Tiny satellites ushering in a new space revolution(bloomberg.com) |
Tiny satellites ushering in a new space revolution(bloomberg.com) |
They have sent about 200 satellites, cost "six figures" each, so an estimate of 200,000 a piece, they have spent about 40 million dollars, excluding the price of launches.
The data collected is definitely worth the price IMO. Imagine the ability to monitor storms and hurricanes, analyze their data and update our climate models.
They have about 80 million in funding alone, which is incredible.
I wonder what else is possible with so many eyes in the sky.
Skylabs had seven high-res SkySat satellites that Planet got via acquiring Skylabs/TerraBella complementing its existing fleet of medium res satellites.
Planet’s existing network could only get three to five meter resolution, while Skybox’s satellites could manage “sub-meter" accuracy.
80 million in funding seems low. The price of the Skybox/TerraBella acquisition from Google alone had to be in the hundreds of millions.
As of April 2015, Planet had raised $183M according to https://techcrunch.com/2015/04/13/planet-labs-rockets-to-118...
I was one of the first people to consume their v0 and v1 APIs to get their analytic imagery dataset. It was more challenging than it should have been to transfer ~100TB into our compute cluster. I haven't touched their API in about 7 or 8 months, but from my last meeting with them they said they have eliminated my top pain point. Looking forward to seeing more great things from them.
1. Price was to high for the value we could offer
2. 40% chance we wouldn't get a usable image of the field due to cloud cover
3. Its one data point, you can see a problem but can't always figure out what's wrong.
I'm really hopeful for drones that can operate below the cloud cover and AI that can take bare soil images, tile maps, soil tests and provide a more intelligent answer for fixing the problems.
What the farmer wants is a prescription with a shot at a decent ROI.
Any of the above to name a few
There is some amount of atmospheric drag in low earth orbit which will eventually cause satellites at that altitude to lose speed and fall back to earth, but that drag is small enough that the satellites should be able to remain in orbit for years without needing any additional thrust.
This means the intention is indeed for re-entry into the atmosphere after the operational lifespan of the dove has lapsed. (They physically stay in space only a few years depending on altitude, orbit, exposed atmospheric drag and a couple of other things)
The last two flocks alone have put close to 130 sats in space so the debris issue is something that is taken quite seriously at the company.
Source: I work at planet. I generally lurk on HN but I created an account just now to reply to this :)
EDIT: Relevant blog post from a couple years ago - https://www.planet.com/pulse/keeping-space-clean-responsible...
Are there any steps taken to ensure the satellites de-orbit in a timely manner? Are there any estimates on how many of the satellites will de-orbit and when, absent such an intervention?
How? By a burn? That's a lot of fuel reserve to use up.
[1]. http://www.esa.int/spaceinvideos/content/view/embedjw/484820
Turning them to look outwards might just capture something if it happened to be inside the size of patch and whatever the telescope/camera combo can focus on (which would be the LEO distance plus or minute a bit). But space is big, even at 500km above the earth, so the likelihood of finding something in your field of view such as another satellite is probably quite low. Stars and other astronomical objects might be too dim/out of focus.
[Disclaimer: not a rocket scientist]
How much fuel do you imagine it takes a satellite to re-enter if it will happen automatically in a matter of a few years?
The answer to both is, of course, not much, not much at all.
It's possible that the problem will take care of itself, but the information provided is not adequate to model the problem and prove that the problem will take care of itself.
Post collision, all debris orbits will still be passing through the point of collision. Any deflection with a vertical component (up or down towards the earth) will have a part of their orbit go through thicker atmosphere, which will make them deorbit faster. That leaves deflections which are in the plane spanned by the two orbits ("sideways" and "forwards/backwards"). If those deflections in any way slow down the piece of debris, that will also go through lower atmosphere and deorbit.
Disregarding debris under those effects, the remaining debris will have two more things going for it: They'll be out of the LEO orbit for a large part of their (now elliptic) orbits, and they'll be smaller so they'll slow down more from friction (due to the square-cube law).
Of course, cascading effects could still affect all satellites in LEO (and humanity's access to orbit for years), but it doesn't seem to me like it'd be a "permanent" issue in LEO? What am I not seeing?
This is not too dissimilar to the process of evaporative cooling in a liquid, or gas escape from an atmosphere.
My gut feeling says that statistically, even just going from one impact to two impacts being likely would require an immense density of satellites, let alone having more collisions than that.
Then there's also the fact that every impact would have a loss of kinetic energy (because it gets converted to heat as the objects deform), which would also make a reduction in orbit likely.
If the debris keeps fragmenting, which maybe could increase odds of impact, the remaining kinetic energy would be divided over each object. The smaller the debris gets, the more drag it should feel too, because of the square-cube law[0]. So that too would only make it more likely to deorbit.