# All Questions

10,227 questions
2k views

### Could JWST stay at L2 “forever”?

Using only reaction wheels powered by solar panel and the sunshield as a sail (in continuous active attitude control) to generate thrust from solar photon pressure in the desired direction, could JWST ...
141 views

### How will JWST manage solar pressure effects to maintain attitude and station keep it's unstable orbit?

The James Webb Space Telescope presents a huge reflective cross-section to the Sun's photons, and this can generate both torque and thrust. How will JWST manage solar pressure effects to maintain ...
1k views

### Supports in 3d printing

Do astronauts print 3D in space with supports? They are needed only because of gravity, which - on a space station - obviously is not a problem.
139 views

### Can we make super-massive Telescopes to image exoplanets?

This question has already been partly addressed here: When will we have the technology to directly observe an exoplanet with significant clarity? However, my question is focused more on the ...
84 views

### How many AGC keystrokes did an Apollo rendezvous take?

My kids have a rather nice picture book about the first moon landing titled “One Giant Leap”. I find it to be a fairly accurate retelling of the events of Apollo 11 in a poetic style. However, one ...
94 views

### Can a reaction wheel decelerate to add momentum in the same direction? [closed]

Can a reaction wheel shed weight to gain speed? Could a reaction wheel at its max spin be flipped or rearranged around 180 degrees then slowed to add to its velocity?
51 views

### Have any ideas posted on this site been successfully implemented in a space exploration endeavor? [migrated]

Has any break through been made on Space.SE and incorporated? If so which question or answer was the most helpful?
85 views

### Determining GEO Orbital Slot from TLE

I'm trying to figure out the equation based on TLE data which orbital slot a GEO satellites occupies. I have the TLE data imported into R and I wish to know what satellites are in adjoining GEO ...
117 views

### Why was the image sensor design for Juno so… odd? [duplicate]

I attended the North Eastern Astronomy Forum this year and one of the speakers was mentioning that JunoCam will not be working because of the angle of the spacecraft. He was giving a lecture on what ...
45 views

### SpaceX Avionics [closed]

Just wondering what are some avionics aboard the falcon 9 and heavy. also what are some avionics on the dragon? Just general avionics that play a pivotal role in space travel.
56 views

### What is the difference between “Air-augmented rocket propulsion” and “integral rocket-ramjet propulsion”?

While going through the topic called "Combinations of Ducted Jet Engines and Rocket Engines" in Chapter 1 of Sutton & Biblarz's Rocket Propulsion Elements, 9th Ed I found the section below. Line ...
173 views

### Is the BFB/super heavy likely to have an easier time landing than the Falcon 9 booster?

Despite the deep throttle of the Merlin 1D engine, the weight of the Falcon 9 booster is less than the force of a single Merlin engine firing at minimum throttle (See here). This means that the Falcon ...
93 views

### Properly calculating G-factor

This may sound rather simple, but I was told that technically, G-force readout should actually indicate zero-G on the earth's surface, as well as in a stable orbit. This is due to the fact that G-...
100 views

### Can an Ion engine in tow assist in launch? [closed]

This question asks: How large a body could a probe with ion engines land on and launch from? and made me think could an ion engine that is the payload be mounted in a way to assist in the launch?
8k views

### What is GPS' 19 year rollover and does it present a cybersecurity issue?

The NPR new item and audio podcast The Global Positioning System Resets talks about a 19 year cycling of something in the GPS system, but it's not clear what it is. Every 19 years, the Global ...
68 views

### Just how record-setting was the launch-to-docking time of the April-4-2019 Progress resupply mission?

Digital Trend's article 3-plus-hour supply trip from Earth to International Space Station breaks record mentions that this was even faster than the typical "fast-track" Russian launch-to-docking time ...
36 views

### Resources for planning and schedule a launch-watching day-trip in Florida?

I know some busy people in Florida who I'd like to encourage to take a break and go watch a launch. They aren't "space people" and won't be keeping up on technical blogs or NASA or industry websites. ...
170 views

### What are these big shiny metallic “lumps” on the bottom edge of each Falcon Heavy nozzle?

What are these big shiny metallic "lumps" on the bottom edge of each nozzle of each core of this Falcon Heavy image from the Teslarati article SpaceX reveals Falcon Heavy Block 5 in first official ...
2k views

### What is the white spray-pattern residue inside these Falcon Heavy nozzles?

What is the white residue in a spray pattern seen on the inside of each nozzle of each side core of this Falcon Heavy image from the Teslarati article SpaceX reveals Falcon Heavy Block 5 in first ...
69 views

### What is the O/F mixture ratio and the ISP for the SuperDraco Engine by SpaceX?

Is it safe to assume a mixture ratio of 2.16 with an ISP of 313 s for the NTO/MMH, SuperDraco Engine manufactured by SpaceX? I am referencing the 2.16 propellant mixture ratio, and estimating or ...
156 views

### Why Orion can't be used to service JWST?

Hubble Space Telescope is a marvel of astronomical tools - particularly judging by how much it moved the science. It took a lot of fixes along the way, which certainly prolonged its useful life. Its ...
102 views

### How to build a space catapult large enough to shoot a one hundered thousand ton spaceship in to low orbit?

I assume calculations start with the payload weight. A massive foundation would be needed lots of concrete and rebar meters thick. Also a harmonically sealed tunnel a thousand miles long filled with ...
92 views

### Will a spacecraft accelerate in a gravitational field via the use of a powered rotating mass?

I believe that a powered rotating mass on board a spacecraft should result in the spacecraft being propelled in a continuous increasing velocity towards the source of the gravitational field. To help ...
1k views

### Have astronauts in space suits ever taken selfies? If so, how?

Have astronauts in space suits ever taken selfies? Were selfie sticks used? If not, how was this feat accomplished?
69 views

### How many stages will be used to bring NASA astronauts to the Moon's south pole and safely back to Earth?

The question Has NASA “gone south”? Why are astronauts needed to explore the Moon's south pole? and its answers highlight the recent US executive branch's indeterminately-funded mandate. As far as I ...
66 views

### Speculation on the concept of in-space magnetic ring/rail launcher for a spaceship?

This is in reference to the question If human space travel is limited by the G force vulnerability, is there a way to counter G forces? Which, by my limited understanding, seems to point at the ...
19 views

### What Jovian system science targets would be suitable for Jupiter gravity assist flyby missions with other primary purposes?

Flying by Jupiter for gravity assist, and with the Oberth effect bonus, has been used for multiple missions to other outer planets and to comets. And has potential for use even for missions aiming at ...
120 views

### Is there any kind of research on *sub*-orbital rendezvous-ing with a space tug outside the atmosphere?

The key difference with a plain old-fashioned orbital rendezvous would seem to be that there'd be limited time to only briefly match velocities and trajectories: Let's say a vehicle launched from ...
113 views

### Can you really melt lunar regolith with microwaves?

This answer links to the 2008 Phys.org article with the catchy title NASA's dirty secret: Moon dust. The article says: Luckily, lunar dust is also susceptible to magnets. Tiny specks of metallic ...
700 views

### How thick does lunar regolith ever get? Has the thickness been measured and mapped by satellite?

Discussion in comments below the question Couldn't we just clear away the Moon Dust? have lead me to wonder if thickness of the lunar regolith is fairly well mapped by some combination of high ...
55 views

### What does the core stage of a launch vehicle mean?

I have seen the use of the term 'core stage' in the context of space launch vehicles. I am not able to clearly understand what it exactly means? I have learnt about launch vehicles having multiple ...
25 views

### How do Hayabusa-2's DCAM's work? (detachable cameras)

The screenshot below from the JAXAxxx video Mission Control Live: Hayabusa2 SCI Operation shows a diagram with DCAM3, a detachable camera that has the lucky job of watching the impact on Ryugu while ...
56 views

### Was Hayabusa-2's plastic explosive charge the largest charge detonated beyond LEO?

The BBC News article Hayabusa-2: Japanese probe set to 'bomb' an asteroid says: The charge is carried on the Small Carry-On Impactor (SCI) device. This is a 14kg conical container attached to ...
41 views

### How far will Hayabusa-2 back off before the “bomb” goes off?

The BBC News article Hayabusa-2: Japanese probe set to 'bomb' an asteroid says: The charge is carried on the Small Carry-On Impactor (SCI) device. This is a 14kg conical container attached to ...
64 views

### Puzzler: help understanding these amazing Curiosity eclipse GIFs

Starting from Curiosity Observes Sunset Eclipse: Sol 2358 I found three images in the sequence PIA23133, PIA23134, and PIA23135 which I thought would mean (but don't know for sure) that they are ...
34 views

### Why do the two Apollo 11 PSEP solar panels appear to have different backing materials?

The PSEP (Passive Seismic Experiment Package) was powered by a pair of solar panels mounted on extended arms. The one on the left (when looking towards the LEM) appears to have a matt grey backing: ...
162 views

### Could this satellite wobble in orbit creating additional orbital angular momentum?

This question asks if this type of steam engine would work: Could a steam Engine outperform other electric producing devices in space? this not a sterling engine since it has far less moving parts. ...
3k views

### Why does Arabsat 6A need a Falcon Heavy to launch

Is it just me or does a falcon heavy seem like a bit of an overkill to launch Arabsat 6A? Falcon Heavy - GEO payload: 26,700 kilograms Arabsat 6A - weight: ~6000 kilograms Wouldn't some other ...
49 views

### Are there any references about rocket Launchapd Design?

I am trying to figure out all the systems/structures/services that would be required to support rocket launches. Are there any references that describe this information? Essentially, I want to have ...
303 views

### Couldn't we just clear away the Moon Dust?

I read that "Moon Dust" is ranked by NASA as the number one challenge to building a permanent lunar base. Wouldn't it be possible, though, to send some type of lunar excavators to clear a large zone ...
64 views

### Would a terraformed Martian athmosphere even persist? [duplicate]

So I saw a question here mentioning that omnipresent idea of terraforming mars by somehow giving it more atmosphere (here it was melting/evaporating the polar ice caps). My problem with that is: ...
72 views

### Why do GEO satellites need different types of antenna?

Why do GEO satellites like the one shown in the picture below need different types of antenna? Is there a reference library or website where we can get more information on different antenna types, ...
3k views

### Can a rocket refuel on Mars from water?

Can a rocket run only on hydrogen and oxygen? Could a rocket, rover, and electrolysis machine be sent to either of Mars' poles to excavate ice to make hydrogen and oxygen to refuel an unmanned rocket? ...
72 views

### How to find an optimal number of propellent tanks?

My idea: If the propellent mass to tank mass ratio remains constant when increasing/decreasing the amount of propellant then you could increase $\sum \Delta v$, by splitting the propellent tank and ...
78 views

### Most preferred coordinate system for Launch vehicle trajectory

To integrate the equations of motion for a launch vehicle trajectory to the orbit, which is the best coordinate system to consider of the following two: Rectangular with Earth-centered inertial frame ...
55 views

### What is the nozzle extension of merlin engine and rutherford engine made of?

It is clear from the pictures, that the nozzle extension of Merlin and Rutherford vacuum engine aren't actively cooled. What is the material of construction for those nozzle extension to withstand ...
64 views

### How were Parker's sapphire elbows made?

The YouTube video The AMAZING Design of the Parker Solar Probe - Smarter Every Day 198 is quite interesting, as is the video Destin's second "Smarter" channel's video Scientist Interview: Dr. Tony ...
107 views

### Why would rocket bodies use specifically ablative coatings to reduce boil-off of cryogenic propellants? Is ablation important for this?

The end of YouTube video Delta IV Heavy Pad Tour, (with CEO Tory Bruno) - Smarter Every Day 199 points to Destin's second "Smarter" channel's video UP CLOSE Delta IV Heavy Launch Pad Tour (Tory Bruno ...
157 views

### How do astronauts maintain their neck muscles?

The human head weighs 5kg. This weight keeps the neck toned and strong. In zero gravity on extended missions how do astronauts maintain muscle and bone strength in their necks? What type of neck ...