Inflatable Heat Shield

In article om,
says...

On 2016-03-12 09:39, Jeff Findley wrote:

Better to leave it where it is until we have all of the bits of
technology, then decide if it is worth it to bring it back.


Unless someone decides to bring it back, the technology won't be
developped to bring it back safely.

Disagree. Much of that tech will be needed to land on Mars.

Out of curiosity, Does Orion have any cargo capacity ? Say they wanted
to attach de-orbit engine and parachites to Hubble, could that come up
on an Orion and have crews EVA to bolt the things on Hubble ?

Not in and of itself, but it is designed to be launched above payloads
on SLS, so that you could launch an airlock/servicing module underneath.
This was proposed long ago by the "Direct" team. It should work fine
for SLS too.

or would the parts have to be shipped separately and parked next to
hubble so that Orion crews could EVA and somehow translate between the
parked parts, Orion and Hubble ?

Nope, SLS is huge, so it can do it in one launch.

I take it SpaceX has the technology to ship the parts up and park next
Hubble ? Or does Hubble lack the space equivalent of an ILS to allow
Dragon to station keep next to Hubble as it does with the station before
being grappled ?

Possibly as a launch on Falcon Heavy (with cargo underneath the Dragon).
More likely as a dual launch with Crew Dragon on Falcon and everything
else on another Falcon or a Falcon Heavy. Would still be cheaper this
way than using SLS. Could possibly launch one Dragon unmanned with the
cargo launch and use it as a nice big airlock.

As Hubble's altitude slowly goes down, does it pose any risk to other
orbiting vehicles such as ISS ? aka: is there some priority to manage
its re-entry, or can it "safely" allowed to decay until low enough that
it re-enters like Skylab did ?

ISS can move out of the way. Uncontrolled reentry is to be avoided at
all costs considering the primary mirror would likely survive reentry.
A bigger risk is orbital debris hitting Hubble and creating even more
orbital debris (not good).

Likely Hubble will be destructively deorbited into the Pacific at the
end of its useful life. It's the safest option.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

In article ,
says...

the last service mission bolted on a docking attachment to allow
remote docking for a deorbit engine.

but rather than deorbit it to a firey end its better to save it for history.

place in higher stable orbit, say 100 years. for future recovery

Orbital debris risk, especially if Hubble gets hit by debris. A debris
hit can create hundreds, if not thousands, of additional bits of debris,
making the orbital debris problem much worse!

Safest option is controlled deorbit into the ocean.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

On Saturday, March 12, 2016 at 4:40:53 PM UTC-5, Jeff Findley wrote:
In article ,
says...

the last service mission bolted on a docking attachment to allow
remote docking for a deorbit engine.

but rather than deorbit it to a firey end its better to save it for history.

place in higher stable orbit, say 100 years. for future recovery

Orbital debris risk, especially if Hubble gets hit by debris. A debris
hit can create hundreds, if not thousands, of additional bits of debris,
making the orbital debris problem much worse!

Safest option is controlled deorbit into the ocean.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

everything in orbit can be hit and cause more debris.

it could be launched into heliospheric orbit if debri creation were really a issue......

if it were up to some posters here indenpence hall and most other historic buildings would of been demolished by now

On Mar/12/2016 4:38 PM, Jeff Findley wrote :
In article om,
says...

On 2016-03-12 09:39, Jeff Findley wrote:

Better to leave it where it is until we have all of the bits of
technology, then decide if it is worth it to bring it back.


Unless someone decides to bring it back, the technology won't be
developped to bring it back safely.

Disagree. Much of that tech will be needed to land on Mars.

You don't need to land large objects on Earth to go to Mars. And landing
on Mars is quite different from landing on Earth, less atmosphere and
less gravity. It isn't obvious that technology developed for Mars
landings would be of any use for this.


Alain Fournier

On Sunday, March 13, 2016 at 1:14:26 PM UTC+13, Alain Fournier wrote:
On Mar/12/2016 4:38 PM, Jeff Findley wrote :
In article om,
says...

On 2016-03-12 09:39, Jeff Findley wrote:

Better to leave it where it is until we have all of the bits of
technology, then decide if it is worth it to bring it back.


Unless someone decides to bring it back, the technology won't be
developped to bring it back safely.

Disagree. Much of that tech will be needed to land on Mars.

You don't need to land large objects on Earth to go to Mars. And landing
on Mars is quite different from landing on Earth, less atmosphere and
less gravity. It isn't obvious that technology developed for Mars
landings would be of any use for this.


Alain Fournier

CLEANING UP EARTH ORBIT

Check it out;

http://inhabitat.com/cleanspace-one-...us-space-junk/

http://www.space.com/24895-space-jun...-concepts.html

http://www.space.com/24325-japan-space-junk-tether.html


Many serious aerospace types are thinking of ways to clean up debris on orbit. One of the most innovative ways uses a large tether that is charged, and interacts with the magnetic field of Earth to accelerate the vehicle and debris, into a parking orbit.

MICRO-SATELLITES AND NANO-SATELLITES

Micro-satellites, and nano-satellites, that are solar powered are of interest. Power and thrust go down as the square of the dimension. Weight goes down as the cube of the dimension. That means power to weight and thrust to weight go up as dimension goes down.

THE POWER OF SMALL

A sphere of silicon 1 meter in diameter has a projected area of 7,854 sq cm and a total area of the sphere of 31,416 sq cm and a volume of 523.6 litres. It intercepts 1,074.4 watts on orbit, and masses 1,178.1 kg. It intercepts 0.9 Watts per kg.

A sphere of silicon 1 centimeter in diameter has a projected area of 78.54 square millimeters and a total spherical area of 314.16 square millimeters. It has a total volume of 0.52 millilitres and masses 1.18 grams. It intercepts 91.2 Watts of sunlight for each kilogram of mass.

Dia cm2 cm2 cm3 Watts grams W/kg

100 7854 31416 523,599 1074.4 1,178,097 0.912
10 78.54 314.16 523.60 10.7441 1178.1 9.120
1 0.7854 3.14159 0.5236 0.10744 1.17817 91.2
0.1 0.00785 0.0314 0.00052 0.00101 0.00177 912

Smaller is more capable if you're dealing with thrust to weight and power to weight from sunlight.

UTILITY FOG

In 1992 Rutgers professor J. Storrs Hall, proposed swarms of nano-fabricated robots to do a variety of tasks. The original proposal was a replacement for a seat belt. Here nanoparticles would coat the interior surfaces of a vehicle and act like an air bag deploying when they detected extreme acceleration, launching against the passengers in a way to hold them in place, dynamically during the acceleration, and disappearing when the vehicle came to a rest. Other applications include detecting the shock wave of a bullet, calculating where it will hit, and if it intersects a person, the foglets deflect the bullet or stop it before it reaches its intended target.

http://www.nanotech-now.com/utility-fog.htm
https://www.foresight.org/Nanomedicine/Swarm.html
https://goo.gl/YdB2VO

Other uses include assembly into anything you like. Consider that all living things are composed of cells. Humans consist of trillions of cells. Trillions of cells smaller than the eye can see, about 230 micons in diameter each, assemble to form all our organs, our brains, heart, muscles, skeletons, eyeballs, ears, etc. Everything we can make with machinery, we can make with swarms of machine cells of similar size.

Top engineering schools are working on the operating systems today that will be used with these machines.

https://www.youtube.com/watch?v=xK54Bu9HFRw
https://www.youtube.com/watch?v=ZXpkG93KzdY

SELF REPLICATING MACHINERY

Self replicating systems are being worked on as sell, including very small and very capable self replicating systems. Leading eventually to a self replicating machine cell.

https://www.youtube.com/watch?v=Pxv4vDMOFCo
https://www.youtube.com/watch?v=zE-HtMsJnBI
https://www.youtube.com/watch?v=mB51gnRfMmc
https://www.youtube.com/watch?v=VTS9O0CoVng
https://www.youtube.com/watch?v=BN-FU8VPoOc

The Human Genome contains 6 billion base pairs that hold 1.5 gigabytes of information. So, this scales what is likely to be needed to produce a self replicating machine of any complexity up to that of a human being.

A Turing tape machine can be replicated on the molecular scale, that has significantly higher data storage capacity than the human genome, and is capable of processing information on a molecular scale. Instead of writing a one or zero on a paper tape, this molecular level Turing tape controls the deposition or retrieval of molecules on a surface which also control the direction and action of the 'read write head'. Something similar to this, but on a far smaller scale than this kinesin molecule;

https://www.youtube.com/watch?v=y-uuk4Pr2i8
https://www.youtube.com/watch?v=R5DqX9vDcOM

WHAT'S IN ORBIT AROUND EARTH?

Now, the Goddard Space Flight Center's tracks 2,271 satellites currently in orbit. Russia orbited the first satellite and has the most satellites currently in orbit, with 1,324 satellites, followed by the U.S. with 658. About 1,100 active satellites, both government and private are in orbit. There are about 2,600 ones that no longer work. In addition there are 20,000 objects tracked that are larger than 10 cm in diameter, and not part of a satellite. There are 500,000 objects larger than 1 cm in diameter and smaller than 10 cm in diameter. There have been 5,210 launch attempts throughout history, and most of these have been successful. A total of 2,250 tons of material are on orbit around the Earth, and 450 tons is active whilst 1,800 tons is inactive.

http://www.popsci.com/now-you-can-se...arth-real-time

WHAT'S IT WORTH?

Region Billions Fracdtion Billions Years Billions

USA.... $11,800.00 0.00140 $16.52 58 $ 958.16
Europe $11,700.00 0.0003 $ 3.51 54 $ 189.54
Japan.. $ 3,700.00 0.0005 $ 1.85 46 $ 85.10
China.. $ 7,300.00 0.0002 $ 1.46 46 $ 67.16
Russia. $ 1,400.00 0.0006 $ 0.84 59 $ 49.56
India.... $ 3,300.00 0.0003 $ 0.99 41 $ 40.59

TOTAL. $39,200.00 ------ $25.17 $1,390.11

About $1.39 trillion was spent putting up 1,800 tons of material. This is $617,777 per kg. Now, this includes all program costs adjusted for inflation based on current rates of spending projected backwards.

Current launch costs are reportedly $6,000 to $12,000 per kg. 1,800 tons at this price has a value on orbit of $10.8 bilion to $21.6 billion.

CLEANING THE ORBIT AS A BUSINESS

Material on orbit, when fashioned into useful products, has more value than the same material when fashioned into useful products on Earth. This spread in value favours space based manufacturing.

VALUE

At $6,000 per kg the 1,800 of abandoned debris on orbit is worth $10.8 billion if it can be;

(1) gathered together,
(2) assembled into a useful satellite.

Since the satellites themselves are uniquely fashioned form materials needed to make satellites, they are ideally suited as the feedstock to build new satellites!

ENERGY

It takes about 40 MJ/kg to process any element down to plasma and reassemble it again using additive manufacturing. Imparting a 2 km/sec delta vee to an object on orbit, to change its orbital parameters, using a 50 km/sec exhaust velocity from an ion rocket, requires that 40.81 grams of material be ejected for each kilogram of material moved in this way. Thus 1,729.4 tons of material can be retrieved from the 1,800 tons of debris on orbit. 70.6 tons of material is ejected at a speed of 50 km/sec. 88.25 terajoules of energy are required to collect all the space debris. An additional 69.18 terajoules is required to reduce the recovered material to elemental plasma and assemble it into new satellites whose designs are beamed up to the collecting swarm. 157.43 terajoules per ton.

RATE

http://www.spacedaily.com/reports/Mo...Years_999.html

About 122 satellites are launched each year, at a cost of $19.4 billion per year massing a total of 734 tons.

A 50% market penetration, means that the 1,800 tons collected will last five years, and in that time additional payloads will be retieved, which means the system will be fully utilized and recover 367 tons each year. About one ton per day. This requires the collection of 157.43 terajoules per day. 1.822 GW. At 20 MW per ton this implies 91.1 tons of the 1800 tons of material, must be fabricated into self replicating machinery that is solar powered.

MACHINE CELL DYNAMICS

At an average density of 2.25 tons per cubic meter, and 20 MW per ton at 80% efficiency, with 1368 W/m2 of sunlight, 1874.8 sq meters of collector area per ton 8,122.2 square meter per cubic meter, implies a 123.1 micron diameter cell, if solid, or a 230 micron cell with 30 micron thick shell. Something on that order to achieve this level of performance. This is 8.54 micrograms per cell. A 300 mm wafer would have 1.7 million cells laid out flat across its surface, and when exposed to sunlight on orbit, it would fold up into a functional cell. It would then consume its carrier craft, which would mass no more than 40 grams per wafer, and it would double every 91.1 days - given the energy levels involved, which includes processing the materials on orbit, and moving them.

So, launching 53 tons into LEO aboard a Falcon Heavy for $61 million, releases a swarm of trillions of cells that grow to 91.1 tons in 10 weeks. Continuing to grow until 1800 tons is processed and removed to its parking orbit, takes 66 weeks.

Satellites are designed and those designs are sent to the cell swarm which assembles into the satellites called for.

Of course, as each satellite is torn apart, it is analysed in exquisite detail, so any satellite processed in this way can be replicated precisely. Furthermore, space debris can be analysed at a microscopic level, to determine the effects of the space environment on the satellite, which can help design newer better satellites.

BEYOND DEBRIS PROCESSING

LUNAR PROCESSING

With 1800 tons of machine cells on orbit, and the ability to process up to 20 tons per day, spacecraft can be sent to the Moon to extract raw materials from the lunar surface. India and China have discovered vast reserves of water near the poles. Water appears more common than previously thought in the solar system. Mercury's polar regions are covered with ice, where the sun doesn't shine. It appears that proton streams from the sun collide with silicates and reduce them to silicon hydrides and water. Some of that water collects in shadowed regions and over geological time, water accumulates.

Thus lighter elements can be extracted from the moon, launched into orbit and made available to the facility described here.

ASTEROID PROCESSING

Passing asteroids cross Earth's orbit every day. Utility fog dispatched to these asteroids using their significant delta vee capabilities, can process these asteroids and return valuable materials to Earth orbit for processing, as well as precious metals to Earth's surface. Ending the process of mining the Earth eventually.

POWER SATELLITES

1800 tons at 20 MW per ton can translate into 36 GW of power. At $0.08 per kWh this translates to $25.6 billion per year. About twice what can be earned from processing materials in space.

TETHERS MADE ON ORBIT

http://ntrs.nasa.gov/archive/nasa/ca...9980048417.pdf

100 tons can be flown to the stratosphere and picked up by a 1000 ton tether system made on orbit from debris. Lowering the size and complexity of launcher.

In article ,
says...

On Saturday, March 12, 2016 at 4:40:53 PM UTC-5, Jeff Findley wrote:
In article ,
says...

the last service mission bolted on a docking attachment to allow
remote docking for a deorbit engine.

but rather than deorbit it to a firey end its better to save it for history.

place in higher stable orbit, say 100 years. for future recovery

Orbital debris risk, especially if Hubble gets hit by debris. A debris
hit can create hundreds, if not thousands, of additional bits of debris,
making the orbital debris problem much worse!

Safest option is controlled deorbit into the ocean.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

everything in orbit can be hit and cause more debris.

Which is why it is important to only keep operating satellites in orbit.

it could be launched into heliospheric orbit if debri creation were really a issue......

It could also be placed in lots of other "graveyard" orbits, but the
Delta V required would be prohibitive. If putting it into such a
graveyard orbit would cost 5x the cost of deorbiting it, who will pay
the difference? What is the cost/benefit of that additional cost?

if it were up to some posters here indenpence hall and most other historic buildings would of been demolished by now

Bull****. Fixing buildings on the ground that people can actually visit
and use is generally far less expensive than trying to "save" a
satellite that does not operate any longer.

Besides, very few people would appreciate the difference between seeing
the Hubble test article that is *already* in the Smithsonian versus the
actual flown Hubble.

You are tilting at windmills Bob.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

In article , says...

On Mar/12/2016 4:38 PM, Jeff Findley wrote :
In article om,
says...

On 2016-03-12 09:39, Jeff Findley wrote:

Better to leave it where it is until we have all of the bits of
technology, then decide if it is worth it to bring it back.


Unless someone decides to bring it back, the technology won't be
developped to bring it back safely.

Disagree. Much of that tech will be needed to land on Mars.

You don't need to land large objects on Earth to go to Mars. And landing
on Mars is quite different from landing on Earth, less atmosphere and
less gravity. It isn't obvious that technology developed for Mars
landings would be of any use for this.

True, landing on Mars is *harder* due to its much thinner atmosphere.

Right now, the biggest US reentry vehicle that is flying is Dragon (v1,
or cargo dragon). Orion has been test flown exactly once. Neither are
big enough to bring Hubble back.

Landing large objects on Mars will require technologies like inflatable
heat shields, which might also be applicable to bringing back Hubble.
Other related tech might also apply.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

On Mar/13/2016 10:58 AM, Jeff Findley wrote :
In article , says...

On Mar/12/2016 4:38 PM, Jeff Findley wrote :
In article om,
says...

On 2016-03-12 09:39, Jeff Findley wrote:

Better to leave it where it is until we have all of the bits of
technology, then decide if it is worth it to bring it back.


Unless someone decides to bring it back, the technology won't be
developped to bring it back safely.

Disagree. Much of that tech will be needed to land on Mars.

You don't need to land large objects on Earth to go to Mars. And landing
on Mars is quite different from landing on Earth, less atmosphere and
less gravity. It isn't obvious that technology developed for Mars
landings would be of any use for this.

True, landing on Mars is *harder* due to its much thinner atmosphere.

Right now, the biggest US reentry vehicle that is flying is Dragon (v1,
or cargo dragon). Orion has been test flown exactly once. Neither are
big enough to bring Hubble back.

Landing large objects on Mars will require technologies like inflatable
heat shields, which might also be applicable to bringing back Hubble.
Other related tech might also apply.

Might is the key word there.

I wouldn't really say that landing on Mars is harder than landing on
Earth. It is different. Some aspects are harder, others are easier. The
slower entry speed and lower gravity on Mars make things easier. A heat
shield suitable for Mars isn't necessarily sufficient for Earth. Landing
legs strong enough for Mars aren't necessarily strong enough for Earth.
You are right, the thinner atmosphere at Mars complicates things a lot.
All in all, I don't know which is the hardest, but technology developed
for one isn't necessarily useful for the other.


Alain Fournier