Space Apps Challenge 2018

• Introduction

Humanshave always been seduced by distance and nothing is less tangiblethan sky and stars. They were also afraid of it, but now, thanks toscience progression they have gone further, trying to learn howuniverse work and trying to win their own limits going out the solarsystem. Humans are powered by a challenge against themselves tryingto overcome their limits and create new ones, trying to fulfill theircuriosity. Space has always been linked to other living entities, thepossibility of extraterrestrial creatures isn’t excluded. Humanshave always tried to look for new forms of life trying to communicatewith them.

Basingour suppositions on recent attempts like Pioneer and Voyager missionswe have found out the principal problems to take into account. Wehave looked for a way to make a possible message comprehensible toevery type of entity, supposing the presence of some essential sense,like touch and the perception of tridimensional space. We have alsothought about a new kind of propulsion completely innovative and away to make our message recognizable in the vastness of space likeradio waves at different frequencies

• Propulsion(Photonic propulsion)

Ouridea was to produce a project based not only on the message to sendto the space, but also on the type of mission and the type oflaunchers. We have decided to use photonic propulsion based on thethrust given by photons emitted by lasers.

Thistype of propulsion is a new and innovative method that includesrecent technologies. In fact lasers are being taken into account inmany recent studies. This could be a test in order to try velocitiescomparable with light speed. It would be a complete new way ofpropulsion, which is propellant free. More over the materials chosencomes from recent technologies and it would be a proof of theirresistance at high temperatures and also through time. It wouldn’ttry only the specific part of the sail but also all the parts thatlink different components.

Thrustis based on the conservation of momentum, in fact even if photons aremassless they carry momentum, in this way photons can produce thrustin the same way as matter can.

Thesystem would use many lasers with a power of 10kW each, producing atotal power of 100GW. For our purposes it’s enough a total power of100MW.

Inthis way we can find the force given to our probe, becauseF=Power/Light Velocity

F=100*106W/3*108=0,33N

Knowingthe force given by the lasers, the velocity that our probe needs toreach in order to escape from the solar system we can find out themaximum mass of the probe and the lasers lighting period.

Wehave estimated also the possible mass of the system, considering thematerials of the sail, the hardware and the “message” so the timecapsule. In total it would be, more or less, about 2kg.

So,our data are:

• Power:100MW
• F=0,33N
• Escapevelocity: 16,7 km/s=16700m/s
• Mass=2kg

Wehave considered an escape velocity of 18km/s in order to be sure toreach it.

Moreover we have considered a uniformly accelerated motion, because wecan neglect the thrust lost by the use of the laser and we want tohave just an estimation of data.

Considering:a=Δv/Δt

Considering:F=ma

Wehave: F=m Δv/Δt

Thanksto all the estimations the only remaining variable is time.

Δt=m Δv/F Including all data the result is a time of 120000s, about 33hours deferred in 5 days.

Justto make sure that this data could be applied to real uses, we havelooked the production cost of electrical energy, finding an amount of100000$, which is very reasonable considering the total prices forspace missions.

So,as a final resume:

Thecomplete probe, including the sail would be send to the space thanksto vectors used for other mission, because it would be a waste to usea single vector for a payload of only 2kg. Then, once it is in thespace, it is hit by the light array and it starts to be acceleratedfollowing the laws explained previously.

• Compositionof the project

Theidea is to create a probe composed of few different parts. The systemis composed by a central core in which most of the parts areattached. At the beginning during the launch inside the vector allthe sails are closed and they incorporate the capsule that containsthe message system. Once they are in the space and come out thevector, the sails are spread out and they start to propel the systemthanks to the light arrays. Once the right escape velocity it’sreached, so after 33 hours more or less, they detach thanks toexplosive bolts. Now, the only remaining parts are the message platemade in titanium, the communication system (antenna and audio-visualsystem) and the case in graphene, which has a curved shape, similarto a bullet. We have chosen this shape for the graphene part becauseit allows the probe to redirect small debris that could be cause ofdamage of the whole system. Its purpose is mainly defensive. Thecentral core is stuck inside the graphene part, and it has reliefs onit, which are a part of the message, and are used also to show themessage contained in the capsule. Inside the “bullet” there isall the system containing the message, which is audiovisual.

Moreover outside the capsule there will be solar panels that have the jobto store solar energy. Then an antenna is connected to the solarpanels and it sends radio waves in order to make the systemrecognizable. In fact if the probe get closer to a star, the energyincreases and so the frequency of the waves, improving the recoverypossibilities of the probe because all these changes could berecognized.

Theprobe is provided also of an internal storage connected to theaudiovisual device to hold hundreds of terabytes of data. The wholehardware is put in vacuum to prevent minor damages such as chemicalor magnetic ones.

• Materials

Oursystem is composed basically of 3 principal materials.

Thesail is made in nanotubular carbon because it is resistant to hightemperatures, impacts and it’s lightweight. The remaining centralcore of the probe, after the detachment of sails is in Titanium. Ithas be chosen for the resistance to high temperatures, but alsobecause it is malleable, allowing reliefs on it.

Thenthe case is made of graphene, another material resistant to hightemperatures and lightweight.

• Launchperiod

Inorder to try to avoid gravitational interferences made by Jupiter andMars, and also the Trojan asteroids and Hilda asteroids family wehave to choose the right launch period.

• Message

It'snow time to consider the real core of our project, the aim for whichthe previous estimate was needed. What should we store in thecapsule? Which information should we convey related to human kind?

Thescreen we proposed has been chosen in order to interact with touch inthe first place. However, if we suppose the interacting civilizationto hear and to see, then the possibility to communicate with them isexponentially increased. A problem rises at this point: who canassure us that who will find the message sees and hears exactly as wedo? For a better explanation just think of our planet: dolphins andother mammals are able to 'echolocationize' through ultrasound;several bird predators detect movement from miles of distance.Similarly, we should assume that the addressee's visible wavelengthmight extend to a shorter or a larger range compared to ours. Thesame logic can be adopted speaking of sound waves and the way theirsystem receives it.

Consequently,we might consider the way in which we communicate from a differentpoint of view. Instead of giving a series of codes or symbols inorder to let them understand us, shouldn't we focus on which tools weuse to interpret the Universe? This means to sacrifice the intelrelated to the 'translation' of our message. This thesis is evenreinforced if we think that if the civilization will be able todetect our message, it will probably have enough knowledge tocomprehend it too.

Unlikeprevious missions, what we want to convey to the founder of thecapsule is a sort of history of how we evolved, i.e. to imprint asense of change. To fulfill this, the images are to be presented in achronological order. Furthermore, we might consider presenting theartistic and the musical material at the same time.

Therewill be inserts of daily life to show our needs and our habits, plussome pictures of forests, cities, mountains, seas, everything thatreconnects to planet Earth and the environment in which we live in.

Audiovisualsystem will give explanations about:

• Instructionsto start the system
• Earthposition
• Atmosphere’schemical components
• Decimalsystem
• Unitof measure
• Artand music related to historical periods
• Informationabout humans’ daily life

• References

• https://www.nextbigfuture.com/2015/05/deep-in-dire...
• http://www.deepspace.ucsb.edu/projects/directed-en...
• http://breakthroughinitiatives.org/concept/3
• https://www.wikipedia.org/
• https://voyager.jpl.nasa.gov/
• https://www.nasa.gov/mission_pages/pioneer/index.h...
• http://www.icarusinterstellar.org/

GitHub Repository: https://github.com/Alespiels/Group_11_Hermes