For example, this question is very time-bound:
What landings beyond Mars and the Moon are scheduled? (asked 15 June 2016)
In a few years parts of the answer will be obsolete, and new missions will be come available.
How do we handle such a moving target?
Edit a date in (into the title?), allowing it to 'settle down', maybe resulting in a follow-up question one year later...
Don't do anything, allow future edits to update the answer accordingly (strikethrough or delete obsolete items?)..
Other?
This particular question is a rare instance of a list question that is acceptable to our community, even though it will change with time. It covers material not easily found elsewhere and of use for gauging the state of an important part of the field. List questions are generally frowned upon on SE, but each SE site is different and needs to establish its own approach to them.
Community Wikis are the only reasonable way to handle the list questions that meet our standards. They are specifically meant to be edited by many people, and the usual rule of preserving author intent doesn't hold. They allow everything to be in one answer, which is the only way a list can be kept organized and clear.
Ideally, people will maintain that answer with new information as it becomes available. If that peters out, then it remains a reference point for the status of deep space missions at the time when it was last edited - taking into consideration it also makes a point of stating the list may be incomplete.
The date when something was asked and when an answer was last edited is shown on all questions. Maybe it is worth considering adding some special cautionary note to the text of that answer to ensure readers take note of the date of the last edit and if it is old bear in mind the list is likely outdated. I haven't thought of a really good way of doing that. Putting it in the title of the question doesn't strike me as the right place. I think it would be a bad idea to start asking the same question more than once, and wouldn't want to encourage that by dating a question explicitly that way. Spreading the same information across a series of questions sounds like a great way to make it harder to find and incomplete.
The question can be considered a bit of a test case. I believe there are a few other list questions in our library, but can't think of one and don't know how I might search for other examples. It would be good to get further input on this matter.
For reference, here is a current list of questions with time-sensitive lists (or that could have lists).
This list may be incomplete:
What are the choices today for orbital mechanics simulation software?
Full list of asteroids that have been optically imaged as of 2013 (Time-sensitive because: 1. We may discover later that something we imaged in 2013 is an asteroid. 2. Maybe this shouldn't be restricted to 2013.)
How many astronauts have reported an alien encounter of some kind?
Flight testing before manned flights: what are various countries' requirements?
What are the best places to go to research a space exploration matter online (in depth)?
How many satellites/probes will or have travelled outside the solar system?
How many active or inactive artificial satellites are in Mars orbit?
How many and/or what kind of animals have ever been on the ISS?
How many extraterrestrial bodies have hosted a "lander" which returned images?
One thing to note about this list is that all the questions are positively scored (with a 3 or above), and a few are among the highest rated on our site.
A suggested answer template for such questions...
Because the answer to this question is likely to change over time, I have created a community wiki answer. Feel free to contribute to it now and in the future.
edit this section for aspects that won't change over time
edit this section for what applies now
