NASA says its DART spacecraft caused a larger-than-expected change in the path of its target asteroid when they collided two weeks ago — marking a significant milestone in the effort to protect our planet from killer space rocks.
Before the crash, DART’s science team said they expected the collision to reduce the time it took for Dimorphos to go around Didymos by about 10 minutes. NASA would have regarded any change in excess of 73 seconds as a success.
After the crash, detailed observations from ground-based observatories showed that the orbit was actually 32 minutes shorter — going from 11 hours and 55 minutes to 11 hours and 23 minutes. That’s three times as much of a change as scientists were expecting. Scientists also said Dimorphos appears to be slightly closer to Didymos.
“This is a watershed moment for planetary defense, and a watershed moment for humanity,” NASA Administrator Bill Nelson said today. “All of us have a responsibility to protect our home planet. After all, it’s the only one we have.”
The Light Italian CubeSat for Imaging of Asteroids (LICIACube) has returned a series of close-up images of the asteroid Dimorphos, after last week’s successful impact of the Double Asteroid Redirect Test (DART) probe. LICIACube was built and operated by the Italian Space Agency (ASI), and was designed to capture post-impact imagery for the DART team, to help assess the effects of the impact.
There’s an old joke that the dinosaurs are only extinct because they didn’t develop a space agency. The implication, of course, is that unlike our reptilian ancestors, we humans might be able to save ourselves from an impending asteroid strike on Earth, given our six-and-a-half decades of spaceflight experience. But the fact is that while we have achieved amazing things since Sputnik kicked off the space age in 1957, very little effort thus far has gone into developing asteroid deflection technologies. We are woefully inexperienced in this arena, and aside from our Hollywood dramatizations of it, we’ve never yet put our capabilities to the test. But that’s about to change.
When a meteoroid enters the Earth’s atmosphere at a very high speed it heats up. This heating up produces a streak of light and is termed a meteor. When a meteor is bright enough, about the brightness of Venus or brighter, it becomes a fireball. Sometimes these fireballs explode in the atmosphere, becoming bolides. These bolides are bright enough to be seen even during the day.
Studying bolides as they pass through the atmosphere can help model larger asteroids, something of interest to the Planetary Defense Coordination Office (PDCO) which is run by NASA. These asteroids can be deadly if they are large enough, and learning how to predict their behavior is essential to protecting our planet from a devastating impact with long-term implications for the survival of many species on Earth.
Gazing at the night sky can evoke a sense of wonder regarding humanity’s place in the Universe. But that’s not all it can evoke. If you’re knowledgeable about asteroid strikes like the one that wiped out the dinosaurs, then even a fleeting meteorite can nudge aside your enjoyable sense of wonder. What if?
Luckily, planetary defence is at the top of mind for some scientists and engineers. One of those scientists is Professor Philip Lubin from the University of California Santa Barbara. Lubin is developing his idea called PI-Terminal Defense for Humanity. The PI stands for Pulverize It, and Lubin thinks pulverizing an incoming impactor into tiny pieces is our best bet to protect ourselves from an asteroid on short notice.
So far, the battle between life on Earth and asteroids has been completely one-sided. But not for long. Soon, we’ll have the capability to deter asteroids from undesirable encounters with Earth. And while conventional thinking has said that the further away the better when it comes to intercepting one, we can’t assume we’ll always have enough advance warning.
A new study says we might be able to safely destroy potentially dangerous rocky interlopers, even when they get closer to Earth than we’d like.
Using nuclear devices to deflect or disrupt an asteroid. Sounds a bit crazy, no? Maybe a little too Hollywood? And yet, detonating nukes in space may be necessary someday for the sake of planetary defense. In order for this method to be effective, scientists need to work out all the particulars in advance. That means knowing how much force will be necessary depending on the mass and trajectory of the asteroid.
Recently, a research collaboration between Lawrence Livermore National Laboratory (LLNL) and the Air Force Institute of Technology (AFIT) investigated how the energy output of a nuclear detonation could affect the path of an asteroid. This consisted of modeling different nuclear reactions (fission or fusion) to determine the neutron energy generated, which could potentially pave the way for a new type of asteroid redirect mission (ARM).
Next week, asteroid researchers and spacecraft engineers from all around the world will gather in Rome to discuss the latest in asteroid defense. The three-day International AIDA Workshop, which will run from Sept. 11th to 13th, will focus on the development of the joint NASA-ESA Asteroid Impact Deflection Assessment (AIDA) mission.
The purpose of this two-spacecraft system is to deflect the orbit of one of the bodies that make up the binary asteroid Didymos, which orbits between Earth and Mars. While one spacecraft will collide with a binary Near-Earth Asteroid (NEA), the other will observe the impact and survey the crash site in order to gather as much data as possible about this method of asteroid defense.
Finding examples of intelligent life other than our own in the Universe is hard work. Between spending decades listening to space for signs of radio traffic – which is what the good people at the SETI Institute have been doing – and waiting for the day when it is possible to send spacecraft to neighboring star systems, there simply haven’t been a lot of options for finding extra-terrestrials.
But in recent years, efforts have begun to simplify the search for intelligent life. Thanks to the efforts of groups like the Breakthrough Foundation, it may be possible in the coming years to send “nanoscraft” on interstellar voyages using laser-driven propulsion. But just as significant is the fact that developments like these may also make it easier for us to detect extra-terrestrials that are trying to find us.
Not long ago, Breakthrough Initiatives made headlines when they announced that luminaries like Stephen Hawking and Mark Zuckerberg were backing their plan to send a tiny spacecraft to Alpha Centauri. Known as Breakthrough Starshot, this plan involved a refrigerator-sized magnet being towed by a laser sail, which would be pushed by a ground-based laser array to speeds fast enough to reach Alpha Centauri in about 20 years.
In addition to offering a possible interstellar space mission that could reach another star in our lifetime, projects like this have the added benefit of letting us broadcast our presence to the rest of the Universe. Such is the argument put forward by Philip Lubin, a professor at the University of California, Santa Barbara, and the brains behind Starshot.
In a paper titled “The Search for Directed Intelligence” – which appeared recently in arXiv and will be published soon in REACH – Reviews in Human Space Exploration – Lubin explains how systems that are becoming technologically feasible on Earth could allow us to search for similar technology being used elsewhere. In this case, by alien civilizations. As Lubin shared with Universe Today via email:
“In our SETI paper we examine the implications of a civilization having directed energy systems like we are proposing for both our NASA and Starshot programs. In this sense the NASA (DE-STAR) and Starshot arrays represent what other civilizations may possess. In another way, the receive mode (Phased Array Telescope) may be useful to search and study nearby exoplanets.”
Using these as a template, Lubin believes that other species in the Universe could be using this same kind of directed energy (DE) systems for the same purposes – i.e. propulsion, planetary defense, scanning, power beaming, and communications. And by using a rather modest search strategy, he and colleagues propose observing nearby star and planetary systems to see if there are any signs of civilizations that possess this technology.
This could take the form of “spill-over”, where surveys are able to detect errant flashes of energy. Or they could be from an actual beacon, assuming the extra-terrestrials us DE to communicate. As is stated in the paper authored by Lubin and his colleagues:
“There are a number of reasons a civilization would use directed energy systems of the type discussed here. If other civilizations have an environment like we do they might use DE system for applications such as propulsion, planetary defense against “debris” such as asteroids and comets, illumination or scanning systems to survey their local environment, power beaming across large distances among many others. Surveys that are sensitive to these “utilitarian” applications are a natural byproduct of the “spill over” of these uses, though a systematic beacon would be much easier to detect.”
According to Lubin, this represents a major departure from what projects like SETI have been doing during the last few decades. These efforts, which can be classified as “passive” were understandable in the past, owing to our limited means and the challenges in sending out messages ourselves. For one, the distances involved in interstellar communication are incredibly vast.
Even using DE, which moves at the speed of light, it would still take a message over 4 years to reach the nearest star, 1000 years to reach the Kepler planets, and 2 million years to the nearest galaxy (Andromeda). So aside from the nearest stars, these time scales are far beyond a human lifetime; and by the time the message arrived, far better means of communication would have evolved.
Second, there is also the issue of the targets being in motion over the vast timescales involved. All stars have a transverse velocity relative to our line of sight, which means that any star system or planet targeted with a burst of laser communication would have moved by the time the beam arrived. So by adopting a pro-active approach, which involves looking for specific kinds of behavior, we could bolster our efforts to find intelligent life on distant exoplanets.
But of course, there are still many challenges that need to be overcome, not the least of which are technical. But more than that, there is also the fact that what we are looking for may not exist. As Lubin and his colleagues state in one section of the paper: “What is an assumption, of course, is that electromagnetic communications has any relevance on times scales that are millions of years and in particular that electromagnetic communications (which includes beacons) should have anything to do with wavelengths near human vision.”
In other words, assuming that aliens are using technology similar to our own is potentially anthropocentric. However, when it comes to space exploration and finding other intelligent species, we have to work with what we have and what we know. And as it stands, humanity is the only example of a space-faring civilization known to us. As such, we can hardly be faulted for projecting ourselves out there.
Here’s hoping ET is out there, and relies on energy beaming to get things done. And, fingers crossed, here’s hoping they aren’t too shy about being noticed!
Over the past month, about a half dozen rather large asteroids have careened nearby our home planet and in one case caused significant injury and property damage with no forewarning – showcasing the hidden lurking dangers from lackluster attitudes towards Asteroid Detection & Planetary Defense.
Now in a prescient coincidence of timing, NASA is funding an experimental asteroid radar detection array called ‘KaBOOM’ that may one day help thwart Earth’s untimely Ka-boom – and which I inspected first-hand this past week at the Kennedy Space Center (KSC),following the SpaceXFalcon 9 blastoff for the ISS.
“KaBOOM takes evolutionary steps towards a revolutionary capability,” said Dr. Barry Geldzahler, KaBOOM Chief Scientist of NASA Headquarters, in an exclusive interview with Universe Today.
If successful, KaBOOM will serve as a prelude to a US National Radar Facility and help contribute to an eventual Near Earth Object (NEO) Planetary Defense System to avert Earth’s demise.
“It will enable us to reach the goal of tracking asteroids farther out than we can today.”
First some background – This weekend a space rock the size of a city block whizzed past Earth at a distance of just 2.5 times the distance to our Moon. The asteroid – dubbed 2013 ET – is noteworthy because it went completely undetected until a few days beforehand on March 3 and measures about 460 feet (140 meters) in diameter.
2013 ET follows close on the heels of the Feb. 15 Russian meteor that exploded violently with no prior warning and injured over 1200 people on the same day as Asteroid 2012 DA 14 zoomed past Earth barely 17,000 miles above the surface – scarcely a whisker astronomically speaking.
Had any of these chunky asteroids actually impacted cities or other populated areas, the death toll and devastation would have been absolutely catastrophic – potentially hundreds of billions of dollars !
Taken together, this rash of uncomfortably close asteroid flybys is a wake-up call for a significantly improved asteroid detection and early warning system. KaBOOM takes a key step along the path to those asteroid warning goals.
‘KaBOOM’ – the acronym stands for ‘Ka-Band Objects Observation and Monitoring Project’ – is a new test bed demonstration radar array aimed at developing the techniques required for tracking and characterizing Near Earth Objects (NEO’s) at much further distances and far higher resolution than currently available.
“The purpose of KaBOOM is to be a ‘proof of concept’ using coherent uplink arraying of three widely spaced antennas at a high frequency; Ka band- 30 GHz,” KaBOOM Chief Scientist Geldzahler told me.
Currently the KaBOOM array consists of a trio of 12 meter wide radar antennas spaced 60 meters apart – whose installation was just completed in late February at a remote site at KSC near an alligator infested swamp.
I visited the array just days after the reflectors were assembled and erected, with Michael Miller, KaBOOM project manager of the Kennedy Space Center. “Ka Band offers greater resolution with shorter wavelengths to image smaller space objects such as NEO’s and space debris.”
“The more you learn about the NEO’s the more you can react.”
“This is a small test bed demonstration to prove out the concept, first in X-band and then in Ka band,” Miller explained. “The experiment will run about two to three years.”
Miller showed how the dish antennae’s are movable and can be easily slewed to different directions as desired.
“The KaBOOM concept is similar to that of normal phased arrays, but in this case, instead of the antenna elements being separated by ~ 1 wavelength [1 cm], they are separated by ~ 6000 wavelengths. In addition, we want to correct for the atmospheric twinkling in real time,” Geldzahler told me.
Why are big antennae’s needed?
“The reason we are using large antennas is to send more powerful radar signals to track and characterize asteroids farther out than we can today. We want to determine their size, shape, spin and surface porosity; is it a loose agglomeration of pebbles? composed of solid iron? etc.”
Such physical characterization data would be absolutely invaluable in determining the forces required for implementing an asteroid deflection strategy in case the urgent need arises.
How does KaBOOM compare with and improve upon existing NEO radars in terms of distance and resolution?
“Currently at NASA¹s Goldstone 70 meter antenna in California, we can track an object that is about 0.1 AU away [1 astronomical unit is the average distance between the Earth and the sun, 93 million miles, so 0.1 AU is ~ 9 million miles]. We would like to track objects 0.5 AU or more away, perhaps 1 AU.”
“In addition, the resolution achievable with Goldstone is at best 400 cm in the direction along the line of sight to the object. At Ka band, we should be able to reduce that to 5 cm – that’s 80 times better !”
“In the end, we want a high power, high resolution radar system,” Geldzahler explained.
Another significant advantage compared to Goldstone, is that the Ka radar array would be dedicated 24/7 to tracking and characterizing NEO’s and orbital debris, explained Miller.
Goldstone is only available about 2 to 3% of the time since it’s heavily involved in numerous other applications including deep space planetary missions like Curiosity, Cassini, Deep Impact, Voyager, etc.
‘Time is precious’ at Goldstone – which communicates with some 100 spacecraft per day, says Miller.
“If/when the proof of concept is successful, then we can envision an array of many more elements that will enable us to reach the goal of tracking asteroids farther out than we can today,” Geldzahler elaborated.
A high power, high resolution radar system can determine the NEO orbits about 100,000 times more precisely than can be done optically.
So – what are the implications for Planetary Defense ?
“If we can track asteroids that are up to 0.5 AU rather than 0.1 AU distant, we can track many more than we can track today.”
“This will give us a better chance of finding potentially hazardous asteroids.”
“If we were to find that a NEO might hit the Earth, NASA and others are exploring ways of mitigating the potential danger,” Geldzahler told me.
Kaboom’s ‘First light’ is on schedule for late March 2013.