I honestly didn't think China would succeed with that satellite warfare demonstration. The fact that they were willing to try it was bad enough. The fat that they succeeded was doible plus bad.
The thread for space cadets!
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hobbsyoyo
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Yeah I'm talking about life on Earth being wiped out by the Sun eventually. Or an asteroid. Or Yellowstone going off. Take your pick. Yes, it's arrogant to think humans can help prevent a complete wipeout of life but we have billions of years to figure it out.
The top image - are those solar panels? Are we looking up at the underside of the cubesat? What are the 6 panels / windows on the large face of the body?
hobbsyoyo
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Details are on this webpage.
The blue wings are solar panels, the gray boxes are GPS antennas. This is a weather satellite that sounds the atmosphere by measuring GPS signals that pass through it on the Earth limb.
We recently achieved a concept called 'responsive space' with the last two launches in the constellation - we were returning payload data to NOAA within 24 hours of launch. This made my job of flying them during commissioning easy which is all you can ask for from a job. The satellites are about the size of a shoebox and provide more accurate measurements than all of NOAA's billion dollar satellites. Granted, these only do GPS occultations (the name of the technique) while the NOAA birds do a ton of other stuff. But at this one thing, we are literally the best in the world.
At a meta level - there is a lot of concern right now about the potential for space debris and interferences from swarms of small constellations like OPI here as they replace larger and less numerous birds. However, from a purely cost perspective, CubeSats win by orders of magnitude and are quickly proving their capabilities at specific tasks. It's fair to say they are less versatile but when you can launch 10 satellites to do 10 things cheaper than you can launch 1 satellite to do 3 things, the trade is often attractive.
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Thorgalaeg
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Miniaturization has finally arrived to space too. Maybe it is more cost effective that way but I miss my boombox.
Details are on this webpage.
The blue wings are solar panels, the gray boxes are GPS antennas. This is a weather satellite that sounds the atmosphere by measuring GPS signals that pass through it on the Earth limb.
We recently achieved a concept called 'responsive space' with the last two launches in the constellation - we were returning payload data to NOAA within 24 hours of launch. This made my job of flying them during commissioning easy which is all you can ask for from a job. The satellites are about the size of a shoebox and provide more accurate measurements than all of NOAA's billion dollar satellites. Granted, these only do GPS occultations (the name of the technique) while the NOAA birds do a ton of other stuff. But at this one thing, we are literally the best in the world.
At a meta level - there is a lot of concern right now about the potential for space debris and interferences from swarms of small constellations like OPI here as they replace larger and less numerous birds. However, from a purely cost perspective, CubeSats win by orders of magnitude and are quickly proving their capabilities at specific tasks. It's fair to say they are less versatile but when you can launch 10 satellites to do 10 things cheaper than you can launch 1 satellite to do 3 things, the trade is often attractive.
This is really interesting! I do really worry about the debris aspect of things - not sure if my concerns are well-calibrated with reality though. I believe I heard that there's a Japanese mission that will start to test the feasibility of helping junk drop orbit? Not sure if I'm remembering right.
reading your link, this stood out:
If I understand correctly, doesn't this mean that the CICERO-6 is in a reverse (retrograde?) orbit? I take sun-synchronous to mean that it holds position relative to the sun, which would mean that from the Earth the satellite appears stationary relative to the sun - so its proper motion is east to west, not west to east like any other satellite I've read about... surely I must be getting something wrong here, as a retrograde orbit would take a ton more fuel to achieve, which would then cost a ton more, and so on...
Edit: wait, inclination of 97º?... how does that work. Doesn't that mean it's going back up and over the pole, but reverso? Wouldn't 90º be a straight up polar orbit? I need to start getting back into KSP, obviously.
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hobbsyoyo
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You remembered it right and I believe it was talked about here as well. It's a dumb idea. I mean an on-demand meteor shower is cool but not worth the risk to other objects in LEO should something go wrong. If the satellite were to say, be turned in the wrong direction when it released the meteors, it could kick them into a higher orbit where they stay up for a long time.
90 degree orbits go straight up and down over the poles. 97 degree orbits go over the poles too but are slightly tilted backwards such that they are going the opposite direction of Earth's spin.
Not sure what it looks like from the ground, but for the satellite, sun-synchronous means the satellite will revisit the same spot on earth at the same time of (local) day, every day. This ensures static lighting conditions from the satellite's perspective which is super important if you are taking images of the ground. So this orbit is super useful for observation satellites of various flavors for that reason. OPI is not an observation satellite and gains no benefit for this.
CubeSats are almost always rideshares, so they end up going wherever the launch they bought takes them. Even though OPI wouldn't benefit from the static lighting conditions on the ground from this orbit, it does gain other advantages:
- A polar orbit goes over the entire surface of the Earth as the Earth rotates under the satellite over the course of a few days.
- A polar orbit goes over the poles on every single orbit - this means you can put a ground station at either pole and contact the satellite basically every orbit. Satellites in other orbits have 'blackout' periods where they do not pass over a ground station for hours at a time - unless you pay for dozens of ground stations scattered all over the Earth.
There are other special polar orbits like a sunrider which uses the same buldge-dragging effect to stay on the terminator (cutoff between day and night) continuously which means it can:
- Have continuous solar power
- Always face instruments into sunlit portions of the Earth
- Always face instruments into the night side of the Earth
90 degree orbits are not really special compared to sun-sync. Most launches do not go to that inclination and will instead go to sun-sync. Rocket Lab has been going to that orbit and to be completely honest I'm not really sure why they go to that exact orbit except as a compromise between all of their CubeSat payloads. CubeSat manufacturers and operators tend to favor polar orbits because it limits the amount of ground stations they have to pay for to talk to their satellite. If RL launched to a particular sun-sync for one satellite on their launch, that might be unfavorable to other satellites on the launch. If they go to a sunrider orbit, that may be too hot for some of the satellites on the launch. So 90 degrees is basically the compromise so everyone can to a polar orbit but no one is especially disadvantaged by it.
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Lexicus
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Wouldn't it be easier to have relay ships instead of ground stations?
hobbsyoyo
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Polar orbits are so useful that countries often maintain second launch pads to go to those orbits. India is lucky in that its location allows it to go to either an equatorial launch or a polar launch without flying over too much land but this isn't the case with other countries. In the US, flights out of Florida can go to equatorial orbits but if they went polar, they'd fly over Caribbean islands so the US doesn't do that (any more). Instead, polar orbits from the US are launched out of either California or Alaska (almost entirely California) - two states which allow you to fly over water southward for polar orbits but over land to the east for equatorial launches (which are not launched from those states). For similar reasons, Russia launches out of Baikonaur for equatorial launches (where they fly over mostly uninhabited areas of Kazakhstan) or Plesetsk for polar orbits.
New Zealand's launch pad is only used for polar orbits but that's as much to do with the Electron's low performance as it does with location of New Zealand. NZ is a bit south to be going to equatorial orbits but the Electron would have to spend a lot of fuel to get to it. Instead, Rocket Lab is building a second launch pad at Wallops Island, Virginia to go to equatorial orbits as the performance hit at that location is much smaller.
New Zealand's launch pad is only used for polar orbits but that's as much to do with the Electron's low performance as it does with location of New Zealand. NZ is a bit south to be going to equatorial orbits but the Electron would have to spend a lot of fuel to get to it. Instead, Rocket Lab is building a second launch pad at Wallops Island, Virginia to go to equatorial orbits as the performance hit at that location is much smaller.
hobbsyoyo
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Typically, operating or leasing space on a ship is far more expensive than a ground-based station due to the cost of fuel and the additional logistics involved. For example, a ship will have to transmit the signals back to land somehow (probably through other satellites) which dramatically increases the cost all by itself. And fuel isn't cheap either.
To be clear, it has been done. Russia in particular used a few ships for satellite telemetry and command but it was as much a geopolitical decision to use boats instead of ground stations as it was a technical one. And for a superpower, cost is usually a secondary concern but for small companies like mine, boats are very expensive.
Edit:
Also, usually one or two contacts per orbit is enough to fly a satellite properly so you don't need continuous ground station coverage. At the same time, you don't want to go 10 hours without talking to the satellite either, so polar stations and orbits are very handy in this regard.
Manned missions are different which is why NASA built a large constellation of satellites (TDRSS) that can talk to manned spacecraft at all points during flight and relay communications to fixed ground stations. This was also why Russia used to use so many ships for relaying communications though as their space budget has collapsed, these vessels have been decommissioned or unused in this role.
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Thorgalaeg
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Watch out! They are goin to burn! 
BenitoChavez
What business is it of yours?
I saw the lunar eclipse tonight, or at least a little bit of it. It was super cold (-20C/-4F) outside so didn't stay out too long. I took some photos, pretty crappy but it's the best my phone could do. It looked pretty cool in person. Sort of a dark red color.
Spoiler Crappy photo #1 :
Spoiler 'Zoomed' :
hobbsyoyo
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It is my understanding that the shuttle spent most of its time with the cockpit facing the Earth. The heat exchangers for the thermal control system were in the bay doors so they generally kept those open. Normally you would want to face the heat exchangers to deep space so they can radiate the heat into the black sky. If you do this though, you have to avoid the sun which will sweep overhead over the course of an orbit and which would overwhelm the thermal control system. Normally this would involve turning the satellite with reaction wheels but I don't think the space shuttle had them which meant they had to burn a bit of fuel for every manuever.Watch out! They are goin to burn!
Instead, they pointed the bay doors and cockpit toward the Earth. The thermal control system works less efficiently in this attitude because the Earth is warmer than deep space and won't act as well as a heat sink for the heat exchangers. This way, temperatures are stable, the sun doesn't mess anything up and the shuttle doesn't have to burn fuel.
That's my long winded way of saying they really are going to burn up if they stay like that too long!
Berzerker
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https://phys.org/news/2019-01-mystery-orbits-outermost-solar-planet.html
Planet 9 news... It may not exist
short version, study says "if" there is more mass - 5-10 earth masses - out in the Kuiper Belt that could explain the orbits of minor planets indicating a 9th planet
Planet 9 news... It may not exist
short version, study says "if" there is more mass - 5-10 earth masses - out in the Kuiper Belt that could explain the orbits of minor planets indicating a 9th planet
There's some hubbub going around* that the POTUS was going to give NASA 'unlimited funding' if they could get a manned mission to Mars in his first term.
Not only would such a thing be frankly impossible (we might be able to squeeze out a Lunar mission. If we were cartoon level villains, we probably could shoot a person to Mars in four years, but it would basically be a man stuck in a capsule or two with supplies on a flyby. At best), but the POTUS does not have the power of purse; it is a unenforceable promise. At best, Congress might had allotted some extra few billion every year, out of his political goodwill, somehow.
Should NASA had tried to string him along, even in a compromise, or was it good that it was DOA?
*Read: R/Space locked post.
Not only would such a thing be frankly impossible (we might be able to squeeze out a Lunar mission. If we were cartoon level villains, we probably could shoot a person to Mars in four years, but it would basically be a man stuck in a capsule or two with supplies on a flyby. At best), but the POTUS does not have the power of purse; it is a unenforceable promise. At best, Congress might had allotted some extra few billion every year, out of his political goodwill, somehow.
Should NASA had tried to string him along, even in a compromise, or was it good that it was DOA?
*Read: R/Space locked post.
Berzerker
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I dont know, look what happened the last time mankind tried to reach Heaven to be with God
hobbsyoyo
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NASA was right to turn down the offer because it would have entailed major risks for the astronauts.
But they (and their army of contractors) could have pulled it off.
