electromagnetic launch with microwave propulsion

SpaceNut · 2020-03-19 18:28:38

The drum disk alternators sound like flywheel generators.
https://clean-greenenergy.com/flywheel- … generator/
https://www.homemade-circuits.com/free- … ywheel_10/
https://www.irjet.net/archives/V5/i1/IRJET-V5I1226.pdf
https://www.globalspec.com/learnmore/el … er_systems

edit
a while ago we were talking about the thermal protection of moving through the thick atmosphere and its here on GW's Blog...
http://exrocketman.blogspot.com/2020/01 … -heat.html
I am sure the many post that are there will be of interest....

tahanson43206 · 2020-03-20 04:46:11

For SpaceNut .... thanks for the links for rotating energy storage systems, AND for the link to GW Johnson's blog on heat in various flight regimes.

For GW Johnson ... thank you for that very nice overview of the subject. I was glad to see the positive comment from January 30, 2020.

I appreciated (in particular) your coverage of the difference that occurs when gases become ionized, and depart from ideal gas law behavior.

One of the options available for study in this topic is flight from the surface of the Earth at velocities attainable by electromagnet acceleration systems.

I get the impression that a vehicle may enter the ionization regime immediately, although what should be concluded from that is not yet clear to me.

I am interested in finding a solution to sonic disturbance caused by flight of an object in the upper ranges of possibility, and note that production of sonic energy and production of thermal energy occur at the same time. I'm assuming for the moment they are not directly related, but suppose they may be.

Edit#1: I have updated Post #2 of this topic to show a quick summary of status as I understand it at this point.

(th)

Last edited by tahanson43206 (2020-03-20 05:36:34)

SpaceNut · 2020-03-20 10:33:37

Seems the rocket equation must be worked to find mass that can be removed so that the eml or catapult systen can be worked as we are not going to keep putting in the energy rise for the ramp as a result of mass that needs to be moved.

https://en.wikipedia.org/wiki/Tsiolkovs … t_equation

https://www.planetary.org/blogs/guest-b … art-2.html

While thats the total equation for rocket launching we are more into the equation of use for each stage of the rocket as we are trying to remove any or portions of that mass.

https://en.wikipedia.org/wiki/Multistage_rocket

https://en.wikipedia.org/wiki/Single-stage-to-orbit
https://en.wikipedia.org/wiki/Two-stage-to-orbit
https://en.wikipedia.org/wiki/Three-stage-to-orbit

http://www.rocketmime.com/rockets/multistg.html
Handy Excel Spreadsheet for 3-stage calculation

http://www.rocketmime.com/rockets/rckt_eqn.html

https://ocw.mit.edu/courses/aeronautics … _Lec14.pdf
https://spacecraft.ssl.umd.edu/academic … t_perf.pdf

Well I am ok with Algebra and Physics but not so much with Calculus, but here is a calculator or 2 for use

http://quantumg.net/rocketeq.html
https://calculator.academy/rocket-equation-calculator/
https://www.omnicalculator.com/physics/ … t-equation

SpaceNut · 2020-03-20 11:45:04

We are working with momentum from the initial launch and for each stage drop off and ignition firing as well.
http://www.philsrockets.org.uk/rocket%20equation.pdf

While still working towards the given payload for the design.
https://www.reddit.com/r/RealSolarSyste … _to_orbit/

https://www.reddit.com/r/KerbalSpacePro … lculation/

tahanson43206 · 2020-03-20 13:57:03

For SpaceNut re topic ...

First, thanks for your interesting and helpful additions to the topic. They would hit the spot if we could (somehow) attract some of the thousands of college students (and their professors) who are twiddling their thumbs right now!

I would ** really ** like to see an analysis of the physics for a telephone pole shaped cargo vehicle that would contain a solid fuel finishing rocket, and which would launch from an EML at an angle as discussed earlier in a post in this topic, for the West side of Puerto Rico.

This ** kind ** of analysis has been done before by many individuals and organizations, but here is an opportunity for new members of the community to give it a try.

I'll offer some (arbitrary) figures to help, because otherwise there are too many variables:

1) Payload cargo to be delivered to LEO: 1 Metric ton
2) Mass of vehicle not including fuel in finishing rocket: 1 Metric ton
3) Mass of fuel to be expended for topping off the ellipse after launch, to match the customer site velocity

The challenge, should someone accept it, is to figure out what velocity must be imparted to the telephone pole vehicle at the surface of the Earth, to achieve a successful docking with the customer facility.

For a working size for computing drag, let the diameter of the telephone pole vehicle be 30 centimeters.

(th)

tahanson43206 · 2020-03-20 13:59:03

For SpaceNut re topic ...

Today I had a chance to catch up with the relative I know, who is married to a professor of aerospace engineering at a local school. The relative informed me that in the age of work-from-home, the professor had a set of 78 Skype images on his screen for a recent seminar.

That is ** way ** more than I have ever experienced << grin >>

(th)

SpaceNut · 2020-03-20 17:18:22

Sure the shape of the payload nose diameter will be part of the atmospheric air drag on momentum once free of the launcheml units ramp.
Effect of atmospheric drag on rocket launches and benefits of high altitude launch sites

Amospheric drag

Hurling Satellites Into Space Seems Crazy—but Might Just Work A startup called SpinLaunch wants to do away with costly launch rockets. Let's look at the physics.

https://www.nextbigfuture.com/2018/02/s … aunch.html

Spinning to get the item to orbit is interesting...image matches what you have envisioned

The pegasus is an air launch
https://www.colorado.edu/faculty/kantha … t_muir.pdf

contains velocity, altitude and duration time for a delta rocket launch path which gives aid to numbers for what we want to do.

Pegasus II to place up to 6,100 kg with a 5 m fairing into LEO such that our target payload should fit the 1 m diameter....

Sounds like you found an in for looking at what we are doing.

tahanson43206 · 2020-03-20 17:33:59

For SpaceNut re #107

Thank you for another nifty set of links! I followed the Spinner link and found the article (as you suggest) appropriate for those who may be thinking about the telephone pole freight vehicle.

Rhett Allain is an associate professor of physics at Southeastern Louisiana University. He enjoys teaching and talking about physics. Sometimes he takes things apart and can't put them back together.

Interesting, right off the bat, is that the spin concept appears to launch at a velocity close to the Mach 5 - 6 range that kbd512 proposed.

Beyond that, I was intrigued that Professor Allain convinced himself the spinner could work, after approaching the problem with considerable skepticism.

(th)

tahanson43206 · 2020-03-20 20:31:03

For SpaceNut re #107 (continued) ...

I followed the NextBigFuture link and found this:

The Air force and Launchpoint are working on magnetic sled launch systems.
Before 2006, there was a $500,000 Phase II contract awarded from the U.S. Department of Defense Small Business Technology Transfer Program, LaunchPoint engineers, under the direction of Jim Fiske, evaluated an innovative magnetically-levitated space launch system.
The Launch Ring, as it is called, would accelerate a small payload within a subsurface magnetic tube until it reached escape velocity. At that point, the payload capsule would exit the ring onto an elevated ramp and be launched into orbit. The results of LaunchPoint’s R&D analyses suggest that a space launch system utilizing maglev technology could work very well, creating a more cost-effective means of launching small payloads into space.

One of the interesting aspects of the proposal quoted above is the idea of accelerating the object to be launched in a ring, instead of in a straight line, as I have been imagining was kbd512's concept, based upon the aircraft carrier catapult model. I like the fact these folks were thinking of building up velocity to escape velocity, which ** should ** be sufficient to overcome drag in the early going, and still have enough momentum to allow the finishing rocket to match orbit with the customer facility.

Humans have a lot of experience accelerating matter in circles until high velocities are achieved. However, that experience is limited to masses on the order of atoms or small ions at most. The mass these folks talking about is in the range of 100's of kilograms.

I have difficulty imagining an engineering team successfully developing a release mechanism for either the Launch Ring or the Spinner. An error in timing of nanoseconds would deliver lots of kinetic energy to the inside of the acceleration chamber.

For that reason, I prefer kbd512's (comparatively) simple linear accelerator, although I expect the electrical engineering required to be world class. As mentioned in an earlier post in this topic, the problem of drag on a vehicle accelerating in a linear launch tube could be alleviated by using a hybrid of electromagnetic and gas acceleration methods.

To simplify things further, and to reduce cost considerably, the gas acceleration could be accomplished by using air. The gas would only be effective up to the speed of sound in air (Mach 1) but giving the freight vehicle a friendly push during the early stage of acceleration would help the electromagnetic component to carry out its more strenuous duty, to reach escape velocity, if that is actually possible.

(th)

tahanson43206 · 2020-03-20 20:56:29

For SpaceNut re #107 links ...

Both the Spinner concept and the Launch Ring anticipate reducing drag by evacuating the acceleration chamber.

I wondered how the Hyperloop train concept dealt with air resistance inside the tubes they'll be using, so asked Mr. Google:

The basic idea of Hyperloop as envisioned by Musk is that the passenger pods or capsules travel through a tube, either above or below ground. To reduce friction, most -- but not all -- of the air is removed from the tubes by pumps. Overcoming air resistance is one of the biggest uses of energy in high speed travel.Aug 16, 2019

In thinking about the presence of air ahead of a vehicle being accelerated by an electromagnetic linear motor concept, it seems potentially feasible to deliver a volume of air travelling up the tube, in a smaller pipe adjacent to the EML. If a suction device were fitted at the top of the tube, and if holes are cut in the smaller pipe to admit air from in front of the accelerating vehicle, then the effect of drag on the vehicle could be reduced.

A designer (or more likely a team of designers) would need to try to find the optimum amount of suction that might be applied, taking into account the energy needed to operate the equipment. It might turn out to be more efficient to simple allow plenty of room in the EML tunnel to permit ambient air to move to the side as the vehicle approaches. There would be a sound produced at the mouth of the tunnel as air inside the tunnel reverberates after the vehicle has departed.

The effect might be a very low frequency organ pipe sound.

(th)

Last edited by tahanson43206 (2020-03-20 20:57:24)

tahanson43206 · 2020-03-21 07:02:02

For SpaceNut and all ...

I have edited Post #2 of this topic to include a new technical option:

Technology option 3: (Edit:2020/03/21) Same as #1, but accelerate to near escape velocity.

In making this decision, I am inspired by SpaceNut's discovery and presentation of the two "sling" concepts under discussion/development.

Taking kbd512's original idea as a starting point, I am now thinking about a linear launch facility able to deliver a three metric ton telephone pole vehicle to near escape velocity at the surface of the Earth. An added fillip is the use of the ocean trench West of Puerto Rico to permit launching at an angle.

Interested readers of this forum will find kbd512's introduction of Puerto Rico earlier in this topic.

Dr. John Hunter had planned to suspend a 1 kilometer long hydrogen accelerator in the ocean, with the ability to maneuver to change the angle of launch, and the azimuth of launch, to meet customer requirements.

I am proposing to fix the launcher in azimuth and in angle of altitude, and to vary the velocity of the cargo vehicle depending upon the customer requirements.

This policy will provide a fixed orbital plane that potential customers can utilize for restocking supplies of fuel, oxidizer, water, hard goods and anything else capable of withstanding high G force at the initial launch. The customer facilities can be spaced out horizontally and vertically in the chosen orbital plane.

The cargo vessel (in this scenario) will include a fixed strength orbital rounding rocket, and the apogee of the ellipse of the vehicle flight path will be determined by the impulse given to the vehicle by the EML.

In this scenario, Puerto Rico would serve as the base station for Earth based operations, and would supply power and launch preparation services for all customers.

Call for Volunteers:

In this time of increased available time, for students, professors and professionals, there is an opportunity for everyone with the interest/motivation to dive into solving the myriad challenges that present themselves.

In order to drastically reduce the uncertainty caused by endless discussion of alternatives, I am offering a fixed set of specifications for the EML and attendant facilities:

1) Cargo Vehicle is designed in the form of a telephone pole, 30 centimeters in diameter.
2) Total mass of the vehicle is 3 Metric tons, with payload delivered to the customer no less than 1 Metric ton
3) The vehicle must be designed to serve as a component of a large scale on-orbit construction project, after payload, fuel and electronics are removed.
4) The navigation and control systems will reside in the tip behind a refurbishable heat shield and sonic boom attenuator.

Edit#1: To reduce ambiguity further,

The entire system (launcher and vehicle) should be able to deliver cargo in the range from just barely in orbit to Earth escape.

The reason for the "just barely in orbit" floor is the potential to rescue stranded space travelers or valuable equipment who might be just skimming the top of the atmosphere. The ability to fine tune acceleration is a feature of EML, according to reports about the US Navy implementation (see kbd512 posts in topic).

SearchTerm:EMLSpecs
SearchTerm:EMLSpecifications
SearchTerm:PuertoRico

(th)

Last edited by tahanson43206 (2020-03-22 07:21:25)

SpaceNut · 2020-03-21 10:20:33

The vaccumn like in the hypertunnel and the spinway units only reduce the speed of motion while its present but for a rocket the trip through the atmosphere is just a drag that must be accounted for just like gravity on the mass of the rocket. The energy imparted to get the delta of speed we want after the travel through the air to altitude before we fire up the staged rockets engines are something we will need to live with and account for to make this work.
So far from everything we have this is something to positively build for the moon and quite possibly on mars once we have a solid base to work from.

The rockets engine to be able for course correction on launch is call gimbal and really are a liquid engine use. Not sure how much of that could be done with solid fuels.

This company's rocket seems to be close to discription Rocket Lab's Electron Rocket

tahanson43206 · 2020-03-21 10:43:00

For SpaceNut re #112

Thank you for pointing out a separate need (course correction) above and beyond orbit circularization, which is required to cause the cargo vehicle to achieve a sustained orbit after boosting to the desired altitude. All vehicles driven by an impulse from the surface (to the best of my knowledge) will require this orbit circularization rocket, with the notable exception of those which are given sufficient velocity at launch to escape the gravitational field of the Earth entirely.

However, your point about the need for fine tuning the course of a vehicle which is intended to dock with a customer facility is an important one. I ran a quick check of Google for reports on methods to steer solid fuel rockets, and found a substantial number.

The designers of the telephone pole cargo vehicle have two metric tons (given an arbitrarily chosen total of 3 Metric tons) to use for all needed purposes.

As reported in an earlier post, the impulse given to a particular vehicle for a particular customer can be varied to best match the orbit of the customer facility, but it seems clear that some course correction capability is needed.

There would be no gimbal operation on the solid fuel rocket that is used for orbit circularization, as you point out.

Werner Von Braun used plates/vanes in the exhaust of the V2 to steer the vehicle. With a bit of luck, it may be possible to design this vehicle to achieve matching orbits with customer facilities without this refinement. However, it is available as a fallback.

One technique for vehicle navigation accuracy that is honored in the mists of time is rotation of the vehicle. This is particularly applicable to a long object such as the telephone pole cargo vehicle.

From Google:

Search Results
Web results
Big Bullets for Beginners - FAS.orgfas.org › man › dod-101 › sys › land › bullets2
Feb 6, 2000 - SPIN-STABILIZED PROJECTILES Most guns in use today use spin-stabilized projectiles. Spinning a projectile promotes flight stability. Spinning is obtained by firing the projectiles through a rifled tube. The projectile engages the rifling by means of a rotating band normally made of copper.

(th)

Last edited by tahanson43206 (2020-03-21 10:43:55)

SpaceNut · 2020-03-21 12:50:08

Here is the RocketLab Launcher which looks ideal to pick for the eml launcher aid as its fits the static capabilities.
Electron (rocket)
Size
Height 17 m (56 ft)
Diameter 1.2 m (3 ft 11 in)
Mass 12,500 kg (27,600 lb)
Stages 2–3

https://en.wikipedia.org/wiki/Electron_(rocket)

Payload to 500 km Sun Sychronous Orbit 150–225 kg (330–495 lb)

That means for a LEO of 400 km we can be expected to launch near all of what we want with the current rocket for mass and still have all the features for the expendable rocket but with a higher payload with the EML system.

payload fairing or shroud is on page 8 and indicates 2.5 m tall with the body diameter of 1.2 m wide.
https://web.archive.org/web/20171130054 … -Guide.pdf

Things to make the first stage reuseable are landing legs, computer control, engine to be re-igniteable, 1/4 more for fuels for the stage that is being return which will add to the overall mass, parachutes for upper atmosphere to landing thrusters possibly to reduce fuels, and grid fins to stabilize if during the landing..

kbd512 · 2020-03-21 23:36:28

SpaceNut,

I really liked that article from Professor Rhett Allain. For once we have a news article written by someone who has the expertise to put some mathematics behind a new concept, rather than parroting back poorly-understood and partially explained ideas as nearly all normal media sources do. That part blew my mind. Why can't we have more people like him explaining new ideas and current events?

The homework question regarding the spin rate required to provide sufficient velocity to remain in LEO without using a rocket boost was somewhat oddly-worded, though. As GW can no doubt explain to us, there's not really such a thing as "orbital velocity". A vehicle can achieve the velocity required to orbit the Earth at some specified altitude from the surface of the planet, but the only actual possibilities for purely "launched" projectiles of any kind are a ballistic arc back into the surface of the planet that the projectile was launched from or achieving escape velocity. I guess what Professor Allain actually meant was, "What spin rate would be required to achieve the velocity necessary to orbit the Earth at such and such altitude, using a rocket burn only to circularize the orbit?"

I also liked Professor Allain's article on geothermal energy, just in case anyone here did some extra perusing of his work for Wired. How it is that he doesn't also equate geothermal energy with energy ultimately sourced from stars is anyone's guess, but nonetheless it shows that we have plenty of juice to tap, just from the Earth itself, until long after the Sun becomes a red giant and transforms Earth into a glowing lifeless ember.

tahanson43206 · 2020-03-22 05:51:11

For SpaceNut ....

In the past few days, I ** thought ** I saw a post from you referencing the "Scout" launcher, but I couldn't find it today. This topic is about electromagnetic launch, but I ** think ** your post was about possible application of the orbital stage for the EML application.

In any case, because GW Johnson has mentioned "Scout" on numerous occasions, I ran a search of the forum archive, and found 25 references;

From 2019-12-21
http://newmars.com/forums/search.php?se … =854180262

From 2019-09-15
http://newmars.com/forums/viewtopic.php … 84#p159984

Many others (22 to be exact)

First from 2011-12-08
http://newmars.com/forums/viewtopic.php … 73#p110473

So! If GW Johnson happens to spot this post, and would be willing to comment ...

Could the "Scout" 4th stage handle orbit circularization for an EML launch?

It would have to be packaged differently, to survive the rigors of passage through the lower atmosphere.

What I am imagining is that the stage contains navigation hardware and control software, and thrusters sufficient to dock with a customer facility.

(th)

tahanson43206 · 2020-03-22 05:54:29

For SpaceNut re #114

Thank you for including RocketLab in this topic. While the vehicle itself is traditional in every sense, the engineers who designed and built it may be interested in the challenge of circularizing orbit and docking with a customer facility after an EML launch.

(th)

tahanson43206 · 2020-03-22 06:24:19

For kbd512 re Post#5

I took the time to go back and re-read Post #5 more slowly. The option of working with college students is interesting.

We are at a time (spring of 2020) when there are lots of college students who are interested in space and specifically aerospace engineering, who have a bit more time on their hands than usual.

If any of those folks happen upon this topic, and might have an interest in participating, please go back to the top of the topic and read it through.

Post #5 provides a framework which might be a starting point.

I am trying to provide a set of specifications for a cargo vehicle in order to drastically reduce uncertainty caused by the new options that are being added to this topic every day (or so).

Please see Post #111 of this topic for those specifications.

To find the post using the forum search feature, enter: S e a r c h T e r m : and :E M L s p e c s
Select Author tahanson43206

Remove spaces from the search arguments. They are added here to avoid unwanted discovery by the search feature.

(th)

Last edited by tahanson43206 (2020-03-22 06:25:21)

SpaceNut · 2020-03-22 10:03:44

for post 116
http://www.astronautix.com/s/scout.html
https://en.wikipedia.org/wiki/Scout_(rocket_family)

These are a family of solid fueled rockets simular to the others which have been meantioned in the topic thus far.
Capable of being used once a sled style launcher for the eml system is created to propel the rocket up the ramp towards space.

tahanson43206 · 2020-03-23 06:19:18

For SpaceNut re Scout in particular and topic in general ...

Thank you for continuing to look for pertinent technology ideas that apply directly to the EML initiative by kbd512, or indirectly.

In-as-much as GW Johnson had direct experience with the scout, I am hoping it is not too much of an imposition to assist with design of the solid fuel rocket for orbit circularization for the vehicle proposed in the subtopic I am offering here. I am looking for posts that answer specific questions applicable to the specific design given at the locations cited below.

1) Design of vehicle body to complete launch and docking and cargo delivery, and then merge seamlessly into a large scale on-orbit construction project, such as building a full size Aldrin Cycler, or a full size Von Braun space station.
2) Design of solid rocket component. kbd512 has proposed use of a modern hybrid solid, similar to the AMROC but with different fuel
3) Design of navigation and docking electronics and related subsystems

tahanson43206 wrote:

For kbd512 re Post#5
I took the time to go back and re-read Post #5 more slowly. The option of working with college students is interesting.
We are at a time (spring of 2020) when there are lots of college students who are interested in space and specifically aerospace engineering, who have a bit more time on their hands than usual.
If any of those folks happen upon this topic, and might have an interest in participating, please go back to the top of the topic and read it through.
Post #5 provides a framework which might be a starting point.
I am trying to provide a set of specifications for a cargo vehicle in order to drastically reduce uncertainty caused by the new options that are being added to this topic every day (or so).
Please see Post #111 of this topic for those specifications.
To find the post using the forum search feature, enter: S e a r c h T e r m : and :E M L s p e c s
Select Author tahanson43206
Remove spaces from the search arguments. They are added here to avoid unwanted discovery by the search feature.
(th)

AMROC developed the largest hybrid rockets ever created in the late 1980s and early 1990s. The first version of their engine, fired at the Air Force Phillips Laboratory, produced 312,000 newtons (70,000 lbf) of thrust for 70 seconds with a propellant combination of LOX and hydroxyl-terminated polybutadiene (HTPB).
Hybrid-propellant rocket - Wikipedia

Edit#1: I found this paper from 2010 reporting "Recent Advances in Hybrid propulsion"
https://web.stanford.edu/~cantwell/Rece … 6_2010.pdf

(th)

Last edited by tahanson43206 (2020-03-23 06:38:45)

kbd512 · 2020-03-23 09:52:19

tahanson43206,

The suggestion of using a hybrid solid was for a vehicle that was launched from a more conventional track with much lower acceleration rates. It would make more sense in this application to use a liquid monopropellant like HAN because the grain of the paraffin wax based solid motor I had in mind would be destroyed by the acceleration forces involved. A very simple liquid monopropellant boost / orbital circularization engine would require far less propellant and the reduced specific impulse performance would not be a significant detriment.

Beyond that, your supposition of why I want this lower cost system implemented is spot on. I want to create true interplanetary transports that can carry as many people as an aircraft carrier and to refuel them using a much lower cost method of shipping small quantities of bulk propellants and metals to an orbital depot, but in the indefinitely storable form of H2O and LCO2. A solar array would provide the power required to transform water and Carbon Dioxide into LOX/LCH4 or LOX/LH2 just prior to departure. The surface transports would still be Starship Super Heavies configured for passengers or cargo. The passenger models would deliver 1,000 colonists to orbit or to the surface of Mars per flight. The Starships would still see plenty of service for delivery of delicate components for these truly massive interplanetary transports in the form of rocket engines / electronics / batteries / solar panels / food / people, but low cost bulk commodities would need to be delivered as cheaply as possible, which means conventional rockets are out of the question. Low value bulk commodities would include propellants and fabrication / construction materials like Aluminum or steel for gigantic propellant tanks or anything other structure too massive to easily ship via Starship Super Heavy. Another example would be spools of CNT fiber to be woven into cloth / fabric, serving as the restraint layers for inflatable habitat modules. Other examples of the consumable variety would include nearly raw foodstuffs like flour or baking soda and sanitization supplies such as liquid laundry detergent and bleach or washcloths / towels / clothing. Use your imagination. There's lots of stuff that needs dirt cheap launch.

When the Navy takes food onto an aircraft carrier, it comes in bulk containers to minimize the still-substantial packaging waste. We're going to do the same thing here, except we'll need to eliminate even more of the packaging waste. Anything that can be transported as a powder or liquid will be pumped. Towels might be individually sized for men, women, or children, for example, and what gets shipped to the ITV is simply continuous bolts of fabric, or perhaps turned into fabric, that are then cut and sewn to final dimensions by a seamstress robot. Apart from the space suit a colonist is wearing to keep them alive if Starship loses pressurization, we might ship people to the ITV naked and make the clothing on the ship, the moment they set foot on the ship, to minimize the cost of the materials / packaging and to ensure that the clothing is custom designed for the wearer to ensure it fits perfectly and nothing is wasted due to the incredible cost of shipping anything into space. There won't be any "baggage" as a function of cost. We're going to deliver your body and whatever is needed to keep you alive, perhaps 1 electronic device for entertainment per person like an iPhone or iPad, and nothing else. The colonists will be walk-on members of the ship's crew, responsible for cleaning the ship, servicing it as required, and feeding each other, as is the case for anyone serving aboard US Navy ships. It's like being aboard a cruise liner, except you make your own meals and wash your own clothes and fix your own ship. Apart from the fact that Mother Nature will be taking over the duties normally assigned to the enemy, primarily trying to kill you, that's the best way to describe being in the Navy.

You'll get to see the world, or at least half of it at any given time, and wave goodbye to it as you journey to another world. It'll be fun. I make no guarantees about what the next world will be like, though. Honesty in advertisement and all that jazz, though in light of what we're planning on building maybe the entertainment should be heavy metal themed.

SpaceNut · 2020-03-23 10:51:47

tahanson43206 the trade off for the hybird at the time did not have a composite tank for use with the Lox which would save on mass for the launcher as compared to the same mass GEM solids with same thrust. The hybird does add to the complexity to have the Lox
with solid as it's burning while you can turn off the lox does not stop the solid from burning totally for a period of time and once a solid only rocket is lit it can not be turned off and that is why we favor liquids.

tahanson43206 · 2020-03-23 11:10:29

For kbd512 re #121 ... as so often happens with your longer posts, I need time to study it.

For SpaceNut re #122 ... for the sake of the high school students who (I hope) will be visiting this forum to learn, please take a look at #122 ..

The wording is (possibly) a bit confusing ... there are three types of chemical rockets (that I know of) ... there are solid fuel rockets, there are liquid fuel rockets, and there are hybrid rockets. The ** whole ** point of designing a hybrid rocket is to able to TURN OFF the burn.

You may be able to find online references to the history of the hybrid rocket. I found a reference to AMROC but there must be many others. An entire company was established to build and fly hybrid rockets because (it was believed) they would be safer than traditional solid fuel rockets or liquid rockets.

(th)

SpaceNut · 2020-03-23 15:05:03

The troubles of the solid rocket is one that if started can not be stopped already indicated, joint seal failures and one where the ignitor fails to lite the rocket. Of course some of these conditions can be had for all rockets in general.

tahanson43206 · 2020-03-23 21:53:36

For kbd512 re #121

The suggestion of using a hybrid solid was for a vehicle that was launched from a more conventional track with much lower acceleration rates. It would make more sense in this application to use a liquid monopropellant like HAN because the grain of the paraffin wax based solid motor I had in mind would be destroyed by the acceleration forces involved. A very simple liquid monopropellant boost / orbital circularization engine would require far less propellant and the reduced specific impulse performance would not be a significant detriment.

A Google search for the monopropellant HAN came back with 25,100 results. The citations start at 1996 and continue right up through mid-2019.

www.sciencedirect.com offers an article which appears to show that HAN is superior to hydrazine, which is encouraging.

I'm planning to spend some time tomorrow looking at some of the citations. A key concern is how this material would handle the rigors of a high-G launch, but the fact you've suggested it at all tells me it may be suitable. This material could be used for docking as well as circularization, which would simplify design, manufacture and operation of these vehicles.

I had been assuming that Dr. Hunter was planning to use traditional solid rocket fuel for the circularization burn, but that is just a guess, and besides, he may not have spent much time on that detail, compared to the challenge of designing a kilometer long gas gun.

Speaking of gas guns for a moment ... One of the reasons I'm interested in supporting your initiative here (to the extent I can), is my concern about wear of the barrel of the gas launcher as each sabot slides along the stretch with ultra-high-pressure hydrogen gas trying to escape past the seal.

The electromagnetic launcher would presumably NOT subject either the sled or the fixed track to physical contact, thanks to magnetic repulsion due to induced magnetic fields.

New subtopic: Maintenance of a linear motor

Google came up with documents on maintenance of linear accelerators used for medical treatment. One stored at the National institute of Health web site contains analysis of failure modes and possible ways of predicting failure in order to schedule preventive maintenance.

While I do not know (at this point) what the failure mode of a linear motor on the scale we are discussing here may be, I am confident there is at least one, and there are probably several. in particular, since the rotating storage devices are mechanical systems subjected to enormous forces during operation, failure is to be anticipated and therefore should be planned for. Coils subjected repeatedly to powerful electric currents and the magnetic forces generated in operation of the system are surely subject to failure if allowed to overheat, for example.

(th)

Last edited by tahanson43206 (2020-03-23 22:16:55)

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#101 2020-03-19 18:28:38

Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

#120 2020-03-23 06:19:18

Re: electromagnetic launch with microwave propulsion

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Re: electromagnetic launch with microwave propulsion

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