I was surprised there were no references to past nuclear (fission) efforts, including a long test (more than 12.5 minutes) at 4000 megawatts of Pheobus 2A.[1]
Perhaps there are some solid or non-cryogenic liquid fuels that could take place of the liquid hydrogen and make fission based systems far more feasible in the near term.
This direct fusion drive is a really interesting concept. Maybe something like this could be used for interstellar travel in a century (or five), it is very encouraging that there is active research on it. ~5kg of thrust is not a lot, but over time...
This sounds significantly more feasible than nuclear pulse propulsion ("project orion" style) which I used to think was the only feasible approach to get to another star.
One thing that was unclear from the paper to me: How does the fusion drive "pick" D/He3 fusion over D/D? Can this be "forced" by just cranking the plasma temperature way up? Or do you still just have to deal with a bunch of neutrons from undesired D/D fusion?
Already in orbit is OTP-2, which has 2 novel drive systems, one based on non-Newtonian thrusters, and the other based on an ION drive.[1]
Edit: The latter is "Fusion enhanced"[3]
The company’s the FireStar Drive uses is a water-fueled pulsed plasma thruster that uses a form of aneutronic nuclear fusion to boost its performance.
[1] https://www.nanosats.eu/sat/otp-2
[2] https://celestrak.org/NORAD/elements/graph-orbit-data.php?CA...
[3] https://www.aerospacetestinginternational.com/news/space/roc...
Based on my experiences with Kerbal Space Program, this object seem to be almost being pushed off from solar orbit. Given its 'small' size, how much energy would be required to push it off the solar system?
Why dont they just launch a string of hundreds or thousands of tiny mesh probes out of a canon over a longer period of months or years? They dont need to be powerful if you have a big mesh network and each probe would only need to cost about what a cell phone does.
> relatively soon
If the DFD takes 10 years to get there it means it would need to be launched in 40 years. That's quite a timeline.
Amazing that an organization can keep budgeting and planning for such a long project.
Very fascinating mission idea. Given how Sedna reaches so far away (>500AU), I wonder if the flyby would also reveal some details about conditions that distant. Maybe the surface contains some unexpected molecules that could shed light on its origin and what it's like that far out.
So I'm a fan of space exploration but this one seems... a reach.
First, you can't say that any of this propulsion tech is remotely mission-ready. It's all very speculative. There's been no real-world testing of any kind. You'd need to at least test-fire it in orbit and prove a solar sail in particular. Any kind of nuclear propulsion adds whole new levels of proof-of-solution (yes I know RTGs exist but those are technically quite simple being just radioactive decay rather than something utilizing fission or fusion).
Second, it's not clear what kind of speed this could reach. At New Horizons speed, assuming you can find the right launch window, you're looking at 18-25 years transit. That's a long time for a probe to survive.
If you do adopt a solar sail, what happens to it over 20+ years? What happens from long-term damage of hitting dust and micrometeors? Could you need to course corret if it gives uneven thrust?
And all this for... a flyby. Obviously Sedna is too far and too slow for anything else. Just like Pluto.
But if we're talking 2j0-30 year missions, I'd rather send an orbiter to Uranus. About 20 years is I believe the time frame for an orbital insertion to Uranus. IIRC Neptune is closer to 30.
Sound like something out of 3 Body Problem
> Sedna is expected to pass through the perihelion of its orbit in 2075--2076 and then move again away from the Sun. Considering the distances involved, a mission targeting the object would need to be launched "relatively" soon, especially if using conventional propulsion systems, which could require up to 30 years of deep-space travel.
Sedna's perihelion is ~76 AU - more than twice as far as Pluto, which took New Horizons nearly a decade to reach.
Sedna's apehelion is over 500 AU.
> The Direct Fusion Drive rocket engine is under development at Princeton University Plasma Physics Laboratory
Is it ... is it actually working? How close are they? And even if they get it to work next year, will it be something well-engineered & reliable enough to send it into space for 10 years and expect it to work?