Dear Colleagues,

The current and future science of SOFIA is exciting and compelling, but the Decadal Survey on Astronomy and Astrophysics 2020 report (Astro2020 Decadal report) placed SOFIA into a static box that misses the tremendous scientific growth SOFIA has experienced over the past two years. Because SOFIA is on an inflection point in science return, it is appropriate for SOFIA to continue on its path for Senior Review.

The Astro2020 Decadal report recognizes the importance of the far-infrared (far-IR) wavelength range for studies in astrophysics. The next generation Great Observatories program, with its associated technology and mission architecture maturation plan, includes an IR/far-IR observatory. A new probe line offers an opportunity to compete for a far-IR probe that would be operational in the early 2030s. For the next decade, SOFIA will continue to be the only far-IR observatory that provides access to the astronomical community to advance exploration. SOFIA will prepare the astronomical community both scientifically and technologically for this ambitious future. It advances the science by directly addressing one-third of the Astro2020 Decadal report science priorities. Moreover, the community can exploit the opportunity SOFIA provides to train the next generation of astronomers and instrument builders who will define, develop, and use the future far-IR space observatories described in the Astro2020 Decadal report. 

SOFIA’s efficiency and science productivity are on the right trajectory for SOFIA to achieve its full scientific potential. All the recommendations from the Flagship Mission Review (NASA’s 2019 review of SOFIA) have been addressed. SOFIA is now delivering on NASA’s investment with scientific payoff. There has been an outpouring of amazing science results from SOFIA ranging from the Earth to high-redshift galaxies. 

  • SOFIA has doubled its annual science publication rate over the past three years. 
  • NASA’s Astrophysics Advisory Committee (APAC) applauded recent efforts to improve the scientific productivity of SOFIA in their letter for the March 2021 meeting
  • SOFIA’s observing time is increasing over time. In our Cycle 10 Call for Proposals, to be executed from October 2022 to September 2023, the number of research hours increases by 50% from Cycle 7 and the number of Southern Hemisphere flights doubles. 
  • Our SOFIA User community of investigators and authors is 2,138 strong and growing. 
  • Virtual science workshops and other community engagement activities have increased our wider SOFIA community size by 42% this past year alone. 
  • SOFIA has increased grant support for observers and archival users to better support users.
  • Cycle 10 introduces new opportunities for time domain studies in the far-IR.

Contributing to multi-messenger science, SOFIA offers joint observing programs with GBT and IRTF, pilot programs with HST, and joint science talks and conferences with ALMA. We have several Cycle 9 programs that directly support JWST Cycle 1 observations and expect more in Cycle 10. SOFIA provides critical far-IR observations of targets under investigation with JWST. Additionally, SOFIA can offer mid-IR spectroscopic opportunities for select JWST targets with higher spectral resolving power, as well as measurements of bright sources that saturate JWST’s instruments. This coming year, SOFIA maintains our energetic community engagement activities, adding a virtual far-IR school for students and early career scientists and an in-person meeting. 

Preparations are in an advanced stage to present SOFIA to the 2022 Senior Review panel, which evaluates the progress of operating missions since their last review, their plans for the future, and their scientific merit with respect to NASA and Astro2020 Decadal report priorities. SOFIA is the first human crewed observatory to enter Senior Review. While the human crewed aspect may limit total hours that science observations can be conducted, there are advantages to this suborbital platform. Like HST, SOFIA can repair and update its instruments technologically but does so more cost effectively and with a faster delivery schedule. SOFIA’s instrument roadmap outlines a science-driven plan for new instruments that can increase scientific performance by a factor of ten, opening up new science discovery space. Cost savings from efficiencies within SOFIA are returned to the community to support this important instrument development program.

Suborbital programs such as SOFIA are essential to further science and technology to be used in space missions. The balloon program, which is another suborbital portfolio, focuses on PI-driven far-IR observations with very limited science hours, no fully supported community guest observer calls, and small publication rates. However, far-IR technology developed in the innovative and experimental balloon platforms can be applied in a more capable instrument on SOFIA which has larger aperture, power, mass, and volume envelopes. SOFIA offers the only reliable and repeatable suborbital platform for guest observers and instrument maturation, supporting a scientifically diverse opportunity for the astronomical community. Moreover, SOFIA is the only flagship mission capable of far-IR observations that can follow up on discoveries made with Herschel and (cold) Spitzer, both of which had limited lifetimes.

We are grateful for your letters of support (e.g., this letter from the IRSTIG), as we enter our final preparations for Senior Review. We are most delighted by your published papers which are pouring in steadily – keep them coming, every paper counts! Papers are the strongest way to show your support. Thanks.

Happy Holidays!

Margaret Meixner
Director of SOFIA Science Mission Operations