If the shuttle had more power could lt slow down for re-entry, re-enter like a jet, not worry re heat or angle

Question

space shuttle, upon re-entry generates incredible heat on the skin of the shuttle. It enters at 25,000 miles per hour. If it had a nuclear reactor on board to generate power allowing it to slow down, enter at any angle and it could enter in the direction of the earth's rotation, instead of against it. This would eliminate much of the danger of re-entry. Is this possible?

Answer 1

Hi. Yes, with enough power the shuttle could enter the atmosphere at a much slower speed. But it would still want to enter at the same direction as the Earth's rotation.

Answer 2

More power? It has no power at all. During re-entry, the shuttle is a gliding brick with stubby wings. At landing, the glide slope is 19 to 20 degrees. By comparison, a commercial airliner has a glide slope of 2.5 to 3.0 degrees.

In theory, a large enough nuclear electric propulsion (NEP) system could allow a slow, constant-velocity re-entry a la Buck Rogers. But, we don't really know how to build one that large. In fact, right now we can't build one at all. Additionally, weight is the enemy. A large enough NEP might almost eliminate the payload-carrying capability of the craft rendering it fairly useless.

BTW, the shuttle's orbital and reentry tracks are in same direction as the earth's rotation. Why? It would require much more energy to get to orbit if it didn't. The earth's rotational velocity at Cape Canaveral is 934 miles per hour. So, to achieve orbit going the other way, you'd need an extra 934 mph which means more fuel. More fuel weighs more which means carrying even more fuel.

Answer 3

I think the consensus here has addressed your point. There's an interesting implication to your question, though, that I'd like to look at.

enginerd pointed out that the Shuttle would have to carry fuel up into space, in order to use it as part of a braking manuver.

But down the road when - hopefully - we've scrapped the Shuttle and have gotten serious about setting up space-based industry and returning cargo and people to Earth, it may well be that some future shuttles will be fueled in orbit, perhaps using liquid oxygen cracked from the lunar crust in combination with some fuel from a carbonaceous asteroid or comet's volatiles.

As for using a nuclear engine here... I don't see a benefit commensurate with the risk. Nukes would be great for deep space or a lunar transfer tug, though.

Doubtlessly as time goes by engineers will want to take a closer look at the benefits of a de-orbit profile more controllable than what is practical now.

Answer 4

sure it is possible.

the only problem is that to slow down you need fuel. And the fuel you're left with at the end of the mission, you need to carry it up there. And each pound that you get up there requires a lot more pounds of fuel.

so to have a space shuttle with ample fuel reserves at the time of re-entry, you'd need massive amounts of fuel, so much so that you'd have no allowance for any scientific equipement or satellites at launch time.

which would rather defeat the purpose of the whole thing.

that's the whole point of the design: you don't use any fuel to come back. And it is better than the capsules because up to a point you can control where you land, and you can land on an airport which saves a mission to pick you up in the middle of the ocean.

Answer 5

One thing...it re-enters the atmosphere at slightly less than the 17500 mph of orbital speed, not 25000 miles an hour. The energy that it took to boost the orbiter to orbital speed has to be expended to land it. Currently that is by it's slow descent and the heat involved is absorbed and expelled by the heat shield, tires, brakes, and parachute. You would have to have the same energy as the two SRBs and the 3 main engines to 'stop' it for a more vertical descent (neglecting consumables, astronauts, and equipment left in orbit). Interestingly, and in another vein, in terms of velocity, it is easier to land a vehicle on Mars than it is to land it on the (much closer) moon, because the atmosphere helps slow the descent. Not that Mars has anything to do with landing the shuttle.

Answer 6

Yes, in principle, but if you're going to carry that extra fuel for re-entry, you're going to need much more fuel for takeoff. It's a completely different situation from an airliner making a return transatlantic crossing without refuelling, which only requires about twice as much fuel as a one way trip. Unlike an airliner, a space shuttle or rocket's mass on takeoff is mostly fuel. You make a good point; only nuclear energy could get around this problem; for a chemical rocket to cancel its west-to-east orbital velocity would require a prohibitive take-off fuel load.

Answer 7

yes, but the weight of the extra power reactor, would be over do in it. and 2 make such a reactor would take years ,because we have 2 make the reactor 100% self and fitted it to the shuttle, that would take time.

Answer 8

yes, you have to slow down (relative to earth) somehow

it would be possible to use thrust to match velocities with the earth's surface and use thrust to gently descend to earth

the problem of course is fuel

how are you going to carry all that fuel out into space?

think about those big attached tanks as well as all the shuttle primary rocket fuel

notice how much fuel it takes to get them up there

a descent like I described would take almost that much to land

and to boost that fuel up there you would have to have more fuel at take off, which requires more fuel and you see where it goes

Answer 9

Good question and some great answers.

This forum is getting better at last, now that we haven't got that Mars thing going on all the time, and people have quietened down about moon landing hoaxes.

Well done.