Multi-Ship Expeditions, Starboat & Starship, Other.

Void · 2025-11-15 09:05:49

As always, I have the potential to be wrong.

I have been thinking about an "Upstairs Starship". This would be a Starship which typically does not land on the Earth but maybe at times might land on the Moon.

I am thinking that it would be made of "Ferroaluminum": https://en.wikipedia.org/wiki/Ferroaluminum

The Melting point would be 1250 C, I think, which is lower than Stainless Steel. But it is corrosion resistant.

It would have less weight and less inertia. So aerobraking to aerocapture might be possible. Of course, it would have to be refilled by a "Standard Starship".

The objective would normally be to not dive too deep into the atmosphere before skipping off, to keep peak heating down.

But it would not be forbidden to have supplemental protections such as tiles and active cooling. It might be possible to have ports in the belly what would allow fluids to be injected under the belly. Ideally this cooling method could also be used in navigation though the atmosphere.

The purpose of a machine like this would be to take possession of a package from a "Standard Starship" and bring it to a higher orbit.

This would probably be for freight.

It is possible that it could be in association with a Electric Rocket System.

This then would be a intermediary between a "Standard Starship", and an Electric Rocket System.

So, the "Standard Starship" might refill it with Methane and Oxygen but also perhaps an Argon/Xenon mix. The Electric Rocket System with large solar panels staying out of the atmosphere even at very high altitude would provide shade and cooling power to keep the boil-off problem under control.

Perhaps the Electric Rocket System, would not go as low as the ISS is to reduce drag. (Perhaps).

The "Upstairs Starship", then being linked to the Electric Rocket System could as a hybrid travel to an orbit of the Moon. To come back, the combination might separate at some point so that the "Upstairs Starship" could use air braking to get it down to take payload from a "Standard Starship".

And of course I am hoping that eventually the Electric Rocket System could be switched to a metal propellant such as Neumann Drive or Magdrive might allow.

In that case, refilling could be done at the Moon orbit. Both Metals propellants, and Oxygen.

Ending Pending

Last edited by Void (2025-11-15 09:22:19)

Void · 2025-11-15 10:31:02

https://www.bing.com/videos/riverview/r … &FORM=VIRE Quote:

SpaceX Revealed Starship-Dragon Combination Plan to Reach the Moon Faster than China & BO…
YouTube
GREAT SPACEX
44 views

I think it makes sense to separate the Lunar Space Station effort from the Moon Landing Effort.

Perhaps later then the two could be joined in some way.

In reference to my just prior post here, I am thinking that in the deep future, a "Upstairs Starship" might have its engines in its belly. This would allow it to fire its engines during aerobraking to protect it's belly from excess heat. The engines should be desired to be allowed to fire a reduced temperature mix, such as 90% Methane/10% Oxygen.

But when properly used, it may not be a problem to use the engines to travel towards the Moon, when in a vacuum.

Engines being in the belly, then they would also be suitable for landing on the Moon.

To get this thing to orbit it may need raptors in its tail, but upon reaching orbit those could be removed partially or entirely.

My notion is that this ship would not land on Earth ever again but might do repeated skips on the Earth's atmosphere. As this would take time, so a capsule return of crew would be appropriate.

Having a Starship escort a capsule both to and from the Moon, would give the capsule additional protections such as radiation protection in many cases.

Ending Pending

Last edited by Void (2025-11-15 10:38:41)

Void · Today 09:13:46

This video talks about a supersized V4 Starship, and towards the end, Starboat (Mini-Starship): https://www.bing.com/videos/riverview/r … ORM=VAMGZC Quote:

Elon Musk Revealed Big Upgrade on Starship V4 Shocked NASA!
YouTube
TECH MAP
1 views

Starship>200 Tons Payload in reusable mode.

The blurb about Starboat is especially interesting to me. More or less an optional 3rd stage for the Starship system.

-Could be lifted to LEO fully filled with propellants by one Starship.

-Payload to Mars 5-25 Tons?

-2200 km point to point on Mars. (Using 100 tons of propellants)

-50-120 tons of propellants to get back to Earth.

-1/5th as heavy as a Starship.

Ending Pending

Last edited by Void (Today 09:28:24)

Void · Today 11:14:53

This post relates to the just previous post about Starship V4 and Starboat.

I may have a notion worth at least a look, which may make Starboat a much better option.

I think that if Starboat goes to Mars from LEO, it should be accompanied by a full Starship, landing only.

That is no intention to relaunch the full Starship. So, if the two were docked together in transit, this would greatly increase the comfort and safety of the travelers. Radiation protection may be better as you can impose the bulk of the full starship between the sun and the humans. The major Starship then can become part of a Mars infrastructure upon landing.

The above is all contemplated already.

If we had the assets for it, we might station a full Starship in orbit, to then accompany the Starboat back to Earth to offer similar protections and comforts. But unfortunately it is difficult to stop a Starship in orbit of Mars, and otherwise you end up refilling a whole Starship on the surface of Mars which is a burden we wish to avoid by doing a Starboat in the first place.

But I recalled a "Free Return" which could be used in the event that a mission to Mars had to be aborted prior to landing on Mars.

https://en.wikipedia.org/wiki/Free-return_trajectory

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Free-return trajectory
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Sketch of a circumlunar free return trajectory (not to scale), plotted on the rotating reference frame rotating with the moon. (Moon's motion only shown for clarity)
In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to return to the primary body without propulsion (hence the term free).[1]
Many free-return trajectories are designed to intersect the atmosphere; however, periodic versions exist which pass the moon and Earth at constant periapsis, which have been proposed for cyclers.
Earth–Moon
The first spacecraft to use a free-return trajectory was the Soviet Luna 3 mission in October 1959. It used the Moon's gravity to send it back towards the Earth so that the photographs it had taken of the far side of the Moon could be downloaded by radio.
Symmetrical free-return trajectories were studied by Arthur Schwaniger of NASA in 1963 with reference to the Earth–Moon system.[2] He studied cases in which the trajectory at some point crosses at a right angle the line going through the center of the Earth and the center of the Moon, and also cases in which the trajectory crosses at a right angle the plane containing that line and perpendicular to the plane of the Moon's orbit. In both scenarios we can distinguish between:[2]
A circumlunar free-return trajectory around the Moon. The spacecraft passes behind the Moon. It moves there in a direction opposite to that of the Moon, or at least slower than the Moon in the same direction. If the craft's orbit begins in a normal (west to east) direction near Earth, then it makes a figure 8 around the Earth and Moon when plotted in a coordinate system that rotates as the Moon goes around the Earth.
A cislunar free-return trajectory. The spacecraft goes beyond the orbit of the Moon, returns to inside the Moon's orbit, moves in front of the Moon while being diverted by the Moon's gravity to a path away from the Earth to beyond the orbit of the Moon again, and is drawn back to Earth by Earth's gravity. (There is no real distinction between these trajectories and similar ones that never go beyond the Moon's orbit, but the latter may not get very close to the Moon, so are not considered as relevant.)
In both the circumlunar case and the cislunar case, the craft can be moving generally from west to east around the Earth (co-rotational), or from east to west (counter-rotational).
For trajectories in the plane of the Moon's orbit with small periselenum radius (close approach of the Moon), the flight time for a cislunar free-return trajectory is longer than for the circumlunar free-return trajectory with the same periselenum radius. Flight time for a cislunar free-return trajectory decreases with increasing periselenum radius, while flight time for a circumlunar free-return trajectory increases with periselenum radius.[2]
The speed at a perigee of 6555 km from the centre of the Earth for trajectories passing between 2000 and 20 000 km from the Moon is between 10.84 and 10.92 km/s regardless of whether the trajectory is cislunar or circumlunar or whether it is co-rotational or counter-rotational.[3]
Using the simplified model where the orbit of the Moon around the Earth is circular, Schwaniger found that there exists a free-return trajectory in the plane of the orbit of the Moon which is periodic. After returning to low altitude above the Earth (the perigee radius is a parameter, typically 6555 km) the spacecraft would start over on the same trajectory. This periodic trajectory is counter-rotational (it goes from east to west when near the Earth). It has a period of about 650 hours (compare with a sidereal month, which is 655.7 hours, or 27.3 days). Considering the trajectory in an inertial (non-rotating) frame of reference, the perigee occurs directly under the Moon when the Moon is on one side of the Earth. Speed at perigee is about 10.91 km/s. After 3 days it reaches the Moon's orbit, but now more or less on the opposite side of the Earth from the Moon. After a few more days, the craft reaches its (first) apogee and begins to fall back toward the Earth, but as it approaches the Moon's orbit, the Moon arrives, and there is a gravitational interaction. The craft passes on the near side of the Moon at a radius of 2150 km (410 km above the surface) and is thrown back outwards, where it reaches a second apogee. It then falls back toward the Earth, goes around to the other side, and goes through another perigee close to where the first perigee had taken place. By this time the Moon has moved almost half an orbit and is again directly over the craft at perigee. Other cislunar trajectories are similar but do not end up in the same situation as at the beginning, so cannot repeat.[2]
There will of course be similar trajectories with periods of about two sidereal months, three sidereal months, and so on. In each case, the two apogees will be further and further away from Earth. These were not considered by Schwaniger.
This kind of trajectory can occur for similar three-body problems. The problem is an example of a circular restricted three-body problem.
While in a true free-return trajectory no propulsion is applied, in practice there may be small mid-course corrections or other maneuvers.
A free-return trajectory may be the initial trajectory to allow a safe return in the event of a systems failure; this was applied in the Apollo 8, Apollo 10, and Apollo 11 lunar missions. In such a case a free return to a suitable reentry situation is more useful than returning to near the Earth, but then needing propulsion anyway to prevent moving away from it again. Since all went well, these Apollo missions did not have to take advantage of the free return and inserted into orbit upon arrival at the Moon. The atmospheric entry interface velocity upon return from the Moon is approximately 36,500 ft/s (11.1 km/s; 40,100 km/h; 24,900 mph)[4] whereas the more common spacecraft return velocity from low Earth orbit (LEO) is approximately 7.8 km/s (28,000 km/h; 17,000 mph).
Due to the lunar landing site restrictions that resulted from constraining the launch to a free return that flew by the Moon, subsequent Apollo missions, starting with Apollo 12 and including the ill-fated Apollo 13, used a hybrid trajectory that launched to a highly elliptical Earth orbit that fell short of the Moon with effectively a free return to the atmospheric entry corridor. They then performed a mid-course maneuver to change to a trans-Lunar trajectory that was not a free return.[5] This retained the safety characteristics of being on a free return upon launch and only departed from free return once the systems were checked out and the lunar module was docked with the command module, providing back-up maneuver capabilities.[6] In fact, within hours after the accident, Apollo 13 used the lunar module to maneuver from its planned trajectory to a circumlunar free-return trajectory.[7] Apollo 13 was the only Apollo mission to actually turn around the Moon in a free-return trajectory (however, two hours after perilune, propulsion was applied to speed the return to Earth by 10 hours and move the landing spot from the Indian Ocean to the Pacific Ocean).
Earth–Mars
A free-return transfer orbit to Mars is also possible. As with the Moon, this option is mostly considered for crewed missions. Robert Zubrin, in his book The Case for Mars, discusses various trajectories to Mars for his mission design Mars Direct. The Hohmann transfer orbit can be made free-return. It takes 250 days (0.68 years) in the transit to Mars, and in the case of a free-return style abort without the use of propulsion at Mars, 1.5 years to get back to Earth, at a total delta-v requirement of 3.34 km/s. Zubrin advocates a slightly faster transfer, that takes only 180 days to Mars, but 2 years back to Earth in case of an abort. This route comes also at the cost of a higher delta-v of 5.08 km/s. Zubrin writes that faster routes have a significantly higher delta-v cost and free-return duration (e.g. transfer to Mars in 130 days takes 7.93 km/s delta-v and 4 years on the free return), and so he advocates for the 180-day transfer.[8] A free return is also the part of various other mission designs, such as Mars Semi-Direct and Inspiration Mars.
There also exists the option of two- or three-year free-returns that do not rely on the gravity of Mars, but are simply transfer orbits with periods of 2 or 1.5 years, respectively. A two-year free return means from Earth to Mars (aborted there) and then back to Earth all in 2 years.[9] The entry corridor (range of permissible path angles) for landing on Mars is limited, and experience has shown that the path angle is hard to fix (e.g. +/- 0.5 deg). This limits entry into the atmosphere to less than 9 km/s. On this assumption, a two-year return is not possible for some years, and for some years a delta-v kick of 0.6 to 2.7 km/s at Mars may be needed to get back to Earth.[10]
NASA published the Design Reference Architecture 5.0 for Mars in 2009, advocating a 174-day transfer to Mars, which is close to Zubrin's proposed trajectory.[11] It cites a delta-v requirement of approximately 4 km/s for the trans-Mars injection, but does not mention the duration of a free return to Earth.

So, with a relatively passive free return, the Starboat might need to launch from Mars orbit to meet up with a full Starship that is on a 2 year free return loop around Mars. That would doom them to 1.5 years though to get back to Earth.

But if the Free Return Full Starship were bent, by using an Oberth maneuver while passing by Mars, perhaps the trip back to Earth could be modified to be more survivable.

This could be important if it is discovered that some artificial gravity could help human health maintenance a great deal. A coupled Starship and Starboat might give that synthetic gravity.

So, a "Mars Oberth Starship" could swing by Mars and I hope that a Starboat could align with it for a return to Earth.

Of course, if the Starboat ends up alone because of a failure of the "Mars Oberth Starship". The return to Earth could be rather desperate, and marginal in hopes for success. But if the two can meet on a path back to Earth the inhabitants of the Starboat would have a potentially much more favorable transit situation.

The risks are approximately similar to the risks of using a Cycling Spaceship. But you would know before you launched from Mars if the Full Starship was on it's way and if it seemed to be functional during the Oberth burn. You might be able to abort the launch of the Starboat, if the Oberth burn did not go as required.

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The Oberth effect is a phenomenon in rocketry that describes how a spacecraft can achieve greater efficiency and speed when its engines are fired at high speeds, particularly during maneuvers near a gravitational body.
Definition and Explanation
The Oberth effect is named after the German physicist Hermann Oberth, who first described it in the early 20th century. It states that a rocket or spacecraft generates more kinetic energy when it fires its engines at high speeds compared to when it does so at lower speeds. This increased efficiency occurs because the kinetic energy (KE) of an object is proportional to the square of its velocity, as expressed in the formula $KE = \frac{1}{2} mv\^2$, where
m
m is mass and
v
v is velocity.
Wikipedia
+1
How It Works
When a spacecraft is in a gravitational well (like near a planet), it can gain additional speed by firing its engines while falling towards the planet. The gravitational pull accelerates the spacecraft, and when the engines are ignited at this high speed, the resulting increase in kinetic energy is greater than if the engines were fired at a slower speed. This principle makes the Oberth maneuver particularly useful for maximizing the efficiency of fuel usage during space missions.
Wikipedia
+1
Practical Applications
Powered Descents: During landings on celestial bodies, firing engines at high speeds allows for more effective deceleration and control.
1
Gravity-Assists: Spacecraft can use the gravitational pull of planets to gain speed. By timing engine burns during close approaches, they can maximize the Oberth effect and achieve significant velocity increases.
2
Multi-Stage Rockets: The Oberth effect is also crucial in multi-stage rocket designs, where upper stages can achieve greater kinetic energy than the total chemical energy of the propellants they carry.
1

3 Sources
Conclusion
The Oberth effect is a fundamental concept in astrodynamics that highlights the relationship between velocity and propulsion efficiency. By strategically planning engine burns at high speeds, spacecraft can optimize their energy expenditure, conserve fuel, and enhance mission capabilities, making it a vital principle in modern space exploration.
diversedaily.com
+1

Ending Pending

Last edited by Void (Today 11:36:05)

Void · Today 11:45:59

Most who are here know that I am no Rocketman. My ability to understand orbital mechanics are limited.

However, I have some other useful concepts down.

This post should be regarded as a continuation of the two previous posts. #203 and #204.

In 204 I suggest the possibility of a "Mars Oberth Starship" to assist a Starboat to return to Earth from Mars. As with cycling spaceships, however you face a great danger if your deep space acquisition between the Starboat and the "Mars Oberth Starship" fails.

In early days of Mars this danger might need to be faces.

But if the method is sensible, then what if you had 3 each "Mars Oberth Starship's" doing the Oberth burns, and 3 each Starboats?

your danger is perhaps considerably reduced. If you have one or two Starships that are successful, and any of the Starboats are successful, then you may have survivors.

That may sound dire, but if the Starboats are simply on their own, then they must execute their burns correctly or be in a dire situation anyway.

If one Starboat is off course, there is a chance that a "Mars Oberth Starship's" could have resources to alter course and intercept the "Lost" Starboat.

Anyway as is often true, there can be safety in numbers.

Ending Pending

Last edited by Void (Today 11:55:10)

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#201 2025-11-15 09:05:49

Re: Multi-Ship Expeditions, Starboat & Starship, Other.

#202 2025-11-15 10:31:02

Re: Multi-Ship Expeditions, Starboat & Starship, Other.

#203 Today 09:13:46

Re: Multi-Ship Expeditions, Starboat & Starship, Other.

#204 Today 11:14:53

Re: Multi-Ship Expeditions, Starboat & Starship, Other.

#205 Today 11:45:59

Re: Multi-Ship Expeditions, Starboat & Starship, Other.

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