# Tag Info

42

Yes, I've done it myself in my backyard in suburban Houston. During a spacewalk in ISS increment 50, an MMOD shield intended for the axial port of Node 3 was lost. It's visible in this video floating below station. It ended up reentering about six months later. A few weeks after it had been lost, I noticed that it would be visible from my house, with a ...

36

If the satellite is close to the Earth, a last bit of fuel is used to de-orbit it so that it burns up. If it is farther out, it is moved to a retirement orbit out beyond the used orbits. The last thing done after moving it to the retirement orbit is to permanently disable the communication system so that it doesn't randomly transmit stuff and put noise on ...

29

Note: This answer is based on a source from 2001. It provides a lot of background as a historical overview, but it does not take into account recent changes in the program. Please review the end of Organic Marble's answer for a fuller perspective. Initially, it began as a temporary program. In the late 1950s, the US military needed accurate and timely ...

21

A satellite that is retired ordinarily and not expected to reenter will be passivated. The aim here is to minimize the amount of energy stored in the spacecraft, ideally it will be a dead rock floating in space, far from anything it could interfere with. This includes deactivating the comms to stop interference as zeta mentions, but also emptying the tanks ...

18

The specific needs of the military may not be served by civilian weather satellites. Specifically, the DMSP started as a classified program that supported the Corona spy satellite program. Its purpose was to predict cloud cover over foreign countries so that the expendable film in the Corona satellites would not be used up taking pictures of the tops of ...

5

Are there any documented cases of satellites, planes, or space stations ruining astronomical science? A similar case that comes to mind is Project Westford. In that occasion, the backlash from the scientific community started the need for scientists to participate in the planning and evaluation of outer space projects. Sir Bernard Lovell of the Jodrell ...

5

Not to be a conspiracy theorist, but a perfectly reasonable explanation is that they are actually used for surveillance purposes. This Springer book by a former NASA and ESA expert describes it. The military weather satellites have remained separate from the civilian satellites operated by the National Oceanographic and Atmospheric Administration (NOAA), ...

4

Why? Because the US military wants to know the weather in warzones and possible future warzones (and not the USA), and that data may not be available from commercial sources. Commercial companies may be ordered by local government to restrict their data in case of war, etc.

4

To address only Astérix: Space Archaeology has a different picture and a writeup: Weighing 42 kilograms, the satellite was a distinctive striped fibreglass spinning-top shape half a meter in diameter, the black stripes to provide passive thermal control. I suspect the picture is of a replica, and this is not a primary source, but maybe it'll do until ...

3

I'm going to suggests some things you can try without using a guided image. If you really have the capability to accurately guide on a moving satellite, then you can skip much of the advice below and just use the equation. It is going to be a challenge because the satellites are moving while the stars are fixed, so you can't compare exposure values per ...

3

This is an interesting idea, and could potentially be useful for an ultra-low power application. Conventional magnetorquers require a constant supply of electrical current running through resistive copper coils in order to produce a torque using Earth's magnetic field. Since the Earth's magnetic field has a lumpy, offset and tilted dipole shape you need to ...

3

It is possible to put Pi type satellites in orbit, but not by flying your own rocket. Cubesats are a class of satellite specifically designed for this sort of thing, where larger payload owners sublet spare capacity on their launchers to smaller organizations, and get placed in orbit before or after the primary payload is delivered. Actually building the ...

3

Some good practices I'm aware of are: As you mentioned, maneuvers are simulated before they are commanded and their effect is evaluated on ground so that thruster parameters and tank filling are updated, so if anything funny is happening during maneuvers this can be identified. If propulsion is electric (which is still not so common), then thrusting is ...

3

As you want to apply Stefan-Boltzmann, I will assume that you are interested in vacuum heat and radiation dynamics. As some comments have pointed out, at 140 km, interactions with the atmosphere would be very significant or dominant. That doesn't quite look like what you are after though, so I will completely ignore the atmosphere. For a starting point, let'...

2

Geostationary is approximately 35,786 km (22,236 mi) above mean sea level. Earth's two main Van Allen Belts extend from an altitude of about 640 to 58,000 km (400 to 36,040 mi) above the surface. Changes to the Earth's magnetic field will change its Van Allen Belts, which may have an impact on geostationary satellites. Particularly if the Inner Belt ...

2

Simply yes, and this has actually been used. The most common suggestion is to use an electrical tether, basically just a length of cable played out on both sides of the satellite like two long antennas. Since the magnetic field is diminishing as you move away from the Earth, there is a potential difference across the tether. If you drive an electrical ...

2

It is very difficult, and way beyond the ability of hobby rocket science. To achieve orbit, besides large government agencies, there are very few commercial organisations able to put a payload into orbit. For amateurs, they do not get anywhere as close. For example, the European record for a student group is getting a rocket to 30km high. Although this is ...

2

I’ve seen space debris with the naked eye, and my eyesight is far from exceptional. During a supply rocket launch to the ISS, the fairings that break off the main rocket are easily visible if the conditions are right.

1

For solar astronomy, this is already being done. The STEREO spacecraft for instance are in the same orbit as Earth, but one's ahead of Earth and the other one behind Earth so they can study the Sun from different angles. For radio astronomy, interferometry is a useful tool, but if you're going to launch a radio telescope you might as well position it ...

1

Supplementary information to @Mefitico's answer: Per Wikipedia the field strength on Earth's magnetic equator (about 11 degrees from the Earth's equator and plane of GEO orbits) is about 0.3 gauss times the ratio of the Earth's radius to the GEO radius $$\left(\frac{r}{R_{GEO}}\right)^3 \approx \left(\frac{6378}{42164}\right)^3 \approx 0.0034$$ That ...

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