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40

Removing debris costs money. Even with many words like "efficient", "low-cost", and so forth, a system capable of removing a significant amount of space debris still involves a budget requirement containing a large number of digits. For other space programs, the motivation for the large sums of money spent is a gain of some sort. Scientific data, military ...


20

Movies are misleading. Space is enormous, and almost entirely empty. Even our ”asteroid belt” is mostly empty space; we have flown several missions straight through the belt to the planets beyond without hitting anything. Low Earth orbit has collected quite a bit of space junk over the years, but even so, interplanetary probes spend only a very short time ...


13

Let's talk about the major materials that made up the Venera landers. https://space.stackexchange.com/a/9965/25 has a great summary of what the landers were made of, they are composed of include Titanium, gold, fiberglass, KG-25 an high-temperature polyurethane foam, and PTKV-260. There are a bunch of other materials, likely including some glass and other ...


7

LeoLabs tweet: We are monitoring a very high risk conjunction between two large defunct objects in LEO. Multiple data points show miss distance <25m and Pc between 1% and 20%. Combined mass of both objects is ~2,800kg. Object 1: 19826 Object 2: 36123 TCA: Oct 16 00:56UTC Event altitude: 991km From https://www.n2yo.com/ COSMOS 2004: 1 19826U 89017A ...


7

In this supplementary answer I've crudely processed all TLEs for Vanguard 1 and plotted the trends. I used the mean motion (revs/day) to get a period, divided by 0.9975 (estimating from this answer) to undo the effects of $J_2$, then used $a^3=GM (T/2 \pi)^2$ to estimate a semimajor axis, periapsis and apoapsis based on the TLE's eccentricity value. This is ...


4

The literature seems to indicate the answer is yes. There's some existing research on ejecta relative to other asteroids, but because of Bennu's irregular shape and small size those findings aren't as easily extended to the case you're interested in, so I'll focus only on Bennu-specific studies. According to McMahon et. al. in "Dynamical Evolution of ...


4

In general, it is impossible to know for sure, but we can do some detective work. My two go to web sites: https://www.space-track.org -- Catalog of all space objects kept by USAF/JSPOC https://planet4589.org -- Jonathan McDowell's amazing catalog of all things space AS you point out 2010-028* is the international designator for all the objects related to ...


4

It's a valid question. The Starlinks would require larger tanks but we're still only talking about a few percent of their 227 kg mass because they use high solar-electric propulsion rather than conventional rockets. I estimated about 2.3 kg of liquid krypton for the lower orbiting Starlink satellites in this answer. That included orbit raising from 445 to ...


4

During an interview with "the Angry Astronaut", Dynetics HLS Payload Manager Kathy Laurini suggested that the drop tanks could be salvaged and incorporated into a fuel tank farm. This suggests the tanks are dropped at a very low altitude just before touchdown, otherwise the impact would destroy them.


4

https://en.wikipedia.org/wiki/Collision_avoidance_(spacecraft) mentions this: Launch windows Collision avoidance is a concern during spaceflight launch windows. Typically, a Collision On Launch Assessment (COLA) needs to be performed and approved before launching a satellite. A launch window is said to have a COLA blackout period during ...


4

You are mixing some topics. The TLE Format is not running out numbers (directly), the 5-digit NORAD ID is and the TLE-Format is not allowing more than 5 digits in the Satellite catalog number field (columns 3-7). NORAD / USSF are planning to change their designator to a 9 digit number (allowing up to 999 999 999 designated objects), because more than 99 999 ...


4

They are not yet a thing, but are still being worked on. The system will launch on the Electron rocket. The cost isn't known, but it will be launched on an Electron rocket, costing \$6 million, and likely at least the same for the spacecraft. Let's just call it \$20 million total. One big question is how many shows can it generate per satellite. Let's go ...


3

There is no economy here. The local residents' profit is that they do not buy materials and finished products, such as boats, sleigh. Because they live in extremely remote places and transport costs make such things significantly more expensive than they cost in cities. An example of this is the documentary series "Happy People". Episode "...


3

This comment is too long to fit as a comment, so I'll write it as a partial answer. Was this really as close as call as they make it out to be if it fell just off the west coast of Africa? Definitions of "just missed" and "close call" are subjective, but we can think about the sensitivity of the final state to the initial state. A ...


3

Because it's using Earth's magnetic field to create drag. It's one of several passive deorbiting systems. An electromagnetic tether uses a conductive tether to generate an electromagnetic force as the tether system moves relative to Earth’s magnetic field. NASA: State of the Art of Small Spacecraft Technology, 12. Passive Deorbit Systems In-Space ...


3

Well I actually came here because I had a very similar question. But I have had a few thoughts about it and this is my answer to the question "What is the critical satellite density to cause a severe Kessler syndrome?". It is not complete, not the direct answer to your question and not necessarily correct. So if you want to determine the satellite ...


3

The answer is that the Hayabusa-2 was 4.61 km from the SCI when it detonated. The link provides a mission status briefing from JAXA which describes the entire sequence of events, including positions. Slide 10 has the relevant mission data laid out on a grid. http://www.hayabusa2.jaxa.jp/en/enjoy/material/press/Hayabusa2_Press20190411_ver10_en.pdf Before the ...


2

In October I attended a talk on blockchain applications in the space industry at a conference. The speaker (someone from PWC Space Practice office) listed a couple possible use-cases. These are more extensively described in this white paper. Note that this is just a list of things the speaker talked about and I'm not expressing any opinion on the value of ...


1

What exactly is your goal? Are you looking for errors in the TLE data, or are you trusting them to be correct and using their distribution to tell you what sorts of orbits are unusual for satellites to be in? Trying to spot errors just by statistical means is inherently murky; if you want to do that for real, you need better orbit data to compare against. ...


1

How do they monitor the movement of these[...] Sensors a.k.a. radar (for LEO): the US Air - now Space - Force dedicated old Ballistic Missiles Defence Systems for Space Survaillance. This radars are tracking as much objects passing above as possible. [...] to avoid so many possible risks of collisions [...] To make it a bit simple: this measurements are ...


1

Was able to figure out how to achieve this. Alpha acts like a probability of which normal distribution to use. As such use a array to switch the values depending on the probability as follows: # Creates a array of tuples, where the first value is mean 1, and the second is mean 2 mean_preSwitch = np.array(mean_AM(lambda_c)) # Generate a uniform distribution ...


1

Space debris speeds depend on these variables: the original orbit of the object that created the debris the amount of energy in the event that created the debris (explosion, collision, breakup, accidental release) the weight of the debris (given the same amount of input energy, lighter fragments will be launched at higher speeds)


1

No at least not in the foreseeable future. As is pointed out in the comment the time spent in the LEO shell is many orders of magnitude higher for a satellite that is designed to stay in LEO, than one then just punching through. Hence for the density of debris in LEO to cause significant concern for passing craft would be required to be many orders of ...


1

I obtained the chart from data I logged and reverse-engineered for Hayabusa OnBoardCamera and LIDAR; unfortunately telemetries feed broke right after SCI operation, for several days: Planned timeline: Interactive chart: http://programmi.hostingerapp.com/hayabusa2/simulator/haya2-dates-5000.html Schedule was: 04/05 01:44 - 500 meters - Estimated target ...


1

This additional answer is just to show the effect of the solar activity on the decay rate. The graphs were obtained from 15279 TLEs downloaded from https://celestrak.com/NORAD/archives/request.php processed with the CSpOC's SGP4 library freely downloadable from www.space-track.org. The following graph shows the mean radius vector and the mean air density (...


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