NASA Survey of Astronomers

[Terry B]

An email I received

Dear Fellow,

We’ve been contacted by Dr. Jennifer Inman, a physicist for NASA Langley Research Centre. She has asked if you would be interested in helping to enlighten NASA researchers about your telescope usage and astronomical viewing habits by taking a short survey.

Dr Inman is conducting a probabilistic risk assessment of the hazard potentially presented to the general public as a result of NASA’s satellite-based climate science lidar measurements.

They’ve been working with the Astronomical Society of the Pacific and the NASA Night Sky Network to formulate initial estimates of many of the input parameters used in their calculations (e.g. number of amateur astronomers, distribution of telescopes by entrance aperture, frequency of telescopic observations, etc.). They’ve begun a higher-fidelity Monte Carlo analysis and want to try to refine some of their estimates.

To that end, they’ve put together a survey targeted at astronomers. You can complete the survey here: https://goo.gl/forms/E7n4Xrvp3oQqmCYn1.


***Please note that this is a request from NASA. I will not be able to answer any questions about the project or the survey.***


Best wishes,

Annie Hogan
Memberships Officer
Royal Astronomical Society, Burlington House, Piccadilly W1J 0BQ, UK

[gary]

Thanks for forwarding Terry.

This is certainly a very important notice.

As the additional information section of the survey states :-

Originally Posted by NASA

We're conducting this survey as part of a probabilistic risk assessment of the potential hazards presented to the general public by spaceborne lidar systems. NASA and its partners (including CNES and ESA) use lidar on satellites to make measurements of Earth's surface and atmosphere. Examples include CALIPSO, CATS, ALADIN, and GLAS. Lidar works on the same time-of-flight principle as radar, but using a laser instead of a beam of radio radiation.

The lidar lasers on satellites greatly exceed eye safety standards for observers on the ground for direct, unaided viewing of the laser beam. But, with sufficiently powerful light-collecting optics, it would, in theory, be possible to exceed the retinal damage threshold. So please, NEVER LOOK DIRECTLY INTO A LASER WITH YOUR EYE. We really don’t want to injure anyone! To that end, we're attempting to calculate the odds of one of these lasers causing injury to make sure the risk has been mitigated to an acceptably low level (e.g. lower than the odds of being injured by a piece of orbital debris from the satellite itself when it reenters Earth’s atmosphere someday, which is another risk we must calculate and mitigate to internationally-agreed-upon acceptably low levels).

We’ve so far done our best to model the problem, but many of our input parameters are only educated guesses. For instance, while we can calculate the energy per area that would result from standing in the laser footprint and viewing the beam through a given size and type of telescope, we don’t know how many such telescopes are in use at any given time. Larger telescopes carry a higher risk of injury, but we suspect larger telescopes are less common since they cost more. And if someone is doing all-night observations, we suspect it’s more likely that they’re using a sensor/camera rather than their eye, e.g. for recording star trails or doing long exposures of faint objects.

The particular orbital parameters of our various satellites also affect our modeling. A laser on the ISS has a non-repeating ground track that paints the mid-latitudes but never the polar latitudes and can pass overhead at different times of night. The A-Train constellation of satellites, on the other hand, has a repeating ground track, flies in a solar-synchronous orbit, so it paints all latitudes and always passes overhead at approximately the same time of night. So, the odds of injuring someone depend on things like the percentage of people still out observing at 2 am and whether active astronomers are distributed by latitude in proportion to the overall population.

If you decide this is a phenomenon you want to see for yourself, be sure to make your attempt using a camera rather than your eye; if you are successful, not only will you avoid the risk of retinal damage by using a camera, you'll also have an image to prove you saw the laser flash. A picture is much more convincing than, "Hey guys! I saw a flash of light from space!" And if you're feeling generous, we'd love it if you'd share your images with us. See contact information below.

Definition of Acronyms and Links to More Information:

Image of lidar pulse captured by Gregg Hendry of Ball Aerospace
https://www.nasa.gov/larc/calipso-laser-flash
https://www.facebook.com/nasalarc/ph...3964850983168/

CNES: Centre National d'Études Spatiales (the French government space agency)

ESA: European Space Agency

CALIPSO: Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation.
CALIPSO website: https://www-calipso.larc.nasa.gov/

CATS: Cloud-Aerosol Transport System
CATS website: https://cats.gsfc.nasa.gov/

ALADIN: Atmospheric LAser Doppler INstrument
ALADIN website: http://www.esa.int/Our_Activities/Ob...Aeolus/Payload

GLAS: Geoscience Laser Altimeter System
GLAS website: https://attic.gsfc.nasa.gov/glas/

[deanm (Dean)]

Bloody hell!
They are seriously concerned about blinding folk like us.
There must be some lawyers haunting these IIS pages: what liability might be involved? Who would pay compensation/damages?
How would fault be established ("I was looking through may 'scope last night & suddenly, my eyeball exploded.."!)
Dean

[sil (Steve)]

Thanks Terry!

Hope the amateur input is taken seriously and not just a pr stunt to make it look like due diligence. I choose to believe the former.

[Wavytone]

I'm waiting for the headline on the Daily Telegraph "NASA's orbiting lasers blinding pilots at night..." I wonder how the legal laser nazis will react.

More to the point an orbiting LIDAR might be the cause of occasional flashes reported that don't correlate to an iridium satellite or similar.

[Suzy]

Oh charming... It's getting harder to look through a telescope , not only do we have to contend with light pollution on the ground but now dodge being blinded from space. Scary.
And it really worries me that we're only finding out about this now .

Thank you Terry and to Garry for all the info. I'm with Dean, my head spins at the legalities regarding injury .

And if someone is doing all-night observations, we suspect it’s more likely that they’re using a sensor/camera rather than their eye, e.g. for recording star trails or doing long exposures of faint objects.

Fiddlesticks.

[blindman]

Larger telescopes carry a higher risk of injury, but we suspect larger telescopes are less common since they cost more.

What a crap!

If it is true, NASA should be banned from such a stupid attempts!

Maybe global petition would help?

[Wavytone]

Originally Posted by blindman

Maybe global petition would help?

What would more likely nail it is to let pilots know they stand a risk of being blinded - even temporarily - by laser flashes while flying at night. The aviation authorities have zero tolerance to this sort of thing and may have the authority to stop it and tell NASA a looud no, find another solution.

[billdan (Bill)]

I hope our nanny govt' doesn't read this.

"Due to the risk of eye injuries caused by looking through a telescope, all personal telescopes must be handed in to be crushed and only authorised govt' agencies can use telescopes. A $1000 fine will be issued for non-compliance"