/sci/ - Science & Math

https://arstechnica.com/science/2006/01/2337/
>2006
Good grief has there been any updates? Didn't the HDLT autist say it basically failed during recent testing or something? Give me some good news bros

>>12261279
With manned missions you really want to crank up the delta-V budget so you can do round trips between Earth and Mars within one launch window. Send the cargo on slow boats like Starship.

>>12261300
Nuclear electric beats nuclear thermal on Isp by multiple orders of magnitude. You just need a light enough reactor and a scalable enough thrust system (read: not fucking ion drive). Use something like pic+links related that gets ~1N/kW even without superconducting magnets and has much better Isp than solid core NTR and wire it up to a plain ass 20MWe reactor. There's 2kN of thrust with no practical Ve limit at ~4 tons of propellant a DAY.

https://physics.anu.edu.au/cpf/sp3/hdlt/
http://www.researchcareer.com.au/archived-news/testing-ground-set-for-plasma-jar-to-the-stars

>>12243493
VASIMR is a fucking meme. It needs 60 megawatts of electricity to do any good. I want pic related with chilly magnets and CO2 propellant.

>>12210278
The DST concept is cool for using solar electric and hypergolics rather than exotic technology or nuclear, but 20 tons per mission is a LOT of Xenon to shit out the back of a rocket. It would be much better served with a plasma thruster system that could use more abundant fuel and is less of a power hog... especially combined with a plasma magnet sail. I really like the Helicon Double Layer Thruster for this since even without superconductors you can get it up to ~1N/kW (about 300N with DST's solar panels at Mars), and use CO2 for propellant so you can ISRU via aerobraking at Mars.

This "Helicon Double Layer Thruster" looks cool.

https://physics.anu.edu.au/cpf/sp3/hdlt/how_does_it_work.php
>Power is required only for the maintenance of plasma and the creation of the magnetic field. In our current bench top prototype, 250W is sufficient to create several milli-Newtons of thrust. In space the solenoids that generate the 250 Gauss of magnetic field this requires we estimate could be cooled to 200K, reducing the resistance in the coils by a factor of 5 and representing a power consumption of a few 10s of Watts. Relative to other existing systems this constitutes quite a power saving and is well with-in the capabilities of solar panels. The 0.5sccm of feed gas represents a mass consumption of 160 mg/hr, so that a typical 5 hour burn would use 0.8g of propellant.
http://www.researchcareer.com.au/archived-news/testing-ground-set-for-plasma-jar-to-the-stars
>“The HDLT is also really cheap. It can use all sorts of propellants and it doesn’t use much of these. We’ve tested ten types of propellants and it’s worked for all of them.
>“The HDLT can also work with carbon dioxide. So with planets like Mars and Venus where you mostly have carbon dioxide in the atmosphere, you could refuel as you go. This is a great advantage because at the moment all missions require that you carry the propellants from Earth.
>“There are also no major issues with parts or erosion. As long as you provide the power and the propellant you can go forever. So with the right development this technology might get us very, very far… and hopefully back again.”

So ~1N/kW (tens of mN from 50W) with 200K solenoids, and ISRU with cheap inert gases. This seems like it'd pair really well with a plasma magnet sail and a 1MWe fission driven Brayton engine.

>call it 0.05N from 0.05kW of power
>0.05N of thrust from 0.000160kg/hr of propellant
>scale up to 1MW
>3.2kg of propellant per hour for 1kN
That's actually insanely fucking good if it scales linearly.

This "Helicon Double Layer Thruster" looks cool.

https://physics.anu.edu.au/cpf/sp3/hdlt/how_does_it_work.php
>Power is required only for the maintenance of plasma and the creation of the magnetic field. In our current bench top prototype, 250W is sufficient to create several milli-Newtons of thrust. In space the solenoids that generate the 250 Gauss of magnetic field this requires we estimate could be cooled to 200K, reducing the resistance in the coils by a factor of 5 and representing a power consumption of a few 10s of Watts. Relative to other existing systems this constitutes quite a power saving and is well with-in the capabilities of solar panels. The 0.5sccm of feed gas represents a mass consumption of 160 mg/hr, so that a typical 5 hour burn would use 0.8g of propellant.
http://www.researchcareer.com.au/archived-news/testing-ground-set-for-plasma-jar-to-the-stars
>“The HDLT is also really cheap. It can use all sorts of propellants and it doesn’t use much of these. We’ve tested ten types of propellants and it’s worked for all of them.
>“The HDLT can also work with carbon dioxide. So with planets like Mars and Venus where you mostly have carbon dioxide in the atmosphere, you could refuel as you go. This is a great advantage because at the moment all missions require that you carry the propellants from Earth.
>“There are also no major issues with parts or erosion. As long as you provide the power and the propellant you can go forever. So with the right development this technology might get us very, very far… and hopefully back again.”

So ~1N/kW (tens of mN from 50W) with 200K solenoids, and ISRU with cheap inert gases. This seems like it'd pair really well with a plasma magnet sail and a 1MWe fission driven Brayton engine.