I rear-ended someone and received a "failure to maintain safe distance" citation. I don't believe I'm at fault and am considering challenging it in court. I don't want to get an attorney or deal with any of that, so I'm partially counting on the other guy not showing up. At the scene of the accident, the officer told me that if the other guy does not show when subpoenaed that it would be "a no-go". Am I correct in interpreting this to mean that the ticket will be dropped?
Not necessarily. Your own statements and the statements of the officer would be legally sufficient to convict you.
Also, your statement that you don't believe you are at fault is strongly at odds with a widely held interpretation of the traffic laws (not stated in the formal language of these statutes). The prevailing interpretation of the traffic laws is that you are always at fault if you rear end someone because you failed to maintain a safe distance, pretty much as a matter of strict liability and regardless of the circumstances, because a safe distance is almost by definition a distance that it is possible for you to come to a full stop from if the care in front of you suddenly comes to a stop for any reason. The only situation I can imagine where there wouldn't be liability for rear ending someone would be if you were at rest behind them at a stop light and they actively backed up into you.
In practice, almost any judge and almost any jury, would convict you of failure to maintain a safe distance if you rear ended someone absent the most extraordinary of circumstances. I honestly don't know any lawyer or likely potential juror who wouldn't convict you under these circumstances with only the testimony of the police officer and your own testimony (which you would have to offer to have any shot at avoiding a conviction) to establish that you did indeed rear end someone.
Police are allowed to lie to suspects of crimes, and often simply do not have an accurate understanding of how the legal system works. So, you are not entitled to rely on a statement made by a police officer.
Of course, it is also certainly possible that his statement is consistent with local practice in your neighborhood traffic court. So, showing up to contest the charge might still make sense, and it wouldn't be uncommon to receive a plea bargain with fewer points against your license, just for showing up to court.
The "state" is the party that "presses charges" for a traffic violation (and in fact for all crimes). For summary offenses it is sometimes the citing police officer who represents the state in court. Therefore, the police officer can use his discretion to dismiss the charges before trial, or plea bargain with you for lesser charges. Also, you can move the court for the charges to be dismissed if the officer (who is the plaintiff) misses the court hearing.
In the case of a rear-end collision, you might face a separate civil claim from the victim, or his insurer. Again, if that goes to trial, and the plaintiff fails to show up, the court may be moved to dismiss the case.