Essentially the goal is this: to use a giant electromagnetic launch track to accelerate a hypersonic aircraft to Mach 1.6. The aircraft would then separate from the track, ignite its engine and enter near space at seven times the speed of sound.
Does no one read the article anymore before commenting? I’m not responding to all the comments here since it’s clearly a waste of my time, but every single one of the concerns that people mention in this thread so far has been acknowledged in the article already.
@yogthos article says Mach 7.
This is not a serious space launch proposal. Nowhere near fast enough. It’s the sort of suborbital malarkey that Branson is doing.
Orbit or GTFO.
This is completely different from what Branson is doing which is tourism for rich people. The proposal here is to launch large planes to the edge of atmosphere for rapid transportation.
@yogthos So not “launching hypersonic planes into space” then, but a horizontal catapult for feeble rockets.
Assume this is just to save an SST having to spend fuel getting up to low supersonic speed, and then it lands as a glider.
There are lots of designs for engines that work from stationary to hypersonic speed, which are air breathing, and have the advantage of being able to take off from runways.
If you bother reading the article you’ll see that the motivation here is to save fuel. It’s a lot cheaper to use an electromagnetic launcher to launch the plane.
@yogthos Not when you then have to expend shit tonnes of delta V turning the plane to face the right way because you can’t just take off from a normal runway and turn to face the right direction at a normal speed, like normal planes can.
This is the aviation equivalent of a gadgetbahn. Someone saw Top Gun and got stupid ideas about scaling up steam catapults, didn’t they?
Yeeting planes is not new. The reasons we don’t do it in civil aviation have not changed.
I love how you think you know more about the subject than the actual engineers building this stuff. 😂
@yogthos @goatsarah Thing is: This idea is not new. People have thought about it for a long time. And in the end they all came to the same conclusion: it isn’t worth it.
Thing is that the west stopped making any ambitious engineering projects. The idea isn’t new, but the will to put these kinds of things in practice doesn’t exist outside of China.
It smells like tech bro nonsense, doesn’t it?
Save fuel is it? Ok, put it on a train. Water in the way? Put it on a boat. They’re super efficient.
@yogthos also, how much fuel are you using transporting shit to your yeeter, driving past a few dozen perfectly good airports en route?
@yogthos @goatsarah You would had to enter hypersonic regime at ground level to even have got the possibility to reach the edge of space. Just imagine the sonic boom from that … Also think about the thermal protection that would be needed for your device to withstand the air friction.
Again, I’m sure actual engineers designing this stuff have in fact thought about these things.
@yogthos Sadly the article is behind a paywall, so I have to make some educated guesses. This idea has got multiple problems. First thing is that especially when you want to transport people (like said in the article), the g-load is really limited. This means that your rail gun would had to be incredibly long to speed up the plane to a significant speed. Remember that you need to travel at 25,000 km/h to stay in orbit.
But even when you sped up to such a speed, you would experience a ton of drag because of the air resistance. It is only feasible to really speed up in higher regions (> 70-80km). So you would need some kind of first stage that had to carry some kind of a second stage to that region, so that it could accelerate from there. But this is exactly the concept that is used by rockets like the Falcon9/Falcon Heavy or Rocket Labs Electron, who all perform a stage separation in that region and perform a RTLS or controlled splash down to recover the first stage.
Also you would had only a single possible orbit here. But in reality there are a bunch of different interesting orbits out there.
Then just think about the costs. Just calculate how much launches with systems like the F9 or the upcoming Neutron you would have to perform, to even reach the break even point.
here’s a full article so you don’t have to speculate https://archive.ph/KbL8c
@yogthos The link sadly doesn’t work.
since it works for me, here’s the text from it
People could soon be launched into space using a type of hypersonic rail gun, as Chinese scientists and engineers combine the significant advances made in recent years in both electromagnetic launch and hypersonic flight. Essentially the goal is this: to use a giant electromagnetic launch track to accelerate a hypersonic aircraft to Mach 1.6. The aircraft would then separate from the track, ignite its engine and enter near space at seven times the speed of sound. This space plane, a behemoth weighing 50 tonnes and measuring longer than a Boeing 737, is part of the “Tengyun project” unveiled in 2016. Relying on the plane’s own power for lift-off would require a huge amount of fuel. And to ensure safety during a low-speed take-off, scientists and engineers have had to make compromises in aerodynamic design and engine layout that affect high-speed flight efficiency. But, while in the past such projects did not get past the discussion phase, this time it is different. China is putting words into action. And scientists working on the project are confident the various issues can be solved.
“Electromagnetic launch technology provides a promising solution to overcome these challenges and has emerged as a strategic frontier technology being pursued by the world’s leading nations,” the team, led by scientist Li Shaowei with the magnetoelectric general department of China Aerospace Science and Industry Corporation’s (CASIC) Flight Vehicle Technology Research Institute, wrote in a peer-reviewed paper published in the Chinese academic journal Acta Aeronautica on February 6. Putting theory to the test To test the theory, CASIC, one of China’s foremost aerospace and defence contractors, has constructed a 2km (1.2 mile) low-vacuum track high-speed maglev test facility in the industrial heartland of Datong, Shanxi province.
This facility can propel a heavy object to speeds approaching 1,000km/h (620mph)– close to the speed of sound. In the coming years, the length of the test line will be extended to achieve a maximum operating speed of 5,000km/h. This is the most ambitious electromagnetic propulsion facility on the planet, poised to support the development of next-generation high-speed railways and gather vital scientific and engineering data for the space electromagnetic launch project. Meanwhile in Jinan, capital of the eastern Shandong province, another giant maglev track to support ultra high-speed electromagnetic sled experiments is also up and running, under the supervision of the Chinese Academy of Sciences (CAS).
Nasa’s failure to launch China is not the first country to propose an electromagnetic space launch system. Such concepts have been floating around since the Cold War era. In the 1990s, Nasa tried to bring this idea from paper to reality, with the first step being the construction of a mini test line measuring 15 metres (49 feet). However, due to insufficient funding and technical difficulties, the actual length of the completed track was less than 10 metres. Eventually, the project was scrapped, and government and military leaders redirected resources towards the development of low-speed electromagnetic catapult technology for aircraft carriers instead. But the USS Ford, the first aircraft carrier to be fitted out with this new technology, has been plagued with issues. During Donald Trump’s presidency, he complained that the actual performance of the electromagnetic catapults was far inferior to that of their traditional steam counterparts. The US Navy has also publicly acknowledged that the excessively high failure rate of the Ford’s electromagnetic catapult system has resulted in reduced combat capability for the entire carrier strike group. Due to significant setbacks in electromagnetic launch technology, the US military has abandoned the development of some related projects, such as rail guns, and shifted the saved funding to hypersonic missiles. Now, China has picked up the relay baton handed off by America. Nonetheless, Li and his colleagues are being cautious.
Computer simulations, wind tunnel tests In the early stages of their research, they uncovered a startling omission by Nasa: no wind tunnel tests were ever conducted to ascertain the viability of detaching the space plane from its track. Nasa’s original idea was that accelerating the space shuttle to just 700km/h would be enough to eliminate the need for a first-stage rocket, but Chinese scientists believe this speed is too low. However as the speed increases, the airflow between the aircraft, the electromagnetic sled carrying it and the ground track becomes very intense and complex. So one of the first things the project team must confirm is that the aircraft will be able to safely separate from the track. To this end, Li’s team has conducted extensive computer simulations and wind tunnel tests. Their findings have revealed that as the aircraft breaches the sound barrier, numerous shock waves ripple along its underside, colliding with the ground and generating a cascade of reflections. These shock waves introduce airflow disruptions, carving out pockets of subsonic airflow amid the aircraft, electromagnetic sled and track.
When the sled then hits its target speed, releases the aircraft and brakes abruptly, the chaotic airflow initially buoys the craft, only to transition into a downward thrust after four seconds, according to the wind tunnel test result. If there were passengers on board, they might experience brief dizziness or weightlessness. But as the distance between the aircraft and the track increases, the intensity of the airflow diminishes until disappearing completely. Accompanied by the roar of the engine, the aircraft then enters a rapid climb phase. Certain sections of the craft require reinforcement to withstand the reflected shock waves. Further real-world tests are also needed. But overall, this approach is safe and feasible, Li’s team wrote in the paper.
China’s advantages in rail gun research In the realm of electromagnetic space launch systems, China is ahead of the game, with some clear advantages that other nations lack. Major defence players like CASIC have already produced their own hypersonic weapons which are now part of the People’s Liberation Army (PLA) arsenal – and generate an income for their creators. Plus, China is ahead in electromagnetic rail gun research, having made breakthroughs including high-performance power supplies, precision control technology, wear-resistant coatings and the development of electronic devices capable of resisting strong electromagnetic interference. China’s robust manufacturing sector can also supply the world’s finest and most cost-effective rare earth permanent magnets or superconducting wires for high-speed maglev tracks. Numerous cities, eager to build high-speed maglev trains, are ready to invest. And following Elon Musk’s discontinuation of Hyperloop One last year, China stands alone in its commitment to advancing this technology. While SpaceX’s reusable rockets have slashed satellite launch costs to US$3,000/kg, some scientists have estimated that an electromagnetic space launch system could drive those costs down to a mere US$60/kg.
@yogthos So the system just accelerates to Mach 1.6, then the system had to use its own fuel to speed up to just Mach 7. But Mach 7 is just a fraction of the needed velocity to get into orbit. Mach 7 is around 8,500 km/h. But you need 25,000 km/h to stay in orbit. So you need an additional stage to accelerate to that speed. And that stage would had to be expendable, otherwise you couldn’t carry enough payload.
Still you can only reach a single orbit. To reach another orbital plane, you then would had to use a lot of additional propellant to perform a dogleg maneuver to switch to a different plane.
BTW: This whole idea reminds me of SpinLaunch. Prototypes are already built by the U.S. based company with the same name. They want to accelerate small launchers in a vacuum chamber, so that in the end they can carry up to 300kg in a low earth orbit.
But the goal isn’t to stay in orbit. The goal is to push the plane to upper atmosphere where there is low air resistance, and then it mostly glides to where it needs to go. The article very clearly explains that the goal is to create an alternative to long range flights instead of doing space launches. I’m also familiar with SpinLaunch, and it’s a completely different purpose where they want to launch small satellites into low Earth orbit.
@yogthos The articles ends in “While SpaceX’s reusable rockets have slashed satellite launch costs to US$3,000/kg, some scientists have estimated that an electromagnetic space launch system could drive those costs down to a mere US$60/kg.”
This is a comparison to a launch into an orbit.
This tech can be used for both purposes, but most of the article discusses transportation. Once China puts this tech in production, I’m sure it will be used for orbital launches as well.
“Could soon” is doing an awful lot of work there.
I could soon have an pony.
Works for me
Just Like Evergrand
Sure, that will be for “planes” and definitely not for long range hypersonic cruise missiles.
