electromagnetic launch with microwave propulsion

tahanson43206 · 2020-04-07 17:29:15

Edit#1 ... thank you for the links in Post #174 ...

I found the mass (estimated) I was looking for!

The only EML that is working today for launching vehicles is the US Navy EML installed on the carrier Gerald R. Ford.

That EML was designed to launch fighter aircraft on the high side, and it has the capability to launch lighter aircraft such as drones on the low side.

An EML that would be designed for a space vehicle would be designed to accelerate a much greater mass than is required of the US Navy EML.

In addition, taking kbd512's vision as a guide, it would be designed to accelerate that much greater mass at a level far greater than the 2.5 G's estimated to be developed by the Navy EML. kbd512 has called for an acceleration capability of 10 G's.

The (estimated) mass of the Falcon 2nd stage (in one of the configurations reported in one of the links you provided) is ~78.1 metric tons.

kbd512 has most recently discussed the possibility of designing an EML and rocket combination that would deliver 1 metric ton to LEO.

Meanwhile, I am pursuing the pathway laid out in the NASA paper (from 2009) as shown in Post #5 of this topic, by kbd512.

In both cases, the EML that would be needed would far exceed the performance of the US Navy system. What is important about the US Navy system is that it is working, so that the technology it embodies can be imagined capable of extension to the much greater requirements of a space launch system.

in that sense, it would be correct to say that no EML of the required capability exists on Earth today (to the best of my knowledge).

I think it is possible a more capable EML can be designed, and it is even remotely possible one can be built.

Whether such an EML can actually perform as intended is an open question.

(th)

Last edited by tahanson43206 (2020-04-07 19:07:36)

SpaceNut · 2020-04-08 23:42:41

I made a meantion of the Rocketlab rocket for its size as its within the typical payload to orbit that we can work with.
Rocket Lab tests Electron stage recovery

Lots of good data in the article.

elderflower · 2020-04-09 03:30:58

Any EML that I can imagine will be limited by the nature of its payload. The extreme accelerations proposed would risk quite a bit of damage with sensitive equipment or humans. Also the driver must not be heated so much that it sticks or even melts in the track and additional track must be allowed to decelerate the driver after release of the payload and before it hits the buffers unless you are going to discard it with every launch.
I think we need to develop EMLs for launching payloads from low escape velocity bodies which will not have atmospheres.

tahanson43206 · 2020-04-09 07:22:03

For elderflower re #178

It is good to see your contribution to the topic.

Every statement in your post reinforces something said earlier in the topic, which is encouraging because it implies the earlier comments would have your approval.

kbd512 is the manager of this topic. I am participating because I think the topic is worth supporting, and because I hope it will lead to concrete proposals able to withstand withering scrutiny by potential funders.

Your point about overheating the drive plate is particularly interesting to me. The ONLY working example of an EML able to launch substantial mass (ie, a fighter aircraft), is limited to a run of a short distance and a launch velocity of about 150 miles per hour.

kbd512 has proposed increasing G force from the demonstrated 2.5 to 10. That goal seems reasonable to me, but it is not a goal that can be achieved without painstaking, incremental improvement of the existing system.

My guess is that the existing system was designed, built and is being operated according to US Navy specifications and requirements. The team that designed that launcher could (presumably) be enlisted to design more capable launchers.

In the topic before this point, I have advocated keeping the existing technology, and simply extending the launch platform as far as can be done before something breaks. Thus, in my proposal, acceleration would stay at 2.5, and thus humans could be included in the potential use cases.

In addition, I have proposed the drive plate be attached to the vehicle being accelerated. In the case of an aircraft, as proposed by NASA (see Post #5 of this topic), I would envision the drive plate permanently attached to the underside of the aircraft. In addition, I would NOT limit the system to a single track, but would instead distribute the load over as many tracks as the designed vehicle could accommodate.

Finally, your most welcome reinforcement for the use of EML from the Moon and other airless bodies is supportive of initiatives offered in the Asteroid mining topic, as well as several others that can be found in the archives.

I would like to see the EML topic develop into one or more working systems. It will take support such as yours to enable that to happen.

(th)

Last edited by tahanson43206 (2020-04-09 07:22:35)

elderflower · 2020-04-11 03:10:29

The problem with attaching the driver to the payload (aside from the need to provide a new one for every shot) is that the payload/vehicle becomes more massive. In the case of a military aircraft that means a reduction in fuel/range or armament. In a moon based unit it would mean that you have to decelerate the extra mass to enter earth orbit or reenter the atmosphere. If you discard the driver you still have to provide a new one with every shot and you will need to control the fate of each discarded item to prevent it becoming a bit of a nuisance.
By decelerating and retaining the driver you will increase the complexity of the EML installation a bit, but you will improve its operational effectiveness.

tahanson43206 · 2020-04-11 06:10:28

For elderflower re #180

Thank you for engaging on this (to me, important) subtopic. I agree there are tradeoffs. Indeed, until I came along, there appears to have been no one who even thought about incorporating the drive plate in the vehicle to be accelerated.

I would like to offer two suggestions for a designer to consider in thinking about launches with integral acceleration plates.

First, in the case of a winged vehicle such as proposed by NASA in 2009 (See Post #5 of this topic for details), the mass of the plate (as I understand it right now) is small compared to the mass of the vehicle and payload, and re-use of the drive plate makes as much sense as re-using the wings or wheels or the fuselage itself. In that situation, the drive plate(s) would be fitted to the fuselage in such a way they can be replaced when they become unusable due to the stress imposed upon them by the acceleration process.

For the category of low-G vehicles, such as those carrying passengers or cargo from the Moon, the drive plate is completely reusable because the vehicles themselves will complete their deliveries and then either return to the Moon, or become part of the payload. The aluminum alloy of the drive plate is likely to be highly valued as a deliverable, suitable for construction directly (flat plate) or melted down to create countless subsequent objects.

In terms of using a recoverable sled, the prior work along that line is available for review, if anyone would like to pursue that option.

Certainly the existing EML on the Gerald R. Ford is an example of a fully recoverable driver. However, that system is designed for a specific function that does not necessarily equate to the 10 G launch as envisioned by kbd512, or the 2.5 G launch I've been proposing.

In the case of the 2.5 G launch from the Moon described earlier in this topic, the launch track would require 71 miles (114 km). To design a recovery subsystem means that the designer is accepting a vehicle travelling at Lunar escape velocity which is already heavily stressed by the trip through the accelerator, and (presumably) the sled would be decelerated at a rate far greater than 2.5 G's. However, the ability to accelerate or decelerate anything at greater than 2.5 G's has not been demonstrated on Earth, to the best of my knowledge, with the sole exception of reports of rail gun performance at significantly higher levels, and in that case, the "sled" is incorporated in the "vehicle", and deceleration is accomplished by impact at the destination.

Thank you again for helping to develop this topic.

kbd512 set this topic into motion with a fairly ambitious vision. It will take some effort by a small army of folks to bring any element of that vision to pass in coming decades.

(th)

Last edited by tahanson43206 (2020-04-11 06:11:53)

kbd512 · 2020-04-11 08:06:48

tahanson43206,

Now there's an interesting thought. If we had an Aluminum smelter and electron beam welder in orbit, then we could reuse the entire body of the upper stage as part of a habitat module. Maybe that's the key. Instead of having the factory here on Earth, we put it in orbit and make the parts up there using material that would otherwise be dumped into an ocean.

tahanson43206 · 2020-04-11 08:19:18

For kbd512 re #182

Thanks for encouragement of the concept of re-using elements of the launch vehicle on orbit.

I'm about to post a paper by a local PhD candidate on possible design of a robust computer architecture that falls back to earlier times for inspiration.

While the paper was written for application on Earth for security purposes, I am picking up on it as particularly interesting for off-Earth communities.

I'll definitely be interested in your comments.

(th)

kbd512 · 2020-04-11 09:12:47

tahanson43206,

Simplicity, robustness, and security are even more important for off-world computer-controlled systems. Any sort of computer flight control system should be as simple and robust as possible for long duration space flight or repeated reuse. In decades past, we built avionics hardware to function like lego bricks that each added discreet capability to the overall system. Software integration made both hardware and software control inordinately more complicated for the capabilities provided. An all-in-one system sounds great until you run into a design flaw or software bug. Many corporations and other entities that write general purpose computer operating systems release software updates on at least a monthly, if not weekly, basis to address software design or implementation flaws. That may not work very well for an interplanetary transport system.

I read about a blast from the past a couple of days ago that made reference to using high-powered microwaves to turn ordinary liquid water into plasma to achieve specific impulses up to 800 seconds in laboratory thruster test articles. Easily storable H2O could provide the impulse propulsion to break orbit, followed by more efficient ion engines for cruise propulsion.

PERFORMANCE EVALUATION OF THE MICROWAVE ELECTROTHERMAL THRUSTER USING NITROGEN, SIMULATED HYDRAZINE, AND AMMONIA - A Dissertation in Aerospace Engineering by Daniel E. Clemens

Design of a Water-Propellant 17.8-GHz Microwave Electrothermal Thruster - by Sergio Gallucci, Michael Micci, and Sven G. Bilén

All of those bubbas came out of Penn State.

Orbitec did some work for NASA on AMET (Advanced Microwave Electrothermal Thruster) under a SBIR grant a few years back, but I think that company is rolled into Sierra Nevada Corporation / SNC (the people working on Dream Chaser).

We can send up the water propellant and the Aluminum for vehicle fabrication at the same time. Instead of paper thin hulls, we can have 1 to 2 inch thick hulls with Aluminum Whipple shields. Furthermore, Orbitec worked on a special type of rocket engine that didn't require regenerative cooling because the engine induced a special kind of combustion instability in the chamber that cooled the walls of the chamber and nozzle throat. Their Vision VR-3A engine was a 30,000lbf thrust class liquid propellant engine and I think it was actually made from Aluminum combined with a RCC nozzle extension but that was years ago and my memory of it is not so great now. Anyway, I seem to recall their engineer or scientist or someone who worked there who said that you could actually touch the wall of the rocket engine with your bare hand while it was firing and not get an instant 3rd degree burn from doing that. They were working on a 65,000lbf class LOX/LH2 engine and a 75,000lbf LOX/RP-1 engine some years ago. No idea what progress was made, but the Air Force and NASA were funding it.

tahanson43206 · 2020-04-11 11:26:48

For kbd512 re #184, computer hardware for space flight, and water plasma propulsion ...

I'm planning to read the articles you cited.

My first reaction was to think that 800 seconds sounds like an impressive number if the amount of thrust is substantial.

If you had one of NASA's 10 Kw compact sterling cycle nuclear power plants to work with, what thrust do you think could be achieved?

You alerted the forum reader to expect low efficiency, so I'll be looking for that. Depending upon the availability of water for a particular flight plan, there might be a useful trade to be made. A robot space craft might shift back and forth between using water (plasma) and ion propulsion depending upon what works best when. The power source wouldn't care what was consuming it's output.

A nice benefit of a propulsion package that depended only on water is that there is plenty to be found in a variety of locations in the Solar System.

Edit#1:
SearchTerm:PlasmaThruster
SearchTerm:WaterPlasmaThruster

(th)

Last edited by tahanson43206 (2020-04-14 09:12:32)

kbd512 · 2020-04-12 05:21:21

tahanson43206,

The thrust level associated with converting water to plasma using high-powered microwaves is substantial. It's not a traditional microwave thruster such as VASIMR, but Isp is also much lower than an ion engine like VASIMR, which is why I said it's an impulse engine for impulsive maneuvers such as breaking orbit. A low-thrust, high-Isp system such as VASIMR is required for continuous / cruise propulsion. Since this is an interplanetary transport ship, my thought process is that real ships should always be under power, not merely coasting to their destination.

I'm not sure a 10kW reactor provides much in the way of useful output, apart from exploration of a planetary surface or sending probes to the outer planets using ion engines. In the inner solar system, where solar radiation is abundant, it makes far more sense to use solar power in space. The scaling laws that NASA used to determine when switching to nuclear makes more sense than scaling up solar arrays applies to the rigid panels such as ATK's MegaFlex / UltraFlex systems. All the way out to the main belt or so, the new thin film arrays consume very little mass for the power they produce and batteries or super capacitors can store the energy required for the impulsive maneuvers that require megawatts of power for a handful of minutes.

The 10kW KiloPower reactors' Stirling cycle engines convert something like 40kWt to 10kWe, so they're only 25% efficient. A Brayton cycle might achieve 40% efficiency or so. That isn't even close to the amount of power required for impulse or cruise operations, so even though we'd carry a few of these units to the surface to supply backup or mobile power, there's really no utility to activating one aboard the ship. A single reactor won't supply sufficient emergency life support power for 5,000 people. If nuclear power is desired for the interplanetary transport ship, then it really needs to be a multi-MW design. A 4MWt core design based upon KiloPower technology would be about the size of a 55 gallon drum, but it would be many times heavier. At that power level, using a Brayton cycle makes a lot more sense to limit the mass of the radiator solution.

All that said, a very simple mechanical system with no electronics (it's obviously producing electrical output, but contains nothing more sophisticated than electric motors and generators) such as KiloPower, which essentially has 2 moving parts (the control rod and its electric motor), unless we count the Stirling engine power converter pistons as moving parts (they're not essential for safe operation- the entire coolant system can be hacked off a reactor operating at full power and it won't melt down), is inherently more reliable than massive banks of batteries and solar panels that produce highly variable output. By design, their surface-area-to-volume ratio is too high to melt down (which also means they're not very efficient). However, fission reactors are unaffected by dust reduction of solar radiation levels and day / night / seasonal cycles / latitude of the area of operations. The technologies that go into them have been proven to operate reliably for decades on end. For a smaller power supply for a mobile base or exploration operations, they're ideal for use on Mars. To support thousands of people, something much larger is required.

tahanson43206 · 2020-04-12 07:12:25

For kbd512 re #186

This slot is reserved for reply to your thoughtful post.

Thanks for taking up my question about the 10 Kw reactors. I'm intrigued by your comparison between impulse thrust and the sustained thrust of an ion engine.

SearchTerm:Continue

Edit#1: downloaded the pdf at the second link

First impression ... Oh! this is for cubesats ... water is examined as a substitute for traditional gases such as helium

Edit#2:
2020/04/14 Notes on Pdf per kbd512 800 ISP Plasma from water

Presented at the 35th International Electric Propulsion Conference
Georgia Institute of Technology • Atlanta, Georgia • USA
October 8 – 12, 2017
Sergio E. Gallucci 1 , Michael M. Micci 2 , and Sven G. Bilén 3
The Pennsylvania State University, University Park, PA, 16802, United States

We report on recent efforts to advance water-propellant-based microsatellite electric
propulsion using the Microwave Electrothermal Thruster (MET). This thruster uses
microwave power at 17.8 GHz for plasma production within a resonant cavity. Water is
utilized as the propellant, unlike previous MET models that have used helium, ammonia, and hydrazine decomposition products.

My interest in this work is NOT for a microsatellite application, although I understand that there is a significant economic interest in progress in support of microsatellite station-keeping.

Instead, I am looking to see if this technology can be scaled up, and if so, what limits may control how it is used, and what efficiency might be expected.

Conclusion: This paper appears to cover the history of development of microwave thrusters over a number of decades. It shows where work is needed, but I did not find evidence the concepts under discussion have reached practical deployment.

Numerous challenges confronted by engineers attempting to work with these ideas were described in some detail, and a fairly comprehensive list of needs for future were were provided.

I saw no evidence these ideas can be scaled up.

Edit#3: Downloaded the pdf at the first link.

This much longer document contains many more pages and quite a bit more detail, including tables of ISP for various gases and devices.

(th)

Last edited by tahanson43206 (2020-04-14 18:50:52)

SpaceNut · 2020-06-11 18:48:58

tahanson43206 wrote:

The success of the EML (ElectroMagnet Launch) system on the Gerald R.Ford is of great interest to some members of the forum.
Here is a report on a challenge facing the builders as the Ford continues launching aircraft.
https://www.yahoo.com/news/navy-carrier … 43984.html
(th)

With the need to have this device work each time and when ever its needed. We can not continue to use this launch system until the technology materials advance further to the reliability that we need from it.

But for other uses we can afford to have it breakdown as its not as critical that it works every time.

SpaceNut · 2020-12-03 21:08:50

Here is the small launcher system.

SpaceNut · 2021-11-18 21:21:38

We mentioned this in the topic SpinLaunch conducts first successful test of giant 'suborbital accelerator' satellite sling

The device works on the same principle as a sling: placed in a vacuum chamber on a rotating arm that's accelerated by a small rocket to hypersonic speed, it lets go of the payload at just the right moment, sending it soaring upward on its accumulated momentum.
Yaney said the first test involved a one-third scale suborbital accelerator running at just 20% capacity. Still, the device towers some 300 feet above the New Mexico desert, meaning the final SpinLaunch system is anticipated to be some 900 feet tall.
Everyday Astronaut, a single rocket launch can pump out tons of noxious pollutants, including carbon dioxide, carbon soot, carbon monoxide, nitrogen oxides, chlorine, alumina and sulfuric compounds. Moreover, it costs up to $5,000 per pound to lift an object into space on a rocket.
However, even if the system is capable of putting a small satellite into orbit, it's unlikely to ever supplant a rocket launch, the SpinLaunch's payload is measured in pounds; by comparison, SpaceX's Falcon 9 rocket can lift more than 15 tons on a reusable flight and 22.8 tons on an expendable flight, lifting as many as 143 small satellites at once.
At its largest, SpinLaunch expects its payloads to be no more than 440 pounds (200 kilograms). The company gave no estimate as to the cost per launch.

kbd512 · 2021-11-18 21:37:55

SpaceNut,

SpinLaunch could deliver our steel cannon balls to orbit. A robotic tug in orbit could then collect them for transfer to an interplanetary cargo frigate headed to Mars. Something like this is ultimately the correct path for low cost space flight, not for passengers, but for the millions of tons of raw materials required to build-out civilization on another planet.

tahanson43206 · 2021-11-19 05:20:37

For kbd512 re #191, and for SpaceNut re #190

Nice Work! Thanks!

Part of the carbon composite heat shield would be consumed on the way up through the first 20 miles, just as would be true for a "traditional" surface based launcher. The balance would be consumed in the arrival at Mars.

The challenge of precision guidance remains. Perhaps ** that ** is included in the SpinLaunch package. The SpinLaunch package would necessarily need to include a solid fuel rocket for horizontal velocity to achieve orbit, and ** that ** would include a guidance subsystem. That guidance subsystem could be designed to guide the package on it's flight through the atmosphere of Mars. It might use X-Y ailerons for the purpose.

All-in-all, this seems quite promising.

(th)

SpaceNut · 2022-01-22 22:29:45

Radian Aerospace comes out of stealth and raises $27.5M for orbital space plane development

Reminds me of the SLI (space launch Iniative)
AASWH0w.img?h=768&w=1366&m=6&q=60&o=f&l=f

Radian was going after the “Holy Grail” of space access with a fully reusable system that would provide for single-stage-to-orbit (SSTO) launches.
Radian’s executives argue that technological advances have now brought the SSTO vision within reach
Radian has been working on rocket engine development at its Renton headquarters and at a testing facility near Bremerton, Wash. Ars Technica reported that the liquid-fueled engine is designed to provide about 200,000 pounds of thrust, and that the space plane would be powered by three of the engines. The current design would support carrying up to five people and 5,000 pounds of cargo into orbit, Ars Technica reported.
Radian says its space plane, called Radian One, would make sled-assisted takeoffs and airplane-like runway landings, with a turnaround time of as little as 48 hours between missions.

Sound like what we are proposing

RGClark · 2022-03-09 08:12:35

SpaceNut wrote:

Radian Aerospace comes out of stealth and raises $27.5M for orbital space plane development
Reminds me of the SLI (space launch Iniative)
https://img-s-msn-com.akamaized.net/ten … 60&o=f&l=f
Radian was going after the “Holy Grail” of space access with a fully reusable system that would provide for single-stage-to-orbit (SSTO) launches.
Radian’s executives argue that technological advances have now brought the SSTO vision within reach
Radian has been working on rocket engine development at its Renton headquarters and at a testing facility near Bremerton, Wash. Ars Technica reported that the liquid-fueled engine is designed to provide about 200,000 pounds of thrust, and that the space plane would be powered by three of the engines. The current design would support carrying up to five people and 5,000 pounds of cargo into orbit, Ars Technica reported.
Radian says its space plane, called Radian One, would make sled-assisted takeoffs and airplane-like runway landings, with a turnaround time of as little as 48 hours between missions.

Sound like what we are proposing

What do you mean "we"?

Bob Clark

GW Johnson · 2022-03-09 09:29:34

Bob:

Glad to see you're still with us. Hadn't seen anything from you here or on your site for months now. Worried about you.

GW

Calliban · 2022-03-09 09:58:46

Power is the problem with any electrically driven launch concept. Depending on the size of the vehicles, you need to deliver 10's to 1000's GJ of energy to the device in a matter of seconds. That power is expensive: it means either huge generating capacity feeding the device, or enormous banks of flash capacitors, flywheels, hydraulically powered generators, etc. It is one of the reasons why I examined the steam cannon as a launch assist option a while back. You can charge up a hot rock energy store slowly and discharge it by forcing water into it using a positive displacement pump. Launch velocity is limited to about 500m/s. But the system is achievable in ways that a higher velocity EM system is not, because of the peak power problem. EM launch may be a better system for launch assist of smaller vehicles. But it requires dividing payloads in a way that introduces other inefficiencies.

Last edited by Calliban (2022-03-09 10:04:36)

RGClark · 2022-03-09 10:52:57

GW Johnson wrote:

Bob:
Glad to see you're still with us. Hadn't seen anything from you here or on your site for months now. Worried about you.
GW

I had been investigating other topics unrelated to space. But the announcement of the Radian Aerospace SSTO venture piqued my interest. I'll start a separate thread on it discussing the SSTO aspects.

Robert Clark

Terraformer · 2022-03-09 11:53:14

Calliban,

You can also use a gas gun. Hydrolox should be able to provide quite the kick. Not enough to reach orbit, but a few km/s maybe?

tahanson43206 · 2022-03-09 17:50:16

For Terraformer re #198

There ** is ** a topic devoted to light gas gun technology. It has been thoroughly tested and proven effective and feasible.

http://newmars.com/forums/viewtopic.php … 70#p151970

That topic has been languishing because it never received the support I think it deserves.

If you would like to help to expand and grow the topic, I'd appreciate your support.

The method used (per Dr. Hunter) is not combustion, but rather heating of hydrogen using a method not yet revealed.

The system can certainly reach orbit ...

You'll find a smart aleck post by a then member of the forum.

The system designed by Dr Hunter would use a solid fuel rocket to achieve LEO. However, it is ** not ** necessary to bother with LEO if the goal is to deliver payload to escape, which would be helpful if supplies were intended for Mars, or other Solar System destinations.

(th)

Mars_B4_Moon · 2022-05-19 13:21:06

Chinese satellite propulsion startup secures funding as country’s constellation projects grow
https://spacenews.com/chinese-satellite … ects-grow/
A Chinese satellite electric propulsion company has secured multi-million yuan angel round financing amid a proliferation of Chinese constellation plans.

Kongtian Dongli (“Aerospace propulsion”) was established in March 2022. The round was led by Jinshajiang Hongyu and MiraclePlus, according to Chinese media reports.

The company’s main products are Hall thrusters and microwave electric propulsion systems, with an on-orbit test of the latter planned before December this year.

Few entities are engaged in propulsion for small satellites in China, but the demand for such systems is apparent.

China has established a state-owned enterprise to manage a national satellite internet constellation of up to 13,000 satellites. China SatNet has been engaging with commercial companies as it develops a blueprint for constructing the “Guowang” constellation.

Notably, these and other small satellites will be required to have onboard propulsion to reduce the chances of collision and mitigate the issue of debris in low Earth orbit.

A “notice on promoting the orderly development of small satellites” (Chinese) issued in May 2021 states that small satellites should be capable of collision avoidance maneuvers, as well as lowering orbits following the end of missions. State departments may take relevant “appropriate measures” if a company does not track, report on, and deorbit its satellites.

A number of commercial actors, sometimes in partnership with state-owned groups, are also developing low Earth or

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#176 2020-04-07 17:29:15

Re: electromagnetic launch with microwave propulsion

#177 2020-04-08 23:42:41

Re: electromagnetic launch with microwave propulsion

#178 2020-04-09 03:30:58

Re: electromagnetic launch with microwave propulsion

#179 2020-04-09 07:22:03

Re: electromagnetic launch with microwave propulsion

#180 2020-04-11 03:10:29

Re: electromagnetic launch with microwave propulsion

#181 2020-04-11 06:10:28

Re: electromagnetic launch with microwave propulsion

#182 2020-04-11 08:06:48

Re: electromagnetic launch with microwave propulsion

#183 2020-04-11 08:19:18

Re: electromagnetic launch with microwave propulsion

#184 2020-04-11 09:12:47

Re: electromagnetic launch with microwave propulsion

#185 2020-04-11 11:26:48

Re: electromagnetic launch with microwave propulsion

#186 2020-04-12 05:21:21

Re: electromagnetic launch with microwave propulsion

#187 2020-04-12 07:12:25

Re: electromagnetic launch with microwave propulsion

#188 2020-06-11 18:48:58

Re: electromagnetic launch with microwave propulsion

#189 2020-12-03 21:08:50

Re: electromagnetic launch with microwave propulsion

#190 2021-11-18 21:21:38

Re: electromagnetic launch with microwave propulsion

#191 2021-11-18 21:37:55

Re: electromagnetic launch with microwave propulsion

#192 2021-11-19 05:20:37

Re: electromagnetic launch with microwave propulsion

#193 2022-01-22 22:29:45

Re: electromagnetic launch with microwave propulsion

#194 2022-03-09 08:12:35

Re: electromagnetic launch with microwave propulsion

#195 2022-03-09 09:29:34

Re: electromagnetic launch with microwave propulsion

#196 2022-03-09 09:58:46

Re: electromagnetic launch with microwave propulsion

#197 2022-03-09 10:52:57

Re: electromagnetic launch with microwave propulsion

#198 2022-03-09 11:53:14

Re: electromagnetic launch with microwave propulsion

#199 2022-03-09 17:50:16

Re: electromagnetic launch with microwave propulsion

#200 2022-05-19 13:21:06

Re: electromagnetic launch with microwave propulsion

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