How long would it take to travel to the Sun with current space technology?

Currently, with the chemical propulsion technology we have, we can talk about propulsion speeds in the order of 3.8–4.5 km/s or 13,680–16,200 km/h.

And here there are three answers. Even because the distance from the Earth to the Sun is not always the same.

• Minimum distance = 147 million kilometers
• Average distance = 149 million kilometers
• Maximum distance = 152 million kilometers

In this case I will use 16,200 km/h.

$s=dt\to t=ds$

$tmin=147,000,000km16,200km/h$

$tmin\approx 1,03years$

$tmandd\approx 1,05years$

$tmthex\approx 1,07years$

Therefore, taking into account an acceleration of 1g so as not to put too much pressure on the crew, and our current propulsion capacity, the journey from Earth to the Sun would always take just over a year.

Yes. We could theoretically reach speeds of 200,000 mph if we used an ion thruster, once the spacecraft was well out of Earth's orbit. But that would require the thruster to have a nuclear reactor.

And the time needed to reach this speed of 320,000 km/h would depend on the mass of the ship and the capacity of the reactor.

Although it is not a recommended trip since we would have to make the spaceship have a lot of mass, because of the radiation protection material that we would have to use.

Because without this material the crew would be making a one-way trip.

The ideal would be something with some similarities to Project Orion, which would allow the creation of a nuclear thruster that would allow the spacecraft to reach at least 1% of the speed of light.

Because at 1% of the speed of light then the travel times would be very different:

$tmin\approx 5days$

$tmandd\approx 6days$

$tmthex\approx 6days$

And these would be the days when it would not be good to try to reach 1% of the speed of light in seconds. In fact, it would be fatal for the crew.

If you tried to accelerate a spaceship from, say, an initial velocity of zero to, say, 2,997,924 m/s in 20 seconds, you would be exposing the crew to a G-force of approximately 15,264g. More than enough to kill the entire crew, and destroy the ship.