dgfl-gh
commented
4 years ago Really appreciate the feedback! Some of the stats were definitely a swag, but others (like the number of launches required) were deliberate. Build time comes at a cost, so while I really liked the idea of this experiment requiring many launches, I thought that no one would do it, or that it would simply be annoying. But if the science output is high enough, perhaps it might be worth pursuing nonetheless. Need feedback from players here. About the power consumption: while I agree that the camera should be brought down to 10W if that's closer to its real power draw, we should make it so that running the entire satellite with tech comparable to the real one costs about 100W. All things considered, I really like these changes. Might be worth to listen to some other opinions, but they seem very reasonable so far.
marsh1832
Here's my recommendations for changes to the corona camera experiment based on my research and game play compromises.
(corona camera part) -Reduce power consumption to 10 watts -Increase dry mass to 1000kg -Decrease film capacity to 50kg (so it needs 10 launches) -Decrease experiment time to 200 days (so it needs 20 days per launch)
(sample return capsule part) -Increase avionics to 200kg
About 10 watt power consumption recommendation:
The below documents talk about vehicle 1170, also known as mission 1011, and other documents relate to this specific satellite which launched in 1964. Here is the document describing the camera and linking these descriptors:
https://www.nro.gov/Portals/65/documents/foia/CAL-Records/Cabinet4/DrawerB/4%20B%200025.pdf
Vehicle 1170 had a battery failure and the below document is the source for the battery capacity on this vehicle:
https://www.nro.gov/Portals/65/documents/foia/CAL-Records/Cabinet3/DrawerB/3%20B%200024.pdf
It describes the satellite being equipped with three 11,250 watt-hour batteries. Based on the original part's power consumption of 100 watts, that leads to a battery time of 14 days, which is actually pretty realistic as at the end of the program the satellites lasted 20 days as seen by this document:
https://www.nro.gov/Portals/65/documents/foia/CAL-Records/Cabinet2/DrawerA/2%20A%200071.pdf
(Although this was the maximum operational time, I think most satellites completed their mission in mere days as opposed to weeks.)
It is my opinion that the entire satellite probably did use about 100 watts, but it's not the camera using this power, instead the avionics and stabilization hardware, as seen in this document:
https://www.nro.gov/Portals/65/documents/foia/CAL-Records/Cabinet2/DrawerE/2%20E%200011.pdf
It says there is enough power for 24 hours but not 48, and that "considerable power" is required for passive orbits where the camera is not operating. This leads me to believe the camera is a minor power draw. When you consider the power draw of other in game components of appropriate tech levels (avionics, comms, ect) I think an accurate estimate for the average power draw for the camera as 10 watts, as the antenna and 1500kg of near earth avionics are roughly 90 watts.
However it is worth noting that how players will actually use the part, with a science core avionics, the 100 watts power draw as it is now actually does provide a good in game representation. The problem is that the part isn't being used realistically, so I think setting it to 10w will make more sense when combined with my other recommendations.
About 1000kg dry mass:
It's hard to find exact numbers, but I think vehicle 1170 had a mass of 1500kg as referenced here:
https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1964-061A
However that's the same as the payload capacity as the Thor Agena D launch vehicle, so it's hard to say what the exact mass was. However I created an analog in RP1 which had the same technology and battery capacity as mentioned above, and it was a little less than 600kg including the return capsule and everything needed. This is far too low. I can't say where the mass came from, but increasing the camera's dry mass to 1000kg will cause the satellites players create to more or less come out to be 1500kg if they create them as they were during the corona program within RP1. (near earth avionics with ~14 days of battery power)
The recommendation to increase the mass is to change how the part is utilized. Right now it's a light but power hungry return sample. I suggest making it 1000kg with 10w power drain, making the difficulty instead about getting that mass into orbit and not about powering it, which is more accurate to the real thing.
About decreasing film capacity to 50kg and decreasing experiment time to 200 days total:
Right now the part isn't being used like the real thing, that many times got it's mission done in one or two days, 20 at most as mentioned above. These recommendations are to change how the part is utilized by the players, to make it feel more like the real thing.
Decreasing the film on board to 50kg increases the number of launches to 10, and decreasing the experiment time makes it so each satellite only needs 20 days to get it's science. This will allow players to power it with period appropriate near earth avionics with only batteries, less if they "cheese" it with a science core. Because they can cheese that aspect of the camera, I instead recommend the mass be 1000kg, so the difficulty is getting 10 of these into orbit, not figuring out how to power it. Early game when the part is unlocked and the science useful, they will have difficulty cheesing the experiment by sending all 10 cameras up at once.
It's a unique experiment and this recommendation is to double down on that. This is a good choice for a player who has spare build time but either needs more science or is waiting on tech to unlock. It would be much easier science to get, so long as the player can put that mass into orbit, and was willing to spend the build time on it.
About increasing return capsule avionics to 200kg:
Right now the capsule only has a spare 34kg for the sample, even though the camera has 100kg of film. If the camera only had 50kg, increasing the capsule's spare avionics control to 84kg would allow the full sample to fit, and have a little extra left over.