T he Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint program between NASA and the German Space Agency, or DLR . The agreement is that NASA provides the platform for the observatory, a highly modified 747-SP, while DLR provides a 2.5-meter telescope that is capable of operating from visible up to millimeter wavelengths. The airplane modifications and the telescope assembly development were both extremely difficult, one-of-a-kind technical challenges. I say “were” because as of early February, all of the physical modifications to the aircraft were complete, and the DLR-provided telescope was fully integrated into the airplane and had passed two initial optical test periods. SOFIA is now within months of its first flight test.

Almost simultaneous with the successful completion of the physical modifications to SOFIA came the news that SOFIA had been zeroed from NASA’s 2007 budget request, and that NASA had decided to hold what was termed by NASA headquarters as a “close-out” review — one where the decision was basically how to dispose of the parts and where to mothball the airplane after its maiden flight.

The initially announced rationale for close-out was that SOFIA schedule slips created little to no overlap with Spitzer. Additionally, NASA noted that SOFIA operations would begin around the time that European Space Agency’s far-infrared/sub millimeter space mission, Herschel, would be launched, and that this schedule interface would further significantly reduce the scientific value of SOFIA.

A bit of history is relevant here. SOFIA was first recommended, and highly so, in the National Academy Astronomy Decadal Survey of the 1990s and again in the first Decadal Survey of the new millennium. Nothing in those recommendations mentioned a critical relationship between SOFIA and Spitzer. Indeed, SOFIA was envisioned to be like its predecessor, the Kuiper Airborne Observatory. It would operate for up to 20 years, with a system that made possible the modification and upgrade of instruments incorporating up-to-date technology.

This latter feature distinguishes SOFIA from all NASA missions with the possible exception of Hubble. One nice feature of SOFIA is that its instruments cost about a tenth that of an Hubble Space Telescope instrument, and no astronauts are needed to change them. It appears to be the case that there will be less overlap between SOFIA and Spitzer than one might hope, but SOFIA’s operational schedule will now overlap fully with James Webb Space Telescope.

In the fall of 2004, NASA headquarters commissioned a series of three independent reviews of SOFIA. One of these reviews, the Independent Science Operations Review , concluded the following:

“There is every expectation that SOFIA will have the type of fundamental scientific impact that is usually associated with Great Observatories well into the post-Spitzer, post-Herschel era, provided proper investments are made in future state-of-the-art instruments. In comparing the operations costs, it is important to bear in mind that the SOFIA paradigm is different from the Great Observatory paradigm, particularly that for the non-serviceable missions Spitzer and Chandra. For those Great Observatories, the paradigm is a fixed instrument payload and a General Observer/User Support philosophy based on continued use of that payload over the life of the mission. In contrast, access to the instrumentation for upgrades, incorporation of new instrumentation, and operational nimbleness are integral to the scientific success of SOFIA. The costs of operating the aircraft and of the instrument technology/upgrade program have to be viewed from this perspective. When we do this, we feel that the SOFIA operations approach, the balance of the program [even if modified as suggested in 2. above], and the costs are appropriate. Note that in 2005 dollars, the operations cost proposed for SOFIA in the presentation is about 80 percent that of Chandra, 65 percent that of Spitzer, and less than 50 percent that of Hubble.”

While the Independent Science Operations Review noted the desirability of operational overlap between SOFIA and Spitzer, nowhere was that taken to be the measure of SOFIA’s scientific value as has been implied recently. The Independent Science Operations Review findings quoted above served to validate the timelessness of the recommendations put forward a decade before by the Astronomy Survey of the 1990s.

Mr. Howard, the current acting director of NASA’s astrophysics division, remarked in formal comments at the opening ceremonies of the German SOFIA Science Institute at the University of Stuttgart roughly one year ago, that: “The other point that I want to make is that we look at SOFIA as being our Airborne Great Observatory. The science that will come out of SOFIA is world class, is in the class of the Great Observatories. And so, SOFIA will take its place as the first Airborne Great Observatory along with its forerunners: Hubble, Chandra, Spitzer and the Compton Germany Ray Observatory.”

Indeed, at a meeting of the joint international SOFIA management team that was meeting in Stuttgart in conjunction with the German SOFIA Institute ceremonies, Mr. Howard noted that the Independent Science Operations Review statement quoted above justifies roughly $400 million in operational funding for SOFIA.

It would seem that the science of SOFIA is not really an issue. This leads me to the things that “go bump in the night.”

If scientific value is not the reason for zeroing out SOFIA, that should leave cost and schedule as the possible reasons for taking such action. There is no doubt that the cost for SOFIA is greater than originally thought, nor is there any doubt that it is well behind schedule. But a closer look indicates that this is due mainly to changes in the program throughout its lifetime.

The original contract was for $167 million in December of 1996. This is just for the contractor team and does not include funds for NASA involvement, which was intended originally to be minimal . The current contractor costs are $337 million , which is $170 million more than the original contract. However, the bulk of this increase arises from requirement changes and contract modifications introduced by NASA during the development phase. Some of these changes arose because of the events of Sept. 11, 2001, and the Space Shuttle Columbia accident.

One of the changes that NASA directed was to put more control of the development under NASA than was envisioned in the original contract. That has led to a substantial increase in civil service manpower working on the project, and they were not part of the original contract concept. With full-cost accounting now in play, this has had a corresponding effect on the overall budget.

Finally, the budget for SOFIA has waxed and waned since 2001. This instability, coupled with the unanticipated costs from new NASA requirements, has caused a corresponding schedule slip. Even as these events have caused cost increase and schedule slip, there were no signs until the most recent budget release that NASA headquarters did not understand and accept the underlying causes for acceptable cost increases on SOFIA.

The total NASA expenditure to date is about $500 million, and Germany has expended about $100 million , and SOFIA is nearly to first flight. The cost to complete the SOFIA flight and mission performance testing would be comparable to the cost to close the program down.

As for technical challenges remaining, the revolutionary SOFIA cavity door system is the only low-classification technical risk remaining on the program. To mitigate this risk at open-door flight test, the contractor, NASA, and independent industry engineering groups have performed extensive additional wind tunnel and engineering analyses over a six-year period. The results of these tests are that SOFIA’s door system has received a clean technical bill of health from all groups. This cavity door system analysis effort added approximately $40 million and a minimum of three years to the original SOFIA contract, but the results of these new requirements provide a safe and operable observatory system.

The 747-SP that will carry the remarkable 25-ton telescope provided by DLR was originally a part of the PanAm fleet. This particular aircraft was the Clipper Lindbergh and was christened by Mrs. Lindbergh. It would be good to see the spirit of exploration and inspiration that Mr. Lindbergh brought to America all those years ago, carried forward by SOFIA as it makes discoveries that will rival those of its sister “Great Observatories.”

David C. Black is president of the Universities Space Research Association.