Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. Listen now.
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When discussing radio antennae, radio astronomers usually describe things in terms of temperatures. We can convert between power and temperature simply by multiplying (or dividing) by Boltzmann's Constant: $P=k_BT$. We define the antenna's System Temperature, $T_{sys}$, as the sum of all the temperature contributing factors. The most important contributor ...


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Using current technology (and by that I mean experiments and telescopes that are available now) we would probably be unable to detect life on Earth even if observed from a distance of a few light years. A "blind" search could look for radio signatures and of course this is what SETI has been doing. If we are talking about detecting "Earth-like" signals, ...


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No. The landing time is determined by the interplanetary trajectory, largely fixed by launch energy constraints, and then by the landing site location, mainly the longitude. This paper identifies the landing site selection criteria, which were almost entirely about the safety of the landing. And appropriately so for an EDL demonstration mission. The landing ...


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That antenna is a Cassegrain horn (or 'casshorn'). This is an evolution of the earlier horn-reflector antenna (paper that describes the design), where a horn radiates into a parabolic surface: The Cassegrain horn reduces the antenna size (long distance between the horn and parabolic dish) by introducing a hyperbolic reflector: The feed is now at position ...


6

Transportation of data between observatories was done via magnetic tape using a standard or common format. At least this was the case for the Westerbork Synthesis Radio Telescope and the observatories in Europe that it interacted with in the 1970s, though I imagine that was a pretty common practice. Tape was a good format for storage and transport of large ...


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Because the dish isn't a black body. At RF it has a very low emissivity, hence the name "reflector".


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The way these images are usually done are by imaging the object for an extended period of time, and seeing how they are different. This can be done either with radar or passive systems like visible and infrared light. Here is a paper detailing how it is done, but basically they incrementally rotate the object in simulation around and seeing what matches, ...


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Supplemental answer: Three sites in Australia were used to communicate with Apollo. Tidbinbilla (now called Canberra DSCC) Designed and continues to be used for tracking and communications of deep-space probes by NASA's Jet Propulsion Laboratory. One of three locations of the Deep Space Network (DSN). Located in the Australian Capital Territory, which ...


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The International Space Station, by far. The mass of the station varies with time, but it's around 420 tons It was constructed over the course of about 13 years, although it is still being tweaked today.


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Planck → Rayleigh-Jeans: I'm not talking about the infrared radiation from the telescope. That is probably removed by managing line-of-sight within the cryogenic waveguide, or a low-temperature window or both. I'm talking about the circa 300K radio emission of the 70 meter primary and 8 meter secondary. The key to answering this question is to have some ...


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I've only been able to find one reference to joint observations thus far: Juno produces five pole-to-pole latitudinal maps of microwave opacity as a function of altitude to depths greater than 100 bars (Figure 2). The independent swaths at different longitudes provide the ability to understand large scale features such as the Great Red Spot. The 0.1%...


3

Naive maybe, but your Google Maps picture appears to be correct. This page goes into the history of the Parkes Telescope. It's clear that it has never been moved and is at the Visitor Center location on the Google map. The 1965 map on this page shows the location of Honeysuckle Creek to be due south of Canberra, as shown on your Google map. So the ...


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A brief search led me to the conference proceedings for the "Life in the Universe" conference held at Ames Research Centre in 1979 (yes, this is old, but serves as a good baseline from which to begin). The paper "Eavesdropping Mode and Radio Leakage from Earth" notes that early warning systems for ballistic missiles beam intense radio signals that could be ...


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The Earth-Moon L2 is located about 1.16 times as far from the Earth as the centre of the Moon (wikipedia, so the Earth is about 7 times as from L2 as the Moon is. Since the Earth is less than 7 times the Moon's diameter the Moon would protect a telescope at L2 (or in any small halo orbit around it) from all radio noise directly from the Earth and from LEO. ...


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The MERLIN array in the UK used dedicated microwave links for several decades: Lovell, Bernard (1985). The Jodrell Bank Telescopes. Oxford University Press. ISBN 0-19-858178-5. Nature volume 288, pages 64–66 (06 November 1980) The Jodrell Bank radio-linked interferometer network (paywalled) From MERLIN biennial introduction: MERLIN is an array of six ...


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Supplemental answer: This answer and comments below it show that even in 2018 people are carrying boxes of hard drives around on airplanes to do VLBI (VERY Long Baseline Interferometry) interferometry. Here I've highlighted "very" because the baseline is the size of our planet in the case of the Event Horizon Telescope. Computer World: Massive telescope ...


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I'll add a little bit to Hobbes' excellent answer and detective work. I looked up a physical copy of the book linked there; Practical Conic Sections: The Geometrical Properties of Ellipses, Parabolas and Hyperbolas by J. W. Downs, Dover, NY, 1993 and found it a short but incredibly interesting and informative little book, if you like reading about conic ...


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InSight used an UHF transmitter to transmit a tone beacon during EDL: At the top of each of InSight’s legs is a trigger sensor; when the surface pushes up the leg and hits the trigger, it shuts off the lander’s retrorockets. It also sends out two signals that touchdown has been achieved: a “tone beacon” through its UHF antenna and a “beep” through its X-...


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The basics: When they are not commu­nicating with spacecraft, the DSN antennas are used for radio astronomy. For more than 30 years, the Deep Space Network has played a significant role in radio astronomy studies of our solar sys­tem, adding to our under­ standing of the magnetic fields and atmospheres of planets. For example, since 1972 radio ...


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Thus, if we include in the review the entire history of the space age: 1. Deep Space Network https://en.wikipedia.org/wiki/NASA_Deep_Space_Network Established October 1, 1958 Komandno-Izmeritelniy Kompleks SSSR (KIK SSSR) Established September 3, 1956 http://kik-sssr.ru https://en.wikipedia.org/wiki/Soviet_Deep_Space_Network Chinese Deep Space Network ...


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It is an NHATS object. I found it on there but first I had to select 'Use Unconstrained Settings'. The default view restricts on some parameters. DeltaV is over 10 km/s. On question over the Goldstone planning info, H=26.7 is the absolute magnitude of the object. This relates to the size and reflectivity (albedo) of the object itself and is not specific to ...


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I think the main reason can be viewed two ways: Although faint, the signal is also highly directional, coming from a single point in the sky, so it's brightness temperature is actually quite high. So long as the telescope is big enough to focus in on a very small patch of sky, the signal is louder than the noise. The thermal noise from the different parts ...


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The first precision formation flying mission is ESA's Proba-3, slated for launch in 2018. Proba-3 is ESA’s – and the world’s – first precision formation flying mission. A pair of satellites will fly together maintaining a fixed configuration as a ‘large rigid structure’ in space to prove formation flying technologies. The mission will demonstrate ...


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