How does a spacecraft change course?
Luckily, space is pretty empty and we know the locations of the large objects in it fairly well, so the chances of DS1 accidentally hitting something are small. There are small objects in space we don't know the exact location of, though, so it is possible. If that happened, DS1 would very likely be destroyed.
The systems in DS1 are very fragile. They were made to be used in the vacuum of deep space and not to come into contact with anything, so there is no protective shielding against blows from anything in space. The smallest article in space would collide with DS1 at a very high speed, doing a lot of damage.
Virtually anything bigger than golf ball would probably destroy DS1, and something smaller could easily cripple the spacecraft so that it cannot fulfill the rest of its mission. On space flights with people on board, many systems have backups, so that if there is some unexpected problem the mission won't fail. But on DS1 there are no backups, so if one system fails there is no way to repair it or get another system to do its job. DS1's systems are interconnected, which means that a blow that crippled a solar panel would mean that communications, AutoNav, and Remote Agent would not get power. These systems would fail and others would fail as well in a chain reaction of sorts. Or, likewise, if MICAS were destroyed, AutoNav wouldn't work and the ship could go off course, making the solar panels less useful, etc. Since many systems on DS1 are experimental, we don't know exactly how they would fail.
What is AutoNav?
How does DS1's communications system work?
What happens to a ship when it runs out of power?
What is a remote agent?
What new technologies are being tested on DS1?
How do scientists know what the path of an object in space will be?
What is in space?
What is MICAS?
How do we know what's in space?