The American space agency NASA has chosen an asteroid, to which American astronauts will be sent to meet in about 10 years. The agency announced last Thursday that the selected asteroid is designated 2011 MD. This celestial body periodically passes through its orbit in relative proximity to our planet. Using the powerful Spitzer orbiting telescope, the main characteristics of the asteroid were established. Its diameter is 6 meters, and its weight can be up to 100 tons. This asteroid has a very low density, which is explained by the structural features of 2011 MD. Currently, scientists suggest that this asteroid is either a "pile of stones" that are held together "due to gravitational or some other forces", or there are large voids inside it.
Finding the right asteroid
The search for a suitable asteroid was launched as part of the Asteroid Redirect Mission (ARM) program, which the US space agency announced in March 2013. One of the first targets of the observation was the small asteroid 2011 MD. Initially, scientists believed that its diameter was about 10 meters. This size made it an almost ideal object for an ARM program. The essence of the program is to "capture" and deliver an asteroid weighing up to 500 tons to the Earth's orbit. To observe the asteroid 2011 MD, the telescope's scientific team spent almost 20 hours.
The sensitivity, resolution and other characteristics of the Spitzer telescope are several times higher than that of many other infrared telescopes that are available to people today. Thanks to this telescope, American scientists were able to track how the asteroid 2011 MD was moving in its orbit, and also accurately determined its size and shape, mass and density. Even if scientists had high-quality images of this celestial body, it would be very difficult to find out all this. Mainly due to the irregular shape of the asteroid, and also for the reason that its manner of rotation around its own axis can change under the influence of heating of its surface, the pressure of sunlight and a number of other factors. In order to set all the parameters as accurately as possible, NASA scientists had to create a full-fledged computer model of the asteroid, which took about 10 hours of work to calculate with the help of a supercomputer.
As a result, it turned out that the asteroid 2011 MD is not at all similar to what astronomers imagined it to be in all previous years before its detailed study. In fact, this celestial body turned out to be significantly smaller than it looks. The diameter of the asteroid is only 6 meters, not 10, as previously thought. In addition, its mass and density were surprisingly low - about 50 tons and 1.1 grams per cubic meter. see Such data greatly surprised scientists, the obtained density values are more typical for the planets of the solar system - gas giants, which include Saturn or Jupiter, and not for rocky asteroids.
Scientists give two possible explanations for this, one of which is relatively "good", and the second is "bad" and is not very suitable for the implementation of the plans of the American space agency. In a "good" case, asteroid 2011 MD for the most part does not consist of rocky rocks, but of voids, which can occupy up to 65% of its volume. Figuratively speaking, from the inside, this asteroid may resemble a piece of good Swiss cheese with huge pores or a very loose heap of garbage. All this does not in any way interfere with NASA's plans to capture an asteroid by any spacecraft as part of the ARM project or to land an astronaut on its surface. In this case, the asteroid may have insufficient strength and simply fall apart during such operations with it.
If the "bad" scenario is confirmed, in which 2011 MD will not be a solid asteroid, but a kind of "swarm" consisting of microscopic dust particles that surround a dense core, the task will become more complicated. In this case, it would be much more difficult to capture the asteroid and deliver it to the lunar orbit. However, in any case, such studies can help scientists update their ideas and knowledge about microasteroids in the vicinity of our planet, to understand the reason for their appearance.
Spitzer Orbital Telescope
In addition to directly collecting scientific information and valuable samples for comprehensive analysis on Earth, NASA scientists have other plans for a microasteroid. Before sending a manned mission to it, scientists plan to change the orbit of this celestial body, forcing it to revolve around the natural satellite of our planet at an altitude of about 75 thousand kilometers above the lunar surface. For these purposes, the Americans expect to use a robotic spacecraft.
Manned flight to an asteroid
It is planned that already in 2019, an autonomous spacecraft will be sent to the asteroid 2011 MD, which will be able to throw a metal net on it (as the American engineers themselves say, “throw it into a bag”) and drag the asteroid into a stable near-lunar orbit. Around the middle of the 2020s, an already manned spacecraft with astronauts on board can be sent to this small asteroid.
Another scenario assumes that not the entire asteroid will be delivered to the Moon's orbit, but only a part of it - a large fragment the size of a large boulder. In this case, for the experiment, scientists will need a celestial body larger than 2011 MD. According to representatives of NASA, currently in the list of candidates for such an experiment includes 9 celestial bodies, but the search for new celestial objects is still ongoing.
NASA says it plans to finally choose one of the two proposed options by the end of 2014. By the end of this year, they plan to analyze various concepts for creating an automatic spacecraft, which will "set a trap" for the microasteroid. It is also assumed that the American astronauts will go to the asteroid itself on the Orion spacecraft, which is being developed by Lockheed Martin. To launch this manned vehicle, it is planned to use the SLS heavy launch vehicle, which is being created by another giant of the American aerospace industry - Boeing. The American space agency hopes that later this system can be used to carry people to Mars.
William Gerstenmeier, who holds the post of assistant director of NASA, noted last Thursday that the implementation of this project will help prepare a "manned flight into deep space", including to Mars, and will also serve to ensure the safety of our home planet from asteroid hazards. At the same time, a number of experts in the United States believe that this idea is unlikely to be justified from a financial, technical and scientific point of view. For this reason, Congressmen recently demanded from the space agency that NASA, after careful analysis, inform them how much it will cost to “capture the asteroid” and how it might affect other US space programs.
It is reported that about $ 100 million was allocated in the US space agency's budget for fiscal 2014 to find a suitable candidate among asteroids and to develop the necessary technologies. According to NASA experts, in general, the asteroid project will cost the treasury $ 1.25 billion, but independent experts warn that as a result, the cost of this program may be 2 times more.
