Just how preferable are afternoons for flying Ingenuity? What are the reasons?
Ingenuity relies on its solar arrays to charge collect and store the electrical power needed to fly, to keep the vehicle alive, and to operate the avionics. Keeping the vehicle alive (e.g., heaters) represents the largest power drain. Flying represents the most intense power ...
Historical TLEs show that the space telescope was deployed at a height of 570 km (blue curve):
The graph also shows that the altitude was not too low at decommissioning (black line, ~470 km) leaving low budget and/or low fuel as the only possible culprits.
The quick decay of the telescope was due to the high solar activity associated with solar cycle 24 (...
Very good question!
In Space there is no air to put thrust on any other thing to expect any action-reaction forces.
You are right, there is not much to push on. In low Earth orbit there is a very tiny amount of air left. It's not very useful to use to maneuver much, but it's enough to gradually lower the orbits of anything up there.
So orbiting spacecraft ...
The lower the orbit, the higher the drag. Since the drag force is roughly proportional to area, but the resulting acceleration is force divided by mass, then the denser the spacecraft, the less it is affected by drag.
The simplest way to fight drag is to carry a lot of fuel, and use it often. This will make the spacecraft less dense as the tank empties, ...
Surprisingly, the moons of Jupiter are one of the worst places in the solar system to have a settlement, especially if it's a waystation to somewhere else. The reasons aren't entirely obvious.
The difficulty of getting to Jupiter
The moons of Jupiter are hard to get to, not only because you have to do some significant climbing out of the Sun's gravity well ...
If we discount photos of Hayabusa 2 such as this taken by its own cameras:
Image taken 4 seconds before touchdown with CAM-H
(image credit: JAXA).
then the only image I could find of the Hayabusa 2 from one of its rover/hoppers is this:
Image captured by Rover-1A (Minerva-II1) on September 21 at around 13:08 JST.
This is a color image taken immediately ...