California-based startup Helicity Space has successfully raised $5 million in a recent seed funding round.
Prominent space companies Airbus Ventures, TRE Ventures, Voyager Space Holdings, E2MC Space, Urania Ventures, and Gaingels have all invested in Helicity, according to a press release.
The start-up’s work focuses on the development of nuclear fusion propulsion technology for deep space missions. Unlike traditional chemical propulsion systems, fusion propulsion offers the potential for significantly higher energy efficiency and speed.
According to their official website, "fusion produces ten million times more energy per unit mass of fuel."
As a result, fusion-powered engines might drastically reduce travel time to the Moon and, eventually, Mars, making space exploration more efficient and sustainable.
“Nuclear fusion propulsion technology is the critical missing ingredient to fast, sustainable and safe space exploration of our solar system, said Dr. Stephane Lintner, Co-founder of Helicity Space, in a press release.
The turbojet and a SUBSONIC-COMBUSTION ramjet can share the same inlet capture features, post-capture ducting, and exit nozzle, using the turbojet afterburner duct as the ramjet combustor. The caveat is that the flow through the turbojet must be entirely zeroed by the time it accelerates to about Mach 3, because otherwise, the turbomachinery and combustor cans are destroyed by the overheating. That is 100% air bypass, from ahead of the compressor face. That is not at all easy to accomplish, and so accounts for part (but not all) of the 40 year delay getting this craft done. The ramjet has a takeover speed requirement near only Mach 2.5, and is capable of taking the craft to maybe just over Mach 4 at realistic engine to frontal blockage area ratios. Those determine speed, more than any other factor.
The only flow path component that the scramjet can share with the turbojet and ramjet, is the supersonic capture feature of the inlet. It cannot share any of the post-capture ducting, because the duct geometries required are UTTERLY INCOMPATIBLE. And it cannot share the same nozzle as the turbojet and ramjet, again because the geometries are UTTERLY INCOMPATIBLE. The scramjet is basically mostly a separate, parallel-mounted flow path, sharing ONLY the supersonic capture features of the inlet with the other flow path. It has a min takeover Mach number of just about 4.
You end up with the scramjet engine flow path as a "duct shell" along the bottom of the airframe, fed by a straight(!) supersonic isolator duct fed by the supersonic capture feature. All the captured flow is fed to the scramjet, zero to the ramjet (turbojet), because above about Mach 3.5, the captured air is flame-hot if decelerated subsonic through the ramjet /turbojet post capture ducting. It is so hot it cannot be used as cooling air. The afterburner/combustor and nozzle hardware would be destroyed by the overheating, if that flow were not zeroed.
That means the ramjet/turbojet cross section can be a big fraction of the overall frontal blockage area, enabling turbojet to Mach 2.5, then ramjet to Mach 4, for scramjet takeover. The scramjet cross section is the rest of the frontal blockage area. I have VERY serious doubts about the Mach 10 claims on that scramjet. That would require it being virtually the entire frontal blockage, and that simply cannot obtain, when the turbojet/ramjet must also be there, and be a big fraction of the blockage area just to reach the Mach 4 scramjet takeover at all! I really think that's just BS. They will be quite lucky if it ever actually reaches Mach 6.
BTW, ASALM-PTV demonstrated back in 1980 that a clean aerodynamic design and a subsonic combustion ramjet that is all of the frontal blockage area actually can fly at Mach 6, without any scramjet at all! I worked on ASALM. We set that speed record accidentally, in a throttle runaway accident during the first flight test. It accelerated in ramjet (!!!) from Mach 2.5 to Mach 6, down at only 20,000 feet. It was still accelerating when it ran out of fuel at Mach 6, plus its skin was melting, since it was not designed to fly that fast. It was designed to fly only Mach 4, and that only at 80,000 feet. The other 6 flight tests were letter perfect.
That speed record was not broken until NASA's X-43A scramjet research test vehicle reached Mach 7 in its first successful test in 2004. That was rocket-boosted all the way to test speed, at a bit over 100,000 feet to limit the aeroheating to tolerable values, for a 3 second hydrogen fuel burn that did NOT accelerate in scramjet. The other successful X-43A flight was rocket-boosted to Mach 10 for a 3 second hydrogen fuel burn that did NOT accelerate in scramjet. The other attempt failed and crashed.
The USAF X-51A flights were both rocket-boosted to Mach 5 at over 100,000 feet, each for a 3-minute burn using JP-7 thermally-stable kerosene fuel (the last remaining stocks of the SR-71 fuel, actually). Neither test accelerated in scramjet. The other two attempts failed and crashed.
Given those historical facts, I think you can see why I might be rather skeptical of claims about scramjet-anything and combined-cycle-anything. I really hope Lockheed-Martin succeeds with its SR-72 thing. But I am not holding my breath about it. I think going into production is quite likely still premature. I have not seen anything about any flight tests addressing any of the potentially fatal issues I laid out just above.
Maybe my not having heard anything is due to secrecy, and maybe not. Maybe those tests still have yet to be run. If so, odds are they will be surprised and disappointed by the test results, causing yet more delay flying anything that might actually work. That’s what happened repeatedly over the last 40 years.
GW
]]>They've already built the single-engine SR-72 prototype. As near as I can tell, they're actively developing the twin engine production aircraft. It can supposedly achieve speeds of Mach 6 to Mach 10. It's a combined-cycle scramjet that uses conventional turbofans to get up to Mach 3, and then the scramjet engines take over. Lockheed-Martin's been low-key advertising it all over the place, then abruptly quit when they signed the contract for the production airframes. Did you not notice the Top Gun producers and LM executives giggling like schoolgirls when asked if the SR-72 was real? That's as close to an outright admission as you're ever going to get. As you stated, it definitely wasn't cheap, but hasn't been outlandishly expensive when compared to the F-22 and F-35. I think they're going to build 1 to 3 squadrons of these spy aircraft, which means they can be hand-built.
]]>GW
]]>The U.S. military likes nuclear power -- and I mean, it really likes nuclear power.
Powered by highly enriched uranium nuclear reactors, U.S. Navy submarines and aircraft carriers can operate for as long as 30 years before needing to add fuel.
Several months ago, if you recall, I wrote about the DRACO spaceship that NASA and DARPA -- the Defense Advanced Research Projects Agency -- were building. For $499 million, Lockheed Martin would build a small craft to test nuclear-powered spaceflight in Earth orbit, and its partner BWX Technologies (NYSE: BWXT) would build a high-assay low-enriched uranium (HALEU) nuclear engine and provide the fuel to power it.
The DRACO project is expected to launch in late 2025 or early 2026 and begin testing in 2027. Before this project has even gotten off the ground, however, it turns out that Lockheed is already working on another nuclear spaceship project.
Dubbed the Joint Emergent Technology Supplying On-orbit Nuclear Power -- "JETSON" -- project, this is a relatively small bet on nuclear power's potential in space. In total, AFRL is doling out only $60 million -- $33.7 million for Lockheed, and a bit less than that split between Intuitive Machines and Westinghouse.
In June of last year, if you recall, NASA and the U.S. Department of Energy awarded a total of $15 million to these same three companies (plus a few other partners working with them) to draw up plans for a 40-kilowatt mini nuclear power plant. As the government explained at the time, that would be enough electricity to power about 30 average American homes...or one lunar outpost, once Project Artemis gets around to building one on the moon.
NASA and the former Soviet space program spent decades researching nuclear propulsion during the Space Race. A few years ago, NASA reignited its nuclear program for the purpose of developing bimodal nuclear propulsion — a two-part system consisting of an NTP and NEP element — that could enable transits to Mars in 100 days. As part of the NASA Innovative Advanced Concepts (NIAC) program for 2023, NASA selected a nuclear concept for Phase I development. This new class of bimodal nuclear propulsion system uses a “wave rotor topping cycle” and could reduce transit times to Mars to just 45 days.
The proposal, titled “Bimodal NTP/NEP with a Wave Rotor Topping Cycle,” was put forward by Ryan Gosse, the Hypersonics Program Area Lead at the University of Florida and a member of the Florida Applied Research in Engineering (FLARE) team. Gosse’s proposal is one of 14 selected by the NAIC this year for Phase I development, which includes a $12,500 grant to assist in maturing the technology and methods involved. Other proposals included innovative sensors, instruments, manufacturing techniques, power systems, and more.
How it works — Nuclear propulsion essentially comes down to two concepts, both of which rely on technologies that have been thoroughly tested and validated. For Nuclear-Thermal Propulsion (NTP), the cycle consists of a nuclear reactor heating liquid hydrogen (LH2) propellant, turning it into ionized hydrogen gas (plasma) that is then channeled through nozzles to generate thrust. Several attempts have been made to build a test this propulsion system, including Project Rover, a collaborative effort between the U.S. Air Force and the Atomic Energy Commission (AEC) that launched in 1955.
While NEP concepts are distinguished for providing more than 10,000 seconds of Isp, meaning they can maintain thrust for close to three hours, the thrust level is quite low compared to conventional rockets and NTP. The need for an electric power source, says Gosse, also raises the issue of heat rejection in space — where thermal energy conversion is 30 to 40 percent under ideal circumstances. And while NTP NERVA designs are the preferred method for crewed missions to Mars and beyond, this method also has issues providing adequate initial and final mass fractions for high delta-v missions.
This is why proposals that include both propulsion methods (bimodal) are favored, as they would combine the advantages of both. Gosse’s proposal calls for a bimodal design based on a solid core NERVA reactor that would provide a specific impulse (Isp) of 900 seconds, twice the current performance of chemical rockets. Gosse proposed cycle also includes a pressure wave supercharger — or Wave Rotor — a technology used in internal combustion engines that harnesses the pressure waves produced by reactions to compress intake air.
When paired with an NTP engine, the Wave Rotor would use pressure created by the reactor’s heating of the LH2 fuel to compress the reaction mass further. As Gosse promises, this will deliver thrust levels comparable to that of a NERVA-class NTP concept but with an Isp of 1400-2000 seconds. When paired with a NEP cycle, said Gosse, thrust levels are enhanced even further:
In addition to propulsion, there are proposals for new reactor designs that would provide a steady power supply for long-duration surface missions where solar and wind power are not always available. Examples include NASA’s Kilopower Reactor Using Sterling Technology (KRUSTY) and the hybrid fission/fusion reactor selected for Phase I development by NASA’s NAIC 2023 selection. These and other nuclear applications could someday enable crewed missions to Mars and other locations in deep space, perhaps sooner than we think!
NASA thinks US needs nuclear-powered spacecraft to stay ahead of China
This is classic NASA saying we can no do it with what we have.
]]>6 crew with a 40t mars lander
4 crew with a 20t mars lander
first the smaller the crew is the harder to justify the large heavy pressurized rover unless we ditch the open rover and extra items that are hidden to support this function.
Also notice the habitat is nearly all of the landing capability by its self and for a small crew connect the tunnel to the rover and use that as the spreading out space to help keep peace of mind...
There also seems to be an error in the ISRU Plant only needed 1 versus 2 for the 6 to 4 crew are reversed...
Mission to Mars: How to get people there and back with Nuclear Energy
]]>bump just to add link
]]>Artificial Gravity at 8.2 m
Moon 0.16 7 rpm
Mars 0.38 12 rpm
Earth 1.00 18 rpm