Discover and read the best of Twitter Threads about #SpaceSustainability
Most recents (12)
After 6 years in orbit, we say goodbye to @CopernicusEU #Sentinel1B and thank you to teams here at ESA’s #MissionControl, who for months have worked tirelessly to troubleshoot the issue that has now resulted in end of mission 👉esa.int/Applications/O… 
As the first mission of the @CopernicusEU Programme, Sentinel-1 comprises two satellites orbiting 180 degrees apart, providing all-weather, day-and-night imagery of Earth’s surface, designed, built, launched and flown by @ESA.
The partner satellite, Sentinel-1A, remains healthy in orbit, continuing to deliver high-quality radar images for a multitude of applications.
Our focus is on fast-tracking the launch of Sentinel-1C.
Our focus is on fast-tracking the launch of Sentinel-1C.
Important and informative update from @SpaceX in response to widespread concerns about #SpaceSafety & #SpaceSustainability associated with #Starlink. Lots to unpack but worth investing time to do so (it's the Feb 22nd update entry btw) spacex.com/updates/
There's a strong focus on the collision avoidance capabilities of the #Starlink satellites rather than on the services that inform those capabilities. Ryan Hiles and co-authors presented a hugely valuable insight on this aspect at @amoscon last year amostech.com/TechnicalPaper…
The impact of #Starlink on the work of @SpaceForceDoD is explained clearly, as are the steps taken to manage the screening burden that has emerged with growing numbers of #Starlink satellites. That burden is continuing to grow (exponentially by my estimates)
Here's a thread containing the slides and thoughts I shared at today's @seradata space conference. I wasn't able to invest much time to prepare the talk, so some of the slides will look familiar to those attending April's ESA #SpaceDebris conference. Some are new [1/n]
[alt text: talk title "The Space Debris Environment - Current Status and Evolution of the Risk"]
I put this slide together using data from celestrak.com. It shows the historical evolution of the orbital object population (as recorded in the public catalogue). The highlight statistic is that active spacecraft make up 20% of the current catalogue population [2/n]
Livetweeting today's @SWFoundation Summit for Space Sustainability, using the hashtag #SWFSummit21
From @WaleedCandC: When looking at #ClimateChange the space-based EO perspective provides us:
-the global scale-view of climate change
-data to inform the implications of our actions
-tools to improve our models so we can better prepare for & mitigate changes. #SWFSummit21
-the global scale-view of climate change
-data to inform the implications of our actions
-tools to improve our models so we can better prepare for & mitigate changes. #SWFSummit21
Thelma Krug, Vice-Chair of the @IPCC_CH:
Remotely sensed data reduces our uncertainties in knowing our "energy budget" & "sea level budget," as well as better predict future conditions.
Remotely sensed data boosts re-analysis, homogeneity & continuity of datasets. #SWFSummit21
Remotely sensed data reduces our uncertainties in knowing our "energy budget" & "sea level budget," as well as better predict future conditions.
Remotely sensed data boosts re-analysis, homogeneity & continuity of datasets. #SWFSummit21
I think the #KesslerSyndrome is too often presented as a tipping point or a threshold we have yet to cross, so I wanted to use some aspects of my paper at the 8th European Conference on #SpaceDebris to explain why I think that is wrong [1/n]
The starting point of my thinking was to look at how natural populations grow. The simple exponential model is a standard model that describes the growth of a single population [2/n]
If we know the initial number of individuals in the population N(0) then this model allows us to estimate the number of individuals at any future time t. Here, r is the intrinsic rate of natural increase, which depends on the birth rate, b, and death rate, d [3/n]
Another thread about sat collision probability 🛰️💥🛰️
This time let's talk about regulations, as the FCC has just solicited input about how to regulate collision risk
As we know, risk can be computed as = 1-(1-Pc)^N
where Pc = each sat's collision probability and N = # of sats
This time let's talk about regulations, as the FCC has just solicited input about how to regulate collision risk
As we know, risk can be computed as = 1-(1-Pc)^N
where Pc = each sat's collision probability and N = # of sats
Now, you don't have to be a math expert to know which variable is most important in that equation. Yep, the exponent!
Say you've been offered X^Y dollars, where each variable is between 1-9 and you get to choose one of them. You'd choose Y every time! Who cares what X is? 💵💰💵
Say you've been offered X^Y dollars, where each variable is between 1-9 and you get to choose one of them. You'd choose Y every time! Who cares what X is? 💵💰💵
Surprisingly, the FCC has asked if they should regulate risk by only limiting Pc, or if they should also take into consideration the N part of the equation.
Isn't the math obvious? Why would anyone ignore the most important part of the equation?
Well, it makes it hard to comply
Isn't the math obvious? Why would anyone ignore the most important part of the equation?
Well, it makes it hard to comply
Here is a thread-based version of my talk at the @AeroSociety conference on 'Safeguarding Earth's Space Environment' that I hope gets some key points across about modelling #spacedebris & how it can help to identify the data we need to understand #SpaceSustainability (1/n)
Caveat: I use images as metaphors, to help with understanding of key concepts, so my slides have no words in them. (2/n)
Our models have two distinct roles: PREDICTION and UNDERSTANDING. Understanding can help us to design better models and gather more relevant data. Both of these roles are important in relation to #SST, #SpaceSafety and #SpaceSustainability (3/n)
Excellent piece by @moribajah that highlights some of the key challenges to #SpaceSustainability & #spacedebris mitigation.
For many aspects of spaceflight we can test (verify) compliance with a set of requirements before the spacecraft is launched. Will the thermal control system work? Will the solar arrays deploy? For compliance with #spacedebris rules/requirements we have to wait until after launch
We don't yet have the systems or the data needed to do this accurately or consistently across near-Earth space, and we don't yet have the understanding to do this fairly, in a way that encourages compliance without creating obstacles to sustainable development. Work still to do.
For a recent assignment on #spacedebris, I asked undergraduate & postgraduate students to evaluate the benefits & risks of a LEO (NGSO) constellation & to say whether approving a license application was merited. Here's a thread about what they said:
Of the 38 students participating, 58% thought that approving such a licence application was merited, 24% thought more analysis was needed & 18% thought that denying the license application was the correct action.
Some of the positive points identified wrt NGSO proposals were:
1. Providing internet access to remote regions & those lacking terrestrial infrastructure.
2. Meeting or exceeding expectations wrt #spacedebris mitigation guidelines.
...
1. Providing internet access to remote regions & those lacking terrestrial infrastructure.
2. Meeting or exceeding expectations wrt #spacedebris mitigation guidelines.
...
Just a few more days until the first International Orbital Debris Conference in Sugar Land, TX. Colleagues from @unisouthampton will be there to share their work on collision prediction methods, understanding light curves, and implications of changes in the upper atmosphere
@unisouthampton I'll also be in TX to share some recent work on 'mega-constellations' and what I learned about #spacedebris and #spacesustainability when I pushed our model to its limits
@unisouthampton [Some of the findings will begin to emerge tomorrow, I think]
A misconception about #spacedebris mitigation, is that the hazard is removed if a spacecraft follows the so-called "25-year rule." Leaving satellites in orbit, even for a short time, exposes them to risk. We need to start thinking about "leaving no trace" (see tweets by @nmpanek)
In a future where our space activity sees a step change over what we have seen in the past, leaving no trace is probably the only way to achieve #spacesustainability
We are starting to see unintended consequences coming from our best #spacedebris countermeasures; consequences that undermine efforts to address the problem. Switching to a "leave no trace" approach will help to avoid those issues.
I'm thinking about the challenges involved in developing a single metric of #spacesustainability or #spacedebris. A key issue is that the combination of different factors will largely be subjective (e.g is lifetime more important than mass?)
Then whomever decides how to achieve this combination will potentially influence the usefulness, the outcomes of its use, and perhaps the future of our space environment. So, who do you trust to make this decision? Should satellite operators be included?
However it is approached, the subjectivity will probably divide opinion
