Plans for Lunar telescope

[Royston]

As part of the Decadal Survey, which marks plans for future research in astromomy and astrophysics (every ten years, as the name suggests) a lunar telescope is one of the ideas put forward, to study the 'Dark Ages' of our universe, please see the sciencedaily article below...

 

from the article

 

A team of scientists and engineers led by the Naval Research Laboratory (NRL) will study how to design a telescope on the Moon for peering into the last unexplored epoch in the Universe's history. NASA has announced that it will sponsor a series of studies focusing on next-generation space missions for astronomy

 

Although the night sky is filled with stars, these stars did not form instantaneously after the Big Bang. There was an interval, now called the "Dark Ages," in which the Universe was unlit by any star.

 

The most abundant element in the Universe, and the raw material from which stars, planets, and people are formed, is hydrogen. Fortunately, the hydrogen atom can produce a signal in the radio-wavelength part of the spectrum, at 21 cm; a wavelength far longer than what the human eye can detect. If these first signals from hydrogen atoms in the Dark Ages can be detected, astronomers can essentially probe how the first stars, the first galaxies, and ultimately the modern Universe evolved.

 

EDIT: May help if I provided a link...

 

http://www.sciencedaily.com/releases/2008/03/080311124548.htm

[Mr Skeptic]

But why put the telescope on the moon? Why not in permanent orbit behind the moon?

[JohnB]

I think because a telescope on farside is constantly sheilded from Earth's interference, but one in orbit is not.

 

Besides, it's another good reason for a moonbase.

[D H]

But why put the telescope on the moon? Why not in permanent orbit behind the moon?

 

1. You can't, if you are talking about the equivalent of a geostationary orbit around the moon. Such an orbit would be well outside the Moon's Hill sphere.
    
    
   
2. If you are talking instead about the Earth-Moon L2 point, there's a big problem with regard to communications: the Moon is in the way. Moreover, the collinear Lagrange points are unstable. There is no such thing as a permanent orbit. Because the Earth:Moon mass ratio is 81:1, halo orbits about the Earth-Moon L1 and L2 points require quite a bit of stationkeeping fuel. A better bet would be the Sun-Earth L2 point. The huge Sun:Earth mass ratio drastically reduces Sun-Earth L2 stationkeeping requirements compared to the collinear Earth-Moon Lagrange points. The WMAP observatory is at the Sun-Earth L2 point; the James Webb telescope will also be located there.
    
    
   
3. Ground-based telescope have a huge advantage over space-based telescopes: platform stability. Space-based telescopes have a huge advantage over Earth-based telescopes: no atmosphere. A Moon-based telescope offers both advantages. The Moon's slow rotation rate makes things even better. Astronomers have wanted a Moon-based telescope for a long, long time.

[YT2095]

I think because a telescope on farside is constantly sheilded from Earth's interference, but one in orbit is not.

 

this would include Radio noise too, IIRC when the astronauts did an orbit around the dark side there was a radio blackout, this effect could be Very exploitable and also save a Load of money and fuel not having to carry up filters and discriminators up there.

although it Might be a good idea to have an orbital sat to act as a repeater for the data gained there.

it`s all well and good obtaining plenty of good data, but you still have to get it Out somehow

[JohnB]

this would include Radio noise too, IIRC when the astronauts did an orbit around the dark side there was a radio blackout, this effect could be Very exploitable

Yep, main base on nearside and an observatory on farside. I like the idea of constructing the observatory in Daedalus myself, the high crater walls would be an added bonus.

 

Comsat the data to main, and from there down to Earth.

[YT2095]

I like the idea of constructing the observatory in Daedalus myself, the high crater walls would be an added bonus.

 

True, not only for Light, but also micro-meteor protection for a range of incident angles.

I wonder if the low grav could be exploited in a way that would allow the construction of repeater mast(s), a little taller than would practical here on Earth to get over the horizon?

[insane_alien]

yeah, repeater masts could be built taller on the moon but you have to remember the horizon will be closer due to curvature of the moons surface being greater. couple of satellites would be an easier and cheaper option.

[D H]

yeah, repeater masts could be built taller on the moon but you have to remember the horizon will be closer due to curvature of the moons surface being greater. couple of satellites would be an easier and cheaper option.

Communication satellites like those orbiting the Earth are not an option for the Moon. A lunar satellite with a one month period is well beyond the Moon's Hill sphere; the orbit can't exist. A communications satellite in a halo orbit about the Earth-Moon L2 point is a possibility, but fuel consumption for stationkeeping is an issue here.

[insane_alien]

yes i know that, but they could be at a lower orbit and have more of them. it can still work.

[YT2095]

I initially considered a sat myself (post #5) but after consideration I reckon Masts will be better.

 

Infinitely more servicable, indefinite service life, can be used for Other applications as well, and cheaper in the Long term.

[JohnB]

I can't agree.

 

If we built a nearside base and a farside oservatory then we would be going back to the moon in force. Survey/Mining expeditions will often be out of LOS of the towers and therefore can't call for help.

 

Comsats are the only way to cover the entire Lunar surface in a way that allows for exploration and mining.

 

The moon is the logical place to extract and refine the minerals for the next generation of spacecraft so we will be exploring and mining. We all know the drill, solar power, rail guns the whole bit. It's cheaper to ship the equipment to the moon than to lift the components out of Earth's gravity well so we might as well plan for large scale exploration and extraction from the word go.