers, etc. to the moon.  New Glenn alone may not do it.  Being able to refuel a New Glenn upper stage with a large lander, cargo, or fuel for the lunar program will require refueling an upper stage at some point.  Blue has the money, why not develop a space tug out of the second stage.  The BE-3 engine can be throttled from 30-100 thousand lbs thrust.  (13mt to 45mt thrust), so it can deliver, slow down get into proper orbit, dock, and deliver whatever is needed.  Also, if it has enough fuel left, can return to earth for more.  This upper stage on New Glenn has a lot of possibilities, great engines, and large size.  It could also be stretched for a tanker to deliver a lot of fuel.

Yes, IMO you are completely right. What I was saying is that I hope that Artemis program will accelerate this development (and  there you need political governament vision, but I won't talk about this). But normal costumers are not much intersted in second stage refueling. So there the dream of Musk (to colonize mars) and Bezos (to colonize space) are important, otherwise there isn't innovation.

Talking about potential space tug with second stage: it will need both energy and cooling. Docking technique will be needed, but in modern days with computer should not be too complicated (I men). But I think that  the physical docking systemm won't bee to easy tobuild, because, if they dock from the sides (IMO is the best option) you have to build a very small volume system. So IDK if solution like soft capture (to connect the spececrafts to further close the distance) and then hard capture to provide strong connection, and transfer propellant are possible, maybe yes but is complicated.

They will also need to develop a streched versoìion of the upper stage, to carry only propellant or a small payload, but is relatively easy.

[spacenut]

SpaceX is building the DragonX which is basically a 2nd stage with docking adapter, small habitat, no large engine, but smaller thrusters, solar panels, etc. 

The New Glenn upper stage is a lot larger, thus you could do even more with it.  Docking can be done various ways.  SpaceX already is good at Docking with the Dragon adapter.  They are planning to dock Starships end to end to refuel.  Shouldn't be too hard for Blue Origin to do. 

Bezos has spent billions on his launch facility and a manufacturing building in Florida.  He has also spent a lot building a rocket engine factory in Huntsville, Ala.  So, once all this is done, he can spend billions on "in space" hardware, like refueling, tugs, moon landers, etc. 

[TrevorMonty]

For near future NG 2nd is just too big to be used as space tug, would take too many launches to refuel, in between those launches there is boiloff losses. Better to use smaller Be7 powered dedicated tanker that can be refuelled with single NG launch. NGIS are developing this BE7 powered tanker its called Transfer Element. They have systems in place to reduce boiloff while in deep space.

Hopefully long term we will be creating 1000s tonnes of hydrolox from lunar and asteriod water, then we'll need larger Be3 tanker.



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[trimeta]

When it comes to refuelable space tugs, to me there's a huge difference between "we have a specific mission for which we'll launch N times, once with payload and N-1 times to refuel the second stage attached to that payload, so it can then perform some massive burn" and "we're going to just leave our second stage in orbit and hope that eventually we get a mission where it makes sense to refuel it and reuse it." The former case, which is what Starship is doing, means you know how long the second stages need to survive idling in orbit, you know exactly what orbits you need to target, and you can synchronize things to use the exact necessary amount of fuel.

The latter case feels like it's ignoring that "Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is." Unless subsequent missions happen to be going exactly where the tug already is, it seems that the delta-v to align with the tug isn't worth what you can get by exploiting in-space hardware. Plus, your new mission has its own second stage it could use. Unless you're launching a bunch of times, with some of those launches having no payload so they can carry extra fuel, it doesn't seem like it's worth it.

[Alberto-Girardi]

For near future NG 2nd is just too big to be used as space tug, would take too many launches to refuel, in between those launches there is boiloff losses. Better to use smaller Be7 powered dedicated tanker that can be refuelled with single NG launch. NGIS are developing this BE7 powered tanker its called Transfer Element. They have systems in place to reduce boiloff while in deep space.

Hopefully long term we will be creating 1000s tonnes of hydrolox from lunar and asteriod water, then we'll need larger Be3 tanker.



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Yes, in near future thi won't happen. Why would they need to refuel the stage completely? I really hope that this kinfd of projects are persued by BO, because Starship is very good, but runs on methane (and oxygen). That is good for mars, but not for the Moon, wher with ISRU is easier to extract Hydrolox. SO a space infrastructure based on H₂ /O₂ is good. Is even better to have two different infrastructures, so if one fails there is the other.