The most common and most likely answer to this crossword clue is the 4 letter word ROOM
I've seen this crossword clue in The Times
R
O
O
M
More clues leading to the result ROOM
- Curry, not the first, in space
- Aussie native taking tea with male fellow lodger
- Fell back in space
- Australian jumper, male, finds space
- Space dock found in ascent
- Fell, turning over in space
- Opportunity to tie up
- Drive around? No time or opportunity
- Opportunity for newly-weds to get undressed?
- Space for bear’s friend to get married
Buddy explains!

The straight part
We know that "Space" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case space = room.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ROOM mean?
ROOM noun- Opportunity or scope (to do something).
- Space for something, or to carry out an activity.
- A particular portion of space.
- Sufficient space for or to do something.
- A space between the timbers of a ship's frame.
- Place; stead.
- A separate part of a building, enclosed by walls, a floor and a ceiling.
- (with possessive pronoun) (One's) bedroom.
- (in the plural) A set of rooms inhabited by someone; one's lodgings.
- (always in the singular, metonymy) The people in a room.
- An area for working in a coal mine.
- A portion of a cave that is wider than a passage.
- A IRC or chat room.
- Place or position in society; office; rank; post, sometimes when vacated by its former occupant.
- Furniture sufficient to furnish a room.
- To reside, especially as a boarder or tenant.
- To assign to a room; to allocate a room to.
- Wide; spacious; roomy.
- Far; at a distance; wide in space or extent.
- Off from the wind.
- A deep blue dye.