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Entering Atmosphere
Posted: Mon Aug 22, 2016 1:07 am
by dragonfett
Could a person in Full EBA (or has some other protection from the vacuum of space and sufficient air) use the spell/talisman Impervious to Fire/Energy to avoid damage from entering a planet's atmosphere?
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 1:14 am
by Zamion138
I suppose, for the heat, but not the impact.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 2:23 am
by dragonfett
No, but there are other options for that (Contra-Grav Packs, Fly as the Eagle, etc.).
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 2:34 am
by Marcethus
Standard EBA is rated for 200 degrees centigrade, CS Dead Boy Armor is rated for 300 degrees centigrade. The oxygen supply could be an issue. Standard has 5 hours CS has the same. The Radiation shielding might also be an issue for standard armor as it says minimal vs the CS's flat statement of radiation shielded.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 12:01 pm
by drewkitty ~..~
It all depends on what speed the char is going before hitting atmo.
◆If they are in orbit, going orbital speeds, they would be cooked before they slowed down.
◆If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 12:28 pm
by dragonfett
drewkitty ~..~ wrote:It all depends on what speed the char is going before hitting atmo.
◆If they are in orbit, going orbital speeds, they would be cooked before they slowed down.
◆If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
Why wouldn't Immunity to Fire or Immunity to Energy prevent them from getting cooked?
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 12:47 pm
by drewkitty ~..~
dragonfett wrote:drewkitty ~..~ wrote:It all depends on what speed the char is going before hitting atmo.
◆If they are in orbit, going orbital speeds, they would be cooked before they slowed down.
◆If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
Why wouldn't Immunity to Fire or Immunity to Energy prevent them from getting cooked?
Do those protect from environmental factors? No, they don't. So the answer to your question is No.
The char would have to have to be impervious to
heat to withstand the heat from de-orbiting from orbital speeds without slowing down before hitting atmo.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 2:14 pm
by Marcethus
Burster's are immune to heat. So one of them if they had the armor to withstand vacuum and the oxygen supply to take care of it.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 3:18 pm
by Zamion138
So is re-entry heat mdc heat or sdc heat?
The radiation is probably the biggest killer, but how long can you sit in sdc flames/fire before it bakes your mdc armor? Or rather the person in the suit.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 3:44 pm
by dragonfett
Looking of the the spells, I just found a great use of the spell "Resist Fire"
With "Resist Fire", the person protected by the spell suffers no ill effects from heat.
So would entering a planet's atmosphere being protected by "Resist Fire" and "Impervious to Fire" be sufficient to survive at orbital speeds?
(Marcethus, all of the body armors from DB 2: Phase World says that they provide sufficient protection from radiation, solar flares, and other common space dangers to be used in space).
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 5:18 pm
by drewkitty ~..~
*Yawns* Fire is not heat.
While yes those two spells would fortify the char against being directly damaged by the plasma ball of a orbital speeds atmo entry. They still don't protect the char from the heat bleed through that will happen.
With spells and psionic powers there isa matter of timing. Too Soon and any protection will run out. Too late …its too late.
As to a "How to do it?" *shorts* easy…Energy Field spell cast in a plane in front of a spherical EF to ward off the plasma wrap-around. The planer EF will probably have to be renewed every minute or so. Cause I firguer that like me most GMs (Like I would) would rule that re-enter is an MD event except for heat shielded spacecraft. (Three to four inch thick tiles were on the space shuttle.)
------
Problem #2 Not Tumbling during re-entry.
Re: Entering Atmosphere
Posted: Mon Aug 22, 2016 9:32 pm
by Marcethus
dragonfett wrote:Looking of the the spells, I just found a great use of the spell "Resist Fire"
With "Resist Fire", the person protected by the spell suffers no ill effects from heat.
So would entering a planet's atmosphere being protected by "Resist Fire" and "Impervious to Fire" be sufficient to survive at orbital speeds?
(Marcethus, all of the body armors from DB 2: Phase World says that they provide sufficient protection from radiation, solar flares, and other common space dangers to be used in space).
I wasn't looking at DB2 I was solely using RUE as my reference point.
Re: Entering Atmosphere
Posted: Tue Aug 23, 2016 10:34 am
by Nightmask
dragonfett wrote:Looking of the the spells, I just found a great use of the spell "Resist Fire"
With "Resist Fire", the person protected by the spell suffers no ill effects from heat.
So would entering a planet's atmosphere being protected by "Resist Fire" and "Impervious to Fire" be sufficient to survive at orbital speeds?
(Marcethus, all of the body armors from DB 2: Phase World says that they provide sufficient protection from radiation, solar flares, and other common space dangers to be used in space).
No because it's not just heat it's a steady brutal stream of air molecules pounding away at the object dropping towards the Earth. You'd be slamming into the air so hard and so fast that even if you were perfectly immune to the heat and flame it'd still end up ripping you apart without way more protection than just that.
Re: Entering Atmosphere
Posted: Tue Aug 23, 2016 12:00 pm
by dragonfett
Nightmask wrote:dragonfett wrote:Looking of the the spells, I just found a great use of the spell "Resist Fire"
With "Resist Fire", the person protected by the spell suffers no ill effects from heat.
So would entering a planet's atmosphere being protected by "Resist Fire" and "Impervious to Fire" be sufficient to survive at orbital speeds?
(Marcethus, all of the body armors from DB 2: Phase World says that they provide sufficient protection from radiation, solar flares, and other common space dangers to be used in space).
No because it's not just heat it's a steady brutal stream of air molecules pounding away at the object dropping towards the Earth. You'd be slamming into the air so hard and so fast that even if you were perfectly immune to the heat and flame it'd still end up ripping you apart without way more protection than just that.
In your opinion, how much damage would be caused by hitting the air itself, and at what speed would you have to slow down to so that you are no longer taking damage from just moving through the air?
Re: Entering Atmosphere
Posted: Tue Aug 23, 2016 1:33 pm
by drewkitty ~..~
dragonfett wrote:snip... and at what speed would you have to slow down to so that you are no longer taking damage from just moving through the air?
drewkitty ~..~ wrote:snip...
◆If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
Re: Entering Atmosphere
Posted: Tue Aug 23, 2016 4:03 pm
by Marcethus
At certain speeds hitting the atmosphere would be like hitting solid ground. It's why you see on various science fiction shows that they will skip off of the atmosphere in some very dangerous maneuvers to try and save themselves from burning up in the atmosphere.
Re: Entering Atmosphere
Posted: Tue Aug 23, 2016 6:38 pm
by dragonfett
drewkitty ~..~ wrote:dragonfett wrote:snip... and at what speed would you have to slow down to so that you are no longer taking damage from just moving through the air?
drewkitty ~..~ wrote:snip...
◆If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
What is Spaceship One?
Re: Entering Atmosphere
Posted: Tue Aug 23, 2016 9:16 pm
by drewkitty ~..~
The ansari X-Prize winner.
Re: Entering Atmosphere
Posted: Thu Aug 25, 2016 4:10 pm
by J_cobbers
dragonfett wrote:drewkitty ~..~ wrote:dragonfett wrote:snip... and at what speed would you have to slow down to so that you are no longer taking damage from just moving through the air?
drewkitty ~..~ wrote:snip...
◆If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
What is Spaceship One?
It's the first spaceship ever, hence it's name.
Or if you don't believe that bit of baloney, there are theses thing called google and wikipedia:
https://en.wikipedia.org/wiki/SpaceShipOneBut more on point to your original question this should give you an idea of the forces involved with a lot of space craft re-entry:
https://en.wikipedia.org/wiki/Atmospheric_entry
Re: Entering Atmosphere
Posted: Thu Aug 25, 2016 6:23 pm
by drewkitty ~..~
Both are on point because I pointed out BOTH of the options for entering the atmo. of a planet which can be broadly called 'falling'.
The other way is to is using some sort of drive to lower the ship or other to the surface. Space elevators fall into this option.
The use of the SpaceShipOne as an example for falling to the planet after canceling out the object's orbital speed was 'On Point'. Because it demonstrated that you don't have to be a fireball to enter an atmo.
Re: Entering Atmosphere
Posted: Fri Aug 26, 2016 2:22 am
by dragonfett
drewkitty ~..~ wrote:The ansari X-Prize winner.
At first, I had honestly thought it was some space ship from some gaming module or some such. I had so many other things going on I had forgotten to Google it.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 1:14 pm
by glitterboy2098
to be fair, SpaceShipOne may not be a good example here because of a few factors..
1.) it is not an orbital craft. it is sub-orbital, only reaching 100km (62 miles) altitude. this is technically space by the legal definition, but it still on the edge of the atmosphere. it is called the Karman Line, and represents the point where the atmosphere is so thin it no longer is a primary factor for aerodynamic purposes. the lowest possible orbit is 160km (99.4 miles), and those are extremely unstable due to atmospheric drag.
2.) SpaceShipOne, being a suborbital ship that only just barely leaves the atmosphere, does not have to dump all that much speed to return to earth without much friction induced thermal heat. it only reaches about mach 3.5 at the fastest.. you need closer to mach 25 to reach low orbit
3.) SpaceShipOne dumps speed by way of aerobraking. it's wings shift position to increase the amount of atmospheric drag it experiences, gradually slowing the ship down as it falls. the term they came up for this is 'shuttlecocking' after the conical projectiles in badminton, which use a similar drag inducing concept to orient themselves in flight. in effect, they turn the whole ship into a giant parachute and coast down. once they've slowed to subsonic speeds they switch the wings back to glider orientation and glide back.
so it really isn't a good basis for comparison here, since it does not reach the altitude and velocities involved in a true reentry of the sort being inquired about.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 1:35 pm
by drewkitty ~..~
Again, GB SpaceShipOne was an example of specific data set. That data set is particularly limited in that aspect that all orbital speed was negated before falling into an atmosphere. For that data set it is a good real world 'getting the idea I'm talking about across' example.
As to differentiate that idea from the capsule or shuttle with heat shield plasma fire ball atmo. braking idea of atom. entry that is burned into the culture of today's real world.
In the 3G setting, such a fiery entry would only be for drop shuttles making an assault drop or for training.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 4:34 pm
by glitterboy2098
except that using it as a dataset is pointless because it
never truly left atmosphere,
never reaches orbit or orbital velocity, and
and does its speed shedding while in atmosphere.we do not have any real world examples of cancelling out ones orbital velocity prior to entering atmosphere.
all of our spacecraft use aerobraking in atmosphere to slow down from orbital speeds, because we don;t have the drive power or efficiency to allow anything else.
it is like trying to use a Moped to argue about the performance of a Formula 1 car..
addressing the Original posters question..
if you can protect yourself from the heat you have a chance, but the air rushing past you, especially if your using a spread eagled type pose to maximize your drag, would likely inflict a lot of bruising, broken tendons, broken bones, and other such serious injuries before you slowed to the speeds skydivers start at. though you might want to look at the record altitude skydives to get an idea what such an experiance might feel like once you have slowed down.
that said, there was a lot of research into personal reentry systems during the early space race, beforeit was abandoned as too dangerous with IRL tech.
http://www.astronautix.com/r/rescue.htmlthe one i think you should look at is the MOOSE system, aka
http://www.astronautix.com/m/moose.htmlbasically a thick mylar bag which the astronaut climbs into, inflates with hard setting foam on one side, and then rides down ballistically for aerobraking. it had a small rocket pack to give the initial orbital change needed to get to the atmosphere, and to do a bit of course adjustment prior to reentry.
the mylar and foam help keep the astronaut from burning up, acting as an ablative shell.. but the margin of safety was so thin as to be almost non-existent so it was dropped in favor of larger, more solid concepts.
in phase world though, i could see a TW'd version using the anti-heat spells to prevent the bag and foam from burning away, and the foam would help prevent the airflow from causing serious injury to the astronaut inside. still would be risky though.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 4:58 pm
by drewkitty ~..~
glitterboy2098 wrote:except that using it as a dataset is pointless because it never truly left atmosphere, never reaches orbit or orbital velocity, and and does its speed shedding while in atmosphere.
we do not have any real world examples of cancelling out ones orbital velocity prior to entering atmosphere. all of our spacecraft use aerobraking in atmosphere to slow down from orbital speeds, because we don;t have the drive power or efficiency to allow anything else.
it is like trying to use a Moped to argue about the performance of a Formula 1 car..
You are TOTALLY missing my point.
It is only an example of the ""IDEA"" that if you Are Not Going Orbital Speed you don't cause a fireball because you have already slowed down! As such the air does not heat the MDC armor or shuttle or Whatever so much as to
need a :: heat shield! THIS is the idea it is an example of. Nothing else. It is NoT an example of a :: ""Real"" Spacecraft…..not even a 3G space craft.
So your objections that it is not an example of a ""Real"" spacecraft is hot air cause that is not what I'm using it as example of of a real spacecraft. I Agree that it is
not a ""real"" spaceship. Even as it was used it was just a demonstrator craft. Which demonstrated that
"if you are not going orbital speed you don't need a heat shield cause you don't need to slow down from orbital speeds by ramming into the atmosphere causing a plasma-fire-ball."" Hey, That sounds like what I'm using it as an example of.
(Yah, it was built to win the X Prize too, but that is outside the discussion here.)
And since we ARE talking about the 3G setting we Are Not talking about the real world. So bringing in
real world "we don't have engines that do that" is just distracting from the subject at hand because
in the 3G setting they Do Have engines that can do that.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 5:08 pm
by glitterboy2098
except that
still is a bad comparison because SpaceShipOne is actually moving at it's fastest when it starts it's fall back to the ground and its aerobraking.. while your arguing that it proves that you don't need aerobreaking at all. which is clearly untrue.
just because it is suborbital does not make it equivalent to a ship that used a drive to cancel out its orbital velocity vectors.
addressing the Original posters question..
if you can protect yourself from the heat you have a chance, but the air rushing past you, especially if your using a spread eagled type pose to maximize your drag, would likely inflict a lot of bruising, broken tendons, broken bones, and other such serious injuries before you slowed to the speeds skydivers start at. though you might want to look at the record altitude skydives to get an idea what such an experience might feel like once you have slowed down.
that said, there was a lot of research into personal reentry systems during the early space race, beforeit was abandoned as too dangerous with IRL tech.
http://www.astronautix.com/r/rescue.htmlthe one i think you should look at is the MOOSE system, aka Man Out Of Space, Easiest
http://www.astronautix.com/m/moose.htmlhttp://www.boggsspace.com/strange_but_true.aspbasically a thick mylar bag which the astronaut climbs into, inflates with hard setting foam on one side, and then rides down ballistically for aerobraking. it had a small rocket pack to give the initial orbital change needed to get to the atmosphere, and to do a bit of course adjustment prior to reentry.
the mylar and foam help keep the astronaut from burning up, acting as an ablative shell.. but the margin of safety was so thin as to be almost non-existent so it was dropped in favor of larger, more solid concepts.
in phase world though, i could see a TW'd version using the anti-heat spells to prevent the bag and foam from burning away, and the foam would help prevent the airflow from causing serious injury to the astronaut inside. still would be risky though.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 5:12 pm
by drewkitty ~..~
Go back and reread all my post and see if your arguing with me is pointless.
From my PoV you are pointlessly arguing with me.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 5:13 pm
by dragonfett
The whole reason I am asking is because I am currently running a game set in the UWW section of the 3G and I was imagining that this could be one way to get a lot of troops from a troop carrier to the ground by using talismans (because I figure it would be cheaper in the long run for them to create a ton of talismans rather than a bunch of TW equipment).
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 5:22 pm
by drewkitty ~..~
dragonfett wrote:The whole reason I am asking is because I am currently running a game set in the UWW section of the 3G and I was imagining that this could be one way to get a lot of troops from a troop carrier to the ground by using talismans (because I figure it would be cheaper in the long run for them to create a ton of talismans rather than a bunch of TW equipment).
Incorporating multiple Armor Talismans within their armor would let them be shielded from the heat and damage of entering an atmosphere, and the 'leftover' charges could be used as magic FFs while fighting on the ground.
The problem is controlling the fall so the people inside don't black out due to spins and buffetings.
Re: Entering Atmosphere
Posted: Mon Aug 29, 2016 6:08 pm
by dragonfett
I was thinking of allowing the spell Fly as the Eagle allow them control so they wouldn't be tumbling all over the place.
Re: Entering Atmosphere
Posted: Sat Sep 03, 2016 9:12 am
by ShadowLogan
dragonfett wrote:Could a person in Full EBA (or has some other protection from the vacuum of space and sufficient air) use the spell/talisman Impervious to Fire/Energy to avoid damage from entering a planet's atmosphere?
If you could there would not be a need for the Level 6 Space Magic Spell known as "Magic Reentry Bubble" (DB13 Fot3G pg117 starts on bottom of left column and completes at top of right column). The spell notes that it allows one to "survive the heat, stress and turbulence of reentry into an atmosphere without burning up or tearing apart".
The existence of this spell indicates one of two things:
A). existing spells aren't up to the task (contrary to the way they are presented)
B). existing spells, options exist that might be up to the task result in added complexity due to multiple castings/activations which spurred development of a more reliable spell option (1 spell vs multiple others)
dragonfett wrote:No, but there are other options for that (Contra-Grav Packs, Fly as the Eagle, etc.).
An option like a Contra-Grav Pack would negate the need for spells like Impervious to Fire/Energy since you could enter at a sufficient slow velocity.
Then again if your a magic using faction wouldn't some type of teleport/rift be faster to deploy troops than a glorified parachute drop?
dragonfett wrote:In your opinion, how much damage would be caused by hitting the air itself, and at what speed would you have to slow down to so that you are no longer taking damage from just moving through the air?
For an Earth type world You are hitting the Earth's atmosphere at approx. 7.68kps per second (REAL orbital velocity). RUE (and RMB, I'm using RUE for this for citations) has several ways to consider this:
1). You could treat it as the equivalent of an aircraft crash landing (unsuccessful) (found on pg364)
2). High Speed Crash (pg356 part of an optional rule), which passes damage through the armor (80kph = ~0.02kps, and 32kph = ~0.009kps) works out to doing ~850d4 assuming near earth orbital velocities at entry
3). Misc Collision Damage (pg345, which is what hitting the atmosphere could be considered) does 2d4 per 16kph (~0.004kps) works out to 3840d4SDC (or 38d4MD)
4). Treat as Fall Damage (both pg356 and pg345 have examples)
If you use Palladium Mach 5 (~1.7kps) the damage is less obviously, but still no less lethal potentially
drewkitty wrote:If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
Spaceship One never achieves real world orbital speed. It isn't even close. The X-15 is known to have flown just as high, but also faster and even it doesn't even get close to orbital Velocity. SpaceshipOne is closer to an X-15 (and cancelled X-33/X-34 programs) than the Space Shuttle (and other manned spacecraft).
The way you have this statement worded it can be taken that that Spaceship One went from ~7.68kps (real world minimum orbital velocity) to ~0.056kps (200mph), which it DID NOT DO. Between White Knight carrier and SpaceshipOne they don't impart that much velocity (its Mach 3.09 maximum speed translates into ~0.98kps) and their propulsion system wasn't used to reduce speed at all.
You are correct that if you could reduce your re-entry velocity you reduce the amount of heat you have to manage. The main problem is that by real world technology that is impractical using their propulsion systems. Palladium "physics" has orbital speed at Mach 5 (far short of the Mach 25 in real life), and doesn’t seem concerned with endurance in a lot of cases preferring an extended "atmospheric" flight model so you could change velocities and such w/o issue. Which isn't going to help a guy in EBA, though if we give him/her/it a contra-grav pack it negates the entire issue.
Re: Entering Atmosphere
Posted: Sat Sep 03, 2016 3:51 pm
by dragonfett
ShadowLogan wrote:dragonfett wrote:Could a person in Full EBA (or has some other protection from the vacuum of space and sufficient air) use the spell/talisman Impervious to Fire/Energy to avoid damage from entering a planet's atmosphere?
If you could there would not be a need for the Level 6 Space Magic Spell known as "Magic Reentry Bubble" (DB13 Fot3G pg117 starts on bottom of left column and completes at top of right column). The spell notes that it allows one to "survive the heat, stress and turbulence of reentry into an atmosphere without burning up or tearing apart".
The existence of this spell indicates one of two things:
A). existing spells aren't up to the task (contrary to the way they are presented)
B). existing spells, options exist that might be up to the task result in added complexity due to multiple castings/activations which spurred development of a more reliable spell option (1 spell vs multiple others)
C). Braden Campbell never considered the possibility that existing spells could achieve this effect.
Can we get Braden to comment on this?
Re: Entering Atmosphere
Posted: Sat Sep 03, 2016 8:42 pm
by drewkitty ~..~
ShadowLogan wrote:snip...
drewkitty wrote:If, like with Spaceship One, they killed their orbital speed before hitting atmo, as to be under 200 mph relative to the planet's surface, they they could fall safely to para-/Grav-chute altitudes.
Spaceship One never achieves real world orbital speed. It isn't even close. The X-15 is known to have flown just as high, but also faster and even it doesn't even get close to orbital Velocity. SpaceshipOne is closer to an X-15 (and cancelled X-33/X-34 programs) than the Space Shuttle (and other manned spacecraft).
The way you have this statement worded it can be taken that that Spaceship One went from ~7.68kps (real world minimum orbital velocity) to ~0.056kps (200mph), which it DID NOT DO. Between White Knight carrier and SpaceshipOne they don't impart that much velocity (its Mach 3.09 maximum speed translates into ~0.98kps) and their propulsion system wasn't used to reduce speed at all.
You are correct that if you could reduce your re-entry velocity you reduce the amount of heat you have to manage. The main problem is that by real world technology that is impractical using their propulsion systems. Palladium "physics" has orbital speed at Mach 5 (far short of the Mach 25 in real life), and doesn’t seem concerned with endurance in a lot of cases preferring an extended "atmospheric" flight model so you could change velocities and such w/o issue. Which isn't going to help a guy in EBA, though if we give him/her/it a contra-grav pack it negates the entire issue.
Does not anyone read the whole topic before they post?*sarcasm*
You might be able to tell that I'm sick of it from the first round of pointlessness.
Re: Entering Atmosphere
Posted: Sun Sep 04, 2016 7:44 am
by ShadowLogan
dragonfett wrote:ShadowLogan wrote:dragonfett wrote:Could a person in Full EBA (or has some other protection from the vacuum of space and sufficient air) use the spell/talisman Impervious to Fire/Energy to avoid damage from entering a planet's atmosphere?
If you could there would not be a need for the Level 6 Space Magic Spell known as "Magic Reentry Bubble" (DB13 Fot3G pg117 starts on bottom of left column and completes at top of right column). The spell notes that it allows one to "survive the heat, stress and turbulence of reentry into an atmosphere without burning up or tearing apart".
The existence of this spell indicates one of two things:
A). existing spells aren't up to the task (contrary to the way they are presented)
B). existing spells, options exist that might be up to the task result in added complexity due to multiple castings/activations which spurred development of a more reliable spell option (1 spell vs multiple others)
C). Braden Campbell never considered the possibility that existing spells could achieve this effect.
Can we get Braden to comment on this?
While Campbell wrote the book, the Space Magic section is specifically identified as being done by Kevin Siembieda & Carl Gleba. So C). is more likely to refer to who ever wrote the spell in question and maybe the editor (if they changed it).
If we view the MREB as a combination of spell effects, 20PPE for 10minutes per level is fairly attractive compared to using multiple spells for the same overall effect, especially when you consider that those multiple spells have different durations which means more PPE being spent to keep it in place to achieve the same effects:
-Energy Field is 10PPE and goes for 1minute per level for the bubble itself (closest/cheapest common invocation I could find that was applicable)
-Immunity to Fire at 5PPE for 5minutes for fire/heat protection
-Float in Air to slow for landing (which MREB does) phase that's another 5PPE for 2.5minutes per level
That's 20PPE right there (more is likely if you do any spell alterations), given the variable durations of each spell you might have to cast one or more again for full protection (EF or ItF, FiA probably doesn't need to be cast until that phase). The spell will also deposit you near a ley line (so recharge your PPE if need be).