Day late and a dollar short

Last week the ESA's Rosetta mission successfully landed the Philae probe onto the surface of Comet 67P/Churyumov–Gerasimenko. Philae bounced several times before finally landing on the side of a cliff. A gentle reminder that for more critical missions which require landing, there is real virtue in having an actual human pilot at the controls.

The total number of bodies in the solar system we have successfully landed anything on intact now stands at seven; the Moon, Venus, Mars, Titan, the asteroids Eros and Itokawa, and comet Chury-Gery. We have returned samples only from the Moon, and asteroid Itokawa.

The next big robotic exploration destination will be when the Dawn spacecraft reaches Ceres next spring. I'm inclined to think that the Dawn Ceres data will be a game-changer in how we prioritize our upcoming human space exploration missions. As such, we'll be following it closely, here.

Snowballing

This Sunday the Oort Cloud comet Siding Spring (also called Comet C/2013 A1) will pass within 140,000 kilometers of Mars. This is about half the distance from the earth to the moon, and much, much closer than any known comet fly-by of earth. It will be observed by rovers on Mars and spacecraft in Mars orbit, as well as terrestrial land-based and space-baced telescopes. Currently orbiting Mars are the Mars Reconnaissance Orbiter (MRO), MAVEN, Mars Odyssey, the ESA Mars Express, and India's Mars Orbiter Mission (MOM). It is only by blind, dumb luck that this one-in-a-million flyby is happening at a time when we are actively surveying Mars for eventual human colonization. This should be a very interesting week.

Race to the Rocks

Now there are two companies competing to mine the asteroids. The race is on!

Ice Hockey

The European Space Agency is planning a mission to try to actually deflect an asteroid from its trajectory. This could be really important to us if we ever found a large asteroid to be on a collision course with earth. Good on them.

Asteroid deflection mission seeks smashing ideas

15 January 2013

A space rock several hundred metres across is heading towards our planet and the last-ditch attempt to avert a disaster – an untested mission to deflect it – fails. This fictional scene of films and novels could well be a reality one day. But what can space agencies do to ensure it works?

ESA is appealing for research ideas to help guide the development of a US–European asteroid deflection mission now under study.

Concepts are being sought for both ground- and space-based investigations, seeking improved understanding of the physics of very high-speed collisions involving both man-made and natural objects in space.

ESA’s call will help to guide future studies linked to the Asteroid Impact and Deflection mission – AIDA.

This innovative but low-budget transatlantic partnership involves the joint operations of two small spacecraft sent to intercept a binary asteroid.

The first Double Asteroid Redirection Test (DART) spacecraft, designed by the US Johns Hopkins Applied Physics Laboratory will collide with the smaller of the two asteroids.

Meanwhile, ESA’s Asteroid Impact Monitor (AIM) craft will survey these bodies in detail, before and after the collision.

The impact should change the pace at which the objects spin around each other, observable from Earth. But AIM’s close-up view will ‘ground-truth’ such observations.

“The advantage is that the spacecraft are simple and independent,” says Andy Cheng of Johns Hopkins, leading the AIDA project on the US side. “They can both complete their primary investigation without the other one.”

But by working in tandem, the quality and quantity of results will increase greatly, explains Andrés Gálvez, ESA AIDA study manager: “Both missions become better when put together – getting much more out of the overall investment.

“And the vast amounts of data coming from the joint mission should help to validate various theories, such as our impact modelling.”

Last week the 325 m Apophis asteroid passed close to Earth, and in mid-February the recently discovered 2012 DA14 space rock will pass closer than many satellites.

ESA is seeking to assess the impact hazard from Near-Earth Objects (NEOs) through its Space Situational Awareness (SSA) programme.

“AIDA offers a promising platform for the test and demonstration of different deflection methods,” adds Detlef Koschny, managing SSA’s NEO effort. “It is therefore important to ask the users early on what they’d like to do with a mission like this.”

For some time, ESA and its international partners have been studying missions to investigate asteroid deflection techniques.

The most popular concept involves a ‘hypervelocity impact’ – a collision at multiple kilometres per second, at such high speed that materials do not just shatter car-crash-style but are vaporised, turning even metal and solid rock into the hot soup of charged particles called plasma.

Such impact testing would help assess if asteroid deflection could be accomplished.

Increased knowledge of hypervelocity impacts would also have wider uses. Planetary scientists would gain fresh insight into our Solar System’s violent early history, including clues to the origin of life and the magnitude of extinction events.

And in practical terms, growing levels of orbital debris increases the risk of highly destructive hypervelocity impacts with critical satellite infrastructure or humans working in orbit. Studying this kind of impact will help to quantify the hazard and inspire protection techniques.

The AIDA Call for Experiment Ideas is being released on 1 February at http://www.esa.int/neo. For further information, see http://www.esa.int/Our_Activities/Technology/NEO/High_impact_factor_space_R_D_AIDA_Call_For_Experiment

Gold Rush

Two press releases from two different commercial ventures today, each announcing projects to mine for platinum and other minerals in space.

Seattle's own Planetary Resources debuted its program to mine near-earth asteroids for platinum and a water, and Moon Express in California unveiled their plan to mine the moon for the same things.

A while back I wrote about different scenarios which could lead to permanent colonization of other worlds within our solar system. At the time I specifically discounted off-world mining as a major motivator.

From December 13, 2010: "Mineral or other wealth has always been a strong motivator, but there's no reason to imagine that we'll experience a Lunar or Martian Gold-Rush anytime soon. Mars has plenty of iron, but so does earth, and earth's iron deposits are a lot closer."

So much for my powers of prognostication!

The rationale is that there are some single asteroids with more accessible platinum than all the platinum on the surface of the earth combined. My first thought on this is, if this works, I'm really glad I never invested in platinum. I'm just old enough to remember when amethyst was considered a precious gemstone, before the massive deposits were fund in Brazil. Now kids can buy fist-sized chunks of it in science-center gift shops with their baby-sitting money. If these commercial operations are successful, platinum could similarly cease to be a precious metal. But it might make a nice building material.

Will be posting much more about this, soon.

Going the distance

Scientific American this month has a very good article on some possibilities for NASA's manned space exploration program, written by two scientists involved in robotic deep-space exploration.

They proposed using a combination of the SLS chemical rockets or Delta IV heavy lift and Hall-effect ion drive spaceships to explore the moon, near-earth asteroids, Mars and Phobos. The argument for exploring near-earth asteroids was as a stepping stone for Mars and Phobos, and they were specifically looking at NEO 2008 EV5.

2008 EV5 follows a slightly oblique orbit very similar to earth's, and oscillates from about 1 AU (the distance from the sun to the earth) and 2 AU, at least in the immediate future. Mars at opposition is only about 0.5 AU from earth. My admittedly limited understanding of Hohmann transfer orbits is that a trip to 2008 EV5 or an earth-Trojan should take longer than a trip to Mars. Given that 2008 EV5 is only about 400 meters across, I must confess that I am at a loss to understand the wisdom of establishing 2008 EV5 as a waypoint to Mars. This is either a failing of my own understanding of how one navigates between two objects in different parts of the same orbit (very likely), or else NASA has other reasons for prioritizing a trip to 2008 EV5. My guess is that both are true; ie, I'm misunderstanding the geometry of a same-orbit Hohmann transfer, and NASA has more need of landing on 2008 EV5 than as a test-run for Phobos. My completely uneducated guess is that either NASA is more freaked out about near-earth asteroids than they let on, or that they want congress to think that they're more freaked out about near-earth asteroids than they let on. I lean toward the latter; perhaps at some point I'll bother to post my very own patented conspiracy theory on the subject. Anyway--

Based on the SciAm article and some of the recent posts here on candidates for outmigration, I created a graphic tonight to illustrate the relative distances of the different candidates being discussed. The planets, asteroids and moons themselves are not drawn even close to scale, but the relative distances between them is mostly right. The only exception to this is the distance between the earth and the moon, which is actually so small on the scale of the drawing that it could not be correctly shown at all. Also, the distances between Jupiter and her moons is completely erroneous, I simply included the Galilean moons to illustrate that the body depicted was in fact Jupiter.

1. The moon, and also the L4 and L5 Lagrangian orbits

2. Near-earth asteroid 2008 EV5, and also the earth-Trojans

3. Mars and Phobos

4. Ceres

5. Jupiter and Europa, Callisto and Ganymede

6. Saturn and Enceladus

It becomes apparent that Enceladus, intriguing though it is, is very, very far away. For a new home for our species, Ceres starts looking better all the time.

Horseshoes and hand-grenades

Tuesday, around 3:28pm pst, asteroid 2005 YU 55 is going to pass within the moon's orbit of us. A quarter of a mile (400 meters) in diameter, this is the largest asteroid to pass within the moon's orbit that we have ever known about (certainly lots of bigger ones have come even closer, we were just blissfully unaware of them). We have NEO's every single day, but this is one seriously big son of an accretion disk. If it were to actually hit the earth (don't worry, it won't, at least not in our lifetimes) the equivalent kinetic force would be greater than if every single nuclear warhead on every single missile on every single ballistic missile submarine in every single navy -- US, UK, France, Russia, China and India -- were to successfully detonate at the same location at the same time. Really. Which is still miniscule compared the the K/T asteroid which wiped out the dinosaurs (which was some 30 times larger), but, still, this is a big effing rock coming by tomorrow.

This will provide astronomers a very close view of a pretty large asteroid that we won't have to leave home to see, which is valuable. Nearly as useful, it serves as a not-so-subtle reminder that we really need to have the capability to intercept and deflect such objects all the time, not just whenever congress decides that it might be fun to budget for such things.

It will be visible from most of North America Tuesday evening, tracking from Aquila through Pegasus in about 10 hours time, but at a maximum visual magnitude of 11.2 it will require at least a 6" reflector telescope to see. Here's the track, from Sky and Telescope magazine:

Below is a very well done graphic from Space.com, with lots more information about this and other large NEOs --

NASA press conference on Near-Earth asteroid findings

Press release below, NASA press conference 10am PDT Thursday. New data from WISE satellite, will be interesting to see what they've found.

==================================================
Sept. 26, 2011

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown@nasa.gov

Whitney Clavin
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-4673
whitney.clavin@jpl.nasa.gov

MEDIA ADVISORY: M11-206

NASA TO HOST NEWS CONFERENCE ON ASTEROID SEARCH FINDINGS

WASHINGTON -- NASA will hold a news conference at 1 p.m. EDT on
Thurs., Sept. 29, to reveal near-Earth asteroid findings and
implications for future research. The briefing will take place in the
NASA Headquarters James E. Webb Auditorium, located at 300 E St. SW
in Washington.

NASA's Wide-field Infrared Survey Explorer (WISE) mission, launched in
December 2009, captured millions of images of galaxies and objects in
space. During the news conference, panelists will discuss results
from an enhancement of WISE called Near-Earth Object WISE (NEOWISE)
that hunted for asteroids.

The panelists are:
-- Lindley Johnson, NEO program executive, NASA Headquarters,
Washington
-- Amy Mainzer, NEOWISE principal investigator, NASA's Jet Propulsion
Laboratory, Pasadena, Calif.
-- Tim Spahr, director, Minor Planet Center, Smithsonian Astrophysical
Observatory, Cambridge, Mass.
-- Lucy McFadden, scientist, NASA's Goddard Space Flight Center,
Greenbelt, Md.

Reporters unable to attend may ask questions from participating NASA
centers or by telephone. To participate by phone, reporters must
contact Dwayne Brown at 202-358-1726 or dwayne.c.brown@nasa.gov by 10
a.m. EDT on Sept. 29.

The event will air live on NASA Television and the agency's website.
For NASA TV streaming video, downlink and scheduling information,
visit:

http://www.nasa.gov/ntv

The briefing also will be streamed live, with a chat available, at:

http://www.ustream.tv/nasajpl2

For more information about the mission, visit:

http://www.nasa.gov/wise

Missed again

NASA--
Near-Earth asteroid 2011 MD passed only 12,300 kilometers (7,600 miles) above the Earth's surface on Monday June 27 at about 1:00 PM EDT. The asteroid was discovered by the LINEAR near-Earth object discovery team observing from Socorro, New Mexico.

The diagram shows the trajectory of 2011 MD projected onto the Earth's orbital plane over a four-day interval. This small asteroid, only 5-20 meters in diameter, is in a very Earth-like orbit about the Sun. The incoming trajectory leg passed several thousand kilometers outside the geosynchronous ring of satellites and the outgoing leg passed well inside the ring.

19 near-Earth asteroids found in one night

The Pan-STARRS PS1 telescope on Haleakala, Maui, discovered 19 near-Earth asteroids on the night of January 29, the most asteroids discovered by one telescope on a single night. Cataloging near-Earth asteroids is important for astrobiologists who are trying to determine scenarios for the future or life on Earth if one of these rocks from space were to collide with our planet.

“This record number of discoveries shows that PS1 is the world’s most powerful telescope for this kind of study,” said Nick Kaiser, head of the Pan-STARRS project. “NASA and the U.S. Air Force Research Laboratory’s support of this project illustrates how seriously they are taking the threat from near-Earth asteroids.”

Pan-STARRS software engineer Larry Denneau spent that Saturday night in his University of Hawaii at Manoa office in Honolulu processing the PS1 data as it was transmitted from the telescope over the Internet. During the night and into the next afternoon, he and others came up with 30 possible new near-Earth asteroids.

Asteroids are discovered because they appear to move against the background of stars. To confirm asteroid discoveries, scientists must carefully re-observe them several times within 12-72 hours to define their orbits, otherwise they are likely to be “lost.”

The full story from Astrobiology magazine is here:
http://www.astrobio.net/pressrelease/3810/19-asteroids-bagged-in-one-night

More on object 1991VG

Here is the web page for the JPL small-body database for 1991VG, which is a possible Bracewell Probe candidate. My original post on this, titled The Sentinel, seems to be getting a lot of airplay, so I will be researching it further.

July of 2017 is our next launch window for either a crewed or robotic mission to 1991VG. Hopefully we'll have heavy lift capabilities available at that time.

Rock of Ages

Here we go again.

The asteroid 9994 Apophis is again in the news, because it, (wait for it!) still isn't going to hit the earth in 2029 or 2036.

1. Yes, there is a 100% probability that a massive asteroid or comet will collide with earth at some point in the future and cause the extinction of most life on earth. Again. And again. And again.

2. Yes, 9994 Apophis might, one day, far in the future, be one of the bodies which does so. And there will be others.

3. There are MANY asteroids which have a much higher chance of having a catastrophic collision with earth than 9994 Apophis. Probably the "best" candidate right now is  2011 AG5, but there are many others. Unfortunately, 2011 AG5 doesn't have a cool name like "Apophis", so the media doesn't really care.

4. There WILL be more data forthcoming on 9994 Apophis this year and in 2016 which will amplify our understanding of its trajectory, so it will certainly be in the news cycle yet again, but it is unlikely that this will reveal any significantly greater risk. As it stands right now, you are in much graver danger of winning the Washington State Lottery than you are of living to see 9994 Apophis collide with earth. If you happen to believe that you have a chance of winning the lottery, I would recommend that you send the money you would spend on lottery tickets to Strait of Magellan instead. There's at least some chance that I might feel guilty and send it back to you.

Naw.

5. If you're really excited about possible near-term Extinction Events that might actually wipe out all life on earth, your odds are much greater with global warming than with asteroids. Good enough, in fact, that with those odds I myself might buy a lottery ticket. Of course, I might not be around to spend my winnings.

Here's the real data on 9994 Apophis.

The Sentinel

In 1950 physicist Enrico Fermi, while considering the presumed ubiquity of technological civilizations around the Milky Way, over lunch one day asked the simple question, "Where are they?". By which he meant, even if advanced alien civilizations were exceedingly rare, if they existed at all some of them, even traveling at speeds of 5% of the speed of light (which may in fact prove to be about the maximum speed possible for space travel, which will be the subject of another post in the near future) or even slower, should eventually have colonized or at least visited all of the galaxy and already contacted us, either in person or by means of a probe of some sort. Meaning, the question of whether or not there are other technological civilizations in the Milky Way should be nonsensical; either there are none, or they're already here and downtown Seattle should look like Mos Eisley Spaceport. I mean, even more than it already does.

 The fact that earth is not already crawling with aliens (no disrespect intended to the Aldebaranian's mode of locomotion, its just an expression), combined with the lack of an unambiguous signal received by any of the SETI telescopes, is sometimes referred to as the Great Silence, or the Fermi Paradox.

I think this is from the brilliant comic XKCD, if you know otherwise please let me know!

There are a couple of possible explanations for this. The first is that there simply aren't any other technologically advanced civilizations in the Milky Way. As a generation which has grown up on a daily diet of science fiction, this seems ironically uncomfortable. But it may well be the case. Of the billions of species which have ever lived on earth we are the only one which has proven capable of space travel or radio broadcasts. Or any other technology more sophisticated than a digging stick or a broken rock. Life, even intelligent life, may well be ubiquitous, but technologically advanced civilizations may be vanishingly rare.

Another possibility is that interstellar space travel, either for reasons we do understand or for reasons we do not, may simply not be feasible. This is also uncomfortable for us, but it may be true. It is almost certainly true that crewed space travel will never exceed about 10% of the speed of light, for a variety of reasons (not the least of which being that by 12% of the speed of light, a grain of sand hitting the vessel would react with the force of a hydrogen bomb). But at 10% (or even 5%, which we have the technology to achieve right now) of the speed of light we could get to the nearest stars within a human lifetime. But there may be barriers to traveling through interstellar space which we haven't even considered.

Another possibility, one championed by UFO enthusiasts, is that our skies and streets ARE crawling with aliens, we just need to pull our heads out of our recta and realize it. This isn't quite as far-fetched as it sounds; some have posited that the natives in Hispaniola could not see Columbus's ships until their shamans or whatever they're called there did. This may be apocryphal, but it is true and demonstrable that the human mind filters out data it isn't prepared to process. If this sounds like BS to you, take this simple test here, and then come back to this post. My personal feeling is that this possibility is pretty unlikely, but I wanted to include it specifically because so many discussions of the Fermi Paradox willfully exclude it, which is simply bad science. 

Yet another possibility is that alien civilizations have visited here in the past, and then (tinkered with chimpanzi genes to invent us/used their antigravity technology to move around a bunch of rocks/put on funny hats and modeled for neolithic artists/figured we were beyond hope and left never to return/fill in the blank). This is also possible; there is an entire field of research called SETA, or the Search for Extraterrestrial Artifacts. SETA to date has not proven any more fruitful than SETI, with one possible exception which I'll talk about in a moment. In order for an artifact to be unambiguously "alien" it needs to be something truly beyond the abilities of human artificers to construct. For example, the pyramids at Cheops are amazing, but well within the capability of bronze-age builders if you happen to have many of them. If the pyramids had been made out of titanium, for example, THAT would be a pretty good indication that it was not built by bronze-age humans.

One type of artifact especially interesting to SETA researchers is something called a Bracewell Probe, first proposed by Ronald Bracewell in 1960. It is an autonomous robot probe used essentially as a message in a bottle to another star, which has crammed into its memory banks all of the information from and about the originating species that it's creators deemed worthy to put in it. If the probe happens to have the ability to utilize resources in other star systems to self-replicate, it is called a von Neumann probe and then has the ability to cover a lot more interstellar territory. Arthur Clarke, in his novel and then movie 2001: A Space Odyssey, imagined that an advanced alien civilization might send out millions of such probes to monitor promising worlds around the galaxy. Rather than try to analyze the development of each of the billions of species the probes were monitoring, the aliens set up a simple test. They placed a Bracewell probe on the moon. Any species on earth which advanced to the point of landing on the moon would find the probe, and trigger it to give the previously earthbound species further instructions.  

If you watched 2001 but didn't quite understand what was happening in that scene, or in any part of the movie, that's okay. Clarke was brilliant, and director Stanley Kubrick was brilliant, but the combination of the two of them was just effing weird.

So, we've been to the moon, and haven't found a Bracewell probe there. But oddly enough, we may actually have found one even closer than the moon.

On 6 November 1991 astronomer Jim Scotti discovered what he thought was a small near-earth object (asteroid), which was prosaically named 1991vg. NEO expert Duncan Steel at the University of Adelaide, Australia, analyzed 1991vg and made a truly startling discovery.  Based on the orbit of 1991vg, which trails the earth in its own orbit but sometimes closes range with earth for brief periods and then resumes its "station" behind it, and based also on the fact that light reflected from it indicates that the object is of a faceted nature (more like a shoebox than a basketball), there are three possible explanations for it. The first is that it is a naturally occurring asteroid. The second is that it is a piece of human-made space debris, left over most likely from the early Apollo missions. The third is that it is a self-propelled artifact of non-human origin. Through careful analysis and process of elimination, the third possibility has emerged as by far the most likely candidate. Really.

It is important to understand that Duncan Steel is probably the world's foremost expert of NEOs. He has written dozens of papers on various aspects of NEO research, and Steel and Scotti together have discovered and catalogued more NEOs than maybe all of the other researchers in the field combined. When Duncan Steel says "that's definitely not an asteroid and probably not human-made space junk", it's worthy of further investigation.

Here is his paper on the subject, in its entirety: SETA and 1991vg    

More research, obviously, must be done to determine the true nature of 1991vg. But if you happen to look up in the sky some night and see a giant baby swatting at satellites, don't say I didn't warn you.

Comet Hartley 2 Flyby

These photos are from the EPOXI spaceship's close flyby of comet Hartley 2 today. Comet Hartley 2 has been a bit of a disappointment visually from urban areas, but it has spawned some really beautiful low velocity meteors over the past several weeks, including one I blogged about recently (which I mistook for an Orionid).
Here's the NASA report. 

PASADENA, Calif. – NASA's EPOXI mission spacecraft successfully flew past comet Hartley 2 at 7 a.m. PDT (10 a.m. EDT) Thursday, Nov. 4. Scientists say initial images from the flyby provide new information about the comet's volume and material spewing from its surface.
"Early observations of the comet show that, for the first time, we may be able to connect activity to individual features on the nucleus," said EPOXI Principal Investigator Michael A'Hearn of the University of Maryland, College Park. "We certainly have our hands full. The images are full of great cometary data, and that's what we hoped for."
EPOXI is an extended mission that uses the already in-flight Deep Impact spacecraft. Its encounter phase with Hartley 2 began at 1 p.m. PDT (4 p.m. EDT) on Nov. 3, when the spacecraft began to point its two imagers at the comet's nucleus. Imaging of the nucleus began one hour later.
"The spacecraft has provided the most extensive observations of a comet in history," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at the agency's headquarters in Washington. "Scientists and engineers have successfully squeezed world-class science from a re-purposed spacecraft at a fraction of the cost to taxpayers of a new science project."
Images from the EPOXI mission reveal comet Hartley 2 to have 100 times less volume than comet Tempel 1, the first target of Deep Impact. More revelations about Hartley 2 are expected as analysis continues.
Initial estimates indicate the spacecraft was about 700 kilometers (435 miles) from the comet at the closest-approach point. That's almost the exact distance that was calculated by engineers in advance of the flyby.

Full Story

For those who wonder why NASA is spending so much money and effort determining the composition of comets and asteroids, this would be the answer. These two large asteroids passed well within the moon's orbit on the same day, September 8th of this year. Knowing as much as we can about asteroids and comets should be one of our very top priorities as a society. If you don't believe me, just ask a dinosaur.