Why Satellites Of The Future Will Be Built To Burn PORTABLE

The >4700 launches that have been conducted across the globe since Sputnik 1 in 1957 have resulted in a steep upward trend in material mass in Earth orbit, which has exceeded 700 metric tons and shows no signs of relenting. According to computer simulations focusing on the next 200 years, over this time debris larger than approximately 20 cm across will multiply 1.5 times. Debris between 10 inches and 20 cm is set to multiply 3.2 times, and debris smaller than 10 cm will increase by a factor of 13 to 20. The risk this poses to satellites such as the ISS, which as of 2016 has had to perform 25 debris collision avoidance manoeuvres since 1999, is considerable.

The main problem with space trash is the danger it poses to working satellites and manned spacecraft. NASA frequently replaces Space Shuttle windows damaged by orbiting flakes of paint! In Figure 1 above, you see an image of an impact crater found on a Shuttle window. The crater is about 1 millimeter in size and was caused by a "space trash particle" about 100 microns in size hitting the window at a high speed. More than likely, this particle came from a solid rocket motor burn.

Because of the very great speeds at which space trash travels, small pieces between 1 and 10 centimeters in size can penetrate and damage most spacecraft. A ten-centimeter long piece of space trash can cause as much damage as twenty-five sticks of dynamite! For these reasons, NASA (together with the Department of Defense) has created a space surveillance network. Ground stations track larger pieces of space trash so that collisions with working satellites or the Space Shuttle can be avoided. Future plans include a cooperative effort among the governments of many nations to stop littering space and to possibly clean up the trash already there. Who knows, an occupation for the near future might be as a space trash collector.

There are a number of large telecommunication companies who are seeking to deploy mega-constellations of communications satellites into space in the coming decades, in an effort to increase/improve coverage and provide internet and digital service to remote areas of the world. While this is a noble goal, in some ways, adding thousands more small satellites into Low Earth Orbit will significantly increase the risk of collisions, and in the next half-century, it could even lead to a theorized catastrophe called the Kessler Syndrome. In this situation, a single collision will lead to a huge amount of additional pieces of debris, which will then strike more satellites, resulting in a devastating chain reaction. While this is believed to be impossible for a number of decades, these new proposals for mega-constellations of satellites are worrying to some theorists.

In the future, the melting of ice sheets will dominate sea level rise. Warming has already caused major changes in the ice sheets, continental masses of ice which hold a greater volume of ice than glaciers and ice caps combined. These changes are irreversible in the short term, says NASA's Eric Rignot, and it would take centuries to reverse the trail of ice retreat. In addition to polar ice, the melting of mountain glaciers, like those in the Andes and Himalayas, has caused an equal amount of sea level rise to date. However, because mountain glaciers include only one percent of all land ice, polar ice will eventually greatly surpass their contributions to global sea-level rise.

The best way to minimize future sea level rise is to cut our fossil fuel use and reduce carbon emissions. Even though some sea level rise is inevitable, we have time to reduce how much will occur. There is some debate, but according to one study every 1°C of warming will cause sea level to rise by about 2.3 meters. So the sooner we can slow our warming trend, the easier it will be for future generations to adapt.

Led by Rensselaer faculty member Riccardo Bevilacqua, the research team is challenged with developing new theories for exploiting the forces of atmospheric drag to maneuver satellites in low-Earth orbits. Atmospheric drag is present up to 500 kilometers of altitude. Using this drag to alter the trajectory of a satellite alleviates the need to burn propellant to perform such action. Decreasing the amount of required propellant will make satellites weigh less, which reduces the overall cost of launching satellites into orbit.

Accurate and complete data on fire locations and burned areas are needed to quantify trends and patterns of fire occurrence, characterize drivers of fire occurrence, projections of future fire pattern behavior, and help with assessments of fire impacts on both natural and social systems.

The urgency to clean up rocket emissions is intensifying. Last year, the space industry launched 443 satellites, more than three times as many as a decade earlier, according to the United Nations Office for Outer Space Affairs. Planned missions to the moon and Mars will increase the strain on the environment.

Expand the capacity for prediction to support wildfire response: The National Oceanic and Atmospheric Administration (NOAA) is refreshing Incident Meteorologist (IMET) equipment and increasing the overall capacity of the program. NOAA is also establishing a new Wildfire Testbed, which will expedite the deployment of new technologies for the fire weather community, allowing on-site IMETs to access and analyze information more quickly. NOAA has 86 certified IMETs to support on-scene weather forecasting at incidents across the country, with 32 newly trained IMETs to supplement deployments and increase future capacity.

Life on the planet will run into trouble well before the planet itself disintegrates. Even before the sun finishes burning hydrogen, it will have changed from its present state. The sun has been increasing its brightness by about 10% every billion years it spends burning hydrogen. Increased brightness means an increase in the amount of heat our planet receives. As the planet heats up, the water on the surface of our planet will begin to evaporate.

With a 10% increase of brightness from our star, the Earth will no longer be within the habitable zone. This will mark the beginning of the evaporation of our oceans. By the time the sun stops burning hydrogen in its core, Mars will be in the habitable zone, and the Earth will be much too hot to maintain water on its surface.

Wildfires in Canada are managed in different ways depending on how close they are to people, infrastructure, or cultural and economically valuable locations. This often means that the further north a wildfire is, the more room it has to burn without threatening Canadians. In northern Canada where population is sparse, wildfires are often left to burn, performing their natural function of regenerating these ecosystems. Even still, these remote wildfires need to be watched closely (often by aircraft survey) to ensure they are not approaching vulnerable areas. WildFireSat will allow wildfire managers to stay better informed about the status of wildfires in the North, without the need for constant costly flights.

The WildFireSat system will consist of satellites equipped with infrared sensors that will measure the energy emitted by wildfires. This energy is referred to as Fire Radiative Power (FRP). With FRP information, essential characteristics of wildfires such as fire intensity and rate of spread can be derived. It will also give us accurate data on carbon emission from wildfires.

On any given day with significant wildfire activity, hundreds of wildfires can be burning in one province or territory at the same time. With limited resources available for wildfire suppression, at times wildfires must be prioritized, with only the most critical wildfires being fought. The measurements taken by WildFireSat, together with other information such as wind direction, topography, and dryness of the area, will give wildfire managers the ability to determine which wildfires are high risk and should therefore be prioritized.

Existing satellites with infrared sensors can observe wildfires. However, for a period of several hours in the afternoon and early evening, none of the required satellite images are currently available. This long blackout period corresponds to the most critical period of wildfire activity, i.e. the late afternoon "peak burn period." During that period, higher daily temperatures, lower humidity and strong winds often result in a rapid propagation of wildfires.

In this illustration, coloured bars show the overpass times of various existing satellites that are used for wildfire management purposes: Terra (dark green), Aqua (blue), Suomi NPP (purple), Sentinel-3 (light green), Sentinel-2 (orange) and Landsat 8 (pink). WildFireSat aims to fill a crucial gap in peak burn wildfire monitoring, and to be used in conjunction with existing systems. (Credit: CFS)

WildFireSat will support research on the behaviour of wildfires and the emission of carbon, aerosols and other particles that wildfires produce. By providing a key observation of wildfire activity and FRP during the peak burn period, WildFireSat will work with existing satellites to significantly broaden our understanding of how wildfires behave and how that behaviour is changing alongside our climate. 2b1af7f3a8