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Questions tagged [earth-observation]

questions about the observation of the planet Earth from space, usually for scientific, technical, or other well-defined reasons, or about the spacecraft that do this. This tag is usually used for systematic observations, but it could also apply to a questions on specific images or photos observing something unusual requiring analysis.

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6 votes
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Hovering Carbonite! Why do these satellite videos of Earth appear to be made from a geostationary location?

The BBC News article UK satellite makes HD colour movies of Earth has led me to a series of YouTube videos as well recorded by the Carbonite-2 spacecraft built by Surrey Satellite Technology to be ...
uhoh's user avatar
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5 votes
7 answers
1k views

How can the CYGNSS spacecrafts (actually) measure ocean roughness?

The Cyclone Global Navigation Satellite System is a group of 8 smallsats which will orbit near the equator (inc=30°) and work as a constellation to take data on typhoons and hurricanes. While they are ...
uhoh's user avatar
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11 votes
2 answers
4k views

What is this huge, red, blinking light structure on Earth seen from the ISS in this video?

The video ESA video Progress launch timelapse seen from space is of course striking for many reasons. However there is a strange, blinking light structure on Earth that's quite puzzling! I've added a ...
uhoh's user avatar
  • 149k
10 votes
3 answers
1k views

Could an ISS astronaut photograph something like this 1km "Van Gogh" if they knew it was there?

At the end of December 2015, a giant "painting" made of 4 million color-sorted recycled bottles was put on display in Keelung, Taiwan. The Indian Express says it's 53 hectares, which is 530,000 square ...
uhoh's user avatar
  • 149k
11 votes
1 answer
978 views

Star-shaped artifacts in SAR images of the "Suez Canal traffic jam seen from space"

Wikipedia's 2021 Suez Canal obstruction links to the Sentinel-1 synthetic aperture radar (SAR) image of the Traffic jam in the Gulf of Suez caused by the obstruction as seen by the Sentinel-1 ...
uhoh's user avatar
  • 149k
9 votes
1 answer
468 views

Why is the Aeolus space laser losing power so quickly?

The BBC News article Aeolus: Wind-mapping space laser is losing power says that Europe's Aeolus satellite was launched last year to gather data to improve weather forecasts, and its observations have ...
uhoh's user avatar
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49 votes
2 answers
14k views

What caused this bright light from the ground at night seen from the ISS?

The music video on the NASA Johnson YouTube channel The Sound (& Visions) of Silence shows images and video of Earth taken from the ISS by astronauts Sergey Ryazanskiy, Paolo Nespoli, and ...
uhoh's user avatar
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4 votes
3 answers
798 views

Where is the camera on the MarCo cubesat that took this "pale blue dot" type of photo of the Earth and the Moon?

Where is the camera on the MarCo cubesat that took this "pale blue dot" type of photo of the Earth and the Moon? Is there an official NASA web site for photos from the MarCo cube sats? This one is ...
uhoh's user avatar
  • 149k
2 votes
1 answer
396 views

Suppose I wanted to compare TLEs to actual LEO satellite positions, what data is available? From which may it be easiest to extract X, Y, Z, T points?

Under @RyanC's answer to How can I plot satellite's trajectory from three different TLEs to detect any deviation on path with time? I wrote: I think that SGP4 + TLEs is so popular because the TLEs ...
uhoh's user avatar
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33 votes
7 answers
5k views

Is it possible to see animals from space?

Will satellite imagery be able to see the backs of big animals such as lions, tigers, elephants, horses or zebras from space when they venture out in the open? I've not been able to find satellite ...
Nederealm's user avatar
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19 votes
3 answers
6k views

Minimum number of satellites to image the entirety of Earth's surface at all times

The simplest solution would be a tetrahedron, but as the satellites all need to orbit in circles, it seems this configuration would only guarantee full coverage at one time. For simplicity, there's ...
Guillochon's user avatar
14 votes
4 answers
8k views

How many photographs are there of the whole Earth?

Most of the representations of the Earth from space that one sees are inventions, meant to clearly show the things people most want to see - the outlines of the continents, instead of mostly clouds as ...
kim holder's user avatar
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8 votes
2 answers
638 views

How were video tape recorders adapted to work in orbit in 1962?

Livescience's Satellite spies gigantic 'fuzzball' clouds spreading near Australia coast says: Actinoform clouds were first captured by NASA’s Television Infrared Observation Satellite V in 1962, but ...
uhoh's user avatar
  • 149k
5 votes
1 answer
441 views

How many (presumably friendly) lasers are being shot at us from space? (pew! pew!)

Example: at first they could not decide which of the green laser-shooting satellites was responsible! Too many to choose from? See Science Alert's February 9, 2023, Ominous Green Lasers Shot Over ...
uhoh's user avatar
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6 votes
1 answer
1k views

Has an astronaut ever seen pixies, ELVEs, sprites or blue jets (without a camera)?

The NASA Science video ScienceCasts: A Display of Lights Above the Storm shows several examples of Transient Luminous Events (TLEs) (Upper Atmospheric Lightning) being filmed by high-sensitivity ...
uhoh's user avatar
  • 149k
6 votes
1 answer
486 views

Why didn't SpaceX see that geomagnetic storm coming? Was this a fluke or could this happen more frequently in the future? (R.I.P. 40 lost starlinks)

Ars Technica's SpaceX loses up to 40 satellites to geomagnetic storm after Starlink launch explains that a geomagnetic storm heated Earth's upper atmosphere (circa 200 km) so much that the aerodynamic ...
uhoh's user avatar
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70 votes
4 answers
11k views

Why did it take so long to notice that the ozone layer had holes in it? Which satellite provided the data?

Wikipedia says: The discovery of the annual depletion of ozone above the Antarctic was first announced by Joe Farman, Brian Gardiner and Jonathan Shanklin, in a paper which appeared in Nature on May ...
uhoh's user avatar
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33 votes
2 answers
8k views

Has anyone in space seen or photographed a simple laser pointer from Earth?

In the question How to make a green LED as visually bright as a 0 magnitude star? I worked out that a 100 mA green LED with a 10° half-angle 18 kilometers away would be as bright as a 0th magnitude ...
uhoh's user avatar
  • 149k
12 votes
2 answers
3k views

Which high-resolution Earth-facing satellites transmit data to the public in realtime?

Some NASA satellites such as LASCO transmit images which are viewable by the public in real time. Are there any high-resolution Earth-facing satellites that also are viewable by the public in real ...
dotancohen's user avatar
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10 votes
4 answers
687 views

Single-shot Blue Marble pictures

I was quite surprised to read in today's Earth Observatory Picture of the Day that the DSCOVR spacecraft, currently en route to the $L_1$ Lagrange point, will be the first spacecraft able to see the ...
E.P.'s user avatar
  • 1,254
7 votes
0 answers
330 views

Have LAGEOS' germanium corner cube reflectors ever been used?

When I was writing this answer about the LAGEOS satellites, I notices that four of the over four hundred corner reflectors are made of optical germanium rather than fused silica. Fused silica (FS) ...
uhoh's user avatar
  • 149k
7 votes
0 answers
98 views

Does NOAA still plan to deploy all twelve Cosmic-2 GPS radio occultation satellites?

In the 2014 Space News interview of Jim Bridenstine (now NASA administrator, then member of the US house of representatives for Oklahoma) Q&A With Rep. Jim Bridenstine (R-Okla.) appears: Space ...
uhoh's user avatar
  • 149k
7 votes
2 answers
363 views

If all Starlink satellites had phone tier cameras & simple scopes, could images processed by their super-resolution imaging network be competitive?

I was wondering; if all Starlink satellites had high-end cellphone quality cameras modules on simple telescopes, could the resulting images be combined and processed in such a way that a super-...
AggroFrizzy's user avatar
5 votes
1 answer
756 views

How can I calculate the Characteristic Energy to Sun-Earth L1?

Alternatively, does anyone know it? I'm asking in regards to the upcoming DSCOVR (Deep Space Climate Observatory) mission scheduled to launch aboard a Falcon 9 v1.1 rocket in January 2015. DSCOVR is ...
marked-down's user avatar
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4 votes
3 answers
272 views

Why can Amazônia-1 observe the Amazon "every day or two" while Landsat takes 16 days between observations? Is "orbital magic" at play here?

The news item in Science Brazil’s first homemade satellite will put an extra eye on dwindling Amazon forests says: Right now, Brazil’s Amazon monitoring program relies on flyovers from the U.S. ...
uhoh's user avatar
  • 149k
4 votes
1 answer
587 views

Is Earth's "pear shape" mostly J₃?

@OrganicMarble's answer to 1959 Peanuts cartoon about the Fischer ellipsoid (Earth is “pear-shaped”)? finally let me see the cartoon that Mathematician, Engineer and Geoscientist Irene Fischer wrote ...
uhoh's user avatar
  • 149k
3 votes
1 answer
614 views

Have any Soviet-era astronauts reported seeing Earth's aurora or related luminescent atmospheric effects?

Earth's aurora and related luminescent atmospheric effects are generally quite dim, and mostly but not always located in the general area of Earth's magnetic poles. That means to be seen easily by eye ...
uhoh's user avatar
  • 149k
3 votes
0 answers
276 views

Are there ANY verified satellite images of visible light coherent backscattering from Earth?

Coherent backscattering is an optical phenomenon which is a bit complicated and as far as I know is pretty difficult to demonstrate in visible white light images. Image below from here. According to ...
uhoh's user avatar
  • 149k
2 votes
1 answer
443 views

Why do the solar panels on the seven Sentinel configurations look so completely different from each other?

I understant that these six different Earth-observing satellite platforms measure and image Earth data differenty, but there is just such a wide variety of different ways to build solar panels and ...
uhoh's user avatar
  • 149k
1 vote
2 answers
179 views

Which spacecraft can see plants "glow" during photosynthesis during the day, and what wavelength does it use?

This comment reminded me that I once read something about an Earth observation satellite that has a sophisticated optical system (possibly a camera) that it tuned to a very narrow range of wavelengths ...
uhoh's user avatar
  • 149k
1 vote
1 answer
148 views

What optical design is used by the GEDI's receiving telescope and how is the secondary held in place?

GEDI is a sophisticated LIDAR instrument now on its way to the ISS. Once installed, it will use powerful laser pulses (10 mJ, 242 Hz) from several lasers to map height in 3D, collecting multiple ...
uhoh's user avatar
  • 149k
23 votes
3 answers
4k views

Could a spy satellite in orbit be recommissioned to do astronomy?

Since the National Reconnaissance Office offered NASA a left-over Hubble sized mirror that might be used for the WFIRST space telescope, I wonder if the NRO has satellites in operation that could do ...
LocalFluff's user avatar
20 votes
2 answers
4k views

What is the name of the area on Earth which can be observed from a satellite?

The following image shows Earth and the trajectory of the ISS. A green line indicates which part of the earth can be observed from the ISS simultaneously. What is the name of this line or this area?
rul30's user avatar
  • 397
17 votes
2 answers
2k views

What is the highest frequency at which Earth is, or has been, observed from space?

Earth observation from space occurs throughout the electromagnetic spectrum. With my meteorological bias, I until recently believed it wasn't at frequencies higher than UV, but the X-Ray detector ...
gerrit's user avatar
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14 votes
4 answers
3k views

Do Starlink satellites have cameras?

Obviously, Starlink satellites are equipped with sensors for attitude and location detection (like a star tracker or sun tracker) but I'm wondering if they have with any direct Earth observation ...
Dragongeek's user avatar
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9 votes
2 answers
538 views

Can ISS astronauts see the lava from the Kilauea volcano at night?

The google news said "Lava from the Kilauea volcano can be seen from space" but it just links to the YouTube video of the same name. The screen shot of the video below shows a small ESA credit at the ...
uhoh's user avatar
  • 149k
5 votes
1 answer
1k views

what is revisit rate

I want to understand what the revisit rate is. If the payload is required to make the revisit rate of 5 hours. The orbit is LEO (altitude less than 2000 kms). What does this mean? Revisit time - the ...
geetha's user avatar
  • 251
5 votes
2 answers
247 views

Is it possible to deliver enough LEO satellites with one launch to substitute for one in GEO?

Rough estimates shows that having around one hundred satellites would be enough to observe a single spot on Earth continuously and via peer to peer communication deliver that information to an earth-...
Anbu Agarwal's user avatar
4 votes
1 answer
263 views

Why do the LAGEOS' satellites have four germanium corner cube reflectors out of over 400?

When I was writing this answer about the LAGEOS satellites, I noticed that only four of the over four hundred corner reflectors are made of optical germanium rather than fused silica. Fused silica (...
uhoh's user avatar
  • 149k
4 votes
2 answers
173 views

Orbits that allows observation of a polar region

If a mission is only interested in a single polar region of a planet, what kind of orbit would be most fitted for the satellite. The first things that comes to mind is a polar orbit, but then it ...
PaoloH's user avatar
  • 237
4 votes
1 answer
476 views

How exactly does atomic oxygen cause problems for spacecraft in VLEO?

In very low Earth orbit there are (at least) two problems; aerodynamic drag, and atomic oxygen (O rather than O2). Drag can be compensated with a low thrust from an ion engine. Question: But what ...
uhoh's user avatar
  • 149k
4 votes
1 answer
104 views

Why will it take a couple of weeks to complete CRYOSAT 2's orbit raising of a few hundred meters?

The BBC's Esa and Nasa line up satellites to measure Antarctic sea-ice says: Authorisation was given on Tuesday for Europe's Cryosat-2 spacecraft to raise its orbit by just under one kilometre. This ...
uhoh's user avatar
  • 149k
3 votes
2 answers
795 views

Satellite Revisit Time Analysis

I am currently making up my mind about revisit analysis. I am searching for clever algorithms to implement this in Matlab. I want to define targets on Earth surface and get the revisit times for each ...
af_ab's user avatar
  • 101
3 votes
0 answers
90 views

Given 10W and a 100 m^2 target to look for from LEO, which can search a larger area; SAR or LIDAR? (back of spherical cow-shaped envelope question)

Background For the project discussed in Space based active optical sensors for maritime surveillance the concern seems to be that SAR is off the table because a low inclination orbit is in eclipse ...
uhoh's user avatar
  • 149k
3 votes
2 answers
413 views

Has "parasitic radar" ever been used in space?

Synthetic aperture radar or SAR is becoming a hot field of Earth observation of both natural and human activity. It is very power hungry as the beam needs to deliver sufficient power over each square ...
uhoh's user avatar
  • 149k
3 votes
2 answers
368 views

How does a spacecraft like Worldview-3 manage 29 different spectral bands? One giant filter wheel, or...?

@Jack's answer mentions 29 separate spectral bands for the Worldview-3 satellite, and that these are implemented using filters. Is there one giant 29+ position filter wheel incorporated into a single ...
uhoh's user avatar
  • 149k
2 votes
1 answer
144 views

Roughly what fractions of the time did Skylab spend in Earth-oriented and Sun-oriented attitudes?

The Introduction section of NASA Technical Memo TM-X-64628 Angular momentum desaturation for Skylab using gravity gradient torques begins: The Skylab Apollo Telescope Mount (ATM) experiments require ...
uhoh's user avatar
  • 149k
2 votes
1 answer
203 views

Why was Voskhod 1 at an inclination of 64.7° degrees while Salyut 6 launched from the same latitude was at 51.7°?

This answer to Have any Soviet-era astronauts reported seeing Earth's aurora or related luminescent atmospheric effects? mentions sightings from both Salyut 6 and Voskhod 1. While Salyut 6 orbited for ...
uhoh's user avatar
  • 149k
2 votes
1 answer
136 views

What routinely happened in the TIROS control center? Was anything controlled there?

Question: What actually happened in the TIROS control center at Goddard Space Flight Center, Greenbelt, Maryland? Did they receive and print out satellite images in this room? If so, how? Did they ...
uhoh's user avatar
  • 149k
2 votes
2 answers
1k views

Can we expect shots from Starman that include the Earth and Moon together?

Just as the question asks. Will the Roadster get anywhere near, or be in any planned position to capture images of the Earth and Moon in the same field of view? A sort of "family photo" :)
coblr's user avatar
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