[2300AD] Realistic Star Map Project: Part II – Overview

So what could humanity’s expansion to the stars in 2300AD look like with a realistic star map? It could look like this…

The Realistic Arms of 2300AD

The Realistic Arms of 2300AD (click to expand)

The map above shows all of the stars within 60 lightyears of Sol, though only the stars on the French, Chinese, and American Arms are labelled (as well as those of all of the other space-faring nations and alien races). Obviously there’s a lot to digest in there – I’ll be discussing the arms individually in later posts, but in this post I’ll be providing an overview of what’s going on. As I pointed out in my previous post, this is merely my own personal (obviously non-canonical) interpretation of where the Arms would go – I’ve tried to keep as many systems in common with the original arms as I could given the more realistic stellar distribution, but this is by no means the only path the Arms could take.
Continue reading ‘[2300AD] Realistic Star Map Project: Part II – Overview’

[2300AD] Realistic Near Star Map Project: Part I – Introduction

Realistic Near Star Map with new Arms! Scroll down and play the video!

OK, 2300AD fans – you may recall that last year in my 2300AD Near Star Map post I examined how the Arms in 2300AD shaped up when compared to our current knowledge of stellar distribution and discovered that they were actually pretty wrong, with lots of missing stars and broken links.

Also over the past year I’ve been (slowly) tracking down and compiling Star Catalogues on my Stellar Mapping page so I can figure out where the stars around Sol actually are.
Continue reading ‘[2300AD] Realistic Near Star Map Project: Part I – Introduction’

System Book 2: Xibalba is now available!

Lately I’ve been busy writing a new System Book for Spica Publishing, and I am pleased to announce that System Book 2: Xibalba is now available for purchase!

Xibalba originally started off as a one-paragraph writeup for the (now probably dead) Spica Sector book – but we were looking for interesting things to release as smaller products, and we figured it’d be fun to expand upon it and release it as the next System Book. Quite a bit of science went into designing this system to be as realistic as possible (like System Book 1: Katringa before it, which I co-authored), which is named after the asteroid belt that orbits its white dwarf primary. I evolved the star itself and incorporated the effects of the star’s red giant phases on its worlds – one planet was consumed during the giant phase, another’s surface was completely melted, and all of the planetary orbits expanded outwards as the primary lost its mass during its planetary nebula phase (again, Gravity Simulator proved very useful for this!).

The ‘adventure hook’ is that there are strange hauntings and manifestations occurring in the system that have so far defied explanation, and there is plenty for any visting PCs to investigate. I wanted to bring some mystery and a sense of wonder and of the unknown to the setting, but it’s designed to be more “spooky” than “horror”. Inspirations include the movies Solaris, Event Horizon, and the Terran Trade Authority: Spacewreck book. It may be smaller (and cheaper) than System Book 1: Katringa, but there’s still plenty to explore!

Are you brave enough to Visit Xibalba?

Spica Publishing is pleased to announce that its latest product – System Book 2: Xibalba – is now available from RPGnow and DrivethruRPG. This 9-page PDF is written by Constantine Thomas, and is available for $3.99.

Spica Publishing presents System Book 2: Xibalba – a complete planetary system around a white dwarf star. This supplement is compatible with the current edition of the Traveller or any other SF RPG, and can be incorporated into an existing campaign or used as the focal point of an adventure. Inexplicable events plague the inhabitants of the system – are they really haunted by the ghosts of the dead, or is there a more rational explanation for the manifestations?

System Book 2: Xibalba includes:
– A realistic planetary system, based on current astrophysical knowledge.
– Details of the worlds in the system, including the barren worlds of Akabna, Balamna, and Chamna, the Xibalba belt, and the distant gas giant Sisna.
– A description of the small mining community on the asteroid of Nuevo Tikal.
– A brief history of the system and its major events, including the madness that destroyed the Caracol habitat.
– Ideas and suggestions for the strange ‘manifestations’ that haunt the inhabitants of the Xibalba system.
– Adventure seeds to occupy Player Characters while in the Xibalba system.
– Rules for incorporating Xibalba into Spica Publishing’s Outer Veil setting.

Download it today!

“Traveller” and the Traveller logo are Trademarks owned by Far Future Enterprises, Inc. and are used with permission. The Traveller Main Rulebook is available from Mongoose Publishing.

[Science] A natural nuclear reactor on Mars? Not likely…

A nuclear explosion on Mars? Not likely...

A nuclear explosion on Mars? Not likely…

An article by SF writer Charles Stross has been doing the rounds over the past week, describing an LPSC abstract which mentions “evidence” for a possible ancient nuclear explosion on Mars, caused by a “natural nuclear reactor” going critical. A lot of folks seem to be getting a bit excited by this because (not unreasonably) they think that since it’s published it must be scientifically valid, and I feel obliged to put on my party pooper hat and point out that it probably isn’t.

So first things first – here’s the LPSC abstract.

Now, you may be surprised to know that there IS actually such a thing as a “natural nuclear reactor”. We have evidence that at least one existed on Earth – at Oklo in Ghana – and you can read all about it on its wikipedia page. Essentially, you can get circumstances occurring in nature that are similar to those that occur in a nuclear fission reactor, if you have the right combination of geology, radioactive ore bodies and groundwater acting as a moderator. (you’ll note that the Mars “reactor” got a mention on the wikipedia page – that’s likely to be disappearing soon, given the scrutiny the abstract is now receiving).

So, why should we be skeptical of this LPSC abstract?

Peer review

Peer-review is a pretty important part of scientific methodology – it’s the process by which ideas are discussed and scrutinised and criticised and accepted (or rejected) by the scientific community. For a paper to be accepted for publication it must pass the peer-review process, which means that experts in the field have looked at the science, examined the evidence, and possibly duplicated any described experiments themselves and verified that the conclusions reached are valid. If they don’t then the paper is rejected, and the authors must either do more work to demonstrate their hypothesis or just start again and try another approach (or move on to something else). However, the article being discussed here is not a paper, it’s a conference abstract.

Conference Abstracts are not the same as papers. Conference abstracts are normally short summaries of work in progress – especially for teams working on ongoing missions – or interesting hypotheses that could be considered, and they may or may not be developed into papers later on (LPSC, DPS, and AGU are three of the big planetary conferences where abstracts are presented). Some are presented at the conference as posters or talks where they can be discussed further. Some of them get shot down, some pass scrutiny – that’s how science works. I’ve submitted and presented a few LPSC abstracts myself while I was at university – some worked out, some didn’t. The important thing though is that they are not peer-reviewed at all.

At this point I would like to strenuously and enthusiastially point out that the vast majority of abstracts submitted to LPSC are perfectly good science written by scientists and students of science. However, because (as far as I’m aware) the abstracts are not checked or vetted after they’re submitted, a handful of abstracts about… well, I’ll be charitable and call them “less likely scenarios” do slip through. For example, I remember reading one abstract a few years back suggesting that the sun had accreted around a neutron star – which makes no sense in terms of stellar formation/evolution at all. It probably got a few chuckles from those who noticed it, but otherwise it passed by unnoticed at the conference itself because its authors didn’t show up to elaborate on it (granted, a lot of authors aren’t able to turn up to LPSC for many reasons – but if you have a controversial idea then it helps if you show up to defend it!).

So – the important thing to be aware of here is that this is an LPSC abstract that has not been peer-reviewed, which means that its conclusions should be viewed with quite a bit of skepticism.

What about the science though?

There are questions to be raised about the author’s credibility – it doesn’t help that he previously authored an article suggesting that the so-called “Face on Mars” was created by an ancient martian civilisation (even if there ever was any doubt about its origins – not that I think there was – we now have plenty of evidence to show that it’s a completely natural feature). But be that as it may, the proper way to proceed is to analyse the science. Unfortunately, it seems to me that the science in the paper is not very good. Here are a few issues I found:

a) he says that the “reactor” was “tamped” by the overlying rock but doesn’t provide any calculations to support this (and for all I know he forgot that Mars has lower gravity than Earth, so pressure is lower at a given depth). That’s a fairly critical part of the scenario that we just have to take his word for.

b) He also doesn’t provide a satisfactory explanation of how the radioactive ore body forms and how it’s concentrated on Mars in the first place (radioactive ores are not usually concentrated by asteroid impacts).

c) He doesn’t provide any evidence for this supposed explosion beyond “it looks like the radioactive stuff was concentrated around a depression” which could have been caused by a number of other means (e.g. it could have been an depression caused by an ancient asteroid impact). Occam’s Razor seems sorely lacking.

d) I didn’t see a source mentioned for the maps of K and Th distribution presented in the abstract.

e) We know of precisely one natural nuclear reactor on Earth, which implies that they’re somewhat unlikely to form… and it didn’t blow up. And yet there was supposedly one on Mars that did? Seems like a lot of unlikely coincidences would have to line up to make that happen on the next planet over from us.

f) And he spends a lot of time telling us his interpretation of the data, and not a lot of time just objectively describing the data and saying what other options could explain it.

g) if this happened so long ago, why would there be evidence left on the surface after a billion years of deposition and erosion (and redeposition) by the winds that scour the surface of Mars? Surely that would have redistributed the material (if not hidden it)?

And this is before I even get to the nuclear physics side of it… I’ll leave that for others more knowledgeable about the subject. Either way, while some discussion and dissection of the evidence is happening now on various internet fora (now that it’s got some attention), so far the verdict is that the evidence to support the hypothesis is lacking.

So in the end I’d say that the “evidence for a nuclear reactor on Mars” – particularly one that exploded and blasted radioactive material across the planet – seems to be rather unconvincing! It’s an interesting idea to examine and dissect (that’s pretty much why it’s there, after all), but this does show that we need to always critically assess what we see on the internet so that we don’t mistake unreviewed conference abstracts for peer-reviewed science!

Addendum: And funnily enough, this LPSC abstract even gets a mention in this rather excellent video (around the 2:47 mark) explaining how the popular media often doesn’t really understand the science it reports.

[Boardgames] High Frontier – first session report!

HFcover
High Frontier is a realistic “science-adventure boardgame” where you play the role of space agencies who research technologies, launch them on rockets into the solar system to exploit the resources out there, and build extraterrestrial factories that in turn can build new fancier technologies. These give you victory points, and once you’ve built a certain number of factories, the game ends and you count up the VPs. It’s a little intimidating at first, but between a good walkthrough and the High Frontier yahoo group I managed to figure it out enough to give it a shot. The game itself does have a lot of science in it (the map does look a bit terrifying, but it’s actually very realistic in terms of energy requirements), but once you look at the actual gameplay it’s actually not that hard to understand what’s going on.

If you don’t know about the High Frontier board game then its BoardGameGeek page has lots of info. It’s available from most board game stores or directly from Sierra Madre Games – there’s one expansion out already that covers the outer solar system (the rules for the expansion are already in the base game), and there’s a new High Frontier: Colonization expansion coming out soon that extends the map further into the outer Kuiper belt and adds new rules for colonies (you can preorder that from SMG too).

So here’s a little session report that I wrote of our first attempt at playing it over the weekend. We do plan to play again so hopefully I’ll be able to take some pictures of the action next time, and I’ll write up a proper review of the game after a few more playthroughs. Meanwhile, enjoy the action :).

—-

I finally managed to play High Frontier for the first time last night after spending all week poring over the rules… AND IT WAS AWESOME! :).

I played with two gaming buddies – I picked ESA, one picked NASA, and the third picked China. We played using only the basic rules and we started off with just the basic map, but we brought in the expanded map (out to Saturn) later on for more targets. We had a spot of bother straight away because the first thruster that was picked was a 1-0 solar sail and we were trying to figure out how it worked, but we solved that and got going.

NASA was first into LEO and decided to head off to asteroid Phaeton on its solar sail and with an ISRU 4 robonaut just so we could get a rocket going somewhere to see how that all worked. They took a few turns to get there, landed, and (unsurprisingly) failed the prospect roll. Then they decomissioned the rocket, started up a new one at LEO and headed off to the main belt.

China was in the air next with the other robonaut/solar sail combo, headed off to asteroid Khufu and actually managed to prospect there successfully to get a claim! But they didn’t have a refinery with them so they decommissioned and sent up another rocket there with a robonaut/refinery combo so they could set up a factory later.

ESA (that’s me!) took its sweet time building its rocket (everything in ESA is built by committee, you know). However, we were ambitious from the start and went for a full three-stage (robonaut-refinery-thruster) rocket setup for our first launch – we weren’t having any of this namby-pamby hippy solar sail crap! 🙂 We built a MAN’S rocket – a Ponderomotive VASIMR! But that meant we had a rocket that was about twice as heavy as the others to launch (mass 9 vs mass 4 and 5) so we had to spend more time building up fuel. Eventually ESA got into LEO though, to much cheering from mission control :), and decided its mission target was asteroid Minerva in the Gefion family.

Unfortunately by this time the pesky Americans had managed to launch their new rocket from LEO with a better thruster, and had beaten ESA to the asteroid belt, where they started their nefarious goal of blackening the asteroid belt by zapping as many of them as possible from orbit! There was much wailing and gnashing of teeth at ESA as we watched Minerva and the other small rocks of the Gefion family being mercilessly blackened by NASA’s rayguns – particularly as the ESA rocket was already enroute just past the Sun-Earth L2 Lagrange. NASA at least managed to prospect Ceres successfully but only because they couldn’t really fail that!

So Plan B was hastily assembled at ESA mission control, and we decided to try our luck at asteroid Hertha in the Nysa family, where our ISRU 2 raygun would be useful too. [I was going for size 3 worlds because I could land/take off from them without needing lander fuel – I had thrust 3, -1 for wet mass, +1 for beamed power, and I could use the afterburner to get another +1 for a total of 4 thrust. Also, size 3 is a 50:50 chance of actually getting a claim, which is better than 1 in 6 or 1 in 3].

Naturally, the universe continued to mock ESA as we also managed to completely blacken the Nysa family once we got there :(. But at least we could refuel on Hertha, and Plan C was formulated after all the players agreed to use the Expanded Map to find more targets (otherwise I was kinda screwed, since there aren’t any other size 3 hydrated bodies on the basic map). With new vistas of space open to us, ESA decided to head off to asteroid Lutetia to see if we could stake a claim there.

Meanwhile, the Chinese had managed to get their factory set up at Khufu, and managed to develop the Zubrin thruster there (uh-oh…), and promptly decided to use that to conquer the solar system by sending it back to Earth and loading up another robot/refinery package on it to build another factory elsewhere. Since the Zubrin drive basically allows them to go anywhere in one turn (15 thrust – 1/3 fuel/burn), they promptly set up shop on Jupiter’s outermost Galilean satellite Callisto.

While this was happening, NASA had been happily turning the Koronis cluster in the asteroid belt into a blackened wasteland, and had moved on to the Vesta cluster where they finally managed to get claims on Vesta, Unitas and Eichsfeldia. They built a factory on Eichsfeldia, refuelled there, launched again to plunder more asteroids, and promptly turned themselves into a new crater on asteroid Ida [they failed the ‘rapid rotation” crash hazard roll], thus ending their asteroid-killing spree. Fortunately their new factory was nearby so they sent up a freighter with a new instance of their black (robonaut?) card to pick that up with an earthbound rocket later (they didn’t really get a chance to do much after that).

ESA’s mission to Lutetia was also a disaster (the dice really hated me!), but at least we managed to refuel on its now scorched, blackened surface. ESA obviously had the utmost trust in their equipment by having so many backup plans, but at this point we were getting a bit desperate. That said, I guess it was testimony to our spacecraft that it had survived for so long and visited so many targets (there really should be some kind of VP reward for doing that with a single ship…). So, while the Chinese were busy zipping around the solar system and setting up their new base in Asgard’s ice spires on Callisto, we made a last-ditch effort to stake a claim on asteroid Hygiea.

Hygiea’s ‘siblings’ Badenia and Friederike turned out to be a bust, but FINALLY ESA got lucky on Hygiea itself and managed to stake a claim and build a factory there (we landed on fumes!)! Cue much raucous celebration at ESA Mission Control!!

ESA didn’t have much of a plan after that, but we noticed that we could actually get to Ganymede and at least claim that. Armed with our newly-minted Nanobot robonaut (black, ISRU 1, buggy) the refuelled ESA rocket managed to land on Memphis Facula and claim both Ganymede locations (no factory though since I didn’t have a refinery)! [this was particularly cool moment for me, since I’d spent a good chunk of my PhD studying Ganymede, so it was only fair that I claim it! :)]. ESA and China now both had claims in the Galileans and were eyeing eachother warily over the gap – fortunately the Chinese didn’t try to jump ESA’s Ganymede claims though.

Having accomplished ESA’s main mission – and being quite tired by this point since it was now the wee hours of the morning – I wasn’t actually sure what to do next so I ended up turning my rocket into an outpost on Ganymede and attempted to start a new rocket at LEO to find a new target. China had meanwhile turned its greedy eyes on NASA’s Vesta claim, claim jumped it and built a factory on it for good measure. I’d just managed to boost my rocket into orbit and was considering a trip to Mars, but the Chinese managed to get Space Tourism (Space Venture) and then paid the 5 WT to end the game since they had three ET factories (Khufu, Callisto, and Vesta).

So the Chinese won by miles (I think they ended up with 24 VP, and ESA and NASA both had 9 VP), but despite the length of the game and our initial trouble we all agreed that it’d be fun to try it again now that we had some idea what we were doing, so I consider that mission accomplished! 🙂

I think we did everything correctly, but being our first game I’m sure we probably slipped up in a few places (and we’re still not sure what the general strategy should be). But I’ll ask questions on the HF Yahoo Group and hopefully get those sorted out by the next time we play! (and next time, I’ll take photos 😉 ).

[2300AD] Near Star Map Astrosynthesis DB file

This week I received an email request for the Astrosynthesis DB file that I used to make my realistic 2300AD near star/arms map, and after digging it up I figured I may as well post it for everyone to use. It uses a special version of the realistic stellar databases that I’ve presented elsewhere on this site – it has the 2300AD-specific names for the stars and systems, so it shouldn’t be used for scientific purposes (I think it just uses the RECONS + DENSE + Hipparcos databases). As usual, please don’t redistribute this yourself – just link back to this page if you want to spread the word!

Instructions: Click the image below to download the 2300AD_DB.zip file, unzip it into a local folder, open Astrosynthesis 3.0, and open the unzipped 2300AD.AstroDB file from there. Hopefully it’s some use! 🙂

2300AD Astrosynthesis 3.0 database file



Copyright stuff: The 2300 AD game in all forms is owned by Far Future Enterprises. Copyright 1986 – 2012 Far Future Enterprises. 2300 AD is a registered trademark of Far Future Enterprises. Far Future permits web sites and fanzines for this game, provided it contains this notice, that Far Future is notified, and subject to a withdrawal of permission on 90 days notice. The contents of this site are for personal, non-commercial use only. Any use of Far Future Enterprises’s copyrighted material or trademarks anywhere on this web site and its files should not be viewed as a challenge to those copyrights or trademarks. In addition, any program/articles/file on this site cannot be republished or distributed without the consent of the author who contributed it.

Curiosity Sol 2 & 3 Image Roundup!

Curiosity is still doing very well on the surface of Mars, and some full resolution images have arrived back here on Earth over the past couple of days!

First there’s this overview of Curiosity and all its associated landing paraphernalia, taken by Mars Reconnaissance Orbiter’s HIRISE camera in orbit around the red planet – the heatshield, skycrane, parachute and backshell are all accounted for, as is Curiosity itself (labelled as “MSL” – Mars Science Laboratory). The dark patch around Curiosity itself was caused by the backblast if the skycrane’s rocket motors as it was being lowered to the ground – brighter dust was blown away, leaving darker material behind. To get a sense of scale, the skycrane is located at a distance of 650 metres from Curiosity. There are no plans to go and visit any of the wreckage, however.

Curiosity landing site (image credits: NASA/JPL/MSSS)

Curiosity’s Cameras

Before I go on, I should explain the cameras that Curiosity uses to take pictures – there are 17 of them in total, so it can be difficult to keep track of them all! The sensor mast (Curiosity’s Wall-E like “head”) containing the cameras was successfully raised on Sol 2 and seems to be working fine.

The cameras on Curiosity’s sensor mast
(image credits: NASA/JPL/Constantine Thomas (labels))

The CHEMCAM (not used yet) is the round opening at the top. This shoots a laser at distant rocks (!) – CHEMCAM’s spectrometers and telescope can then determine the composition of the rock by analysing the puff of material blown off by the laser (which is pretty darn clever, really).

The NAVCAMs are the two little cylindrical things on the left and right of the “head”, below the CHEMCAM. There are two on each side, but only one left/right pair is used at a time – the other is a backup. This allows Curiosity to take stereo images, which can be used to make 3D anaglyph images.

The MASTCAMs are the two trumpet-like things mounted below the CHEMCAM. The one with the wider opening directly below CHEMCAM is the wide angle camera, and the one on its right is the telephoto camera. These won’t be able to take stereo images because they aren’t the same kind of camera, but they’ll be taking the bulk of the high resolution images of the landscape.

There are also the front and rear HAZCAMs (there are actually eight of these, mounted on all four corners of the rover), which take low resolution images of what’s immediately in front of and behind the rover in order to avoid obstacles – we’ve already seen pictures from those that were taken shortly after Curiosity landed. MARDI is the MARs Descent Imager, which is on the bottom of Curiosity and was used to take the Descent video. Last I heard on one of the press conferences, the team were hoping to get some further use out of this camera by taking pictures of the ground directly under the rover, since some light can still get through underneath the rover. And then there’s MAHLI (MArs Hand Lens Imager), which is the hand-lens imager mounted on a robotic arm that will be used to take closeup shots of the rocks that Curiosity examines (and can also apparently be used to image more distant objects too).

If you want a more complete roundup of what these instruments (and others) do, wikipedia explains all!

OK. Now you know what’s taking all the pictures, let’s go back to the images!

Next up is the first view from the NAVCAMs. While these can be used to take 3D stereo images if they are taken in pairs (you’ll need red-blue glasses to view them – apparently comic shops may be a good place to find these!), they can of course also be viewed as individual images too – this is the first high resolution scene returned from Curiosity through the left NAVCAM, and the scenery looks pretty astounding. I love the hazy mountains of the crater rim in the distance, and the detail in all the rocks and pebbles in the foreground!:

The view from Curiosity (left NAVCAM) – Image credits: NASA/JPL-Caltech

The NAVCAMs managed to get a good look around the whole rover, and the images were stitched together to make this amazing 360° view of the rover’s surroundings. Mount Sharp (the central peak of Gale crater) is at the bottom/left of the image (the rover’s pointing in its general direction), the crater rim is visible to the right, and I think the sun’s washing out the horizon at the top of the image. I love how you can actually see the rover here (I would have expected some distortion because of the 360° view, but it looks nicely rover-shaped!) – also note the bits of gravel on the top surface of Curiosity, which were kicked up by the skycrane’s rockets as it was landing!

360 degree view around Curiosity – Image credits: NASA/JPL-Caltech/James Sorenson

Finally, the MASTCAM was fired up and returned this very nice colour panorama looking towards Mount Sharp. The dark streaks at the base of the mountain are sand dunes – from what I gathered from the press conferences, Curiosity is going to be heading towards them (skirting the left side in this view) once it starts moving in a couple of weeks. There are several very cool things to note here – first, this panorama is actually made up of 130 thumbnail images with a resolution of 144×144 pixels – these aren’t even full resolution images (which are 1200×1200 pixels), so the full resolution panorama will be absolutely enormous and ridiculously detailed! We’ll have to wait a few days for that to come back down though, since updating the rover’s software is a higher priority in the coming days. Second, the grey circular patches on the left and right are where the skycrane’s rockets blew away some of the dust during the landing, which means that bedrock might be exposed there! Third, that line of holes in the treads of the wheels apparently spell out “JPL” in morse code… so Curiosity will be leaving JPL’s name in its tracks in the martian dust as it travels!

Curiosity MASTCAM colour panorama (Image Credits: NASA/JPL-Caltech/MSSS)

As always, if you want more info, check out Emily Lakdawalla’s Planetary Society blog!

More images from Curiosity!

There was another press conference at 4pm PDT this afternoon where the MSL team showed off some more awesome images!

This one is from the front HAZCAM, and by good fortune it looks like Curiosity is pointing towards Mt. Sharp, the mountain at the centre of Gale crater that it’s going to be climbing throughout the mission! The dark line in the foreground is actually a field of sand dunes between the rover and the mountain!

Front HAZCAM view, showing Curiosity’s shadow, and Mount Sharp looming in the distance. (Image credits: JPL/NASA/UA)

Another VERY cool thing they released was a low resolution video showing the descent of Curiosity, taken from the MARDI camera (MARs Dscent Imager) – they took 220 frames and stitched them together to make the video. They’ll be sending back higher resolution images over the next few weeks, so this is going to look even more spectacular soon. But meanwhile, feast your eyes on this:

MARDI video of Curiosity’s descent (that’s the heat shield dropping away in the first few frames!) (image credits: NASA/JPL/MSSS)

Again, Emily Lakdawalla has more details so I’ll point you to her article for those rather than repeat it all here :).

Curiosity is on Mars!

Curiosity (more formally known as the Mars Science Laboratory) has landed successfully on Mars! A very complex landing system (The so-called Seven Minutes of Terror) was required to get such a massive (one ton!) rover safely on the ground, but it seems to have worked flawlessly – it landed with a vertical velocity of 0.75 metres per second, and a horizontal velocity of only 4 centimetres per second, and well within its estimated landing ellipse – well done to everyone involved!

Curiosity’s shadow on the surface of Mars! (Image credits: NASA/JPL/UA)

There’s a news conference at 9am PDT today, apparently they’ll be showing images from Mars Reconnaissance Orbiter’s HiRISE camera of Curiosity on its way in to landing on Mars! There’ll be another at 4pm PDT possibly with MARDI (Mars Descenmt Imager) images too – You’ll be able to watch a livestream of the news conference (and future ones) here: http://www.nasa.gov/externalflash/mars/curiosity_news3.html.

Meanwhile, here’s a very nice summary of what we have so far from Emily Lakdawalla at the Planetary Society.

And if you want to see the scenes at mission control during the “Seven Minutes of Terror” as Curiosity landed, you can watch them here – it’s pretty tense!

This is going to be an awesome mission. Curiosity has enough power for 2 years of roving, but it’s undoubtedly going to last longer than that (the only real limitation is the life of the mechanisms and motors, but they’ve apparently been tested to at least three times the mission duration). Stay tuned for some amazing images over the coming weeks, months and years!

EDIT: And here’s the MRO picture! The orbiter was almost directly overhead, about 340 km away – even from this distance you can see a lot of detail on the parachute and the backplate (you can read more about it from Emily here).

Curiosity parachuting in, viewed from the HiRISE camera! (Image courtesy: NASA/JPL/UA)

They’ll be spending Sol 1 (a Sol is a day on Mars) checking out the equipment and should be getting the High Gain Antenna up and running later this afternoon – that’ll allow the rover to communicate directly with Earth. Over the next few Sols they’ll be raising the Mastcams, taking some higher resolution pictures, and getting the onboard equipment up and running, and then hopefully in a couple of weeks once they’ve made sure everything is working properly they’ll take Curiosity on her first drive. There’s no rush though 🙂

[Stellar Mapping] Brown Dwarf dataset added, plus some major updates!

I’ve added a new Brown Dwarf dataset to the Stellar Mapping page (thanks to LiNeNoiSe for pointing this out to me)! This should hopefully be the last major update to the stellar datasets for a while – the next project on the list is to figure out what the reworked Arms for 2300AD might look like based on the realistic data.

The new catalogue is the LDwarf dataset – this is a list of brown dwarfs taken from the IPAC Brown Dwarf Archives (this dataset was last updated on 14 Feb 2011). It is not a complete list of all known brown dwarfs – these are the only the ones for which parallax data is provided there.

L Dwarf dataset, looking Corewards

While some of the distances presented in this dataset are derived from trigonometric parallaxes, others are derived instead from (spectro)photometric parallaxes. Trigonometric parallaxes are derived by measuring the angular shift of a star relative to the background stars as the earth moves around the sun on its orbit (the stellar distances in the HIPX, RECONS and other datasets here are derived using this method) – these are generally more accurate than photometric parallaxes. “Photometric parallaxes” are techically not really “parallaxes” at all – instead the spectral type of the object is checked against luminosity models to get an estimate of its luminosity, which is used along with the observed visual/IR magnitude to calculate the distance to the object. Unfortunately this method is not very precise, and some of the photometric parallaxes for these objects in the LDwarf dataset have very large error bars – but this is the best data that is currently available.

One of these systems – SDSS J141-134 – is listed in the original data as having a (photometric) parallax of 127 +/- 27 mas. This places it almost in the right location to allow a 7.7 ly link between Xi Bootis and CE Bootis, which would be very useful in the 2300AD setting. I have changed its parallax to 122 mas on this list (which is comfortably within its error bars, and allows it to connect those two stars and link to the stars around Arcturus). The original (127 mas) data for this system is listed in the text file in the LDwarf.zip file if it’s needed.

It should also be noted that two Brown Dwarfs (UGPS J072227.51-054031.2 and DENIS J081730.0-615520) are located within the RECONS sphere. These are not listed in the RECONS data, but are retained here since their parallaxes indicate that they are within 22.8 lightyears of Sol (even given their large error bars). They do not make a significant difference to the 2300AD route distribution.

Some of the Brown Dwarfs in this list are members of multiple systems that are listed in other datasets presented on this site. These are listed as complete multiple star systems on this list (the other components are duplicated here using the original data) – the datasets should merge seamlessly when combined (the ID numbers are preserved in both lists) but some components may be duplicated – this should not create problems since they will have the same name and position.

Other Updates

I’ve also made several other updates to the datasets, so you’ll need to download them again to get the latest versions!

  • The Pleiades Corridor has been updated to use Extended Hipparcos data.
  • The Yale and Gliese 3 Historical Datasets have been moved into a blog article to separate them from the more accurate datasets on the Stellar Mapping page.
  • The Extended Hipparcos and CTIOPI datasets have been updated to include Multiple Systems. A and B components of some of the multiple stars in the original data were separated by several lightyears due to parallax inconsistencies – these were listed separately, but now they have been combined nto Multiple star systems that are located at the XYZ co-ordinates of the original A component.
  • The Further Stars list is still using New Reduction Hipparcos (and other) data. I will be updating it to HIPX at a later date, but it does contain duplicate stars in different positions and should be considered to be less accurate than the other datasets!