8

Being off the nominal geostationary orbital velocity won't cause the satellite to fall to Earth. For a given altitude, there's one orbital velocity that yields a circular orbit. If your velocity is higher or lower, you instead get an elliptical orbit. As long as that elliptical orbit doesn't intersect the Earth or a substantial amount of the Earth's ...


8

No values for Soyuz or Dragon on wiki splashdown page, but the lake listed for the one Soyuz water landing seems to be like 20x40km. NASA shows the Soyuz landing zone as 25km wide. There is a thread on NSF where the users posted some graphs of landing accuracy, one of them showing the SpaceX COTS-1 and claiming the precision (0.8km) was much better than ...


7

There are several aspects playing a role here: first of all, every measurement has a certain random inaccuracy. Ask ten people to measure the size of an object with the best precision possible and you'll likely get ten slightly different answers. The average of those measurements is usually a much better estimate for the size than any individual measurement. ...


7

The Falcon User manual provides some information: 4.5. Mission Accuracy Data As a liquid propellant vehicle with restart capability, Falcon 9 provides the flexibility required for payload insertion into orbit with higher eccentricity and for deploying multiple payloads into slightly different orbits. Until verified by actual operations, SpaceX expects to ...


4

Actually, the accuracy of a quartz clock is sufficient, since only very short periods are measured by the GPS receiver. The following is a simple sketch on how GPS works: Three satellites A, B, C send out a signal at the same time, containing their position. So, the receiver knows the position of the satellites, but since it does not have an atomic clock, ...


3

There is nothing special about the attitude control of a CubeSat compared to any other satellite. CubeSats just have more stringent size/mass/power constraints which might limit some of your options. For the determination simple CubeSats rely on Coarse Suns Sensors (CSS) or even on the voltages from their solar panels. Magnetometers are also common, ...


3

Open sources have the Minuteman III CEP on the order of 100 m. Falcon 9 needs to be on the order of ~20 m to not miss the deck of the barge. There are big differences in targeting: The Minuteman gets its destination programmed in before launch. You usually can't send in a surveying team, so there may be some uncertainty of the target's position. The ...


2

There are a few differences. The most notable difference is the much larger distance that a Falcon 9 must go to achieve it's orbit. Also, the fact that Falcon 9 does a soft landing as compared to the fast landing required by a BM. Also, the Falcon 9 relies on GPS navigation, whereas a military system cannot be solely reliant. Lastly, these systems won't ...


1

This is indeed tricky, mainly because you're trying to do the math problem in reverse. That is, the most straightforward way to approach this is to start with a complicated model of how the big system fits together, approximate the sensitivity of the final result to the many different components of the error by taking partial derivatives, and then try to ...


1

As you said yourself, you get a system of equations from which the location can be calculated. Here the Δt consists of the difference between the time of the signal being sent at the satellite and the time of arrival. Now it is important that if we have 2 satellites next to each other in space, the Δt should be the same. This requires that the 2 clocks in ...


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