McGregor LEO Fuel Depot

tahanson43206 · 2023-02-23 07:33:01

Update 2023/03/04 ... after spending quite a bit of time on and off line, GW Johnson appears to have found a solution that would allow a fuel station in LEO to be resupplied by Dr. John Hunter's gas gun. I am looking for a solution that does NOT require a circularization rocket in the payload. Dr. Johnson's work on space tugs may provide a solution. The idea is to use part of the payload mass to provide propellant for an on-station space tug to retrieve payload packages.

If the payload package is a ton, part of that mass would be allocated to retrieval of the next payload, so the net for sale to customers would be less by some amount. Dr. Johnson is still working the numbers, to see what fraction of the payload can be sold after deductions for orbit circularization.

*** original contents below:

In a somewhat surprising development, ChatGPT appears to have identified a location in GEO above the longitude of Texas as a suitable location for a fuel depot.

This topic is offered for development of this possibility. I would like to suggest a working title for this depot as the McGregor Fuel Depot in GEO in honor of the advanced technology developed in that city over a number of decades, and continuing to this day.

It is not coincidental that a resident of McGregor, Texas, has been a member of the NewMars forum since 2011.

ChatGPT proposed a modified Molniya orbit for delivery of payload to GEO from a ground based ballistic launcher. Such an orbit would allow the gravity of Earth to bend the flight path of a payload launched from Earth so that it arrives six hours (or so) later at the location of the fuel depot with almost zero relative velocity.

The cost of shipments (discounting payments for the launch hardware) would be the cost of electricity to charge the launch equipment.

While any material that can withstand the extreme conditions of ballistic launch might be shipped to McGregor Station, the first candidate material is water suitable for on-orbit electrolysis to make fuel for sale to customers. It is possible that such materials as kerosene (or similar hydrocarbons) could be delivered as well.

The calculations that led to the identification of the longitude of Texas in GEO as a potential site for a fuel depot are recorded/posted in the ChatGPT topic, on or near the date 2023/02/22.

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tahanson43206 · 2023-02-23 07:33:48

This second post is reserved for additional detail as it becomes available.

This post contains an image of the ground track of a proposed fuel depot in LEO.
http://newmars.com/forums/viewtopic.php … 87#p207187

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tahanson43206 · 2023-02-23 07:36:45

Here are a few snippets Google found about the City of McGregor, Texas

City of McGregor, TX
http://cityofmcgregor.com
Come explore the charm of McGregor, TX. Located in the growing Central Texas area, it is situated at the junction of Highway 84 and Highway 37 in McLennan ...
Contact Information
City Services
Employment Opportunities
City Forms
McGregor
City in Texas
McGregor is a city in McLennan and Coryell counties in the U.S. state of Texas. The population was 4,987 at the 2010 census. McGregor lies in two counties, as well as two metropolitan areas. Wikipedia
People also ask
What big city is McGregor TX near?
What is McGregor Texas known for?
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City of McGregor - Facebook
www.facebook.com › cityofmcgregortx
City of McGregor. 677 likes · 8 talking about this. Explore McGregor, Tx, and discover that charm is at the heart of the city.
McGregor, Texas - Wikipedia
en.wikipedia.org › wiki › McGregor,_Texas
McGregor is a city in McLennan and Coryell counties in the U.S. state of Texas. The population was 4,987 at the 2010 census.
Geography · Demographics · Economy
ZIP code: 76657
Counties: McLennan, Coryell
Area code: 254
Elevation: 692 ft (211 m)
Cities: McGregor - Texas State Directory Online
www.txdirectory.com › online › city › detail
General Information. Counties: McLennan. Population: 5,581. Primary Zip Code: 76657. Mailing: P.O. Box 192. Mc Gregor, TX 76657-0192 (254) 840-2806
City of McGregor - TML Directory - Texas Municipal League
directory.tml.org › profile › city
Member Type: Member City; Website: www.mcgregor-texas.com ... County: McLennan; Address: PO Box 192 McGregor, TX 76657-0192; Phone: (254) 840-2806 ...
City Planner: Bryan Anthony LeMeilleur
City Attorney: Charles Olson
City Councilmember, Ward 2: Paul Allison
City Councilmember, At Large: Sherry Adams
McGregor, Texas (TX 76561, 76657) profile - City-Data.com
www.city-data.com › city › McGregor-Texas
McGregor, Texas · Population in 2019: 5,331 (98% urban, 2% rural). · Estimated median household income in 2019: · March 2019 cost of living index in McGregor: ...
McGregor, TX 2023: Best Places to Visit - TripAdvisor
www.tripadvisor.com › United States › Texas (TX) › McGregor
McGregor Tourism: Tripadvisor has 591 reviews of McGregor Hotels, Attractions, and Restaurants making it your best McGregor resource.
Best Places to Live in McGregor, Texas
www.bestplaces.net › city › texas › mcgregor
Small city / college town - East-central Texas along I-35, 100 miles south of Dallas. State: Texas County: McLennan County Metro Area: Waco Metro Area City: ...

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SpaceNut · 2023-02-23 20:46:58

Texas does have few other locations for spaceports and what matter is infrastructure to support what you are launching from it.

https://www.faa.gov/space/spaceports_by_state

tahanson43206 · 2023-03-04 17:32:48

Dr. Johnson just wrote an email reporting progress in computing a possible orbit in LEO for a refueling station.

I've changed the topic title from GEO to LEO to reflect (a) the difficulty/impossibility of the GEO alternative, and the (relative) probability of success for a LEO versiion.

GW is still working the numbers, but I am (guardedly) hopeful they will resolve to a competitive solution to the refueling challenge.

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tahanson43206 · 2023-03-08 08:17:04

It appears that an orbit with an inclination of -35 degrees from the equatorial plane is a reasonable candidate for the On Orbit Refueling Depot system under discussion in this topic. Here is a screen shot of a display of ground tracks available online.

To see the proposed orbit, set inclination to -35 degrees and Altitude to 300 kilometers.

https://observablehq.com/@jake-low/sate … visualizer

Physics simulation stuff
G = 6.67191e-11
earthMass = 5.9721986e+24
earthRadius = 6371000
earthAngularVelocity = 0.0000729211840505999
satelliteVelocity = 7436.613621341653
satelliteAngularVelocity = 0.0010321462347455451
orbitRadiusInEarthRadii = 1.1309056663004238

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tahanson43206 · 2023-03-08 08:24:26

With reference to Post 6, it is apparent that the proposed refueling orbit is accessible to most major nations.

Resupply of the Depot can be achieved from many locations that are included in the orbital path.

In future years, when Solar System exploration is an activity of significance, resupply of space going vessels will require thousands of tons of propellant and other supplies on a regular basis, comparable to the flow of fuel and other supplies to keep the economies of Earth moving smoothly.

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tahanson43206 · 2023-04-26 09:54:50

This is a follow up to re-reading Spinlaunch topic from the top, as inspired by recent contributions by Calliban in another topic.

The quote below is from an article about Spinlaunch, that is itself quoted in the Spinlaunch topic.

Why SpinLaunch Did It
Should all go well, the A-33 mass accelerator will lead to an orbital launch facility with an arm that spins at 5,000 miles per hour (8,000 kilometers per hour). Once the full-scale system comes online, SpinLaunch engineers will target altitudes between 31 and 44 miles (50 and 70 km), at which point the launch vehicle’s propulsion stage will kick in to complete the journey to low Earth orbit. The finalized system should be able to launch satellites weighing 440 pounds (200 kilograms) to low Earth orbit.
Illustration: Vicky Leta
SpinLaunch says the system will result in a 10-fold reduction in launch costs and a 70% reduction in the use of fuel compared to chemical rockets. What’s more, the system should be able to perform around five launches each day. And that’s for a single accelerator.

Two hundred kilograms is the planned maximum delivery imagined for a full scale Spinlaunch system.

In discussion offline, GW Johnson and I considered a potential 1 ton payload delivered to LEO by one of John Hunter's larger gas launch systems.

For comparison, the gas launch system would use a 1 kilometer launch tube, plus whatever distance is needed to prepare the hydrogen gas for duty as an elastic propellant, working against the payload pod.

The proposed large scale spin launch machine would be 900 feet tall (diameter) which is only 274+ meters.

You get 200 kg to orbit (1/5th) for (about) 1/4th the distance.

The payload package in each case requires a solid fuel rocket to achieve orbital horizontal velocity.

However, if the payload packages are mounted in a ring around the perimeter of the spin launch rotor, then more than 1 ton of payload can be delivered to LEO in a single release.

What is more, the time required to reload a gas launch system is unknown, because Dr. Hunter's method for preparing the gas gun for a launch is proprietary. The spin launch system reload would include:

1) Time required to brake the system after payload release
2) Time required to inspect the system (very thoroughly)
3) Time required to load the new payload capsules (very carefully)

I'm going to estimate a potential elapsed time for reloading as an hour, and I'll estimate another hour to spin up the new load.

Since Dr. Johnson's proposed orbital refueling station would employ an orbital plane that crosses McGregor, Texas and passes midway between the Yucatan Peninsula and Cuba, any location on Earth which is covered by that plane would be able to launch fuel pods to LEO twice a day.

A single fling would (presumably) deliver a ton or more to LEO, and after achieving orbit the payloads could be picked up by automated tugs at leisure.

Since the need for a refueling depot is measured in thousands of tons of propellant for large scale missions (such as Large Ship to Mars) there would be a need for multiple spin launch facilities able to release payload shipments twice a day for as many days as the launchers remain serviceable between major teardown and rebuild.

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Mars_B4_Moon · 2023-09-25 16:14:04

U.S. Space Force and Astroscale to co-invest in a refueling satellite

https://twitter.com/SpaceNews_Inc/statu … 0109220240

tahanson43206 · 2023-12-11 11:38:07

https://www.yahoo.com/news/company-want … 33359.html

CNN
This company wants to create ‘gas stations in space’
Jacopo Prisco, CNN
Sun, December 10, 2023 at 7:04 PM EST·6 min read
2
Since the dawn of the space age — the launch of the Sputnik I in 1957 — humans have sent over 15,000 satellites into orbit. Just over half are still functioning; the rest, after running out of fuel and ending their serviceable life, have either burned up in the atmosphere or are still orbiting the planet as useless hunks of metal.
As such, they pose a threat to the International Space Station and to other satellites, with the European Space Agency estimating that over 640 “break-ups, explosions, collisions, or anomalous events resulting in fragmentation” have occurred to date.
That has created an aura of space junk around the planet, made up of 36,500 objects larger than 10 centimeters (3.94 inches) and a whopping 130 million fragments up to 1 centimeter (0.39 inches). Cleaning up this debris is costly and complicated, with several plans to do so but no tangible results yet.
One way to start tackling the problem would be to stop producing more junk — by refueling satellites rather than decommissioning them once they run out of power.
“Right now you can’t refuel a satellite on orbit,” says Daniel Faber, CEO of Orbit Fab. But his Colorado-based company wants to change that.
“When satellites run out of fuel, you can’t keep them in the right place in orbit and they become dangerous debris, floating around at very high velocities and risking collisions,” Faber explains. “But also, the lack of fuel creates a whole paradigm where people design their spacecraft missions around moving as little as possible.
“That means that we can’t have tow trucks in orbit to get rid of any debris that happens to be left. We can’t have repairs and maintenance, we can’t upgrade anything. We can’t inspect anything if it breaks. There are so many things we can’t do and we operate in a very constrained way. That’s the solution we’re trying to deliver.”
Space surgery
The concept of refueling and servicing satellites in orbit was pioneered by NASA in 2007, when — in collaboration with DARPA (the research arm of the US Department of Defense) and Boeing — it launched Orbital Express, a mission involving two purpose-built satellites that successfully docked and exchanged fuel. Later, NASA worked on the Robotic Refueling Mission (RRM), which further explored the challenges of refueling existing satellites.
Now the agency is working on OSAM-1, which was scheduled to launch in 2026 and will attempt to grab and refuel Landsat-7, an Earth-observation satellite that has run out of gas.
“This is a mission to refuel a satellite that wasn’t prepared to be refueled,” says Faber. “So they effectively have to do surgery on the satellite, cutting into it to get access to the fuel pipes. This allows for impressive satellite repair capability, but it comes at a price.” NASA said that OSAM-1 will cost about $2 billion in total.
Orbit Fab has no plans to address the existing fleet of satellites. Instead, it wants to focus on those that have yet to launch, and equip them with a standardized port — called RAFTI, for Rapid Attachable Fluid Transfer Interface — which would dramatically simplify the refueling operation, keeping the price tag down.
“What we’re looking at doing is creating a low-cost architecture,” says Faber. “There’s no commercially available fuel port for refueling a satellite in orbit yet. For all the big aspirations we have about a bustling space economy, really, what we’re working on is the gas cap — we are a gas cap company.”
A rendering of the future Orbit Fab Shuttle, which will deliver fuel to satellites in need directly on orbit. - Orbit Fab
Orbit Fab, which advertizes itself with the tagline “gas stations in space,” is working on a system that includes the fuel port, refueling shuttles — which would deliver the fuel to a satellite in need — and refueling tankers, or orbital gas stations, which the shuttles could pick up the fuel from. It has advertized a price of $20 million for on-orbit delivery of hydrazine, the most common satellite propellant.
In 2018, the company launched two testbeds to the International Space Station to test the interfaces, the pumps and the plumbing. In 2021 it launched Tanker-001 Tenzing, a fuel depot demonstrator that informed the design of the current hardware.
The next launch is now scheduled for 2024. “We are delivering fuel in geostationary orbit for a mission that is being undertaken by the Air Force Research Lab,” says Faber. “At the moment, they’re treating it as a demonstration, but it’s getting a lot of interest from across the US government, from people that realize the value of refueling.”
Orbit Fab’s first private customer will be Astroscale, a Japanese satellite servicing company that has developed the first satellite designed for refueling. Called LEXI, it will mount RAFTI ports and is currently scheduled to launch in 2026.
An original approach
According to Simone D’Amico, an associate professor of astronautics at Stanford University, who’s not affiliated with Orbit Fab, on-orbit servicing is one of the keys to ensuring a safe and sustainable development of space. “Could you imagine a ground mobility infrastructure, roads and cities, without gas stations and auto repair shops? Could you imagine single-use cars or airplanes?” he asks. “The development of space infrastructure and the proliferation of space assets is reaching a critical volume that is not sustainable anymore without a change of paradigm.”
D’Amico adds that there are many reasons why this hasn’t happened earlier, including, until recently, a lack of perceived need given the limited number of spacecraft, and the fact that on-orbit servicing technology has only now become economically viable due to progress in satellite miniaturization.
He believes that Orbit Fab is original, especially from a marketing perspective. “It’s probably the only company in the world that has positioned itself to deploy ‘gas stations’ in orbit,” he says. “I think Orbit Fab’s approach is really visionary and can pay off in the mid to long term. However, it has high risk in the short term, since satellites have to be designed having reusability and refueling in mind.”
Initially, Orbit Fab plans to find its market as a supplier of fuel to companies, such as Astroscale, that are planning to inspect, repair and upgrade satellites in orbit, or perform debris collection. According to Faber, succeeding in this sector could then convince the big telecom corporations, which operate a large number of satellites, to shake up their business model and embrace refueling and servicing.
He adds that once the pattern of sending and delivering fuel in orbit is established, the next step is to start making the fuel there. “In 10 or 15 years, we’d like to be building refineries in orbit,” he says, “processing material that is launched from the ground into a range of chemicals that people want to buy: air and water for commercial space stations, 3D printer feedstock minerals to grow plants. We want to be the industrial chemical supplier to the emerging commercial space industry.”
For more CNN news and newsletters create an account at CNN.com
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Calliban · 2023-12-11 16:49:08

I decided to model how much velocity a shell would need to posses, if launched from Earth's equator, to reach geostationary point with zero velocity. I integrated Newtons law of gravitation between R(earth) and R(GEO). This gives a required kinetic energy of 53.122MJ/kg, equating to a velocity of 10.3km/s. Atmospheric drag will increase the required muzzle velocity to about 11km/s.

Maybe a railgun could accelerate a shell to that velocity? I don't know what the barrel life would be. I cannot imagine that many people would want to live within fifty miles of a railgun launching shells into orbit. The noise pollution would be horrendous.

One way of reducing the required dV is to hang a collector from a satellite in GEO. That way we catch the shells before they reach GEO. Space junk would be a threat to the cable of course.

Last edited by Calliban (2023-12-11 16:59:28)

tahanson43206 · 2023-12-11 18:39:19

For Calliban re #11

Thank you for introducing the kinetic launch concept to this topic! Your calculations for the shell to reach GEO look reasonable to me, without doing any calculations. Others have performed that calculation, and your results look (in the ballpark) compared to what I remember from those earlier estimates.

One calculation I did not see in Post #11 is giving your shell the horizontal velocity it needs to stay in GEO.

When the shell is fired, it will have a bit of horizontal momentum, depending on where it is with respect to the equator, where the velocity is greatest. The shell will need a horizontal velocity of (about) 7000 miles per hour ...

Per Google:

The aptly titled geosynchronous orbit is described in detail: “At an altitude of 124 miles (200 kilometers), the required orbital velocity is just over 17,000 mph (about 27,400 kph). To maintain an orbit that is 22,223 miles (35,786 km) above Earth, the satellite must orbit at a speed of about 7,000 mph (11,300 kph).

The need for horizontal velocity is why all current designs for kinetic launchers include a solid fuel rocket as part of the package.

You can find the horizontal rocket in the work of Dr. John Hunter, which is documented at some length in the forum archives.

***
Since it is possible you have missed Dr. Johnson's work on this specific issue, I'll just summarize that he found that the flight plan that allows for the least costly horizontal thrust is achieved by doing two burns ... One is at the apogee of a very high ellipse, and the other is at the intersection of the perigee with the space station in LEO you might be trying to reach. The combination is less costly than a single horizontal burn if the shell can only reach LEO.

The work is documented in the forum, and links are provided to the papers and slide shows.

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#1 2023-02-23 07:33:01

McGregor LEO Fuel Depot

#2 2023-02-23 07:33:48

Re: McGregor LEO Fuel Depot

#3 2023-02-23 07:36:45

Re: McGregor LEO Fuel Depot

#4 2023-02-23 20:46:58

Re: McGregor LEO Fuel Depot

#5 2023-03-04 17:32:48

Re: McGregor LEO Fuel Depot

#6 2023-03-08 08:17:04

Re: McGregor LEO Fuel Depot

#7 2023-03-08 08:24:26

Re: McGregor LEO Fuel Depot

#8 2023-04-26 09:54:50

Re: McGregor LEO Fuel Depot

#9 2023-09-25 16:14:04

Re: McGregor LEO Fuel Depot

#10 2023-12-11 11:38:07

Re: McGregor LEO Fuel Depot

#11 2023-12-11 16:49:08

Re: McGregor LEO Fuel Depot

#12 2023-12-11 18:39:19

Re: McGregor LEO Fuel Depot

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