# Tag Info

45

This exact problem was presented in The Artemis Project's "Why We Won't Fly a Space Shuttle to the Moon" article, so I'll just quote a few short excerpts from the points it is making, and the rest is then in the article: Vehicle Mass Dry weight of Shuttle Orbiter is about 250,000 lbs, compared to the space-only LTV's [Lunar Transfer Vehicle] weight of ...

33

NO A rocket can lift a few tons. A submarine weight thousands of tons. Propel itself in space: if you add an rocket or ion engine it could. But it's WAAAAY too heavy for any of theses to work. Similar to pushing a train by hand. A submarine is designed to keep water out. It wouldn't be airtight enough and would leak badly. A nuclear submarine needs LOTS of ...

25

Dawn has several mission objectives, including to continue testing the Ion Thruster. But why Ceres? Ceres and Vesta were chosen, because they have contrasting content, one icy and one rocky. Also, they are among the protoplanets that remain intact since formation, which (hopefully) leads to a better understanding of the formation of our solar system, ...

25

Most of your concerns can be put to rest by this image: Image credit: NASA, Source: Wikipedia For the last time in the Shuttle program, Space Shuttles Atlantis and Endeavour are placed at LC39A and LC39B in preparation for the STS-125 mission to the Hubble Space Telescope. Space shuttle Atlantis on Launch Pad 39A (left) is accompanied ...

24

The specific impulse figure of 40kN•s/kg (i.e. exhaust velocity of 40km/s) and the 31.5km/s of delta-v achieved thereby is not achievable with current propulsion technology -- it’s about 10 times the fuel efficiency of modern chemical rockets. That performance suggests something like a fusion rocket engine.

21

It wouldn't be at all. Let's look at it in a couple of different ways: The delta v required is 5.93 km/s. That's not quite, but a similar level of difficulty as launching the station in the first place! Landing either the Shuttle or the ISS on the moon would be difficult. They just weren't meant for it! There might be some parts that are usable, but in ...

21

No. And it doesn't even matter that there's no space for a crew of six no matter how small they might be or if they threw away some other pieces and try to make do. The life support of the descent module of the Soyuz TMA can only support up to three people. Since descent time is more or less constant regardless of the descent mode, and there's no way to ...

20

If the US Government ever gets back in gear, you can read NASA's Design Reference Architecture 5.0 (DRA 5) for human missions to Mars. (I have a copy, but I don't see a way to upload it here.) Here is a summary. The basic idea is to use several Saturn V's or equivalent, and put up pieces of the mission. Some parts are assembled in Earth orbit, some meet ...

17

This hinges as bit on what "as easy as" means. We clearly can't go to Mars today because we don't have the technology. We do have all the bits and pieces in theory, but we haven't build anything that can actually do it. SpaceX is famously trying to do exactly that with Starship/BFR. The discussed paper is Low-thrust trajectories for human missions to Ceres. ...

16

There's no historical precedent for simultaneous launch, but some early space program rendezvous experiments had flights launched somewhat close together. Gemini 8, 10, 11, and 12 each launched within a couple of hours of an unmanned Agena spacecraft for a rendezvous exercise. They would launch from separate pads at Cape Canaveral, LC-14 for the Agenas ...

15

Money. Most engine designs we're now using are an evolution of the space race era in one form or another, from the times when financing research in rocket engine / nozzle design wasn't such an issue. Linear spike fundamentally changes rocket design, for one engine support structure, and would as such require a revolution in engineering if someone expects it ...

14

Reentry can be hazardous, for several reasons: The debris might not burn up completely. Whether a given object will be consumed in the upper atmosphere depends a lot on its materials, shape, velocity, reentry trajectory, and even direction (to take an extreme example, a Gemini spacecraft had a heat shield on one side, so that the way the craft was pointed ...

14

There is a chamber at the German Aerospace Center designed to imitate the Martian environment. So far there are two published experiments showing that some organisms could survive in the chamber. An imitation of Martian regolith was used, and the organisms were exposed to an imitation of Martian atmosphere with the pressure, temperature range, moisture ...

12

Aerospikes are notoriously difficult to cool efficiently. With a bell nozzle, you have a minor part of rapidly expanding(+cooling) exhaust touching the broad, actively cooled nozzle - that means little conductive heat transfer, lower temperature gradient, lots of area for coolant plumbing on the outside (or within) the bell, and outer area radiating a lot ...

12

I found different specifications for the orbiter than those quoted from Artemis Project: max takeoff weight of 240,000 lbs (109 metric tons), and useful payload of 55,025 lbs (25 metric tons). If we fill the payload bay with fuel for the Shuttle's orbital maneuvering thrusters, and apply the rocket equation: \Delta v = v_e \ln\left(\frac{...

12

I found an actual reference for this, although it's in a memoir, not a technical book. Jerry Linenger's book Off The Planet states Unfortunately there is no way to squeeze more than three people into a Soyuz capsule. There are only three seats in the spacecraft. Even if one other person, without a seat, sprawled across the sitting crew, the ...

11

Interesting, been reading about this and it looks like the first moon flight reservation for Pan Am was made in 1964 actually, and then the boom in reservations came in 1968 as you say. *¹ August 1964 Pan Am accepted the reservation of Gerhart Pistor, journalist from Vienna, Austria, as the No. 1 for future flights to the moon. He paid a deposit of 20 US $... 11 You said it yourself when you mentioned weight. So far, we managed to soft land roughly two metric tons on Mars in one go, if we count both the Curiosity rover and its Sky Crane landing system (Curiosity itself is about one metric ton in mass, but both the rover and the Sky Crane actually achieved close to zero vertical velocity with respect to the martian ... 10 Several points come to mind: In most sci-fi there is gravity. At the moment we do not have a non-earth location where humans can go with gravity. If we have habitats on the Moon or Mars then there will be a degree of gravity and the situation can change. We have not yet constructed a vast spinning space station with artificial gravity as depicted in 2001 A ... 10 No, altitude is not the hardest thing about getting to space, it's getting enough lateral velocity so that you literally miss the earth as you fall. A weather balloon would get you to 23 miles (37 kilometres). Geostationary orbit is 22,000 miles (35,000 km), almost one thousand times that. In fact no balloon could get you that high since the earth's ... 10 Well, I'd say that "We can go to Ceres as easily as Mars" isn't quite true, but it's really a matter of perspective. On the one hand, measuring by fuel expenditure, specifically rocket delta-v, a journey to Ceres would be rather similar to a journey to Mars. The difference in delta-v requirement to go to Ceres is only around 400 m/s more than going to Mars ... 9 Given no time constraint, there are only two pieces missing for a manned journey to Proxima Centauri. Resources (money) and commitment. Getting there and back in a single human life time would be a totally different question/answer. There are several, drives that can get us there, the solar sail probably being the simplest and easiest to maintain over the ... 9 IANAL (I Am Not A Lawyer), and this is an unqualified opinion alone, not a legal advice, but I'd say no, since there's no proven intent to harm oneself, so it couldn't be interpreted under section 309. I asked a related question here if any government has issued an official recommendation regarding Mars One application, but sadly it didn't yet result in any ... 9 Supplementary answer expanding on @PearsonArtPhoto's answer. The first part of getting ISS (or anything else) from LEO to the Moon is lifting it's orbit around the Earth (or at least one end of its orbit) until it reaches the Lagrange point between the Earth and the Moon (EML1). The delta-V requirements for this are on wikipedia. Using "high thrust" (a ... 9 We can compute the power required to maintain speed as: $$P=\frac{C_D}2\rho A v^3$$ Assuming the hypersonic drag coefficient is around$1$and that the atmospheric density is$1\%\$ of Earth's, we get: $$\frac P A=\frac 1 2\times 0.01225~\text{kg}/\text{m}^3\times\left(5.0~\text{km}/\text{s}\right)^3 = 780~\text{MW}/\text{m}^2$$ Even on Mars the ...

9

This question assumes Mars doesn't have a magnetic field because Mars' core is frozen solid. It's not. Mars has a partially liquid core, just as does the Earth. (The Earth has a liquid outer core and a solid inner core.) Whether Mars has a solid inner core is unknown, but it certainly does have a liquid outer core (and possibly a fully liquid core). (See C.F....

8

Astronauts on most missions are allowed to bring personal items with them. Depending on what kind of mission, there are of course limits on mass and volume for their personal luggage. However, a paperback book would fit into the parameters of most missions. So an astronaut bringing a novel into space as a personal item is plausible. However, the question is ...

8

The Everyday Astronaut just released an hour long video investigating this question. Some of the main points are: Aerospikes are especially advantageous to single stage to orbit vehicles, and current space companies are not building those. There isn't really an advantage in SSTOs compared to multi stage rockets. The efficiency advantage of aerospikes isn'...

8

In addition to Brian's points (which are both correct), it's actually a misnomer that astronauts eat only dehydrated "space food". Modern food that is shipped to the ISS, for example, is actually quite good. It's still tricky to cook, but they get plenty of raw fruits and vegetables, among other things. From this TIME article: Today, the most elaborate ...

8

This turns out to be a pre-space-age thing. It's not really needed, most of the time it's perfectly fine to float around. On Skylab they provided an elaborate system of triangular grid floors and special shoes with triangular cleats to lock into them. The crew hated them and hardly ever used them. When body positioning is important (like for flying the ...

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