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Questions about orbital ring math from Birch 1982 paper

I have been reading the original Paul Birch paper published in JBIS 1982. I have been using this copy found here. In particular I am wondering about generalizing the ideas, like for a different planet ...
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0answers
7 views

What if a pin size object travelling with a speed close to that of light, hits the surface of earth?

Of all possibilities I could imagine is that it would either get burnt or maybe pierce through the planet and get burnt up at the core. Could it be more catastrophic than this?
2
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0answers
31 views

Could you bounce a tennis ball off of the James Webb sunshield?

News articles keep referring to the James Webb Space Telescope's sunshield as "about the size of a tennis court", which raises the question: could it function as a tennis court? Or, more ...
7
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2answers
410 views

Has any piston machine been used on a space mission?

Inspired by question about engine lubrication in space. Piston engines are not used for propelling spacecraft, but there are some possible uses for especially Stirling engines and compressors: ...
1
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1answer
44 views

How would an SSTO adapt to various payloads?

Yet another kerbal question here. Background: I've built many SSTOs before, mainly small, light-payload or crew delivery ones (either boosted by a rocket or by itself). The reason why I've been shying ...
-3
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0answers
34 views

Why time flows slower for objects moving with speed close to speed of light? [closed]

What does it mean? I assume that time was inventioned by humans and this is only an abstract idea. But why do we see the relativistic time delation? Does it mean that quantum processes flow slower ...
4
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1answer
167 views

Which aspects of the JWST wavefront process are the most time-consuming?

NASA is currently estimating the that the upcoming wavefront process to align the JWST's mirror segments will take around three months. This description of the WFSC process paints a picture of ...
-1
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0answers
35 views

If I'm moving with speed of light but without any acceleration will I see any relativistic effects? [closed]

As the moving is relative there is no matter on which speed you are moving if there is no acceleration. We will fill it exactly the same as no moving (if other objects moves with the same speed). So, ...
-2
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1answer
31 views

Could we model spacetime and light using water and waves on water? [closed]

I like to think about spacetime as about water and light and gravitational waves is a just a waves on water in that case. Can I use this analogy? Does the water waves has a limit speed like ...
-1
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0answers
33 views

If you travel on car with the speed of light and turn on the car headlights: will it shine in gamma light instead of visible light? [closed]

If you travel on car with the speed of light and turn on the car headlights: will it shine in gamma light instead of visible light?
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0answers
28 views

On which speed the background radiation becomes dangerous for the people on space ship? [closed]

If we travel with speed close to the speed of light, the light waves becomes shorter and their energy increases (because we flight through much more light for the same time). So, even background ...
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0answers
28 views

Do photons exist from point of view of photon? [closed]

If photons travelling with speed of light it means that time is stopped for photons and there is no any distance in Universe for them. So, does it mean that photons not exist? From point of view of ...
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1answer
60 views

Why the speed of light is 300000 km/s and not any other value? [closed]

Why speed of light is 300000 km/s and not 150000 km/s or 600000 km/s. From which it depends? Why it has the value which it has?
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32 views

Could we detect the Alcubierre drive usage if some alien civilization do it? [closed]

Is it possible to detect the warp drive usage? On which maximum distance could it be done? If we detect it, can it be a natural phenomenon (for. i.e. result of some black holes fusion)?
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0answers
57 views

Is this JWST Halo orbit plot fouled up somehow?

After looking at this plot and many others I've come to the conclusion that this plot does not represent current JWST halo orbit. If the plot is supposed to be of JWST halo... it disagrees with many ...
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0answers
60 views

Parameters of the L2 insertion burn to be done tomorrow

What parameters control the impulse to be applied in the L2 insertion burn? What parameters control when/where it is to be performed? What velocity is the impulse applied to achieve? Is the vehicle ...
1
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2answers
130 views

Could astronauts jump from a spaceship onto a spacestation and how would it be like if yes?

I saw it happen in the videogame Alien:Isolation but not sure how realistic it was. I need help understanding some orbital mechanics for a sci-fi story that I am trying to write. The scenario I ...
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0answers
66 views

A thought experiment for relativity [closed]

So if you have astronauts and space with no reference points and one is moving none of the astronauts knows who it is. But i think i figured out a way to find out. So here is my thought experiment: ...
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4answers
104 views

How can I find the x, y position of apogee and perigee, if I only have the value of distance vector (position) and velocity vector?

I am currently working on a 2D space simulator where I have two bodies; one is still and other is an orbiting object, which I can also control like a rocket. I'm using the Newton's gravity: $F = \...
2
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0answers
37 views

How do I know the exact TLE of my satellite after its deployment?

The satellites are launched in a cluster. How can I validate the TLE of my satellite in the early days following deployment, because there are more than two satellites that are close to each other and ...
1
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1answer
135 views

How did India get to the Mars?

A few years back ISRO sent their orbiter to the Mars, It is known to be the biggest feat achieved by Indian Space Research Organization over the years. It special because ISRO manage to pull this out ...
6
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2answers
445 views

What are the black stripes on Kepler's image sensor?

Kepler Focal Plane Array with each tile partly covered by something looking like a bar chart. If real, what is it? EDIT: I do not mean the seam between the two CCDs of each module but the slighly ...
3
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0answers
43 views

Are L1 and L2 orbital periods always half the orbital period of the massive bodies?

Are L1 and L2 libration point orbital periods always half the orbital period of the massive bodies? The halo orbital period of JWST is a half a year. https://webb.nasa.gov/content/about/orbit.html The ...
25
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7answers
4k views

How do satellite motors keep themselves cool and lubricated?

I'm a high-schooler and today we were taught about the car engines and we were told that in order to maintain proper lubrication in order to reduce the heating effect of friction in the pistons using ...
1
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0answers
88 views

Has an aircraft's flight ever been delayed on another planet? If so, who, what, when, where and why exactly?

For the benefit of future readers and our spaceflight-firsts tag: Question: Has an aircraft's flight ever been delayed on another planet? If so, who issued the delay order, what spacecraft's flight ...
3
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1answer
67 views

Mars at its closest is only a few light minutes away -- are different experiments performed when this happens?

While 3 minutes is not exactly real time, it still seems like remotely-controlled experiments of a different nature can be performed that could not be when Mars is farther. Is this correct, that the ...
1
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0answers
43 views

How does a fusible wire deployment mechanism work?

Situation Me and my student team are considering to use fusible wires in our CanSat to control the parachute and payload deployment. In detail, a mechanism using a fusible wire should release a loaded ...
5
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1answer
148 views

ULA just launched a very asymmetric Atlas V 511. Why does its plume look so asymmetric... after SRB jettison?

I've never noticed this before, so I'm asking. Shortly after SRB ejection, the RD-180 plume appears to be very asymmetric. Why is this? If I recall correctly, these are full-flow & there isn't any ...
6
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1answer
239 views

Can gas bubbles form in the fuel and oxidizer rocket engine pumps due to insufficient flow from the tanks?

In a staged combustion cycle rocket engine, the fuel and oxidizer are fed into turbo pumps which are in turn powered by a pre-burner. My question is how do they ensure that the fuel and oxidizer are ...
3
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1answer
64 views

Precise Orbit Determination (POD) vs GNSS accuracy; seeking references

Precise orbit determination provides performances that are not currently achievable with GNSS systems. I cannot find information of the reason for this. I imagine different possibilities: Use of ...
2
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1answer
90 views

Do Bernoulli grippers work in a vacuum?

This may be an all-time stupid question, but do Bernoulli grippers work in a vacuum? It’s pretty obvious suction cups won’t work. Bernoulli grippers use compressed air to create a suction cup-like ...
18
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3answers
3k views

Why are unused launch abort rockets jettisoned rather than used to augment thrust?

Launch abort rockets use powerful rockets. For a pad abort, they must have enough thrust to lift the capsule to an altitude where parachutes can function. The Apollo launch escape rocket had a 155,...
18
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6answers
3k views

JWST - Why unfurl before reaching L2?

I was wondering why the JWST did the unfurling of the sunshade, deployment of mirrors, before getting to its stable orbit at L2. Does the relative motion of the moving parts not affect the orbit/path ...
3
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1answer
45 views

L2 for JWST - EM barycenter used in calculation?

I’ve been reading up on two and three body dynamics, wrt to L2 for the JWST. Are the calculations for this L2 based on the sun/earth masses and locations, or on the sun/(earth+moon barycenter) masses ...
2
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2answers
68 views

With independent control of attitude and thrust direction, could JWST be kept pointing in a “safe” direction during "towing"?

Context: JWST is considered un-repairable in its current L2 location for a number of reasons: Diagnosis is difficult since JWSR has no “selfie” capability. This makes planning for any repair mission (...
3
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1answer
48 views

Is the inter-manifold transfer of JWST between Sun-Earth L2 and Earth-Moon L1 within the capability of existing propulsion systems?

Context: JWST is considered un-repairable in its current L2 location for a number of reasons: Diagnosis is difficult since JWSR has no “selfie” capability. This makes planning for any repair mission (...
6
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1answer
161 views

Question: Does JWST have hardware that could be used as a docking fixture by repair spacecraft?

Context: JWST is considered un-repairable in its current L2 location for a number of reasons: Diagnosis is difficult since JWSR has no “selfie” capability. This makes planning for any repair mission (...
2
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0answers
32 views

How to compute the satellite footprint latitude and longitude for different countour?

Given a satellite coordinates, the antenna gain pattern of the satellite (example a dish antenna at given frequency and with known diameter), the off-nadir angle and the satellite slant range i need ...
2
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1answer
131 views

How does the James Webb Space Telescope take images with individual mirror segments?

It says here (and elsewhere) that during mirror alignment the James Webb Space Telescope will take $18$ “individual images” of a star, “one from each mirror segment”. I’m wondering how this is ...
11
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1answer
2k views

Why do we use Chebyshev polynomials to predict positions of solar system bodies?

I've seen information for how to use the Chebyshev coefficients that JPL publishes, but nothing that explains why. Why isn't a simpler mathematical model used? I'm also surprised that JPL uses a ...
6
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0answers
157 views

Would it be possible to receive the transmissions from JWST as an amateur?

Would it be possible to receive the transmissions from JWST (James Webb Space Telescope) as an amateur, building your own antenna? Would the transmissions be encrypted? One source cites it using: S-...
2
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2answers
51 views

Is it (theoretically) correct to apply an equation that is derived from a hyperbolic trajectory, to an elliptic transfer orbit?

The equation in question is this one: $$v^2 = v_e^2 + v_{\infty}^2$$ and it is showed in this answer. The Escape velocity page on Wikipedia mentions a link (num. 4) to the book "Fundamentals of ...
4
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1answer
63 views

What is the average solar irradiation in low earth orbit?

I am trying to figure out how much power I can expect for a CubeSat in Low Earth Orbit. Is there some dataset or constant that describes the average rate of solar irradiation (per unit of area) in LEO?...
11
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1answer
240 views

Why making such a big deal with Max Q?

At each SpaceX launch, they always make some big deal of Max Q which most of the time comes at around 13Km and at a speed of 1700Km.h-1 But on the way back, stage 1 is at this same altitude of 13km at ...
1
vote
1answer
103 views

Halo Orbits for Dummies: Can the tilt orientation of an L2 halo orbit be modelled on Coriolis Effect?

L2 Halo orbits are often portrayed as a pair of “North” and “South” orbits. Could the difference in “tilt” around the Y axis be explained by the direction of rotation and the Coriolis Effect? https://...
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1answer
2k views

What is this South Korean rocket and why does it have separate yellow and blue exhaust plumes?

The BBC's Watching North Korea from a supersonic fighter jet (screenshot from YouTube) shows the launch of a South Korean rocket. I notice that it has both a very long, nicely expanded blue exhaust ...
9
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0answers
136 views

How well would a supersonic aircraft perform in the Martian atmosphere?

I started getting curious about this question during my Flight Test Engineering class. My professor was talking about a part of the International Standard Atmosphere that is a similar pressure to that ...
4
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3answers
272 views

Is JWST Halo orbit prograde or retrograde and why?

There is confusion in my mind over the direction of JWST’s halo orbit, depending in the source of graphics. Observing from the Earth, does JWST orbit clockwise or counterclockwise around the antisolar ...
3
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2answers
90 views

Why can n2yo somehow interpret this TLE but Skyfield can't? Why does it return nans and zeros for position?

@Rafa pointed out that there is at least one officially released TLE for the JWST mission after it left Earth orbit, and here's the latest one at n2yo.com: ...
5
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1answer
157 views

What 1960s era launch pad and vehicle is shown in this still from stock footage?

The interesting question Identify this 1960's launch site and mission? contains some screenshots of launch pad stock footage. Most are of LC39, but as @Puffin points out in a comment, one does ...

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