used was capable of exa mining area s as small a s 10 µm, making it feasibl e to examine micro scopic  particl es, fibers an d small  quantitie s of residues. FTIR is also u seful for i dentifying lu bricant degradatio n  products. 

SEM (Scanni ng Electron Microsco pe) equip ped wit h an EDS (Energy Dispersive Spe ctroscopy) sy stem  is  used to ide ntify elemental  com position of parti cles such as metallic d ebris found in bearings. It is al so  used to evaluate bea ring race, ball a nd se parator  damage a nd potential causes at hig h magnificatio n  levels. 

ESCA (Ele ctron Spe ctroscopy for Chemical An alysis) provides compo sitional  informatio n from the to p 5  nm of th e surface region. Preci se measurem ent of  photoele ctron bindin g energies provides the che mical  state of su rface atoms. Co mpositio nal informatio n below the uppermo st surfa ce layers was obtaine d by  ESCA in conj unctio n with a rgon io n sputtering. 

ICP/MS (Indu ctively Co upled Pla sma/M ass Spectrom etry) typically dete cts 65 different el ements at partsper-million (ppm) level s. For the FGS M/E investigation,  samples of the white residues from the clamp  rings, submitt ed in plastic snap-cap tubes, were di ssolved in 3 mL of 1% ultra-pure nitric a cid. Control  tubes were treated in the same manner along with the s ample residues  to chec k for back ground  contami natio n. The nitric acid solution s we re an alyzed u sing the semi -quantitat ive feature of a Hewlett   Packard Mo del 4500 ICP/MS (LIMS procedu re ICPM S_SEMIQUANT). Thi s method of  analysis i s  gene rally a ccepted to be accurate  to wit hin ± 20 to 30% of the a ctual analyte val ues. T he valu es obtaine d  from this an alysis were calculate d to ref lect the mi cro-grams of an alyte per gra m of sample as received  (ug/g, or p pm). 

OLM (Opti cal Light  Micro scopy) d etermines pa rticle  size di stributions. These were done  for the FGS  Servos by m anual  inspection of filter sampl es of the d ebris co llected  from  beari ng flush es using a  microsco pe equipp ed with a calib rated e yepiece reticule. 

A determi nation of the l ogistical require ments fo r the anom aly investigatio n should b e comp leted p rior to  commitment for execution of the pl an. This includes  facility requirement s (floor space, cl eanliness,   handli ng of h azardous material (safety requi rements)),  wipes, swabs, requi red chemi cals for cleaning or  flushin g debris, debris filters, gla ssware, pa cking materials, etc. Di sassembly to ols and Ground Su pport  Equipme nt (GSE) ne cessary for th e pre and  post inspection te sts, an d tea r down must be considered. In  sched uling th e task, indivi dual support perso nnel should be id entified by na me an d thei r availability  confirmed. Fi nally, a realist ic sched ule should be g enerated that lists the major ta sks to be pe rforme d with   allowan ce for minor deviati ons resulting from in-p rocess findi ngs. 

A final repo rt deadli ne sho uld also be id entified and closely tra cked. Since ofte n the ca use o f an anomaly   is not obviou s, it is import ant to sco ur through all of  the insp ectio n data whil e it is fresh a nd there is a n  oppo rtunity for more to be don e. Creation of the  final repo rt provide s a vehicle for systematically   analyzi ng the  data colle ctively to draw valid co nclusions and rep ort them to the intere sted pa rties. 

Below i s a gene ral summary outlin e for the steps necessa ry in planni ng a me chanism a nomaly  investigatio n. Althoug h some of th e items discu ssed here were  specific to th e HST  FGS  M/E anom aly  investigatio n, it can be u sed as a gui deline in many other in stances.  

Inspe ction Pl annin g Sum mary:  1. Determine th e most proba ble ca use for the anomaly.   a) Colle ct and review all rel evant desig n drawings.  b) Colle ct and review all rel evant test and flight data (if available ).  2. Determine th e desi red te sting pro gram prio r to tear d own of the un it.  a) Therm al and/ or vacu um en vironme nt required?  b) Motor curren t, voltage, torqu e tran sducer, velocit y, position a ccuracy, ope rational vib ration  (accel eromet er).  3. Surface, lubri cant, and p article an alysis tech niques require d to fully evaluate the unit to be inspecte d.  348