Back in 1977, the Voyager space probes began their endless journey into space carrying messages of goodwill from Jimmy Carter, night chants from the Navajo Indians and, oddly, a note from the Chinese which translates into English as "Have you eaten yet?" Some, I know, thought it a bad idea to let other life forms know we were here in case they deciphered the Chinese message and thought: "Now you come to mention it, I am a bit peckish. So I’ll pop over and try some of that Jimmy Carter."

I was a happy teenager, though, and I liked to imagine that within my lifetime people from other planets would drop by to say hi.

Unfortunately, I hadn’t really done the maths. Although the probes are screaming through space at 35,000mph, making them the fastest machines made by man, it was announced a few years ago that only now, over thirty years into the mission, are they leaving the solar system. In terms of Earth travel, this is the same as reaching the end of your garden path at the beginning of a round-the-world cruise.

Already their cameras and sensors have sent back enough data to fill 6,000 sets of Encyclopaedia Britannica and, of course, most of the information has whipped the conspiracy theorists into a frenzy. It seems they’ve managed to find some rock formations on a newly discovered moon called Miranda that are strangely similar to carvings recently discovered in Peru.

Now, though, the real excitement begins, because the Voyagers are out past Pluto in a zone known as the termination shock. The solar winds have dropped from a million mph to the speed of sound and soon the probes will enter a region known as the Oort cloud, which is a nursery for comets. After this has been cleared, they will encounter Sirius, the brightest star in the night sky, and the first real chance that the Navajo night music will be heard by a real Jedi Knight.

Don’t, however, expect this to be a live, televised extravaganza. The signal from the probes is already 20 billion times weaker than the power you get from a digital watch. So the pictures might be blurred. To make matters worse, the nearest either craft will get to Sirius is 25 trillion miles and, what’s more, this won’t happen for 296,000 years. That’s 295,980 years after the Voyagers run out of fuel and battery power.

This mission was fatally flawed from the start. What are the chances of an alien civilisation detecting a lifeless one-ton lump passing by at a distance of 25 trillion miles? And even if they do have the ability to retrieve the craft, what are they to do with the record they find on board? If we wanted anyone to translate the message, why were there 55 of them, all saying different things in different languages? And why for God’s sake send them a record of Navajo night chants? If you want people to come hundreds of light years for a concert, send them the Rolling Stones or Hawkwind.

I have no doubt that there will already be many people claiming that the £500m that this mission has cost could have been spent on incubators for babies and research into Aids. It’s easy to sympathise with this argument. On Earth, everything is finite and very, very small. We think it’s a long way to Sydney and that Everest is large. Which is why I thought the Voyagers would be broadcasting to Mr Spock within my lifetime.

They told me the craft had batteries that would last for 50 years and I was impressed because the batteries in my tape recorder are out of juice after 50 minutes. But 50 years in space is nothing; 35,000mph is nothing; our solar system is nothing. Sending a probe out there hoping it will pass near to an alien is like . . . I was going to say it’s like an ant walking through the Sahara hoping to meet a grasshopper coming the other way. But it’s not like that at all. It’s not even like amoebas playing hide-and-seek in the Pacific. It’s bonkers and futile.

And yet. What are we supposed to do now we know every last detail about our own planet and that even the nastier bits like North Dakota and Spain are better than the best bits of our own solar system? Do we just sit here, twiddling our thumbs? That’s what panda bears do, and earwigs. How far do you think we would have come as a species if Christopher Columbus had decided Lisbon was nice enough? Or if Alexander Fleming had reckoned we had enough drugs already?

What’s the first thing a child does when you go on holiday? He explores. It’s in our nature. Alexander the Great wept when he surveyed the breadth of his domain because he had no more worlds to conquer. So we have to keep on building more Voyagers and we have to keep on firing them out there.

Only let’s stop bothering with the messages of goodwill and Navajo noises. And let’s forget the political correctness of getting the Chinese to chip in with a supper invitation. If we really want the Klingons to come all the way over here we have to make their journey worthwhile.

Now, I posted this some years ago on Multiply and it's here now because I found out something new and relevent a few months ago.

The batteries on spacecraft are powered by uranium 238 (I think. Don't quote me on that precisely because I'm relying on memory now). NASA, being a private organisation can't produce it's own U-238. NASA had been buying it from Russia and, in the absence of much other use for the stuff, the US government stopped producing its own.

However the ten year contract with Russia has run out and the new price is at least ten times what it used to be. Besides, Russia has its own space program and supplies the EU so they're not bothered if the US buys or not. China and India also have their own space programs to supply. Especially China now that they're planning manned trips to the Moon and Mars.

There's only one other Country in the world that produces enough U-238 and wants to sell it...........Iran.

Oh the Irony. If the US wants to send up more than the fourteen craft it already has fuel for then it will have to reduce the sanctions it's placed on Iran. And to add insult to injury Iran won't trade in US dollars. It'll have to be euros, or yuan or maybe gold.