Hayabusa, or at least the part of it that was meant to survive atmospheric re-entry, has returned. Hayabusa, also known as MUSES-C, is a Japanese spacecraft, the first ever asteroid sample return mission. Unfortunately it is not yet clear if it has actually managed to collect any samples. Even so, it’s been one impressive mission.
Welcome home, Atlantis, for the very last time.
After being in service for a quarter century, her next trip is to a museum somewhere.
Sitting on the surface of Mars, a space probe that was not designed to survive the Martian polar winter did not survive the Martian polar winter. Not exactly a surprise.
The surprising bit is that another space probe orbiting Mars, designed to operate for two years but still working fine after four, has been able to snap high resolution pictures of Phoenix, which tell us what likely happened: the weight of carbon dioxide snow and ice broke Phoenix’s solar panels.
It is amazing that we have this kind of infrastructure around Mars.
Apollo 13, NASA’s “most successful failure”, was launched forty years ago today. One thing I didn’t know about the timing of the accident is the fact that the tank rupture occurred on the fifth stirring of the oxygen tank, which normally would have taken place 120 hours into the mission, when the lunar module was already on the Moon’s surface. Without the lunar module to serve as a lifeboat, the fate of the spacecraft would have been sealed. However, an unrelated sensor problem caused them to stir the tank more frequently, causing the accident to occur earlier.
Had the crew of Apollo 13 died in space, it has long been assumed that their spacecraft would have served as a frozen tomb for their bodies, orbiting the Sun. But now, some argue that the orbit of Apollo 13 was such that it would have returned to the Earth and burned up in the atmosphere just a few weeks later. I am not sure how you can really tell, with uncontrolled gas leaks, a tumbling spacecraft, and no precision radio-metric navigation data.
It was a rare night-time landing, but Endeavour is safely back home. The sight of an open flame from that venting on top, only visible at night, is positively weird: combined with the sound effects, it’s as if it was an overheated steam locomotive, not a space plane huffing and puffing on that runway.
Four more Shuttle flights to go, one of them by Endeavour. After that, for the first time since the 1960s, the United States will have no manned space flight capability. Hopefully not for long.
Steven Weinberg has an opinion piece on the Wall Street Journal Web site, where he expresses confidence that Obama’s NASA budget is the right one. Instead of wasting money on a manned space program that is self serving (i.e., other than putting men in space, it accomplishes nothing) more money will be available for doing real science, he thinks.
He has a point… but, well, but there is a but. Science is an important goal of the space program, but it’s not the only goal. As a matter of fact, if you ask me as a taxpayer why I think it’s a good idea to spend some tax dollars on the space program, scientific research is just one of the reasons I’d mention, and not even necessarily the first reason. People should travel in space because our future is in space. The steps we’re taking today may be baby steps, but they’re still important steps… even if a future with colonies on Mars, manned exploration of the outer planets and their moons, or perhaps travel beyond the solar system is decades, if not centuries away.
Having said that… the Constellation program, effectively repeating the accomplishments of Apollo with slightly upgraded hardware, may not have been the smart thing to do even if it had been funded right, which it wasn’t. Another footstep on the Moon is not the same as sustainable manned deep space exploration. If I recall, one of the Augustine commission’s suggestions was a deep space program without a specific landing objective; one that focuses on developing capabilities more than achieving spectacular “footstep-and-flag” milestones, “landing” only on asteroids, if at all, focusing instead on long-duration flights in deep space. If this is the space program Obama’s administration is about to establish, who knows? Perhaps he’s putting the space program on the track that it should have been put on decades ago. (Then again, perhaps I’m just an incurable optimist.)
As a footnote of sorts, I find it noteworthy that, more than 50 years after Sputnik, there is still only one nation on Earth with a comprehensive deep space research program: the United States. Much of the Soviet space program died an undeserved and premature death after the collapse of the Soviet Union; as to China, India, Japan, the EU and other nations, their efforts are commendable but that still leaves them in the “also ran” category.
Here’s a nice tennis ball, photographed from both sides:
It’s a big one, mind you, almost a thousand miles across. It’s Saturn’s moon Iapetus, famous because one side of it is significantly brighter than the other. The explanation, however, is more mundane than that offered in the book version of Clarke’s 2001: A Space Odyssey; the most recent hypothesis is that the discoloration is due to the thermal migration of ice.
This is the year when the Soviet spaceship Alexei Leonov was supposed to fly to Jupiter, investigating the failure of the spaceship Discovery and the death of her crew nine years earlier. At least in one respect, Clarke’s vision will come true: after the Space Shuttle’s planned retirement later this year, the United States will be left without a manned launch capability, and American astronauts will be ferried to the International Space Station (alas, a mere few hundred kilometers above the Earth’s surface, not a billion kilometers from here like Jupiter) on board Russian spacecraft. Not exactly an inspiring thought, except perhaps to some Russians.
Unlucky Friday the 13th it is not, at least not for NASA; they just announced that the much maligned LCROSS impact mission has, after all, found water on the Moon.
Does this mean that I might yet live long enough to see a permanent manned lunar base come into existence?
Some Romanians are planning to fly a balloon to the Moon. OK, to be more precise, what they’re planning is the use of a stratospheric balloon as a launch platform for their attempt to win Google’s Lunar X Prize. It’s not as crazy as it sounds… the disadvantages of launching from an unstable platform like a balloon may be more than offset by the advantages of launching from an altitude that is above most of the Earth’s atmosphere.
It appears that the test launch of NASA’s Ares I-X rocket was successful. This is very good news indeed.
Canadian astronaut Julie Payette is safely back on terra firma. During the post-mission press conference, she described the environment in which the International Space Station has been constructed, i.e., space, as “one of the most hostile”.
But… is it?
The funny thing is, while the human body is not designed to survive in space, if you suddenly found yourself floating outside the ISS, you’d have several seconds of useful consciousness before passing out. Further, if you managed to get back in before too many seconds have passed, you might survive the experience with only minor wear and tear and no permanent damage. (Yes, that infamous scene in 2001: A Space Odyssey is scientifically plausible.)
Compare this to the bottom of the ocean. How long would you survive under a pressure of several hundred atmospheres? Or consider the crater of an active volcano. How many seconds of consciousness would you enjoy before your body is vaporized?
And then I have not even considered something like the surface of the Sun (not to mention its interior.) Talk about hostile!
The thing is, space is hostile alright, but we are creatures of the near vacuum: we can briefly survive in vacuum, even return from it without major injury. Even for our machines, it’s much easier to survive in space than it is to survive elsewhere. Perhaps this should be seen as encouraging… once we master the challenge of getting out of the Earth’s gravity well economically, living in space may not be as hard as it sounds.
I was 6 years old 40 years ago today, visiting family in Romania with my parents. I did not really appreciate this moment (hey, I already read Jules Verne, isn’t going to the Moon a perfectly natural thing to do?) but I did see the first landing of a human being on another celestial body on television.
As Larry Kellogg said in his lunar-update newsletter, people who didn’t believe before that the Moon landing happened are unlikely to be convinced by this, but it’s still darn nice to be able to see nearly 40-year old footsteps on the Moon from orbit:
Apollo 14 footsteps
Forty years ago this morning, Apollo 11 was launched: Neil Armstrong and Buzz Aldrin were on their way to land at Mare Tranquilitatis, in the most significant journey in human history to this date.
The scary part is that this year also marks the 37th anniversary of the last trip to the Moon, indeed the last voyage by a human being beyond low Earth orbit.
I was only 6 when Armstrong and Aldrin landed on the Moon, and I had no doubt in my mind that by the time I turn 46, there would be people on the Moon, on Mars, possibly on select satellites of Jupiter and Saturn, perhaps even on their way to the stars.
Now that I am 46, I am doubtful that I will live long enough to see another human fly beyond low Earth orbit. This is not a pleasant thought. Perhaps I’ll be lucky enough to live another 40 years in good physical and mental health, and get a chance to be proven wrong.
Until then, I keep dwelling on the irony of the fact that nowadays, most of the documentaries you can find on manned deep space missions and exploration of the Moon are aired on the History Channel.
Given the less than perfect record of the Ariane 5 launch vehicle, there was reason for concern given that two new great observatories, Herschell and Planck, were launched on the same rocket this morning. Fortunately, the launch was successful, and both spacecraft are now on their merry way. Herschell is an infrared/submillimeter wavelength telescope, while Planck is “WMAP on steroids”, expected to provide much higher resolution views of the cosmic microwave background than its predecessor.
The space shuttle Atlantis is on its way to the Hubble Space Telescope. If the planned repairs are successful, Hubble may get another five years or more before it has to be decommissioned. Originally, the plan was to return it to the Earth, but in the wake of Columbia, that has been deemed to risky… now, it will be deorbited, to ensure that its large mirror (which is not expected to burn up in the atmosphere) doesn’t fall on an inhabited area. But hopefully, that is still many years away.
I saw the package that is now in the belly of Atlantis when I was at Goddard last summer. Well, maybe not quite the same package as, after the repair mission was postponed, I believe they added a few bits to it, but still, it’s largely the same.
Sadly, this mission may also be the very last really useful mission of the shuttle fleet. That is not to say that they won’t fly several more missions… but they are all to the International Space Station, and while I am an enthusiastic supporter of manned space exploration, flying meaningless circles in low Earth orbit just isn’t it… it’s a waste of money, and a pointless risk to the astronauts’ lives.
North Korea’s news agency informs us that the satellite their country launched overnight is orbiting normally, transmitting immortal revolutionary songs.
Too bad that according to NORAD, the launch vehicle’s second and third stages, along with the payload, are at the bottom of the Pacific ocean.
I often get questions about the Pioneer anomaly and our on-going research. All too often, the questions boil down to this: what percentage of the anomaly can <insert theory here> account for?
This is a very bad way to think about the anomaly. It completely misses the fact that the Pioneer anomaly is not an observed sunward acceleration of the Pioneer spacecraft. The DATA is not a measured acceleration; what is measured is the frequency of the spacecraft’s radio signal.
I already capitalized the word DATA in the previous paragraph; let me also capitalize the words MODEL and RESIDUAL, as these are the right terms to use when thinking about the Pioneer anomaly.
As I said above, the DATA is the Doppler measurement of the spacecraft’s radio frequency.
The MODEL is a model of all forces acting on the spacecraft including gravity, on-board forces, solar pressure, etc; all effects acting on the spacecraft’s radio signal, including the Shapiro delay, solar plasma, the Earth’s atmosphere; and all effects governing the motion of the ground stations participating in the communication.
The RESIDUAL is the error, the difference between the MODEL’s prediction of the Doppler measurement vs. the actual measurement. This RESIDUAL basically appears as noise, but with characteristic signatures (a diurnal and an annual sinusoid along with discontinuous jumps at the time of maneuvers) that suggest mismodeling.
The goal is to make this RESIDUAL “vanish”; by that, we mean that only random noise remains, any diurnal, annual, or maneuver-related signatures are reduced to the level of background noise.
The RESIDUAL can be made to vanish (or at least, can be greatly reduced) by incorporating new contributions into the MODEL. These contributions may or may not be rooted in physics; indeed, orbit determination codes typically have the ability to add “unmodeled” effects (basically, mathematical formulae, such as a term that is a quadratic or exponential function of time) to the MODEL, without regard to the physical origin (if any) of these effects.
Anderson et al. found that if they add an unmodeled constant sunward acceleration to the MODEL, they can make the RESIDUAL vanish. This is the result that has been published as the Pioneer anomaly.
If one has a physical theory that predicts a constant sunward acceleration, it is meaningful to talk in terms of percentages. For instance, one may have a physical theory that predicts a constant sunward acceleration with magnitude cH where c is the speed of light and H is Hubble’s constant at the present epoch; it then makes sense to say that, “using the widely accepted value of H ~= 71 km/s/Mpc, the theory explains 79% of the Pioneer anomaly,” since we’re comparing two numbers that represent the same physical quantity, a constant sunward acceleration.
However, note (very important!) that the fact that a constant sunward acceleration fits the data does not exclude alternatives with forces that are not constant or sunward pointing; the DATA admits many different MODELs.
Now let’s talk about the thermal recoil force. It is NOT constant and it is NOT sunward pointing. As we recompute this force, incorporating the best thermal model that we can compute into the MODEL and re-evaluate it, we obtain a new RESIDUAL. There are, then, the following possibilities:
Instead of playing with percentages, it makes a lot more sense to do this: after applying our best present understanding insofar as thermal recoil forces are concerned, we re-evaluate the MODEL. We compute the RESIDUAL. We check if this residual contains any signatures of mismodeling. If it doesn’t, we have no anomaly. If it does, we characterize this mismodeling by applying various unmodeled effects (e.g., a constant sunward force, exponential decay, etc.) to check if any of these can characterize the RESIDUAL. We then report on the existence of a (revised) anomaly with the formula for the unmodeled effect as a means to consisely characterize the RESIDUAL. If this revised anomaly is still well described by a constant sunward term, we may use a percentage figure to describe it… otherwise, it’s probably not helpful to do so.
This is a sad picture:
It's raining Columbia
Yesterday, NASA released its final report about the Columbia accident, complete with gruesome but necessary details about how seven astronauts died.