1. ICON Student Experiment John Westerhoff, Gary Swenson University of Illinois at Urbana- Champaign

2. Overview Student Collaboration Phase A Requirements and Evaluation Science Objectives Hardware Implementation ICON Mission Requirements Phase A Tasks

3. Phase A Requirements for the SC

5. Phase A Requirements – SC Funding may be outside PI-Managed Mission cost up to SC incentive: 1% of PI-Managed Mission Cost Cap ($200M) CSR Section I: Student Collaboration – 5 page limit for SC – Identify SC as an E/PO element – Detail development schedule of SC, including decision points for determining SC readiness for flight – Demonstrate how SC can be incorporated into baseline mission on nonimpact basis – Demonstrate that SC is clearly separable for rest of proposed effort – Plan for mentoring and oversight of students – Identify funding set aside for SC

6. CSR Evaluation of SC Along with E/PO, SDB, 5% weighting SC Merit factors: – Science/engineering alignment of proposed SC investigation – Implementation merit of SC based on technical, management, and cost feasibility, including cost risk – Educational merit of SC Quality, scope, realism, appropriateness of educational objectives Continuity: SC involves students interested in NASA and engages them in the next level of involvement in E/PO Evaluation: plan and methods Diversity (Program Balance Factor): engaging underrepresented groups

7. Phase A Tasks Science requirements and instrument simulation SC development schedule Environmental testing of PMT – Vacuum testing – Vibration testing Develop conformal coating procedure for PMT Evaluate alternative PMT for NIR channels: Hamamatsu H10770PA-50 – Improves S/N 150% – Adds ~0.4kg, 1.6W to budgets, may require larger volume (11x19x23cm)

8. Science Objectives Investigate Atmospheric Gravity Waves (GW) via remote sensing of mesosphere, including high frequency waves (λ x > 30 km). Provide global measurement context for small to medium scale (λ x > 30 km) LWBs (large waves or bores) Observe large amplitude (A > 10%) LWBs and determine their intrinsic properties (A, λ x, λ z ) Observe packets of small amplitude (A > 1%) waves and determine their intrinsic properties Categorize horizontal and vertical wavelengths into small, medium, large scale Determine rotational temperature perturbations (T’/T) of waves

9. Measurement Approach Observe O 2 (0-0) rotational emission and O 2 Herzberg emission (nadir viewing) Brightness perturbation measurement (I’/I) provides wave amplitudes Ratio of O 2 P and R branch provides rotational temperature perturbations (T’/T) Phase differences between (I’/I) and (T’/T), and between O 2 (0-0) and Herzberg bands, provide vertical wavelength measurements Cross-track measurements of (0-0) atmospheric band provides azimuthal wave orientation and horizontal wavelengths

10. Science Requirements Science requirementMeasurementSensor channel S/N Required Margin Determine amplitude of LWB (A>10%) I’/IO 2 A, H101050% Categorize λ x, λ z of LWBs as small, med, large scale Vertical and horizontal phase, I’/I-T’/T ratio O 2 A, H10210% Determine LWB wave orientation within 30° 4ch-horizontal phase 4-ch O 2 A12TBD Determine rotational temperature (T’/T) of LWBs I’/I, P/R branch ratio O 2 A, H10TBD Secondary science requirement to conduct these same measurements for small amplitude (A>1%) wave packets (5+ waves)

11. Image taken from ATLAS-1 mission by the AEPI experiment, March 24, 1992. The image was taken with an O 2 Atmospheric (0,0) band filter at 762.0 nm, similar to that proposed for the ICON Student Experiment (Mende et al., 1994)

12. Quasi-monochromatic (left) and chaos (right)

14. O 2 Herzberg, I’ 95.5 km O 2 A, I’ 92.5 km HWL VWL phase difference observed GW phase fronts and wave phase information versus altitude GW phase fronts

16. TOMEX Potential Energy vs. Altitude, Four Nights Data

17. Hardware Implementation: Sensors Photomultiplier tubes: 7 Hamamatsu H10862 PMTs 1nm filters centered at 760.5, 763.5nm for (0-0) band P and R branch 2nm filter centered at 770nm (background channel) Bandpass filter from 255-292nm to measure O 2 Hertzberg band, with notch at 280nm to block Mg emissions 4 PMTs used on (0-0) R branch with FOVs across 8° perpendicular to orbit plane: obtains cross-track measurements

18. Coarse 2D imager using PMTs 4 PMT modules Optics assembly, with filter and lens Fiber optic coupling 4 viewing directions, 8 o full angle, perpendicular to orbit plane Coarse 2D imager using 4- channel PMT Fiber coupling to focal plane Use R branch of (0-0) band View angles oriented perpendicular to orbit plane (-2.25°, 0°, 2.25°, 4.5° from nadir) Adds ~250g and 0.22W power, 6.9 Mbit/day data

19. O 2 emission and P-R branch filters

20. A 1% uncertainty in R yields ~ 1% uncertainty in T

21. Signal Analysis: PMTs Center wavelength (nm)760.5763.5770273.5 SensorH10682-01 H10682-110 Source brightness (Rayleigh)6000 40+600 Subject distance (km)460 Lens diameter (mm)38 75 Aperture diameter (mm)1.0 2.0 Dark count @ 25°C (Hz)600 50 Effective band transmission (%)2013n/a15 Quantum efficiency (%)1.6 21 Footprint width (km)12.1 12.3 Integration time (sec)1.0 S/N ratio (for 1.0 sec IT)9172n/a189

22. PMT Assembly Schematic (38mm) with heater

23. PMT Assembly Schematic (75mm)

24. Solid model of student experiment Volume: 11x19x20cm O 2 Herzberg channel 75mm aperture O 2 atmospheric channels with temperature regulated filters 38mm apertures 4-pixel O 2 A channel assembly with fiber coupling C&DH and Power boards O 2 A background channel 38mm aperture

25. Test PMT Assembly

26. Mass Budget Data sourceMass (g) H10682 PMT modules525 PMT optics assemblies840 C&DH board125 Power board75 Engineering sensors110 Structural and mounting hardware650 Integration hardware and wiring300 Total Mass2625 g

27. Power Budget ComponentPower (W) QtyDuty cycle Avg Power (W) H10682 PMT0.270.370.52 38mm filter heater0.421.000.80 C&DH board (day)0.310.630.19 C&DH board (night)1.010.37 Power load1.88 W DC-DC converter efficiency80% Total power2.35 W

28. Datalink Budget Data sourceData rate (Mbit/day) PMT Sensors9.97 Engineering data0.13 Data rate10.1 Mbit/day Overhead10% Total data rate11.1 Mbit/day

29. SC Subsystem Cost (Illinois) Project PhaseCost Phase A$13,146 Phase B$235,798 Phase C/D$648,836 Phase E$348,141 Phase F$28,480 Total subsystem cost$1,274,400

30. SC Requirements on ICON Mission Bottom plate mounting for SC instruments, nadir pointing 19x11cm bottom plate footprint requirement Power and data connector to ICD Spacecraft provided command and data interface – Command signals from spacecraft – Data upload to spacecraft – Time synchronization SC mission data analysis requires access to ICON mission data (position, attitude of spacecraft)

31. SC Requirements on ICON Mission Bottom plate mounting for SC instruments, nadir pointing 19x11cm bottom plate footprint requirement Power and data connector to ICD Spacecraft provided command and data interface – Command signals from spacecraft – Data upload to spacecraft – Time synchronization SC mission data analysis requires access to ICON mission data (position, attitude of spacecraft)

32. Backup Slides

33. λ z measurement Vertical wavelength measurement (λ z ) from phase difference between (0-0) and Herzberg bands Best difference signal at zero phase in one of the channels: Error in brightness measurement: λ z calculation: Error in λ z calculation:

34. λ z error vs. I’/I for λ z =20,30km

35. O 2 A band

36. Proposal Requirements – SC SC must depend on baseline mission being implemented SC must not impact baseline mission in the event that: – SC is not funded; – SC fails during flight operations; – or SC encounters technical, schedule, or cost problems in development SC must include plans for mentoring and oversight of students SC may have the potential to add value to science or engineering of the baseline mission