When an embattled US president, who as a Texan never visited the Johnson Space Flight Center in Houston, unveils plans for staffed missions to set up a lunar base and land on Mars, 10 years at the earliest after he becomes an ex-president, anyone become suspicious of an election stunt. Former Democratic Vice-president Gore made the following observation that seems to stand above the tedium of US politics, “[It is]… an unimaginative and retread effort to make a tiny portion of the moon habitable for a handful of people”. Much the same could be said of a Martian mission, when billions of Earthbound people find their homelands barely habitable. The word “hubris” (insolent pride) springs to mind, for scientists who support such pies in the sky, as well as for politicians in an election year. During the Apollo lunar missions the justification for sending people was that they could use their eyes, ingenuity and knowledge to collect samples. The fact is that planetary scientists on terra firma specified the landing sites and told the astronauts what to collect, and of course all the sample analyses were made on Earth. They did indeed revolutionise our understanding of how the Earth began its evolution and its record of bombardment by interplanetary debris. Human hands were needed then, because robotics (servo-mechanisms, machine vision and remote control) were too primitive to collect material efficiently. Within a month since Christmas Day 2003 three robotic laboratories and collecting systems have landed on the Red Planet. One, a marvel of miniature sophistication (Beagle-2) seems to have died on touchdown. The other two are NASA vehicles able to roam under close control and send back detailed close ups and make some analyses. At the same time, imaging systems in orbit are providing more detail about Martian surface geology and landforms than exists for our home world, despite the efforts of geologists over the last two centuries. Given 10 years or so of further robotic development, surface rock samples and cores of soils could be returned. Look at it this way; a staffed mission has to send and return say 2 or 3 humans weighing upwards of 150 kg, along with all their requirements for a long mission, plus various weighty safety shields. Given the same spacecraft without passengers, we are looking at more than half a ton of samples that could be returned for a fraction of the cost, if 2 or 3 humans forewent the massive privilege of standing on a not too welcoming planetary surface for a couple of days.
What issues remain to be addressed scientifically on the lunar and Martian surfaces? For the Moon, the far side remains little known, but on which no human mission is likely to be landed, because it would be devoid of constant communication. More samples of rock from the side that faces Earth would always be welcome, but robotics can grab them and bring them back. For Mars the question is that of early life, but mainly to see if it did emerge in what increasingly seem likely to have been favourable albeit brief conditions, and if traces remain. Geological matters are secondary to that, but nonetheless fascinating. Yet, Mars is a far more complicated place than the Moon, and to properly grasp its evolution and composition, and whether it spawned and supported organisms, needs more than one mission to one site for a few days – all that a staffed mission could realise. The Bush “vision” already threatens the single most important scientific instrument in orbit – the Hubble telescope. The cost of developing human expeditions to both Moon and Mars would probably sterilise funds for more ambitious robotic exploration. Indeed robots could invalidate their entire scientific justification long before the astronauts set off. In order to check out the health risks of lengthy space missions, the so-far functionless International Space Station is to have life breathed into it, in the manner of a Frankensteinian white elephant. The ageing and dangerous Shuttle fleet is to be kept alive, solely to service this legacy of Ronald Reagan’s bizarre two terms of office. But, let’s live in the real world. Who would stump up the funds necessary for a proper planetary exploration programme, when there will be no-one gazing steely-eyed into the camera saying how awed they are to be on Mars, Mr President?