In our solar system, earth. God put earth right where its not too hot or too cold. Humans are very fragile when it comes to temperature. All the others are either too cold or too hot. Also earth is the only one that we know of that has an atmosphere in which we can breath.
You wouldn't feel anything; you would die in a matter of seconds due to the lack of oxygen.
Earth can be studied in detail, but through the use of equipment like telescopes we can study the other planets in our solar system without the use of spacecraft.
We haven't sent any spacecraft to Betelgeuse, it is much too far. However, the Hubble Space Telescope has studied Betelgeuse, so I guess that counts.
Venus was the planet that the spacecraft Magellan enabled scientists to research extensively.
When spacecraft like the Hubble telescope enter a planet's orbit, it is lifted by a rocket. Once it enters the orbit, the rocket drops away and the spacecraft is projected through the planet's orbit.
The three main stages in exploring a planet are: 1. send out a spacecraft that passes one or more bodies in space without orbiting them. 2. study a planet over a long period of time. and finally, 3. land instruments on a planet or to send instruments through its atmosphere.
Satellite
Voyager 2
No sadly not. It is the only planet not (when this answer was written) planed to be studied by spacecraft. Poor Uranus.
a doctorinmay
No spacecraft has visited all the planets.
We haven't sent any spacecraft to Betelgeuse, it is much too far. However, the Hubble Space Telescope has studied Betelgeuse, so I guess that counts.
The First spacecraft was the MESSENGER. The First spacecraft was the MESSENGER.
Billions.
Venus was the planet that the spacecraft Magellan enabled scientists to research extensively.
The Mariner spacecraft landed on the planet Mars, and the Apollo spacecraft landed on the moon.
Saturn
yes
The presence or absence of spacecraft near Mars will have no effect whatsoever on the planet's gravitational field.