special issue

physicsworld.comNews & AnalysisSpaceObama sets out NASA’s new mission to MarsUS President Barack Obama has an -nounced a new direction for NASAthat includes plans to send astronautsto an asteroid by 2025. Speaking lastmonth at Florida’s Kennedy SpaceCenter, the launching location forUS manned spaceflights, Obama alsocalled for a new “heavy-lift” rocketdesign to take astronauts on a missionto orbit Mars by the mid-2030s thatwill “eventually” be used to transporthumans to the Martian surface.In February, the Obama admin -istration said it was cancelling theConstellation programme – first proposedby George W Bush in 2004 –to develop new “Ares” rockets thatwould allow astronauts to return tothe Moon by 2020. Critics argued thatthe decision would surrender USlead ership in space and extinguishthe country’s vision of exploration.Neil Arm strong, the first man to walkon the Moon, called the decision“devastating” and a waste of the$10bn in vestment in Con stellationand the years of re search and developmentput into the project.The new plan involves retainingsome of Constellation’s technology,and NASA will now start to adaptits Orion crew capsule, which wouldhave hitched a ride on Ares to theA satellite that will probe how muchthe Antarctic and Greenland icesheets are contributing to global sealevelrises was successfully launchedfrom the Baikonur Cosmodrome inKazakhstan last month. The 7135mCryoSat-2 satellite, built by the Eu ro -pean Space Agency (ESA), will alsomeasure tiny variations in the thicknessof ice floating in the polar oceans.Weighing 700 kg, CryoSat-2 is noworbiting the Earth around its poles720 km above sea level.CryoSat-2’s main instrument is theSynthetic Aperture InterferometricRadar Altimeter (SIRAL), which isdesigned to send a burst of microwavepulses towards the Earth every 50 µs.The returning echoes can then beused to measure the distance betweenthe satellite and the sea ice, fromwhich a 3D map of the thickness offloating sea ice lying above sea levelcan be built to an accuracy of a fewInternational Space Station (ISS), asa kind of “space lifeboat” to re ducere liance on foreign vehicles for rescuemissions to the ISS.Obama also announced that NASAwill now invest more than $3bn in re -search on its heavy-lift rocket, with adesign expected to be complete “nolater” than 2015. The rocket, whichshould be complete a few years later,could be used for a trip to a near-Earth asteroid and then in a separatemission to Mars.Obama noted that he expects to still“be around” by the time US astronautsland on the red planet. “We willEurope’s ice mission successfully blasts offPhysics World May 2010Second time luckyThe European SpaceAgency’s CryoSat-2satellite will monitorice thicknesses.One giant leapNASA plans to sendastronauts on amission to orbit Marsby the mid-2030s,with a landing sometime after.centimetres. Researchers can thenuse this information to estimate thetotal mass and thickness of ice flow,the bulk of which (some 90%) liesunder the water.Set to remain in orbit for the nextthree years, CryoSat-2 will use thesame technique to measure changes tothe thicknesses of huge land-ice sheets,NASAP Carril/ESAac tually reach space faster and moreoften under this new plan, in ways thatwill help us improve our technologicalcapacity and lower our costs,” hesaid. “Nobody is more committed tohuman exploration of space than I am.But we’ve got to do it in a smart way.”The new plans also include modernizingthe Kennedy Space Center,as well as upgrading its launch capabilities.That process should createmore than 2500 extra jobs in the re -gion, compensating in part for joblosses that will occur due to the plan -ned end of the Space Shuttle programmethis year. Obama called aswell for NASA and other governmentagencies to develop a plan by 15 Au -gust for economic growth and job creationin the region.In his speech, Obama also ex -plained where an additional $6bnover the next five years for NASA willbe spent. First announced in his 2011budget request to Congress, this newmoney will go on increasing Earthbasedobservations, extending the lifeof the ISS by more than five years to2020, as well as working with privatecompanies to make getting to spaceeasier and more affordable.Peter GwynneBoston, MAsuch as those in the Antarctic andGreenland. CryoSat-2 is the satellite’ssecond incarnation after CryoSat-1was destroyed by a launch failure fiveyears ago. In 2006 ESA decided torebuild the satellite and launch it in2009, but delays led to the take-offbeing postponed until last month.“We are very much looking forwardto delivering the data the scientificcommunity so badly needs to build atrue picture of what is happening inthe fragile polar regions,” says physicistRichard Francis, project managerof CryoSat-2. CryoSat-2 is the third ofseven Earth-monitoring satellites thatform the ESA’s Earth Explorer programme.The first – the Gravity Fieldand Steady-state Ocean CirculationExplorer (GOCE) – was launched inMarch 2009, while the Soil Moistureand Ocean Salinity (SMOS) spacecrafttook off last November.Michael Banks9