# Question about reentry from space ~

**URL:** <https://boards.straightdope.com/t/question-about-reentry-from-space/160799>\
**Category:** Factual Questions\
**Created:** [March 12, 2003, 11:35am UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799 "2003-03-12T11:35:09Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![darksight](https://avatars.discourse-cdn.com/v4/letter/d/3da27b/32.png) [@darksight](https://boards.straightdope.com/u/darksight)\
**Post date:** [March 12, 2003, 11:35am UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799/1 "2003-03-12T11:35:09Z")

</div>

Why is it that ships returning from space have to enter at such a speed that they risk burning up or skipping off into outer space? Why can’t they slow down before reentry?  
Obviously I’m missing something very simple here that someone can explain to me.

:smack:

---

<div class="post-metadata">

**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\
**Post date:** [March 12, 2003, 11:39am UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799/2 "2003-03-12T11:39:21Z")

</div>

Because if they slow down by firing rockets, they’d have to carry a whole lot more fuel.

---

<div class="post-metadata">

**Author:** ![darksight](https://avatars.discourse-cdn.com/v4/letter/d/3da27b/32.png) [@darksight](https://boards.straightdope.com/u/darksight)\
**Post date:** [March 12, 2003, 11:44am UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799/3 "2003-03-12T11:44:41Z")

</div>

Seems they could find a way to refuel once they are in orbit. That doesn’t seem to me to be the whole problem.

I mean even slowing to say 10 times the speed of sound instead of 20 or so would help.

---

<div class="post-metadata">

**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [March 12, 2003, 12:06pm UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799/4 "2003-03-12T12:06:32Z")

</div>

Fuel _is_ the whole problem. It’s extremely expensive to lift fuel into orbit. One pound of fuel saved is one pound of extra payload you can take into orbit. Why waste fuel when you can use the atmosphere to slow you down?

---

<div class="post-metadata">

**Author:** ![ChalkPit](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@ChalkPit](https://boards.straightdope.com/u/ChalkPit)\
**Post date:** [March 12, 2003, 2:02pm UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799/5 "2003-03-12T14:02:55Z")

</div>

But if u DID have enough fuel to do it, could you just slow your orbital speed right down to practically nothing, then ‘drop’ down to earth with almost no re-entry heating at all ?

---

<div class="post-metadata">

**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [March 12, 2003, 2:20pm UTC](https://boards.straightdope.com/t/question-about-reentry-from-space/160799/6 "2003-03-12T14:20:16Z")

</div>

> [@](#):
>
> \*Originally posted by ChalkPit \*  
> **But if u DID have enough fuel to do it, could you just slow your orbital speed right down to practically nothing, then ‘drop’ down to earth with almost no re-entry heating at all ?**

Yes you could. I don’t see the point though, considering how much fuel it takes to kill 7 km/s of speed. And rocket engines tend to be even less reliable than thermal shields.