(2) Th e individual align ment requi reme nts of the ro tating prisms re lative to each  other are loo se.   (3) L arge o pto-me chanical advantag e can be obtained d epending on th e wedge angle and in dex of  refraction of the individual prisms.      The BAM utilized ri sley pai rs that were already fabric ated for the Laser assem blies. The laser risl ey pai rs  where used to compl ete a static align ment of the  laser asse mblie s to the transmit path  and were adj usted  manually. Du e to the lo ng lead time s required fo r precision mat ched risley prism pairs, the  rapid BAM  developm ent (< 4 month s) coul d proba bly not have be en achieve d if spare mat ched risley p airs were not  available. 

Requirements  In orde r to n ot affect the GLAS sche dule, the deve lopment of th e BAM coul d have no im pact o n the  testing of the GLAS instru ment. All resource s req uired and re quirements d eveloped for the BAM must be   consistent wi th this no n-interfere nce re quire ment. T he BAM ha d to be devel oped utilizin g only “spa re”  resou rces of the spa cecraft and in strume nt. Based on the amo unt o f possible boresig ht misalig nment a nd  resou rces av ailable, the GLAS sci ence team, with  inputs from  the enginee ring team, d evelope d the  followin g requirements for the BAM:   Environme ntal and Resou rce Requirements   • Volume:     < 22.9 cm (9 ”) high, 17.8 cm (7”) wid e, 20.3 cm (8 ”) long   • Mass:      < 5 kg   • Powe r:     < 13.5 watts pea k, < 5 wat ts averag e  • Vibration:     Sine Burst: X  9.75 g, Y & Z ; 5 g  Random: ~ 7 GRMS X, Y, & Z axes  • Vibration:     Minimum Resonant Frequ ency >1 00 Hz     • Therm al:    -25°C to +40° C Survival, 0° C to 30° C Op eration  • Therm al:    < 30° C rise (30 mi nute op eration, 60 mi nutes to cool)  • Duty Cycle:     12 alignm ent seq uences (<50K motor re vs.)  • Contami natio n Levels:    100 A  • Magneti c Leakage:   < 10 milliga uss @ 30 cm  • EMI/EMC    Tested to Spacecraft Specification 

Optical Requirements  • Beam Adjust ment Range:     0.75 milliradians  • Beam stee ring precision:   30-50 micro radian s   • Wedge Physi cal Diamete r:  5.4 cm (2.1 26”) Existing Wedge Spa res  • Risley Rate (Linea r):   35 microradia ns/degree  • Clear Apertu re:    < 5.1 cm (2”) existing opti cs  • Laun ch Stabil ity:   < 10 mi croradians  • Wedge Angle :    0.127 ± .005 degree Existi ng We dge Sp ares  • Thickne ss:    0.55 cm (~0.217”) Existing  Wedg e Spares  • Optical Axis t o Bench:    6 cm (2.3 60”) As built   • Rotation al Ra te:    180°/min ute desi red, but n ot critical         (achieved 50°/minute, deemed acce ptable)  • Stability over observation:   < 20 mi croradians (4 arcsec.)   • Stability Observation to Observation:   < 20 microradians (4 arcsec.)   • Knowle dge of  Rotation:     0.6 ± 0.05 de gree  (by cou nting motor steps)  • Relative Rota tional Accura cy:   0.6 ± 0.05 de gree  (by cou nting motor steps)  • Prism to Pri sm Gap Tole rance:  Limited by Cl ear Ape rture   • Allowabl e ele ment Tilt:   <10 d egree s  • Allowabl e Assembly Tilt:   Rx and Ry = 5 degree s, Rz is Controll ed  • Allowabl e ele ment she ar:  Limited by Cl ear Ape rture  

Electri cal  BAM Electron ics (BAME) Requireme nts  49