# Can a liquid be used to de orbit debris?

Can a liquid be used to slow a satellite to loose orbit by adding or taking momentum from a satellite, a type of devise that releases a liquid that expands and solidified adding surface area making more drag and or by adding weight?

• What's the point? Instead of carrying N kg of solids up, you now have to transport N kg of liquids, which is more difficult (sloshing etc)
– user1569
Nov 25 '18 at 10:18
• This question has been flagged for closure, but I'm voting to leave it open. Satellites are on-topic, and the question is clear (especially after the latest edit), it's just lacking in basic knowledge of physics and is of little value to our site. The correct response is not to close, but to downvote. As the DV text says: "This question does not show any research effort; it is unclear or not useful". Nov 25 '18 at 23:52

Temperature is not the only factor for matter phases, pressure does make a difference too.

As space is practically a vacuum, thus pressure is zero. As far as I know, there can be no liquids in the vacuum of space. No element nor compound is liquid in zero pressure no matter what the temperature might be. The best candidate for this would be Helium, but even in this case the vacuum of space cannot keep equilibrium between liquid and gas phases, and thus all liquid helium will evaporate into gas.

Liquid could exist in space, if it would be able to collapse on its own gravity and maintain gaseous atmosphere bound to the liquid body. This would require way more matter than is feasible for your purpose, however.

EDIT: Also adding mass to an orbiting object does not in general cause its orbit to decay, as mass does not significant role in orbit equation. Gravitational force IS proportional to product of masses, but then again acceleration is force divided by mass - ie it gets cancelled out; applies only if adding mass does not significantly change the barycenter of said two objects (ignoring relativistic effects and gravitational waves since obviously far outside the scope of this question)

Adding surface area does not affect orbit in vacuum since there is no drag nor friction. Also shape of the object does not matter for the very same reason.

EDIT 2: As noted in comments, liquids may remain liquids in vacuum long enough for this scenario. I couldn’t find very good references how this might look like in the vacuum of space, but seemingly water can exist as a liquid for extended periods of time in very low pressures, see eg https://www.hou.usra.edu/meetings/lpsc2014/pdf/2060.pdf which states that 250ml of liquid water did fully evaporate in about 2.5 hours in 0.003 arm (Personally I find this very surprising and contradicting to my prior knowledge but I have been wrong many times before)

• There is Mercury.
– Muze
Nov 22 '18 at 22:19
• Space is very cold in general. Also the same equilibrium between liquid and saturated gas applies to other elements and compounds than Helium Nov 22 '18 at 22:25
• Then maybe something more like a snow ball?
– Muze
Nov 22 '18 at 22:29
• Edited my answer to include explanation about mass and surface area and their effect on orbit. Changing orbit with snow balls is in theory doable, but then again orbiting snowballs are about as dangerous as space debris. Nov 22 '18 at 22:38
• I think matter with very low triple-point pressure can become liquid enough long to reach the satellite. And I think the idea is not very bad, the problem with it that there is no way to splash that liquid to the satellite from the Earth. Nov 25 '18 at 0:27