The United States Air Force Manual Space Navigation Experiment on Skylab (DOD/NASA Skylab Experiment T-002)
Abstract
The purpose of this report is to present the results of the USAF manual space navigation experiment flown on SKYLAB in 1973. The manual space navigation problem is defined as "onboard orbit determination independent of primary system sensors, computers, and electrical power." The word "manual" implies obtaining input data with hand-held optical instruments. USAF objectives were twofold: to define the quality of manual navigation data typical of low earth orbit, and to test a data processing scheme developed for the Air Force in the late sixties. Two hand-held instruments were used: a space sextant and a space stadimeter. The sextant was used to measure star-horizon angles and the stadimeter was used to measure altitude. Analysis of data obtained with these instruments indicates that no sharply defined horizon reference exists for low altitude manual space navigation. Mean horizon height is different for each instrument and must be treated as an uncertain bias in the data. Star-horizon data is roughly twice as precise as altitude data. The top of the airglow is the best reference for star-horizon measurements. Characteristics of manual space navigation data invalidate the assumptions involved in the simple data processing scheme developed for the Air Force. Current minicomputer technology makes it possible to mechanize more sophisticated techniques within reasonable mass and volume limits. Least-squares differential correction (LSDC) can be used to obtain navigation solutions accurate to within 7 km and 7 mps. Altitude data is not required. The authors recommend the development of a new hand-held sextant which incorporates a minicomputer for automatic LSDC processing. Critical to improved performance is increased measurement precision.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1975
- Accession Number
- AD1063268
Entities
People
- Jackson Jr R. Ferguson
- Richard C. Walsh
Organizations
- United States Air Force