Is Interstellar Travel Possible with Current Propulsion Technology?

[dfinch]

Let's say a ship is beyond Earth's meaningful gravity pull, and has solar panels. Assume that it can collect solar power and use it in a system which blasts propellant away from the ship to accelerate through space. The ship's goal is to leave the solar system and reach a new star, but to continue accelerating for half the distance, and decellerating the remainder, versus just drifting at a constant velocity. To me, this gives us two options:

1. The ship must leave our solar system with enough propellant to continue accelerating. This seems problematic because for every kg of propellant it takes with, the mass grows, negating the benefits of bringing the propellant with.

2. The ship must collect propellant along the way. This seems problematic because the ship is unlikely to encounter an appropriate amount of propellant along its linear path, or to solve the logistical problems associated with capturing them at high speed.

This makes me think it's unlikely we could ever build a ship capable of propelling to another star.

I hope my thinking is flawed?

 

[Doug Huffman]

See Bussard Ramjet. Even at Earth, solar irradiation is only 1350 Watts meter^-2

 

[Drakkith]

It's extremely unlikely that any interstellar ship will continually accelerate halfway and then decelerate. The amount of fuel required is staggeringly huge. Gathering fuel on the way probably won't work either, as the interstellar medium is not very dense and the faster you're traveling, the less effective this method is. You'll slow down when you gather the fuel since the fuel has to accelerate up to your speed. The faster you go, the more energy this takes.

 

[mfb]

This makes me think it's unlikely we could ever build a ship capable of propelling to another star.

We can. The Voyager and Pioneer probes are doing exactly this and New Horizons will follow them. They are just all way too slow for practical purposes and won't stay active long enough.

There are concepts that would allow significantly higher speeds - up to ~10% the speed of light, that would allow to reach the nearest stars in decades. Most of them use fission or fusion (some even consider antimatter) as their high energy density allows high exhaust velocities. Some use sail-like structures that would rely on a beam sent from the solar system. See Project Longshot and the various links in the navigation box at the bottom, or Category:Interstellar travel.

 

[pmacias]

I can understand your concerns about the feasibility of interstellar travel with current propulsion technology. However, I believe there are a few important points to consider.

Firstly, while it is true that the mass of the ship will increase with the addition of propellant, there are ways to mitigate this issue. One possibility is to use a propulsion system that does not require carrying a large amount of propellant, such as a solar sail or a nuclear propulsion system. These technologies are still in development, but they have the potential to greatly reduce the amount of propellant needed for interstellar travel.

Secondly, while collecting propellant along the way may seem like a daunting task, it is not impossible. In fact, there are already missions in place, such as the Deep Space 1 spacecraft, that have successfully demonstrated the use of ion propulsion and have collected propellant from the solar wind. Additionally, future advancements in technology may allow for the harvesting of resources from other celestial bodies, such as comets or asteroids, to provide propellant for interstellar travel.

Lastly, it is important to remember that space is vast and there are many potential avenues for interstellar travel that we have yet to explore. For example, utilizing gravitational slingshots or using the energy of a star as a propulsion source could greatly reduce the need for propellant.

In conclusion, while interstellar travel with current propulsion technology may seem challenging, it is not impossible. With continued research and advancements in technology, I believe that we will one day be able to build a ship capable of reaching another star. It may not be in the near future, but as scientists, it is our job to push the boundaries of what is possible and continue to explore the vastness of space.