Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1088c Report Date: 09-May-96:16:08 Version: ********** Check-in Date: ********** 1.Proposal Title: SMALL SATELLITES IN THE URANIAN SYSTEM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/HSP Sub Category SATELLITES, RINGS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Robert C. Bless WISCONSIN, UNIVERSITY OF USA 608-262-1715 ------------------------------------------------------------------------------------ 7. Abstract The Voyager investigation of the Saturnian and Jovian ring systems revealed the intimate relationship between the structure of the rings and small satellites that orbit within or near the rings. The long term stability of ring systems is now thought to depend upon a chain of resonances that stabilizes the ring particle orbits by linking them--though resonances--to small, nearby moons, whose orbits in turn are stabilized through resonance links to the large, outer satellites. Establishing these connections depends upon obtaining precise orbits for the small satellites. To explain the structure of the Uranian system, most are expecting Voyager to discover several shepherd satellites within the ring system, and perhaps some in orbit between mirauda and the epsilon ring. These satellites would have magnitudes within the range +20-+25 and have proven--so far--to be undetectable from Earth. We propose a series of exposures with one of the cameras to establish the orbits of those satellites that have important connections with the ring dynamics. ------------------------------------------------------------------------------------ 8. Scientific Key Words: URANIAN SATELLITES, SATELLITE ORIBTS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 7.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HSP ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1088c PI: Robert C. Bless Proposal Title: SMALL SATELLITES IN THE URANIAN SYSTEM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Edward L. Robinson TEXAS, UNIVERSITY OF USA Robert C. Bless WISCONSIN, UNIVERSITY OF USA G. W. Van Citters NATIONAL SCIENCE FOUNDATION USA Joseph F. Dolan NASA, GODDARD SPACE FLIGHT USA CENTER Richard L. White SPACE TELESCOPE SCIENCE USA INSTITUTE James L. Elliot MASSACHUSETTS INSTITUTE OF USA TECHNOLOGY ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose a series of about 20 exposures (with the FOC or WFC/PC, as appropriate), each about 20 minutes to establish the orbits of several small satellites. Cycle 1, depending on observations by the wide-field camera team. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. These satellites are undetectabel with ground-based observations. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data will be reduced and anlyzed at MIT with the VAX 11-750 belonging to the planetary astronomy group. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). TBD ------------------------------------------------------------------------------------ 13. A series of exposures with one of the cameras would be used to establish precise orbits of any possible shepherd satellites of uranus that might be previously discovered by Voyager, HST, or ground-based observations. This program would be second epoch observations of the satellites, to be intiated after the wide-field camera team has completed their search for new satellites. The orbits of these satellites would have important connections with ring dynamics and long term stability of the ring system. ------------------------------------------------------------------------------------ 11. Address Information Name: ROBERT C. BLESS Category: PI Institution: UNIVERSITY OF WISCONSIN Address: DEPARTMENT OF ASTRONOMY City: MADISON State: WI Zip Code: 53706 Country: USA Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ Page 3 Name: JAMES L. ELLIOT Category: CON Institution: MASSACHUSETTS INSTITUTE OF TECHNO Address: BLDG. 54-422 City: CAMBRIDGE State: MA Zip Code: 02139 Country: USA Telephone: 617-253-6308 Telex (or e-mail): 921473 MIT CAM ------------------------------------------------------------------------------------ TARGET LIST c)Generic Targets ID = 1088c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 7 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Selection Criteria |Acqui|FLX| Flux data No | Name | Description | |Prblm|REF| | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS-SAT SMALL SATELLITE OF SMALL SATELLITE OF URANUS THAT HAS 1 V=23+/-3 URANUS RINGS ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1088c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS-SAT WFC IMAGE ALL-ND F606W 3 20M 20 1 1 CYCLE 2/1-3 ------------------------------------------------------------------------------------------------------------------------------------ 2 ^ ^ ^ ^ ^ 6 ^ ^ 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 ^ ^ ^ ^ ^ 12 ^ ^ 3 Comments: REPEAT EXP.1 3 TIMES, EXP.2 6 TIMES, EXP.3 12 TIMES. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1088c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ^ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HSP ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 7.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category SATELLITES, RINGS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 2/1-3; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W ^ ------------------------------------------------------------------------------------------------------------------------------------ Target Names URANUS-SAT ------------------------------------------------------------------------------------------------------------------------------------