How does Space Tech fit alongside the SDGs?
Tourism, in the Earthly sense, is known to have both upsides and downsides for the communities and environment it touches. However, space tourism sits outside, nay orbits, these norms.
Watching the recent private space launches, I started wondering how much damage is being done to the climate by this billionaire one-up-manship?
Researching how much CO2 a single SpaceX launch emits, I found answers that coalesced around 340-ish passengers flying across the Atlantic on a commercial airline. In hard numbers it’s about 336 metric tones of CO2 per launch (and remember, it’s only on the way up, because most use gravity on the way down).
Another interesting article argued that since most of the people currently able to jaunt into space are billionaires, we should compare the emissions to what they’d spend in their private jets (not commercial), and actually the private jets are much more of a concern. That's a pretty interesting point, given the focus private jets have had during COP26...
Forbes calculated that 118 private jets were used by leaders attending COP26 and that would equate to roughly 1,000 tons of CO2. Putting that another way, that’s about three SpaceX launches or 2.5 million miles driven in an average car.
Looking beyond tourism
Of course, tourism is just part of the picture, and most likely one that has been used to bank-roll a fair bit of financing. Another big part of the private sector space industry is focused on reducing the cost of putting things in space.
I dare say that the cost of Musk’s Starlink satellite constellations would have been considerably higher if being launched using legacy launch programmes. I would also be willing to take a gamble on saying the business cases for Starlink and SpaceX tourism are mutually beneficial, with a primary objective being to make it easier, cheaper and faster to get things into space.
But is Starlink a Tech With Purpose?
Given the current price point and wait list, I would find it hard to argue that Starlink is currently a Tech With Purpose. However, it could be I can see how it could be … one day.
As I mentioned in a previous article, universal access to connectivity is a crucial foundation to the achievement of many of the SDGs, so over time, as the price point and proposition matures, Starlink (and/or future evolutions of it) could hold the key to rural community connectivity.
Space Tech With Purpose
But if one of the visions is to make it cheaper to get things into space, then what good will that do us all down here on Earth?
It turns out, quite a lot.
Data captured from satellites are being used in many ways to help conduct scientific investigations here on the ground, inform policy making decisions, improve weather modelling, predict and monitor disasters, measure, track and hold corporations accountable to their environmental impact, understand migration, human impact and much more.
Satellites provide us with the ability to understand our planet and humanity at global scale, and as such can help identify things that we’re either simply too close to to see, or are virtually invisible to any other terrestrial method of measurement.
GRACE in Space
One such example is with the GRACE project.
GRACE (Gravity Recovery and Climate Experiment) was a twin-satellite joint project between NASA's Jet Propulsion Lab (JPL) and the German Space Agency (DLR) operated between 2002 and 2017. The objective was to measure changes in the Earth's surface mass and water distribution through the observation of changes in gravity on monthly time scales.
Example GRACE mapping outputhttp://gravis.gfz-potsdam.de/home
It all sounded a bit much to comprehend, so I picked up the phone and spoke to Professor Frank Flechtner.
As Head of Section “Global Geomonitoring and Gravity Field” in Department “Geodesy” of the German Research Centre for Geosciences in Potsdam (GFZ) and Professor for “Physical Geodesy” at the Technical University of Berlin, he has been working on GRACE since 1999 and in 2013 became the co-principal investigator - effectively heading GFZ's involvement in the joint project.
What is a geodesy dealing with?
Geodesy is the science of accurately measuring and understanding Earth's geometric shape, orientation in space, and gravitational field.
How did you become involved in the GRACE project?
I first started working on GRACE in 1999, where I was responsible for the German contributed elements of the joint project including the German Science Data System. Then in 2013, whilst becoming Head of Section “Global Geomonitoring and Gravity Field” at GFZ I became also co-principal investigator of the project.
I was fascinated about how to measure distance variations as small as a micrometer between the two satellites over distances of 220km, and soon became quite enthusiastic about derived gravitational maps, the changes between seasons and years and how it relates to climate change.
What is GRACE?
GRACE (2002-2017) as well as its successor GRACE Follow-on (realized between NASA and GFZ and launched in 2018) consists of two identical satellites, circling the Earth at an altitude of 500km. One follows the other with a distance of about 220km between each other.
As the gravity field affects the orbit of each of the two satellites slightly different the tiny variations in distance directly mirror subtle changes in gravity across the surface of our planet. The separation data along with a number of other observations such as GPS-derived positions of the satellites or non-gravitational forces caused by air drag or solar radiation are collected over one month and inverted to monthly gravity maps.
These distance variations are very small as the gravity signal of the Earth is decreasing with orbital altitude, and therefore in the order of only a few micrometers at 500km.
Who small are the changes GRACE can detect?
The GRACE and GRACE-FO twins are able to detect variations in the gravity field acceleration down to the 8th decimal place. You might remember from your school days that gravity acceleration on Earth is typically approximated as 9.807m/s² which is valid if the Earth would be a solid sphere with a certain density. Due to continuous mass variations in the hydrological cycle this approximation changes with space and time. GRACE is able to distinguish these variations in this force to a very granular level of 1 10-8, such as 9.80700021m/s² versus 9.80700028m/s².
How do you measure that?
The original GRACE mission used microwave measurement techniques to observe these distance variations with an accuracy of about 1-2 micrometers. For references, a human hair is around 20 micrometers. GRACE-FO operates a Laser Ranging Interferometer as a technology demonstrator for future gravity missions. Real data analysis showed that the laser concept improves the accuracy down to 10 nanometers.
You mentioned identifying climate change related outcomes, can you tell us more?
GRACE is about measuring the distribution of mass across the planet. So, for example, as the Greenland and Antarctica ice caps melt and the water finally dissipates across the oceans, that is a movement of mass across the planet visible in sea level rise. GRACE can determine these shifting masses, month to month, year to year and can detect climate change related signals such as changes in deep ocean currents or size and number of floods or droughts as well as groundwater extraction.
What is the output of the mission?
Essentially, the satellites collect every month huge amounts of data, starting at Level-0 raw data from the instruments up to Level-3 “ready to use” maps of the mass distribution on our planet.
The data can be found on my department's website that can be used to identify water storage across the planet, such as monthly total water storage over land areas but also ocean bottom pressure or ice melt in Greenland or Antarctica. This data is held in two archives, one in the US and another here in Germany at my department. Both are accessible to the public for free.
How often is the data refreshed and how granular is it?
The final Level-3 data on our website is updated monthly, with a delay no longer than two to three months from capture. The spatial resolution and accuracy of the data is limited by several factors, mostly due to the orbit design and related anisotropic sampling of the satellite-to-satellite tracking in North-South direction, not perfectly modelled short term mass variations in the atmosphere and oceans and errors in the measurement of non-gravitational forces, all resulting in a pixel size of about 250 km.
Future gravity missions will fly at lower altitudes and will also add an additional pair of satellites flying in an inclined orbit adding the missing East-West component. Then the high precision of the Laser Ranging Interferometer, together with improvements in measuring the non-gravitational forces, will significantly increase the spatial and temporal resolution as well as accuracy of the derived mass transport products.
How is the data being used for the good of humanity and the planet?
It is difficult to track all the use cases of the data, as it is available to scientists, governments, NGOs, enterprises, startups and individuals - they could use it in so many ways. There are, however a couple of use cases that have global impact that I can mention. Improving our understanding of the global water cycle has never been more critical. Some of the indicators used within the climate change modelling and monitoring are water availability, ice loss from polar and glacier regions or sea level - these data are derived from GRACE outputs. In combination with other satellite or model data for quantifying soil moisture, surface water, snow or run-off, GRACE derived total water storage maps are currently used to develop a prototype for a Global Gravity-based Groundwater product.
The GRACE project, and successors are ambitious, highly sensitive pieces of equipment aimed at helping us understand massive changes on our planet, that are much harder to notice down here on Earth. The satellites fly around the planet, tailing each other and measuring minuscule changes in distance between each other caused by the changes in gravitational ‘pull’ exerted on them by the changing landscape below.
As joint public missions between the US and Germany, this data is publicly available and being used for many purposes, from understanding the morphing shape of our planet, the impact of climate warming, to helping identify changes in regional water tables and flows.
If you want to access the data, simply head over to Professor Flechtner’s departmental website, here German Research Centre for Geosciences (GFZ). To find out more about Professor Flechtner, head over to his departmental profile, here.
My "aha!" moment
Of course, I had already understood that when the ice-caps melt, the water distributes back into the oceans, causing sea levels to rise. What I hadn't appreciated, is that this relates to a change in the distribution of mass across the planet, resulting in another change of the planet's gravitational fields.
Space tourism costs
Just for fun, let's look at some of the costs.
Three passengers are known to have paid $55 million each for a 10-day journey, including eight days aboard the luxurious International Space Station with SpaceX. Naturally, for that price you'd hope it would be all-inclusive, and indeed it was. The ticket includes training, launch, and the daily cost of living on the ISS. But unlike most all-inclusives, there's no mention of local beers and main-brand spirits, so I have no idea what drinks are/are not included.
So, in total, that's $165 million for 30 days of experience.
Coincidentally, 165 million (GBP, not USD) is the same amount the UK Government announced at COP26 that they would spend on helping improve gender equality in addressing climate change. The announcement allocate two tranches of money across Asia and the Pacific communities to help improve resilience climate change, prevent pollution, protect biodiversity, strengthen renewable energy and better manage waste, while also supporting female leadership, access to education, skill and finance.
Tell me what you think
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