A COMPARISON OF THEORY AND OBSERVATION OF THE ECHO I SATELLITE
Abstract
Observations of the Echo I balloon satellite were compared with a theory including the following perturbing effects: (1) solar radiation pressure; (2) lunar and solar gravitation; (3) second, third, and fourth harmonics of the earth's gravitational potential; and (4) atmospheric drag. With a set of orbital elements at the 26th day of the lifetime of the satellite, it was possible to match the observational data to 180 days with root mean square residuals. No differential correction was applied. Values of atmospheric density between 1500 and 930 km, assuming neutral drag effects only, have been inferred from the orbital data. The connection between solar activity and drag is also examined. As the Echo I perigee height continues to oscillate between 900 and 1500 km, more valuable orbital data will be obtained and atmospheric properties will be deduced. Further refinements in the mathematical model, especially in a timedependent model atmosphere, should bring a substantial reduction in the residuals of the observations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1961
- Accession Number
- AD0268749
Entities
People
- R.w. Bryant
Organizations
- National Aeronautics and Space Administration