Questions tagged [laser]

Questions regarding devices which emit focused beams of electromagnetic energy.

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8
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1answer
2k views

What are these structures on the Lunar Ranging Retro Reflector (LRRR) arrays for?

In Local expansion measured, near zero via Lunar Ranging - what about deep space probes? I used images of the retro-reflector arrays that were left on the moon by Apollo 11, 14, and 15. The Lunar ...
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2answers
422 views

Is it possible to extend high speed data transmission with lasers to the distance Earth to Mars?

Data transmission using an optical laser between ground station and a GEO satellite may offer very high data rates, up to 1.8 GBit/s for instance. But what about a transmission from Earth to Mars ...
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286 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 ...
7
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1answer
469 views

How much power loss does the LLCD suffer in transit?

Space.com writes to say (freeform improved quote): The LLCD (Lunar Laser Communication Demonstration) space terminal is designed to beam data from the moon at a rate six times faster than the best ...
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1answer
1k views

How does QUESS, China's quantum communications satellite experiment, relay entangled signals?

China launched the Quantum Experiments at Space Scale (QUESS) on the satellite called MOZI or Micius today, which will be used for quantum communications between China and Europe. Popular Science ...
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645 views

Breakthrough Starshot's 100 Gigawatt laser array - what's the current thinking how this might work?

In the article Breakthrough Starshot tricks out massive telescope for planet hunting there is casual mention of a "phased array of lasers in the 100GW range" that will propel a gram scale spacecraft ...
4
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1answer
280 views

How accurate can near earth asteroids be tracked?

To get more statistical significance for the suspected flyby-anomaly (or to refute it), it would be desirable to track as many hyperbolic earth flybys to within 1mm/s as we can get. Can we track ...
2
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1answer
54 views

How did LADEE and LDRC measure it's distance from Lunar orbit to Earth to 1 centimeter accuracy using optical communications?

The video Donald Cornwell plenary talk: NASA's Optical Communications Program: 2015 and Beyond was presented at SPIE Photonics West 2015. It's a great talk and worth the time. LADEE had [the Laser ...
43
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3answers
12k 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 ...
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4answers
4k views

Laser propulsion possible?

Is it possible to get an impulse, if you shoot at a solar sails with lasers mounted on the spaceship? If so, why doesn't a laser create a force, if it fires/releases a photon? Is the impulse ...
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1answer
2k views

Do the latest Starlink satellites use inter-satellite laser communications?

Do the latest (as of Jan 30, 2020) Starlink satellites use inter-satellite laser communications? I can't find any info about that!
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618 views

Are we actually that close to techniques of accelerating probes to speeds like a quarter $c$?

As recent research has been started by a team around Stephen Hawking under the name Breakthrough Starshot they are going for accelerating little probes up to 0.2~0.25$c$. There isn't that much ...
9
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1answer
458 views

What's the current timeline for NASA's Mars orbiter laser communications?

Dr. Jim Green, Director, NASA Planetary Science Division, mentioned during his "The Martian": Science Fiction & Science Fact talk for the 18th Annual International Mars Society Convention (you can ...
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122 views

How to get an initial setting of the range gate for a Lunar Laser Ranging using a new Retro Reflector for the first time?

From an answer to this question They were searching by aiming their laser at the moon and looking for reflections. But the system is set to only detect photons in a very narrow range of ...
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1answer
130 views

Would an incandescent light bulb be more efficient than a laser for photon propulsion?

In an incandescent light bulb pretty much almost all of the input power is radiated as photons. While perhaps 10% of the power is useful for human vision and the rest are longer wavelengths, it's all ...
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2answers
336 views

Can you launch a probe to the Moon using a laser propelled craft?

Take a very light object, propel it with a laser source on Earth at a constant acceleration. Can this object reach the Moon? Could this be more reliable than a rocket? (supposing solar panel energy ...
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1answer
150 views

Why does LRO's laser altimeter telescopes use lenses instead of mirrors?

From Space.com's NASA's Piggyback Experiment on Israeli Moon Lander Could Aid Future Lunar Touchdowns shows an image of the laser altimeter on the LRO. It looks like the "transmit" and "...
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1answer
141 views

When they shoot lasers at the Moon for ranging, what is the shape of the beam?

Laser ranging of the Moon is usually done with a Q-switched pulsed laser fed into a big (1 or 2 meter diameter) telescope as a collimator in order to get a tight beam all the way to the Moon in hopes ...
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254 views

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

A comment below @A.Rumlin's answer to Is there any spacecraft that is ping-able? links to a Facebook page (in Russian) which shows an astrophotographer's photograph of stars plus a big green flare ...
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121 views

Could a laser ablation-based propulsion system really accelerate an object to 0.001 c?

Comments below this answer suggests that a laser ablation-based propulsion system, where the laser is separate from the object to be accelerated, could accelerate an object to about 1/1000 of the ...
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3answers
445 views

How would a laser "shoot down" space junk?

This question links to an article describing a ground-based laser designed for shooting down orbiting space debris: "The scientists intend to use the massive soon-to-be-built telescope at the Altay ...
5
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1answer
327 views

Attitude requirements for inter-satellite laser communication

Previous questions have address the beam divergence angles and the expected signal attenuation for laser communication between spacecraft. However, I was wondering what is a typical receiver aperture ...
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2answers
680 views

Characteristics of the inter-satellite optical link

I'm currently diving into this topic and as I understand from the brief search there are two main types of inter-satellite link: radio and optical. As I can see, one of the main distinction of optical ...
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1answer
72 views

Did Perseverance get an experimental optical communications terminal?

The video Donald Cornwell plenary talk: NASA's Optical Communications Program: 2015 and Beyond was presented at SPIE Photonics West 2015. It's a great talk and worth the time. Near the end at about <...
2
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1answer
172 views

Small probes to Alpha Centauri powered by light sails with a journey time of 20 years

This news item states that scientists have potentially devised a way to send a number of small probes to Alpha Centauri at quarter the speed of light. The journey would take 20 years and each small ...
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1answer
68 views

operating wavelength of lasercom

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 ...
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1answer
256 views

Can a laser be used to clear the launch path of a rocket?

Military grade lasers shooting down incoming missiles have been in the news since Ronald Reagan was the US president. The problems, as I recall are mostly about diffusion in atmosphere. The Kessler ...
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67 views

Could outer system probes detect lasers shone at them from earth (orbit)?

Does the Voyager spacecraft have instruments capable of detecting laser light if shone at them? New Horizons certainly does. Any other probes? Is there any laser capable of accuracy and power enough ...
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1answer
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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 ...