# Tag Info

90

Technically, yes, it would be easier to put people on Venus. You need less of a kick for the interplanetary trip and slowing down is trivial with that dense atmosphere...one of the Pioneer Multiprobe sub-probes made a soft landing despite only being designed as atmospheric probes. However, the surface temperature stays close to 464 °C, with over 90 ...

83

Reliability. Any rotating station needs non-rotating components: solar panels need to face the Sun, radiators need to be shadowed, docking points need to be non-moving, and so on. Making a rotating joint that can last decades is hard; if the hub of a rotating station seizes up, the resulting accelerations are likely to tear the station apart and kill ...

63

Are there failure modes that cause loss of pressure but not rapid, unplanned disassembly? Yes. The 3-man crew of Soyuz 11 died when a valve was jolted open, venting out all the cabin air supply. Soyuz was redesigned after that accident to carry two crew in pressure suits instead of 3 crew in shirtsleeves. (I believe they now carry three in pressure suits.) ...

60

Why were the SpaceX Crew-1 astronauts backed up by guards with automatic weapons? A NASA crew launch is a highly-visible symbol of US national pride. I mean, the slogan for the whole campaign is Launch America, and the message has always been "Launch American astronauts from American soil in an American capsule on American rockets (for the first time ...

50

I'll add one or two more items to Mark's excellent list. Stability - large rotating platforms (and they have to be large to produce useful artificial gravity) are subject to all sorts of precession. Cost. The ISS was not cheap. Now imagine just getting maybe 50 ISS' worth of mass into orbit, assembled, and then enough fuel to spin it up.

49

TL;DR: It was so busy getting stuff done, it didn't care. Being old, slow, massive and inefficient (by any modern standards, not by those in 1965) is a huge benefit when it comes to radiation hardness. Let's start with the memory: Changing a bit in current S(D)RAM cells is trivial - introduce a bit of charge in the wrong place and the bit is lost. This ...

48

As others have already pointed out, getting humans to Venus would be marginally easier than getting them to Mars. Let's consider survival on Venus in a little more detail though. Although there haven't been any manned missions to either Mars or Venus, there have been unmanned missions to both. So let's consider how long those unmanned missions have survived. ...

47

Delta-V to LEO is about 10 km/s. From there to C3 (Earth escape) is another 3.2 km/s. It's just another 30% delta-V. The problem is the Tyranny of the Rocket Equation. More delta-V means more fuel. More fuel means more mass. More mass means more fuel. How much more? Fuel costs scale according to $e^{\frac{\Delta V}{v_e}}$, that is e to the power of the ratio ...

46

Assuming this isn't a troll question and you are serious about wanting to know what computers are used for in spaceflight (prior to 1988), NASA has a great resource for you: Computers in Spaceflight (PDF, 494 Mb) From the introduction: Computers are an integral part of all current spacecraft. Today they are used for guidance and navigation functions such as ...

45

Yes, there are people whose sole job is "mission design." They design the trajectory that a spacecraft should follow to fulfill its mission and all of the maneuvers needed for that to happen. Some companies specialize in mission design consulting, like Space Exploration Engineering, Advanced Space LLC, or the X Team from JPL (although the latter ...

43

These are mirrors. Even SpaceX's slick spacesuits have limited mobility, especially when the astronauts are strapped into the seats. The mirrors allow them to see corners of the spacecraft that they can't otherwise see because the helmet is in the way, they can't turn their head, they can't leave the seat, or similar. For example, if you try to look up, ...

43

Partial answer covering only Is this a new thing, or were similar military guards around to guard Shuttle crews as well? It is not a new thing. Photo by former colleague Michael Grabois at STS-101 crew walkout, 2000. The guards were not only on the ground. Image source Personal photo at STS-135 launch, 2011.

38

It always flew crewed. After the Columbia failure, provision was made to fly a damaged Orbiter uncrewed back to a west coast landing site, leaving the crew on the ISS. This was called the Remote Control Orbiter and it required an In-flight Maintenance kit to be installed after docking at the ISS. It was never used. The smallest number was two (STS-1, 2, 3, ...

37

They keep the ISS at a pretty comfortable temperature and humidity level, so there's not much sweat accumulation except when they're working out. For that, they use towels. The sweat that they do produce that evaporates (along with the water vapor they exhale) gets collected as part of the water processing system and recycled into drinkable water.

37

It's a good question, followed by many relevant responses so far. I'll focus on the physiology aspects. Research had been conducted for decades prior to ISS launch on creating artificial gravity through spinning. The short of it is: the human balancing system (inner-ear plus brain) cannot not handle the spinning motion on the scales of what humans could ...

35

Between them, Spirit and Opportunity spent the equivalent of 22 years performing geology fieldwork on Mars. In that time, they managed a scientific output comparable to what a single geology grad student could do in two weeks. Between them, Luna 16, Luna 20, Luna 24, and Chang'e 5 returned about 2.3 kg of material from four sampling sites. Neil Armstrong, ...

35

The Venus flyby does indeed make the mission shorter, but it has some pretty serious negative consequences as well. The mission spends much more time in deep space. Approaching the sun will increase the amount of radiation exposure by a large amount. The thermal design would need to be rethought to survive that close to the Sun. The time on Mars for a Venus ...

34

It's not hard, it's just expensive. We know exactly how to do it. Compare this to building computer processors with 1nm transistors, or making reliable self-driving cars. Those are both things that we currently don't know how to do, and we don't even know exactly how to get better at doing them. Even going past low Earth orbit to another planet, like Mars, ...

33

The contract between SpaceX and NASA required two demo flights (and SpaceX voluntarily did the in flight abort, notice Boeing is not doing that). They did an unmanned demo flight with Dragon C201, that launched Mar 2, 2019 and docked to the PMA/IDS on the ISS. Then they did the in flight abort, Jan 19, 2020 with the C205 capsule. Then they flew the Demo-2 ...

32

One of the most important reasons is that robots don't make great interview partners. A significant part of space missions is outreach and inspiring people. Another important part is giving people a different view of our planet. Astronauts over and over again describe the awesome feeling of being able to see how small and fragile our planet is, and the ...

28

Your spacecraft would need to be several orders of magnitude larger than the Saturn-Apollo. No human pilot has successfully performed a rendezvous without a computer. Note that rendezvous is bringing two spacecraft close together in orbit, position, and velocity. Docking is the actual physical contact between two spacecraft. The latter can and often is ...

27

First of all, the ground team could have, and in fact did, do most of the orbital navigation remotely. This report mentions the fact that the on board computer was secondary for Apollo 8, with primary being systems from the ground. The spacecraft did have to do a few things, including making some realtime adjustments during the landing based on the actual ...

27

There was a proposal to add an experimental rotating habitat: Nautilus-X. One of those wonderfully tortured backronyms: Non-Atmospheric Universal Transport Intended for Lengthy United States Exploration - eXperimental. Its primary purpose was to extend how long humans could live in space not only through artificial gravity, but also storage for consumables, ...

25

Short answer: Yes. Mars is not windy enough to properly wave most flags. Long answer: In storm conditions, a flag constructed out of a very light material would be able to properly wave. If we take a standard flag, say 3'x5' that's made of 200g Nylon $\ell= 1.5$ meters $h_f = 0.9$ meters $W = A * 0.2 * g_{Mars}$, $W = 1$ Newton Going off the calculations ...

23

If you want an example manifest for one logistics flight, that's available. Search terms...suggest "ISS Cargo Manifest" From SpaceX 2 Cargo Manifest (see link for details) 81 kg of crew supplies (food, clothes, paperwork) 25 kg of international partner experiments 323 kg of NASA experiments 3 kg of EVA tools 135 kg of ISS hardware 8 kg of PC parts ...

23

“Do I have a very naive concept of space travel?“ - honestly, yes you do. Here is an excerpt from Don Eyles’s wonderful book Sunburst and Luminary: An Apollo Memoir: Guidance would be processed every two seconds, repeatedly correcting and refining the trajectory based on new data from navigation. Into the guidance equation, with each turn of the crank, went ...

22

December 2011. At that time, Soyuz TMA-03M flew to ISS. On its successor, TMA-04M, its SMI-4 light was replaced with a LED headlight. https://en.wikipedia.org/wiki/Soyuz_MS phrases it: the old halogen headlights, SMI-4 (СМИ-4), have been replaced with the LED powered headlight SFOK (СФОК).

21

According to an authoritative-sounding post on collectspace here, it's statute (which matches my recollection). Edit: OP @costrom found an FAA document Fact Sheet – Commercial Space Transportation Activities which confirms it.

20

Each shuttle mission had significant amounts of rope / cable / cordage aboard. tl;dr sky genies - 40 feet of rope per crewmember RMS rope reel - 80 feet of rope astrorope - 20 feet of rope per EVA crewmember (development item, not normally flown) EVA winch - 24 feet of rope EVA safety tether reel - 35 or 55 feet of cable, per EVA crewmember other ...

19

Why this wouldn't work? It works for the Earth; the reason why it is not implemented in space is purely in the engineering limitations. Cyanobacteria live in water, humans live in air. Gravity is good at separating water from air, leaving a surface for the gas exchange. Microgravity is very good at mixing everything, so we should think about another ...

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