Reentry

[Rhyshaelkan]

We made it! PERMANENT received the funding it needed. Designed, built and sent out probes. Studied the market to decide what would be most advantageous to get a return on investment. Now we have to bring it home.

Volatiles are needed in orbit or on Luna. No real issues there. Orbit Transfer Vehicles do the job nicely. Iron and nickel are a plenty on Terra. They might not even make the list of what to return from said asteroid. Metals of the platinum group however are needed for so many processes. I will not go into their uses here. That is covered so many times elsewhere.

How do we return them safely Terra-side? It would behoove us to leave the vessel used to transport said good from the asteroid in space. Thus we will not have to launch it again. It might come to the point that we have everything we need to recover precious metals from an asteroid. Except the return device.

Therefore we could design an ablative flower petal heat-shield that could fit snugly inside the Falcon-Heavy 9's faring. Once in orbit(possibly carrying along other goods as space and weight allow) it could unfold to it's final position. Be loaded down and pushed for reentry. All unmanned for maximum cargo. Control thrusters, parachute system.

I am not an engineer. I just like to imagine how things could work ;)

[Boxy]

I was actually thinking about this very subject, and thought I would bring it up. Looks like you've stolen yet another one of my ideas before I have the chance to implement them, you scoundrel you!

What I was thinking we do is get a payload of precious metals (i.e. those most likely to net sizable returns on Earth, such as those in the platinum group you suggested) and create a shell of heatshielded ceramics similar to those found on the Space Shuttle. That way we could just "drop" it to Earth without necessarily having any thrusters on it.

One way to do this is possibly to have it first orbiting the Moon, adjusting orbit for an elliptical escape to Earth, but instead of transferring it to LEO have it go on a collision course with the Indian Ocean. The heatshielding would be useful in this scenario for preventing the precious metal from melting and being dispersed amongst the atmosphere. A secondary system could thereafter dump the ceramic shielding and deploy "floaties" to allow the payload to buoy among the surface.

An alternative plan: fabricate an engine and slap it on the payload. Have it thrust in the opposite direction that it's orbiting. Slowly, it will descend. When it hits the atmosphere, it will slowly burn in the atmosphere like standard re-entry and will therefore need much the same mechanisms as standard re-entry. However, if it is unmanned (as you suggested) it may be possible to withstand much greater accelerations than manned vehicles and therefore it is not necessary to slow before it splashes down.

I really see those as the only two options: ballistic re-entry or orbital re-entry. Thoughts?

[Rhyshaelkan]

I am a pirate like that :D I devour people's intellect.

So my question regards controlled reentry. After thrusters have oriented the shield to the right angle of attack for reentry. Does the shape itself help keep it oriented? Or do thrusters fire occasionally to keep the attitude correct? If it does keep itself oriented by design. It could result in weight savings at launch since less control propulsion would be required.

Depending on where the main base of operation is, will probably dictate into which ocean we would want our craft to return. If said reentry vehicle is containing several thousand pounds of various precious metals... Don't let the pirates know what is going on :P

New York spot price as of 0837 EDT 28072009 for platinum $1214 per oz. Sell!

We know the resources are out there. Another big thing to consider is how rapidly can you extract the minerals you want.

[Boxy]

Well, I know that the Space Shuttle needs attitude thrusters because if they tip down, they risk a ballistic collision with Earth, and if they tip up they risk bouncing off the atmosphere. Re-entry is a bitch of an engineering problem when you have to stop it gently for humans to walk out, instead of being scraped off the tarmac with a pancake flipper.

For a ballistic reentry plan, you could shape it like a bullet and use a tug to spin it. A spinning bullet, for example, will retain its ballistic stability better than a round one. The only problem with this is that a bullet has less drag than, say, a raindrop which has a rounded front.

Unfortunately, it's hard to slow down something that's going fast enough to orbit the Earth or to escape the Moon. Even if it's in LEO, it's at hypersonic speeds, and you can't exactly parachute down. Airbraking is possible to some degree, but when you're in the hypersonic stage you risk producing torque on your space freighter and bouncing it straight off the atmosphere.

If we go with SpaceX, their main base of operations could potentially be in the South Pacific. We could splash down there pretty easily and recover the payload without much difficulty. I suggested the Indian Ocean specifically because (A) there's an exceptionally low chance of accidentally hitting a population center, and (B) nobody who would want to pirate our payload would be hanging around in the South Indian Ocean. Malaysians and Somalis, maybe, but the South Indian Ocean isn't exactly a hotspot for marauders looking for literally tons of gold and platinum.

If Eros is typical of stony meteorites, then it contains about 3% metal. With the known abundance's of metals in meteorites, even a very cautious estimate suggests 20,000 million tonnes of aluminium along with similar amounts of gold, platinum and other rarer metals.
(source) (http://news.bbc.co.uk/2/hi/science/nature/401227.stm)

To recoup the losses of a $500 million USD launch to Eros (just plugging a number in), we would have to sell 13 tons of platinum. It makes me happy to think of how much this is going to flood the minerals market. Can you imagine gold being as cheap as copper? The mind simply boggles at the concept.

[Rhyshaelkan]

I enjoyed watching all the videos at SpaceX. Including the Dragon reentry. Which raised my question as to whether the design itself helps to stabilize it during reentry.

A big pile of precious metals does not have to worry about vomiting. So you could put the reentry vehicle into a mild spin to keep it from tumbling.

Many things to consider during the design process. All of which will minimize launch weight and maximize return payload weight. Thus leading to faster returns on investment.:D

[Boxy]

...

Let's build a massive platinum bullet. You know you want to :D

[Rhyshaelkan]

::Rhy ponders::

At current prices 13*2250*16*$1220=$570,960,000

Not sure if this is so pretty as I thought. For how long will it take to extract 13 metric tons of platinum.

However if the design is right. You have already put your mining equipment up. Which could also include an OTV. From then on all you are launching would be the reentry vehicle. Unless that could be made in orbit. But I am sure that would require another solar furnace and mold to fashion the ablative heat shield.

Once again I think it best to get manufacturing on Luna to help support mining efforts. Luna could provide the heat shield, AlLox fuel. From then on nothing needs to come up. It is payday after payday.

[Boxy]

Unfortunately, that just increases startup costs. All in all it makes me think that our best bet for long-term asteroid mining is to build an industrial complex somewhere that includes a shipyard to build single-use reentry vehicles.

I vote that NASA brings industrial engineers with them when they establish a lunar base, so that they can machine-shop anything they need.

Oh, yeah -- and start building colonies. The surface of the Moon has the same area as about a quarter of the total landmass of Earth. If anything, it would reduce population pressures by at least 4/5, if we were looking strictly at land usage. I imagine that if we manufacture an atmosphere around the Moon that it would fill up some of the craters with some pretty impressive lakes and seas.

[Rhyshaelkan]

Certainly many things to weigh. How much would it take to set up a fabrication complex in LEO, Luna, or at the asteroid of choice.

Thus I go back to Luna for reason pointed out by John Hunt. Kill two birds with one stone. Lay the ground works of an self-supportive "ark", while at the same time cutting dependence on Terra launched fuels, heat-shield, etc.

In addition, though this might be my personal opinion. After watching those silly astronauts on NASA Tv doing work on this and that. I think I would want some definite gravity under my feet.

Yes I would like to be humming a tune while doing some Lunar work in 10-15 years.

All depends on financing how quickly things could move. Look at how rapidly the space program moved back in the late 50's to late 60's. Huge ground was covered. And they did not have Autocad or other fantastic tools for physics modeling.

I better hush before I get carried away again. This stuff really burns in my heart.

[Phenix]

Did you thought before reentry if any of the material shoud be analyzed in a orbital quarantine zone ?

[Rhyshaelkan]

For what would we be quarantining? I can only think of standard NBC stuff. So for that...

The probes sent out would probably have a Geiger counter. No issues with radioactivity there.

If at all possible we would not be returning ore. We would be returning cast bars of precious metals( why pay for the shipping cost of stone if you can refine the product on site and return more of the quality goods). Any chemical toxicity would be detected and burned while firing. No issues there.

If we are returning volatiles. They could be inspected to make sure they are not returning any possible biologicals. Though the detection of such would be far more valuable than not. No issues there.

[Phenix]

Yes, I do think the same concerning the volatiles and ice. How about confining ice and volatiles at conditionned warehouse before scientist confirms life forms? It would be invaluable.

[Rhyshaelkan]

However launching into space costs alot. As "cool" as it would be to find life. It would do nothing to help the economy. Oh institutes would pay for samples undoubtedly. But they might also say it is humanity's right to study extra-terrestrial life. And take our hard earned efforts for no return.

Mark Prado needs to chime in from time to time since PERMANENT is his baby ;) no insult to Mark though.