Radio Science PDS Management Council Node Report 2 April 2009 Dick Simpson Stanford University
Topics to be Discussed • Scope of Radio Science • Role of Radio Science within PDS • Immediate Future/Recent Developments
Scope of Radio Science Use of propagating electromagnetic waves to explore, measure, and understand the universe (more narrowly, the solar system) planetary surface properties and mapping atmospheric/ionospheric structure, dynamics ring structure, dynamics, particle properties interplanetary plasma, solar corona spacecraft navigation, ephemeris development mass estimation, gravity models, interior structure surface/atmosphere volatile exchange radio emission plate tectonics, Earth rotation gravitational waves, relativity telecommunication, data management signal processing, radar imaging Figure courtesy Sami Asmar (RSSG)
RS Role within PDS STANDARDS ATMOSPHERES SURFACES INTERIORS RADAR IMAGING MASS ESTIMATES TRACKING NAVIGATION ASTROPHYSICS OPACITY PROFILES IONOSPHERES
What is PDS/RS?Personnel and Resources • 3+ People at Stanford • PI Len Tyler (~1% FTE) • Manager Dick Simpson (~15% FTE) • System Software Analyst Ray Jackson (~5% FTE) • Administrative Support • Several Networked Computers and a Telephone • None provided by PDS • Funded mostly by NASA/MEX • Library of data, software, and documentation • $50-60K/year
Role of Radio Science within PDS Maybe the sky is falling ... Advice to Users/Missions through Discipline Nodes Commentary on the Enterprise
ActivitiesRecent Past and Immediate Future
Backup
PDS/RS Functions • Advise providers on design of new RS data sets • Review design of new data sets (DN support) • Assist users trying to locate RS data • Assist users with interpretation of RS data • Support PDS MC, Tech Group, and Working Groups • Collect and archive RS data from Mars Odyssey (ODY)
Why PDS/RS? Large, complex, raw data sets need to be archived so that their utility transcends conventional mission and program boundaries RS data sources/products/objectives are common across missions Most RS data are created within NASA’s DSN, which evolves on decadal time scales For non-DSN data, cooperative agreements are being negotiated which will allow translation (e.g., to simplify joint DSN/ESA spacecraft support) Ability to exploit data often lags measurement precision Processing power expands Old measurements provide longer time base PDS is ideally positioned to fill this role, if given sufficient resources, and operations organizations cooperate
Large, Complex Sets of Precise Raw Binary Data The pre-MGS ‘standard’ gravity model for Mars was generated by Balmino et al. (1982) Derived from Mariner 9 and Viking Orbiter radio tracking data, it was of degree and order 18.
Need to Be Archived > 10 Years Using exactly the same data as Balmino, Smith et al. (1993) generated a 50x50 model. Konopliv and Sjogren (1995) followed. Smith and Sjogren were unable to find the original data in the U.S., and succeeded in theirpre-MGS analyses only after (re)acquiring the data from France. Main story is pre-PDS; but Viking data are now in the Stanford (PDS/RS) restoration queue.
Contemporary Activities(with similar issues) • Margot sought to create pre-MESSENGER Mercury gravity model • if they exist, Mariner 10 files are in archaic DSN format(s) at JPL • PDS/RS assisted in search, but practical result is negative • MRO Gravity Team using ODY data to refine: • high-altitude atmospheric (drag) model (Mazarico) • estimates of volatile exchange between polar surface and atmosphere (Zuber) PDS/RS playing unexpected positive role in newly developing science • Periodic requests for Galileo Orbiter data • raw data delivered to PDS, but held in safe status (not PDS compliant; who fixes?) • reduced data never delivered (problem not limited to RS; who processes?)
Why Stanford? • Stanford has been doing Radio Science for more than 50 years • Participated in Mariner 2 and many NASA missions since • Currently active in MEX, VEX, and NH (and ODY, through PDS) • Represented Radio Science in PSASS in 1980’s • Served as PDS Radio Science Advisor since early 1990’s • Pioneered modern RS archiving with MGS • Developed design and labeling software used in other archives
