The FIREBall-2 UV balloon telescope: 2018 flight and improvements for 2020

Keri Hoadley, Erika T. Hamden, Bruno Milliard, Aafaque R. Khan, Simran Agarwal, Zeren Lin, David Schiminovich, Gillian Kyne, Jean Evrard, D. Christopher Martin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


The Faint Intergalactic-medium Redshifted Emission Balloon (FIREBall-2, FB-2) is designed to discover and map faint UV emission from the circumgalactic medium around low redshift galaxies (z ∼ 0.3 (C IV); z ∼ 0.7 (Lyα); z ∼ 1.0 (O VI)). FIREBall-2's first launch, on September 22nd 2018 out of Ft. Sumner, NM, was abruptly cut short due to a hole that developed in the balloon. FIREBall-2 was unable to observe above its minimum require altitude (25 km; nominal: 32 km) for its shortest required time (2 hours; nominal: 8+ hours). The shape of the deflated balloon, as well as a concurrent full moon close to our observed target field, revealed a severe, off-Axis scattered light path directly to the UV science detector. Additional damage to FB-2 added complications to the ongoing effort to prepare FB-2 for a quick re-flight. Upon landing, several mirrors in the optical chain, including the two large telescope mirrors, were damaged, resulting in chunks of material broken off the sides and reflecting surfaces. The magnifying optical element, called the focal corrector, was discovered to be misaligned beyond tolerance after the 2018 flight, with one of its two mirrors damaged from the landing impact. We describe the steps taken thus far to mitigate the damage to the optics, as well as procedures and results from the ongoing efforts to re-Align the focal corrector and spectrograph optics. We report the throughput of the spectrograph before and after the 2018 flight and plans for improving it. Finally, we describe several methods by which we address the scattered light issues seen from FIREBall-2's 2018 campaign and present the current status of FB-2 to fly during the summer campaign in Palestine, TX in 2020.

Original languageEnglish (US)
Title of host publicationUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXI
EditorsOswald H. Siegmund
ISBN (Electronic)9781510629295
StatePublished - 2019
EventUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXI 2019 - San Diego, United States
Duration: Aug 11 2019Aug 13 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXI 2019
Country/TerritoryUnited States
CitySan Diego


  • CGM
  • Galaxy Evolution
  • Optical Alignment
  • Scientific Ballooning

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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