Nasa’s proposed plasma rocket would get us to Mars in 2 months

https://gizmodo.com/nasa-pulsed-plasma-rocket-advanced-concept-mars-1851463831

by genman • 2 years ago

88 92 2 years ago

devbent• 2 years ago

Shorter periods of exposure to space radiation and microgravity could help mitigate its effects on the human body.

Of course once astronauts are on mars they will still be exposed to radiation, until some sort of shielding can be built.

Which would be an obscene undertaking, and involves moving lots of raw and refined materials to mars.

Which means hopefully the price of this rocket to get stuff off of earth is dirt cheap, because moving squishy humans to Mars, no matter the speed, is not the limiting factor! (Getting humans to Mars and keeping them alive there is!)

sandworm101• 2 years ago

> obscene undertaking, and involves moving lots of raw and refined materials to mars.

Or they can dig a hole and/or pile mars dirt on top of their living structures. Some materials are better than others at absorbing radiation but, as a general rule, mass/depth of the protection counts more than composition.

dyauspitr• 2 years ago

Building an underground chamber doesn’t seem like an impossible undertaking. Alternatively, maybe mars already has caves and tunnels.

OnlyMortal• 2 years ago

There are tunnels that appear to have been created by volcano lava. Lava tubes.

heavyset_go• 2 years ago

It takes a lot of energy to displace sand/dirt/rocks to build anything underground. Human-powered shovels require a lot of food and water, and machinery requires combustion and a lot of hydrocarbons.

ortusdux• 2 years ago

I still think that this would explain Musk's dalliance with tunnel boring machines.

malfist• 2 years ago

The easiest solution is to set up shop in a cooled volcano tube

dmurray2• 2 years ago

Most of the materials could surely be found on Mars. A shelter built out of sandbags would be a low tech solution that would get you a large part of the way there.

Further, Mars itself shields you from half the radiation (at night), the Martian atmosphere shields you from a little more, and Mars is further away from the Sun on average than an Earth-Mars spaceship.

Radiation during transit really does seem like a bigger issue.

pmontra• 2 years ago

There are also cosmic rays. They come from every direction, so even at night.

An experiment measured that kind of radiation about 20 years ago https://en.wikipedia.org/wiki/Mars_Radiation_Environment_Exp...

lupusreal5• 2 years ago

It's not an intractable problem, just send a robot bulldozer and excavator a few years beforehand. The real problem with a Mars colony is the economics for making it anything more than a small scientific outpost / political stunt. Forget the upfront cost of the habitat/etc, how do you actually create a self sustaining Martian economy? I've never heard a realistic answer for this.

mongol• 2 years ago

It is an interesting problem of energy. How would a robot bulldozer or excavator be powered? They require more power than a rower.

rendall3• 2 years ago

how do you actually create a self sustaining Martian economy? I've never heard a realistic answer for this.

What would a realistic answer even look like? I imagine that since nothing like jump-starting an economy ex nihilo on a cold, desert planet has been done before, any proposal at all would sound wildly unrealistic.

kallistisoft• 2 years ago

As far as I know the plan has always been to use the martian regolith and water as primary radiation shielding -- same as the moon.

Here is a recent (2022) paper[1] on the concept, but you can easily find scholarly work on this going back many decades...

[1] https://www.sciencedirect.com/science/article/abs/pii/S00320...

ceejayoz6• 2 years ago

https://en.wikipedia.org/wiki/Martian_lava_tube have also been proposed as pre-existing possible shelters.

https://en.wikipedia.org/wiki/Caves_of_Mars_Project#/media/F... "HiRISE image of Mars hole 'Jeanne', about 150 meters (492 feet) across and at least 178 meters (584 feet) deep."

phkahler• 2 years ago

> Of course once astronauts are on mars they will still be exposed to radiation, until some sort of shielding can be built.

Send tunnel boring machines. There a company making electric ones.

TheDudeMan• 2 years ago

"hopefully the price of this rocket to get stuff off of earth is dirt cheap"

This is not a launch technology.

JumpCrisscross13• 2 years ago

Not with that attitude!

JumpCrisscross13• 2 years ago

Zubrin gave a great talk in 2011 on VASIMR, another drawing-board nuclear magneto-plasma propulsion technology [1]. It's not only untested and unnecessary, but gets used by opponents of space exploration as a convenient reason to delay funding until the magic kit is ready.

[1] https://www.youtube.com/watch?v=myYs4DCCZts

perihelions3• 2 years ago

I love the idea of nuclear fission space propulsion. But, this concept doesn't look even mildly realistic. The first fission-electric rocket in space isn't going be f'ing 10 gigawatts [0]: it's going to be 5-6 orders of magnitude smaller, it's going to be conservatively designed and cautiously iterated, in a way that gets useful engineering data even if it doesn't work the first time (it won't). This craziness is an Nth-of-a-kind iteration you might consider attempting, >20 years* after your 1st success, after >20 years of sustained development effort. It's not a near-future plausibility.

*(Coincidentally, the first serious project was cancelled about 20 years before the present day [1]. That would have been an interesting alternate history...)

[0] https://www.howeindustries.net/ppr

[1] https://en.wikipedia.org/wiki/Jupiter_Icy_Moons_Orbiter

edit: To explain my reasoning a little: 10 gigawatts is gigantic amount of violently destructive energy—thermal energy, radiation energy, mechanical and vibrational [2] energy—you're trying to squeeze into a lightweight, complex, mass-optimized aerospace device that needs to run unattended and without maintenance for many years, without failing. That's probably very hard to get right. There have been many nuclear electric reactors in space already, but remarkably none of them, in operation, had any moving parts! They were all solid-state thermoelectric converters. I believe the bulk of that design choice boils down to "it's simple and conservative". Thermoelectrics aren't impressive by any other metric—just simplicity.

Even the first, smallest nuclear electric turbine in space will be a majorly impressive achievement, for whoever succeeds at it.

[2] Let's not forget: https://en.wikipedia.org/wiki/Galileo_project#High_gain_ante...

CaptainOfCoit• 2 years ago

This craziness is an Nth-of-a-kind iteration you might consider attempting, >20 years* after your 1st success, after >20 years of sustained development effort. It's not a near-future plausibility

Fittingly, the project is part of NIAC (NASA Innovative Advanced Concepts) which is specifically for borderline outlandish, far-future ideas like magnetic sails, space elevators, nuclear propulsion, a "Lunar Crater Radio Telescope" and many other somewhat crazy ideas.

From NASA:

The NASA Innovative Advanced Concepts (NIAC) Program nurtures visionary ideas that could transform future NASA missions with the creation of breakthroughs — radically better or entirely new aerospace concepts

https://www.nasa.gov/stmd-the-nasa-innovative-advanced-conce...

senectus1• 2 years ago

completely agree, except one thing. If we shift manufacturing to space from space mined/sourced resources we care a lot less about mass optimization.

mr_toad3• 2 years ago

The rocket in question is a nuclear thermal rocket, not a nuclear electric rocket. The 10GW figure refers to waste heat.

The reason for pulsing the engine, and the advantage over a normal nuclear thermal rocket is that the heat generated by operating at full power continuously would be unmanageable.

https://en.wikipedia.org/wiki/Pulsed_nuclear_thermal_rocket

https://www.euronuclear.org/glossary/pulsed-reactor/

akira25014• 2 years ago

The distance between Mars and Earth is not fixed and is on a multi year repeating cycle.

So, do they mean 2 months at the minimum distance, or the maximum?

JumpCrisscross13• 2 years ago

do they mean 2 months at the minimum distance, or the maximum

This is a high delta-v vehicle, so anything on the outside of the porkchop [1].

[1] https://en.wikipedia.org/wiki/Porkchop_plot

akira25014• 2 years ago

I'm not understanding how that plot applies here or how it answers the question.

pmayrgundter• 2 years ago

Good.

But it's only a few days with a million ISP from fusion.. let's raise the bar ;)

trhway• 2 years ago

my napkin gets almost the same with existing and relatively simple tech - solar or nuclear source of energy powering ionic drive (as the one already made and tested/flown by NASA with 3500 Isp (vs. yet to be made 5000 mentioned in the article)). Solar can actually beat nuclear if it is made as very thin, ie. light, film. I think and hope that SpaceX would end up using solar+ionic combo instead of chemical for Mars (and nuclear + ionic for beyond Mars).

ChrisMarshallNY• 2 years ago

The AppleTV+ alternate history show, For All Mankind, works on the theory that we got the NERVA engine working.

According to that show, we should have been on Mars for the last twenty years.

credit_guy• 2 years ago

could allow for crewed missions to Mars to be completed within 2 months. As it stands today with commonly used propulsion systems, a trip to Mars takes around 9 months.

Both numbers are pulled out of thin air. The Hohmann transfer time between 2 planets is about half a year. Which year, you ask? The year of the inner planet, or of the outer planet. Well, it's the average of the 2 years. A Martian year is about 2 of our years, so the average is 1.5 years, divided by 2 it's 9 months.

But if you are willing to burn more fuel, you can cut down the travel time. The delta-v between Earth orbit and Mars is surprisingly low. From the Moon transfer orbit to the low Mars orbit it is 2.5 km/s. The rule of thumb is that a rocket can achieve twice the delta-v of its exhaust velocity. In the case of the SpaceX Starship, the exhaust velocity is 3.7 km/s, twice that is 7.4 km/s, about 3 times the delta-v needed for the Hohmann transfer. SpaceX states they will be able to get to Mars in 6 months [1]. Musk went further and claimed that the Starship could get to Mars in as little as 80 days, and this fantastic Stack Exchange post [2] explains that maybe 80 days is slightly too optimistic, but 90 days is doable.

Now this design here claims that the rocket can achieve an ISP of 5000 seconds, which means an exhaust velocity of 50 km/s. With such an exhaust velocity, basically they can pick any random number and claim they can get to Mars that fast. The shortest path between the two orbits, the radial one, is about 75 million km long. At 50 km/s, it takes 1.5 million seconds, or 17 days. Of course, this is for a one-way trip, but presumably in the far future we could preposition fuel in Mars orbit for the return trip.

Maybe they thought half a month will sound too wild, so they went for the 2 month number to make it sound more realistic. The problem is that compared to the 3 months doable by SpaceX, it's not all that impressive.

[1] https://www.spacex.com/humanspaceflight/mars/

[2] https://space.stackexchange.com/questions/57568/elon-musks-i...

Nasa’s proposed plasma rocket would get us to Mars in 2 months

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