Could Dawn spacecraft be returned to Earth?

Just curious. Not saying it would be good idea for this mission or not. But seems like if it had enough fuel it could be sent back to Earth, repaired, refueled and then sent on more missions? Why don't we do more of that? Seems like the probes we send out are durable enough to do round trips.

Not on its own, but in theory an Orion crewed spacecraft could recover it. (There's still the long term radiation problem to solve.)

"Earth" should be funding dozens if not hundreds of new probes a year.

I think the expense of having probes return to earth would instantly rule it out to be honest, but that's not the main problem I don't think.
The logistics involved in doing it would be huge. To have it flying around space, getting it to turn around and then making it land somewhere it an be picked up would be hard, but not impossible.

It's probably cheaper to send out something that will last a couple a couple of years, while new technology comes out to launch something even better.

a reply to: Xeven

Fuel..... It is the end all of current space exploration.

It costs a lot more to send more fuel, because that is more weight at launch, and more fuel spent too carry return fuel.

It would take many times more fuel to go to mars and return than to just go to mars.

ETA-though with the new ion drives.... It could be a possibility in the near future!

Not a good idea. RTGs are used in deep space to heat and power space craft components. Once activated they become highly radioactive, as does the whole craft.

RTGs and radioactive contamination

originally posted by: Xeven
Just curious. Not saying it would be good idea for this mission or not. But seems like if it had enough fuel it could be sent back to Earth, repaired, refueled and then sent on more missions? Why don't we do more of that? Seems like the probes we send out are durable enough to do round trips.

Skip this.

a reply to: rhynouk

Seems like the most cost thing is to put stuff up there to begin with. You could point say Dawn toward an Earth encounter relatively cheaply. Even if it took 20 years to return the materials could be recovered, electronics and sensors replaced on space station and then sent back out. You would save money, I would think, by not having to sent the heavy structures and shielding back up into orbit each time.

We also should consider sending material to a recover point rather than burning it up in the atmosphere. Some day humans could use the materials for other things. It could be smelted into new structures or even crashed onto the moon where having Aluminum to melt and create new things with will be a gold mine to anyone trying to build a colony there.

All those Rocket parts that we just allow to burn up could be useful as underground shielding or storage on the moon. That big Shuttle fuel tank for instance if crashed on the moon might just provide material to use to build structures for storage.

Once the Lockheed small Fusion Reactor comes online you can send up Robotic cleaners to pick up old junk in orbit, smelt it and then launch it toward the moon for reuse. Imagine a Robot craft that captures, smelts and then builds stuff ala printing for building a large space station in orbit. Might take 20 years but future man would appreciate our efforts.

Botoom line is we are wasting a lot of material that could be used to build a space infrastructure that would not need to be launched at great expense from the ground.

It's simply not that economical to recover deep space probes at the moment. However if they ever figure out and start producing Star Trek style spaceships then someday they'll probably send some out to recover all the probes they sent out in the past. Assuming they're not dangerously radioactive and can be tracked down.

originally posted by: Xeven
a reply to: rhynouk

Seems like the most cost thing is to put stuff up there to begin with. You could point say Dawn toward an Earth encounter relatively cheaply. Even if it took 20 years to return the materials could be recovered, electronics and sensors replaced on space station and then sent back out. You would save money, I would think, by not having to sent the heavy structures and shielding back up into orbit each time.

We also should consider sending material to a recover point rather than burning it up in the atmosphere. Some day humans could use the materials for other things. It could be smelted into new structures or even crashed onto the moon where having Aluminum to melt and create new things with will be a gold mine to anyone trying to build a colony there.

All those Rocket parts that we just allow to burn up could be useful as underground shielding or storage on the moon. That big Shuttle fuel tank for instance if crashed on the moon might just provide material to use to build structures for storage.

Once the Lockheed small Fusion Reactor comes online you can send up Robotic cleaners to pick up old junk in orbit, smelt it and then launch it toward the moon for reuse. Imagine a Robot craft that captures, smelts and then builds stuff ala printing for building a large space station in orbit. Might take 20 years but future man would appreciate our efforts.

Botoom line is we are wasting a lot of material that could be used to build a space infrastructure that would not need to be launched at great expense from the ground.

Because the extra fuel needed to get just the giant orange shuttle tank to the moon, would require two more giant orange field tanks worth of fuel.

There is a reason these parts fall off of launch vehicles, you save weight thus fuel....

How do you not understand this?

Edited because of spell check.

After you solve all the other problems with something like this...what you get back is obsolete technology, not quite good enough to send back out...so your entire "return" becomes moot.

a reply to: intrptr

Dawn doesn't use an RTG, I don't think. IIRC, it is solar.
But, Dawn was never designed for re-entry into the atmosphere nor docking with another craft outside of it. With enough fuel, it would probably be possible for it to return to some sort of a Earth orbit, but we couldn't really do anything with it past that. We don't have the Shuttles to fly to it and grapple it into a cargo bay anymore.

Indeed, according to NASA, Dawn is equipped with a 1.3kw solar array for power.

a reply to: pfishy

Dawn doesn't use an RTG, I don't think. IIRC, it is solar.

Too far from the Sun to use solar panels and batteries won't last for the duration of the mission.

They used an RTG for Dawn.

Search

originally posted by: Aleister
"Earth" should be funding dozens if not hundreds of new probes a year.

^^

THIS!

originally posted by: Xeven
Just curious. Not saying it would be good idea for this mission or not. But seems like if it had enough fuel it could be sent back to Earth, repaired, refueled and then sent on more missions? Why don't we do more of that? Seems like the probes we send out are durable enough to do round trips.

Here is the answer to your question.

In theory, yes, if it had enough fuel onboard, Dawn could be sent back to Earth.

However what would be the point? If it had enough fuel to redirect itself towards Earth and decellerate to enter a service orbit then it would have the fuel to go on to explore something else further out so why not just redirect it there?

Remember, Dawn's first target was Vesta. It is at Ceres now. If it had enough fuel it could visit other places in the solar system as well.

originally posted by: Xeven
a reply to: rhynouk

Seems like the most cost thing is to put stuff up there to begin with. You could point say Dawn toward an Earth encounter relatively cheaply. Even if it took 20 years to return the materials could be recovered, electronics and sensors replaced on space station and then sent back out. You would save money, I would think, by not having to sent the heavy structures and shielding back up into orbit each time.

You realize how quickly technology changes right?

In 20 years Dawn would be obsolete. And no, it would not be cheaper to send it back for servicing because you're spending fuel to come back to Earth rather than go somewhere else to learn something new.

So you spend twice as much fuel and take twice as much time to do the same thing as launching a newer probe.

a reply to: intrptr

And it's not a matter of 'activating' an RTG. You can't just turn on radioactive elements. They (the RTGs) are radioactive at the point of assembly, as are all the fuel elements from their creation in a reactor unail they have fully degraded into their stable decay products. But the rest of the craft utilizing them isn't going to become radioactive unless the fuel containment of the RTG is breached.

a reply to: intrptr

Your link is for the New Horizons probe, not Dawn. And New Horizons did indeed use an RTG. But at an average distance of 3 AU from the Sun, Dawn does indeed use solar panels. The link you provided about RTGs in the first place lists every one we have sent to space and which missions they were on. Dawn is not listed there.

Here ya go.
JPL/DAWN

a reply to: pfishy

Sorry, got the two mixed up. My bad. I was talking about New Horizons which utilizes an RTG for electrical power. This thread is about Dawn.

Big Solar panels.

BTW, love the 911 fireball images in your avatar.

originally posted by: intrptr
Not a good idea. RTGs are used in deep space to heat and power space craft components. Once activated they become highly radioactive, as does the whole craft.

RTGs and radioactive contamination

I don't think you have read your own link, as it says that there is only a possibility/risk of radioactive contamination.

RTGs pose a risk of radioactive contamination: if the container holding the fuel leaks, the radioactive material may contaminate the environment.

For spacecraft, the main concern is that if an accident were to occur during launch or a subsequent passage of a spacecraft close to Earth, harmful material could be released into the atmosphere; therefore their use in spacecraft and elsewhere has attracted controversy.[21][22]

However, this event is not considered likely with current RTG cask designs.

So there.