Small Satellites May Play Big Role In Future Interplanetary Missions
By Brian Berger
of small satellites say that tiny spacecraft have potentially big roles to play
in planetary exploration.
small satellites—generally spacecraft weighing around several hundred kilograms—are
confined largely to low Earth orbit where they perform remote sensing missions,
conduct science operations and serve as technology testbeds
and communication relays.
forward thinkers are already looking ahead to interplanetary missions and see
small satellites as a good fit with the space exploration agendas outlined by
the world’s spacefaring nations.
European Space Agency, for example, is taking a look at a low-cost, multiple
spacecraft Venus mission that would utilize small satellite technologies,
including a small, deployable weather balloon of sorts, to study the planet.
The Indian Space Research Organization last year short listed a gravity-mapping
nanosatellite for inclusion on its Chandrayaan-1
lunar orbiter mission.
Phipps, a senior engineer at the British small satellite company Surrey
Satellite Technology Ltd., said his team recently completed a so-called
technology reference study funded by the European Space Agency to identify the
technologies and design philosophy needed for the proposed Venus mission.
his team spent 18 months and several hundred-thousand Euros developing a
mission concept featuring two orbiters packed with miniaturized instruments and
a tiny aerobot that would be
dropped into Venus’ corrosive atmosphere.
The aerobot, consisting of an instrument-laden gondola
suspended from a balloon, would add about 90 kilograms of mass to one of the
orbiters, a data relay satellite that would be placed in a highly elliptical
orbit around Venus. The aerobot would be dropped into
Venus’ atmosphere where it would float at an altitude of 55 kilometers,
circumnavigating the planet several times during its projected 15- to 22-day
orbiter would be packed with miniaturized instruments and would circle the
planet at a lower altitude, imaging the planet and making scientific
proposed orbiters themselves would be relatively small for interplanetary
spacecraft, weighing several hundred kilograms apiece. NASA’s Mars
Reconnaissance Orbiter, in contrast, will weigh nearly 2,200 kilograms at
launch and require an Atlas 5 rocket to reach orbit.
satellites and the inflatable robotic stowaway would launch on a single
Russian-built Soyuz rocket equipped with an upper stage. The total projectedmission cost, Phipps said, is several hundred-million dollars, or about
one-tenth of what the U.S.
and Europe spent on the Cassini-Huygens
mission to Saturn.
proposed Venus Entry Probe mission is only one of a half-dozen mission ideas
the European Space Agency is considering as it looks ahead to the 2015-2025
timeframe to try to understand what technologies it should be investing in now.
the technology needs of the Venus Entry Probe mission are considerable and
include: highly protective cover glass to shield imaging instruments from acid
rain; steerable planar array antennas to increase data
return from the aerobot; higher efficiency solar
cells; low-mass structural components that can withstand the planet’s corrosive
environment; and lightweight thermal protection system for the aerobot’s entry vehicle.
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