
NASA has three smartphones orbiting the earth as mini-satellites - ck2
http://www.npr.org/2013/04/26/178846158/can-you-hear-me-now-cellphone-satellites-phone-home
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spiritplumber
I helped design these (and I think I handbuilt a couple of parts on one of
them). If you have questions ask away!

These were supposed to launch about a year ago, but the rocket kept being
delayed.

The phones are Nexus Ones (and a Nexus S, which I didn't work on so I cannot
comment) with a custom kernel to enable their serial port.

~~~
haliax
What sort of analysis was used to figure out the power and protection
requirements you needed to make these viable?

Are these within reach of an individual to build, if not to launch?

If I build one, how do I launch it?

Why do the signals need to be crowdsourced over Ham?

What are your personal favorite/most cool applications for lots of cheap
satellites?

~~~
spiritplumber
* Mostly trial and error, surprisingly -- the idea was to keep everything in low power mode as much as possible, and see if solar panels would let us keep charge. Turns out that they can; one of the sats has panels. Another just has batteries and will die down.

* Yes, definitely. One of the sats was even hand soldered.

* You talk to NASA, the cost to launch one commercially would be around $20K. We mostly piggybacked on a rocket that was being tested.

* Because there was no budget for following these things on the ground, honestly :) Plus it gets people involved.

* We were talking about having these things detect circular cloud formations to indicate a possibly forming hurricane, and having a "real" weather sat take a better look on its next pass.

~~~
syedkarim
If I paid the $20k commercial price, would I be guaranteed a slot on a rocket?
And do paying CubeSat customers bump off those that were given free tickets?
Is anyone else offering reliable, commercial CubeSat launches for that price
(or less)?

~~~
spiritplumber
Sadly no.

The phonesats waited in a box for more than a year in order to find room.

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drzaiusapelord
Interesting how the press just calls these things "smartphones" but if they
were iPhones, we'd see endless articles about Steve Jobs' vision, iPhone in
the headline, etc.

There's something shameful about how little attention the excellent Android
project gets. Those are Nexus One phones, a phone from Jan 2010. I feel
Android being open and mallable for NASA is pretty noteworthy, but the press
just sells this as a "smartphone" instead of really discussing the technical
platform that makes stuff like this possible so quickly and so cheaply.

~~~
Retric
The problem is unlike iPhone using Android by it's self in a headline is often
ambiguous. Saying Android Smartphone is accurate but while iPhone is shorter
than Smartphone it takes far more space to say Android Smartphone thus the
useage discrepancy. Which is one of the main issues with choosing that
trademark.

~~~
hammock
Reminds me of the old "IBM/Compatible" vs "PC."

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ck2
The launch was kinda neat too:

<http://www.youtube.com/watch?v=V3L7crGudVU>

Finless rocket? How does it steer/stabilize? Do the engines have fine control
over which side their fire perhaps?

I guess fins are useless outside of atmosphere anyway.

~~~
dexen
Probably steered through thrust vectoring. Liquid fuel rocket engines are
often built to gimbal, typically 1...2 degrees to each side.
<http://en.wikipedia.org/wiki/Rocket_engine#Thrust_vectoring>

Another possible method of steering is to build four or more reaction jets
around the rocket; could be fed with a monopropellant or exhaust from the main
engine or its turbopump.

~~~
gngeal
If you can deal with slight decreases in thrust, you can also do thrust
vectoring with injecting water or other suitable liquid into the nozzle in
proper places. Could be mechanically simpler than gimbals in some cases.

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euroclydon
What a lame twist of ageism NPR added to that story. Stay tuned for part two,
where the kids teach Crockrell how to tweet and check his email.

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johnabowen
One of the largest CubeSat (the form factor of these satellites) conferences
is actually happening right now. It can be live streamed or replayed here:
[http://mediasite01.ceng.calpoly.edu/Mediasite/Catalog/pages/...](http://mediasite01.ceng.calpoly.edu/Mediasite/Catalog/pages/catalog.aspx?catalogId=36b100d1-069a-4bac-b7e3-8a9512655e78)

You can find out more about who else is building this type of hardware here:
<http://cubesat.org/index.php/collaborate/suppliers>

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ck2
Imagine someday where many people own their own personal satellite.

Not sure what it would be useful for on a personal level, but I bet they will
come up with something.

I also wonder if they could send 1000 to orbit the moon or another planet in a
network to do surveys.

~~~
lutusp
> Imagine someday where many people own their own personal satellite.

Nice thought, but (unless the satellite is in geostationary orbit, very
expensive) it won't work. Imagine having your own personal satellite that is
only accessible for perhaps two short periods in 24 hours (for a mid-northern
latitude location).

Better to have a subscription to a system with dozens of shared satellites in
random orbits, available 24-7.

~~~
Isamu
Having your own mapping/sensor satellite would be interesting. You'd need a
polar orbit to get really complete coverage, but more likely most of what
you'd be interested in is in the lower latitudes and some orbit that is
inclined from the equator some amount is all you'd need.

[edit] Here's a catalog of satellite orbits courtesy of NASA:
<http://earthobservatory.nasa.gov/Features/OrbitsCatalog/>

~~~
lutusp
Thanks! I was actually (and perhaps naively) thinking only of a radio relay
satellite, not one with optical sensors. Your description is much more
interesting.

Once this happens -- once cheap optical survey satellites come into existence
(and they will) -- governments are going to go completely nuts. Right now,
governments can put pressure on the few survey satellite operators to blur out
certain sensitive locations (as in a recent story posted here). But once cheap
satellites come into existence, that option will evaporate.

~~~
jodrellblank
Probably before that happens with satellites, it will happen with solar
powered high altitude remote control planes, and mounted cameras. Consumer
level not military spy drone level.

There's already a driver for this technology - flying the plane while wearing
a head mounted display - a currently expensive niche hobby.

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naftaliharris
The picture on that article is really misleading--it looks like you're seeing
the curvature of the earth, and are therefore high up in space, but it's
probably just the effect of a fish-eye lens, as evidenced by the curved upper
surface and the distorted box.

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leeoniya
couple thoughts.

1\. isnt this small enough to look like space debris, and maybe dangerous?

2\. "The mobile phones are designed to be thrown around the room and for
people to drop them in water. They're really robust bits of technology," --
i'm not sure how this physical durability has any bearing on its performance
in near absolute-zero temps and in the radiation of space without being using
radiation hardened silicon...not to mention that it would never be subjected
to any of the things described.

~~~
jerf
"isnt this small enough to look like space debris, and maybe dangerous?"

The fact that they said this burns up when it runs out of "juice" implies that
it is in very low Earth orbit, where the atmosphere still exists and imparts
drag. These will reenter the atmosphere on a moderately predictable time scale
and burn up. Space junk is only a problem at higher orbits which can be stable
for very long periods of time without propellant.

As for 2... they put on up and it worked. What's the point of theorizing about
how it might not work, when they've already done it? It might stand up to a
good solar blast, but that's hardly a surprise, and if it's disposably cheap,
who cares?

~~~
leeoniya
"It might stand up to a good solar blast, but that's hardly a surprise, and if
it's disposably cheap, who cares?"

the phone itself might be cheap, but putting it up there is most certainly not
(yet)...which is why most things that are designed to go into orbit are
expensive :(

would you care to spend 150k+ to put a $300 cell phone into space for 2 weeks?

~~~
grinich
Cubesats are always secondary payloads, usually jettisoned after the first
main stage burn. Their mass is insignificant compared to the main payload, so
they usually ride for free.

<http://en.wikipedia.org/wiki/CubeSat>

~~~
natosaichek
So I can't speak for all conditions, but cubesats do not usually ride for
free. The prices I've seen are usually in the 50k / unit range. So if you've
got a 1U cubesat, expect to spend at least 50k on launch. Part of the reason
for this is that there are integration costs for attaching a cubesat deployer
to an existing launch vehicle, as well as liability risks, control and thrust
timing modifications etc.

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n3rdy
Not sure if this is off topic, but shouldn't it be simple to make a high
altitude balloon out of a material that doesn't explode so easily when it gets
to the lower pressures in low earth orbit?

Or even some kind of contraption that slowly releases gas from the balloon as
it detects lower pressure in the atmosphere to help it maintain altitude and
prevent the balloon from rupturing?

~~~
ck2
Can you actually get something into ORBIT via balloon?

That doesn't sound plausible but I could be wrong.

~~~
andyjohnson0
With just a balloon, no.

To get something into a stable orbit you have to get it high enough to avoid
significant atmospheric drag. In practice this requires an altitude of at
least 200km [1] - although even at this altitude an orbit will decay fairly
rapidly. The IIS orbits at 400km and most remote-sensing satellites are at
500km+.

Contrast this with Helium balloons, which usually top-out at an altitude of
35-50km with the record being 53km [2].

To stay in low-earth orbit you also need an orbital velocity of 7.8km/s. A
balloon launched at the equator has about 0.5km/s horizontal component of
velocity due to the earth's rotation and will not gain any as it lifts.

What you could do is use a balloon to carry a rocket up to its height ceiling
before igniting [3]. This saves on fuel, but there are safety issues caused by
the non-steerability of the balloon.

[1] <http://en.wikipedia.org/wiki/Low_Earth_orbit>

[2]
[http://en.wikipedia.org/wiki/Flight_altitude_record#Unmanned...](http://en.wikipedia.org/wiki/Flight_altitude_record#Unmanned_gas_balloon)

[3] <http://en.wikipedia.org/wiki/Non-rocket_spacelaunch#Balloon>

~~~
curtis
One advantage of launching a rocket from high altitude is that the optimal
rocket nozzle shape and size changes substantially depending on the ambient
air pressure. For example, the Space Shuttle Main Engine is about 25% more
efficient in vacuum than at sea level.

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th0ma5
Just a note for Amateur Radio operators, they are seeking help in hearing the
packets!

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taylorbuley
The U.S. government apparently places commercial restrictions on the kind
technology that makes this kind of wonderful technology (and possibly
scientific) innovation possible for the everyman. For example, a rocket
enthusiast once told me that any GPS chip sold on the commercial market can't
function past Mach 1. Sad to think that even with basically quotidian
materials now putting space in reach of the common man, during my lifetime it
will still be an alien thing and the business of billionaires.

~~~
ohazi
It's 1000 knots and 60,000 ft, and this is only to meet U.S. ITAR export
requirements. There's nothing inherent about the civilian GPS signal itself
that prevents you from computing a fix beyond those limits.

For example, you could buy one of these:
<https://www.sparkfun.com/products/10981>

and then design a baseband yourself. I'm currently aware of at least three
people that are working on this or have already done it. You'll need to
actually take the time to learn how GPS works, and it'll probably take you
about a year, but it's definitely possible.

~~~
spiritplumber
It's called COCOM limit (historical reasons), and you can have it turned off
at the factory if you can talk them into it / have a valid reason to. Oddly
enough "we want to send up a small satellite, and we are calling from a NASA
facility" was not a good enough reason. Surprisingly GPS will work decentish
in LEO, if you can get past that. The GPS satellites are in semisynchronous
orbit.

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sabalaba
Noisebridge has been doing this since 2010:
<https://www.noisebridge.net/wiki/Spacebridge>.

~~~
gammarator
These are satellites in orbit, not suborbital balloon payloads.

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tenpoundhammer
How long until the paparazzi get their own satellite?

~~~
DigitalJack
I was thinking piratebay.

~~~
adestefan
Balloons/UAVs are more reliable when it comes to communications. Getting a
suitable satellite into orbit that allows for reliable communication is _way_
too expensive.

There was talk of doing a Pirate Bay dirigible at one point.

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zerohp


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ttrreeww
Sooo, a lot more dangerous space trash in the future?

~~~
natosaichek
Cubesats are in general some of the safest / least junky spacecraft in orbit.

There are several factors that influence how much space debris a spacecraft
will generate:

1\. Surface area vs. density - If a spacecraft is large and has lots of floppy
solar panels and things hanging off of it, it's much more likely to be
involved in a collision, and if it is involved in a collision, it's more
likely that it will generate secondary debris dangerous to other spacecraft.

2\. Orbital lifetime - If a spacecraft is in orbit for longer, it's more
likely to be involved in a collision.

Cubesats are usually very dense, with few or no deployable components.
Cubesats are also typically deployed in a low orbit that has a short lifespan
- less than 2 years or so.

There are of course exceptions to both of these rules, but the phonesats are
not.

~~~
johnabowen
Very dense = high ballistic coefficient = longer orbital lifetime

Though I generally agree that CubeSats are relatively safe / low junkyness.

In fact, most (US only maybe?) CubeSats have to demonstrate an orbital
lifetime of less than 25 years to get a frequency allocated. (The FCC
regulating space debris via frequency allocation is an interesting debate for
another thread.)

