https://www.science.org/content/article/history-and-mystery-surround-nasa-s-2028-nuclear-mars-mission

10 hours ago, martin-w said:

 NASA are actively working on nuclear propulsion and plan to launch a nuclear powered spacecraft to Mars by 2028. 

That's less than two years away. That seems incredibly optimistic.

1 hour ago, DD_Arthur said:

That's less than two years away. That seems incredibly optimistic.

 

It does.  Its a relatively small probe though. 

https://interestingengineering.com/space/nasa-nuclear-powered-mars-mission

 

Quote

 

• Mission Goal: To prove that nuclear electric propulsion can enable more efficient, faster interplanetary travel and support future human missions to Mars.
• Spacecraft & Technology: SR-1 Freedom will use a closed Brayton cycle fission reactor, using High-Assay Low-Enriched Uranium (HALEU) for fuel. It will combine this reactor with the Power and Propulsion Element (PPE) originally developed for the Lunar Gateway.
• Propulsion System: The spacecraft will use 6kW and 12kW Hall-effect thrusters developed by Aerojet Rocketdyne and Busek.
• Payload: The mission will carry the Skyfall helicopter trio to Mars for atmospheric exploration, building on the success of the Ingenuity drone.
• Schedule: The project, announced by NASA in March 2026, is on a tight schedule, aiming for a 2028 launch to compete in the new space race. 

 

 

 

 

 

 

Quote

 

Yes, the SR-1 Freedom mission is considered a significant challenge, largely due to its extremely tight timeline and the technical hurdles of operating a nuclear reactor in space. [1, 2]

NASA plans to launch this nuclear-electric propulsion (NEP) spacecraft to Mars by December 2028, aiming to demonstrate the first-ever use of nuclear fission for propulsion beyond Earth orbit. [1, 2]

Key Challenges and Risks:

• Extremely Aggressive Timeline: The mission must move from design to launch in less than three years, a pace experts say is very challenging for space projects.
• Engineering and Assembly: The project requires integrating a nuclear reactor with a "LEGO-like" approach—repurposing hardware intended for the canceled Lunar Gateway station.
• Thermal Management: The reactor produces immense heat that must be radiated away in the vacuum of space, requiring massive cooling radiators to keep the system from melting.
• Regulatory Hurdles: Launching radioactive material requires complex approvals from multiple federal agencies, including the Department of Energy.
• Operational Hurdles: The spacecraft must survive intense vibrations during launch, and the nuclear system must be safely activated while in space.

 

•  

Edited May 1May 1 by martin-w

Nuclear propulsion is the way, at least for now.

The cosmic radiation thing is a problem.  I have heard it proposed to shield the spacecraft with a water tank...basically have them flying along inside a big tube / water tank.   Getting back, they'd have to have the MOXIE technology x10 to get enough water & O2.   I think the radiation is the biggest problem, even bigger than propulsion.

I don't see the radiation issue being all that great of a problem.  It simply requires heavier shielding, which of course adds mass to the craft, which in turn means even more fuel.

Solving the propulsion issue is the most important thing as it also solves some of the other problems: better propulsion means less fuel and faster travel times, and less time in space is easier on the astronauts' bodies and minds.

However, even if the travel time to Mars could be cut in half, from 6-8 months to 3-4 months, I still believe the craft would need a section providing artificial gravity, as being weightless for that long would cause serious physical problems.  Moreover, even if the astronauts could get through all those months of weightlessness, isolation, and confined space, they would then be exposed to Mars' gravity of less than half that of Earth for 8-12 months, and finally the return trip to Earth of another 3-4 months.

Another obstacle discussed is that after they've reached Mars, the astronauts would then have to wait 8-12 months for the return window to Earth.   They'll have to either stay on the orbiting ship all that time, which would be an awful experience in such a confined space, or stay on the surface, either of which requires overcoming all the challenges related to resources like water, breathable air, food, medical issues, etc.

When you really think this through, it becomes evident that this is a massively challenging undertaking that we're nowhere near prepared for.

Dave

 

1 hour ago, dave2013 said:

However, even if the travel time to Mars could be cut in half, from 6-8 months to 3-4 months, I still believe the craft would need a section providing artificial gravity, as being weightless for that long would cause serious physical problems.

 

Just over 12 months is the record, on the ISS.