The charge might be too serious for you to pay by mail.
You must make arrangements on your case before you travel abroad. Don't just skip the court hearing.
In writing, request a continuance to a date certain when you will be able to attend. And, consider hiring a lawyer to be your advocate.
You can request a continuance in writing. Call the clerk and they will give you a fax number to send the letter to.
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
In addition to counsel above, if you are not scheduled for court until you get back, and your question is merely," can I leave the country with this charge outstanding?", you will have no prblem with authorities at the time you leave and the time in which you come back, but don't lie if you are asked about it. Take the citation with you to show it is not a serious charge.