[LMB] Arecibo

Marc Wilson marc.wilson at gmx.co.uk
Mon Nov 23 20:53:34 GMT 2020


On Mon, 23 Nov 2020 20:26:27 +0100, Markus Baur via Lois-Bujold
<lois-bujold at lists.herald.co.uk> wrote:

>
>Am 23.11.2020 um 19:07 schrieb WalterStuartBushell:
>>
>>
>>> On Nov 23, 2020, at 10:29 AM, Markus Baur via Lois-Bujold
>>> <lois-bujold at lists.herald.co.uk
>>> <mailto:lois-bujold at lists.herald.co.uk>> wrote:
>>>
>>> let us take the arecibo design as plubeprint and look where we can
>>> reduce mass
>>>
>>> the dish itself can be made from very lightweight aluminized foil (it
>>> does not have to deal with wind and rain) - this also means that the
>>> anchor cables for the dish can be made a lot thinner.
>>>
>>> we also might not make the cables (both for the dish and the gondola)
>>> from aluminium or steel - modern synthetics like Spectra offer a much
>>> better weight / strength ratio
>>>
>>> the receiver gondola suspended over the dish also does not have to
>>> deal with weather ..
>>>
>>> so i would not be surprised if it could be built with only 1/10 of
>>> the mass of the original
>>>
>>> total weight of the arecibo observatory seems to be around 1500 tons
>>> .. so a lunar arecibo would be around 150 tons
>>>
>>> and that is not completely out of bounds, if SpaceX gets the lunar
>>> version of the Starship to work (estimated paylaod to lunar surface
>>> aruond 40 tons .. 4 flights .. getting the resto of the necessary
>>> infrastructure (quarters for construction and maintenance crew,
>>> constructrion machinery, etc. ) up might take even more paylaod than
>>> the telescope itself
>>>
>>> servus
>>>
>>> markus
>>>
>>
>> More feasible would put it in low Earth orbit, where there is
>> radiation protection from the Earth’s magnetic field,
>> and it can scan more of the sky.
>
>yes - it can scan a lot more of the sky .. but you also get  the full
>dose of earth's radio noise .. putting the telescope on the far side of
>the moon will cut down on the noise by an absolutely HUGE amount
>
>also - it can look at one spot of the sky only at aa time .. but
>observations are planned a long time ahead - so having to wait 14 days
>to be able to see the "other side" of the sky usually is not a big burden
>
>the long planning ahead also makes the 2 to 3 second communications
>delay from / to the far side not a big problem .. only if you absolutely
>need to hold a real time conversation, and even there 2-3 seconds are
>manageable
>
>the logistics of building and maintainnig the telescope will be made
>easier in LEO yes ..
>
>the radiation however will be a lesser problem - lunar regolith is a
>nice radio shield, but also a good radiation shield (the habitat for the
>building and maintenance crew will be below the surface)
>

How about the L2 point?
--
The fact that an opinion has been widely held is no evidence whatever
that it is not utterly absurd;  indeed in view of the silliness of the majority
of mankind, a widespread belief is more likely to be foolish than sensible.
  - Bertrand Russell



More information about the Lois-Bujold mailing list