Science behind the escape room
Well done on completing The Race to Space at DIAS Dunsink Observatory!
Now that you have cracked the puzzles in our escape room, here is a chance to explore a bit more about the science behind the puzzles and how this links to the research our teams do every day at Dunsink and DIAS.
This mission was only the second night launch in the history of NASA’s space shuttle program. The launch took place on the 26th of November 1985 and landed back in California on the 3rd of December 1985. The main objectives of the mission were to test the building of structures in space, along with the deployment of three communication satellites: Morelos-B, Aussat and RCA Satcom K-2 satellites.
Watch the post flight presentation here: https://www.youtube.com/watch?v=8JwvIpvzy8Y .
This was the 32nd mission for the Atlantis space shuttle, which had the purpose of delivering an integrated cargo carrier and a Russian-built mini research module to the International Space Station. While Atlantis was docked on the ISS, 3 spacewalks were completed. During these spacewalks a spare antenna and stowage platform were installed, batteries replaced for the Space Station’s P6 Truss which is used to store solar energy, and a power data grapple fixture was retrieved. The Russian research module was also installed on the Zarya module of the ISS.
Watch the mission highlights, including launch and landing: https://www.youtube.com/watch?v=BgM76yQrT8I .
The Expedition 5 mission was launched on the 5th of June 2002 and returned to Earth on the 7th of December 2002. Its purpose was to transport the Expedition 5 crew to the space station where they would take control for 185 days. During this period the crew installed extra Truss elements (used to support solar arrays), cooling radiators, a railroad to support the station’s Canadarm2 (a remote controlled mechanical arm), along with other equipment. Two spacewalks were done during the Expedition 5 mission. Research into areas such as bioastronautics, physical sciences, space product development, and space flight were conducted.
The STS-72 mission launched on the 11th of January 1966 and returned to Earth on 20th of January 1966. Using the Endeavour space shuttle the mission’s primary highlights were to retrieve a Japanese satellite, to deploy and retrieve a NASA science payload, as well as to complete two spacewalks. These two spacewalks were part of a series to prepare the space station for further mid-orbit construction. They performed several tests and evaluations on particular platforms and structures on the space station’s exterior.
Watch the mission highlights here: https://www.youtube.com/watch?v=MxSzkq2-ZmY .
In addition to this, Ireland, and in particular, DIAS has had many other notable contributions to space research. Denis O’Sullivan, a DIAS researcher in the School of Cosmic Physics, had several involvements with space research including the development of cosmic ray detectors on the Apollo 16 and 17 missions to the moon. Prof. O’Sullivan’s research was primarily focussed on understanding the effects of cosmic rays and the radiation of outer space. In a collaboration with the University of Berkley, Prof. O’Sullivan developed a way of studying the cosmic rays with a special type of plastic, this was chosen by NASA to be attached to the legs of the landing modules on the Apollo 16 and 17. This marked Ireland’s first space experiment. However, Prof. O’Sullivan continued his research and in 1976 was selected as a principal investigator, to develop an instrument to study the effects of cosmic rays on the Long Duration Exposure Facility (LDEF) that was placed in orbit by the Challenger spacecraft in 1984. It remained in orbit around Earth for a total of 69 months during which it collected the largest sample of cosmic ray chemical elements recorded to date. This provided the foundation for many other scientific studies which involved several post graduate students at DIAS. Following the launch of the International Space Station (ISS) in 1999, O’Sullivan was invited by NASA to study the effects of cosmic rays on humans while in orbit. He and his colleague, Dazhuang Zhou, made the first measurements of the charge spectrum of cosmic ray nuclei on the ISS between 2001 and 2003. Between 2005 and 2008 Prof. O’Sullivan and his team were chosen to study the effects of ultra-heavy nuclei on human tissue in space. They were part of the European Space Agency’s “Matroshka” mission, which involved putting a torso made of tissue equivalent material, and several instruments, both inside and outside of the ISS. Many studies have been carried out since, by Prof. O’Sullivan and other DIAS researchers, but goes to show the significance of his and DIAS’ involvement in space research.
With the moon being Earth’s closest neighbor there is plenty that we can study and learn about it, from its structure to its effect on the ocean’s tides. One interesting feature that we can measure very accurately is the distance between us and the moon. We do this by using a technique called Lunar Laser Ranging (LLR). By doing this we can measure the Earth-Moon distance up to an accuracy of one millimeter (approximately the thickness of a paperclip) and in doing so get a better understanding of the Moon’s motion around Earth, Einstein’s theory of relativity and much more.
The main principle behind lunar ranging is that by shining a laser at the moon and catching its reflection we can determine how far the light from the laser has travelled, and from that how far away the moon is. Since we know that light travels at a fixed speed (300 million meters per second), all that is needed to work out the Earth-Moon distance is to time how long it takes for the laser to come back to our detectors after being reflected by the moon. With our telescopes on Earth, we can generate very short bursts of light, each one tenth of a billionth of a second long, and point them at targets on the moon. We use such short bursts of light to make our measurements more accurate and reliable. There are multiple targets, known as retroreflectors, that are positioned on the moon that help reflect the laser pulses back towards Earth. Using highly accurate detectors the reflected laser pulses are picked up and their total travel time measured, with an accuracy of up to a few trillionths of a second. Usually, it takes the light 2.34 to 2.71 seconds to travel to the moon and back. With this information we now have enough to calculate how far the moon is from Earth. For the basis of the calculations, we use the following formula:
distance to moon = (speed of light × laser travel time)/2
We divide the result by two because the light travels the Earth-Moon distance twice, once on the way to the retroreflector, and once on the way back.
However, despite this, taking these measurements is quite challenging and many different factors need to be taken into account as they can have big effects on the results. Firstly, the light we use needs to travel in straight lines and not bend outwards or diverge like a flashlight does, because then the lasers are not as accurate, and they lose some of their energy in doing so. It is for this reason that lasers are used as they are the most collimated and precise method. Another factor to consider is the effect of our atmosphere on the path taken by the laser. Due to the way Earth’s atmosphere is made and is constantly changing, it distorts the laser beam and makes it diverge by up to a 1/3600th of a degree. This may seem very small, but since distances are so large it means the light can be 1.8 kilometers off of its target by the time it reaches the moon. As well as this, other factors such as the position of the Earth and Moon relative to the sun, how illuminated the moon is, and the alignment between the laser and reflector are needed to be taken into account. As a result, it is quite difficult to make these types of measurements. Generally one in 30 million photons (tiny light particles) will successfully be reflected by the retroreflector and captured by the detector back on Earth! Each laser pulse has 300 quadrillion photons in it, so in the end after everything up to 5 photons per laser pulse are expected to come back and be used by the detectors.
These types of measurements have helped us gain a big insight into the dynamics of the Earth-Moon system as well as into our own understanding of physics – particularly Einstein’s theory of general relativity. Using these measurements, we have discovered that the moon is spiraling away from Earth by 3.8 cm every year as well as other facts such as the existence of its fluid core.
However, in the early hours of the 3rd of October 1977 a fire broke out in the basement which was located below the Meridian room. The exact cause is unknown, but fire fighters believe the source to be an electrical fire. The fire destroyed the facility, and the fire debris was subsequently transported to the dump located just across the road from Dunsink observatory. It wasn’t until later that it was realised Dunsink’s moon rock had gone missing and that it was amongst the rubble that had been taken away. It is understood that the moon rock is still at the dump, lying under 4 decades worth of trash. Similar samples of moon rock have gone for sale for prices between tens of thousands of euros up to 3.8 million dollars, however the chances of finding the Dunsink moon rock’s today are described as being “worse than a needle in a haystack.”
These rays extend large distances and as a result, some material that originated in Tycho crater were returned to earth from the Apollo 17 mission. Dating analysis on these samples indicated that they were formed 108 million years ago. This is relatively young when compared to the 3.9-billion-year age of other lunar craters.
The magnetic fields generated by certain astronomical objects create a surrounding region in space, similar to cavity, which protects the object/planet from incoming cosmic radiation or solar wind. Earth’s magnetosphere protects us and all living organisms as well as our technology (including satellites) from the serious radiation and its effects from outer space. While these magnetic regions offer much protection, they are also very dynamic and are reliant on many different factors such as the interstellar and solar conditions as well as things such as the state of the planet’s core and its rotation. Due to all these factors the magnetosphere can be distorted by being pulled and stretched in different directions. The different structures of the regions and their interactions with the particles in outer space are particularly interesting to study and can provide insights into other fields such as electromagnetism and space weather.
In our solar system the Sun, Mercury, Jupiter, Saturn, Uranus, Neptune and Ganymede (one of Jupiter’s moons) all create and maintain their own magnetospheres. Jupiter has the strongest magnetosphere of all with it extending up to 7 million kilometers on the sun side, while it goes as far as Saturn’s orbit on the other side due to its interactions with the solar wind. Venus, Mars and Pluto don’t have an intrinsic magnetosphere and it is believed that this had a big role to play in their geological history and could be why Mars and Venus no longer have liquid water.
A wide variety of instruments and techniques are used when studying magnetospheres, both on the ground and in space. One way to study a magnetosphere is to measure its influence over a large region through remote sensing techniques. An example of this is observing the behavior and changes in the aurora (northern lights). These events are caused by the electrically charged particles from space interacting with Earth’s magnetosphere; since these occur mainly at high latitudes, they provide an overview of a large region of the magnetosphere and therefore can be interpreted as a proxy for the magnetosphere’s behaviour. Another method is to take in-situ measurements of variables such as the electric and magnetic fields as well as the charged or neutral particles in the regions. These are usually taken using satellites that orbit within the magnetosphere region. For Earth we have a large number of satellites in orbit which are taking measurements, on the other hand the other planets have a limited number of satellites which are able to take readings. In the case of Saturn, the Cassini spacecraft, which was in orbit for 13 years, was the main source of data on its magnetosphere, along with flybys of other missions. Jupiter’s magnetosphere was first studied by Pioneer 10 in 1973 and since then has been studied by several other missions such as Pioneer 11, Voyagers 1 and 2, Galileo and most recently the Juno New Frontiers mission. The Pioneer and Voyager missions also took measurements and gave an insight into Neptune and Uranus’ magnetospheres on their missions.
Come see the constellations through a telescope at one of our Public Visitor Nights!
The best viewing places to see the milky way, the stars and planets are those that are dark and unpolluted and not close to any major cities or towns; this is a must also for any observatories. Following on from the Celtic Tiger Ireland showed a 20% increase in its amount of light emitted, and since then with a larger population, especially in county Dublin, the levels of light pollution have continued to grow, making it difficult to appreciate and study the night sky. Fortunately, the conditions in Dunsink were appropriate for astronomical research in the 19th and 20th centuries and still to this day receives a relatively low amount of light pollution. The fields and land surrounding the site act as a type of buffer region for DIAS Dunsink observatory. On a clear night at Dunsink, you should be able to see most of the other planets in our solar system as well as several different constellations including Ursa Major, Cassiopeia, Pegasus and Orion, although some will depend on the time of year. Due to the location being considered a dark sky resort for the greater Dublin area, Dunsink regularly hosts star viewing and related activities in its area at night times.
While major cities and towns create problems for astronomical observations and casual viewing, another concern is the development of mega constellations. These are constellations composed of hundreds or thousands of man-made satellites that are put into orbit around the Earth. The most famous, which are already in production, and some of which have already been launched, are SpaceX’s Starlink, Amazon’s Kupier, and the OneWeb projects. These privately funded missions are designed to provide worldwide broadband internet but in doing so will put tens of thousands of satellites into orbit. This is and will continue to create problems for astronomical research that uses ground-based instruments, as these satellites interfere with measurements taken. Not only do they physically appear in photos and readings but also interfere indirectly by reflecting light from the sun towards Earth, if they aren’t positioned correctly. All three companies have reached out to astronomical societies and organisations to discuss how to limit the impacts that the mega constellations will have on astronomical research as well as star gazing.
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Images courtesy of Adam Quayle, 2021