Question SpaceX Super Heavy launching fuel pods

[Mycropht]

SpaceX is planning Starship tankers but it seems to me that quite a lot of mass is going up and down for a sake of full reusability. Now, I am very interested in the subject, but my knowledge is lacking.

With help of Claude AI , I was thinking of a Super Heavy launching not a Starship tanker, but a fuel pod carrier.

It would go like this:

A standard Super Heavy launches with a two-parts fuel pod:

• Carrier section with engines, powered enough to provide maneuvering, acceptable speed and altitude for a suborbital randezvous. Ideally recovered, maybe Falcon 9 fairing style.
• Fuel pod/tank section with grabbing points and minimal thermal protection. The pod is full, to minimize sloshing, with either methane or LOX.

An orbit-only Starship variant dives from the orbit and grabs the fuel pod which separates from the carrier section. The fuel is not transferred, but the complete pod is lifted to orbit with the Starship, with the fuel to be transferred later. The fuel pod is discarded and burns in orbit.

• I believe quite some weight could be stripped from the Starship if it is orbit-only, but some other parts must be added like the grabbing mechanism, and radiators for prolonged stay in orbit.

Now, I have no idea if it is feasible for the fuel pod and the diving Starship to match altitude and velocity with constraints that nothing should burn or crash and that the Starship should returns to a stable orbit with enough fuel in the tank so the whole operation makes sense. Also, that the risks involved are acceptable.

I would appreciate it if someone who knows more about this could tell me if the idea is completely stupid and, if so, why. I am not suggestion that it should be done that way, this is just playing with an idea.

 

[fj.torres]

Not stupid.
It's a safe bet the SPACEX staff are keeping an eye out for Starship derivative concepts. We'll see which way they go.

in the meantime check this orbital fuel depot concept:

View: https://m.youtube.com/watch?v=T9EFqPcoTwU


A variant of this can be used to establish a chair of fuel stations in LEO, GEO, LUNAR ORBIT, LAGRANGE POINTS, and even MARS ORBIT. The MARS depot could be refueled from mars surface and serve for asteroid belt and outer planet unmanned exploration buses.

The key question is how long the depot can be powered to refrigerate the fuel so the fuel can be available when needed. Days? Weeks? Months? Years, maybe?

It would held deep space projects if the Starship can leave for its mission fully fueled well above the gravity well.

Some proposed concepts start with a central Starship derived core and add even more capacity with extra modules, think of storing enough fuel for multiple ship missions.

 

[Mycropht]

Thanks a lot for the answer and the interesting video!

Fuel is problematic. Some kind of orbital fuel station is definitely needed, as the Starship story progresses. In case of fuel coming from Earth, I was trying to find a more cost effective way then a Starship delivering it to orbit. Eventually, I believe nuclear propulsion will enter the picture, unless we get some Star Trek methods of pushing starships.

 

[fj.torres]

Thanks a lot for the answer and the interesting video!

Fuel is problematic. Some kind of orbital fuel station is definitely needed, as the Starship story progresses. In case of fuel coming from Earth, I was trying to find a more cost effective way then a Starship delivering it to orbit. Eventually, I believe nuclear propulsion will enter the picture, unless we get some Star Trek methods of pushing starships.

A form of nuclear will arrive...
...someday.
But first you have to get the drive off the mudball. And it won't be light.
The same problem exists for fuel.

Chemical is unavoidable for the next 20-30 years. There might be variations of how to loft the orbital vehicle but in the end they'll be using chemical to reach orbit.

Btw, that site has several other concepts of things that can be done with the Starship launch system. Some are promising.

Personally, I don't give too much thought to Mars. I'm more interested in the impact to near Earth space between LEO, the Moon, the Lagrangians, and the Trojans. That will be revolutionary enough.

 

[Romaclanahan]

The Starship Tanker concept, proposed by SpaceX, is designed to be a reliable and efficient method for refueling Starship spacecraft in orbit. While no system is completely fail-proof, the Starship Tanker concept has several features that make it highly robust and resilient.

Firstly, the tanker itself is essentially a stripped-down version of the Starship spacecraft, which means it can leverage the extensive testing and validation that the main Starship program undergoes. This reduces the risk of unforeseen issues with the tanker's systems.

Secondly, the refueling process is designed to be relatively simple and autonomous, minimizing the potential for human error. The tanker would dock with the target Starship using a combination of automated navigation systems and precision docking mechanisms.

Thirdly, in case of an emergency or malfunction during refueling, both spacecraft are equipped with multiple redundancies in critical systems such as life support, power generation, and propulsion. This ensures that even if something goes wrong during refueling, both vehicles can safely separate and recover.

Lastly, SpaceX's approach to iterative design and testing allows for rapid identification and correction of any issues that may arise during development or operation of the Starship Tanker. This agile development methodology helps mitigate risks by continuously validating assumptions against real-world performance data.

While it's impossible to eliminate all potential failure modes entirely, SpaceX's focus on simplicity, autonomy, redundancy, and continuous iteration makes the Starship Tanker concept highly reliable. As with any complex engineering project, however, success will ultimately depend on rigorous testing and validation to ensure that all components work together seamlessly in various scenarios.

I fully support the tanker design.