Radio Science

PDS Management CouncilNode Report

2 April 2009

Dick SimpsonStanford University

Topics to be Discussed

•Scope of Radio Science

•Role of Radio Science within PDS

•Immediate Future/Recent Developments

Scope of Radio Science

planetary surface properties and mappingatmospheric/ionospheric structure, dynamicsring structure, dynamics, particle properties

interplanetary plasma, solar coronaspacecraft navigation, ephemeris development

mass estimation, gravity models, interior structuresurface/atmosphere volatile exchange

radio emissionplate tectonics, Earth rotationgravitational waves, relativity

telecommunication, data managementsignal processing, radar imaging

Use of propagating electromagnetic waves to explore, measure, andunderstand the universe (more narrowly, the solar system)

Figure courtesy Sami Asmar (RSSG)

RS Role within PDS

RADAR IMAGING

TRACKINGNAVIGATION

ASTROPHYSICS

IONOSPHERES

OPACITY PROFILES

ATMOSPHERES

STANDARDS

SURFACESINTERIORS

MASS ESTIMATES

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

Advice to Users/Missions

through Discipline NodesCommentary on the Enterprise

Maybe the skyis falling ...

ActivitiesRecent Past and Immediate Future

Data Set

Contacts Task

MRO GEO/RSSG Review updated archive design and products (new data type added)

MESS GEO/APL Review updated archive design and products (new data type and documentation added; pre-orbit confirmation)

ROS SBN Review updated archive design (tentative)

CASMESS

ESAUser

Assist investigator working with solar conjunction dataAssist researcher seeking data

ODY Stanford Continue archiving RS data

TBD Stanford Resume restorations (Voyager, Viking, Magellan, Apollo)

PDS MC/TG Continue policy, standards support; PDS 2010 as feasible)

n/a GSFC/HQ Negotiate new management relationship

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 DataThe 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