Question: Ships leaving atmosphere

[far-trader]

I have a word or two yet as a final summation rebuttal, but I'm too short on time at the moment.

I am highly unlikely to change my mind.

Even if you're shown to be mistaken?

In the Classic Traveller adventure Broadsword, written by Marc Miller...

...actually not quite, the adventure part was by Loren, the Broadsword part from the earlier JTAS article was by Marc.

...a definitely not streamlined mercenary cruiser lands on Garda Vilis and takes off again, obviously without
any problems.

Which is in direct and flagrant contradiction to the notes for the Broadsword by Marc Miller in the chapter of the adventure describing it

The same publication presents two incompatible views. The Broadsword lands on a world with atmo (says Loren). The Broadsword cannot land on a world with atmo (says Marc). The part that tips the scales for me is the fact that the design rules also say the Broadsword cannot land on a world with atmo. Loren disagreed, or forgot, or ignored that in the interest of having the ship on the surface for the adventure. A point that would have been served just as well by having it in orbit, without breaking the rule about not being able to land on a world with atmo.

Frankly, if Marc Miller's unstreamlined starships can do it, so can mine. :wink:

If you really want to side with Marc on this, then no, unstreamlined ships can NOT do it

If you want to side with Loren THEN yes you can do it.

It's not like Traveller isn't full of internal inconsistencies and outright errors throughout every edition allowing one to make an argument for just about any point by ignoring contradictory ones and cherry picking supportive cases

None of which is really part of my final words on this, but I've used up my break answering this, more later

 

[DFW]

I prefer to assume that spaceship drives are designed to be able to exert enough lateral thrust to allow ships to land and takeoff belly-down under power.

Perhaps they can only do this safely for short periods, with higher G-rated drives being more capable in this regard.

Simon Hibbs

Here is the logical test: Per the MGT rules, can a fighter (space craft) with a fixed forward mounted laser, fire at a target while CONSTANTLY decelerating towards its target?

Yes or no?

Can it do the same while CONSTANTLY accelerating parallel to its target?

Per the rules, no prohibition. Therefore, direction of "thrust" MUST be independent of space craft orientation in MGT.

eot

 

[atpollard]

I feel the definitions for the three hull types (shape descriptions not included) are perfect. Again 'standard hull' is like our space shuttle... some maneuverability but the tanks for enough fuel and the engines for it to lift off on it's own (either vertically by being pointed nose up, or like an aircraft) aren't included in the design and the 'air frame' doesn't generate enough lift for it to do so.

Setting aside the fact that the Shuttle Orbiter is a streamlined rather than Standard configuration, I do not think that the 'Standard' Interstellar Starship should need a substantial launch complex and boost to orbit. The 'Standard' craft should be capable of landing at a remote rock outcropping. Needing an Apollo or Shuttle-like support system should be a downgrade to the default Starship Hull.

IMO:
Streamlined should be able to glide to the ground if the power fails (lifting body)

Standard should require continuous power to land and drop like a stone if the power plant fails (but it should be able to land and take-off from a wilderness location)

Distributed may be too poorly balanced for atmospheric flight, breaking up in the jetstream and crashing if it attempts to land. As an alternative, I could certainly live with a Distributed shape landing with dificulty and minor damage and requiring an elaborate launch structure to take off [like an aeroshell that discards in orbit and costs 1000 credits per ton of ship covered].

 

[atpollard]

If you really want to side with Marc on this, then no, unstreamlined ships can NOT do it
If you want to side with Loren THEN yes you can do it.

A no brainer for me ... Go Loren! Go Loren! Yeah, go Loren!

Per the rules, no prohibition. Therefore, direction of "thrust" MUST be independent of space craft orientation in MGT.

I'd love to see someone actually embrace this and build a ship with the MD burried deep in the hull rather than where a rocket exhaust should be.

 

[DFW]

Per the rules, no prohibition. Therefore, direction of "thrust" MUST be independent of space craft orientation in MGT.

I'd love to see someone actually embrace this and build a ship with the MD burried deep in the hull rather than where a rocket exhaust should be.

The only possible issue with it being buried deep is shunting the waste heat to the hull. Other than that, no problem & I've done in the past with some large ship designs. Same for the PP & JD. Of course, all bridges on larger warships should be buried deep. Like present day CIC's on ocean going warships.

 

[barnest2]

Unless your trying to evoke images of modern day warships... which is why when I finally get round to designing the Town class from my pbp on this site, its having a bridge superstructure...

 

[phavoc]

All sniping aside, it doesn't make sense that you would restrict the movement ability of a vessel that can counteract gravity.

I'm sure everyone has heard of some of the stupider things that people have done (putting JATO bottles on a VW) in order to get more speed. We know with today's powerplants and physics that if you can apply enough thrust, you can make anything fly. Not always the way you expect it.. but still, it can fly.

This entire discussion should really boil down to what makes sense. Obviously the rules have been, umm, "slightly inconsistent" to say it politely, since they were first promulgated more than 3 decades ago.

A vessel of any type should be able to enter an atmosphere... but not every one is gonna come back out in one piece if it does it the wrong way. Ships with antigravity and landing gear and a reasonable design should be able to land and take off again under their own power. Streamlined vessels will do it with panache and grace, unstreamlined will be more ungainly and brick-like, and distributed vessels tend to land in pieces. Besides, if Lucas Trask and Otto Harkaman can lift a 2,000ft globe off the surface of Gram and put it down on Tanith then so should we. A little sci-fi trivia for ya there.

Lol! Lets tear apart a new discussion at least. This one is getting rather stale.

 

[DFW]

Unless your trying to evoke images of modern day warships... which is why when I finally get round to designing the Town class from my pbp on this site, its having a bridge superstructure...

Yes, I also liked the look of the Star Wars Star Destroyers. Just make sure your bridge deflector array has better armour.

 

[barnest2]

You can of course have that as you observation centre and then have a CiC inside the ship... that's what big capital ships have these days...

 

[rust]

Even if you're shown to be mistaken?

Most probably even then. 8)

I have thought the problem through and have come to what I consider a
consistent conclusion without any contradictions I am aware of, and this
conclusion fits my setting much better than the alternative, which would
force me to rewrite major parts of the setting.

So, unless you demonstrate that my version is based upon a true logical
error, not just a different interpretation of quotes, I consider the case as
closed. :wink:

 

[simonh]

Per the rules, no prohibition. Therefore, direction of "thrust" MUST be independent of space craft orientation in MGT.

Well the rules aren't all completely consistent, so whatever conclusion you choose you're going to need to break one or two rules somewhere. Not IMHO major, game breaking stuff though IMHO.

Anyway as I said, this is just my preferred take on it. It's how I do things in my Traveller games and not necessarily my opinion on the intent of the rules.

I assume that vessels can exert much* of their thrust in any direction, but are most efficient at 'forward' motion with the engines mounted at the back relative to the direction of flight.

Simon Hibbs

* How much? It's not something I worry about too much. Enough.

 

[GamerDude]

Please do not confuse the FORM of a vehicle with the technical limitations of 1960's rockets. Even the Shuttle needs months of preparation to launch, does that mean that Streamlined Spacecraft also cannot launch without extensive supporting infrastructure? Of course not.

ok, again... I see the shuttle as STANDARD not streamlined... if fits the book definition of "standard hull" perfectly.

To be honest, I don't understand how anyone can use the MGT definition of "Streamlined" on our space shuttle, especially with the definition of "Standard" fitting it almost to a "T". Standard, as in *(my words)* somewhat streamlined, can land but its difficult, the grace of a flying brick, and can not get off the ground under its own power.

Honestly, I almost feel that because it kind of fly's like a plane (minus propulsion on re-entry, needing booster rockets to get off the ground, etc) and it has wings/tail/rudder/ailerons... that its severe lack of vital abilities listed under "streamlined" are just invisible to people.

*sighs*

ADDED: As I pointed out many times, there is a difference between "The rules as written" and "how we see it and handle it in our own Traveller universe" The first (as written) is the baseline for discussing the second, what was written verses how we see it, do it, handle it. Rules as written are the 'hard facts', how we each 'see it/do it in our Traveller universes' are opinion, conjecture, and based on personal feelings etc.

All I can do is figure people just have a need to be 'right' and don't care if they mix crap together to make their pie.

 

[rust]

To be honest, I don't understand how anyone can use the MGT definition of "Streamlined" on our space shuttle, especially with the definition of "Standard" fitting it almost to a "T".

Do you see the space shuttle as a wedge, a cone, a sphere or a cylinder
(= standard) or as a lifting body (= streamlined) ?

NASA, for its part, describes the space shuttle as a lifting body:

The space shuttle, with a shape like a bulky glider, is actually a lifting body.

http://quest.nasa.gov/aero/events/regimes/space.html

So, if Mongoose Traveller core rules state that a lifting body is streamli-
ned, and NASA states that the space shuttle is a lifting body, it does not
seem that strange to think that the space shuttle, in Mongoose Traveller
terms, is streamlined.

And in case you still have doubts, take a look at page 100 of High Guard.
The craft there is the space shuttle, built with Mongoose Traveller rules.
It is streamlined.

But the rules' definition of "streamlined" is of course wrong, NASA's engi-
neers have no idea of the craft they designed, the author of High Guard
got it wrong, and all we do is ...

... have a need to be 'right' and don't care if they mix crap together to make their pie.

Well, you know ... :lol:

 

[GamerDude]

And in case you still have doubts, take a look at page 100 of High Guard. The craft there is the space shuttle, built with Mongoose Traveller rules.
It is streamlined.

Oh my corroded friend *coughs NOT*... again you use carefully selected tidbits and leaps of logic to make your (flawed) case.

The definitions actually have many features to them:
- Hull Shape
- Re-enters under power/not
- Difficulty in handling craft on re-entry
- Can it take off and return to orbit on its own/requires separate expensive system to do so.

Lets look at the Space Shuttle as a complete craft:
- Lifting Body, which meets "streamlined"
- Re-enters without power, a 'flying brick' as NASA as described it (not on your page)
- Is more difficult to land due to the lack of power (no fly around for second pass if you are going to overshoot, landing gear not powered and doesn't retract like they do on an aircraft)
- Must be mounted on a giant booster tank with additional SRB's (oops, Solid Rocket Boosters to you).
- NASA's page (you quoted) specifically states "That high-tech glider was the space shuttle" and that it has a "shape like a bulky glider" and is a "specially constructed spacecraft that can not launch under it's own power, but needs additional rocket engines for thrust. The shuttle is a UNIQUE lifting body in that it is a high tech glider"
The shuttle's (orbiter's) engines are not usable as an in-atmosphere propulsion system, but are classified as the "OMS or Orbital Maneuvering System" and the "RCS or Reaction Control System" engines. These are use for liftoff (with the extra fuel tank and SRB assist), to change its orbit, and exit orbit for re-entry (thats the OMS), and the RCS handle position such as rolling, changing angle, etc.


The "antique small craft, TL7" (High Guard pg 100).
- Same basic lifting body
- Re-enters under power (thrust 3 without the caveat it lands without power)
- No difficulty to land (no penalty)
- The large 'drop tank' but nothing says there is a SRB-like system required to launch the craft into orbit.
- Not described or characterized as a "high tech bulky glider that can not launch under its own power."

Again, this is a case of taking the tiny bits of info that support a person's pre-conceived understanding (you) piecing them together with tiny bits of info from a second source, and claiming victory.

Clearly, taking into account ALL of the pertinent information in the MGT books (not just tidbits) and ALL of the information on the NASA educational site these are two different crafts, one properly identified as 'streamlined' (the High Guard ship) and one clearly the definition of "standard hull".

Funny thing is, I let my wife read my posts before I put them up, and she gets it... Miss "I don't want to know about technology" gets it.

 

[atpollard]

Oh my corroded friend *coughs NOT*... again you use carefully selected tidbits and leaps of logic to make your (flawed) case ...

That was just plain bizzare.

So a streamlined lifting body (real world definition) is not streamlined (MgT definition) because the real world does not have magic drives and fusion power to allow it to fly like an airplane?

... and the 'typo' about standard hulls (MgT definition) being able to land to engage in wilderness refueling from the ocean, but being unable to lift-off from that ocean is correct.

Just Bizarre.
Time to agree to disagree.

 

[rust]

Just Bizarre.
Time to agree to disagree.

Yes, indeed. :lol:

This has reached the point where to continue the debate would be an at-
tack on a person's techno-religious beliefs, and I prefer to avoid that.

 

[atpollard]

Oh my corroded friend *coughs NOT*... again you use carefully selected tidbits and leaps of logic to make your (flawed) case ...

Time to agree to disagree.

GamerDude,
One small addendum:

Upon reflection, I wanted to at least acknowledge that I do, indeed 'get it'. The Shuttle Orbiter, plus the External Tank, plus the Solid Rocket Boosters taken as a unit could indeed be construed as a 'Standard' hull configuration rather than a 'Streamlined' hull configuration, and, if so construed, then the Vehicle Assembly Building, Crawler and Launch Pad at the Kennedy Space Center in Florida would be construed as the 'elaborate launch setup and considerable expense' required to launch a 'Standard' hull.

Actually, a good argument might even be made that it is a 'Distributed' structure under MgT rules and should not be able to fly at all.

Where I disagree with your opinion, is that 'IF' an engine existed with the performance characteristics of a Traveller TL 7 Reaction Drive and was installed on the Shuttle Orbiter, it could replace the Thermal Protection tiles for a simple titanium skin and the Shuttle Orbiter literally would be able to take-off and land like an aircraft (although one with a very long runway).

And the more fundamental area of disagreement is that I very much do not see the current Shuttle (Orbiter-ET-SRB) design as the 'Standard' or normal or typical or average design concept for TL 12 starships - which is clearly implied by MgT linking the description 'Standard configuration' to the requirement for an 'elaborate launch setup and considerable expense'.

I didn't feel comfortable ending the discussion by 'agreeing to disagree' without at least acknowledging that I understood your position, and simply hold a contrary opinion.

 

[zero]

Hia, just want to quickly clarify for my own purposes...

No hull can push through a planet without SRBs etc if it has Thrust less than the Gs of a planet (so for example a Thrust 1 ship cannot escape a 2G world w/o SRBs) unless it is streamlined (MGT definition, not RL definition), where for example a thrust 1 streamlined ship could escape a 2G world.

Also, distributed hulls are pretty much spaceships that have to stay in space, no matter the Thrust or planet G? Correct?

Is that correct? I'm not entering into the skimming discussion and such, I ask this as I may be pushing into a hard scifi story and Thrust on a ship would be a fraction of a G.

 

[rust]

Is that correct?

If the configuration of the craft provides some lift that helps to keep the
craft in the air, even a thrust which is lower than the local gravity can
enable the craft to "fly" into space. However, this is not unlimited, be-
cause a body of a certain size can only produce a certain amount of lift,
so without gravitics to eliminate the local gravity there is a point where
the combination of lift and 1 G thrust can no longer overcome the local
gravity.

Distributed hulls could almost certainly land on a planet with an extreme-
ly low surface gravity (if such a body could be called a planet), but other-
wise have to stay in space, because either the thermal stress of an atmo-
spheric entry or the structural stress of moving through an atmosphere
would seriously damage or destroy them.

 

[DFW]

To be honest, I don't understand how anyone can use the MGT definition of "Streamlined" on our space shuttle,

From the aeronautical engineering definition, the shuttle is a lifting body. So if the MGT def of streamlined is, a lifting body, and the def of "standard" is not a lifting body, there is no reality based argument to that can be made.

The only argument that can happen is if you arbitrarily change the definitions recognized in engineering.