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33

That's a spare part - a spare Space to Ground Antenna dish for the Ku band. It's mounted on an External Stowage Platform. It was brought up on STS-127. From the STS-127 Press Kit Mission Objectives (p 17) (emphasis mine): Install Integrated Cargo Carrier (ICC) to Payload Orbital Replacement Unit Accommodation (POA) Remove and replace six Port ...


27

You probably mean RapidScat. It is a microwave scatterometer that measures near-surface wind speed and direction. Here's RapidScat in action, installed on Columbus module's External Payloads Facility (CEPF), as seen from one of ISS external cams:                   &...


21

Yes, an evolutionary designed antenna was flown on ST5 mission with success. From this NASA paper: In total, it took less than one month to modify our software and evolve this second antenna design, for which compliancy with mission requirements was confirmed by testing in an anechoic test chamber at NASA Goddard Space Flight Center. On March 22, 2006 the ...


16

Sputnik was the first satellite. It was set up before we had an understanding of how difficult it would be to maintain a satellite's position, and in fact was a very simple system overall. The 4 antennas gives an omnidirectional broadcast pattern. The simplest form of an antenna, a dipole, has two beams going in opposite directions. It's beam pattern looks ...


14

I think @PearsonArtPhoto 's answer misses several major points. From http://www.cs.mcgill.ca/~rwest/link-suggestion/wpcd_2008-09_augmented/wp/s/Sputnik_1.htm The satellite carried two antennas designed by the Antenna Laboratory of OKB-1 led by M.V.Krayushkin. Each antenna was made up of two whip-like parts: 2.4 and 2.9 meters (7.9 and 9.5 ft) in length, ...


11

It appears to match the "X band antenna" on this diagram: (Taken from https://directory.eoportal.org/web/eoportal/satellite-missions/c-missions/copernicus-sentinel-3 -- But they credit ESA for that image) It also matches the general style of at least one example antenna found in a google search for X-band antenna. (X Band Isoflux antenna from https://...


10

To complement: The SGANT is the antenna that transmits high data rate signals, including many up/down video feeds, from/to the ISS. There is a total of 3 antennas: 2 at the end of booms on the Z1 trust, and the spare that you have identified. The active SGANT transmits/receives data by pointing to a TDRS satellite continuously for a portion of an orbit (~120 ...


10

Yes, the whole strut-and-lens system was a giant balloon. There is good information in this paper. Folded up and deflated, it looked like this. This fit into a box mounted on the side of the SPARTAN-201 carrier bus. The "balloon" was made of Mylar. The basic deployment scheme for IAE was based on ejecting the stowed reflector structure, as a package, ...


10

We're working on it. You do need a little telescope on the spacecraft to serve as the antenna. You can have two-way laser communications. It may in fact be essential to achieve the required pointing accuracy. There are many modulation schemes -- that's not an issue. Pulse position modulation is a front runner. The upside is much higher data rates with ...


9

There is enough hydrazine to last beyond the end of the mission, about 25% of total tank volume is still available. From Descanso volume 4, you can see enough hydrazine for attitude control is available to last until 2040/2048: As in all communications around the end of life for Voyager operations, this lifetime estimate considers the mission to end when ...


8

Exact radiation patterns and gain (you're probably not asking about signal strength since that depends on distance which isn't constant) will vary across all the different GNSS contellations, even individual generations / blocks of same systems, but for a fairly detailed analysis of GPS blocks, you can refer to e.g. GPS Space Service Volume: Ensuring ...


7

This is a rotating antenna, part of the Kurs docking system on Soyuz and Progress spacecraft See e.g. This video of a docking


7

Spacecraft use a star tracker to find their orientation (attitude). Here's a random example: Dimensions and Mass: Camera 120 by 120 by 33 mm, 1.0 kg (note: optics protrude 58 mm inside baffle) Processor 245 by 165 by 29 mm, 1.2 kg Baffle Examples: 30º (sun exclusion), Ø234 by 346 mm, 800 g 45º (sun exclusion), Ø167 by 203 mm, 470 g 60º (...


7

After reading @ Saiboogu's answer explaining what this is, I found some additional helpful information. This is an isoflux antenna, designed to provide an approximately constant flux of broadcast signal over the useful transmission footprint on the Earth, from the nadir out to a maximum cone angle of 60 degrees from the nadir as seen by the spacecraft. ...


6

Phased arrays have mathematical limits, so you may still need to have gimbals or orient the array. In particular they suffer from decreased gain off-boresight. The more elements to the antenna, the tighter the beam, but the worse the off-boresight issues. NASA has studied these issues, and there are solutions (such as having multiple arrays). In the ...


6

To address the last part of your question ".. or are they already taking over" phased arrays have been used in commercial communications and remote sensing satellites for a while already though I don't think they are "taking over" as such. These examples aren't the interplanetary use you have suggested but they do serve to demonstrate that the technology ...


6

This answer is based on a book called "The Design and Engineering of Curiosity" https://doi.org/10.1007/978-3-319-68146-7 On chapter 6 it is mention that The Hazcams and Navcams are flight spares or build-to-print copies of the engineering cameras of the same names on the Mars Exploration Rovers; this not only saved money in hardware, but made it ...


6

This is an interesting question! There are (at least) two communications issues to consider. One is signal strength as the question asks about, the other is latency or delay. But the tl;dr is that this won't work using standard WiFi or cellular data equipment because the antenna would have to be kilometer sized, and the delays are incompatible with the ...


6

Those are spiral antennas. Spiral antennas belong to the class of frequency independent antennas which operate over a wide range of frequencies. Polarization, radiation pattern and impedance of such antennas remain unchanged over large bandwidth.[3] ... Spiral antennas are reduced size antennas with its windings making it an extremely small structure. ...


6

They appear to be associated with a plasma wave experiment called Obstanovka (lower left of this picture, in red). Source is this presentation. More info on the experiment, and this image, here. (This web page is an interesting mash-up of English, Japanese, and Russian!) Bonus: I believe the video was shot through the 16-inch Service Module window 9, the ...


6

Signals are not repeated, but instead coded in a special way that allows to reconstruct the original data on the receiver side in presence of noise/errors. It is called forward error correction. FEC schemes are more efficient than just blindly transmitting the same data twice (though they of course increase the total amount of data that has to be ...


6

It's the electrical equivalent of a Fresnel mirror; the reflective cousin of a Fresnel lens. Each of the little square patterns is actually a little passive circuit that reflects the incident microwaves with a different phase shift. It is called a Reflectarray antenna. You can read more about it in this Researchgate paper A Deployable High-Gain Antenna ...


5

That is the "Kurs system 2AO" antenna on a Soyuz. It measures line-of-sight heading and pitch angles. Sources Modelling of Soyuz Docking and Radar Systems for Implementation in the IRS Simulator Obsolete NASA page on Kurs Personal notes


5

I can't speak specifically for the tech on SES-10 since I didn't work with that (yet), but on the previous GEO spacecraft I've worked on, the idea is to alter the radiation pattern. Specifically, heritage antennas on GEO bird are not smooth like you would usually get on a home dish antenna. By adding "bumps" into the antenna, the signal can be directed one ...


5

There are some papers about antenna design on Gaia, and this one by EADS CASA Espacio has many details on GAIA Antenna: http://ieeexplore.ieee.org/document/5505027/ Allica, J. C., Alonso, E., Amado, M., Bazán, A., Casares, F., de Witte, E., ... & Serrano, J. L. (2010, April). "Architecture of GAIA satellite phased array antenna" - 2010 Proceedings of ...


5

I think your question boils down to weather or not people associated with the design, fabrication or operation of Inmarsat 2F1 refer to the L-band transmit antenna specifically as a "phased array". I think we can all agree that the phases are specified and managed. Further, based on the article below (and others), I think they are designed to be fixed once ...


5

I haven't made an exhaustive survey, but I checked the major outer-planets missions. The Galileo spacecraft was designed with a 4.6-meter diameter high-gain folding dish antenna which was supposed to deploy somewhat like a folding umbrella; however, it jammed and didn't deploy fully, and the mission had to rely on a smaller antenna. I believe this is the ...


5

The single largest commercial satellite reflector (18m) is on Terrestar-1. But Japan's ETS-VIII had two reflectors, each of which was almost as big (19m x 17m). Classified satellites are rumored to have had larger reflectors. This article claims 77 meters for a signal intelligence satellite it calls MAGNUM. This article claims 100 meters. To my ...


4

The constantly rotating antenna is a good sign that the AE-35 unit is working correctly, and that the ISS astronauts should therefore avoid any unnecessary EVAs regardless of the advice of their onboard computer.


4

It's stock footage. Here's the source: https://www.shutterstock.com/video/clip-3547922-stock-footage-satellite.html?src=search/j9qjEB4D-XcqsNoqfQWZrA:1:4/gg


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