May 4th, 2013
It looks as if when NASA's New Horizons probe arrives at Pluto in 2015 it's going to find weather that is both relatively simple and yet quite difficult to predict:
To establish context: Pluto, like Earth and Titan, has a nitrogen-rich atmosphere. It's a very thin atmosphere, its pressure measured in microbars. Earth's atmospheric pressure is, of course, about one bar. Titan's is 1.6 bars. Mars' is a hundred times more tenuous, less than 10 millibars. Pluto's is about a hundred times more tenuous again, less than 100 microbars. Which is really thin; but it's way thicker than the essentially airless exospheres at Mercury and the Moon. Pluto has plenty enough atmosphere for the world to have wind and weather and clouds, just like Venus and Earth and Mars and Titan.
Nitrogen in Pluto's air is in equilibrium with nitrogen frost or ice on the ground. Broadly speaking, when Pluto warms up, ice sublimates to gas, and the atmospheric pressure goes up. When Pluto cools, you get frost and a lower atmospheric pressure. Changing seasons remove ice from the summer pole, and may re-deposit it at the winter pole.
Emily Lakdawalla's post goes into much more detail about why it's so hard to predict what New Horizons will find, even taking into account what we know from probes to destinations elsewhere in the solar system. Which, as she notes, is exactly why it's necessary to send a spaceship out to Pluto – to tell us which theories are right and which are wrong (and in turn to fuel a couple of decades-worth of scientific papers figuring out whether the theories that gave the right answers did so for the right reasons.)
In the meantime, New Horizons will be heading on out to the Kuiper Belt, which promises to be interesting in an entirely different way.
April 3rd, 2013
Twenty Awesome Covers From The US Space Program. My favourite is the cover for the manual for the NASA/Grumman Apollo Lunar Module: nothing else looks like the LM.
[Via Extenuating Circumstances]
March 25th, 2013
Posting at The Planetary Society, Bill Dunford found A Different Angle on Mars by looking back at images from the Mars Global Surveyor:
Like all Mars Global Surveyor shots, these are views of the Red Planet from orbit. What's different here is the highly oblique angle of these images. In each, the powerful Mars Observer Camera is not oriented straight down for maximum resolution, but off toward the horizon.
The result is a set of views that make me think of what it might be like to be at Mars, flying over the planet in person, looking out the window. Be sure to enlarge them, and see if you enjoy them as much as I did.
I reckon the image of Olympus Mons is my favourite, just because it emphasises the sheer scale of the thing.
I know the various space agencies have to choose the sites where they land their probes so as to maximise both the chances of a successful landing and the amount of useful science they can do in their limited lifespan, but it'd be nice if at some point in the future someone could contrive to bring down a lander somewhere near the peak of Olympus Mons. The view from up there across the planet's surface would be a sight to see.
September 5th, 2012
I wonder how many science fiction writers have drafted stories where this phenomenon is a deeply meaningful, possibly even elegiac, symbol of … something or other…
While the $5.50 nylon flags are still waving on the windless orb, they are not flags of the United States of America anymore. All Moon and material experts have no doubt about it: the flags are now completely white. If you leave a flag on Earth for 43 years, it would be almost completely faded. On the Moon, with no atmospheric protection whatsoever, that process happens a lot faster. The stars and stripes disappeared from our Moon flags quite some time ago.
Alternatively, this is just another attempt by NASA to drum up support for another series of moonshots:
Mr President, we can't let the next passing alien invasion fleet think we've surrendered. We must go back and plant a pristine flag at Tranquility, oh, every decade or so.
August 6th, 2012
It turns out that as Curiosity was coming in for a landing this morning, NASA's Mars Reconnaissance Orbiter was watching.
[Via Nicholas, commenting at this Making Light thread]
June 23rd, 2012
Jupiter's Rings Revealed.
Also worth noting: Astronomy Picture of the Day has now been publishing for 17 years. I'm a little surprised it's only been 17 years; I felt sure that APOD had been there ever since I first encountered the World Wide Web.
June 22nd, 2012
I've seen CGI simulations of Curiosity's Seven Minutes of Terror before, but it does no harm to be reminded of just how insane a ride the Curiosity rover is going to have on the 5th of August when it lands on Mars.
I know there's no way NASA could afford to do it, but it's a shame that they couldn't have landed a smaller, simpler lander in the vicinity of the landing site just before Curiosity is due to descend from orbit. A lander with just one job: providing us with real-time moving pictures of Curiosity coming in to land. Fail or succeed, it's going to be quite some spectacle, and it's a damned shame that we're never going to get to get a proper look at what happened.
May 13th, 2012
The flight of a Space Shuttle as seen from a Solid Rocket Booster. I've posted links to this sort of film before, but in this film instead of providing a musical accompaniment to the SRB's descent, Skywalker Sound enhanced the sound from the SRB-mounted cameras; stark, bright images and the sound of a rocket tumbling from the upper atmosphere combine to mesmerising effect.
[Via More Words, Deeper Hole]
April 8th, 2012
Fifty years on from NASA's Project Gemini, the Atlantic has a fantastic collection of photographs taken during the project's four year run.
What strikes me is how small the Gemini capsule was; more or less the size of a small car. When they wanted to try a spacewalk, the astronauts would just suit up, then wind down a window to get direct access to space.
December 7th, 2011
Emily Lakdawalla reports from the 2011 Fall Meeting of the American Geophysical Union:
Voyager 1 is very close to the heliopause. Last year at this time, the Voyager team reported that the outward-directed speed of the solar wind had dropped nearly to zero. With this observation and a mental model of the way the boundary between the solar wind and the interstellar medium should work, they formed a hypothesis: we are near the heliopause, and the direction of the energetic particles that Voyager 1 can measure should be shifting from the outward and east-west directed flow to a north-south one, the direction of the interstellar medium. So the simple experiment that the scientists needed to do to test their hypothesis was to measure the north-south flow of energetic particles. They predicted that they should be seeing increased north-south flow, matching the interstellar medium.
There are three cool aspects to what happened next.
- In order to perform the experiment the scientists would have to get Voyager 1 to change orientation – something it last managed 21 years ago. Not only did Voyager 1 pull this off, but it did so four times so that they could check their findings.
- The scientists found that their eminently plausible hypothesis was completely unsupported by the evidence Voyager produced. Cue much scratching of heads, and the formulation of a new hypothesis.
- With any luck, Voyager still will be around to test that hypothesis in due course.
Given that Voyager 1 was launched in 1977 and is still producing worthwhile scientific data thirty-plus years on, it must be the most cost-effective satellite in the history of space exploration.
October 9th, 2011
After their splashdown in the Pacific, the Apollo 11 astronauts had to fill in their customs paperwork upon their arrival at Honolulu airport, just like every other inbound traveller.
I can't help but notice that the one section of this paperwork that might have been considered of some practical importance – i.e. the part asking about the possibility of spreading disease – had to be answered TO BE DETERMINED, what with the astronauts still being in quarantine at that point.
[Via The Brooks Review]
September 11th, 2011
My favourite thing about the Lunar Reconnaissance Orbiter's images of the Apollo lunar landing sites is that you can still see the tracks of the lunar rovers, and the trails left by the astronauts walking from the lander to the local landmarks.
It's one thing to be aware that there's no atmosphere to disturb the tracks left in the lunar dust, but seeing the evidence almost forty years on is something else entirely.
June 3rd, 2011
Chris Abbas has stitched together a vast number of still images from NASA's Cassini probe to produce Cassini Mission, a stylish, impressionistic piece that looks nothing at all like your typical NASA video. (And I mean that in a good way.)
June 1st, 2011
Two images from the final flight of Space Shuttle Endeavour: shortly after lift-off, and docked with the ISS.
That second image gives a marvellous sense of just how quickly the ISS and the Shuttle are moving. I know it's the long exposure that causes the cities below to turn into a streak of light, but even so they're moving at a fair old clip up there.
[Image of Endeavour docked with the ISS via Bad Astronomy]
May 28th, 2011
January 19th, 2011
With Voyager 1 crossing the (somewhat fuzzy) border between the solar system and interstellar space over the next few years, here's another way to grasp the scale of the mission. Not by the immense number of miles Voyager has travelled, nor by the number of megabytes of data it has sent back to Earth, but by the age of the scientists who worked on the project as young men:
[Voyagers 1 and 2...], now 33 years into their mission, continue to explore new territory as far as 11 billion miles from Earth. And they still make global news. Scientists announced last month that Voyager 1 had outrun the solar wind, the first manmade object to reach the doorstep to interstellar space.
It's amazing even to Stamatios "Tom" Krimigis, of the Johns Hopkins University's Applied Physics Lab near Laurel. He's one of just two principal investigators of the mission's original 11 still on the job 40 years after Voyager was approved by NASA.
"Needless to say, none of us expected it was going to be operating for so long," said Krimigis, now 72. "We were all praying to get to Neptune [in 1989]. But after that? Who thought we could be with this 33 years [after launch]?"
Here's hoping that Krimigis and his colleagues (and the Voyager probes themselves) are still active for years to come.
[Via Ghost in the Machine]
August 28th, 2010
NASA have invited the public to choose a wakeup song for the final Space Shuttle flight. So far, it looks to be a two-horse race:
||% of total
|Star Trek Theme Song
|Magic Carpet Ride
||Big Head Todd
I'm a little surprised that the Star Wars theme has garnered just 0.9% of the vote. I have to assume that once their online fandom gears up they'll crush the likes of Steppenwolf and Rush. Whether the rebel scum can defeat the fandom that managed to get the prototype Space Shuttle named after their favourite starship is another question.
(For the record, my vote went to ELO's Mr Blue Sky, but with just 0.2% of the vote it's got an awful lot of ground to make up.)
[Via The Awl]
July 29th, 2010
During the early years of manned spaceflight, NASA found it impossible to arrange life insurance for the astronauts. The solution to this problem was both ingenious and impeccably market-oriented:
The answer was provided by NASA in the form of 'Insurance Covers', [...] a number of which were given to every crew member and subsequently signed by every astronaut involved, as close to launch as possible. Its value would instantly be high, but would no doubt sky-rocket (no pun intended) should the astronauts never return; the deceased's surviving family then at least safe in the knowledge that in future they could cash-in their makeshift insurance policy if required.
By the time of the Columbia disaster in 2003, NASA had come up with a different approach:
The Americans who died aboard the space shuttle Columbia were eligible for the standard life insurance offered to military personnel and federal employees, but NASA carried no special coverage specifically for astronauts, officials say.
The 12 children of the Columbia astronauts will also be able to receive assistance from the Space Shuttle Children's Trust Fund. The private, nonprofit fund raised about $1.2 million after the 1986 Challenger explosion to provide for the needs of the astronauts' children.
[Via The Null Device]
February 14th, 2010
The Space Shuttle in silhouette.
[Via Bad Astronomy]