The Advanced CCD Imaging Spectrometer on the Chandra X-ray Observatory: twenty-five years of on-orbit operation

TL;DR

This paper reviews the 25-year on-orbit performance of the ACIS instrument on Chandra, highlighting its durability, scientific contributions, and lessons learned for future X-ray observatories.

Contribution

It provides a comprehensive overview of ACIS's operational history, performance evolution, and insights for designing long-lasting space-based X-ray instruments.

Findings

ACIS continues to perform well after 25 years.

Performance changes are manageable and do not limit instrument lifetime.

Lessons learned inform future instrument design and operation.

Abstract

As the Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory completes a quarter century of on orbit operations, it continues to perform well and produce spectacular scientific results. The response of ACIS has evolved over the lifetime of the observatory due to radiation damage, molecular contamination, changing particle environment, and aging of the spacecraft in general. We present highlights from the instrument team's monitoring program and our expectations for the future of ACIS. Performance changes on ACIS continue to be manageable, and do not indicate any limitations on ACIS lifetime. We examine aspects of the design and operation of ACIS that have impacted its long lifetime with lessons learned for future instruments.