I have this planet that is mostly composed of an unknown acid. Lets name this acid, Substance X. However we can survive on this planet with basic rubber suits, as this acid cannot burn through rubber nor metal. The acid is formed when pure oxygen hits a noble gas we will name Substance C. Substance C is heavier than air and is found at the ground. The planet produces an infinite amount of these gasses, and the oxygen comes out of vents in the ground from an unknown source. Many people who have tried to enter these vents are either burned alive or are terminated by asphyxiation. When Substance C is burned at high temperatures, it will explode and then turn into CO2A (A brother to CO2) which then can enable plant life.

Note: When Substance C is burned, It explodes in a cyan color before disappearing.

Question: How will I be able to land a rocket to inhabit the planet?

  • $\begingroup$ Is the CO2 you mention a combination of oxygen and substance C, or carbon dioxide? If the latter, where is the carbon coming from? $\endgroup$
    – Abigail
    Apr 21, 2021 at 16:16
  • $\begingroup$ The CO2 is a brother to carbon dioxide. It is breathable by life forms $\endgroup$ Apr 21, 2021 at 16:18
  • $\begingroup$ Also i need a name for my planet. Anyone have any good ideas? $\endgroup$ Apr 21, 2021 at 16:30
  • $\begingroup$ that does not answer the question where the carbon is coming from; neither the noble gas, nor oxygen is carbon. And what do you mean by "a brother to carbon dioxide"? How does it differ? $\endgroup$
    – Abigail
    Apr 21, 2021 at 16:44
  • $\begingroup$ CO2 has an unknown chemical that makes it visible that our scientists havent figured out. I might just name it CO2A for now $\endgroup$ Apr 21, 2021 at 16:51

3 Answers 3


It looks like xenon tetraoxide could be a candidate for your gas.


Xenon tetroxide is a chemical compound of xenon and oxygen with molecular formula XeO4, remarkable for being a relatively stable compound of a noble gas. It is a yellow crystalline solid that is stable below −35.9 °C; above that temperature it is very prone to exploding and decomposing into elemental xenon and oxygen (O2)

If you are up to making your world around this exotic chemical that would be cool. Or maybe if your chemistry is not that strong instead of Xe you could use some undiscovered noble gas of higher molecular weight than oganesson so you can assert undiscovered chemostry and not get called out by people who groove on calling out chemistry errors in works of fiction. They are out there, those folks.

I could imagine that a descending chemical rocket or a hot thing entering at orbital speeds might set off an explosion of all the accumulated substance C. Two strategies

1: Set it all off in advance. Drop some bombs, then after a minute or two follow them. Good stuff for an anime as the exploding green clouds of flame will be below your falling characters. The bombs will have detonated all available substance C in their path and it will be safe for your people. It might be kind of a mess on the ground after all the upblowing. The substance C will reaccumulate so no smoking once you are down.

2: Glide in easy. You people glide down from orbit, very slowly shedding velocity in their flying squirrel suits. Nice and easy, nice and easy, not stirring things up. It will take a while so they should have onboard music, or radio connection with their peers to play 20 questions.

thinking about coming down behind the bombs - there will be phenomenal updrafts of hot oxygen and xenon as the XeO4 dissociates. It might do a lot to slow down reentry.

  • $\begingroup$ I would probably pick number 2 because any explosions will cause a nuclear explosion or turn the oxygen vents, into massive gas powered grills. $\endgroup$ Apr 21, 2021 at 16:10
  • $\begingroup$ @JosephCasey - for the oxygen to burn something it must have something to burn like reduced carbon. If it is just oxygen and xenon what will burn? Once the bombs go off you will have free xenon and oxygen which will be fine. As regards a nuclear explosion I cant see the mechanism for that to happen. $\endgroup$
    – Willk
    Apr 21, 2021 at 16:12
  • $\begingroup$ And I might be sure to give the men a solar charger to charge their communication and music deviced. $\endgroup$ Apr 21, 2021 at 16:13
  • 2
    $\begingroup$ Nope. Oxygen needs something to react with that can burn. That is what happens when we breathe - oxygen reacts with food carbon molecules. That is why we don't ignite our atmosphere when we make a campire. $\endgroup$
    – Willk
    Apr 21, 2021 at 16:15
  • 1
    $\begingroup$ @Willk campires: the lesser known cousins of vampires that feed exclusively on campers :) $\endgroup$ Apr 22, 2021 at 5:04

I don't know about the accuracy of all the other elements in your post, but if the bottom line question is "How will I be able to land a rocket to inhabit the planet?" then you can always land with a parachute. Just turn off the fire before you enter the atmosphere. If your pilots calculate the trajectory just right, free fall will do the rest, and you wont even burn up in entry.

Quite a bunch of heavy things have landed from great heights. Military supplies in bulk, returning space capsules (proof that this can be done), even Elephants. And, at least one dude jumped down from space.

Now, getting the rocket back up into space... ?

This might solve both problems, but its handwavy: If your astronauts are arriving at another planet, then we can assume much higher level of technology than we have now. So how about anti-gravity? They'd know about the acidity and explosiveness (they'd have analyzed with telescopes and sent probes to verify) so they'd be prepared for it.

  • $\begingroup$ Another thing to consider is that the landing crew might be fully aware that its a one way trip down(?) $\endgroup$
    – Len
    Apr 21, 2021 at 16:57

Heat shield, parachute and (air) pressure

I'm assuming that the rocket can't just land on rocket power due to the burning, or it would render the whole question moot.

We can look at current ways of getting people down from orbit. They require a (relatively) gentle deceleration as well as gentle landing. What mostly happens is that a capsule will slam into the atmosphere from orbit, starting to slow it down. The heat shields will absorb/redirect the heat generated from the friction and air compression. Afterwards parachutes are deployed for further descent. Rockets might be used for the correct orientation before parachutes are deployed.

Landing in water can be done without breaking rockets, but is still sometimes done for a more smooth landing. Landing on land as far as I can find will always require breaking rockets. If there's already airborne infrastructure on the planet you might capture the capsule mid-air.

Now you only need to replace the breaking rockets. Chemical processes have a lot of power, which is why they are used. Still, if you add huge compartments with compressed air/liquid you can potentially get the same results. Just be mindful it'll take a lot more weight and construction, as well as that the propulsion is likely less strong and cannot continue as long.

If you only want to land materials then parachutes and heat shields can be enough in many cases.


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