A very exciting year for planetary exploration

All going well, on December 25 at 2:45 am GMT, The Beagle 2 lander will touch down on the Isidis Planitia impact crater on the surface of Mars. This lander, which has a planned six month mission on the Martian surface, was developed and built in Britain and forms part of the European Space Agency’s Mars Express mission, from which Beagle separated on December 19. Mars Express will be inserted into Mars orbit at 3:00 am GMT on December 25 for a planned mission of between one and two years.

A mockup of the Beagle 2 lander at Sandy Quarry, Bedfordshire. (All rights reserved Beagle 2).

All going well, Beagle will be followed by two identical American landers that are scheduled to land in January. These two Mars Exploration Landers will have wheels and will be fully mobile when they arrive, being able to travel distances of up to 40 metres per day. (Everything important is self-contained in the Rover, and the rest of the lander is just a delivery vehicle). Spirit will land in the Gusev Crater on January 4 at 4:35 am GMT on January 4, and Opportunity will land on Meridiani Planum on January 25 at 5:05 am GMT. If all three missions land successfully, we should be getting back lots of interesting data on the red planet.

Projection of the Mars Exploration Rover leaving the lander shell. (Copyright NASA/JPL).

If all are successful (about which there is a caveat that I will get to in a moment) these will be the fourth, fifth and sixth successful lander missions to arrive on Mars, after Viking 1 and Viking 2 in 1976 and Mars Pathfinder in 1997. (I am excluding the Soviet Mars 3 mission from 1971 which transmitted data for only 20 seconds after an apparently successful landing).

All three missions will use the landing method pioneered by Mars Pathfinder in 1997. This consists of parachutes, followed by the firing of small rockets for further deceleration, and finally inflated airbags that will cushion the landers as they bounce around a bit after impacting with the surface of Mars. (This method only really works for landing on relatively low lying areas of the Martian surface, as the first (parachute) stage requires the lander to pass through a fair amount of Martian atmosphere before reaching the surface, and there is not enough atmosphere for a landing on the elevated sourthern polar region for instance. In addition, there is not enough sunlight to power a polar mission from solar cells, and more expensive nuclear power sources are needed, making a polar lander a much more difficult undertaking).

Projected landing sites of the three Mars landers. Note they are all fairly equatorial.

Beagle is concerned principally with looking for evidence of life on Mars. It will be searching for the presence of water, carbonate minerals, organic compounds, will be studying atmospheric composition, the geological nature of rocks, and other environmental factors. The two Mars Exploration Rovers have broadly similar missions to this, being concerned with looking for evidence of water, surveying the geological properties or Martian minerals, and (interestingly) comparing results of ground based instruments with data recovered from orbiting Mars missions, in order to calibrate instruments property for orbiting missions. And of course, all three missions will be taking and radioing back lots of really cool photographs.

This is all terrific, and I am looking forward to seeing what these landers find more than anything. However, in the case of Mars exploration, one shouldn’t take anything for granted. Although there have been some tremendous successes, the history of Mars exploration is fraught with failure. The United States and Soviet Union took seven attempts to get the first successful flyby mission (ultimately the American Mariner 4 mission in 1964) there at all. After this there were about another ten failed Soviet missions and US missions (although US missions were generally successful, and one or two Soviet orbiting missions succeeded too) prior to the successful (but very expensive) Viking Landers in 1976.

Overall, there were far more failures in Mars missions than anywhere else, and this “Curse of Mars” continued when the Soviets lost two further missions in 1988, the US lost an orbiter in 1992, and the Russians lost an orbiter in 1996.

The US commenced a new phase of Mars exploration in 1996, and this started well with Mars Pathfinder and Mars Global Surveyor in that year. Unfortunately, though, Mars Climate Orbiter and 1998 and Mars Polar Lander in 1999 also failed. (The loss of this last mission was a particular tragedy, as this was the most complex Mars lander probably ever, and was intended to look at the extremely interesting carbon dioxide icecap on the southern polar region. The current missions are probably less interesting than this one would have been).

Since then though, the 2001 Mars Odyssey orbiter (which has mapped Mars’ geology and radiological properties from orbit) has been highly successful. However, just to remind us that Mars is hard, the Japanese Nozomi orbiter was abandoned by Japanese controllers after repeated electrical failures just last week.

So, we can hope. I think I may be up on Wednesday night with a bottle of champagne to open when I hear that Beagle is down and transmitting data. Landing on another planet is tricky. So I will wish everybody involved in these missions the best of luck.

Now that is Mars. Later in the year may be even better. We all got a little sad three months ago when the Galileo orbiter was crashed into Jupiter’s atmosphere after eight years orbiting Jupiter. Somehow it was reassuring to know that the orbiter was there to look at anything interesting that might be happening in the Jovian system. While JPL does have another Jupiter orbiter being planned, it will not launch until at least 2011, so we will have to do without such observations for a while. The good news, however, is that we will be able to look at Saturn instead, as the Cassini orbiter will be arriving in Saturnian orbit in July 2004. The mission will do much interesting science, looking at Saturn itself, Saturn’s rings, and the various satellites. In particular Cassini will be dropping a probe into the opaque atmosphere of Titan, Saturn’s largest moon. This mission is initially planned for four years, but judging by past successes it may well go for significantly longer than that.

Artist’s impression of Cassini during its Jupiter flyby (Artist: David Seal. Copyright NASA/JPL)

Composite image of Saturn taken from Cassini on October 21, 2002. The dot in the upper left is Saturn’s largest moon Titan. (Copyright NASA/JPL)

While looking at data from planetary missions has always been a marvelous and fascinating thing to do, it has become so much easier in recent years with the advent of the internet. These days, ordinary people like me can look at images almost as soon as the scientists running the mission can. (I remember as a teenager waiting for magazines containing detailed photographs of Uranus from Voyager 2 in 1986 to arrive in Australia by sea mail). This is of course splendid. However, with the Beagle Mars mission, there is a new development.

As far as I can tell, it is the first plantetary mission with a blog.

(Thanks to Jay Manifold for some of the information and links in this post).