NASA Spinoff

Hubble Systems Optimize Busy Hospital Schedules

Originating Technology/NASA Contribution

Beginning in 1985, a team of engineers at the Space Telescope Science Institute in Baltimore began developing software to manage various time-consuming tasks for the Hubble Space Telescope, launched in 1990. In the early phases of development, the complexity of scheduling different tasks became clear when the engineers realized Hubble’s power restrictions.

altWhen it first became operational, Hubble functioned under a variety of scheduling restraints. For example, in order to conserve energy, it could have only two scientific instruments operating at one time. This was further complicated by the length of time it took to move the instruments into position. Changing Hubble’s orientation to a new target, or slewing, was a slow process, moving only 90 degrees per hour. Likewise, the instruments themselves could take up to 24 hours to shift from standby to operative modes. Further complicating the schedule was the fact that certain tasks only operated during specific times, needing protection from (or exposure to) direct sunlight, or requiring specific angles, locations, or other conditions.

In order to compensate for these scheduling constraints, Hubble’s software team designed a knowledge-based system that worked around these scheduling conflicts using a variety of methods, such as backward and forward chaining—“If X is a near-infrared spectrometer, then X operates only when facing away from the Sun”—logical arguments used to design computer systems and software.


One of the team members who worked on Hubble, NASA computer scientist Don Rosenthal, helped develop the scheduling system, refining the algorithms in the programming and consequently increasing the telescope’s efficiency. After working on Hubble, Rosenthal acquired intellectual property rights to the scheduling technology. He then ran the artificial intelligence application group at Ames Research Center, where he developed programming for the Mars Exploration Rovers, the Pioneer spacecraft, and a system for human space flight.

Rosenthal went on to co-found Menlo Park, California’s Allocade Inc. in 2004, and is now chief technical officer of the company and chair of the board of directors. Using Rosenthal’s experience with Hubble’s software, Allocade created its On-Cue software suite, which optimizes ever-changing hospital schedules.

Product Outcome

On-Cue is a software solution that enables hospitals to reclaim their unused capacity. The system helps hospital departments handle dynamic rescheduling issues by allocating resources and managing disruptions in real time for inpatient and outpatient imaging procedures. In the past, staff made these time-consuming adjustments through numerous phone calls, whiteboards, handwritten notes, and faxes, which caused delays and frustration for both patients and staff.