Skip to main content

Questions tagged [optical]

Questions involving optical components, such as lenses, filters, and mirrors

Filter by
Sorted by
Tagged with
0 votes
0 answers
24 views

GCRS and ICRS Frame in Optical Observations from near earth

Lets say I am trying to observe the night sky. My telescope has a pointing direction. I want to compare the RADecs of each star with another. Now I have 4 cases. My telescope is on a satellite ...
NIKITA SEHRAWAT's user avatar
0 votes
0 answers
74 views

Inserting optical elements into a ring laser gyroscope to sense all three axes

Ring laser gyroscopes (RLGs) leverage the physics of ring laser interferometers and the Sagnac effect to sense rotation in a single plane. My understanding of RLGs is that they are independent systems ...
Jonathan L.'s user avatar
1 vote
3 answers
159 views

What would be the advantages and disadvantages of a LEO Earth observation satellite, carrying both Electro optical and SAR payload be?

An Indian startup, is trying to build a multi- payload satellite having both optical and SAR sensor on the same satellite. The look angles of the these payload are quite different and it is very ...
Bharath Simha Reddy's user avatar
10 votes
2 answers
1k views

Interesting diffraction pattern on JWST composite false-color image released today (July 11) at Biden preview - how does this arise?

There was an earlier question on the diffraction pattern in the Mar 16 test image that was mainly explained by the hexagonal shape of the individual mirror segments. Today's image has similar ...
Roger Wood's user avatar
  • 3,864
8 votes
1 answer
458 views

JWST - pick-off mirrors?

In the documentation that I’ve been looking through recently, I occasionally come across references and diagrams to “pick-off” mirrors. For example, from this JWST user documentation article, there is ...
Bruce Simonson's user avatar
2 votes
0 answers
91 views

How to calculate laser link spot size

In the reseach paper " A laser link from lunar surface..." , chapter 2.1.3.: When employing, for example, 20 cm diameter apertures at the transmitter telescopes and considering a carrier ...
FrimHart64's user avatar
5 votes
1 answer
401 views

How is the maximum data rate of the Psyche mission's Deep Space Optical Communications (DSOC) system expected to scale with distance?

NASA's Mission Page Deep Space Optical Communications (DSOC) includes the following: Key DSOC technologies developed for the project include: a low-mass spacecraft disturbance isolation and pointing ...
uhoh's user avatar
  • 149k
9 votes
1 answer
735 views

Why aren't off-axis reflector telescopes more popular for space telescopes? Have there ever been any?

It seems that: The light gathering capabilities would be slightly better without the blocked aperture (clear aperture is a premium for fairing-limited space telescopes) The diffraction patterns from ...
Alonda's user avatar
  • 491
2 votes
1 answer
285 views

Are direct conversion optical receivers being looked at for future deep-space communication?

In this answer to Receiver and transmitter in RF/optic satellite communication: distance vs data rate v2 I explain that since the currently used photodiode-based photodetectors for optical ...
uhoh's user avatar
  • 149k
4 votes
2 answers
479 views

What are the reasons for the specific operating wavelengths chosen for laser communication?

I am reading the book: Kaushal, H., Jain, V.K. and Kar, S., 2017, Free space optical communication, New Delhi: Springer India. The operating wavelengths for beacon and data transmission were discussed....
Noel Miller's user avatar
0 votes
1 answer
246 views

PAT (Pointing Acquisition, and Tracking) system in lasercom

After reading some articles and posting questions 1, 2 I think, the main challenges are PAT (Pointing Acquisition, and Tracking) system and operating environment. We must put the beam onto the ...
Anna Koroleva's user avatar
4 votes
1 answer
417 views

Data rate in optical free space communication systems

Mynaric is one of the main suppliers of laser terminal for free space communication. In one of its latest publications I have read, they will increase the data rate of the last lasercom terminal up to ...
Anna Koroleva's user avatar
4 votes
1 answer
299 views

There are only a few suppliers of optical terminals: what is the reason?

I am conducting research into optical free space communication and small/nano satellites in LEO. I have found only a few companies which supply lasercom (laser communication) terminals (transmitter/...
Anna Koroleva's user avatar
0 votes
1 answer
145 views

Beacon (PAT) in optical free space communication [closed]

Nanosatellite Optical Downlink Experiment (NODE) mission has 3 "signal":downlink, beacon uplink and RF. According to a description of the mission, the high-rate downlink and beacon uplink ...
Anna Koroleva's user avatar
3 votes
0 answers
344 views

Biggest periscope camera that could fit inside a Starlink satellite; how thick are they?

If all Starlink satellites had phone tier cameras & simple scopes, could images processed by their super-resolution imaging network be competitive? is a cool question and to integrate a reasonable ...
uhoh's user avatar
  • 149k
2 votes
1 answer
176 views

Optic communication: day and night

Will launched time of a laser satellite teminal affect to transmission parameters, as data rate, power …? As I know , the main limitation of lasercom is a direct line-of-sight path exists between a ...
Adil.Kolenko's user avatar
4 votes
1 answer
147 views

Space based active optical sensors for maritime surveillance

I am designing a CubeSat. The size is yet to be decided as it is based on the sensor. The mission is maritime surveillance (illegal fishing). The payload should be capable of detecting the vessels. ...
geetha's user avatar
  • 251
1 vote
1 answer
236 views

Frequency/Spectrum regulation document for laser communication

For RF we have the frequency allocation table, where the RF spectrum is regulated. Optical has big bandwidth, there is a lot of frequency space. How do we regulate optical spectrum? I didnt find any ...
Adil.Kolenko's user avatar
1 vote
1 answer
459 views

Receiver and transmitter in RF/optic satellite communication: distance vs data rate v2

The first version of this question is here. I have read the article "Optical communications work best over relatively short distances in space." by Toyoshima, M., Leeb, W., Kunimori, H. and ...
Adil.Kolenko's user avatar
2 votes
1 answer
159 views

How are astronauts aboard the Tiangong space station keeping busy?

Per Wikipedia's Tiangong space station viewed today: Days in orbit: 3 months, 15 days (13 August 2021) Days occupied: 1 month, 27 days (13 August 2021) Currently it is just the single core ...
uhoh's user avatar
  • 149k
4 votes
2 answers
133 views

Has opalescence ever been observed on any solar system body besides Earth? Or at least from a sample from one?

New method for exoplanet detection based on iridescence? in Astronomy SE asks about observations of exoplanets, but here I'm asking about our own solar system bodies. Question: Has opalescence ever ...
uhoh's user avatar
  • 149k
1 vote
1 answer
90 views

Has iridescence ever been observed on any solar system body besides Earth? Or at least from a sample from one?

New method for exoplanet detection based on iridescence? in Astronomy SE asks about observations of exoplanets, but here I'm asking about our own solar system bodies. Question: Has iridescence ever ...
uhoh's user avatar
  • 149k
-1 votes
2 answers
737 views

Why does Unity look transparent?

The BBC's Virgin Galactic: Sir Richard Branson rockets to the edge of space includes the image below. Much of the Unity spacecraft appears (almost) transparent in this image; you can see the blue sky ...
uhoh's user avatar
  • 149k
1 vote
0 answers
48 views

How big of a telescope will Psyche's deep space optical communications demonstrator use out at 5 AU?

NASA JPL News item says: The spacecraft's instrument payload includes three science instruments. The mission's magnetometer is designed to detect and measure the remnant magnetic field of the ...
uhoh's user avatar
  • 149k
3 votes
1 answer
137 views

Does Perseverance's SuperCam include a Martian meteorite? If so, why?

An automotive blog claims that There actually seems to be another Martian meteorite being sent to Mars, as part of the SuperCam calibration target. Shouldn’t we be keeping all the Mars rocks we have ...
Camille Goudeseune's user avatar
1 vote
0 answers
76 views

Has Made in Space any track record growing specialty crystals in microgravity before? ("Industrial Crystal Facility" to fly this year)

Ars Technica's There are an insane amount of cool space things happening in 2021 mentions: This year, Made in Space's "Industrial Crystal Facility" should also fly to space. This will serve ...
uhoh's user avatar
  • 149k
2 votes
1 answer
296 views

Will future deep space optical communications "ground stations" actually be in space, or on the ground?

Deep space communications ground stations are on the ground because their transmit and receive electronics alone is bulky and heavy, not to mention their 34 and 70 meter dish antennas! But those ...
uhoh's user avatar
  • 149k
31 votes
3 answers
7k views

Does it make any scientific sense that a comet coming to crush Earth would appear "sideways" from a telescope and on the sky (from Earth)? [closed]

In multiple different movies and fiction, there's the threat of a burning space comet heading for Earth, threatening to kill everyone and destroy the planet. One example is the animated Comet in ...
Snusmumriken's user avatar
6 votes
4 answers
760 views

First LED left on another planet⁺ by humans?

Light Emitting Diodes or LEDs are ubiquitous now, but I still remember riding my bike to Radio Shack and buying my first LED, checking the diagram on the back of the package, and getting a battery and ...
uhoh's user avatar
  • 149k
3 votes
0 answers
106 views

Are there any possible proxies for dust accumulation on the retroreflectors on the moon?

New York Times' How Do You Solve a Moon Mystery? Fire a Laser at It links to the new open access paper First two-way laser ranging to a lunar orbiter: infrared observations from the Grasse station to ...
uhoh's user avatar
  • 149k
19 votes
3 answers
4k views

Is there any way that real stars would move like they do in the classic Windows 3.x screensaver if traveling through space at extreme speed?

In old versions of Windows, such as 3.1, there was this screensaver called "Starfield". It looked like this: However, in movies and TV series, it usually looks like ...
Zamaree Riales's user avatar
3 votes
1 answer
169 views

Determine envelopes for the payloads?

I am a mechanical engineer who is trying to expand my domain knowledge in aerospace and am currently reading a book to increase my understanding of it. I am mostly interested in studying the design of ...
D R's user avatar
  • 33
2 votes
2 answers
675 views

When will a moon landing site be visible via telescope?

Telescope technology is advancing. Logically there should be a point where clear images of the landing sites are visible. I am guessing a 1km telescope would be plenty. If we currently have 100m ...
user33880's user avatar
10 votes
1 answer
2k views

Why is there no microscope on the Mars 2020 rover?

Good magnification microscopes seem both light and cheap. As far as I could find out, there hasn't ever been one on any Mars rovers. The closest I could find is the Mars Hand Lens Imager (MAHLI) which ...
SCH's user avatar
  • 203
5 votes
1 answer
1k views

What is the "space grease" used to lubricate the ISS robotic arm? What are the material considerations for it?

Space.com's Spacesuit Gloves Contaminated During Friday's Historic Spacewalk quotes NASA astronaut Christina Koch (Wikipedia, NASA): "And so," she continued, "of course, a mechanical ...
uhoh's user avatar
  • 149k
1 vote
1 answer
94 views

Why was the central obstruction in Galileo's Solid State Imager (SSI) so large? Was the secondary mirror flat?

According to Wikipedia's Galileo Solid State Imager (SSI) The SSI was an 800-by-800-pixel solid state camera consisting of an array of silicon sensors called a charge-coupled device (CCD). Galileo ...
uhoh's user avatar
  • 149k
5 votes
1 answer
537 views

What's the largest optical telescope mirror ever put in space?

As a follow-on question to What's the largest optical lens put in space? I'd like to ask about mirrors this time. Question: What's the largest optical telescope mirror ever put in space? Optical ...
uhoh's user avatar
  • 149k
5 votes
1 answer
526 views

What's the largest optical lens put in space?

While star cameras and wide angle cameras in space are built from glass lenses, large aperture optical systems generally use reflective optics. For some large ones see answers to What's the largest ...
uhoh's user avatar
  • 149k
14 votes
2 answers
642 views

How fast do optical surfaces get dirty or damaged in space?

These answers: (1, 2) to Do things get dirty in space? mention the Hubble Space Telescope but if I understand correctly refer to the outside of the telescope rather than its optical surfaces. Answers ...
uhoh's user avatar
  • 149k
9 votes
1 answer
465 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
  • 149k
1 vote
1 answer
178 views

How would 2 JWSTs make stereo pictures?

Could 2 JWST be launched in opposite directions to provide stereo vision? Would a stereo picture provide any benefit? https://space.stackexchange.com/a/35402/18879 Related: How will JWST manage ...
Muze's user avatar
  • 1
1 vote
2 answers
282 views

Have optical zoom systems been used in space exploration?

Here, 'optical zoom' means an optical system that changes magnification (angle subtended per pixel). It would not mean for example switching from one camera to another on Hubble, or changing to ...
uhoh's user avatar
  • 149k
5 votes
0 answers
105 views

What are the space-based optical satellite sensors?

I was looking at a products page for Numerica Corp, and under their product MFAST it said (emphasis mine): Tracks objects in all regimes of space (e.g., LEO, MEO, HEO, GEO) using radar, ground-...
NeutronStar's user avatar
  • 1,049
0 votes
2 answers
335 views

How does the camera make the exhaust of the Electron's RP-1/LOX exhaust transparent?

In this 20-Nov-2018 Tweet from Rocket Labs XXX Peter Beck there is an image of the nine Rutherford engines of an Electron rocket burning. What is unusual is that the exhaust is luminescent but at the ...
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
7 votes
2 answers
1k views

How does the thin gold film in the glass of spacesuit helmets block thermal IR but transmit visible? What's the property?

Comments below this answer suggest that there is a thin gold coating on the glass of spacesuit helmets that blocks thermal IR (say roughly about 10 to 30 microns) but is mostly transparent to visible ...
uhoh's user avatar
  • 149k
3 votes
0 answers
53 views

What would be the equivalent camera performance specification of Earth-imaging satellites, compared to consumer DLSRs?

In order to better understand what Earth imaging cameras are like (as seen in Google Earth) from the point of view of a photographer, I've asked the following. Consumer-grade cameras like DSLRs, ...
Basher's user avatar
  • 131
40 votes
3 answers
13k views

Is pinging the Moon with a laser as shown on "The Big Bang Theory" possible?

In an episode of season 3 of The Big Bang Theory, the cast sends a laser pulse to the Moon. This seems to be a real thing: What Neil & Buzz left on the Moon (2004). My questions are: Could ...
Dmytro Khmara's user avatar
4 votes
1 answer
262 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
7 votes
1 answer
229 views

How could the laser from Earth to a spacecraft be used other than to propel its light sail?

The Starshot Breakthrough Initiative, sponsored by Yuri Milner, now finances the attempt to use a huge laser on Earth to propell a tiny spacecraft to huge velocity. Not having to carry the energy for ...
LocalFluff's user avatar