Sedna Probe?

[Streetwind]

They'd have to restart the cancelled development program on those. (It had huge cost and schedule overruns.)

[fredinno]

2 hours ago, Streetwind said:

They'd have to restart the cancelled development program on those. (It had huge cost and schedule overruns.)

Those were stifling RTGs. ESA is developing Amercium RTGs.

[Streetwind]

Well, the stirling RTGs were supposed to be able to run on Americium too. I wasn't aware of a separate program by ESA, will go look it up.

[pathmage]

What about DEEP IN?

[fredinno]

2 hours ago, pathmage said:

What about DEEP IN?

wtf is DEEP IN?

[cubinator]

On 1/21/2016 at 8:32 PM, Spaceception said:

A "Plain old Jupiter gravity assist" won't work, unless you want to wait ~30 years, we'll have to use a full-blown Nuclear reactor and VASIMR thruster, to shorten the time from ~30 years, to 10 years

Well, if we did an impact trajectory with Jupiter at just the right angle, then timewarped hard, we might be able to clip the probe through the surface and cut the transfer time down to a few weeks or less. It'd be risky though, if it doesn't timewarp enough it could explode before getting through.

Edited February 24, 2016 by cubinator

[fredinno]

22 minutes ago, cubinator said:

Well, if we did an impact trajectory with Jupiter at just the right angle, then timewarped hard, we might be able to clip the probe through the surface and cut the transfer time down to a few weeks or less. It'd be risky though, if it doesn't timewarp enough it could explode before getting through.

This is IRL, not KSP. Good try though.

[Streetwind]

11 hours ago, fredinno said:

wtf is DEEP IN?

https://www.nasa.gov/feature/deep-in-directed-energy-propulsion-for-interstellar-exploration
http://www.space.com/32026-photon-propulsion-mars-three-days.html
"Directed Energy Propulsion for Interstellar Exploration"

Basically, a proposal for driving spacecraft to relativistic speeds with large orbital lasers. The idea has existed in sci-fi literature for decades, but now a company says they could make it work, and NASA has given them some grants. They say they can get a 220kg probe to Mars in three days. Of course, they neglect to mention how said spacecraft would slow itself down for Mars orbit insertion, how the orbital laser platform obtains its energy, or how said platform remians in orbit while essentially running a gigantic photon drive for days at a time.

In other words, this is not something we need to take seriously right now - as far as practical use goes, it's about as far as the Cannae Drive. A potentially interesting development, but not a serious contender for pratical implementation in the near future.

Edited February 25, 2016 by Streetwind

[p1t1o]

8 hours ago, Streetwind said:

https://www.nasa.gov/feature/deep-in-directed-energy-propulsion-for-interstellar-exploration
http://www.space.com/32026-photon-propulsion-mars-three-days.html
"Directed Energy Propulsion for Interstellar Exploration"

Basically, a proposal for driving spacecraft to relativistic speeds with large orbital lasers. The idea has existed in sci-fi literature for decades, but now a company says they could make it work, and NASA has given them some grants. They say they can get a 220kg probe to Mars in three days. Of course, they neglect to mention how said spacecraft would slow itself down for Mars orbit insertion, how the orbital laser platform obtains its energy, or how said platform remians in orbit while essentially running a gigantic photon drive for days at a time.

In other words, this is not something we need to take seriously right now - as far as practical use goes, it's about as far as the Cannae Drive. A potentially interesting development, but not a serious contender for pratical implementation in the near future.

 

Also I can see some people having a problem with someone putting a multi-megaWatt (or higher) laser in orbit...

For reference, solar irradiance at 1AU is 1.36kW/m2, producing a radiation pressure of 9uN/m2 (thats microNewtons).

Meaning (for blackbody radiation) you need 149.89 MW / N

Its not my favorite method of exotic propulsion, especially as its efficiency rapidly tails off with distance.

There does exist a method of enhancing the efficiency of this system if the probe can reflect the laser accurately enough back at the station - the station can then re-reflect it back, rinse and repeat.

 

Edited February 25, 2016 by p1t1o

[fredinno]

6 hours ago, p1t1o said:

 

Also I can see some people having a problem with someone putting a multi-megaWatt (or higher) laser in orbit...

For reference, solar irradiance at 1AU is 1.36kW/m2, producing a radiation pressure of 9uN/m2 (thats microNewtons).

Meaning (for blackbody radiation) you need 149.89 MW / N

Its not my favorite method of exotic propulsion, especially as its efficiency rapidly tails off with distance.

There does exist a method of enhancing the efficiency of this system if the probe can reflect the laser accurately enough back at the station - the station can then re-reflect it back, rinse and repeat.

 

Yeah, I can see this thing being a massive expense to operate and build to propulse a spacecraft at sedna distances....

A bigger problem is slowing down- you know, to get better pictures. A sedna probe may just be traveling too fast.

[p1t1o]

55 minutes ago, fredinno said:

Yeah, I can see this thing being a massive expense to operate and build to propulse a spacecraft at sedna distances....

A bigger problem is slowing down- you know, to get better pictures. A sedna probe may just be traveling too fast.

Well, I mean, you could put engine+fuel onboard the probe to slow down, you still save on fuel on the outbound leg, but it eats heavily into your margin. It definitely does seem like an awfully big and powerful and expensive complex just for that.

The number of probes you'd have to send so that you break even on launch costs would be insane.

[Guest]

Definitively an interesting mission. 

[Scientia1423]

I heard the Buran's Energia are actually going to become a rocket in the future. So shove the 2020 version of the New horizons probe onto the carrier with tons of SRB's stowed away with an Amercium RTG and Four ion thrusters to put it into a polar Sedna orbit.

Here is some Info on the Energia:

It can go all the way to Geostationary orbit; It tried to launch a satellite into orbit but failed to decouple the stages; It's completely LF/O Mix and will not blow up like challenger; It has 4 LF/O boosters... So it seems feasible to reach Sedna with a plan like this

Edited February 26, 2016 by Scientia1423

[DerekL1963]

1 hour ago, Scientia1423 said:

I heard the Buran's Energia are actually going to become a rocket in the future.

It's not.

[p1t1o]

Just saw [on wikipedia] this schematic of how a light-propelled craft could potentially be slowed for rendezvous at its destination.

Doesn't approach the problem of the inverse square law but its something.

[Scientia1423]

7 hours ago, DerekL1963 said:

It's not.

https://en.wikipedia.org/wiki/Energia#Revival if not then oh well.

[DerekL1963]

16 minutes ago, Scientia1423 said:

https://en.wikipedia.org/wiki/Energia#Revival if not then oh well.

The source for that claim, Space Daily, is...  not entirely reliable.  And if you've paid any attention to space news over the last decade, you'll have noted that the Russians release bold plans to make bold plans on practically a daily basis.

[p1t1o]

The Space Daily article isn't exactly full-on for Energia revival either, just that they really would like more space stuff and, boy, wasn't energia great?

Given that a great deal of energia/buran hardware has either been sold, scrapped or just left to rot in the desert (google image search "energia buran scrap"), seems unlikely that in 2020 they would revive a 30 year old platform instead of something using more modern technology.

[Scientia1423]

5 minutes ago, DerekL1963 said:

The source for that claim, Space Daily, is...  not entirely reliable.  And if you've paid any attention to space news over the last decade, you'll have noted that the Russians release bold plans to make bold plans on practically a daily basis.

Russians appear to be aspirational, but then again too much isn't a good thing. Ah well, at least I tried...

[fredinno]

On 2/25/2016 at 11:44 AM, p1t1o said:

Well, I mean, you could put engine+fuel onboard the probe to slow down, you still save on fuel on the outbound leg, but it eats heavily into your margin. It definitely does seem like an awfully big and powerful and expensive complex just for that.

The number of probes you'd have to send so that you break even on launch costs would be insane.

I think it will only become possible once solar sails can be built big enough, then use the on-board fuel to decelerate.

19 hours ago, Scientia1423 said:

I heard the Buran's Energia are actually going to become a rocket in the future. So shove the 2020 version of the New horizons probe onto the carrier with tons of SRB's stowed away with an Amercium RTG and Four ion thrusters to put it into a polar Sedna orbit.

Here is some Info on the Energia:

It can go all the way to Geostationary orbit; It tried to launch a satellite into orbit but failed to decouple the stages; It's completely LF/O Mix and will not blow up like challenger; It has 4 LF/O boosters... So it seems feasible to reach Sedna with a plan like this

Yeah, SLS will be operational by then, and it'd almost certainly be cheaper just to use THAT instead of spend a ton of money building a new upper stage for Energia to get the probe to Sedna.