Feeds

Solar-powered ion drive asteroid probe set for launch

Not much va-va-voom, but very economical

Choosing a cloud hosting partner with confidence

NASA has confirmed that the "Dawn" space probe to the asteroid belt will indeed launch on Saturday, ending speculation that the mission might be delayed.

After launching, Dawn will spend four years in transit to the asteroids, circling the Sun twice and gaining a "gravity assist" on the way by making a close approach to Mars.

Dawn Mars Vesta

Planned voyage of the Dawn space probe

In 2011, Dawn will go into orbit around Vesta, one of the larger rock-like asteroids in the Belt. After around five months studying Vesta, the probe will depart in early 2012 and complete most of a further circuit round the Sun, finally catching up with Ceres in 2015 and going into orbit around it. Ceres is a large example of the other main asteroid type, thought to be largely icy in composition.

The Dawn mission will be the first to go into orbit around a Belt asteroid, and also the first to orbit two different bodies. This unusual flight profile would be all but impossible, according to NASA, were it not for the spacecraft's innovative propulsion system.

Dawn will lift off from Earth aboard a conventional, chemical Delta II rocket, but its journey to the asteroids will be propelled - apart from the helping hand from Martian gravity - by means of an ion drive.

In an ion drive, thrust is still provided by throwing stuff out of the exhaust just as with a regular rocket. The difference is that rather than chemicals burning and expanding to throw themselves out of a combustion chamber, Dawn's Xenon propellant is squirted out of its back end using electrical power generated by solar panels.

As one might expect, this produces an exceptionally feeble thrust; equivalent to about 0.02lb. The clever bit is that the ion engine achieves this thrust very economically, using only a tiny amount of propellant, because it accelerates the Xenon-plasma exhaust to such a high velocity.

Dawn takes ages to squirt out a given amount of fuel, but when the ion drive finally does so it has achieved much more with it than a chemical rocket could have done. All this makes the multi-asteroid flightplan achievable within the NASA budget.

Now that NASA has addressed some technical concerns, it appears that Dawn's Saturday launch is a go, and then it's just four years until it gets to Vesta. ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
GRAV WAVE DRAMA: 'Big Bang echo' may have been grit on the scanner – boffins
Exit Planet Dust on faster-than-light expansion of universe
Mine Bitcoins with PENCIL and PAPER
Forget Sudoku, crunch SHA-256 algos
SpaceX Dragon cargo truck flies 3D printer to ISS: Clawdown in 3, 2...
Craft berths at space station with supplies, experiments, toys
'This BITE MARK is a SMOKING GUN': Boffins probe ancient assault
Tooth embedded in thigh bone may tell who pulled the trigger
DOLPHINS SMELL MAGNETS – did we hear that right, boffins?
Xavier's School for Gifted Magnetotaceans
Big dinosaur wowed females with its ENORMOUS HOOTER
That's right, Doris, I've got biggest snout in the prehistoric world
Japanese volcano eruption reportedly leaves 31 people presumed dead
Hopes fade of finding survivors on Mount Ontake
That glass of water you just drank? It was OLDER than the SUN
One MEELLION years older. Some of it anyway
Canberra drone team dances a samba in Outback Challenge
CSIRO's 'missing bushwalker' found and watered
NASA rover Curiosity drills HOLE in MARS 'GOLF COURSE'
Joins 'traffic light' and perfect stony sphere on the Red Planet
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
The next step in data security
With recent increased privacy concerns and computers becoming more powerful, the chance of hackers being able to crack smaller-sized RSA keys increases.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.