72

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 (...


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, ...


26

Kepler has a parabolic dish antenna fixed to its body. There are many possible designs of transmitting devices. For spacecraft, parabolic dish antennas are preferred, because they have the least attenuation for radio waves with distance. But dish antennas must be pointed to the receiver. The Kepler telescope was over-budget for a Discovery-class mission, ...


25

The ISS solar array masts are launched collapsed in canisters, and run through a deployer mechanism to erect them as a long straight object. I see no technical reason why a much longer mast couldn't use this system. For details see this question and answer: How do the booms on ISS (and other spacecraft) extend and retract?


23

Long rigid structure can be transported as raw material for fabrication in space, in the same way that continuous rain gutters are made. In the pictures below, you can see a machine that creates the rigid rain gutter from a compact roll of sheet metal. The method is provides for compact transportation, only limited by the compacted size and weight of the ...


21

Rockets (even old designs) are capable of delivering a nuclear weapon anywhere on Earth. Governments don't want this technology to fall into the wrong hands. Publishing a design takes a lot of effort. The complete design for a rocket easily exceeds a million drawings and hundreds of thousands of pages of supporting documents. For an old rocket, all of that ...


20

Storage just means that they're launched and still in geosynchronous orbit but not actively used. You can see the status of the Tracking and Data Relay Satellite (TDRS) Fleet on this NASA graphic: Of the eleven TDRS satellites successfully launched into space, nine are still functioning and two (TDRS-1 and TDRS-4) are not. The two non-functional ...


20

Solar panel technology seems to have caught up with power requirements on the satellite. Since price of components is really no object when building a system like this, super expensive panels with efficiency ratings of up to 40% can be used. The trick to engineering something properly is using just the right amount of materials, as the old maxim goes "Any ...


17

Certainly. For instance, the two LAGEOS satellites, orbiting at 5,900 km, are expected to remain in orbit for eight million years or more. Those satellites were made especially dense, which will also tend to slow orbital decay. But less compact satellites in high orbits should do fine for long periods as well.


17

Best way to do this could be to research, develop and send a "3D tube printer satellite" to low Earth orbit, and feed it with whatever material in liquid, powder or filament form, which will not require any special attachement or design modification to existing rockets, since it can fill any shape of a given volume. For instance one 0.5 km long tube, 10 cm ...


17

Lagrange points as I understand it are points in space between 2 objects where the gravitational pull between them is effectively equal. A quick check of Wikipedia's Lagrangian point or any article will show that only one of the five Lagrange points are "between (the) two objects". The pulls are not equal, they balance in such a way as to allow for an orbit ...


15

MarCO's primary mission isn't actually to transmit data from InSight during its entry period. That's a non-essentially function that can be done by other spacecraft, if needed. Instead, the main part of the MarCO mission is determining the functionality of cubesats during deep space missions. We've never before sent such small spacecraft this far from Earth, ...


14

Could a slower or smaller rocket take advantage of lift if all the stages had wings? Wings on the first stage can be useful; the Pegasus air-launched rocket has wings on its first stage that provide some lift. In most cases wings aren't worth using on orbital launchers; they add drag and weight that usually isn't compensated for by lift. Wings on upper ...


12

This largely depends on purpose/application, but if you want it just to "be in orbit" then the answer is "not very precise at all.". Or quantifying better, the periapsis speed must be between the speed of circular orbit and escape speed which is $\sqrt{2}$ of that - so about 40% of "slop". Of course satellites aren't of much use if you can't communicate ...


11

A thin pole .5 km long is easier said than done. A scaffolding pole (4 m long, 4 cm diameter) may seem rigid, but link a few end-to-end and the resulting pole will be flexible. If you attach it to the outside of a rocket, it'll start wobbling under the aerodynamic loads. You can combat this by making the diameter larger, but to support a pole 500 m long ...


11

Not an answer, but comments can't have pictures. After the primary mission of supporting the InSight landing, one of the MarCO sats did snap a nice picture of Mars while departing:


10

I wrote code that flew on 3 spacecraft that went to Mars, one to the Moon, one to a comet and back, and a few Earth-orbiting satellites, the last of which was about 10 yrs ago. All of them used C. It's not the only language out there, of course, but it's popular because the perception is that code can be made smaller and faster using C, without the overhead ...


10

Neither the MarCO satellites nor InSight itself had the ability to enter Martian orbit - the interplanetary approach to Mars is quite fast, and it takes a lot of fuel to slow down enough for Mars to capture a probe. InSight itself used Mars's atmosphere to slow itself down, but the MarCO satellites had neither heat shields nor significant maneuvering ...


9

A 500m pole would have a very significant effect on the rocket aerodynamics because it will disturb the airflow above the rocket; increasing the drag. Especially once supersonic. The drag would be monstrous, and it would need to survive the strong forces of Max Q, and the high Gs of launch. This leaves us with a somewhat inextricable problem, and out good ...


9

I am going to answer the question as asked, ignoring the comments. The system in question is a sphere pierced by a rod. Some internal mechanism acts to move the two parts relative to each other. Let's look at the two limiting cases - massless rod and massless sphere. For the massless sphere, the c.g. (red star) is in the center of the rod, it stays where ...


8

Look at the very page you're linking in your question: TSRS-C is retired. When they quit using it they boosted it 300 miles farther out so it wouldn't be a navigation hazard to other synchronous satellites. It's called a storage orbit, hence the satellite is in storage.


8

This is a great question! tl;dr From a circular orbit, a little more or less velocity just makes your orbit slightly elliptical. If your orbit happened to be very close to the Earth's surface (LEO or low Earth orbit, like the ISS), then a little less velocity (at a given height) would put you deep into the atmosphere and you'd burn up. But that's not ...


8

Both MarCO cubesats are flying by Mars -- not in orbit. Furthermore, during their radio coverage of InSight's entry/descent/landing, their solar arrays are pointed away from the sun, towards Mars. They are on battery power, and will eventually stop transmitting when the batteries die. Then they will continue passively around the sun.


7

Solar array designs vary a lot and need to be tailored to the mission they will power, so the specific power ratings (power per mass of the array—higher is better!) vary a lot as well. In addition to Boeing/Spectrolab mentioned by @called2voyage there are several other manufacturers of space-qualified solar arrays, such as Northrup-Grumman, Lockheed-Martin/...


7

Why would Kepler rotate towards Earth instead having an antenna always directed to Earth? There was no need to always have an antenna pointed directly at the Earth because communication with the Earth was infrequent, less than eight hours per month. There are a lot more deep space assets than there are receivers to communicate with those assets. The ...


7

Based on your question, I'm assuming that you are in the United States. If that's right, you need to get licenses from NOAA if you are engaged in remote sensing (basically if you have a camera on-board), and you need to get a license from the FCC to transmit/receive radio signals. Assuming you aren't doing the launch yourself, that's all you need to do. ...


7

MRO uses the Electra software-defined radio: Electra is a telecommunications package that acts as a communications relay and navigation aid for Mars spacecraft. Toward the end of the primary science phase, other Mars missions launched in 2007 and beyond will begin to arrive. Mars Reconnaissance Orbiter will use its Electra UHF radio to support any ...


7

Though it seems noöne has spun an entire rocket stage to slow it, something similar has been tried. The long-defunct Rotary Rocket company was developing the Roton™ reüsable single-stage-to-orbit launcher that would use helicopter-like blades to slow and land. A bit more info on it can be found on Wikipedia. Alan Radecki via Wikimedia Commons, GFDL / CC ...


7

You are correct in your understanding, Once it reaches the vicinity of the South Pole, specifically the most southern point in its orbit it will start going north. The reason they said north to south is to differentiate it from the orbits going west to east (which by the way stay west to east). This is also very neatly demonstrated by the satellite's ...


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