Rogue (satellite) hunter

Paul Raven @ 13-10-2009

Things are going to get a little busier up in geostationary orbit… not only are there destined to be an increasing number of broken satellites cluttering up this important orbital region, but soon there’ll be little robot repair bots flying around up there trying to fix them (or push them out of the way):

Their robots will dock with failing satellites to carry out repairs or push them into “graveyard orbits”, freeing vital space in geostationary orbit. This is the narrow band 22,000 miles above the Earth in which orbiting objects appear fixed at the same point. More than 200 dead satellites litter this orbit. Within 10 years that number could increase fivefold, the International Association for the Advancement of Space Safety has warned.

Klaus Landzettel, head of space robotics at DLR, said engineering advances, including the development of machines that can withstand temperatures ranging from -170C (-274F) to 200C (392F), meant that the German robots will be “ready to be used on any satellite, whether it’s designed to be docked or not”.

Hellooooo, orbital commercial warfare! Rival communications company squeezing you out in a particular region? Not any longer – not once their sat takes an unscheduled trip to the Lagrange point!


Air-gunned to orbit, plasma thrust to Mars

Paul Raven @ 08-10-2009

Here’s another prospect to add to the list of alternatives to rocketry, if only for launching inert and non-fragile stuff like fuel or water into orbit. It’s a dirty great air-gun, basically:

At the Space Investment Summit in Boston last week, Hunter described a design for a 1.1-kilometre-long gun that he says could launch 450-kilogram payloads at 6 kilometres per second. A small rocket engine would then boost the projectile into low-Earth orbit.

While humans would clearly be killed and conventional satellites crushed by the gun’s huge g-forces, it could lift robust payloads such as rocket fuel. Finding cheap ways to transport fuel into space will lower the cost of keeping the International Space Station in orbit, and in future it may be needed to supply a crewed mission to Mars.

The gun would cost $500 million to build, says Hunter, but individual launch costs would be lower than current methods. “We think it’s at least a factor of 10 cheaper than anything else,” he says.

A factor of ten is a lot of money, meaning that initial investment could probably be recouped pretty fast. But is a Jules Verne-style cannon a sexy enough idea to attract the funding? It’s limited range of cargo will probably count against it, for a start.

Meanwhile, the Ad Astra company is making strides with its prototype VASIMR plasma engine, which will hopefully be way more efficient than traditional thruster designs. Fitting one to the ISS could save literally tonnes of orbit-adjustment fuel expenditure per year, and (once the tech is scaled up) plasma engines could get a spacecraft to Mars in little over a month. Here’s a brief video if the VASIMR being tested:

It’s a bit quieter than a regular rocket, isn’t it? But still more exciting than a big air-gun… which may partly explain the enduring romance of rocketry.


Cleaning up in orbit: ways to remove proliferating orbital crud

Paul Raven @ 13-03-2009

map of orbiital debris around Earth - courtesy NASASpace isn’t empty at all – it’s full of crap, much of it (unsurprisingly) put there by us. And much like the rubbish we leave elsewhere, orbital junk is becoming a serious problem:

The volume of man-made space debris has grown so large that scientists say garbage now poses a bigger safety threat to the U.S. space shuttle than an accident on liftoff or landing. The International Space Station occasionally fires thrusters to dodge junk.

So, what can you do? There are plenty of ideas, many of which sound like they were ganked straight from old sf dime novels:

Among the suggestions: launching big nets and large magnets to snag refuse, or using high-energy lasers to atomize debris. None of these ideas is feasible. Magnets would be useless because spacecraft contain almost no iron. Nets are almost uncontrollable. Blasting debris, meanwhile, would simply create smaller remains that would be tougher to track and produce a vast haze of shrapnel, experts say.

In short – the jury’s still out, and the problem still needs fixing. If this was a Ben Bova story, some plucky risk-taking entrepreneur would step in and make his fortune in short order…

… from which we can only conclude that life isn’t a Ben Bova story (at least, not yet). [via SlashDot; image coutesy NASA]


Rockets not jets: the future of orbital launch

Tom James @ 04-03-2009

rocketA fascinating article on the pros and cons of air-breathing spacecraft vs. rockets for orbital launch at Short Sharp Science:

Trying to build a spaceship by making airplanes fly faster and higher is like trying to build an airplane by making locomotives faster and lighter – with a lot of effort, perhaps you could get something that more or less works, but it really isn’t the right way to proceed. The problems are fundamentally different, and so are the best solutions.

[image from jurvetson on flickr]


US and Russian satellites collide

Tom James @ 12-02-2009

satellite_dieOn Tuesday a satellite owned by the US company Iridium collided with an inoperative Russian satellite nearly 780 km above the Earth:

The risk to the International Space Station and a shuttle launch planned for later this month is said to be low.

The impact produced massive clouds of debris, and the magnitude of the crash is not expected to be clear for weeks.

There are thousands of man-made objects orbiting the earth, but this is thought to be the first time two intact spacecraft have hit each other, the BBC’s Andy Gallacher in Miami says.

Unfortunately as Earth orbit becomes more and more crowded (the number of orbiting objects larger than 10 cm reached 10, 000 in 2007 and is still increasing) it increases the risk of a cascade effect, where one collision results in a cloud of debris that go on to cause more collisions resulting in millions of tiny fragments resulting in a major and ongoing hazard to space exploration.

Given the risk of hindering future space exploration – is it worth pushing for an Earth orbit cleanup (and is such an idea even feasible)?

[from the BBC][image from Joe Hastings on flickr]


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