Reconfigurable Space Computing Lab · Cal Poly Pomona
BONES IN SPACE
SIMULATOR
How gravity shapes the human skeleton — across worlds, across time.
DESIGNED BY
Dr. Mohamed El-Hadedy
Director of the Reconfigurable Space Computing Laboratory California State Polytechnic University, Pomona
1
THE MECHANISM
Bone is living, responsive tissue
Bone constantly remodels itself in response to mechanical loads — Wolff's Law. Two cell types drive the balance, and microgravity tips it toward breakdown.
OSTEOBLASTS
Builders
Synthesize new bone matrix. Activated by mechanical loading. Rise slowly in flight (~7%/month formation marker increase).
OSTEOCLASTS
Resorbers
Break down bone tissue. Multinucleated. In microgravity, resorption markers plateau at +113% within ~11 days.
"Spaceflight-related changes in bone density depend on the position of the skeletal-site relative to the gravitational vector."
— Stavnichuk et al., npj Microgravity 6:13 (2020)
2
THE EVIDENCE
Trabecular bone thins in microgravity
Drag the slider to advance time on the ISS at ~0g. Watch the internal trabecular network thin out — same skeleton, but losing scaffolding. Pooled BMD data from 148 astronauts (Stavnichuk 2020).
EARTH · 1g · pre-flight
100%
LOWER-LIMB BMD
baseline
0 mo
Pre-flight1mo2mo3mo4mo5mo6mo (full ISS)
LUMBAR SPINE & PELVIS
−6.2%
CI [−6.7, −5.6]
LOWER LIMBS
−5.4%
CI [−6.0, −4.9]
SKULL (FLUID SHIFT)
+2.2%
CI [+1.1, +3.3]
PER MONTH, LOWER LIMBS
−0.8%
CI [−1.1, −0.5]
3
ACROSS WORLDS
What we know by environment
Click a world to load its gravity into the live simulator below. Microgravity is well-studied; partial gravity is mostly a research gap.
YOUR SELECTION FEEDS THE SIMULATOR BELOW
4
LIVE SIMULATOR
No world loaded yet — pick one above, or use the controls below directly.
Osteoblasts (build) Osteoclasts (resorb) Released minerals
RESORPTION RATE
100%
% pre-flight · Stavnichuk 2020
FORMATION RATE
100%
% pre-flight · Stavnichuk 2020
LOWER-LIMB BMD CHANGE
0.0%
computed from −0.8%/mo at 0g
5
BIOLOGICAL BONE AGE ESTIMATOR
CHRONOLOGICAL AGE
35
BIOLOGICAL BONE AGE
35
no aging acceleration
Based on 0.5–1%/yr age-related BMD decline (Berger 2008, Daly 2013); ISS 6 mo loss ≈ ~5–10 yr aging (Gabel 2022).
Educational analogy — not a forensic measurement.