Insider's Look at Designing Orbiting Satellite Experiment

Earth orbiting satellites have been around for many years now and have become so commonplace that launches usually don't even make the news. The Explorer-I satellite was the first US satellite put in orbit and was launched January 31, 1958 from Cape Canaveral Florida, now known as Cape Kennedy. The experiment payload was designed and built by Dr. James Van Allen of the State University of Iowa and was a key part of the International Geophysical Year 1957-1958 program to learn more about the geophysics of the earth's atmosphere.

Since those early days a wide range of satellites have been designed and launched for purposes of improving weather forecasting, communications, sensitive military programs and monitoring, and even oil prospecting. In addition there have been satellites devoted entirely to research which most cases involve experiments designed by either government labs or academic institutions. For purposes of simplicity this article will deal with research satellites, namely those hosting academic institution experiments.

From the standpoint of a university researcher the notice of an upcoming satellite mission will take the form of a RFP or request for proposal. In the RFP the purpose and specific goals of the mission are outlined along with parameters such as the orbit type, the length of the mission, the space and volume requirements, the project timeline and the content requirements for submitting a proposal.

If you are a researcher and have expertise and an interest in providing an experiment for an upcoming satellite you set about gathering the materials required for the RFP submission. This includes the concept for the experiment that you want to conduct, and the design of the instrument you propose to build and fly. The amount of money you will ask for to fund the staff and materials, travel and data analysis you anticipate requiring. This is somewhat similar to a contractor bidding on a construction job thus a significant amount of time and effort are required to put together your proposal. In addition the contracts are awarded taking into consideration your track record and accomplishments as a scientist. Most RFP's are issued by NASA, the National Aeronautics and Space Administration.

If you are fortunate and your proposal gets chosen you are given project milestones and dates you must meet to secure your position when the satellite is launched. In most cases a satellite program will have a team of researchers associated with it and periodic team meetings will be held to keep everyone abreast of changing project plans, parameters, and timelines. It is important to attend these meetings not only to keep current on changes but also to establish contacts with other university researchers with experiments on the same satellite. Quite often you will eventually collaborate with them on scientific papers thus it is important to nurture these relationships early in the project.

Back in the lab you need to hire and establish you're own project team of engineers, programmers, scientists, technicians and other specialists you will require to complete the experimental package. Typically a principal researcher will have a project manager to handle the day to day decisions. Once the concept of the experimental measuring device is solidified a one of a kind breadboard is made to test the validity of the concept. The breadboard is a simplified version of the final experiment and usually undergoes many changes, as the design is refined. Not only the mechanical part of the package must be developed but also the electronic part. These are brought together in the prototype stage that more closely represents the final experiment in terms of configuration.
After months of testing and refinement the design is frozen and a formal set of drawings is updated to reflect the parts and configuration. During this period periodic reports are given to NASA to reflect the progress as well as the financial expenditures.

Typically two final versions of the experimental package are made, one for flight and one for a backup. They are both considered flight ready and the backup will be brought into service should there be any last minute problems in the primary unit. As part of the testing of any satellite experiment the researcher must devote a significant amount of time to calibrating the instrument so that the raw data received on the ground may be converted into relevant geophysical parameters. With a new type of instrument this calibration equipment must often be specially designed and built for the package being calibrated.

In parallel with the scientist's efforts, the main satellite contractor will be designing and building the satellite that your and other experiments will be part of. This is an exacting job since many experiments are literally riding on the job being done right and the satellite performing flawlessly. There are numerous items such as telemetry communications, power for the experiments, guidance systems, thermal controls, booster rockets and interfaces with the main launch rocket that must be taken care of without an error.

During the latter stages of construction the individual experiments undergo environmental testing where they are subjected to thermal and vibrational testing representative of a rocket launch and years in orbit. Then the experiments are integrated into the satellite where the satellite plus the experiments undergo even more rigorous testing.

After months of exhaustive testing launch day arrives and, with proper weather conditions, takes place. The excitement of being at the launch range watching the rocket carrying your experiment into orbit is hard to describe in terms of excitement. Once in orbit a period of time is allowed for any trapped atmosphere to leak out of the experiments.

Once done the experiments are individually turned on for that moment of truth when you find out if all your hard work will generate the data which, after all, was the goal of the endeavor. With the analysis of this data will come papers and talks and most importantly a better understanding of the earth and it's atmosphere geophysical properties and functions.