Author Topic: ISRO developing LASER propulsion (Read 14307 times)

GareebScientist · « **on:** 05/25/2018 05:47 pm »

ISRO Chief K Sivan recently admitted to the fact that LPSC or Liquid Propulsion Systems Center is developing LASER propulsion .
Article - http://gareebscientist.com/isro-developing-laser-propulsion/

What do you think of this development ? very few details . Anyone working from ISRO LPSC could clear out the details .
Its definitely exciting tho.

i wonder if their concept is similar to Breakthrough Starshot.

johnfwhitesell · « **Reply #1 on:** 05/25/2018 09:27 pm »

Cool but I'm scratching my head at the four minutes to mars thing.

speedevil · « **Reply #2 on:** 05/25/2018 09:37 pm »

I wonder if someone has gotten the wrong end of the stick.

Quote

“It is not just the aircraft, the target is to develop light craft using laser propulsion for interplanetary mission. With such light craft, powered by high speed laser propulsion, it will be possible to go to Mars in four to eight minutes and the challenge is for LPSC to play a lead role in developing that,”

You can almost read that as microsatellite small launchers, which launch to Mars and finish burns at 4-8 minutes.
Add in a mishearing/quote/translation of 'high speed laser communication' and you're about there with reasonable things for them to be considering.

GareebScientist · « **Reply #3 on:** 05/26/2018 03:38 pm »

I think they are developing a technology demonstrator. Wonder if they are serious about this.
We can have a relatively small laser at. L1 orbit.
Although it will require huge solar panels to generate let's of energy

speedevil · « **Reply #4 on:** 05/26/2018 04:19 pm »

Quote from: GareebScientist on 05/26/2018 03:38 pm

I think they are developing a technology demonstrator. Wonder if they are serious about this.
We can have a relatively small laser at. L1 orbit.
Although it will require huge solar panels to generate let's of energy

You almost can't.

A 1m mirror, for example shining LASER light has to output >>1kW, or there is no point at all. (*)

At say 100kW, the photon pressure is 1/3000N or so, reflected off a mirror.
The thrust halves after the beam expands to 1.4m, assuming ideal targetting of a small sail, which happens after around 1500km.

That is a gain in kinetic energy of 1500km*1/3000N = 500J.
If the object weighs 10g, that is 200m/s over about a couple of hours.

Smaller makes this much, much worse.

100kW and a 1m aperture dish is 'ridiculously large' by the state of todays technology.

*) In principle a small amount of use could be had as you can now tack between the two sources of light.

GareebScientist · « **Reply #5 on:** 05/27/2018 08:55 am »

Or what they can do is have a gas inside a chamber 2hich the laser could heat leading to rapid expansion.
A compressed ablative material could also do I guess?
But we may not reach the speeds he is talking about