# All Questions

9,541 questions
128 views

### How does a Reentry Breakup Recorder survive reentry and then broadcast its data before impact?

Below are two cropped parts of File:ISS-28 Ron Garan prepares the Reentry Breakup Recorder.jpg In the Unity node of the International Space Station, NASA astronaut Ron Garan, Expedition 28 flight ...
8k views

### How was New Horizons able to direct data so precisely back to Earth?

The New Horizons space probe is sending back images of Ultima Thule, 6.4 billion kilometres away. Barring having a very large power to send information back on a very large angle, it seems to me ...
73 views

### How to achieve escape velocity from Ceres?

If I am interested in a sample return mission to Ceres using a similar propulsion technology package to Dawn, what kinds of additional propulsion would be required to land and then return? ...
193 views

### Colors of the Moon totally different in the pictures taken by Chang'e-4 in comparison with the Apollo photos. Why?

None of the pictures taken by Chang'e-4 Chinese lunar probe (see the attached images) in January 2019 have colors similar to the photos taken by Armstrong, Aldrin and the other 10 astronauts. The ...
344 views

### Are rovers useful on low gravity, low atmosphere bodies?

Are rovers useful for exploring low atmosphere, low gravity objects? Are there more appropriate exploratory vehicles being proposed? If I am interested in taking geological samples from a region ...
184 views

### What kinds of instruments do you need to detect whether liquid water/ice is on a planet?

Somewhat of a two-part question. Firstly I'm interested to know if it is expected that a planet/asteroid has water/ice on it, what kinds of scientific instruments you need to identify the presence and ...
87 views

### At what time in the Apollo 14 mission did the maneuver shown in this image happen, and what exactly was happening?

In a search for information for this answer I received this google books link of Comment: The Relevance of Space, by Arthur Kantrowitz, Bulletin of the Atomic Scientists 197, 4 April 1971, pp 32-33. ...
190 views

### Hijacked space data, notable instances of recovering images or other goodies from someone else's space mission?

The original of this GIF was tweeted here and I've reconstructed it because I don't know how to post it here (How to show this particular tweeted (GIF?) in a question? - trouble downloading). These ...
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### Did the astronauts of Gemini 4 had any realistic rendezvous simulator training of orbital mechanic effects?

Gemini 4 was the first but unsuccessful try of a rendezvous maneuver in space. There was a Rendezvous Docking Simulator in Langley, it became operational in June 1963. [Gemini 4] was launched two ...
33 views

### Which nations own tracking ships for support of rocket launches?

This wikipedia list of tracking ships contains ships of the following nations: China, France, Russia and USA. Are there no other missile range instrumentation ships for support of space operations of ...
95 views

### Why are exhaust nozzles in space shaped the way they are? [duplicate]

Why are nozzles in space shaped like a cone and not like a tube ensuring all the exhaust is directed strait?
1k views

### Why did rendezvous on Gemini 4 fail so badly?

I can't for the life of me understand why commander Jim McDivitt thought he could eyeball a rendezvous - point the nose and thrust . The futility of that technique is one of the first things even ...
94 views

### Does an airplane in orbit near the Kármán line altitude, with the air providing lift, ever reach orbital velocity? [duplicate]

The equation for an airplane in orbit with the air providing lift would be: $$\frac{GM_Em}{(R+h)^2} - \frac{\rho(h) v^2 S C_L}{2} = \frac{mv^2}{R+h}$$ $GM_E$ is Earth's standard gravitational ...
108 views

### Can satellites launched from space run only on electricity?

I need to know this fast, before February. I am not skilled in astronomy, as I am only in fifth grade. Please answer with a sensible answer, and with a simple "yes" or "no" at the beginning. Thank ...
98 views

### A gedanken on being able to navigate back to Earth

Imagine a sphere centered at Earth with a radius of 4 light years. Suppose we pick a random point on the surface of this sphere and drop someone, let us say, "Joe" there. Will Joe be able to come back ...
93 views

### Info on distances to objects in space

Can a cheap telescope tell you how many miles/km away an object is that you focus on? (Via some digital readout onscreen, or perhaps via some calculating function that you can access in its computer.) ...
56 views

### Why is the operating temperature for the Voyagers' receiver noise calculation about 1550K?

In line 10 of Table 5.2 of DESCANSO IV - Voyager Telecommunications it shows a value of the uplink receiver noise spectral density of -166.7 dBm/Hz, which is 196.7 dBW/Hz which is 2.1E-20 Watts/Hz = \$...
83 views

### Did New Horizons use its smaller medium-gain antenna for most/all downlinking of Pluto and Ultima Thule flyby data?

Brian May's New Horizons video (below) was released at about the same time that the New Horizions spacecraft passed 2014 MU69 Ultima Thule and includes a lot of technically meaningful graphics. One ...
180 views

### How to soft land on Moon?

China had sent it's own rover Chang'e-4 called Jade Rabbit/Yu Tu 2 to explore the far side of the Moon, the news said it softlanded... I remembered there is no atmosphere to deploy parachute so what ...
30 views

### What radio frequency does China use to communicate with the Chang'e-4 satellite?

I would assume this probably isn't publically disclosed information, but it doesn't hurt to ask. I am an amateur ham radio enthusiast and I want to listen in on the data.
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### How to reach a target apoapsis with a gravity turn?

Ok, here I go. I have as a project to simulate the launch of a payload by a rocket into polar orbit. Since original question was too big, let's get it into separate parts. First of all, trajectory ...
178 views

### Could the SLS reach orbit without solid rocket boosters?

Could the SLS block 1 reach orbit without solid rocket boosters, and if so, how much payload could it lift? If it couldn't reach orbit in the block 1 config, could it do so with the Exploration ...
39 views

### Effective range of a laser propelled solar sail

The ongoing Breakthrough Starshot program proposes the use of high powered lasers on Earth to be aimed at a solar sail with the intention of propelling it to the star Alpha Centauri. To be more ...
257 views

### Transmission time per day for Chang'e 4?

Congratulations for the sucessfull landing on the back side of the Moon. There is continuous line of site available for radio connection from the lander to the Queqiao relay satellite at the Earth-...
70 views

### Do Astronauts Get Any 'Alone' Time? [duplicate]

I'm thinking It would be pretty difficult to get solitary enough on the ISS, etc. Most of the astronauts are not teenagers with frequent urges I know, but it is just a matter of time until any sane/...
32 views

### are there public ideas/concepts for space mining machines?

If a company were to send a rocket into space they would need some kind of mining machine on board to mine on, for example, an asteroid. I was wondering if a company already has a good idea for a ...
272 views

### Explanation of weird values in New Horizons data?

In this answer I computed (methods given later in post) the estimated time, distance, range, and resolution for the science capture for New Horizon's closest approach to Ultima Thule (2014 MU69). ...
110 views

### Docking of Command and Service module with Lunar module

Is there any video available which is shot inside CSM during the process of docking with LM to pull it out of adapter?
70 views

### Docking of LM with CSM

I know that the CSM turned around after separation from SLA, and by using its probe, it captured the drogue of LM. The CM then issued a command to latch and pull back the locking ring of LM, so that ...
29 views

### Cis-L2 Libration Point Halo Orbit

Queqiao became the first satellite to orbit the Cis-L2 libration point (far side of the moon). Link: https://en.wikipedia.org/wiki/Chang%27e_4 Does anyone have any insight on how to model this orbit ...
100 views

### How do long range space probes adjust trajectory?

More specifically, after the main launch adjustments have been made using the primary boosters and temporary adjusting propellants how might even the slightest trajectory and orientation corrections ...
64 views

### How likely is it that a ternary cometary object forms from a binary one?

Binary comets, like 67P/Churyumov–Gerasimenko and MU69 Ultima Thule and at least a couple of others, have been observed. How likely would it be for a binary comet to again join with another object to ...
155 views

### Is helium used to power the Falcon 9 grid fins?

Is helium used as a hydraulic fluid to power the grid fins? Or for engine gimbaling? What are the pros and cons of using helium instead of hydraulic fluids?
29 views

### Direct transfers to inclined lunar orbits?

I'm trying to find examples of direct earth–moon trajectories ending in inclined low lunar orbits. I've found a few classes, such as those with plane changes between SOI encounter and capture ...
8k views

### Why are probes that tend to explore outer system always launched to go outwards instead of straight upwards or downwards?

Let's take a look at the trajectory of variety probe missions. New Horizons and Ultima Thule will be 4.1 billion miles away when it visits the Kuiper Belt object. This chart shows the path of New ...
4k views

### Could we use a narrow paradigm, say laser, to get info faster from New Horizons? (With a moon base.)

There was just a question (actually, on Astronomy) about why the data rate from New Horizons is low. Of course, even with the most directional radio antennas, the spread is enormous. I guess ...
52 views

### Satellite decommissioning and space debris removal

The problem of removing space debris is possible more challenging than decommisionning satellites. For the least, there is already a commercial offering. What is the technology gap to removal of ...
178 views

### How does New Horizons handle unexpected gravitational effects near Ultima Thule?

What are the navigation techniques used to handle the aggregated unknown effect of gravity from local and distant matter for the New Horizons space probe when it intercepted Ultima-Thule ? I am ...
205 views

### How long could it take us to reach Alpha Centauri with current technology?

I was searching somewhere on how far away the nearest star system was and what that system was. Am I correct in that it is Alpha Centauri at roughly 4.75ish lightyears? If so, a probe or ship or ...
199 views

### Where to find raw images of Ultima Thule?

I've found the raw LORRI images taken by New Horizons at Ultima Thule but haven't been able to find raw MVIC images (or data from the other instruments). Does anyone know if these are currently ...
72 views

### How can New Horizons reliably approach Ultima Thule over a huge distance? [duplicate]

How did New Horizons navigate to Ultima Thule over 80 million miles from Pluto given the chaotic effect of gravity (from unpredictable local and distant matter) on New Horizons and the fact that the ...
2k views

### What is a brake handle on the ISS crew equipment carts?

Outside the International Space Station, there is a device called a brake handle on the crew equipment carts. I couldn't imagine that device, what is it and what is it for? I found it in the book of ...
58 views

### How low does OSIRIS REx's record-setting orbiting around Bennu go?

This OSIRISREx tweet says: It's official! I'm in orbit around #asteroid Bennu -- now the smallest body ever orbited by a spacecraft. My snug path around the asteroid also sets a new record for the ...
5k views

### Why do rockets not glide back?

After stage separation, why do the rockets not glide back to Earth with wings? Is retro propulsion a better idea than gliding rockets back to 'Earth'? Take Energia-II as an example: Source: buran.ru ...
2k views

### What is carrier lock and bit lock?

I'm not sure if this question belongs here or in Amateur Radio, but during the acquisition of signal from New Horizons on New Year's Day, I heard the controllers call out "carrier lock", "symbol lock",...
117 views

### On large diameter Atlas V fairings, why is the Centaur inside the fairing?

When including an image in an answer to this question: Was New Horizons launched on a copper rocket? I noticed that for the larger diameter fairings (Atlas 501 and up) the Centaur upper stage is ...
154 views

### What was the last US manned space program?

I needed some info for a project. I tried some Google search but couldn't find an answer. US decommissioned it's space shuttle in 2011. Columbia disaster was in Feb 1, 2003. We're there any manned ...
253 views

### Why doesn't New Horizons have a tracking function

Dr. John Spencer mentioned in the live feed for the Ultima Thule flyby they're taking a series of LORRI shots along a precomputed path hoping to capture the KBO. What were the obstacles to equip the ...