Cygnus cargo ship leaves International Space Station, begins new mission in orbit

Dec 23, 2019
Two things, semi-unrelated.

First: I notice that ground controllers do an awful lot to/with the ISS. One the one hand, I'm sure some of it is helpful and takes some workload off the astronauts. On the other hand, while I know the astronauts do a lot of things that robots cannot, it must make the general public wonder why we have astronauts up there.

Second: "Once the Cygnus capsule completes its secondary mission, it will burn up in the atmosphere along with 5,800 lbs. (2,600 kilograms) of disposable cargo, or trash, that the crew of Expedition 61 packed inside."
5,800 pounds of trash! This is one of those "things that make you go hmmm." What are astronauts going to do with their trash on the moon and Mars? Just one of a myriad of things that must be addressed, but this one to me seems to be the most problematic.
Jan 31, 2020
First: Like you said, "astronauts do a lot of things that robots cannot." Foremost among these is studying the effects of spaceflight on humans. Once humans are aboard it makes a lot of sense for them to conduct experiments and maintenance tasks that it would be difficult and expensive to design robots to do.

Second: Disposable trash includes single use experimental equipment, obsolete equipment, used air and water filters, dead batteries, food and water wrappers and containers, solid human waste and its appropriate containers, used clothing (it's cheaper to send new clothing to the crew than to develop a zero-g washing machine). Think of all the trash and sewage 6 people would produce at home and work in a typical 3 months. 5000 lbs. is about right.
A moon or Mars colony will have to recycle everything. broken equipment will have to be broken down to be 3D printed into new items and human waste processed into fertilizer for growing food. These technologies are part of what's being developed on the ISS.