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Posted by: qraal May 9 2016, 09:18 PM

Speaking of Mike Brown and his planets, if the proposed Planet IX is confirmed, then it's likely to be about 700 AU away. That's a 200 year journey at "Voyager" speed (~3.5 AU/year), so we'll need to go significantly faster.

For historical precedent there's the Thousand AU mission design from the late 1980s, which used a SNAP powered ion drive to push a probe to ~20 AU/year. Waiting 50 years for major data return seems excessive, so I'd think a 20 year max travel time, and preferably a 10 year travel time, should be in the minimum specifications.

The main propulsion options IMO are an extreme Oberth Maneuver, with a very high thrust system at perihelion; a high performance Solar-Sail; an E-Sail, and - a bit more speculative - a laser-push by the proposed Starshot Array.

Anything missing?

Posted by: Phil Stooke May 9 2016, 09:38 PM

I think the Starshot approach is ideal. Think of it as the Pioneer 10 to Starshot's Voyager - proof of concept, and if they can't make it work there is really no point trying for a star. But if it does work, a series of them would allow a pretty good initial characterization of the planet (if it exists). The first might only be a quick survey of the planet, looking for moons or rings, or getting phase data. Then another could be directed closer in to get better images of the planet and a moon or two. The data collection strategy at the star is being tested as well as the propulsion.

Phil

Posted by: HSchirmer May 10 2016, 02:22 AM

One intriguing thing, a very smart but subtle aspect a laser-based lightsail propulsion system-
The technological advances to laser driven propulsion on earth are communicated to a spacecraft at 700 au in a matter of 4 days.

So, the technology advances can be earthbound, e.g. improved lasers, focusing, mirrors and power generation;
but the effect of those propulsion upgrades to the lasers reach the spacecraft at the speed of light.

Posted by: nprev May 10 2016, 05:09 AM

MOD NOTE: Please review and be mindful of rule 1.9 before posting in this topic.

Posted by: qraal May 10 2016, 08:06 AM

To review:

1.9 Other subjects that are banned here include: Pluto's planethood; conspiracy theories; sci-fi engineering; "new physics"; pseudoscience.

...which hopefully we can keep this topic to real near-term engineering options.

Posted by: HSchirmer May 10 2016, 01:36 PM

And to put a bookmark about current engineering:

Lasers- current US Navy laser is solid state 30kW (XN-1 LaWS on USS Ponce),
contracts are out to develop 150kW versions to be aircraft based.

Railguns -current US Navy guns fire 23 pound rounds at mach 7, (escape velocity at earth's surface is around mach 33)
Sea trials are supposed to start aboard USNS Millinocket.


File:Laser Weapon System aboard USS Ponce (AFSB(I)-15) in November 2014 (05).JPG
File:One of two electromagnetic railgun prototypes on display aboard joint high speed vessel USS Millinocket (JHSV 3) in port at Naval Base San Diego on July 8, 2014. US Navy photo.

Posted by: JRehling May 10 2016, 04:11 PM

Here's a proposal for a solar sail craft that would attain a velocity of 400 km/s, which is 1 AU every 4 days. That could reach a distance of 1,000 AU in about thirty years. That would provide the necessary specs for this and many other objectives.

The strategy is to put a spacecraft into an orbit that brings it close to the Sun, then open the solar sails at that time. I don't know if the specifics are in order, but the general principles seem sound. It might be the cheapest way to achieve a certain range of velocities.

https://arxiv.org/pdf/physics/0701073.pdf

Posted by: qraal Jul 20 2016, 09:46 AM

Greg Matloff has explored this conceptual landscape for 40 years, with some interesting figures if highly reflective graphene can be manufactured in large amounts. Alternatively, a Beryllium "pillow" sail could achieve similar performance to Bolonkin's idea.

Bolonkin's idea suggests an interesting hybrid - the solar-electric sail - which JAXA has been exploring. But, of course, Goddard suggested it first way back in c.1918 or so.

Posted by: Julius Jul 20 2016, 11:44 AM

Does the recent discovery of a new KBO help or disprove the existence of Planet 9 and if yes, does it in any way help with better predicting it's current location more accurately?

Posted by: Floyd Jul 20 2016, 04:24 PM

Julius, that question was also asked in the other thread. The answer is maybe... Michelle Bannister gives a great discussion of what they found in the survey that turned up the new KBO. I highly recommend the video.

Posted by: nprev Jul 20 2016, 08:36 PM

MOD NOTE: The title of this topic has been changed because there have been frequent brushes with rule 1.9, specifically regarding the status of Pluto. Reminder that this rule exists to prevent endless, invariably emotional debates that have no scientific relevance. Such squabbling significantly disrupts the civil tone of the Forum, and therefore will not be permitted.

Please refer to the hypothetical "new" outer planet as something other than "Planet 9" from now on. FWIW, I'm going to call it "HOP" for hopefully obvious reasons. Thanks!

Posted by: Explorer1 Jul 20 2016, 11:19 PM

It's too bad Planet X and Tyche already have such established connotations; they would be ideal monikers for an object that remains hypothetical.

Posted by: HSchirmer Jul 21 2016, 05:38 PM

Ah, now I understand what you're focused on. Ninth versus Tenth planet.
Eh, can we crib from Dune, call them IX and Planet X without running afoul? ("there are many interesting machines on IX")
Apocryphal - Dan Quale, "I've always been a big fan of Malcolm the tenth"

IIRC, the orbital ejection simulations suggest that the hypothetical planet with the 700 AU aphelion IS the 7th planet,
e.g. just outside the orbit of Saturn, but it was forcibly relocated due to resonances.
Does that make it Seven of Nine? Or "the planet formerly known as seventh" (insert quasi-astrological prince symbol)

As to the current 7th planet, do we just call it "George"? http://science.nasa.gov/science-news/science-at-nasa/2006/11apr_george/

Apocryphal
- 1781 English astronomer William Herschel names the 7th planet "Georgium Sidus" after "your highness", English King George III,
- 1781 noted scientific wit Benjamin Franklin names the 7th planet "Uranus", based on the Colonial name for English King George III.

Posted by: nprev Jul 21 2016, 10:10 PM

Alright, everyone, I know this is confusing and may seem a bit petty...but we got reasons. Call it what you will, but leave numbers out of it, please; thanks!

Posted by: qraal Aug 23 2016, 08:50 PM

Lorenzo Iorio, the gravitational dynamics researcher, has a melliflous name for the outermost solar planet - Telisto.

Maybe I should have started the thread with that name.

A recent NIAC funded study is of relevance - the Heliopause Electric Rapid Transit System (HERTS) which uses an Electric Sail (E-Sail) to throw a New Horizons class probe into a 10 year trajectory to 100 AU. Of course to reach Telisto a mission time of ~70 years would be required, thus something with a bit more oomph is required. That's the original motivation for the OP.

Posted by: mcaplinger Aug 23 2016, 10:00 PM

I had to read https://arxiv.org/abs/1512.05288 to understand what this meant, and frankly, I don't think the author has the standing to name this object.

http://knowyourmeme.com/memes/stop-trying-to-make-fetch-happen

Posted by: HSchirmer Dec 31 2017, 08:10 PM

Hey, there may be a new "best actual engineering demonstration" for sails.

The "plasma magnet sail"

It's a magnetic sail that traps the solar wind using current induced in solar plasma instead of current in a solid superconducting ring.

That's roughly analagous to the advance in electric generation which occured when designs switched from "magneto" with a rotating iron bar magnet
to the "dynamo" where the magnetic field is created by current flowing through field coils.

Propbably the most interesting sail proposal I've ever seen -

10. Missions Enabled by Plasma Magnet Sails
Plenary talk by Jeff Greason, Board Chairman, Tau Zero Foundation, Oct. 5, 2017, Huntsville, AL
https://www.youtube.com/watch?v=0vVOtrAnIxM

Combined that with the recent work on Magneto Aeroshell Braking for stopping.
https://www.nasa.gov/feature/magnetoshell-aerocapture-for-manned-missions-and-planetary-deep-space-orbiters You might not need a heavy rentry shield and meters-wide parachute, if you've got a tunable magnetic field...


Combine the two, and suddenly you've got some extremely interesting real entineering "electromagnetic propulsion" possibilites.