*mad laughter*

Here I sit with 13 hours to prepare a presentation upon which my very degree depends. To occupy the ticks between I scan the site of Sergey Lukyanenko, whose novel Night Watch I lately bought (Who could focus continuous 'pon their task? Not I!). At least it has given some profit, for his bibliography has seeded in me a new story (no, not to copy).

Welp, back to work!

^_^

Burn Through, Burn

Ugh! I had been tappin' away at a post on NASA's TPF (that's Terrestrial Planet Finder, for - can you guess?) and now a careless delete tab has et it. So, hum, let's do a quick reiteration instead, top o' my head.

So indeed, we have the Terrestrial Planet Finder, a mission in development by NASA as part of its Origins program. The goal is to find and to study earth-like planets within 60 light years (18.4 parsecs). Will be looking at F, G and K type stars in particular.

Originally being considered were four projects within the scope of the TPF, since reduced to two. Those two being what they call the moderate sized coronagraph (TPF-C, 4 by 6 metres, compare with the 2.4m Hubble scope) and a formation-flying interferometer (TPF-I, as opposed to one with its compnents held in place by struts).

Talking about TPF-I first. It is intended to consist of a number of component telescopes - at no point have I seen any information describing exactly how many - three to four metres in diameter (again compare with the 2.4 metre Hubble, though perhaps there is another, better comparison to make. If there is I do not know it) and, as mentioned, free flying, so they will need to correct any drift in relative position with little rocket engines. And they will have to. An interferometer works by combining light picked up by two (or more) components to create a single overall image. I do believe the components need to be kept in place to within half a wavelength in order for the whole dealie to work. In this case, because TPF-I will operate in the mid infrared, these telescopes need to be positioned to within 5 micrometres. I wonder if that was any part of the reason for TPF-I being an IR mission and TPF-C going visible. Not sure what else there is to say except, being that it operates in the infrared TPF-I needs a cooling system to prevent heat glow from the intruments themselves spoiling the image, apparently. And though I have not seen it stated outright I have the impression it is to be placed somewhere far enough away that Earth won't get in the way as it does for Hubble. Oh, and that the thing is expected to solve the contrast problem by being a nulling interferometer, which, far as I can understand it right now, I think means that signals direct from the star are canceled out by being combined destructively when the overall image is put together, while the planet(s?) gets to shine through constructively. Ah, this is what I get for being three years past optics and failing EM twice - better luck next semester!

Past time for a new paragraph, don't you think, dear reader? Well, this mission is in early stages yet, not even testing of components. Aimed to launch sometime before 2020, but probably after 2016 as that is when TPF-C is meant to launch and TPF-C is meant to go first.

And what of TPF-C? I'm afraid all I can find right now is the mirror size, hoped ofr launch year and visible lightness of it. And that a coronagraph is basically a screen for blotting out starlight to see dimmer objects which would be otherwise obscured.

Okay, one final thing of this mission. According to the project's newsletter their funding for the 2007 to 2011 fiscal years is zero. And according to other sources what we have to thank for that is Bush's declaration of intent to return humans to the Moon and  beyond along with the providing of very little extra money to actually accomplish the deed, forcing the cutting or sidelining of other programs. Well, any regular reader of Bad Astronomy will be familiar with this.

Kay, next! (Questions, though welcome as always, I 'spect will come too late for the answering to do anything for my marks. Still helpful and still fun hough)

Darwin, what's that?

It is a planet-finding scope being built by the ESA (that'd be the European Space Agency [trying to err on the side of too much info rather than too little, at least when I feel like providing it]), that's what. Intended to launch in 2015 this one will consist of a flotilla of three craft/scopes (oh, plus one other for communications). Like TPF-I, Darwin will operate in the infrared and each of its telescopes will be at three metres in diameter. This scope is going to be placed in orbit at L₂, 1.5 million kilometres from Earth. Will likely excise starlight as a nulling interferometer.

Well, what else is there to be said? I feel that, having not slept last night, I must be missing important things but could not say what. I recommend checking out the ESA's site for Darwin, very clear and informative.

SIM - Blah

So now, so now. The mission's page says it is ahead of schedule. Like most of the past few missions I have mentioned SIM is an interferometry mission, but this one's goal is not to detect the light of other worlds directly. SIM is an astrometry mission, it will be measuring the positions of nearby stars and seeking the wobble induced by planetary companionship. Among some of its nearer targets SIM might detect worlds as small as twice Earth's mass.

This observatory goes into Earth-trailing orbit, drifting out over the course of several years (5.5) to its placement position 95 million km away. And, surprise surprise! SIM will operate in visual light. Its apertures (for all three scopes) will be only 0.3m, mounted on a 9m baseline.

HAHAHAHAHA! Now I get to toss aside this instrumentation and move to more interesting matters. Also to transform this into a presentation with illustrations and effects and all. 2 hours.

Ehdithe: SIM is supposed to launch sometime before 2016.

Their list of what it could find (minimum size constrained by distance) -

• Earth mass around 6 stars
• Twice Earth mass aruond 30 stars
• 3.2 Earth mass planets around 120 stars
• Neptune massed planets around 2,000 stars (Wikipedia says Neptune is 17 times as massive as Oit)
  

It actually says size but I think they mean mass, though I could of course be wrong