of this interfa ce with the robotic a rm and the possi ble red esign of parts of the mech anism. More  thorough exploration of the me chanism  capabilities during qualifi cation would have reduced the  amount of wo rk ne eded later to adapt to  this new requirement. 

2) Config uratio n cont rol of th e entire p rocess, in cludin g CAD mo dels, drawi ngs, manufa cturing steps  and op eratio ns plan ning i s essential to succ essful inte gration of co mplex system s. 

Without rig orous config uration c ontrol, integratio n of the nume rous subsystems and com ponents o f  a compl ex system like ISS becom es nearly impo ssible. It is impossible for e ach person worki ng on   the proj ect to kee p track of everything that is bei ng don e, to unde rstand h ow chan ges to on e  subsystem affect others, a nd to co ordinate their efforts with out a controlled configuratio n, and a   clearly define d process fo r updatin g that configu ration. With rig orous configu ration co ntrol,  new  processes (i.e., Assembly  Analysis) have greatly r educed the risk in herent in first-time o n-orbit  assembly of ISS elements.  

3) The a nalysi s process mu st accommo date the need for configu ration control with the  need to  minimize CA D model size and complexi ty. 

Curre ntly, the state  of th e art i n computer  aide d desi gn and modelin g does not provide the  processing capability or storag e spa ce for fully detailed mo dels of the e ntire S pace Station to be  manipul ated. Therefore, si mplified models mu st be  built in orde r to perfo rm th e nee ded analyse s.  Controlling  the configu ration of the se simplifie d models, whi ch of ne cessity do n ot mat ch the  config uratio n-controlled master be comes ve ry difficult. The I SS-develop ed CA D mo deling   architectu re, wherein high-fidelity model s of indivi dual details can be ea sily pla ced in their correct  locations in an overall low-fidelity asse mbly, make s it possible to see the point s of current inte rest in   an assem bly in great detail,  without over loadin g processing capa bility or memory.  

4) Much benefit  can be realized by em phasizing communication b etwee n team s that are d esigning  similar hardware and utilizi ng com mon hardwa re across desi gns. 

A prime  exa mple of th e ben efits of this a pproach can be seen in  the va rious mechanisms  develop ed fo r berthi ng th e unpressu rized truss ele ments of ISS. E ach varia nt, designed by di fferent  groups to differing req uirements, buil ds upon  the others, with a commo n captu re latch used   throug hout. This commo nality re sulte d in a reduction in  required te sting and a nalysi s and i n a  reduction in crew trainin g. 

5) For compl ex interfaces su ch these on-orbit berth ing mechanisms it i s essential th at the engin eering  design, manu facturin g and CAD mo delin g teams work together thro ugh the entire  process. 

Comm on CA D mod els, first develop ed by the desig ners, were use d by the man ufacturi ng tea ms for  planni ng, the n updated  using as-built m easure ments by the assem bly analy sis team to  verify final fit   and fun ction. 

Berthing  mechani sms an d the a ssembly  processe s develope d for I SS are  an essential  comp onent of any  future ma nned ope ration s in space. Ren dezvo us and docking between different vehicles and assembly of   Space  Stations a nd la rge vehicle s in space will require comm on in terface s. Compatibility of new berthi ng  mechani sms with existing ones will be a requiremen t that will dri ve to a minimum num ber of commo n  berthin g interface s for all space vehicl es. A set of  viable interfa ces has n ow been develop ed, tested a nd  is in use. Certainly improvements will continue to be made, but they will fo llow the path deve loped by the  Internation al Space Statio n Program.   314