One of the more recently proven predictions, gravity waves travel at the speed of light, was the near simultaneous detection of gamma rays and gravity waves from neutron star or black hole merger. IIRC, the detections were about 2 seconds apart and the merger took place more than 100 million years ago. Another prediction, “frame dragging”, was proved in he last 15 years.
In order to get things moving really fast, you need to come up with same way of making the exhaust move really fast, maybe using lasers to heat hydrogen to say 30,000K might do the trick. At that temp, the atoms would be moving at 22,000m/s.
What SpaceX has done is to take a hit in performance to really drive down costs.
He’s only repeating the insight of a much more brilliant mind, Nobel Prize winner Enrico Fermi, dating to 1950. It’s called “The Fermi Paradox” and goes like this. The universe is much older than the sun (now estimated at 13 billion versus 4.5 billion years) which we know, because of its spectrographic composition (ratio of heavy to light elements), is a second generation star. Therefore there must have been much older first generation stars and, by implication, solar systems, some of which should have evolved intelligent, spacefaring life. Given the time spans involved, allowing for, say, one mission to another star every thousand years from about 5 billion years after the Big Bang onwards, then leap frogging outwards every thousand years from that system, repeated every thousand years endlessly and considering we 're talking about evolution being universal, creating multiple species and points of origin, the galaxy should be teeming with life and even if a particular race has died out, evidence of its existance should be obvious and all around us. So Fermi famously asked, “Where is everybody?”
To which his friend and colleague Leo Szilard replied, “They are here. We call them Hungarians”
Szilard was, himself, Hungarian, so he ought to have known.
Musk has nothing to do with Virgin Hyperloop nor HyperloopTT in America, nor with the couple of companies in Europe, nor with the companies further afield in Korea and China, but he did inspire all of them by bringing all the world’s engineers together. Branson put some money into Hyperloop One with the stipulation that it become Virgin Hyperloop.
Fermi was ahead of his time, for it is only recently that we have determined with certainty that there are many billions and billions of planets with at least some, (possibly a lot), suitable for life. For at least the past 4000 or more years, (except for the last 200), man has been moving at the speed of a horse or camel over the earth. To get to the nearest star, ( other than the sun), man has to travel in a straight line about 25,000,000,000,000 miles.
Of course, we really are moving quite fast without knowing it. The earth is spinning on its’ axis at about 1000 mph at the equator. Every year the earth travels about 600,000,000 miles around the sun at a speed of about 66,000 mph. The sun needs about 225 million years to get around the Milky Way galaxy at a speed of about 483,000 mph. From cosmic background radiation and the Doppler shift, it has been calculated that the Milky Way galaxy is also moving at about 1,300,000 mph. So traveling in the Hyperloop at 670 mph should be tolerable.
Here is an article on the Boring Company’s tunnel in Las Vegas and a look at the plan to connect the main casinos and airport. I haven’t been following what they are doing, so there could be other projects. I do know that the second round of new designs for boring machines, principally from universities, is now underway.
The Boring Company has also been trying to improve the tunneling process by holding a “Not a Boring Competition”. It had 400 applications with stated goals of increasing tunneling speed and reducing cost. On September 12, 2021, twelve finalists were selected to meet in Los Vegas and show their improvements. The finalists were:
Biggus Diggus from the United Kingdom
CU Hyperloop - U of Colorado, Boulder
Dirt Torpedo - DHBW Mosbach, Germany
Hyperloop UC - U of Cincinnati
MIT Hyperloop III - Massachusetts Institute of Technology
Paradigm Boring - U of Newfoundland, St Johns, Canada and Northeastern U, USA
Swissloop Tunneling - ETH Zurich, Switzerland
Team Badgermole - India and USA
The Diggeridoos - Virginia Tech
Warwick Boring Team - U of Warwick, United Kingdom
TUM Boring - Technical U of Munich, Germany
UMD Loop - U of Maryland
The winners were:
Safety - UMD Loop
Fastest Launch - The Diggeridoos
Innovation - Swissloop
Guidance - TUM Boring
Overall Winner - TUM Boring
You can see some pictures on the Boring Company website, but it is not clear what advances were made. Prufrock indicates some innovations.
I went to google to find out some more about the digging machines, but most of the reporting was superficial and only covered that TUM Boring was the only one to dig the complete test tunnel and was one of the few that met the safety requirements.
TUM‘s design had a four horizontal tube revolving canister,which from a picture had large tubes the diameter of the tunnel with belt conveyors inside to carry the dug material. Apparently, the tunnel boring machine has to be stopped in order to shore up the tunnel, and this canister design allows the boring machine to continue digging. So far, I have not seen exactly how well their design works.
TUM submitted a 130 page report on their machine in order to be one of the twelve selected for the final competition. They were most concerned with Swissloop who had a computerized 3-D printing machine using fiberglass and a plastic to shore up the tunnel. However, TUM had a lot of help with their machine with many corporations supplying parts and advice. In the link below, Eaton tells how they helped to automate the control of the TUM boring machine.
HerrenhnechtAG has a nice video of their tunnel boring machine with explanation of how it operates. They are from southern Germany and probably employ people who have gone to TUM. They made the 30 km high speed rail tunnel through the mountains north of Madrid, Spain using a bore diameter of 9.51 meters, 31.2 feet. They say that they can construct and operate tunnel boring machines up to 14 meters in diameter, 45.9 feet.
This tunnel boring machine is a little different in that it is a double shield type that can continue boring while erecting the segments of high strength concrete for lining the tunnel. It employs two gripper feet which push against the rock walls and absorb the thrust and torsional forces necessary for the rotating cutting head. However, when tunnel geology becomes unstable, they can’t use the gripper feet and have to stop boring while they insert the concrete sections. This slows down operations significantly.
Swissloop Tunneling came in second in Nevada only because it wasn’t able to tunnel as fast as TUM. From their remarks on Twitter, they are presently working on improving the digging head on their machine. This summer they will enter the European tunneling contest and in January 2023 in Austin, Texas, the Boring Company will hold its second contest.
They won the innovation and design award and in their link below they explain the various functions of their machine. The digging head employs a rock cutting part and water to carry away the debris. This does away with the dust associated with tunneling and which the U of Maryland had to use special switches. They use a lot of hydraulics for stearing the machine, non-stop pushing, and rotating the head. Here they had help from Hagenbuch Hydraulics in the design.
Probably the most impressive part of the design was the 3-D printing of a glass fiber and plastic tunnel tube. Their university has done 3-D printing projects in the past, but mostly with cement buildings. However, the news reports and YouTube videos don’t explain how they do the 3-D printing. It looks like they have a spool of fiberglass cloth under the first set of round rods and maybe another under the second set. Then there are rollers to hold the tube in place as it is curing. This is followed by the double hydraulic pusher which presses outward to grab the tube. You may think that the pusher should be in front of the 3-D printer. We will see what changes are made for the next competitions.