MICROSATELLITES; how small? How cheap?

"Brad Guth" wrote in message
oups.com...
Could a microsatellite be configured for surviving a 2.4 km/s lunar
impact, such as impacting into a great deal of moon-dust?


I think this will be your problem more than anything else.
That speed is nearly 5400mph, equivalent to more than twice the maximum
speed of the SR-71 Blackbird. The kinetic energy of the microsatellite is a
little under 3MJ per kg. Even if the satellite were made of solid titanium,
the heat released would be enough to vapourise all of it.

I don't really think this sort of lithobraking is practical on the moon.

Henry

Henry Hallam,
Thanks for all the good info.

Not that surviving impact is essential, although I'm also thinking of a
spin-deployed large area chute.

Thus in addition to whatever our NASA officially stipulates as lunar
atmosphere, how about such efforts taking advantage of a good amount of
sodium breaking, then of Argon and several other element breaking prior
to taking advantage of the final layer of Radon breaking before
becoming thick moon-dust breaking?

How about a CNT/basalt composite nose/shell?

Besides, all that needs to survive should be less than a kg out of 10
kg to start with.

Brad Guth

In sci.space.policy Henry Hallam wrote:

"Brad Guth" wrote in message
oups.com...
Could a microsatellite be configured for surviving a 2.4 km/s lunar
impact, such as impacting into a great deal of moon-dust?


I think this will be your problem more than anything else.
That speed is nearly 5400mph, equivalent to more than twice the maximum
speed of the SR-71 Blackbird. The kinetic energy of the microsatellite is a
little under 3MJ per kg. Even if the satellite were made of solid titanium,
the heat released would be enough to vapourise all of it.

I don't really think this sort of lithobraking is practical on the moon.

However.
2.4Km/s (moon escape) is a relatively small solid rocket.
2.2Km/s (or so) spin-stabilised rocket stage, triggered at the optimum point.
Then another 400m/s stage, with thrust termination, and the thing engineered
to sustain an impact of maybe 30m/s.

It occurs to me that the easiest way for a truly micro-scale lander/crasher
to determine altitude would be inertial navigation plus several wide-angle
cameras, and a gig or several of storage of the moons features.
To avoid the power use and bulk of a laser or other ranger.

Ian Stirling;
2.4Km/s (moon escape) is a relatively small solid rocket.
2.2Km/s (or so) spin-stabilised rocket stage, triggered at the optimum point.
Then another 400m/s stage, with thrust termination, and the thing engineered
to sustain an impact of maybe 30m/s.

It occurs to me that the easiest way for a truly micro-scale lander/crasher
to determine altitude would be inertial navigation plus several wide-angle
cameras, and a gig or several of storage of the moons features.
To avoid the power use and bulk of a laser or other ranger.

Thanks much for all of the impact survival considerations. However, of
whatever if anything survives lunar impact would certainly be darn nice
but, surviving isn't exactly priority No.1

Secondly; I'm thinking there's a bit more to that lunar atmospheric
density than meets the eye. Thus aerobreaking might not be all that
insurmountable. Even if arriving at 300 m/s as going deep into that
thick and nasty moon-dust that shouldn't represent more than 5 g/cm2
worth of surface-tension, and thereby shouldn't be all that probe
lethal of a landing if the CNT/basalt composite hull isn't vaporised in
the process.

At well above the lunar deck there could be an atmospheric density
that's populated at greater than 1e6 atoms/cm3, whereas the final
near-surface layer of Radon(Rn222) combined with the likely amounts of
Argon, CO2, Sodium and even touches of Xenon and Krypton as substantial
secondary elements could actually impose a rather substantial
aerobreaking alternative for such a 1/6th gravity environment. A vast
crater pond of that that moon-dust shouldn't be worth 1% as hard as
water.

Brad Guth

In sci.space.policy Brad Guth wrote:
Ian Stirling;
2.4Km/s (moon escape) is a relatively small solid rocket.
2.2Km/s (or so) spin-stabilised rocket stage, triggered at the optimum point.
Then another 400m/s stage, with thrust termination, and the thing engineered
to sustain an impact of maybe 30m/s.

It occurs to me that the easiest way for a truly micro-scale lander/crasher
to determine altitude would be inertial navigation plus several wide-angle
cameras, and a gig or several of storage of the moons features.
To avoid the power use and bulk of a laser or other ranger.

Thanks much for all of the impact survival considerations. However, of
whatever if anything survives lunar impact would certainly be darn nice
but, surviving isn't exactly priority No.1

Secondly; I'm thinking there's a bit more to that lunar atmospheric
density than meets the eye. Thus aerobreaking might not be all that
insurmountable. Even if arriving at 300 m/s as going deep into that

The atmospheric density is well known.
It's essentially bugger-all, and makes pluto look dense.
Aerobraking is in principle possible - but you'd be looking at something
more like a solar sail than a heatshield.
And you're not going to get high decelleration, or low terminal speeds.

Ian Stirling; The atmospheric density is well known.
Could you please be just a little more specific?

That "density is well known" is supposedly well known by whom, and/or
by way of what hard-science instruments?

All that I can find is what's published within your NASA/Apollo pagan
bible, or perhaps it their koran, as having been based upon evidence
exclusions and those conditional laws of physics.

Brad Guth

In sci.space.policy Brad Guth wrote:
Ian Stirling; The atmospheric density is well known.
Could you please be just a little more specific?

That "density is well known" is supposedly well known by whom, and/or
by way of what hard-science instruments?

All that I can find is what's published within your NASA/Apollo pagan
bible, or perhaps it their koran, as having been based upon evidence
exclusions and those conditional laws of physics.

The apollo experiments were not great.
However, they do set a very low upper bound.
Do you have some reason to believe they are incorrect?

Ian Stirling wrote:
[...]
The apollo experiments were not great.
However, they do set a very low upper bound.
Do you have some reason to believe they are incorrect?

Ian, you responding to Brad Guth.

/dps

Ian Stirling,
Other than some of the science of what had been robotically obtained
from orbit, that which is believable because it falls within the
regular laws of physics, such as the extremely dark and deeply
rich/colorful albedo worth of an extremely dusty moon, as for otherwise
yes I do seem to have a wee bit of a problem with such a nearby orb
that's supposedly so chuck full of nifty elements, as for that nicely
reactive object having such a pathetic 3e-15 bar worth of an atmosphere
that's supposedly represented by all of 2e5 atoms/cm3, along with no
mention of sodium solids nor sodium gas, as well as nothing with regard
to Radium(Ra226) and of its Radon(Rn222) gas existing within any of
those numbers.

Where the heck did all of the lunar Radium(Ra226) go?

As I've said before; it's too bad that after 4 decades and counting
that the likes of yourself, others and I still haven't access to one
interactive science worthy instrument that's sharing information as to
the lunar surface and daytime/nighttime atmospheric environment.

Perhaps China will soon accommodate all of our needs before LUNAR-A or
my small/micro exploratory satellite probes deliver the badly needed
information as to the raw lunar environment.

Brad Guth

snidely,
You're telling "Ian Stirling" what he/she can or can not do?

Is that your MI6/NSA~CIA usenet 'E-men in BLACK' job?

Brad Guth