were re quired. Additionall y, there are several coatin g processes that are p erformed o n the cerami c that  are sensitive to oil s, and gloves are required for ha ndling. Speci al drilli ng tool s are required for drilling  cerami c part s. Each body flap co st app roximately 14 m illion dolla rs to design, fabricate, test, and qualify  for spa ce flig ht. Therefo re, great precau tion wa s take n to pre clude damag e to the flight units. 

The schem e that ultimatel y proved  succe ssful for int egratio n of th e flap s and E MAs to th e vehicle was a  "top-do wn" in stallation. Th e EMAs a re dropped i nto place from open a ccess on the top of t he fuselag e.   Preci se positioning of the EMA axis wa s first p erformed t o CAD specs. Using a lase r system, a sp ecial  tool wa s emp loyed to mea sure and position the axis of the EMA rotating mo unt. The positi oning of the  EMA was based p urely on CAD layo ut dra wings.  While the EM A mounts were adj ustable, adjustm ents  were very difficult with the unit place du e to the weight and clo se clearances with primary structure. 

Once the EM As were  positioned as close as po ssible  to CAD spe cification s, an adjusted flap hinge axis  locatio n (relative to the  vehicle coordinate system) was derived based o n the measured EMA axis. Next,  physi cal po sitions o n the flap (co-lin ear with the hing e-line) were determin ed using laser tra cking. In orde r  to do this, an empiri cal flap  hinge axis was mea sured based on a ctual moveme nts of the flap hinge s. This  empiri cal flap  hinge axis was then p ositioned relative to  the desired  hinge-axis p ositioni ng on the vehicle.  

In order to accomm odate  variou s man ufacturi ng toleranc es an d tolerance build-up, the  flap attachme nt to  the vehicl e was adju stable  in six deg rees of freedom at both hinges. Final  alignment of the flap s was  made th rough a tri al and error combin ation of special flap p ositioning  tooling  and t emporary cl ampin g  procedures (Figures 12 &  13). Th e resulting relative angl e bet ween the fla p hinge -line and the EMA  hinge -line was less than a pproxim ately 0.05 deg ree. 

                  Figu re 12.  Flap Hinge (aft to left)                    Figure 13.  Flap Hinge Mounting (aft to right) 

Once the ali gnment was finalize d, ma nual te st swe eps of the flap thro ugh f ull ang ular excursion were  made to est ablish prop er integrated functio n of t he flap with the vehicle. With pro per positio ning  establi shed, the flap s were  match ed-drill ed to the ve hicle with un der-sized h oles (to allo w potential future  fine positio n adju stment), and faste ned temporarily.   

The final pha se beg an by  attaching th e EMA arc to t he flap at the foot. This process inv olved spe cial  tooling to p rotect the flap and aid i n the positio ning of the heavy m oving pa rts of  the EMA. Final mating of   the arc to the  foot and the flap wa s follo wed by m anual movement of the entire i ntegrate d EMA, arc, foot  and flap  system while b olted to the  vehicle. With su ccessful full -range m oveme nt establi shed via the se  manual swee ps, the tempo rary faste ners were secured in prep aration for po wered avionics tests. 

Finally, with all part s preci sely align ed, che cked, and bolted toget her, the enti re vehicle avi onics sy stem   was po wered up, flight softwa re was loa ded i nto onbo ard comp uters,  and compu ter co ntrolle d  movement s were condu cted. Onbo ard softwa re provided test-mov ement seque nces similar t o those that   would have  been u sed in flight. The computer cont rolled m ovements i ncluded moving th e flaps up and  387