75

Are there any satellites in geosynchronous but not geostationary orbits? Yep, lots! Apparently there are various advantages to being synchronous even when oscillating wildly in position above/below the Earth's equator (up to +/- 60 degrees!) After seeing the figures below in A New Look at the GEO and Near-GEO Regimes: Operations, Disposals,and Debris (...


66

The term for orbits in our solar system around the Sun is Heliocentric. Closed Heliocentric Orbit The solar observation probe Ulysses is the furthest artificial satellite around the sun. It's in a highly inclined, elliptical orbit ranging from 1.35 Astronomical Units (AU) to 5.4 AU. It was a joint project by ESA/NASA launched in 1990 and decommissioned in ...


64

Your question is based on a false assumption namely: So why didn't NASA take money from the private sector to do these later two on the behalf of corporations? NASA did take money from the private sector to do these things. The STS-5, STS-7, STS-8, STS-41-B, STS-41-D, STS-51-A, STS-51-D, STS-51-G, STS-51-I, STS-61-B, and STS-61-C Space Shuttle ...


59

The instability in orbits of our artificial satellites come from a few basic causes: Atmospheric drag and solar wind effects The Earth isn't a perfect uniform sphere but is slightly lumpy, which means its gravitational field isn't uniform Other massive objects in the solar system perturb their orbits with their gravity So let's consider them one by one. ...


57

Yes, it really happened. It took place at the Lockheed Martin Space Systems factory in Sunnyvale, California. As the team was turning the satellite into a horizontal position, they found out that the twenty-four bolts that were supposed to hold it in place had been removed by a technician - and the action was never documented. According to NASA: The ...


46

LAGEOS satellites This has, in a way, already been done, with the Laser Geodynamics Satellite (LAGEOS) satellites. LAGEOS satellites, (the second of which was launched from the shuttle on mission STS-52), have a projected orbital lifetime of over 8 million years. They are in a very stable medium Earth orbit. They are completely passive, but are ...


45

Astronautical engineer here, welcome to the small satellite community! Firstly, it's important to recognize that the FCC tightly regulates the radio spectra available to satellites and amateur broadcasters, so before even considering how to launch your spacecraft, you should make sure your payload is legal. The FCC tables on frequency allocations can be ...


42

Essentially, this is a result of observational bias. A natural satellite will only orbit a parent for extended time periods precisely because the orbit it is in is stable †. The plain truth of the matter is that we are simply injecting satellites into unstable orbits. If you were to move natural satellites into the same orbits, they'd be unstable too. ...


41

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 ...


41

Could you fit all six into a FH fairing? If not, would a slightly larger one be enough? I can't find dimensions for GPS III sats, but this Lockheed Martin image shows how much of a Delta Medium 4-meter fairing is taken up by a single one: Looking at the dimensions of the fairing in the Payload Guide, I think the satellite is about 5m long by 2.5m wide. ...


40

(I'm interpreting the question as "what programming language was the first spacecraft software written in?", per discussion in comments above.) This will depend on your definitions of "computer" and "programming language". Almost certainly the first digital computers on spacecraft were programmed in assembly language or microcode. You can get a lot of ...


39

The way something like this typically works is that the customer, in this case the Air Force, calls the path classified, to some level. In the contract, the customer declares what parts are classified, and how such classified data should be handled. That will include the fact that any SpaceX employee that has access to the classified data must have the right ...


37

The Space Shuttle was designed to be inexpensive, but in the first launch, it was actually found to be quite a bit more expensive than it was thought. The shuttle was supposed to take only a week or two to turn around, in which case it would have been a very effective launch vehicle. Instead, the tiles ended up needing replacing after every flight, which ...


36

Is any of the following true about what is needed to achieve this: continuous change in its rotation, once and for all giving it the right spin to begin with, it happens naturally. The answer is "yes" to all three questions. If a vehicle is shaped right and is given the right rotation to start with, torques that naturally occur such as ...


36

An object as small as the Tesla Roadster will not be trackable all the way out beyond the orbit of Mars. The Tesla is too small, or space is too big, or both. The fact that the booster is still attached and that it's all pretty bright makes things a little easier, so we might be able to track it for quite a while yet (although you may have a hard time ...


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 ...


35

From this pdf (Reconsidering Sputnik: Forty Years Since the Soviet Satellite) at NASA.gov referring to Sergei Korolev, the lead rocket engineer for the Sputnik project: There were many debates on the shape of the first satellite, with most senior OKB-1 designers preferring a conical form since it fit well with the nose cone of the rocket. At a meeting ...


35

We can look at what happened when this actually occurred. The geomagnetic storm of March 1989 was caused by a Coronal Mass Ejection. Here are just a few of the many effects on satellites. One satellite lost 3 miles in altitude (not 30 km! don't believe that legend). Another began uncontrolled tumbling. GOES 7 lost communications and imagery for a time. ...


34

Yes, but it requires exceptional resolution. The GeoEye-1 satellite has 0.41 m resolution, and it has been used to count animals. Here you can see a picture it took of wildebeests: Image Credit: ITC The black and white image is the satellite image (though GeoEye-1 can do color imagery as well in 1.65 m resolution). The tiny dots peppered across the park ...


34

What would you notice first? Satellite navigation: immediately (depending on how often you use satnav) TV: immediately (depending on how often you use TV). Even if you don't use satellite TV yourself, your TV provider may receive some of its channels via satellite within a day or so: weather forecasts no longer include satellite imagery, and accuracy goes ...


32

The advantages of the blunt end first design were known well before either vehicle was launched (1958, a few years earlier for spy satellite designers). However, pointy end first is the simplest design that works. Falling objects generally want to go heavy end first, draggy end last. With a heavy heat shield on the front and a light but bulky parachute in ...


31

Voyagers are still active, and albeit they don't have the power required to run all the scientific equipment onboard and some of it stopped working by now, they still transmit telemetry data streams towards the Earth that is picked up by NASA JPL's 70-meter antenna at Goldstone, California, part of the Deep Space Network. Quoting from Wikipedia on Voyager ...


31

I spent a couple of years working in the Astrophysics and Space Physics Section of JPL. Working with the Space Physics folks taught me a lot about the solar wind and other space weather phenomena. Later on, working with Hank Garrett of JPL's Space Environments group taught me more, especially concerning effects on spacecraft. I'll start out with a ...


30

There are limits. For one, there's atmospheric effects that scatter light in visible wavelength spectrum. You might be able to penetrate clouds and haze easier in the lower end of the spectrum and towards the infrared wavelengths, and those might still be usable for facial recognition though. Another limit is aperture of optical equipment used to take ...


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 ...


28

The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km. Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, ...


27

would the photography be good enough for facial recognition? Not yet. It's not even close. Facial recognition requires 50 to 100 pixels between the eyes, or on the order of 1 millimeter resolution. To see that kind of detail from a distance of 250 kilometers using blue-green light (500 nm) would require a lens or mirror that is 125 meters in diameter. Note: ...


27

There are currently 14 known artificial satellites in Mars orbit (6 active): Mars-2, launched 1971 May 19, USSR, inactive Mars-3, launched 1971 May 28, USSR, inactive Mariner 9, launched 1971 May 30, USA, inactive Mars-5, launched 1973 July 25, USSR, inactive Viking 1, launched 1975 August 20, USA, inactive Viking 2, launched 1975 September 9, USA, inactive ...


27

The apparent source of the data (as it is linked in the source linked in the description of the author of this map) is http://apps.agi.com/SatelliteViewer/ In this animated view you can see that these are the real orbits: Satellites that currently are in the northern hemisphere show up in the southern hemisphere half a day later. As active station keeping ...


26

No spacecraft has been yet lost to the asteroid belt. In fact, we have the opposite example of missing an asteroid when it was even targeted, like was the case with MINERVA lander of the JAXA's Hayabusa deep space probe, missing the 25143 Itokawa asteroid. Why haven't we lost any spacecraft due to collision with asteroids in the asteroid belt is also pretty ...


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