Tag Archives: Solar System


by Móeiður Þorvaldsdóttir

NASA is planning for its top priority manned mission to Mars to be accomplished by the mid-2030s. This will follow three exploratory missions meant to investigate the long-term viability of humans surviving on Mars. Furthermore, these missions are necessary to develop and test necessary systems and equipment such as life support and spacecraft controls. These missions rely on the completion of NASA’s Space Launch System (SLS), the construction of which began in November 2014. SLS is a launch vehicle that will pave the way for more massive payloads than ever before. The manned mission is divided into two stages: the first one is planned to reach Mars’ moon Phobos by 2033 whilst the second part is expected to reach the surface of Mars by 2039.

A mosaic of Mars created from over 100 images taken by Viking Orbiters in the 1970s. Valles Marineris, the canyon seen in the centre, is the largest canyon in the Solar System. Image credit: NASA

The Plan

The three exploratory missions are named Earth Reliant, Proving Ground, and Earth Independent. Earth Reliant has already begun and is expected to continue until 2024. Proving Ground will start in 2018 when the Orion spacecraft will be launched on a lunar orbit using the SLS. The SLS in combination with other spacecraft has the capacity to help astronauts travel farther into space than ever before. The SLS has also been proposed as a launch vehicle for Uranian probe and Solar Probe 2, missions to Uranus and the Sun currently being planned. Orion’s first trip to the Moon will be unmanned, but, if this unmanned mission is successful astronauts will man Orion on a similar journey. This stage will test the capabilities of NASA’s team of astronauts, scientists and engineers as they attempt to redirect an asteroid into lunar orbit and extract samples for testing upon arrival back on Earth. Earth Independent will start with an unmanned trip to Mars in the 2020s that will test the capabilities of the vehicle for entry, descent and landing. It will also provide an opportunity to collect samples from the surface of Mars. This is NASA’s final exploratory mission, after which astronauts will begin their journey to the Red Planet.

Reaching Phobos

The trip to Phobos will require four launches of the SLS. The first of the four launches will carry a space tug which will use Solar Electric Propulsion (SEP) and two chemical propulsion payloads. The chemical propulsion payloads will be used to get the vehicle out of Earth’s influence and to land the vehicle on Phobos. The second SLS stage is planned to carry another SEP tug and the Phobos base. The Phobos base will be settled in order to provide a habitat for humans once on Phobos. It would also be possible to transport the base to different locations on Phobos if required. The next SLS launch will carry a deep-space habitat that is similar to the Phobos’ base as well as launch the vehicle into orbit around Mars. Finally, the last SLS stage will send a crew of four astronauts to Mars on board Orion. The Phobos Transfer Stage will ferry the astronauts down to the base in 2033 where they will remain for about 300 days. The astronauts will then return to Earth.

The Orion flight test crew module. Image credit: NASA

The Trip to Mars

Getting astronauts onto the surface of Mars will involve a further six SLS launches. This final part of the mission involves getting a lander in orbit around Mars. The lander will include a Mars Ascend Vehicle that would bring the astronauts to Mars’ surface and then back to earth. The vehicle will be equipped with retrorockets and a drag-increasing Supersonic Inflatable Aerodynamic Decelerator (SIAD) instead of the older parachutes that offer less drag. The lander will support a crew of 2 for 28 days or 4 for 6 days.

Possible Complications

A manned mission to Mars is not an easy feat as there are many things that can go wrong. NASA will rely heavily on the ISS for gathering more information regarding possible health risks of the astronauts and for the testing of equipment. It is necessary to construct Orion in such a way that the astronauts are safe from radiation in interplanetary space, as well as preserving their muscles, bones and internal organs in microgravity for a long period of time. A 300 day stay on Phobos, a moon that has a gravitational pull equivalent to 0.05% of the Earth’s may impact astronaut’s bodies due to loss of muscle mass and bone density. Furthermore, for a trip to such a distant destination, there must be no flaws in any of the launch systems, propulsion systems or space tugs. All systems involved must be tested rigorously before they can be used in order to prevent any complications. Even with the many precautions taken and with rigorous testing, an unmanned mission is necessary prior to the manned missions at each stage in order to minimize the risk of things going wrong.

Humanity has not ventured beyond low-Earth orbit since the Apollo 17 mission. This will be the next big step in space exploration and may be the beginning of humans colonising other planets. Moreover, this will offer the opportunity to study the surfaces of Mars and Phobos further as well as the effects of space travel on human anatomy. If this series of missions is successful, NASA’s scientists hope this will mark the beginning of regular missions to Mars.

Artist concept of NASA’s Space Launch System (SLS) 70-metric-ton configuration launching to space. Image credit: NASA

The Mystery Spots of Ceres

by Ioana Boian (edited by Andrew Blance)

How did the Solar System form? How did water originate on Earth? These are some of the questions that researchers studying distant icy objects in the outskirts of our Solar System are trying to answer. By investigating Ceres, a small dwarf planet in the asteroid belt, they hope to shed some light on these mysteries.

Image of Ceres (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Ceres arose naturally as a target for observation because of its unique status: it is the largest object in the asteroid belt and the sole dwarf planet in the inner Solar System. Remarkably, it is also known to have an icy mantle and may even have an internal ocean of liquid water. It has even been proposed that under a slightly different set of circumstances Ceres could have evolved into a planet similar to Earth and Mars. Dawn, a spacecraft sent to study dwarf planets, approached this fascinating place in 2015 and sent images home, inspiring further research into the dwarf planet. The images revealed two bright spots on its surface which have proven difficult to explain.

Dawn was launched in 2007. It is not only the first spacecraft to orbit a main belt asteroid but also the first to orbit two extra-terrestrial bodies. The Dawn mission targets both Ceres and Vesta, rocky bodies in the asteroid belt which may hold answers about the early Solar System and its formation. Following the assumptions that Vesta is rocky and Ceres contains large quantities of ice these two bodies provide a bridge between the formation of the inner rocky Solar System and its outer icy parts. Vesta was reached in 2011 and the mission results revealed important new information about its craters and their formation, chemical composition and gravity. The landscape of Vesta was even shown to be surprisingly similar to Mars, or even Earth. Although there are theories that, like Ceres, a pocket of ice exists under the surface, these ideas are still under debate. While a significant amount of data was gathered about Vesta, the more fascinating mysteries involve Dawn’s other target, Ceres.

In 2003 a single shining spot was observed on Ceres by the Hubble Space Telescope, but the discovery was dismissed, believed to be caused by the poor resolution of the image. Later in 2015, Dawn provided more detailed images that proved the spot to be real. It was revealed that the one spot was actually many, and since then several of these groupings of spots have been detected.

Image of Spots Found In Ceres’ Occator Crater. (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

The main theory proposed by NASA was that sunlight was hitting reflective material found in the crater where the spots were located. The high albedo of the planet pointed towards ice or salt deposits being responsible and since Ceres is known to have an icy mantle, ice was considered to be the likely cause. However, this theory has been recently discredited. Information made available as the Dawn spacecraft continued its orbit towards Ceres has allowed researchers to say with more accuracy what may be causing the reflective patches. Recent proposals suggest these spots are indeed caused by salt deposits. The liquid water hidden inside Ceres would have allowed these salts to grow. Then, when an asteroid collided with the planet, this solution would have been ejected from the planet’s interior and into the crater. Here the water would evaporate away leaving only the reflective salts seen in the Dawn mission images. It is debated however if liquid water still runs under the surface or whether it was only there when the salt formed in the craters tens of millions of years ago.

This is still not the end to this mystery, though! While the spots have been shown to be made from sodium carbonate, it is unknown how such a large amount of the compound could exist on Ceres. Studies recently have suggested that though Ceres has a large amount of underground ice it is not as common as originally thought. Estimates predict that no more than 35% of its substructure can be composed of it. This is a problem as usually this carbonate forms in large bodies of water. Currently the only other place it is found, aside from Earth, has been Enceladus, a moon of Saturn layered in ice. It is a mystery how a planet as small as Ceres could have enough water needed to form this salt. It is hoped that answering this question and understanding the origin of Ceres water supply will allow us to have an insight into how water formed here on Earth. Currently it is suggested that the water in the inner solar system may have originated from the Kuiper Belt, a disc of icy rocks beyond our planets, but exactly how this was transferred to Earth is a mystery. Ceres has the potential to be an intermediate step between the water on Earth and the ice of the Kuiper Belt. Therefore research into Ceres will hopefully allow us to understand the process of how, and if, the Kuiper Belt is responsible for the formation of water on Earth.

Artist’s impression of Dawn spacecraft arriving at the dwarf planet Ceres. (Image credit: NASA/JPL-Caltech)

The Dawn mission has provided a huge amount of information about the dwarf planet Ceres and the asteroid Vesta. Many mysteries regarding Ceres and Vesta have been solved, but there are still many questions left unanswered, predominantly on the nature of Ceres’ water supply. Dawn however is continuously bringing new results, and it is expected to provide answers to this and other long standing questions about the origins of the Solar System. In particular, it is hoped that understanding Ceres will give us insight into how water formed here on Earth and the rest of the inner Solar System, an important and consequential result.

Further Reading:

The most recent images NASA has received of Ceres’ spots:

Further discussion of what the likely causes of Ceres’ spots are:

Nature article regarding levels of underground ice on Ceres

Nature article regarding salt formation and water levels on Ceres