The Draper Technology Digest - Draper Laboratory

HOW SMALL SPACE CAN ENABLEOPERATIONAL GCMOperational GCM must necessarily span Earth, but mustalso provide specific regional data that support local decisionmaking.A current challenge for orbital observations is thesparseness of data because of the dearth of generally largeobservational platforms that can take as long as weeks to repeatground tracks. Furthermore, most existing orbital platformsobserving important climate-driving properties were funded asone-of-a-kind, limited-life experiments with no plans in place totransition to a sustained observational capability. OperationalGCM will require that key climate parameters be monitoredglobally on a sustained basis with localized detail.Small Space allows a change in the paradigm for operationalGCM data collection using two approaches: Standardized small orbital buses can be produced in significantnumbers, providing services and interfaces to accommodateany one of a variety of small individual instrumentsor miniaturized sensor suites. (Note that some applicableinstruments and sensor suites have already been flighttested,while more exist in prototype form for many classes ofoperational GCM observations). These small orbitalplatforms can be carried either as secondary cargo on alreadyplanned launches or can be carried in clusters on small launchvehicles that can spread them out in an orbital plane ofinterest. By seeding each of several orbital planes with eachdesired class of instrument or miniaturized sensor suite,GCM observational coverage can become both truly globaland frequent at all localities. These attributes allow a smallnumber of ground stations the opportunity to collectrecorded data from many such satellites. Failure of anyindividual platform or sensor would have minor impactoverall on the completeness of the collected data set. Thesmall size of each platform, a greater tolerance for individualfailures, and sustained production of small satellites bythe dozen instead of as one-of-a-kind behemoths all provideopportunities for overall enterprise cost reduction. Limitedtotal required mass to orbit, emplaced using small launchersor secondary cargo space on already planned launches, alsooffers significant deployment cost savings. Small instruments or miniaturized sensor suites can beincorporated as secondary payloads onto larger, separatelyfunded orbital platforms serving other missions. Eachsatellite in the low-Earth orbit Iridium NEXTsatellite constellation has allocated a certain amount ofrentable payload space for this purpose, with powerand communication services already provided. Somecommunication satellites going to geosynchronous orbitnow also offer secondary payload space. Increased secondarypayload opportunities are likely to become available incoming years.GOING FORWARDAdvancing GCM to an operational capability is essential, but itmust be done affordably. Small space systems would allow classesof operational GCM capabilities to be emplaced incrementallyand cost effectively. To enable this, standardized, small satellitebuses should be developed that would support individual,operational GCM instruments or miniaturized sensor suitesin orbit. Applicable instruments and sensor suites that coveroperational GCM observational needs should be developed toa flight-ready maturity, accommodating use on individual smallsatellite platforms or as secondary payloads on larger platforms.Operational Global Climate Monitoring: A Critical Need That Small Space Can Enable19