Author Topic: Starship On-orbit refueling - Options and Discussion  (Read 597065 times)

Offline meekGee

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #120 on: 07/27/2020 02:15 pm »




Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?


At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...
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Re: Starship In-orbit refueling - Options and Discussion
« Reply #121 on: 07/27/2020 02:17 pm »
For me (IANARS or E) is the active cooling (and it's energy requirements) for sub-cooling the O2 and CH4.  Yes, the issue exists at the ISRU production for return, but it also seems likely to be required for the propellent accumulation before TMI.

Transfer is part of the issue, though the pressure gradient discussion in OP is enlightening.  But accomplishing and maintaining the subcooling densification will require something more than just venting gas, I would think.
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Offline spacenut

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #122 on: 07/27/2020 02:27 pm »
My idea is not to have a crew in an outbound for Mars Starship waiting and having to have 6 tankers dock and transfer fuel.

My idea is to put tankers in orbit with refrigeration equipment and some solar panels for power.  Then fill the tankers with other tankers.  Then the outbound crewed ship can dock only once to a full tanker and then go. 

So essentially orbital tankers will become fuel depots for only one stop and fill to go per Starship.  Orbital tankers can be filled at reasonable pace during the off synods.  Then you have several full orbital tankers that can be used for any outbound Starships to the moon or Mars.  SpaceX could also let others license their technology to fill tankers with their rockets for a mission they want to do in deep space. 

For massive flotillas of Starships bound for Mars colony during the 6 month synod when Mars is closest to earth, fuel depots of some sort is the only way to save time.  Using Starship tankers would be easy without building anything new.   Starship will be a do-all spacecraft.  Tanker, fuel depot, moon lander, Mars lander, satellite orbiter, cargo carrier.  Modified for whatever is needed. 

Offline cdebuhr

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #123 on: 07/27/2020 02:37 pm »
For me (IANARS or E) is the active cooling (and it's energy requirements) for sub-cooling the O2 and CH4.  Yes, the issue exists at the ISRU production for return, but it also seems likely to be required for the propellent accumulation before TMI.

Transfer is part of the issue, though the pressure gradient discussion in OP is enlightening.  But accomplishing and maintaining the subcooling densification will require something more than just venting gas, I would think.
As I understand it (if I understand it ...), the purpose of prop densification is to get more prop in the tanks to help with the very difficult task of getting out of the lower bits of Earth's relatively deep gravity well.  Do we really think they're going to be using densified props for TMI, or Mars ascent?  I had always assumed sub-cooling would be a getting-off-of-Earth thing, and otherwise props would be run of the mill (i.e., at the tank pressure determined  boiling point) cryogens.  Is Raptor so finely tuned that it requires sub-cooled prop, or is sub-cooling just used for a needed performance boost?  I had always assumed the latter.  My own (totally uninformed) speculation is that sub-cooling is a total non-issue for on-orbit prop transfer.

Offline Star-Dust

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #124 on: 07/27/2020 02:51 pm »




Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.

Offline meekGee

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #125 on: 07/27/2020 02:58 pm »




Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.
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Offline whitelancer64

Re: Starship In-orbit refueling - Options and Discussion
« Reply #126 on: 07/27/2020 03:06 pm »
My idea is not to have a crew in an outbound for Mars Starship waiting and having to have 6 tankers dock and transfer fuel.

My idea is to put tankers in orbit with refrigeration equipment and some solar panels for power.  Then fill the tankers with other tankers.  Then the outbound crewed ship can dock only once to a full tanker and then go. 

So essentially orbital tankers will become fuel depots for only one stop and fill to go per Starship.  Orbital tankers can be filled at reasonable pace during the off synods.  Then you have several full orbital tankers that can be used for any outbound Starships to the moon or Mars.  SpaceX could also let others license their technology to fill tankers with their rockets for a mission they want to do in deep space. 

For massive flotillas of Starships bound for Mars colony during the 6 month synod when Mars is closest to earth, fuel depots of some sort is the only way to save time.  Using Starship tankers would be easy without building anything new.   Starship will be a do-all spacecraft.  Tanker, fuel depot, moon lander, Mars lander, satellite orbiter, cargo carrier.  Modified for whatever is needed.

Was there someone suggesting they would launch crew first? That's entirely backwards.

I am pretty sure that using tankers as temporary fuel depots is already SpaceX's plan.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Star-Dust

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #127 on: 07/27/2020 03:09 pm »




Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..
« Last Edit: 07/27/2020 03:11 pm by Star-Dust »

Offline Robotbeat

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #128 on: 07/27/2020 03:10 pm »
Just here to point out that the Shuttle External Tank cost $75 million, for a launch vehicle whose total payload is about 20-27 tonnes to LEO. And doesn’t last long in LEO due in part to popcorning of the insulation. Drop tanks are much too expensive except for maybe specialized missions. It’s not much different from just being totally expendable...
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Offline whitelancer64

Re: Starship In-orbit refueling - Options and Discussion
« Reply #129 on: 07/27/2020 03:13 pm »
Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..

Why does there have to be an interim solution?
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Star-Dust

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #130 on: 07/27/2020 03:16 pm »
Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..

Why does there have to be an interim solution?

Because time is ticking and SX plans are too ambitiuos (IMHO) for the timeframe, and it's like a black hole money siphoning endeavor.
« Last Edit: 07/27/2020 03:19 pm by Star-Dust »

Offline meekGee

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #131 on: 07/27/2020 03:18 pm »




Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..
Why do you think that after figuring how to build a reusable heavy launcher, orbital fueling will be any sort of issue, or an issue big enough to warrant something as problematic for reuse as an external tank?
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Re: Starship In-orbit refueling - Options and Discussion
« Reply #132 on: 07/27/2020 03:24 pm »
Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..

Why does there have to be an interim solution?

Because time is ticking and SX plans are too ambitiuos (IMHO) for the timeframe, and it's like a black hole money siphoning endeavor.
Source? Or just for throwing shade at SpaceX instead of refueling technique discussion?

You are at it again, dedicated expensive lander, and now this?
« Last Edit: 07/27/2020 03:32 pm by Alvian@IDN »
My parents was just being born when the Apollo program is over. Why we are still stuck in this stagnation, let's go forward again

Offline Star-Dust

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #133 on: 07/27/2020 03:27 pm »




Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..
Why do you think that after figuring how to build a reusable heavy launcher, orbital fueling will be any sort of issue, or an issue big enough to warrant something as problematic for reuse as an external tank?

You certainly mean theorically figuring how, but in practice and in a financially viable manner I dont think so.

Alvian@IDN
Quote
Source? Or just for throwing shade at SpaceX instead of refueling technique discussion?

You are at it again

I made my point of view considering NASA R&D progress on the matter (orbital refuelling).
« Last Edit: 07/27/2020 03:30 pm by Star-Dust »

Offline whitelancer64

Re: Starship In-orbit refueling - Options and Discussion
« Reply #134 on: 07/27/2020 03:27 pm »
Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..

Why does there have to be an interim solution?

Because time is ticking and SX plans are too ambitiuos (IMHO) for the timeframe, and it's like a black hole money siphoning endeavor.

If "time is ticking" and money is short, then the last thing they'd want to be doing is working on a more complicated solution to the problem that also requires more money for development, hardware fabrication, tooling, etc.
« Last Edit: 07/27/2020 03:28 pm by whitelancer64 »
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Robotbeat

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #135 on: 07/27/2020 03:54 pm »
Starship already needs to be refueled on Mars for return.

If you want to get started and send equipment or even people to Mars one-way and you don’t care about the cost to do it, Red Dragon on falcon Heavy would work. They’d have to pay for finishing the powered landing capability development for Dragon plus probably a Dragon XL module for habitable space on the way there, but it’d work.

But it’s orders of magnitude more expensive per kg to Mars. It’s wasting precious capital (including human capital, which may be rarer than financial capital) and time on a dead end that nonetheless is risky.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline steveleach

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #136 on: 07/27/2020 03:58 pm »
Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..

Why does there have to be an interim solution?

Because time is ticking and SX plans are too ambitiuos (IMHO) for the timeframe, and it's like a black hole money siphoning endeavor.
I can't tell whether this is a troll, some strange sort of irony, or just a really uninformed but serious suggestion.

The idea is to launch a tank (pretty much a Starship with most bits thrown away somehow) and then dock with that, connect plumbing, and keep it attached for propellant transfer during the trans-Mars burn, yes?

And the justification is that it is simpler than launching another Starship, docking, connecting plumbing, transferring the propellant and then undocking?

Am I missing something here?

Offline rsnellenberger

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #137 on: 07/27/2020 06:09 pm »
Refueling Starship on orbit requires an automated/robotic umbilical connection mechanism. It can be more robustly built and complex than a “standard” rocket umbilical, since it’s going into a large, reusable vehicle. It also probably wants to be androgynous, since Starships will be refueling back-to-back.

My thought is - once they’ve developed that androgynous, automated refueling mechanism, why wouldn’t SpaceX use that same mechanism everywhere it applies?  Pad umbilicals & SH tanking umbilicals, SH-Starship tanking umbilicals, Starship-Starship refueling umbilicals, MarsPort pad umbilicals - the works. One added benefit would be that they’d be testing the bejeezus out of the mechanism every time they tanked or flew one of the vehicles.

Another benefit would be that they could move away from having time-critical T-0 umbilicals. Once the vehicle is in the final count and the tanks are pressurizing for flight (T-30-ish), disconnect and retract the umbilicals into a protective housing. If the launch is aborted, the umbilicals just hook themselves back up. 

Offline philw1776

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #138 on: 07/27/2020 07:05 pm »
Interesting but seems very very complexe,to add to the difficulty this will have to be done 5 times to get to Mars....................can't we just attach an external tank like for space shuttle?

At work I outlawed the use of the words "just" and "simply" when proposing alternative ideas.

You're not allowed to grade your own work...

You're right to point out to the vocabulary it might be deceiving, for me "Just" and "simply" means proven technology have been in use for a while.
"Complexe" means that it's at the early stages of concept has to be put in practice in reliable manner.
So..  it's proven to be prohibitively expensive?
 
Starship is anything but a Shuttle repeat.  It's the anti-shuttle.  Consider each element in isolation, fine, but certainly don't give it points just because it was used in shuttle..

Remember Starship has to land on Mars and take off again, then re-enter Earth.  Are you "just" going to keep docking with new tanks all the time and throwing them away afterwards?

Refueling is fundamental to any mode of transportation, and compared to other challenges like, say, launch and EDL, it's relatively easy.

I'm from those who consider Starship as a mean to get to Mars and beyond, the primary goal is to get to Mars, getting it cheap getting it reausable getting it through re-fueling or external tanks, this is for me a secondary issue that could be worked out, it must be some interim solution to get to Mars, but to get it in the 2030's IMHO we must get some compromises..

Why does there have to be an interim solution?

Because time is ticking and SX plans are too ambitiuos (IMHO) for the timeframe, and it's like a black hole money siphoning endeavor.

Yet another thread disguised as SpaceX plans for X that is in reality "My alternative architecture because SpaceX is on a track to fail"
FULL SEND!!!!

Offline Vanspace

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Re: Starship In-orbit refueling - Options and Discussion
« Reply #139 on: 07/27/2020 08:33 pm »
I have been wondering about the capabilities of the anti-boiloff systems. For Mars ISRU the last step is to condense the gases to liquid.

Can the anti-boiloff system on the now empty landed Starships be fed gaseous propellants and condense them down?

If it can, that saves a bunch of payload. If it can't is there a simple pre-stage like cooling or compressing that will help?

If the androgynous GSE adapter also has the vent lines can those be used to feed gaseous propellants to the anti-boiloff system?
"p can not equal zero" is the only scientific Truth. I could be wrong (p<0.05)

Tags: HLS 
 

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