Astonauts have successfully installed a new pump in the U. S. segment of the ISS cooling system. The task took three spacewalks, rather than the originally scheduled two, to complete.
Getting the cooling system operating again is critical for the long term use of ISS, and installing the pump is a big step forward. Working out what was necessary to repair a major spacecraft system will also give NASA valuable experience as it looks to planning deep space missions.
Monday, August 16, 2010
Saturday, August 14, 2010
SETIcon
This weekend in California's Silicon Valley, the SETI Institute hosts SETIcon, a public event modeled on science fiction conventions, to mark fifty years of searching for extraterrestrial intelligence. SETIcon will feature not only scientists and engineers who have helped make SETI a respected scientific endeavor, but actors and sci-fi authors as well-- those who have dealt with aliens in the realm of human imagination.
Of course, SETI has so far failed in its search, though there have been a few interesting incidents. The truth is, however, that for most of that fifty years SETI searches were weak and sporadic. Now, there is a radio telescope array primarily used for SETI, searches have become more robust with better technology, search strategies have become more sophisticated, and researchers are moving beyond radio to include optical searches for lasers, for example.
After a few decades to establish itself and lay the foundation of its field, SETI seems to be growing into itself, finally becoming able to pursue its goal systemically.
Of course, SETI has so far failed in its search, though there have been a few interesting incidents. The truth is, however, that for most of that fifty years SETI searches were weak and sporadic. Now, there is a radio telescope array primarily used for SETI, searches have become more robust with better technology, search strategies have become more sophisticated, and researchers are moving beyond radio to include optical searches for lasers, for example.
After a few decades to establish itself and lay the foundation of its field, SETI seems to be growing into itself, finally becoming able to pursue its goal systemically.
Friday, August 13, 2010
Neptune Trojan
Astronomers have discovered the first asteroid in the L-5 position in the orbit of Neptune. The L-5 refers to a point in space at which the gravitational influences of Neptune and the Sun balance, which means a body in that slot will tend to remain there indefinitely. It turns out there are five such points in a two-body gravitational arrangement.
Estimates are the asteroid discovered is about 60 miles across and may be one of 150 in the L-5 area. A similar swarm has already been discovered occupying Neptune's L-4 region. Jupiter and Saturn also have asteroids in the corresponding areas of their orbits. Astronomers call such asteroids "Trojans." Bodies at the L-5 and L-4 points have the same orbit as the planet-- Neptune, in this case-- but are 60 degrees ahead of the planet and 60 degrees behind it in the orbit.
The stability at all five of the points make them attractive places to park spacecraft and eventually establish bases. With so many asteroids, and thus so much raw material already there, when humans venture into the realm of the gas giants, major bases may well be established at these points, leading us ever deeper into space.
Estimates are the asteroid discovered is about 60 miles across and may be one of 150 in the L-5 area. A similar swarm has already been discovered occupying Neptune's L-4 region. Jupiter and Saturn also have asteroids in the corresponding areas of their orbits. Astronomers call such asteroids "Trojans." Bodies at the L-5 and L-4 points have the same orbit as the planet-- Neptune, in this case-- but are 60 degrees ahead of the planet and 60 degrees behind it in the orbit.
The stability at all five of the points make them attractive places to park spacecraft and eventually establish bases. With so many asteroids, and thus so much raw material already there, when humans venture into the realm of the gas giants, major bases may well be established at these points, leading us ever deeper into space.
Thursday, August 12, 2010
Adding Spacewalks
Astronauts successfully removed the broken pump in the ISS cooling system yesterday, but the job is proving to be bigger than NASA had first thought. The space agency is now saying four spacewalks, twice the original number, will be required to do the job.
The third spacewalk is scheduled for sometime next week. NASA is being careful to get the repair process right, and to avoid overtaxing either the ISS crew or the engineers on the ground working to develop the techniques and procedures the spacewalkers will use.
NASA has that option now because the backup cooling system in the U. S. part of ISS and the Russian system in the Russian part are both working well. If one of those falters, however, the pressure will be on to get these repairs finished quickly.
The third spacewalk is scheduled for sometime next week. NASA is being careful to get the repair process right, and to avoid overtaxing either the ISS crew or the engineers on the ground working to develop the techniques and procedures the spacewalkers will use.
NASA has that option now because the backup cooling system in the U. S. part of ISS and the Russian system in the Russian part are both working well. If one of those falters, however, the pressure will be on to get these repairs finished quickly.
Wednesday, August 11, 2010
Tranquility To An Asteroid?
A group at NASA is looking at the possibility of using the Tranquility module installed on ISS in February as the core of a ship to take astronauts to an asteroid in 2025. Tranquility would be removed from ISS after 2020, fitted with a propulsion and guidance unit and perhaps with inflatable modules like the ones being pursued by Bigelow Aerospace. The inflatable modules would add living areas for the crew.
It's an interesting idea. For one thing, the proposal seems to recognize that flying weeks- or months-long missions in a capsule is impractical. Deep space ships will of necessity be large, multi-module vehicles that are assembled in Earth orbit. Because of their size and cost, such ships should also be designed to fly several deep space missions, not just one.
By 2020, however, the situation in manned space could be radically different than it is today. Several space stations built with Bigelow's inflatable technology could be in Earth orbit. In that case, building a deep space ship using BA's technology for the entire ship might be the obvious way to go. By then, too, private companies may have established lunar bases. Both BA and Interorbital Systems, for example, are looking at precisely that. In such circumstances, NASA may have more options for manned deep space exploration than we can currently imagine.
It's an interesting idea. For one thing, the proposal seems to recognize that flying weeks- or months-long missions in a capsule is impractical. Deep space ships will of necessity be large, multi-module vehicles that are assembled in Earth orbit. Because of their size and cost, such ships should also be designed to fly several deep space missions, not just one.
By 2020, however, the situation in manned space could be radically different than it is today. Several space stations built with Bigelow's inflatable technology could be in Earth orbit. In that case, building a deep space ship using BA's technology for the entire ship might be the obvious way to go. By then, too, private companies may have established lunar bases. Both BA and Interorbital Systems, for example, are looking at precisely that. In such circumstances, NASA may have more options for manned deep space exploration than we can currently imagine.
Tuesday, August 10, 2010
ET Hypotheses
Physicist Enrico Fermi famously asked "Where are they?" when discussing the possibility of extraterrestrial civilizations. His point was simple. If a civilization in the Milky Way had achieved spaceflight even a million years ago-- not long in cosmic terms-- it would have had time to spread throughout the galaxy. They should be here. Since Fermi had no evidence of that, he concluded there likely were no mature, spacefaring civilizations in the galaxy.
UFO researchers disagree there is no evidence, but they have yet to produce a single smoking gun. SETI researchers are also looking for evidence in the form of electronagnetic transmissions that can be picked up across interstellar space. A few interesting possibilities have been found, but nothing has been confirmed.
There have also been hypotheses to counter Fermi's question. The Zoo Hypothesis holds that Earth is being watched by ETs much as we watch animals in a zoo. A similar idea, the Quarantine Hypothesis, argues that Earth has been put off-limits by ETs to allow humanity to develop as we will. A third, the Jungle Hypothesis, suggests that ETs are around and are not particularly trying to hide from us, but they operate at such a different level that we are unlikely to come in contact with them, much as a given ant in a jungle is unlikely to ever come across a human even though humans don't try to hide from ants.
All these attempts to deal with Fermi's simple question suffer from the same basic weakness. They lack evidence to support them. They are, therefore, at least for the moment, more philosophical constructs than scientific hypotheses. That could change in a moment, of course, perhaps especially in the case of SETI, where researchers are pursuing plausible strategies in a systematic way. Until that new moment, however, all we can really say about the possibility of other civilizations in this galaxy is absence of evidence is not evidence of absence.
UFO researchers disagree there is no evidence, but they have yet to produce a single smoking gun. SETI researchers are also looking for evidence in the form of electronagnetic transmissions that can be picked up across interstellar space. A few interesting possibilities have been found, but nothing has been confirmed.
There have also been hypotheses to counter Fermi's question. The Zoo Hypothesis holds that Earth is being watched by ETs much as we watch animals in a zoo. A similar idea, the Quarantine Hypothesis, argues that Earth has been put off-limits by ETs to allow humanity to develop as we will. A third, the Jungle Hypothesis, suggests that ETs are around and are not particularly trying to hide from us, but they operate at such a different level that we are unlikely to come in contact with them, much as a given ant in a jungle is unlikely to ever come across a human even though humans don't try to hide from ants.
All these attempts to deal with Fermi's simple question suffer from the same basic weakness. They lack evidence to support them. They are, therefore, at least for the moment, more philosophical constructs than scientific hypotheses. That could change in a moment, of course, perhaps especially in the case of SETI, where researchers are pursuing plausible strategies in a systematic way. Until that new moment, however, all we can really say about the possibility of other civilizations in this galaxy is absence of evidence is not evidence of absence.
Monday, August 9, 2010
Visiting An Asteroid
This week, NASA will host a conference bringing together experts from government, academia, industry, and the international community that will focus on what is required to send humans to a near-Earth asteroid. President Obama has already called for such a flight by NASA by 2025, even though Congress has yet to endorse his plan.
Such a flight would expand human spaceflight capability and do good science, but another factor likely to be put forward in support of such a mission is its contribution to planetary defense. We know it's only a matter of time before Earth is hit once again by an asteroid or comet big enough to threaten our very existence. To counter that threat, we need to know more about those bodies than we do at present, and a human flight to one would help focus public attention and funds on preparing to deflect dangerous bodies away from Earth.
A possible question might also be whether one human flight would be sufficient. We know all asteroids are not the same, so human flights to various bodies, each representing a different category of asteroid, might make sense. Such a program could also build towards human missions to Mars in a systematic way.
Such a flight would expand human spaceflight capability and do good science, but another factor likely to be put forward in support of such a mission is its contribution to planetary defense. We know it's only a matter of time before Earth is hit once again by an asteroid or comet big enough to threaten our very existence. To counter that threat, we need to know more about those bodies than we do at present, and a human flight to one would help focus public attention and funds on preparing to deflect dangerous bodies away from Earth.
A possible question might also be whether one human flight would be sufficient. We know all asteroids are not the same, so human flights to various bodies, each representing a different category of asteroid, might make sense. Such a program could also build towards human missions to Mars in a systematic way.
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