Is there a good reason to spend so much money--DAWN carries a $446 million price tag

MJMANDALAY

Registered User
Jan 26, 2005
13,145
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#1
The designers at NASA are preparing to fly what may be the feeblest spacecraft they've ever built--and they couldn't be prouder of it. Never mind the decades of unmanned probes that have gone roaring into the void at tens of thousands of miles per hour, fire streaming from their tails. The new ship will putt-putt into interplanetary space under the power--if that's even the word--of an engine that accelerates by barely 15 m.p.h. (24 km/h) per day, or zero to 60 in more than half a week. Yet the places the ship is going--and the remarkable way it will get there--could open an entire new era in space travel.

The odd duck of a spacecraft, scheduled to launch in September, is known simply as Dawn, and its destinations are the asteroid Vesta and the dwarf planet Ceres, mysterious bodies orbiting in the belt of rubble that circles the sun between Mars and Venus. NASA vehicles have been this way before, but they've usually been just passing through on their way to the planets in the outer solar system. This time the asteroid belt itself will be the destination, and the ship will get there courtesy of the young technology of ion propulsion.

Like any other spacecraft, Dawn will have to be muscled off its launchpad by a conventional rocket burning conventional propellant. Once it climbs to near Earth space, however, everything will change. Of all the things that add weight to a spacecraft, fuel presents the most problems. The farther you're going, the more propellant you need, but every pound of it you add means more mass the engine must propel, which requires more fuel still, and on and on. A spacecraft like Dawn, which is designed not just to fly by its two targets but also to settle into orbit around them, would require a massive load of onboard gas.

"We're going to two bodies," says systems engineer Marc Rayman of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "If we wanted to go to even one of them, we'd normally have to carry several tons of propellant and would need one of the largest rockets in the U.S. inventory to get it off the ground."

Ion propulsion sidesteps that whole mess. Rather than rely on common combustible fuel, it uses xenon gas, a comparatively light 937 lbs. (425 kg) of it loaded into a compact 72-gal. (273 L) tank. A jolt of electricity energizes the gas, causing xenon ions to shoot out the back of the ship at 77,000 m.p.h. (124,000 km/h). A stream of charged atoms has somewhat less oomph than a burst of fire--less force than the weight of a single piece of paper, in fact--but over time it adds up. "It's acceleration with patience," says Rayman. "In the four days it takes to increase speed by 60 m.p.h., we'll use only 2 lbs. of propellant. If we keep thrusting, however, we can achieve extremely high speed." Indeed they can. By the time Dawn completes its four-year journey to the neighborhood of Vesta, a trip made longer by the slow acceleration, it will have sped up by 24,500 m.p.h. (39,400 km/h) and will be tearing along as fast as any interplanetary ship has ever propelled itself.

There's good reason to spend so much time and money--Dawn carries a $446 million price tag--getting to Ceres and Vesta. The composition and reflectivity of the bodies suggest they were formed within the first 3 million years of the solar system's life, whereas Earth was something of a late arrival, coming along about 27 million years later. A close look at Ceres and Vesta, then, is a close look at a local cosmos that our planet wasn't even around to see. "These two objects are our best opportunity for going back into time," says Christopher Russell, professor of geophysics and space physics at UCLA.

Not only are the little worlds old, but they're also odd. Vesta, which measures about 330 miles (531 km) at maximum diameter, or roughly the width of Arizona, is thought to account for 1 out of 20 meteorites that strike Earth, while Ceres, which is closer to us, provides none. One reason might be simply that Vesta is made of denser stuff, material that when it breaks away can remain intact through the long journey to Earth. "Ceres is not very thick," says Russell, "and whenever there's an impact, it knocks off ice and a lot of dust that doesn't survive the trip." That ice makes Ceres intriguing in its own way. At 590 miles (950 km) in diameter, it could be a surprisingly dynamic place, with an ice crust over a rocky interior and watery flows periodically resurfacing it.

To ensure that it can uncover the secrets of both worlds, Dawn will ease itself into a six-month orbit around Vesta, then climb gradually back out and fly on to Ceres, which it will orbit for about five months. This is the part that would have been simply too fuel intensive for an ordinary spacecraft. Dawn, by contrast, should have enough xenon left over after its Ceres stay that mission planners might even consider sending it on to a third destination.

No matter what the ship eventually reveals about Vesta and Ceres, NASA believes a successful mission could help establish ion technology as the propulsion system of choice for any mission in which the need for fuel is high and the need for speed is low. "Because of ion propulsion," says Rayman, "Dawn can explore the last unexplored worlds in the solar system." Not bad on a single small tank of gas.



http://www.time.com/time/magazine/article/0,9171,1642892,00.html
 

Creampier

I have to return some videotapes!
It's My Birthday!
May 11, 2007
748
0
366
Somerville, NJ
#5
I wish NASA would get privatized! It's easier said than done, but fuck... that's a lot of taxpayer money for pictures!
 

THE FEZ MAN

as a matter of fact i dont have 5$
Aug 23, 2002
42,693
9,691
848
#6
i love space, i want flying cars and the enterprize, we should have a moon base twenty years ago
 

HummerTuesdays

Another girrrrl!!!
Apr 24, 2005
7,347
0
261
On the road to ruin
#7
This is just a drop in the bucket compared to the rest of our money the government is wasting. At least we get something out of it.
 

weakside

He was stupid. I was lucky. I will visit him soon.
Dec 9, 2004
3,871
0
0
California
#8
This is the one endeavor our government concerns itself with in which I will never question the price tag. A huge part of what made humans human is our curiosity.

I can't say for sure it will ever help us, but just the fact it might makes it important to try.
 

abudabit

New Wackbag
Oct 10, 2004
14,802
0
0
#10
We spend 200 times as much on keeping our soldiers amongst the streets in Iraq.
 

Sprite

permanent case of the Moooondays
Apr 27, 2005
3,834
2
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Jersey
#11
Ion propulsion is some amazing shit.
 

Kris_LTRMa

LoseTheRadio.net's Ma
Nov 17, 2006
9,749
1
333
right where I wanna be
#12
This is just a drop in the bucket compared to the rest of our money the government is wasting. At least we get something out of it.

I can think of better ways for the government to spend that drop in the bucket on terra firma then up in space. I really don't care whether or not there's water on Mars.
 

doktormoo

Apple, BMW Motorcycles, Cigar and O&A junkie.
Feb 11, 2005
233
0
0
Arkansas
#14
The amount is not what is important, for that mather, neither are the supposed benefits. A government owned monopoly at taxpayer expense is the issue. Creampier is right, privitizing things like NASA, the Post Office etc. would be a benefit to the country. Better service, better quality, better decisions. There is not too much that a government does well and it should stick to a few, constitutionally defined tasks. I do not think that space travel would be one of them.
 

Fr. Dougal

Registered User
Feb 17, 2004
5,853
0
216
#15
NASA's budget is something like one and a half pennies out of every tax dollar. Or something like that. I forget.

I had the opportunity to tour the Kennedy Space Center with a reporter friend once... and this one guy who ran one of the shuttle's hangars had a weird answer for the question "Why spend so much on NASA?" He said "Protein crystals."

After looking at him like he was nuts, he explained. Protein crystals are what they use to develop medicines on everything from aspirin to curing cancer and AIDS. You need them to figure out how proteins work/don't work in the body. Growing them on earth takes forever, and they grow uneven in gravity. Not much of what's grown can be used. But in orbit, crystals grow in a week what it takes 3 months down here. And they grow with perfect structure.

So this guy said... one day, they're gonna call down from the station, saying "Guys, um... yeah we just cured cancer."

It was such a different answer to the "Why spend so much" question... and it made sense. It stuck with me. I asked him a follow up... Why wouldn't NASA promote THAT as an answer? His response... NASA's managers don't always know what the hell they're doing.
 

MJMANDALAY

Registered User
Jan 26, 2005
13,145
1
0
#16
Update

Tue Sep 25, 10:15 PM ET
CAPE CANAVERAL, Fla. - NASA is about to embark on an unprecedented asteroid-belt mission with a spacecraft aptly named Dawn. The 3 billion-mile, eight-year journey to probe the earliest stages of the solar system will begin with liftoff, planned for just after sunrise Thursday. Rain is forecast, however, and could force a delay.

Scientists have been waiting for Dawn to rise since July, when the mission was put off because of the more pressing need to launch NASA's latest Mars lander, the Phoenix. Once Phoenix rocketed away in August, that cleared the way for Dawn.

"For the people in the Bahamas, on the 27th will be one day where they can say that Dawn will rise in the west," said a smiling Keyur Patel, project manager from the Jet Propulsion Laboratory in Pasadena, Calif.

Dawn will travel to the two biggest bodies in the asteroid belt between Mars and Jupiter — rocky Vesta and icy Ceres from the planet-forming period of the solar system.

Ceres is so big — as wide as Texas — that it's been reclassified a dwarf planet. The spacecraft will spend a year orbiting Vesta, about the length of Arizona, from 2011 to 2012, then fly to Ceres and circle there in 2015.

Dawn's three science instruments — a camera, infrared spectrometer, and gamma ray and neutron detector — will explore Vesta and Ceres from varying altitudes.

"In my view, we're going to be visiting some of the last unexplored worlds in the inner solar system," chief engineer Marc Rayman said Tuesday.

Because Vesta and Ceres are so different, researchers want to compare their evolutionary paths.

No one has ever attempted before to send a spacecraft to two celestial bodies and orbit both of them. It's possible now because of the revolutionary ion engines that will propel Dawn through the cosmos.

Dawn is equipped with three ion-propulsion thrusters. Xenon gas will be bombarded with electrons, and the resulting ions will be accelerated out into space, gently shoving the spacecraft forward at increasingly higher speeds.

"It really does emit this cool blue glow like in the science fiction movies," Rayman said.

NASA tested an ion engine aboard its Deep Space 1 craft, which was launched in 1998. Ion engines have been used on only about five dozen spacecraft, mostly commercial satellites.

Dawn also has two massive solar wings, nearly 65 feet from tip to tip, to generate power as it ventures farther from the sun. Ceres is about three times farther from the sun than Earth.

NASA put the cost of the mission at $357 million, but said that does not include the Delta II rocket. Officials refused Tuesday to provide the cost of the rocket, saying that was proprietary information
.
 

WaddleDoodle

Creepy? We're the CIA. It's what we do.
Mar 15, 2005
601
0
0
Arlington, VA
#17
This is the one endeavor our government concerns itself with in which I will never question the price tag. A huge part of what made humans human is our curiosity.

I can't say for sure it will ever help us, but just the fact it might makes it important to try.
Adding my little fun fact: NASA is the only government program to pay for itself 13 times over. Mostly though patents and the like

Some stuff we've gotten out of the space program:

Teflon
Barcodes (So essentially, our entire retail establishment)
Cordless powertools
Firemen's air tanks
GPS
Computer technology
Safety features for moderns vehicles

The list goes on quite a bit.

EDIT: Just found this nifty site:
http://www.thespaceplace.com/nasa/spinoffs.html#health
 
Jun 2, 2005
15,516
4
0
Dallas
#18
Adding my little fun fact: NASA is the only government program to pay for itself 13 times over. Mostly though patents and the like

Some stuff we've gotten out of the space program:

Teflon
Barcodes (So essentially, our entire retail establishment)
Cordless powertools
Firemen's air tanks
GPS
Computer technology
Safety features for moderns vehicles

The list goes on quite a bit.

EDIT: Just found this nifty site:
http://www.thespaceplace.com/nasa/spinoffs.html#health
Don't forget Temperpedic beds!
 

TheDrip

I'm bi-winning.
Jan 9, 2006
5,051
3
228
#20
Photon torpedos.



....um, wait. nevermind.
 

martianvirus

READY THE ANALPROBES!!!!!!!!
Nov 20, 2005
19,062
134
268
Las Vegas, NV
#21
Ion is for shit dicks. Soon we will be able to warp space and use worm holes.