# Tag Info

30

At least for the Space Shuttle, freezing was OK, but thawing out was bad for piping. Hydrazine contracts when it freezes, so it can 'superpack' (more fluid flows in, then freezes, etc.)...then when it thaws out, there is more than can fit in the pipe, and it can burst. In the Space Shuttle's auxiliary power unit, hydrazine plumbing was allowed to sustain ...

22

There is one area of exploration on Earth that approximates conditions on Venus, namely that of deep oil and gas mining, and a few additional areas of technology, near avionics engines, and even auto engines. The stated goal for such electronics is to function at 200 C or higher. The most promising technology for surviving high temperatures is Silicon ...

21

The big difference between the two darker RTG fins (Black and Grey) and the white RTG fins, is that the white fins were destined for use in an atmosphere (Mars). The presence of an atmosphere, even as diffuse as Martian air, would allow increased heat transfer from the RTG fins via convection and conduction, vs. the space based versions which would entirely ...

11

As a first approach, you can assume all electric power will be turned into heat. Some of the power will be used to do something first, but electrical and mechanical resistance will eventually turn all power into heat.

11

There are multiple possible improvements for moving the coolant, in pumping systems. There are piezoelectric pump and electrohydrodynamic pumping systems being worked on, with main advantage being increased reliability. One other candidate would be thermoelectric aka Peltier effect pumps. Similar tech would have ample applications in terrestrial cooling ...

11

We have plenty of metallic materials that could stand the heat of Venus's atmosphere, including copper, nickel, cobalt, iron, titanium, tungsten, and chromium, to name but a few (here's a list of elemental melting points), as well as a large number of alloys including carbon steel and stainless steel. Even the sulfuric acid isn't a huge problem with some of ...

11

When this was captured, it was at the end of the rocket flight. Looking carefully at this, I don't see any other similar nozzles. Furthermore, I didn't see any evidence of this being used in flight. I'm going to assume from all of this that it must be the vent value for the LOX, which was mentioned in the video recording immediately before. What happens ...

11

This question is intriguing because of the nature of the thermal cycles. This is the maximum theoretical efficiency of a thermal cycle (Carnot cycle), no ifs, ands, or buts about it. You can obtain very low temperatures from space, because space is at a low temperature. You'll often hear the Cosmic Microwave Background (CMB) cited for this, but that's ...

11

The insulation's job is also to prevent ice from forming on the rocket's skin (and breaking off during ascent). Shards of ice are more dangerous than chunks of foam. Even if ice were no problem, for the Space Shuttle it'd be very difficult to design insulation that comes away cleanly from the tank without hitting the orbiter. For classic rocket designs, ...

10

OK, I found an answer on my own in a caption to the NASA Image of the Day #1740 (11 August, 2010): Into the Light Reflecting on his experience as he emerged from the craft into the daylight on the Expedition 24 mission's second spacewalk, astronaut Doug Wheelock said "the colors of the Earth just explode at you as you exit toward the ...

10

I just saw this and recognized my research, ha ha. I realize this is an older question but I wanted to give my two cents. The published article is a bit deceitful in describing the technology (which frustrates me) so I wanted to straighten things out. You are exactly right in that the finite surface area will offset almost any gains from increases in ...

10

Why not a satellite-based telescope to observe Mercury in the thermal infrared? Space-borne satellites that are designed to look at the Sun (e.g., SOHO) aren't instrumented to look in the thermal infrared, while satellite-based telescopes that are instrumented to look in the thermal infrared in general don't point anywhere close to the Sun. One issue with ...

10

Orbiting satellites have to deal with darkness all the time when Earth is between the satellite and the sun, and these periods last for much longer than an eclipse does for the satellite. So although I'm no expert, I expect that any satellite designed to function above the dark side of the planet would have no problems with an eclipse.

10

The Olympus satellite (1989-053A, 20122) lost pointing and power for long enough that all the fuel froze. It was recovered after a couple months and the fuel defrosted. I couldn't easily find what fuel was used, but it must either be hydrazine or a derivative. The 21-Sep-1991 New Scientist article Nine-week battle that saved Olympus explains: Engineers ...

10

In general satellites are not "painted". They are covered in a variety of Multi-Layer Insulation (MLI) blankets with varying optical qualities. I have seen MLI in silver, black, and gold - sometimes on the same spacecraft. In addition, spacecraft often have radiators (most usually silver) and sometimes even louvers that cover radiators. A spacecraft is ...

9

Enthalpy released is about 165 kJ / mol of $\require{mhchem}\ce{CO2}$. 2,000 lb of water is about 50 kmol, requiring 25 kmol of $\ce{CO2}$. Thus long-term average heat output is 165 kJ * 25000 / 1 year = 130 watts, which is trivial compared to the overall ISS heat profile. The Sabatier equipment probably runs at a peak-to-average power ratio somewhat ...

9

The sample return capsule is designed to keep its contents below 75 °C. It is a flight-proven design, reusing technology developed for the Stardust mission. The return capsule’s structure consists of a graphite-epoxy material covered with a Thermal Protection System making use of NASA’s PICA heat shield technology – Phenolic-Impregnated Carbon Ablator. ...

8

The RTGs powered the Apollo Lunar Surface Experiments Package. This is also the first thing that comes up when you google "Apollo RTG".

8

The black tiles were used in higher temperature areas. High-temperature tiles used a black borosilicate glass coating and covered areas of the vehicle in which temperatures reached up to 2,300F. Low-temperature tiles contained a white coating with the proper optical properties needed in areas of the vehicle where temperatures reached up to 1,200F....

7

Is it normal for thrusters to “ice up”? The thing circled in your photo is a LOX vent, not a thruster. The puffy white object is solid oxygen. Your question is directly answered at T+1.05:25 in the Iridium-6/GRACE-FO webcast: Currently you can see the camera on Stage 2, looking at the upper stage engine, that white object you see is solid oxygen, very ...

7

Almost all energy from a satellite will end up as heat. The exception is power that is transmitted away, which is primarily RF only. Sound and light are not options for transmission of power usually. So just assume that all electrical power turns in to heat, with possibly subtracting out the RF energy output from the transmitter.

7

The two systems that I know of that were qualified for skip entry, Apollo and Shuttle, did so purely for cross-range capability. The skip entry would have been used for an emergency return that could not wait for a more favorable alignment with respect to the landing/splashing site. The purpose of qualifying those vehicles for skip entry was not related to ...

6

You've asked a question that is very difficult to answer accurately without in situ measurements, which apparently we don't have. The short answer: We don't know closer than ~100K! There was an experiment planned for the Mars Surveyor Lander, "MTERC" (Mars Thermal Environment and Radiator Characterization), that would have made those measurements. But that ...

6

During non-eclipse times it is normal for satellites to experience "solar outage", where the signal is cut or degraded, but not for more than a few minutes a day. This is caused by the Sun lining up directly behind the satellite (from Earth's perspective).The solar energy interferes with the signal/our ability to "read" that signal. In an eclipse, the source ...

6

Per the official NASA history of Vanguard it was for visibility and thermal control. (Bolding mine) Tousey had made some of the first calculations in the fall of 1955, contributing his knowledge of optics to ensure that protective coatings on the exterior of the booster and on the satellite shell would have ...

6

The "tilt angle" of the beam that the radiators are mounted on is called "gamma" in ISS parlance. The device is called the Thermal Radiator Rotary Joint (TRRJ) and the part of the device that passes the fluid connections across to the moving part is called the Flex Hose Rotary Coupler (FHRC). ("Alpha" is the rotation angle of the outer truss segments that ...

6

I've used a stock GoPro on a high altitude balloon that made it to 40 km, it recorded the whole way up and down (on external power). So depending on your mass and financial budget you could use this camera. At the altitude you're working at the most likely problem you'll have would be the camera over heating due to the lack of air reducing its ability to ...

6

Apparently, black was chosen despite its thermal properties. This 2005 paper was written at the end of the assessment phase where technical feasibility of the mission has been demonstrated. It shows several options were studied, including a white shield. Materials with a/e (absorption/emission constant, ed.) close to 1 could also be used. Typically ...

6

Shuttle tiles could demonstrably survive at least 27 missions over an interval of over 20 years. When Columbia lifted off from Launch Complex 39-A at Kennedy Space Center on January 16, 2003, it superficially resembled the Orbiter that had first flown in 1981, and indeed many elements of its airframe dated back to its first flight. More than 44 ...

5

Answer: Thermal radiating coating technology has improved, so they are no longer forced to be sub-optimally black in visible light. They can now be white and reflect incident sunlight to improve thermoelectric efficiency by staying cooler. The color has nothing to do with the atmosphere. It has to do with sunshine! Curiosity's MMRTG is producing about 2 kW ...

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