Last night as I write this, NASA successfully launched the STEREO satellite (Solar TErrestrial RElations Observatory), a mission to observe the Sun literally in 3D. STEREO is actually two satellites: one will orbit the Sun ahead of the Earth, and the other behind. Since the angles to the Sun will be different for the two spacecraft, they can make observations that can be assembled into a three-dimensional view of our nearest star. Each probe packs a suite of instruments to look at how the Sun’s magnetic field is able to lift off and launch vast amounts of solar plasma out into space. These coronal mass ejections can travel as fast as a million miles per hour, and can damage satellites in Earth orbit. This "space weather" makes long term space travel difficult, and NASA is pretty serious about understanding how all this works. STEREO is a big step toward that.
I’m fascinated by STEREO’s orbit, too. Both spacecraft will use the Moon to swing them out into solar orbit, what’s called a "walkaway" orbit. Instead of being at a constant distance from Earth, they will, over time, drift away from the Earth, moving out about 22 degrees per year:
So, as time goes on, the angle between the two probes will increase. Eventually they’ll both be on the other side of the Sun as seen from Earth! That won’t happen for about 8 years, looks like, and the nominal mission profile is for two years. Usually, if a mission does well, it gets extended. But this one has a built in terminal stage! This is all pretty cool, and I’m very interested in seeing the images once they come down… but it’ll be a few months. First the probes need to be swung by the Moon, and that won’t happen for two months, and even then it’ll be a little while before the scientists and engineers can shake down the spacecraft and make sure everything is working up to snuff.
My congratulations to the STEREO team!
October 26th, 2006 at 11:52 am
Neato! I love unusual orbital profiles like this. When I first read about having two satellites, I just naturally assumed we’d shoot them at the L4 and L5 Lagrange points. I need to check the team’s website later. Do they have any information on the walkabout orbits?
This all reminds me of that proposal a while back for slow but extremely fuel efficient “interplanetary highway” transfers that made use of Lagrange points. The idea being that, once you’re at a Lagrange point, it only takes a small application of energy to send you drifting away toward any point in the solar system you like… if you don’t mind waiting.
October 26th, 2006 at 12:31 pm
“Last night as I write this” …?
Nice post, though.
October 26th, 2006 at 12:32 pm
I wrote this today, but it happened last night.
October 26th, 2006 at 1:32 pm
are these 3d images going to be something we can look at with 3d glasses?
i’m intrested in seeing what the solar system woud look like if my head were as big as the earth.
October 26th, 2006 at 2:04 pm
I wonder what they came up with first, the acronym or the mission purpose.
October 26th, 2006 at 2:56 pm
Why not Lagrange point orbits?
October 26th, 2006 at 4:09 pm
“Lats night….”
Too much coffee, Phil?
I saw the launch from my home last night.
First, we had on NASA TV, watching the countdown. After ignition, we searched the northern sky (I live in Fort Lauderdale, way south of the Cape) for signs of the rocket.
It must have been at least 2 minutes before we saw this column of flame. It looked like a really slow meteor, going in reverse. We saw booster seperation, and watched the thing moving east. It was like a bright reddish orange star. Lost the sight of it in some clouds at the horizon.
It was really neat to see this thing. Last night, people that didn’t know what was going on were making calls, trying to find out what was going on.
Shows how much one can find out on NASA’s website.
Go STEREO!
October 27th, 2006 at 6:14 am
Thomas Siefert Says:
I wonder what they came up with first, the acronym or the mission purpose.
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It happens both ways. Take MOAB, for example. When they started working on this bomb, I’m sure the project started out with the mission statement “We’re going to build the mother of all bombs”, a mocking reference to one of Saddam Husseins predictions from Operation Desert Storm. MOAB stuck, but they couldn’t officially call it “mother of all bombs”, so came up with Massive Ordnance Air Blast.
October 27th, 2006 at 8:05 am
I am under the impression that we will be able to. The images should be COOL. NASA tried to stir excitement about the mission a year ago:
October 27th, 2006 at 8:21 am
[blockquote]I am under the impression that we will be able to. The images should be COOL. NASA tried to stir excitement about the mission a year ago:[/blockquote]
Any idea if they plan to release stereoscopic images so we don’t need to fuss with 3D glasses? I’ve been very depressed that none were made available from the Mars rovers.
October 27th, 2006 at 9:07 am
This 3D image is still in the orbital plane. How does the sun look from the poles? Always wondered how such a big ball of gas keeps from collapsing when it only rotates in one plane.
Gary 7
October 27th, 2006 at 9:10 am
Of course, I know energy flow from the interior keeps it afloat(sorta), but it should be oblate, right?
GAry 7
October 27th, 2006 at 11:18 am
I got my 3D glasses off a children’s cereal box so I don’t think they’re hard to come by. I keep them in my computer desk so when the BA points us to a 3D picture I’ve got them handy!!
October 27th, 2006 at 5:36 pm
Somebody asked on the Spirit thread about where to get 3D glasses. By googling (yeah, that’s a verb now), this first site will send you the cheap paper ones for free. The nicer ones have only a minimum order of 2 @ $14.00, which isn’t bad, and after all, I’m sure you’d want two so you can cuddle up with your sweetheart and watch Mars in 3D. Or the Sun. It would be a hot date. :-/
http://www.rainbowsymphony.com/freestuff.html
October 27th, 2006 at 5:43 pm
I forgot, that site has a Mars anaglyph gallery page for those with glasses.
http://www.rainbowsymphony.com/mars_gallery/index.htm
October 27th, 2006 at 10:47 pm
I laughed at the idea of a hot date looking at 3-d mars images…
This mission is a good one. Refering back to the Katie Couric’s notion that space is a waste of money here is one with real here and now economic benefit since protecting satellites during these coronal mass ejections can have real economic benefit. As fast as a million mph is, it still gives us 93 hours to react to the turbulant sun.
And yes the orbit is neat-o!
October 29th, 2006 at 6:03 pm
Excellent article. There was never any intention to station the spacecraft at the Sun-Earth L4 or L5. The 22 deg/year drift was to get a view over a range of angles during the planned mission life. As for inter-planetary superhighways — it’s just marketing — the techniques involving lunar gravity assists used to send the spacecraft into orbit around the Sun were initially developed back in the late ’70′s and early ’80 and brought into practice with NASA’s ISEE/ICE, Wind, Genesis, and MAP missions. The Japanese also had great success with Hiten and Geotail. All before some latecomers coined the term Interplanetary Super Highway. In fact, using their techniques, you’d never find the STEREO trajectory.