Microgravity 101

What Is Microgravity?

Microgravity is the condition where the force of gravity is not zero, but extremely small. Microgravity is typically between 1 thousandth and 1 millionth of Earth’s gravity.

Despite what people say, the International Space Station isn’t in “zero-G”. It’s actually in microgravity. The astronauts feel weightless not because there’s no gravity, but because they’re in continuous freefall, orbiting the Earth at high speed.

It’s like being on a roller coaster…forever.

Why Does It Matter?

In microgravity:

• Fluids don’t behave the same way (no convection, no sedimentation)
• Cells grow differently (cytoskeletons, morphology, gene expression)
• Combustion is strange (flames are spherical, oxygen diffuses differently)
• Crystals form more perfectly (used in pharma, protein crystallization)

For scientists and engineers, this means:

• Microgravity is a unique experimental condition
• It can reveal behaviors masked by Earth gravity
• It can enable new classes of experiments, materials, and medicines

Where It Shows Up in Space

Common Misconceptions

• ❌ “There’s no gravity in space.”
  ✅ Gravity is always present. What you feel as “weightlessness” is actually freefall.

• ❌ “Microgravity and zero-G are the same.”
  ✅ Zero-G is idealized; microgravity is measurable (10⁻³G to 10⁻⁶G range).

• ❌ “Microgravity doesn’t affect experiments much.”
  ✅ It can profoundly change fluid behavior, biology, and crystal formation.

How Spark Gravity Connects to This

At Spark Gravity, we’re focused on programmable gravity. This includes 0G, partial-G, and full-G environments.

Microgravity is one end of the spectrum, but most research today only happens in all-or-nothing environments: 0G on the ISS, or 1G on Earth.

We want to fill the gaps to enable scientists to:

• Control gravity like a variable
• Simulate environments like the Moon (0.16G), Mars (0.38G), or deep space
• Run long-duration studies without needing a full space station

And for the record: we love microgravity. But we also want to give researchers the power to tune G to their hypothesis.

Want to Go Deeper?

• NASA: What is Microgravity?
• Wikipedia: Microgravity Bioprinting
• NASA: The Benefits of Microgravity (μg)
• Coming soon: Drop Towers 101 →