I found a cool scale picture

[duncan1297]

i didn't realize the Skylon is that big.

Edited January 30, 2014 by duncan1297

[astropapi1]

Dayum, Skylon is one hell of a plane.

[sgt_flyer]

Skylon is so big because of it's LH2 tanks (H2 has a reaaaaly bad density easy to see on rocket diagrams, when we see a tiny oxydizer tank next to a huge Lh2 tank, whereas kerlox tanks are much less disproportionate (lh2 is not heavier though - it just takes much more space / liter

In skylon's case, the 'low' weight compared to the size of the spaceplane will allow them a slower reentry than the space shuttle - it will allow them to greatly cut down on thermal tiles weight (as they won't need thermal tiles as effectives as the one they had on the STS)

To give an idea about the weight difference, the space shuttle orbiter was 68 tons of dry weight. Skylon is planned to weight only 53 tons of dry weight the space shuttles tiles and structures are really extremely heavy to survive g forces and temperature skylon's higher drag and lower weight will allow it to start slowing down much earlier during reentry, so it won't need a structure as strong as the shuttle. (Plus the advances in materials allow to cut down on the weight )

[spudman2]

The apollo was a tiny craft, wasn't it? Thanks for posting this, btw.

[Nibb31]

DreamChaser is missing. Orion will have a solar panel arrangement similar to ATV, not those circular panels.

[Albert VDS]

^In other words it's an old image when DC wasn't announced yet and the Orion still had circular panels in it's concept art.

An other cool comparison poster is the "Rockets of the World" poster.

This is one where someone updated it with the Falcon family:

[astropapi1]

I love how the smallest rocket on that picture is from poland...

[Captain Sierra]

Albert, the Delta V Heavy is not in that picture.

What's really laughable is that the Delta V Heavy is one and a half times the size of the Falcon 9 Heavy and yet it has only 70% the payload capacity of the F9 heavy. SpaceX FTW.

[deadshot462]

I wonder how many Mercury capsules could be put in the Space Shuttle's bay.

[Mitchz95]

I can't wait for the Skylon. It'll be every sci-fi nerd's dream come true.

Plus, it's probably the most badass-looking vehicle ever designed.

[magnemoe]

Albert, the Delta V Heavy is not in that picture.

What's really laughable is that the Delta V Heavy is one and a half times the size of the Falcon 9 Heavy and yet it has only 70% the payload capacity of the F9 heavy. SpaceX FTW.

Why? as in why is the Delta so bad?

And yes the mercury capsule is tiny, think astronauts said that you did not enter it as much as equipped it.

[N_las]

What's really laughable is that the Delta V Heavy is one and a half times the size of the Falcon 9 Heavy and yet it has only 70% the payload capacity of the F9 heavy. SpaceX FTW.

The Delta V uses hydrogen as fuel, the F9 kerosin. Hydrogen is much lighter, so a comparable amount of fuel takes far more volume. Comparing rockets by size is not fair.

[magnemoe]

The Delta V uses hydrogen as fuel, the F9 kerosin. Hydrogen is much lighter, so a comparable amount of fuel takes far more volume. Comparing rockets by size is not fair.

Thanks, that explains it, H2 is far lighter but has higher isp so you end up with an larger but lighter rocket. Main downside is that the larger size also increase dry weight eating up some of the benefit.

How practical would it be to use H2 for second stage and kerosene for first?

[maccollo]

Thanks, that explains it, H2 is far lighter but has higher isp so you end up with an larger but lighter rocket. Main downside is that the larger size also increase dry weight eating up some of the benefit.

How practical would it be to use H2 for second stage and kerosene for first?

Very practical. That's what the saturn V did, and the saturn V was awesome!

[N_las]

How practical would it be to use H2 for second stage and kerosene for first?

It is easier to use the same engines and fuel system in both stages. If you use different engines and fuels, you have to build essentially two completely different rockets and put them on top of each other.

Using the same system in both stages halves the development effort. You use the same parts, just the tanks are streched to another length, and the plumbing has to support a different number of engines. You can use the same machines in production, the same engineers, the same spare parts.

[magnemoe]

It is easier to use the same engines and fuel system in both stages. If you use different engines and fuels, you have to build essentially two completely different rockets and put them on top of each other.

Using the same system in both stages halves the development effort. You use the same parts, just the tanks are streched to another length, and the plumbing has to support a different number of engines. You can use the same machines in production, the same engineers, the same spare parts.

Understand perfectly, it would increase cost.

One thing I noticed about the recent falcon 9 to GEO mission was that their GEO capacity is low compared to the LEO one as they only uses two stages to geo, this saves money and simplify the mission but you have to haul the heavy second stage up to geo.

if you used an 3rd stage/ transfer stage to geo you should be able to increase the payload size but you would need an extra transfer stage.

[Rakaydos]

Air Force X-37b

[Armchair Rocket Scientist]

It is easier to use the same engines and fuel system in both stages. If you use different engines and fuels, you have to build essentially two completely different rockets and put them on top of each other.

Using the same system in both stages halves the development effort. You use the same parts, just the tanks are streched to another length, and the plumbing has to support a different number of engines. You can use the same machines in production, the same engineers, the same spare parts.

It's not the most efficient cost-wise, but it's certainly practical. Rockets that use or used hydrogen upper stages with cryogenic, kerosene, or solid-fueled lower stages include: Atlas-Centaur and all later Atlases, Titan IIIE and IV, Ariane 1-4, Saturn 1B, and Saturn V.

Another thing to keep in mind is that most rockets don't use the same tanks or engines for both stages, even if they use the same fuel type - in fact, doing this is only really practical if the lower stage is a large cluster, like the Falcon 9 or Saturn V (second and third stages used the J2 engine).

It's also possible to end up with "mix and match" stages, like the Centaur used on Titan and Atlas rockets (and the Delta IV's upper stage uses the same engine).

[TheBadAstronomer]

It must have been so cramped in the command module during the trip to and from the moon. 8 days is a lot of time to spend in that small area, especially with three other people.

[sgt_flyer]

Well, for apollo, the most bad missions in terms of internal space / days would be apollo 7 - with 11 days in the csm (and maybe apollo 13 where the 3 were confined in the lander for a big part of the trip) the other apollo flights (apart from apollo 8) had access to the LM's space for at least half of the mission

[magnemoe]

Well, for apollo, the most bad missions in terms of internal space / days would be apollo 7 - with 11 days in the csm (and maybe apollo 13 where the 3 were confined in the lander for a big part of the trip) the other apollo flights (apart from apollo 8) had access to the LM's space for at least half of the mission

KSP style would be to take the lander back to LKO as you had spare dV.

Wonder if anybody has left landers in Mun or other bodys orbit after docking again and forgotten to transfer the kerbals. Its the KSP style accident who probably is less realistic.

[SFJackBauer]

Well, for apollo, the most bad missions in terms of internal space / days would be apollo 7 - with 11 days in the csm (and maybe apollo 13 where the 3 were confined in the lander for a big part of the trip) the other apollo flights (apart from apollo 8) had access to the LM's space for at least half of the mission

Gemini 7 was shared by two guys (Borman and Lovell) for 14 days - and Apollo was a penthouse compared to Gemini.

[astropapi1]

Gemini 7 was shared by two guys (Borman and Lovell) for 14 days - and Apollo was a penthouse compared to Gemini.

Man, I forgot about the lenght of that mission! the Gemini capsule was not a lot bigger than a fighter cabin. How did they even make it through the entire flight?

[metaphor]

The Skylon is that big since it's also a launch vehicle, so most of its mass and volume is taken up by fuel. If you included the rockets that those other spacecraft launch on, they would be much larger.

[KASASpace]

THis looks to me to be of the wrong scale. For one thing, the Mercury capsule is not one fifteenth the length of the shuttle, and Soyuz is much smaller.