Deep Space and Interplanetary Exploration - The Universe is Timeless

[ANS Kamas P81]

Looks like SpaceX has another launch tomorrow, the Jason-3 satellite for climate research - followed by another barge landing attempt.  Good luck guys!

Still, an interesting side effect of that is that very large solar panels suddenly gets much more attractive. If you can make fine adjustments without using any fuel - even if the saved amount is very small - it can pay for quite a bit of extra panels.

Yeah, but flying your satellites around the solar wind like that is pretty tacky.

[Sabelkatten]

Yeah, but flying your satellites around the solar wind like that is pretty tacky.

Boooh!!!

[Maingunnery]

From a local aspect here a very bad development. Our only real space company here in my area builds up to a hundred reaction wheel sets per year in a local factory. As in they kinda have a commercial monopoly on that, globally.  ;D

Kinda like BT, only one supplier of an item on a planet.  ;)

[kato]

Looks like SpaceX has another launch tomorrow, the Jason-3 satellite for climate research - followed by another barge landing attempt.

January 27th will be interesting. Two launches within only 15 minutes planned. ILS with a Proton out of Baikonur and Arianespace with a A5ECA from Kourou.

The barge landing attempt will probably be SpX's last btw. The one flying is the last F9v1.1(R) model that they have. All other rockets in stock are F9FT aka F9v1.2(R).

[ANS Kamas P81]

January 27th will be interesting. Two launches within only 15 minutes planned. ILS with a Proton out of Baikonur and Arianespace with a A5ECA from Kourou.

Neat. If the ISS is lucky they'd have an orbit that lets them see both; it's just about the right timeframe.

[Natasha Kerensky]

The barge landing attempt will probably be SpX's last btw. The one flying is the last F9v1.1(R) model that they have. All other rockets in stock are F9FT aka F9v1.2(R).

Barge landings were developed for when payload mass and/or target orbit require too much propellant burn, leaving too little for the rocket-back maneuver to land.  That can and will still happen with the newer F9.

The three-stick heavy will also almost certainly require a barge landing for reuse.

[kato]

Juno overtook Rosetta as the farthest-out-operating solar-powered spacecraft this week, at about 5.3 AU from the sun. Rosetta's record stood since October 2012. Juno has about 15% larger panels than Rosetta and will operate at a maximum distance of 5.56 AU from the Sun.

In case anyone wonders about the other way, the closest a probe came to the Sun was Helios II in 1976 at 0.29 AU. Helios II, due to its solar gravity assist, also still holds the speed record at 70 km/s for any spacecraft built so far. New Horizons was the next-fastest at 45 km/s heliocentric-relative, most outer-planet probes do around 35-40 km/s. Future plans are for Solar Probe Plus - to launch in 2018 - to reach 0.04 AU and 200 km/s by 2024. Both Helios and Solar Probe Plus employ(ed) solar cells that are angled to lower intake, interestingly.

[kato]

No double launch, ILS has delayed to 29th.

[Sabelkatten]

Both Helios and Solar Probe Plus employ(ed) solar cells that are angled to lower intake, interestingly.

If I understand you correctly (angled to reduce incoming radiation when operating near the sun) it's not that strange. Panels age, and strong radiation makes them age faster. So it makes sense that you'd angle them to catch only as much power as you need and no more.

[kato]

Nah, in this case it's because the close proximity to the sun heats the panels to temperatures which will destroy them pretty rapidly. Messenger's arrays have been the ones designed to the maximum survival temperature so far, and that's only for 550 K; maximum design operating temperature for these arrays was 425 K. For Helios, its simpler array was laid out for a maximum operating temperature of 450 K.

The 550 K value is the glassing temperature of the used special composite substrate material on Messenger's arrays, i.e. the point at which the solar cells will essentially turn to a rubber-like state. Which is definitely not something you want. In addition, high temperature rapidly lowers efficiency for solar cells.

The thermal protection shield on SPP is estimated to reach around 1700 K at perihelion - which is beyond any high-temperature materials available, even fused quartz has a glassing temperature of under 1500 K (Helios though had a similar problem back in the early 70s - they first had to find a binder material to glue the solar cells to the spacecraft that would survive at 400 K). SPP actually has movable wings that fold backwards to a 68-degree angle when the probe is on the inwards leg of its orbits, in order to stay fully shadowed by the thermal protection shield; only the tip of the array reaches into the only partially shadowed penumbra of the craft. When the probe is at aphelion, the solar array wings unfold to still provide power. The shadowing itself is still not enough of a heat prevention measure, so the arrays are additionally water-cooled.

Helios mounted the solar cells on a surface angled away from the flight direction (i.e. the sun) and was additionally spinning at 60 rpm to maximize lit/shadowed sequence in order to not overheat parts of its surface.

Messenger had the solar cells within the arrays conducting into individual heatsinks, effectively. Additionally the panels could be tilted so Messenger could point them edge-wards to the sun to minimize directly exposed surface. ESA has a mission planned for the 2020s (Solar Orbiter) that will go down to 0.20-0.25 AU (i.e. 50-125% more influx than at Mercury) which will use a similar technique - plus panels with a design operating temperature of 500 K.

[Sharpnel]

An interesting read Planet Nine

[worktroll]

Call it "Tor Johnson", then.

Maybe Persephone - spends a few short moments in the (comparative) warmth, then back into the icy hells ...

[Lazarus Jaguar]

Oh come on, we all know the ninth planet is Yuggoth :p

[Daryk]

And here I was figuring they wouldn't be able to resist calling it "Planet X".  I'm sure the "Pluto is a planet!" crowd (at least) will insist.

[ANS Kamas P81]

Wonder if they'll call it Nemesis.

[Wrangler]

I wonder how they'll be able to confirm the planet exists at all.

If it does, it must be on the fringe of the Sun's heliosphere.  Oort cloud must get pushed around by it's gravity.

It be fortunate that one our deep space probes had sensors to that could detect something. I know the older ones like Voyager series and ancient Pioneer series don't have anything like that or the power to do it.

[worktroll]

I wonder how they'll be able to confirm the planet exists at all.

If it does, it must be on the fringe of the Sun's heliosphere.  Oort cloud must get pushed around by it's gravity.

It be fortunate that one our deep space probes had sensors to that could detect something. I know the older ones like Voyager series and ancient Pioneer series don't have anything like that or the power to do it.

The deep space probes are "short sighted", and not in positions to see it. We'd have little way of reprogramming them at this point in time.

Fortunately, though, an ice-giant sized body should be easily resolved by current far-infrared Earth-based telescopes. The team predicting the body's presence are using one such, the Japanese Subaru wide-angle IR telescope, and are cooperating with other teams. They think it'll take about 5 years to map the section of sky Plan(et) Nine is supposed to be in.

W.

[ANS Kamas P81]

Part of the reason noone ever noticed it before is because it's a good 30 degrees off the ecliptic.  Tyche, for lack of a more appropriate name (see Tyche Hypothesis, it's close enough for now), isn't in the typical places we've been searching.  There's clearly a presence of an object, BUT it's not like the case of seeing 17 stars in tight orbit around a black hole.  The objects in question are in a clear arc, but not immediately under strong gravitational effect.

It's akin to looking at a parking lot with some cones on it, seeing a few of them sideways and flattened - you can tell that a car knocked them, and can tell what direction and how fast the car was going and where it was, but it's a big parking lot - and that won't tell you where the car is at the moment.

Fortunately for the sky survey guys, searching outside the ecliptic will be a lot easier.  you won't get a lot of false-positives from unspotted Oort objects; whatever's moving out there is going to pretty much be by itself against the background stars.  At ten times earth's mass, even a rocky body will be over twice the size of earth itself (say, 16-17,000 miles across) and have a very easy to spot signature.  If it's a small gas giant, then it'll be a lot bigger than that, and might just be a fascinating 'ice cream scoop' of the Oort cloud itself.  Either way, an IR search should find it soon enough...

...but I'll bet you every planetary astronomer is gonna blow their spare time hunting this one.  Talk about the chance to stand among giants with spotting the first new planet since 1930.

[Wrangler]

Well, i have to say from all the materials i've read.  It be amazing if it were small gas planet, but i have strong doubts it is.  Won't there be some kind of gravity influence system would show if this thing was swing ever so slowly though?   

I more thinking this is not so big planet like Pluto verse a bigger world they suspect it is.  It will be exciting if they find it.

[ANS Kamas P81]

Gravitational pull says its' got to be at least ten times Dirt's mass, and they've got enough data to determine a 4:9 orbital resonance with some Oort objects that cross its path.  That sounds to me like they have it pretty nailed down, and a tiny object like Pluto is far too small to have the effect they're seeing - Pluto's 1/5000th the mass of whatever's dragging the comets around.

Here's the Caltech report on the paper, and an interview with the details I mentioned.
http://www.caltech.edu/news/caltech-researchers-find-evidence-real-ninth-planet-49523

Interesting side note: 20 times further from the sun than Neptune (30.1 AU) means Tyche is a whopping 600+ AU distant from the sun.  Way, way out into what we used to call interstellar space.  By comparison, Voyager 1 is only 133.85 AU (at the moment I type this) and not even a fourth of the way there.  If we built a probe to go find this thing, even once we had a solid position and movement on it and could aim it, it'd be a probe that our grandkids would have to remember to listen for.

[Weirdo]

So....what's the light-speed delay to something out that far? A light-week or so?

[ANS Kamas P81]

So....what's the light-speed delay to something out that far? A light-week or so?

around 83 hours at 600AU.

[Weirdo]

So it's unimaginably, mind-bogglingly far away...and the star that is so close as to be considered the apartment across the hall, is over 400 times farther than that.


It's a great, big universe, and we're all really puny...

[rebs]

We need to jumpstart the next scientific revolution that leads to alien world-hopping tech.

Also, just thinking about the simplicity of the dynamic here: Plan't Nine dislodges the comets, and Jupiter gobbles up roughly 95% of them. 

Cosmic knife juggling.  Bystanders beware.

I'm comfortable with this.

[BirdofPrey]

Don't forget the bandwidth limitations.  New Horizons isn't anywhere close to as far as a probe to a planet on the oort cloud would be, and the downlink speed is super low due to the low signal strength.  A probe to said planet would have to have a larger antenna array and more powerful transmitter to even be worthwhile, and that's payload not available for instruments.  Such a probe might benefit from being rather large hefted up on a heavy lift launch vehicle.

[ANS Kamas P81]

We managed to hit Pluto with New Horizons fairly close to perihelion.  Distance at that encounter was around 33 AU; now tack on the inverse square law for the 600 AU trip to Planet TenNine (damn Lectroids) and you'd have radio signal strengths roughly equivalent to a mosquito fart in a tornado.

Clearly the answer is manned starships.  BATTLESTAR OR BUST!

[BirdofPrey]

Maybe once we invent warp drive.
In the mean time, gotta put Arecibo into orbit.

[ANS Kamas P81]

Maybe once we invent warp drive.
In the mean time, gotta put Arecibo into orbit.

"Attention Jupiter Station, this is Radio Telescope One.  We Arecibing you."

[Sabelkatten]

We managed to hit Pluto with New Horizons fairly close to perihelion.  Distance at that encounter was around 33 AU; now tack on the inverse square law for the 600 AU trip to Planet TenNine (damn Lectroids) and you'd have radio signal strengths roughly equivalent to a mosquito fart in a tornado.

Clearly the answer is manned starships.  BATTLESTAR OR BUST!

A manned ship would certainly be cool, but maybe not the practical... ;)

I guess such a probe would need a real nuke plant, ion/plasma drive and serious fuel tanks. Really begs for space-based infrastructure to at least get the fuel from upstairs! Wild guess: Around 20 tons for a plant and drive, 5 tons or so for sensors, control and comm, maybe 100 tons of fuel? IIRC that should be able to get you some 50-100 kps delta-v (with probably another couple of dozen from slingshots).

Time for a kickstarter? :D

[ANS Kamas P81]

I can't imagine that still taking less than 30 years to get there; it's just so far out.  But it's nice to know there's an offshore island before you get into the true deep.