Vibration Analysis of the Advanced Stirling Radioisotope Generators Tom Sutliff (for June Zakrajsek) Doug Mehoke NASA Apppplied Ph ysics Laborator y Small Body Assessment Group July 11, 2012 ASRG Major Components and Interfaces Advance d Stir ling RdiitRadioisotope Genera tor (ASRG) SBAG Meeting July 11, 2012 2 ASRG Component Status • ASCs (convertors) E3s - first build of flight configuration – The flight ASCs have completed their FDR (CDR) closeout, moving toward production (long leads were already authorized) – The first of the final engineering (E3) series ASCs are completed and are in checkout testing • ACU (controller) final engineering (EDU3) box is finishing its testing ASC ACUCU 3 ASRG Technical/Schedule Plans • System Performance (mass, power, environments) still meets Discovery-12 commitments • Component FDRs (CDRs) in process – Generator Housing passed - Aug 2011 – Convertors passed - Feb 2012 – Controller review passed - May 2012 • System FDR closeout - mid-July 2012 • QU fabrication complete - Oct 2013 – Two flight units to follow to DOE/Idaho National Lab • Two fueled flight units to KSC ~Aug 2015 • Typ ica lflihtdl flight deve lopmen t sc hdlhedule marg in in han d The ASRG development flow supports a January 2016 launch target 4 Hall System Development Milestone Status Projected Test Date HIVHAC thruster Performance GRC Completed December 2011 Acceptance Test (PAT) CPE Power Processing Unit Vacuum GRC Completed April 2012 Extended Operation Test (>500 hours) HIVHAC thruster Environmental GRC Completed May 2012 (()Vibration) Test Xenon Feed System Delivery GRC Completed June 2012 BPT‐4000 High‐voltage Wear Test JPL Scheduled September‐ October 2012 HIVHAC thruster Environmental JPL Scheduled November 2012 (Thermal Vacuum) Test HIVHAC Long Duration Wear Test GRC Scheduled December 2012 Initiation Hall Performance Verification Tests GRC Being FY13Q1/2 (in High Vacuum Test Chamber) Planned Hall Propulsion System Integration GRC Being FY15 Test Initiation Planned SBAG Meeting July 11, 2012 Discovery Technology Development for Whipple: Reaching into the Outer Solar System PI: Charles Alcock,,py Smithsonian Astrophysical Observatory July 11, 2012 •Less than 1 millionth of the volume of the solar system has been explored * •Objects beyond the Kuiper Belt are too distant to visit, & too faint to observe directly •This region will only be studied via the occultations of background stars •One candidate occultation event has been attributed to a small KBO *Schlichting et al 2009, Nature, 462, 895. The Whipple mission: Technology development plan is to build an end‐to‐end •Will monitor ~10,000 (20,000) stars @ 40Hz (20 Hz) to simulator of the Whipple photometer, including: search for occultations by small objects (0.5 km KBOs; 5 •Programmable LEDs to simulate stars undergoing occultation km Oort Cloud) between 40 AU and >10,000 AU events [done] •Observed fields widely distributed over sky •Simple lenses to represent Whipple optics [done] •Stars imaged by a 77 cm Schmidt‐Cassegrain optic onto •Teledyne CMOS detector with SIDECAR ASIC [in progress] a hybrid CMOS focal plane; field‐of view 6o×6o •Real‐time “on‐board” photometry and event recognition on •Photometry and light curve analysis (event search) FPGA board [in progress] performed on board because of high data rate •“Te lemetry to ground”/full end‐to‐end testing [Dec 2012] •Only candidate event data sent to ground for detailed •Version 1.0 of ground system analysis pipeline. [2013] analysis PriME is a Proposed NASA Discovery Mission The proposal was selected in the last round of Discovery in Category 3, which provides technology funding for the mass spectrometer. It is not an actual accepted mission (yet!) What is the range of chemical and isotopic diversity in the comet populti?lation? Is there any correlation between che mica l co mpos iti on an d nucleus physical properties? PriME will provide a detailed inventory of scores, if not hundreds, of volatile species. Motivation: Cryo-trapping Requirements for 30% precision 36Ar / 84Kr 1E+6 • Sample concentration >36 years – Even though MBTOF is over 1000 1E+5 analysis time times more sensitive than Cassini INMS (10x from ion source strength without and 100x from better duty cycle), concentration our) 1E+4 calculations show that it would take hh thirty six years to reach the desired precision through direct sampling. 1E+3 – Cryo-trapping increases the signal and reduces the reqqyuired analysis intervals nalysis time ( aa for the most difficult components – the 1E+2 noble gases - to ~40 hours. Total – The cryo-trapping also increases ion -6 source pressures to ~10 Torr, well 1E+1 abthtiitdhilbove the anticipated chemical background seen on Cassini INMS, improving signal to noise for the 1E+0 analysis. 1E+0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 Sample concentration factor Cryo-trap Implementation • Cryo-trapping Cold collimator – Long established vacuum technique excludes spacecraft – Freeze gas onto adsorber at 77K atmosphere – Uses space heritage Ricor cooler (used on CRISM, VIRTIS (Venus Express, Rosetta), VIR (Dawn), and Messenger Sleeve valve • Operation cycle rotttates to – Cool adsorber to 77K select inlet or – Open adsorber to gas MBTOF – Trap for required time – Open adsorber to MBTOF – Warm to release gas • Near term development plan – SwRI is in the midst of a very similar development program for space applications of cryo-trapping that will result in a TRL for the proposed cryo-trap before the due date of the MBC Discovery proposal. – The cryo-trap has been shown in the previous viewgraph to be necessary to Ricor reach the sensitivity levels for the noble cooler gas requirements from the RFI . cold-finger Adsorber head cooled to 77K MBTOF A Next Generation Mass Spectromete for Probing Solar System Formation.