Direct (Jupiter) v. Ares...the debate continues

[Linguofreak]

I'd be interested to know specifically what you think would have been the issues with making the X-38 into a practical, MAINLY reusable crew transfer vehicle.

One of the things that the STS orbiter seems to do pretty well is de-orbit, reenter, fly and land pretty well (if the TPS stays intact, that is). It seems like the X-38 and a true crew-transfer vehicle derived from it ought to have been able to do this pretty well, also.

Well, most of it's stuff that's probably solvable to the point of tolerability and practicality for a lifting body, but I still think that a capsule is just, with current tech, an all-around safer and sturdier design, and quite possibly cheaper too. My concerns actually center more around launch.

One of the *big* things a CTV needs that lifting bodies tend to lack is a launch abort system (and it has to be something that can work on the pad. From the moment the astronauts board the shuttle to the moment of SRB sep, they are without escape options should there be a Soyuz T-10 style fire).

Another problem with lifting bodies is that they need a runway, which, considering that you generally want to try and have your ground track go over unpopulated areas (preferably ocean, what's more) during launch, poses a bit of a problem. Not an insurmountable one, but one that makes me a bit nervous in the event of a launch abort. Now the X-38's parafoil and it's 60mph landing speed probably make things a bit easier, but I still wouldn't want to land the thing on water. The Apollo command module, on the other hand...

Another concern is that lifting bodies tend break up under lower g's than capsules, which can mean the difference between succesful launch abort and LOCV in a Challenger or Soyuz 18a type situation.

 

[Urwumpe]

In the past, the coal was blacker and the snow whiter...

Objects in the rear-view mirror may appear closer than they are.

 

[Kyle]

Amen!!!!

STS was a stupid sidetrack that gained us nothing. Bring back the Saturns!

What? STS may have delayed our way back to the moon, but you cannot deny what we have learned from STS. We learned to build Space Stations, we learned how to do Untethered EVAs, we learned that we could Launch a Glider into space and Return it mostly successfully to Earth. We learned that we could have many crew members in space at once, we Learned how to do Scientific Experiments in space that were actually useful, and we were able to send spacecraft to other planets and Communication Satilites by the use of it.

 

[Zatnikitelman]

All of which could have been easily done using cheaper smaller rockets and not neccessarily using a glider. Wings are deadweight on STS. They serve no purpose on takeoff and only serve for a few minutes to make the brick with a stick land horizontally. Something like a Delta Glider, or the like relies on wings for altitude and a more efficient ascent profile unlike STS.

 

[dougkeenan]

Can you fix the Hubble with a rocket?

 

[Urwumpe]

Can you fix the Hubble with a rocket?

Yes, but not as good as with the shuttle. The payload bay will be missed, you can be sure.

 

[Kyle]

All of which could have been easily done using cheaper smaller rockets and not neccessarily using a glider. Wings are deadweight on STS. They serve no purpose on takeoff and only serve for a few minutes to make the brick with a stick land horizontally. Something like a Delta Glider, or the like relies on wings for altitude and a more efficient ascent profile unlike STS.

So, a EELV Could lift up Hubble?
A EELV could Lift up Kibo?
A EELV could Lift up all those Station Parts?
A EELV could Bring the Chandra X-Ray into Orbit?
No.

 

[Spicer]

I agree. Despite its drawbacks, the STS has functioned as an orbital construction vehicle.

It's a brilliant design that has some serious flaws. It does function amazingly well. Many of the accomplishments of the shuttle could not have been accomplished by any rocket, even today.

 

[GregBurch]

One of the *big* things a CTV needs that lifting bodies tend to lack is a launch abort system (and it has to be something that can work on the pad. From the moment the astronauts board the shuttle to the moment of SRB sep, they are without escape options should there be a Soyuz T-10 style fire).

I'm guessing that you could go the same route as was posited for the X-20 -- have the orbital insertion transtage serve as an abort motor from T-0 on up.

 

[GregBurch]

So, a EELV Could lift up Hubble?
A EELV could Lift up Kibo?
A EELV could Lift up all those Station Parts?
A EELV could Bring the Chandra X-Ray into Orbit?
No.

This begs the question of whether we should have combined heavy lift with crew transport. If you start from the proposition that the two don't make sense being combined (as I do), then you don't follow Apollo with STS -- not by a long shot.

The history is completely clear: The combination of these two functions was a political move to keep NASA funded at as close to Apollo levels as possible.

 

[GregBurch]

Can you fix the Hubble with a rocket?

If I'm getting your meaning, the answer is "yes" -- IF you work in a step-by-step fashion to build a robust, permanent space infrastructure, instead of putting all your eggs into one giant, complex basket.

By 1990, we could have had a small but sensible space station and a tug that could have retrieved payloads like Hubble, brought it to the station for repairs, and returned it to its working orbit.

That is, if we hadn't put all our eggs into one giant, complex package.

 

[GregBurch]

What? STS may have delayed our way back to the moon, but you cannot deny what we have learned from STS. We learned to build Space Stations, we learned how to do Untethered EVAs, we learned that we could Launch a Glider into space and Return it mostly successfully to Earth. We learned that we could have many crew members in space at once, we Learned how to do Scientific Experiments in space that were actually useful, and we were able to send spacecraft to other planets and Communication Satilites by the use of it.

Yes -- all of that and more could have been done in the same time-frame, and cheaper, with a different approach.

 

[Kyle]

You couldn't fix hubble with a Rocket, that would require man skill.

 

[GregBurch]

You couldn't fix hubble with a Rocket, that would require man skill.

If I'm getting your meaning, the answer is "yes" -- IF you work in a step-by-step fashion to build a robust, permanent space infrastructure, instead of putting all your eggs into one giant, complex basket.

By 1990, we could have had a small but sensible space station and a tug that could have retrieved payloads like Hubble, brought it to the station for repairs, and returned it to its working orbit.

That is, if we hadn't put all our eggs into one giant, complex package.

.

 

[Tschachim]

So, a EELV Could lift up Hubble?
A EELV could Lift up Kibo?
A EELV could Lift up all those Station Parts?
A EELV could Bring the Chandra X-Ray into Orbit?
No.

Well, the Russians have "only rockets" since ever and have space stations and all that since the 1960s, so I suppose yes...

Apropos Russians, I'm not that eager to the Saturn I(B) back, but I'd like to see parts of the Russian stuff back, Energia technology for example, as the Atlas V does. But that's just my personal opinion.

Cheers
Tschachim

EDIT: I might add that you're correct if you mean it literally. Hubble, Kibo etc. were designed to be launched in the Shuttle payload bay since the beginning, so it would be at least rather expensive to modify them to be launched on top of an EELV.

 

[Urwumpe]

Hubble for example could have been build without manned service missions in mind - it is almost perfectly same as a class of spy sats launched by the Titan IV.

The difference for them is just: When the mirror was badly manufactured, they would just launch a new one...

And Chandra is not soo much special, compared to the XMM launched by an Ariane 5.

 

[GregBurch]

Hubble for example could have been build without manned service missions in mind - it is almost perfectly same as a class of spy sats launched by the Titan IV.

The difference for them is just: When the mirror was badly manufactured, they would just launch a new one...

And Chandra is not soo much special, compared to the XMM launched by an Ariane 5.

I actually think on-orbit servicing is great. But the idea of doing each task for each object of servicing piecemeal as a separate mission with the giant repair truck is what gets me.

 

[Linguofreak]

I'm guessing that you could go the same route as was posited for the X-20 -- have the orbital insertion transtage serve as an abort motor from T-0 on up.

I'm not too familiar with the design of the X-20, but the problem I see there is that for orbital insert you generally want low-thrust/high ISP, whereas for launch abort you want high thrust/low ISP.

Assuming that you can get a decent compromise there, though, that problem is taken care of. My other objections remain, though.

 

[Urwumpe]

I actually think on-orbit servicing is great. But the idea of doing each task for each object of servicing piecemeal as a separate mission with the giant repair truck is what gets me.

Well, you can't do all effective with smaller crafts. You can't compare satellites with cars, which you can effectively park anywhere and only require a full workshop only for special repairs.

A satellite is more like a ship - for repairing it, you need to dry dock it. You need a EVA work platform for most such works. Using a tug to bring a satellite to a space station is not very effective as the docking of the crew + spare parts + bring the satellite to the station is with current technology more expensive as bringing a EVA work platform with spare parts and crew directly to the satellite.

Which the STS effectively was. It just had a too expensive heat shield.

 

[Linguofreak]

You couldn't fix hubble with a Rocket, that would require man skill.

But you don't need the shuttle to get astronauts to Hubble. It can be done with a capsule.