4 ms·
That's not really how it works. If Earth's gravity were 1.3% stronger, you'd need about 0.6% (√1.013) more delta-v to escape Earth, or about an extra 70m/s. Tha
by nearbuy 7y ago
That's not really how it works. If Earth's gravity were 1.3% stronger, you'd need about 0.6% (√1.013) more delta-v to escape Earth, or about an extra 70m/s. That's not hard to achieve. Increasing the total mass to dry mass ratio by about 0.6% would do it (and the Saturn 5 was about 85% fuel) since ln(x*1.006) = ln(x) + ln(1.006) ≈ ln(x) + 0.006.
Someone else posted somewhere that if the Earth was about 3x heavier, we wouldn't be able to use chemical rockets to escape.
- CobrastanJorji 7y agoIf the Earth were 3x heavier, birds wouldn't be able to fly, at least not the way they are now. Sparrows can barely get airborne when they're full, let alone at triple their weight.
- ars 7y agoAir density would be three times higher though. So they might still be able to fly.
- CobrastanJorji 7y agoOoo, that's a good point!
- icebraining 7y ago> at least not the way they are now. Yeah, but they wouldn't be, because the extra mass would have influenced their evolution.
- rexer 7y agoExtra weight. If gravity is the only thing changed, mass would remain constant.
- icebraining 7y agoSince the discussion is about "earth's gravity", I'm assuming the change would be in its mass, not in the universal gravitational constant, which is not Earth-specific.
- rocqua 7y agoDid that take into account the possibility of an air breathing first stage?
- jccooper 7y agoProbably not. But, while an air-breather would be more useful on a larger planet, it would still be the case that almost all of the space launch system's work must be done outside the sensible atmosphere. Air breathing would only add the tiniest margin to "chemically escapable planets."