Update: They launched this morning and are safely on their way...all looks good.Tomorrow is a big day for the European Space Agency as they launch two big missions on one Ariane 5 rocket. These are both important missions so there is a lot riding on a successful launch tomorrow.
The first mission is the Hershel Space Observatory. Herschel is a 3.5 meter space telescope, the largest ever launched (Hubble is a 2.4 meter telescope for reference). Herschel is not a competitor to the more famous Hubble...Herschel will observe in the far infrared (Hubble does some near infared observations). The universe looks very different in the infared. Many cool objects give off most of their light in the infrared. Distant objects. Herschel will probe the earlierst star forming regions and be able to detect where planets may currently be forming with unprecedented resolution.
To observe in the infared, you need to cool the detectors down to near absolute zero. Herschel will carry a couple thousand liters of liquid helium to coolits instruments. Herschel has a large sunshade (as you can see in the diagram) and will obrit the Sun, away from the heat of the Earth (at a point called L2 for those into orbits). Unfortunately, this limits its lifetime. It should last at least three years, but then it will warm up. We cannot service a satellite orbiting at L2, so the mission wil
l be over. There is a nice mission overview brochure on their website.
The second mission is the Planck satellite. Planck will make the most detailed observations ever of the cosmic microwave background (CMB) radiation. The CMB is left over from the big bang. A previous satellite called WMAP put a lot of of constraints on the age and makeup of the universe by measuring the CMB, but left some major questions unanswered. Placnk could shed more light on the nature of dark matter, dark energy, and the early history of the universe.
Planck has a couple of things in common with Herschel. First, it will orbit at L2 (don't worry, there's a lot of room out there so they won't collide!) Second, it will carry liquid helium to cool its instruments close to absolute zero to make its observations. Planck is scheduled for 15 months of observationsl, but you can bet they will run it until the last drop of coolant runs out.
This is a big launch with much higher stakes than usual. You can watch the streaming video here. Laucnh is scheduled for 9:12am EDT if I am subtracting correctly...good luck Planck and Herschel!Reprinted with permission from the Half-Astrophysicist Blog.
I'm glad the liftoff went smoothly. We have so much more to learn.
ReplyDeleteBopster, couple questions, “what is L2 and in three years does this scope just become another piece of ‘space junk’ hanging out there?
ReplyDeleteMr. Bopp:
ReplyDeleteI was just at the local book store. Kinda odd since most of the people that live here or near here can't read. LOL. Anyhow on the counter was this REALLY NEAT glass ball on a lighted stand with the famous "Hale Bopp Comet" inside of it. It is the 2009 limited edition made by a company named "Glass Eye Studio" They must be out of Washington State because each piece has ash from Mt. St. Helens eruption. They have it priced at $195.00 which i'm pretty certain is probably HIGH. I thought you would be interested to know about this? Perhaps it on the net?
L2 is a semi-stable orbit about 1.5 million km (~900,000 miles) from the Earth on the exactly opposite the Sun. The gravity of the Earth kind of tugs it along so it always stays (roughly) in the same place relative to the Earth. This is far enough from the Earth that you don't have to deal with thermal interference from the Earth (as long as you look the other way which they will) and keeps the satellite in pretty much constant radio contact. Since gravity does most of the work to keep the satellite there, fuel requirements are minimal. Herschel is gong to be in an orbit around this point in space (kind of odd to think of an orbit with no physical object there, but it works).
ReplyDeleteThe best info I can find is that they want to observe with it for three years, but expect the coolant to run out after four and I fully expect them to observe until it is bone dry. After that, I haven't been able to find any info. We are doing a better job of making plans for what to do with satellites in low Earth orbit (at lest vent their leftover propellant so they don't blow up and cause a lot more space debris!) but I don't know about this one. A quick search didn't turn up the answer and I don't want to dig that deeply into the ESA documents!
Thanks, Toad. I think this is the company you refer to. They are nice...what bookstore is it?
It's a Family owned shop.
ReplyDeleteTreasured Words
110 E. State St.
Mauston, WI 53948
608-847-2060
Ask for Gary. He will know me as Mr. Negative. I told him I knew someone that the Comet was named after. LOL
Toad-I do have some Mt St. Helen ash...
ReplyDeleteDrew: ASH, that makes me think of a funny. My mother-in-law died about 8 years ago and was cremated. We got a nice cardboard box of ashes from the funeral home and planned to have them placed next to her husband in Graceland. (not Elvis Graceland) in the summer. I still remember that day. I took the box out to the car and put it in the back seat, put the seat belt around it, God knows I didn't want her all over the car, and went to Racine and put it in the ground with a tiny ceremony. What i'm getting at is, maybe I should have kept a little?
ReplyDelete