y is a chemical rocket incapable of getting us to our nearest neighbor proxima centauri?
Is it incapable of not getting us to our nearest neighbor proxima centauri because there isn't enough fuel in the universe to provide for the rocket?
Have you read the WIki article? it sums it up nicely. Yes, there is not enough fuel chemically to do it.
thanks
No, that is not the reason. You could get there in several thousand years with a chemical rocket, by just coasting, but everyone on board would be dead.
When going long interstellar distances in rockets, you have to achieve a very high speed. The good news is that there is a lot of time to accelerate. You do not need to have a lot of thrust, but if you want to accelerate to a large fraction of the speed of light and get there in under 100 years, you have to achieve a high spacecraft speed without having to having to exhaust a lot of mass. Such performance requires a property called "specific impulse" that is too low for chemical rockets. Specific impulse is proportional to the speed of the gas in the exhaust. With chemical rockets, the maximum chemical exhaust speed is about 3 km/s. It's too low to achieve a high enough spacecraft speed for a 'short" (under 100 years) trip. "Freezing" astronauts to prolong life may help.
Electrical thrusters that can eject propellant at a higher speed are needed. This has been an active field of development, and there are several alternatives.
thank you drwls :-)
A chemical rocket's incapability of reaching Proxima Centauri, our nearest neighboring star system, does not solely stem from a lack of fuel. While it is true that the vast distance and time required for such a journey necessitate an immense amount of fuel, there are several other significant challenges involved.
1. Speed and Duration: Proxima Centauri is located about 4.24 light-years away from Earth, which equals approximately 40 trillion kilometers. A chemical rocket's top speed is limited by the speed at which it can expel exhaust gases, usually around 40,000-50,000 kilometers per hour. Given this speed limitation, it would take thousands of years to reach Proxima Centauri with a chemical rocket.
2. Fuel Constraints: As you mentioned, obtaining enough fuel to power a rocket for such a long-duration mission is a major hurdle. To carry sufficient fuel to reach Proxima Centauri within a human lifetime would require an astronomical amount of propellant. Moreover, carrying extra fuel adds weight to the rocket, requiring even more fuel to overcome Earth's gravity during launch.
3. Energy Requirements: Even with a sizable fuel supply, the energy needed to accelerate a spacecraft to a significant fraction of the speed of light is enormously demanding. Overcoming this energy barrier would likely require breakthroughs in propulsion technologies beyond chemical rockets, such as nuclear propulsion or advanced forms of electric propulsion.
4. Life Support: For such a long journey, sustaining the crew with sufficient life support systems, food, water, and protection from cosmic radiation poses additional challenges. The long-term viability of the crew's physical and mental health would need to be addressed.
5. Maintenance and Reliability: Maintaining and repairing a spacecraft for an interstellar journey spanning generations would be extremely challenging. Ensuring the reliability of critical systems and the availability of spare parts over such a prolonged period would be highly complex.
Overall, while the fuel required for an interstellar journey is indeed a significant challenge, the limitations of chemical rockets extend far beyond solely the volume of fuel available in the universe. Advancements in technology and the development of alternative propulsion systems will be necessary to make interstellar travel a reality in the future.