The radiative flux on an object such as a bird, airplane, or spacecraft moving through the beam would be about the same as the output energy flux at the beamer, or 100 kw/m2 – about two orders of magnitude above sunlight on Earth. This is hazardous to birds with respect to both temperature and eye damage. For aircraft and satellites, this is also hazardous with respect to heating as well as sensor blinding.
There are two approaches to mitigating this risk: administrative (warnings) and an ‘active failsafe interlock perimeter detection system’. This system consists of visible light-, radar-, and laser-based air-scanning modes. These systems are so arranged as to have buffer zones (no fly zones) of several minutes of flight time for the average object in each flight regime (birds, airplanes, spacecraft). It could be ensured that we several minutes’ clearance was given prior to any beaming. Before commencement of launch operations, all incoming objects would be tracked. The main emitter could be turned off extremely rapidly (sub-microsecond response); so that once a prediction were made of a violation of the no fly zone, the mission could be aborted.
Apr 13, 2016 08:49
Rj Hillan
Posted on: Breakthrough Initiatives
It could just be the two cups of coffee and sleep deprivation thinking here, but I would suggest looking into the use of drones. You could use multiple drones placed at multiple altitudes, circling the airspace and armed with sensors to detect and track any object flying near the beam(s).
So simply put, if a bird was to fly towards the beam(s), the drone or drones would detect the object and remotely shut down the laser systems, or inform personnel of a detected object or debris. The drone would relay the approx. location and heading of the object (bird, civilian drone, etc.).
I believe this would be a cost effective method, since drones will be able to stay in the air for the required amount of time. plus the drones would not need to be very expensive, the sensors would be the most expensive components.
Apr 13, 2016 15:24
Christoph Borst
Posted on: Breakthrough Initiatives
How about using micro satellites both as platform for the laser (one satellite) and as launch platform (second satellite)?
This would mitigate object in beam path issues, and potential atmospheric interference (power loss by atmospheric particle reflection?). Additional questions around how big and heavy the laser platform could be, and how to store energy / re-fill the laser satellite would need to be answered.
I can imagine that micro satellites (if technically feasible) will definitely be cheaper to realise in the short run compared to land-bound platforms. Only a detailed business case could determine if this is also a worthwhile longer-term.
This is just blue sky thinking now, but how about a laser on the ISS?
Apr 13, 2016 15:42
John McLean
Posted on: Breakthrough Initiatives
Putting the laser array in orbit is a total non-starter given the power and cooling requirements. The power requirement is 100 GW (admittedly only for a few minutes, but nevertheless). To put this in context, the largest power plant in the world (the Three Gorges Dam in China) has a capacity of 22.5 GW. The largest nuclear plant outputs just 8 GW.
Jun 13, 2016 14:41
michael.million@sky.com
Posted on: Centauri Dreams
If the laser position is high up on a mountain the chances of a bird fry or plane hit is much smaller as birds and planes tend to avoid these regions due to cold and strong winds.
Aug 01, 2016 14:40
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
Jun 13, 2016 14:41 michael.million@sky.com Posted on: Centauri Dreams
"If the laser position is high up on a mountain the chances of a bird fry or plane hit is much smaller as birds and planes tend to avoid these regions due to cold and strong winds."
Standard rocket launch range safety with avoidance of migratory seasons for the birds should suffice for the atmosphere. For space, we will use data from the tracking of space debris and human objects.
http://www.nasa.gov/mission_pages/station/news/orbital_debris.html
Note that this tracking is improving and that the beamer could be also used to destroy space debris.
Beamer location requirements are similar to ground telescopes, plus southern hemisphere location and minus the light pollution requirement. The Atacama site is promising.
– Prof. Sasha Buchman, Breakthrough Initiatives
Apr 20, 2017 03:30
Peter Jaquiery
Posted on: Breakthrough Initiatives
Placing the launching array on the moon provides a number of advantages (and obvious disadvantages):
1/ No atmosphere to mess with beam pointing and object tracking
2/ on the far side of the moon there is likely less concern over high power collimated energy sources
3/ there's lots of free sunlight
4/ sidereal rate is much low so launch windows can be longer (although less often)
5/ Radiative cooling is king (but convection really sucks)
6/ (almost) no space debris
7/ no birds or high flying aircraft
Jul 15, 2017 03:28
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
RE:
Apr 20, 2017 03:30Peter Jaquiery Posted on: Breakthrough Initiatives
Answer:
You’re completely right that there would be many advantages to building the laser system on the moon. Unfortunately, we don’t think it be economically feasible in the next few decades.
- Zac Manchester, Breakthrough Starshot
Nov 15, 2020 00:46
John Weiss
Posted on: Breakthrough Initiatives
What about crafts getting in the way of each other's beams?
Jan 26, 2022 18:12
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
Dear John,
The launch cadence of the sailcraft is unlikely to exceed a maximum of 1per day by which time, the sailcraft would be out of reach of the focused beam.
James Schalkwyk
Breakthrough Starshot
